Question: What is the mechanism of inflammatory response and pathogenesis of COVID-19 cases?

Title: COVID-19 - toward a comprehensive understanding of the disease. Content: The evidence on the pathophysiology of the novel coronavirus SARS-CoV-2 infection is rapidly growing. Understanding why some patients suffering from COVID-19 are getting so sick, while others are not, has become an informal imperative for researchers and clinicians around the globe. The answer to this question would allow rationalizing the fear surrounding this pandemic. Understanding of the pathophysiology of COVID-19 relies on an understanding of interplaying mechanisms, including SARS-CoV-2 virulence, human immune response, and complex inflammatory reactions with coagulation playing a major role. An interplay with bacterial co-infections, as well as the vascular system and microcirculation affected throughout the body should also be examined. More importantly, a comprehensive understanding of pathological mechanisms of COVID-19 will increase the efficacy of therapy and decrease mortality. Herewith, presented is the current state of knowledge on COVID-19: beginning from the virus, its transmission, and mechanisms of entry into the human body, through the pathological effects on the cellular level, up to immunological reaction, systemic and organ presentation. Last but not least, currently available and possible future therapeutic and diagnostic options are briefly commented on.

Title: COVID-19 - Toward a comprehensive understanding of the disease Content: The evidence on the pathophysiology of the novel coronavirus SARS-CoV-2 infection is rapidly growing. Understanding why some patients suffering from COVID-19 are getting so sick, while others are not, has become an informal imperative for researchers and clinicians around the globe. The answer to this question would allow rationalizing the fear surrounding this pandemic. Understanding of the pathophysiology of COVID-19 relies on an understanding of interplaying mechanisms, including SARS-CoV-2 virulence, human immune response, and complex inflammatory reactions with coagulation playing a major role. An interplay with bacterial co-infections, as well as the vascular system and microcirculation affected throughout the body should also be examined. More importantly, a compre-hensive understanding of pathological mechanisms of COVID-19 will increase the efficacy of therapy and decrease mortality. Herewith, presented is the current state of knowledge on COVID-19: beginning from the virus, its transmission, and mechanisms of entry into the human body, through the pathological effects on the cellular level, up to immunological reaction, systemic and organ presentation. Last but not least, currently available and possible future therapeutic and diagnostic options are briefly commented on.

Title: A Dynamic Immune Response Shapes COVID-19 Progression Content: The inflammatory response to SARS-coronavirus-2 (SARS-CoV-2) infection is thought to underpin COVID-19 pathogenesis. We conducted daily transcriptomic profiling of three COVID-19 cases and found that the early immune response in COVID-19 patients is highly dynamic. Patient throat swabs were tested daily for SARS-CoV-2, with the virus persisting for 3 to 4 weeks in all three patients. Cytokine analyses of whole blood revealed increased cytokine expression in the single most severe case. However, most inflammatory gene expression peaked after respiratory function nadir, except expression in the IL1 pathway. Parallel analyses of CD4 and CD8 expression suggested that the pro-inflammatory response may be intertwined with T cell activation that could exacerbate disease or prolong the infection. Collectively, these findings hint at the possibility that IL1 and related pro-inflammatory pathways may be prognostic and serve as therapeutic targets for COVID-19. This work may also guide future studies to illuminate COVID-19 pathogenesis and develop host-directed therapies.

Title: A dynamic immune response shapes COVID-19 progression Content: The inflammatory response to SARS-coronavirus-2 (SARS-CoV-2) infection is thought to underpin COVID-19 pathogenesis We conducted daily transcriptomic profiling of three COVID-19 cases and found that the early immune response in COVID-19 patients is highly dynamic Patient throat swabs were tested daily for SARS-CoV-2 with the virus persisting for 3-4 weeks in all three patients Cytokine analyses of whole blood revealed increased cytokine expression in the single more severe case However, most inflammatory gene expression peaked after respiratory function nadir, except those in the IL1 pathway Parallel analyses of CD4 and CD8 expression suggested that the pro-inflammatory response may be intertwined with T-cell activation that could exacerbate disease or prolong the infection Collectively, these findings hint at the possibility that IL1 and related pro-inflammatory pathways may be prognostic and serve as therapeutic targets for COVID-19 This work may also guide future studies to illuminate COVID-19 pathogenesis and develop host-directed therapies

Title: Comprehensive Transcriptomic Analysis of COVID-19 Blood, Lung, and Airway Content: Abstract SARS-CoV2 is a previously uncharacterized coronavirus and causative agent of the COVID-19 pandemic. The host response to SARS-CoV2 has not yet been fully delineated, hampering a precise approach to therapy. To address this, we carried out a comprehensive analysis of gene expression data from the blood, lung, and airway of COVID-19 patients. Our results indicate that COVID-19 pathogenesis is driven by populations of myeloid-lineage cells with highly inflammatory but distinct transcriptional signatures in each compartment. The relative absence of cytotoxic cells in the lung suggests a model in which delayed clearance of the virus may permit exaggerated myeloid cell activation that contributes to disease pathogenesis by the production of inflammatory mediators. The gene expression profiles also identify potential therapeutic targets that could be modified with available drugs. The data suggest that transcriptomic profiling can provide an understanding of the pathogenesis of COVID-19 in individual patients. Graphical Abstract

Title: Pathogenesis of COVID-19 from the Perspective of the Damage-Response Framework Content: The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents the medical community with a significant challenge. COVID-19 is an entirely new disease with disparate clinical manifestations that are difficult to reconcile with a single pathogenic principle. Here, we explain how the flexible paradigm of the “damage-response framework” (DRF) of microbial pathogenesis can organize the varied manifestations of COVID-19 into a synthesis that accounts for differences in susceptibility of vulnerable populations as well as for differing manifestations of COVID-19 disease. By focusing on mechanisms of host damage, particularly immune-mediated damage, the DRF provides a lens to understand COVID-19 pathogenesis and to consider how potential therapies could alter the outcome of this disease.

Title: Pathogenesis of COVID-19 from the Perspective of the Damage-Response Framework Content: The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) presents the medical community with a significant challenge. COVID-19 is an entirely new disease with disparate clinical manifestations that are difficult to reconcile with a single pathogenic principle. Here, we explain how the flexible paradigm of the "damage-response framework" (DRF) of microbial pathogenesis can organize the varied manifestations of COVID-19 into a synthesis that accounts for differences in susceptibility of vulnerable populations as well as for differing manifestations of COVID-19 disease. By focusing on mechanisms of host damage, particularly immune-mediated damage, the DRF provides a lens to understand COVID-19 pathogenesis and to consider how potential therapies could alter the outcome of this disease.

Title: The immune system and COVID-19: Friend or foe? Content: AIM: Coronavirus disease 2019 (COVID-19) is a novel highly contagious infection caused by SARS-CoV-2, which has been became a global public health challenge. The pathogenesis of this virus is not yet clearly understood, but there is evidence of a hyper-inflammatory immune response in critically ill patients, which leads to acute respiratory distress syndrome (ARDS) and multi-organ failure. MATERIAL AND METHODS: A literature review was performed to identify relevant articles on COVID-19 published up to April 30, 2020. The search resulted in 361 total articles. After reviewing the titles and abstracts for inclusion, some irrelevant papers were excluded. Additional relevant articles were identified from a review of citations referenced. KEY FINDINGS: SARS-CoV-2, directly and indirectly, affects the immune system and avoids being eliminated in early stages. On the other hand, the secretion of inflammatory cytokines creates critical conditions that lead to multi-organ failure. SIGNIFICANCE: The immune system which is affected by the virus tries to respond via a cytokine storm and hyperinflammation, which itself leads to further multi-organ damage and even death.

Title: Pharmacological agents under investigation in the treatment of coronavirus disease 2019 and the importance of melatonin Content: Coronavirus disease 2019 (COVID-19) is a life-threatening infectious respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 pandemic causing morbidities and even deaths worldwide revealed that there is urgent need to find pharmacological agents or vaccines. Although there are a lot of agents under investigation, there is no approved agent for the prevention or treatment of the COVID-19 yet. Treatment of patients remains mainly supportive as well as compassionate use of the agents under investigation. It is well established that excessive inflammatory and immune response as well as oxidative injury play a critical role in the pathogenesis of COVID-19. In this review, we aimed to update knowledge about pathogenesis, clinical features and pharmacological treatment of COVID-19 and review the potential beneficial effects of ancient antioxidant, anti-inflammatory and immunomodulatory molecule melatonin for prevention and treatment of COVID-19.

Title: Pharmacological agents under investigation in the treatment of coronavirus disease 2019 and the importance of melatonin. Content: Coronavirus disease 2019 (COVID-19) is a life-threatening infectious respiratory disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 pandemic causing morbidities and even deaths worldwide revealed that there is urgent need to find pharmacological agents or vaccines. Although there are a lot of agents under investigation, there is no approved agent for the prevention or treatment of the COVID-19 yet. Treatment of patients remains mainly supportive as well as compassionate use of the agents under investigation. It is well established that excessive inflammatory and immune response as well as oxidative injury play a critical role in the pathogenesis of COVID-19. In this review, we aimed to update knowledge about pathogenesis, clinical features and pharmacological treatment of COVID-19 and review the potential beneficial effects of ancient antioxidant, anti-inflammatory and immunomodulatory molecule melatonin for prevention and treatment of COVID-19.

Title: SARS-CoV-2 infection: the role of cytokines in COVID-19 disease Content: COVID-19 disease, caused by infection with SARS-CoV-2, is related to a series of physiopathological mechanisms that mobilize a wide variety of biomolecules, mainly immunological in nature. In the most severe cases, the prognosis can be markedly worsened by the hyperproduction of mainly proinflammatory cytokines, such as IL-1, IL-6, IL-12, IFN-γ, and TNF-α, preferentially targeting lung tissue. This study reviews published data on alterations in the expression of different cytokines in patients with COVID-19 who require admission to an intensive care unit. Data on the implication of cytokines in this disease and their effect on outcomes will support the design of more effective approaches to the management of COVID-19.

Title: COVID-19 : physiopathologie d'une maladie à plusieurs visages./ [COVID-19: Pathogenesis of a multi-faceted disease] Content: SARS-CoV-2 infection, named COVID-19, can lead to a dysregulated immune response and abnormal coagulation responsible for a viral sepsis. In this review, we specify physiopathological mechanisms of each phase of COVID-19 - viral, immune and pro-thrombotic - notably because they involve different treatment. Finally, we specify the physiopathological mechanisms of organ injury.

Title: SARS-CoV-2 infection: The role of cytokines in COVID-19 disease Content: COVID-19 disease, caused by infection with SARS-CoV-2, is related to a series of physiopathological mechanisms that mobilize a wide variety of biomolecules, mainly immunological in nature. In the most severe cases, the prognosis can be markedly worsened by the hyperproduction of mainly proinflammatory cytokines, such as IL-1, IL-6, IL-12, IFN-Î³, and TNF-α, preferentially targeting lung tissue. This study reviews published data on alterations in the expression of different cytokines in patients with COVID-19 who require admission to an intensive care unit. Data on the implication of cytokines in this disease and their effect on outcomes will support the design of more effective approaches to the management of COVID-19.

Title: Early Insights into Immune Responses during COVID-19 Content: Coronavirus disease-2019 (COVID-19) is caused by the newly emerged virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was recently declared as a pandemic by the World Health Organization. In its severe form, the disease is characterized by acute respiratory distress syndrome, and there are no targeted intervention strategies to treat or prevent it. The immune response is thought to both contribute to the pathogenesis of disease and provide protection during its resolution. Thus, understanding the immune response to SARS-CoV-2 is of the utmost importance for developing and testing vaccines and therapeutics. In this review, we discuss the earliest knowledge and hypotheses of the mechanisms of immune pathology in the lung during acute infection as well at the later stages of disease resolution, recovery, and immune memory formation.

Title: Early Insights into Immune Responses during COVID-19. Content: Coronavirus disease-2019 (COVID-19) is caused by the newly emerged virus severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and was recently declared as a pandemic by the World Health Organization. In its severe form, the disease is characterized by acute respiratory distress syndrome, and there are no targeted intervention strategies to treat or prevent it. The immune response is thought to both contribute to the pathogenesis of disease and provide protection during its resolution. Thus, understanding the immune response to SARS-CoV-2 is of the utmost importance for developing and testing vaccines and therapeutics. In this review, we discuss the earliest knowledge and hypotheses of the mechanisms of immune pathology in the lung during acute infection as well at the later stages of disease resolution, recovery, and immune memory formation.

Title: SARS-CoV-2 and viral sepsis: observations and hypotheses Content: Since the outbreak of coronavirus disease 2019 (COVID-19), clinicians have tried every effort to understand the disease, and a brief portrait of its clinical features have been identified. In clinical practice, we noticed that many severe or critically ill COVID-19 patients developed typical clinical manifestations of shock, including cold extremities and weak peripheral pulses, even in the absence of overt hypotension. Understanding the mechanism of viral sepsis in COVID-19 is warranted for exploring better clinical care for these patients. With evidence collected from autopsy studies on COVID-19 and basic science research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and SARS-CoV, we have put forward several hypotheses about SARS-CoV-2 pathogenesis after multiple rounds of discussion among basic science researchers, pathologists, and clinicians working on COVID-19. We hypothesise that a process called viral sepsis is crucial to the disease mechanism of COVID-19. Although these ideas might be proven imperfect or even wrong later, we believe they can provide inputs and guide directions for basic research at this moment.

Title: A contemporary review on pathogenesis and immunity of COVID-19 infection Content: Emerging of the COVID-19 pandemic has raised interests in the field of biology and pathogenesis of coronaviruses; including interactions between host immune reactions specific, and viral factors. Deep knowledge about the interaction between coronaviruses and the host factors could be useful to provide a better support for the disease sufferers and be advantageous for managing and treatment of the lung infection caused by the virus. At this study, we reviewed the updated information on the pathogenesis of the COVID-19 and the immune responses toward it, with a special focus on structure, genetics, and viral accessory proteins, viral replication, viral receptors, the human immune reactions, cytopathic effects, and host-related factors.

Title: Inflammatory and Coagulative Considerations for the Management of Orthopaedic Trauma Patients With COVID-19: A Review of the Current Evidence and Our Surgical Experience Content: Mounting evidence suggests that the pathogenesis of coronavirus disease 2019 (COVID-19) involves a hyperinflammatory response predisposing patients to thromboembolic disease and acute respiratory distress. In the setting of severe blunt trauma, damaged tissues induce a local and systemic inflammatory response through similar pathways to COVID-19. As such, patients with COVID-19 sustaining orthopaedic trauma injuries may have an amplified response to the traumatic insult because of their baseline hyperinflammatory and hypercoagulable states. These patients may have compromised physiological reserve to withstand the insult of surgical intervention before reaching clinical instability. In this article, we review the current evidence regarding pathogenesis of COVID-19 and its implications on the management of orthopaedic trauma patients by discussing a case and the most recent literature.

Title: SARS-CoV-2 and viral sepsis: observations and hypotheses Content: Summary Since the outbreak of coronavirus disease 2019 (COVID-19), clinicians have tried every effort to understand the disease, and a brief portrait of its clinical features have been identified. In clinical practice, we noticed that many severe or critically ill COVID-19 patients developed typical clinical manifestations of shock, including cold extremities and weak peripheral pulses, even in the absence of overt hypotension. Understanding the mechanism of viral sepsis in COVID-19 is warranted for exploring better clinical care for these patients. With evidence collected from autopsy studies on COVID-19 and basic science research on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and SARS-CoV, we have put forward several hypotheses about SARS-CoV-2 pathogenesis after multiple rounds of discussion among basic science researchers, pathologists, and clinicians working on COVID-19. We hypothesise that a process called viral sepsis is crucial to the disease mechanism of COVID-19. Although these ideas might be proven imperfect or even wrong later, we believe they can provide inputs and guide directions for basic research at this moment.

Title: COVID-19 Hyperinflammation: What about Neutrophils? Content: COVID-19 is often related to hyperinflammation that drives lung or multiorgan injury. The immunopathological mechanisms that cause excessive inflammation are under investigation and constantly updated. Here, a gene network approach was used on recently published data sets to identify possible COVID-19 inflammatory mechanisms and bioactive genes. First, network analysis of putative SARS-CoV-2 cellular receptors led to the mining of a neutrophil-response signature and relevant inflammatory genes. Second, analysis of RNA-seq data sets of lung cells infected with SARS-CoV-2 revealed that infected cells expressed neutrophil-attracting chemokines. Third, analysis of RNA-seq data sets of bronchoalveolar lavage fluid cells from COVID-19 patients identified upregulation of neutrophil genes and chemokines. Different inflammatory genes mined here, including TNFR, IL-8, CXCR1, CXCR2, ADAM10, GPR84, MME, ANPEP, and LAP3, might be druggable targets in efforts to limit SARS-CoV-2 inflammation in severe clinical cases. The possible role of neutrophils in COVID-19 inflammation needs to be studied further.

Title: Tackle the free radicals damage in COVID-19. Content: COVID-19 is a severe pandemic which has caused a devastating amount of loss in lives around the world, and yet we still don't know how to appropriately treat this disease. We know very little about the pathogenesis of SARS-CoV-2, the virus which induces the COVID-19. However, COVID-19 does share many similar symptoms with SARS and influenza. Previous scientific discoveries learned from lab animal models and clinical practices shed light on possible pathogenic mechanisms in COVID-19. In the past decades, accumulated scientific findings confirmed the pathogenic role of free radicals damage in respiratory virus infection. Astonishingly very few medical professionals mention the crucial role of free radical damage in COVID-19. This hypothesis aims to summarize the crucial pathogenic role of free radical damage in respiratory virus induced pneumonia and suggest an antioxidative therapeutic strategy for COVID-19.

Title: The renin-angiotensin-aldosterone system: Role in pathogenesis and potential therapeutic target in COVID-19. Content: Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 novel coronavirus, has spread worldwide causing high fatality rates. Neither a vaccine nor specific therapeutic approaches are available, hindering the fight against this disease and making better understanding of its pathogenesis essential. Despite similarities between SARS-CoV-2 and SARS-CoV, the former has unique characteristics which represent a great challenge to physicians. The mechanism of COVID-19 infection and pathogenesis is still poorly understood. In the present review, we highlight possible pathways involved in the pathogenesis of COVID-19 and potential therapeutic targets, focusing on the role of the renin-angiotensin-aldosterone system.

Title: The renin-angiotensin-aldosterone system: Role in pathogenesis and potential therapeutic target in COVID-19 Content: Coronavirus disease 2019 (COVID-19), caused by the SARS-CoV-2 novel coronavirus, has spread worldwide causing high fatality rates. Neither a vaccine nor specific therapeutic approaches are available, hindering the fight against this disease and making better understanding of its pathogenesis essential. Despite similarities between SARS-CoV-2 and SARS-CoV, the former has unique characteristics which represent a great challenge to physicians. The mechanism of COVID-19 infection and pathogenesis is still poorly understood. In the present review, we highlight possible pathways involved in the pathogenesis of COVID-19 and potential therapeutic targets, focusing on the role of the renin-angiotensin-aldosterone system.

Title: COVID-19: pathogenesis, genetic polymorphism, clinical features and laboratory findings Content: COVID-19 caused by a novel agent SARS-CoV-2 progressed to a pandemic condition and resulted in a major public health concern worldwide, leading to social and economic issues at the same time. The pathogenesis of COVID-19 starts with the bonding of the virus to ACE2 receptors expressed in many tissues, and the triggered excessive immune response plays a critical role in the course of the disease. The cytokine storm that occurs upon excessive production of pro-inflammatory cytokines is considered responsible for the severe progression of the disease and the organ damage. However, the accurate pathophysiological mechanism of the disease, which progresses with various clinical presentations, is still substantially unknown. While various studies have been conducted on the effect of genetic polymorphism on the course and severity of the disease, the presence of a significant effect has not been proven yet. The clinical course of the disease is variable, with clinical representation ranging from 81% mild course to 14% severe course along with 5% critical course in patients. Asymptomatic course is considered to be higher than expected, although its frequency is not known exactly. Older adults and those with comorbidities are exposed to a more severe disease course. The disease progress with various symptoms, such as fever, cough, dyspnea, malaise, myalgia, taste and smell dysfunctions, diarrhea, and headache. A range of complications (acute respiratory distress syndrome, thromboembolic conditions, arrhythmia and cardiac events, secondary infections) could be seen during the course of the disease. Varied laboratory tests are vital to determine these verity and prognosis of the disease, along with the condition and exposure of the affected systems during thecourse of COVID-19.

Title: [The Agreed Experts' Position of the Eurasian Association of Therapists on Some new Mechanisms of COVID-19 Pathways: Focus on Hemostasis, Hemotransfusion Issues and Blood gas Exchange] Content: The article discusses pathogenesis and treatment of COVID-19. The authors presented state-of-the-art insight into hemostatic disorders in patients with COVID-19 and clinical recommendations on prevention of thrombosis and thromboembolism in patients infected with SARS-CoV-2. The article discussed in detail a new hypothesis proposed by Chinese physicians about a new component in the pathogenesis of COVID-19, namely, about the effect of SARS-CoV-2 virus on the hemoglobin beta-chain and the formation of a complex with porphyrin, which results in displacement of the iron ion. Thus, hemoglobin loses the capability for transporting oxygen, which aggravates hypoxia and worsens the prognosis. The article stated rules of hemotransfusion safety in the conditions of COVID-19 pandemic.

Title: [The Agreed Experts' Position of the Eurasian Association of Therapists on Some new Mechanisms of COVID-19 Pathways: Focus on Hemostasis, Hemotransfusion Issues and Blood gas Exchange]. Content: The article discusses pathogenesis and treatment of COVID-19. The authors presented state-of-the-art insight into hemostatic disorders in patients with COVID-19 and clinical recommendations on prevention of thrombosis and thromboembolism in patients infected with SARS-CoV-2. The article discussed in detail a new hypothesis proposed by Chinese physicians about a new component in the pathogenesis of COVID-19, namely, about the effect of SARS-CoV-2 virus on the hemoglobin beta-chain and the formation of a complex with porphyrin, which results in displacement of the iron ion. Thus, hemoglobin loses the capability for transporting oxygen, which aggravates hypoxia and worsens the prognosis. The article stated rules of hemotransfusion safety in the conditions of COVID-19 pandemic.

Title: Inflammatory and Coagulative Considerations for the Management of Orthopaedic Trauma Patients with COVID-19: A Review of the Current Evidence and Our Surgical Experience Content: Mounting evidence suggests that the pathogenesis of coronavirus disease 2019 (COVID-19) involves a hyperinflammatory response predisposing patients to thromboembolic disease and acute respiratory distress. In the setting of severe blunt trauma, damaged tissues induce a local and systemic inflammatory response through similar pathways to COVID-19. As such, patients with COVID-19 sustaining orthopaedic trauma injuries may have an amplified response to the traumatic insult due to their baseline hyperinflammatory and hypercoagulable state. These patients may have compromised physiological reserve to withstand the insult of surgical intervention before reaching clinical instability. Herein, we review the current evidence regarding pathogenesis of COVID-19 and its implications on the management of orthopaedic trauma patients by discussing a case and the most recent literature.

Title: Devilishly radical NETwork in COVID-19: Oxidative stress, neutrophil extracellular traps (NETs), and T cell suppression Content: Pandemic coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and poses an unprecedented challenge to healthcare systems due to the lack of a vaccine and specific treatment options. Accordingly, there is an urgent need to understand precisely the pathogenic mechanisms underlying this multifaceted disease. There is increasing evidence that the immune system reacts insufficiently to SARS-CoV-2 and thus contributes to organ damage and to lethality. In this review, we suggest that the overwhelming production of reactive oxygen species (ROS) resulting in oxidative stress is a major cause of local or systemic tissue damage that leads to severe COVID-19. It increases the formation of neutrophil extracellular traps (NETs) and suppresses the adaptive arm of the immune system, i.e. T cells that are necessary to kill virus-infected cells. This creates a vicious cycle that prevents a specific immune response against SARS-CoV-2. The key role of oxidative stress in the pathogenesis of severe COVID-19 implies that therapeutic counterbalancing of ROS by antioxidants such as vitamin C or NAC and/or by antagonizing ROS production by cells of the MPS and neutrophil granulocytes and/or by blocking of TNF-α can prevent COVID-19 from becoming severe. Controlled clinical trials and preclinical models of COVID-19 are needed to evaluate this hypothesis.

Title: Hypothesis for potential pathogenesis of SARS-CoV-2 infection--a review of immune changes in patients with viral pneumonia Content: Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with droplets and contact as the main means of transmission Since the first case appeared in Wuhan, China, in December 2019, the outbreak has gradually spread nationwide Up to now, according to official data released by the Chinese health commission, the number of newly diagnosed patients has been declining, and the epidemic is gradually being controlled Although most patients have mild symptoms and good prognosis after infection, some patients developed severe and die from multiple organ complications The pathogenesis of SARS-CoV-2 infection in humans remains unclear Immune function is a strong defense against invasive pathogens and there is currently no specific antiviral drug against the virus This article reviews the immunological changes of coronaviruses like SARS, MERS and other viral pneumonia similar to SARS-CoV-2 Combined with the published literature, the potential pathogenesis of COVID-19 is inferred, and the treatment recommendations for giving high-doses intravenous immunoglobulin and low-molecular-weight heparin anticoagulant therapy to severe type patients are proposed

Title: COVID-19 severity is associated with immunopathology and multi-organ damage Content: COVID-19 is characterised by dysregulated immune responses, metabolic dysfunction and adverse effects on the function of multiple organs. To understand how host responses contribute to COVID-19 pathophysiology, we used a multi-omics approach to identify molecular markers in peripheral blood and plasma samples that distinguish COVID-19 patients experiencing a range of disease severities. A large number of expressed genes, proteins, metabolites and extracellular RNAs (exRNAs) were identified that exhibited strong associations with various clinical parameters. Multiple sets of tissue-specific proteins and exRNAs varied significantly in both mild and severe patients, indicative of multi-organ damage. The continuous activation of IFN-I signalling and neutrophils, as well as a high level of inflammatory cytokines, were observed in severe disease patients. In contrast, COVID-19 in mild patients was characterised by robust T cell responses. Finally, we show that some of expressed genes, proteins and exRNAs can be used as biomarkers to predict the clinical outcomes of SARS-CoV-2 infection. These data refine our understanding of the pathophysiology and clinical progress of COVID-19 and will help guide future studies in this area.

Title: COVID-19: Pathogenesis, Genetic Polymorphism, Clinical Features and Laboratory Findings. Content: COVID-19 caused by a novel agent SARS-CoV-2 progressed to a pandemic condition and resulted in a major public health concern worldwide, leading to social and economic issues at the same time. The pathogenesis of COVID-19 starts with the bonding of the virus to ACE-2 receptors expressed in many tissues, and the triggered excessive immune response plays a critical role in the course of the disease. The cytokine storm that occurs upon excessive production of pro-inflammatory cytokines is considered responsible for the severe progression of the disease and the organ damage. However, the accurate pathophysiological mechanism of the disease, which progresses with various clinical presentations, is still substantially unknown. While various studies have been conducted on the effect of genetic polymorphism on the course and severity of the disease, the presence of a significant effect has not been proven yet. The clinical course of the disease is variable, with clinical representation ranging from 81% mild course to 14% severe course along with 5% critical course in patients. Asymptomatic course is considered to be higher than expected, although its frequency is not known exactly. Older adults and those with comorbidities are exposed to a more severe disease course. The disease progress with various symptoms, such as fever, cough, dyspnea, malaise, myalgia, taste and smell dysfunctions, diarrhea, and headache. A range of complications (Acute Respiratory Distress Syndrome, thromboembolic conditions, arrhythmia and cardiac events, secondary infections) could be seen during the course of the disease. Varied laboratory tests are vital to determine the severity and prognosis of the disease, along with the condition and exposure of the affected systems during the course of COVID-19.

Title: The cytokine storm in COVID-19: An overview of the involvement of the chemokine/chemokine-receptor system Content: In 2019-2020 a new coronavirus named SARS-CoV-2 was identified as the causative agent of a several acute respiratory infection named COVID-19, which is causing a worldwide pandemic. There are still many unresolved questions regarding the pathogenesis of this disease and especially the reasons underlying the extremely different clinical course, ranging from asymptomatic forms to severe manifestations, including the Acute Respiratory Distress Syndrome (ARDS). SARS-CoV-2 showed phylogenetic similarities to both SARS-CoV and MERS-CoV viruses, and some of the clinical features are shared between COVID-19 and previously identified beta-coronavirus infections. Available evidence indicate that the so called "cytokine storm" an uncontrolled over-production of soluble markers of inflammation which, in turn, sustain an aberrant systemic inflammatory response, is a major responsible for the occurrence of ARDS. Chemokines are low molecular weight proteins with powerful chemoattractant activity which play a role in the immune cell recruitment during inflammation. This review will be aimed at providing an overview of the current knowledge on the involvement of the chemokine/chemokine-receptor system in the cytokine storm related to SARS-CoV-2 infection. Basic and clinical evidences obtained from previous SARS and MERS epidemics and available data from COVID-19 will be taken into account.

Title: The Cytokine storm in COVID-19: An overview of the involvement of the chemokine/chemokine-receptor system Content: In 2019-2020 a new coronavirus named SARS-CoV-2 was identified as the causative agent of a several acute respiratory infection named COVID-19, which is causing a worldwide pandemic. There are still many unresolved questions regarding the pathogenesis of this disease and especially the reasons underlying the extremely different clinical course, ranging from asymptomatic forms to severe manifestations, including the Acute Respiratory Distress Syndrome (ARDS). SARS-CoV-2 showed phylogenetic similarities to both SARS-CoV and MERS-CoV viruses, and some of the clinical features are shared between COVID-19 and previously identified beta-coronavirus infections. Available evidence indicate that the so called “cytokine storm” an uncontrolled over-production of soluble markers of inflammation which, in turn, sustain an aberrant systemic inflammatory response, is a major responsible for the occurrence of ARDS. Chemokines are low molecular weight proteins with powerful chemoattractant activity which play a role in the immune cell recruitment during inflammation. This review will be aimed at providing an overview of the current knowledge on the involvement of the chemokine/chemokine-receptor system in the cytokine storm related to SARS-CoV-2 infection. Basic and clinical evidences obtained from previous SARS and MERS epidemics and available data from COVID-19 will be taken into account.

Title: SARS-CoV2 may evade innate immune response, causing uncontrolled neutrophil extracellular traps formation and multi-organ failure Content: We demonstrate that the general clinical conditions, risk factors and numerous pathological and biological features of COVID-19 are analogous with various disorders caused by the uncontrolled formation of neutrophil extracellular traps and their by-products. Given the rapid evolution of this disease's symptoms and its lethality, we hypothesize that SARS-CoV2 evades innate immune response causing COVID-19 progresses under just such an amplifier loop, leading to a massive, uncontrolled inflammation process. This work allows us to propose new strategies for treating the pandemic.

Title: SARS-CoV2 may evade innate immune response, causing uncontrolled neutrophil extracellular traps formation and multi-organ failure. Content: We demonstrate that the general clinical conditions, risk factors and numerous pathological and biological features of COVID-19 are analogous with various disorders caused by the uncontrolled formation of neutrophil extracellular traps and their by-products. Given the rapid evolution of this disease's symptoms and its lethality, we hypothesize that SARS-CoV2 evades innate immune response causing COVID-19 progresses under just such an amplifier loop, leading to a massive, uncontrolled inflammation process. This work allows us to propose new strategies for treating the pandemic.

Title: Serum protein profiling reveals a landscape of inflammation and immune signaling in early-stage COVID-19 infection Content: Coronavirus disease 2019 (COVID-19) is a highly contagious infection and threating the human lives in the world. The elevation of cytokines in blood is crucial to induce cytokine storm and immunosuppression in the transition of severity in COVID-19 patients. However, the comprehensive changes of serum proteins in COVID-19 patients throughout the SARS-CoV-2 infection is unknown. In this work, we developed a high-density antibody microarray and performed an in-depth proteomics analysis of serum samples collected from early COVID-19 (n=15) and influenza (n=13) patients. We identified a large set of differentially expressed proteins (n=125) that participate in a landscape of inflammation and immune signaling related to the SARS-CoV-2 infection. Furthermore, the significant correlations of neutrophil and lymphocyte with the CCL2 and CXCL10 mediated cytokine signaling pathways was identified. These information are valuable for the understanding of COVID-19 pathogenesis, identification of biomarkers and development of the optimal anti-inflammation therapy.

Title: Hypothesis for potential pathogenesis of SARS-CoV-2 infection–a review of immune changes in patients with viral pneumonia Content: Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with droplets and contact as the main means of transmission. Since the first case appeared in Wuhan, China, in December 2019, the outbreak has gradually spread nationwide. Up to now, according to official data released by the Chinese health commission, the number of newly diagnosed patients has been declining, and the epidemic is gradually being controlled. Although most patients have mild symptoms and good prognosis after infection, some patients developed severe and die from multiple organ complications. The pathogenesis of SARS-CoV-2 infection in humans remains unclear. Immune function is a strong defense against invasive pathogens and there is currently no specific antiviral drug against the virus. This article reviews the immunological changes of coronaviruses like SARS, MERS and other viral pneumonia similar to SARS-CoV-2. Combined with the published literature, the potential pathogenesis of COVID-19 is inferred, and the treatment recommendations for giving high-doses intravenous immunoglobulin and low-molecular-weight heparin anticoagulant therapy to severe type patients are proposed.

Title: SARS-CoV-2 pandemic and research gaps: Understanding SARS-CoV-2 interaction with the ACE2 receptor and implications for therapy Content: The COVID-19 pandemic is an emerging threat to global public health. While our current understanding of COVID-19 pathogenesis is limited, a better understanding will help us develop efficacious treatment and prevention strategies for COVID-19. One potential therapeutic target is angiotensin converting enzyme 2 (ACE2). ACE2 primarily catalyzes the conversion of angiotensin I (Ang I) to a nonapeptide angiotensin or the conversion of angiotensin II (Ang II) to angiotensin 1-7 (Ang 1-7) and has direct effects on cardiac function and multiple organs via counter-regulation of the renin-angiotensin system (RAS). Significant to COVID-19, ACE2 is postulated to serve as a major entry receptor for SARS-CoV-2 in human cells, as it does for SARS-CoV. Many infected individuals develop COVID-19 with fever, cough, and shortness of breath that can progress to pneumonia. Disease progression promotes the activation of immune cells, platelets, and coagulation pathways that can lead to multiple organ failure and death. ACE2 is expressed by epithelial cells of the lungs at high level, a major target of the disease, as seen in post-mortem lung tissue of patients who died with COVID-19, which reveals diffuse alveolar damage with cellular fibromyxoid exudates bilaterally. Comparatively, ACE2 is expressed at low level by vascular endothelial cells of the heart and kidney but may also be targeted by the virus in severe COVID-19 cases. Interestingly, SARS-CoV-2 infection downregulates ACE2 expression, which may also play a critical pathogenic role in COVID-19. Importantly, targeting ACE2/Ang 1-7 axis and blocking ACE2 interaction with the S protein of SARS-CoV-2 to curtail SARS-CoV-2 infection are becoming very attractive therapeutics potential for treatment and prevention of COVID-19. Here, we will discuss the following subtopics: 1) ACE2 as a receptor of SARS-CoV-2; 2) clinical and pathological features of COVID-19; 3) role of ACE2 in the infection and pathogenesis of SARS; 4) potential pathogenic role of ACE2 in COVID-19; 5) animal models for pathological studies and therapeutics; and 6) therapeutics development for COVID-19.

Title: Hyperinflammation and derangement of renin-angiotensin-aldosterone system in COVID-19: A novel hypothesis for clinically suspected hypercoagulopathy and microvascular immunothrombosis Content: Early clinical evidence suggests that severe cases of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are frequently characterized by hyperinflammation, imbalance of renin-angiotensin-aldosterone system, and a particular form of vasculopathy, thrombotic microangiopathy, and intravascular coagulopathy. In this paper, we present an immunothrombosis model of COVID-19. We discuss the underlying pathogenesis and the interaction between multiple systems, resulting in propagation of immunothrombosis, which through investigation in the coming weeks, may lead to both an improved understanding of COVID-19 pathophysiology and identification of innovative and efficient therapeutic targets to reverse the otherwise unfavorable clinical outcome of many of these patients.

Title: Why the immune system fails to mount an adaptive immune response to a Covid -19 infection. Content: The Covid-19 pandemic has already affected many thousands of people and has become the greatest health challenge worldwide [1]. The range of clinical presentations varies from asymptomatic and mild clinical symptoms to acute respiratory-distress syndrome (ARDS) and death. Due to the unknown number of asymptomatic viral-shedding and pauci-symptomatic people in the community, the total number of infections is uncertain. As yet, effective treatment is unavailable. However, the results of preliminary studies and clinical trials are improving our understanding of the pathogenesis and treatment of Covid-19. Herein, we share our personal opinions on the immunopathogenesis of this infection.

Title: Inflammatory markers in Covid-19 Patients: a systematic review and meta-analysis. Content: Introduction Diagnosis of COVID-19 is based on clinical manifestation, history of exposure, positive findings on chest CT and laboratory tests. It has been shown that inflammation plays a role in pathogenesis of COVID-19. Method We used the necessary transformations to convert the median and IQR to mean and SD Random-effect model using Der Simonian, and Laird methods was used if heterogeneity between studies was significant, the homogeneity among studies was assessed with I2 Statistic, values above 50%, and for the chi-square test, P-values <0.1 was supposed statistically significant Results Twelve studies were included in the analysis that all of which were conducted in China in the year 2020. The result of combining 12 articles with 772 participants showed that the pooled estimate of the mean of lymphocyte with 95% CI was (Mean: 1.01; 95% CI (0.76-1.26); p-value<0.001). About WBC the pooled result of 9 studies with 402 participants was (Mean: 5.11; 95% CI (3.90-6.32); p-value<0.001) Also the pooled mean estimate of 9 studies with 513 patients for the ratio of Neutrophil/lymphocyte was (Mean: 3.62; 95% CI (1.48-5.77); p-value=0.001). The pooled mean from the combination of 7 studies with 521 patients on CRP was (Mean: 28.75; 95% CI (8.04-49.46). Conclusion Inflammatory Markers increase in patients with Covid-19, which can be a good indicator to find patients.

Title: Potential role of endothelial cell surface ectopic redox complexes in COVID-19 disease pathogenesis Content: The novel coronavirus infectious disease (COVID-19) has rapidly spread and poses a great challenge to researchers, both in elucidating its pathogenic mechanism and developing effective treatments. It has been recently proposed that COVID-19 is an endothelial disease. Indeed, the COVID-19 virus binds to angiotensin-converting enzyme type 2 (ACE2), which is expressed in endothelial cells. ACE2 could be implicated in the production of reactive oxygen species (ROS) caused by endothelial dysfunction due to viral damage. Consequently, oxidative stress could prime these cells to acquire a pro-thrombotic and pro-inflammatory phenotype, predisposing patients to thromboembolic and vasculitic events and to disseminated intravascular coagulopathy (DIC). This implies a pivotal role played by oxygen in the pathogenetic mechanism of COVID-19 disease, in that its availability would tune the oxidant state and consequent damage.

Title: Potential role of endothelial cell surface ectopic redox complexes in COVID-19 disease pathogenesis. Content: The novel coronavirus infectious disease (COVID-19) has rapidly spread and poses a great challenge to researchers, both in elucidating its pathogenic mechanism and developing effective treatments. It has been recently proposed that COVID-19 is an endothelial disease. Indeed, the COVID-19 virus binds to angiotensin-converting enzyme type 2 (ACE2), which is expressed in endothelial cells. ACE2 could be implicated in the production of reactive oxygen species (ROS) caused by endothelial dysfunction due to viral damage. Consequently, oxidative stress could prime these cells to acquire a pro-thrombotic and pro-inflammatory phenotype, predisposing patients to thromboembolic and vasculitic events and to disseminated intravascular coagulopathy (DIC). This implies a pivotal role played by oxygen in the pathogenetic mechanism of COVID-19 disease, in that its availability would tune the oxidant state and consequent damage.

Title: Hyperinflammation and derangement of renin-angiotensin-aldosterone system in COVID-19: A novel hypothesis for clinically suspected hypercoagulopathy and microvascular immunothrombosis Content: Abstract Early clinical evidence suggests that severe cases of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are frequently characterized by hyperinflammation, imbalance of renin-angiotensin-aldosterone system, and a particular form of vasculopathy, thrombotic microangiopathy, and intravascular coagulopathy. In this paper, we present an immunothrombosis model of COVID-19. We discuss the underlying pathogenesis and the interaction between multiple systems, resulting in propagation of immunothrombosis, which through investigation in the coming weeks, may lead to both an improved understanding of COVID-19 pathophysiology and identification of innovative and efficient therapeutic targets to reverse the otherwise unfavorable clinical outcome of many of these patients.

Title: Immunology of COVID-19: current state of the science Content: Abstract The coronavirus disease 2019 (COVID-19) pandemic, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has affected millions of people worldwide, igniting an unprecedented effort from the scientific community to understand the biological underpinning of COVID19 pathophysiology. In this review, we summarize the current state of knowledge of innate and adaptive immune responses elicited by SARS-CoV-2 infection and the immunological pathways that likely contribute to disease severity and death. We also discuss the rationale and clinical outcome of current therapeutic strategies as well as prospective clinical trials to prevent or treat SARS-CoV-2 infection.

Title: Immunology of COVID-19: Current State of the Science Content: The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has affected millions of people worldwide, igniting an unprecedented effort from the scientific community to understand the biological underpinning of COVID19 pathophysiology. In this Review, we summarize the current state of knowledge of innate and adaptive immune responses elicited by SARS-CoV-2 infection and the immunological pathways that likely contribute to disease severity and death. We also discuss the rationale and clinical outcome of current therapeutic strategies as well as prospective clinical trials to prevent or treat SARS-CoV-2 infection.

Title: Induction of pro-inflammatory cytokines (IL-1 and IL-6) and lung inflammation by COVID-19: anti-inflammatory strategies Content: COVID-19 (coronavirus disease-19) involves humans as well as animals and may cause serious damage to the respiratory tract including the lung This pathogenic virus has been identified in swabs performed on the throat and nose of patients who suffer from or are suspected of the disease When COVID-19 infect the upper and lower respiratory tract it can cause mild or highly acute respiratory syndrome with consequent release of pro-inflammatory cytokines, including interleukin (IL)-1b and IL-6 The binding of COVID-19 to the Toll Like Receptor (TLR) causes the release of pro-IL-1b which is cleaved by caspase-1, followed by inflammasome activation and production of active mature IL-1b which is a mediator of lung inflammation, fever and fibrosis Suppression of pro-inflammatory IL-1 family members and IL-6 have been shown to have a therapeutic effect in many inflammatory diseases, including viral infections Cytokine IL-37 has the ability to suppress innate and acquired immune response and also has the capacity to inhibit inflammation by acting on IL-18Ra receptor IL-37 performs its immunosuppressive activity by acting on mTOR and increasing the adenosine monophosphate (AMP) kinase This cytokine inhibits class II histocompatibility complex (MHC) molecules and inflammation in inflammatory diseases by suppressing MyD88 and subsequently IL-1β, IL-6, TNF and CCL2 The suppression of IL-1b by IL-37 in inflammatory state induced by COVID-19 can have a new therapeutic effect previously unknown Another inhibitory cytokine is IL-38, the newest cytokine of the IL-1 family members, produced by several immune cells including B cells and macrophages IL-38 is also a suppressor cytokine which inhibits IL-1b and other pro-inflammatory IL-family members IL-38 is a potential therapeutic cytokine which inhibits inflammation in viral infections including that caused by COVID-19, providing a new relevant strategy

Title: SARS-CoV-2 COVID-19 susceptibility and lung inflammatory storm by smoking and vaping Content: The current pandemic of COVID-19 has caused severe morbidity and mortality across the globe. People with a smoking history have severe disease outcomes by COVID-19 infection. Epidemiological studies show that old age and pre-existing disease conditions (hypertension and diabetes) result in severe disease outcome and mortality amongst COVID-19 patients. Evidences suggest that the S1 domain of the SARS-CoV-2 (causative agent of COVID-19) membrane spike has a high affinity towards the angiotensin-converting enzyme 2 (ACE2) receptor found on the host’s lung epithelium. Likewise, TMPRSS2 protease has been shown to be crucial for viral activation thus facilitating the viral engulfment. The viral entry has been shown to cause ‘cytokine storm’ involving excessive production of pro-inflammatory cytokines/chemokines including IL-6, TNF-α, IFN-γ, IL-2, IL-7, IP-10, MCP-3 or GM-CSF, which is augmented by smoking. Future research could target these inflammatory-immunological responses to develop effective therapy for COVID-19. This mini-review provides a consolidated account on the role of inflammation and immune responses, proteases, and epithelial permeability by smoking and vaping during SARS-CoV2 infection with future directions of research, and provides a list of the potential targets for therapies particularly controlling cytokine storms in the lung.

Title: Distinct infection process of SARS-CoV-2 in human bronchial epithelial cells line Content: COVID-19, caused by SARS-CoV-2, leads to a series of clinical symptoms of respiratory and pulmonary inflammatory reactions via unknown pathologic mechanisms related to the viral infection process in tracheal or bronchial epithelial cells. Investigation of this viral infection in the human bronchial epithelial cell line (16HBE) suggests that SARS-CoV-2 can enter these cells through interaction between its membrane-localized S protein with the ACE2 molecule on the host cell membrane. Further observation indicates distinct viral replication with a dynamic and moderate increase, whereby viral replication does not lead to a specific cytopathic effect but maintains a continuous release of progeny virions from infected cells. Although mRNA expression of various innate immune signaling molecules is altered in the cells, transcription of IFNα, IFNß and IFNÎ³ is unchanged. Furthermore, expression of some interleukins related to inflammatory reactions, such as IL-6, IL-2 and IL-8, is maintained at low levels, whereas that of interleukins involved in immune regulation is upregulated. Interestingly, IL-22, an interleukin that functions mainly in tissue repair, shows very high expression. Collectively, these data suggest a distinct infection process for this virus in respiratory epithelial cells, which may be linked to its clinicopathological mechanism. This article is protected by copyright. All rights reserved.

Title: Immunopathology and immunotherapeutic strategies in severe acute respiratory syndrome coronavirus 2 infection. Content: The outbreak of coronavirus disease 2019 (COVID-19) and pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a major concern globally. As of 14 April 2020, more than 1.9 million COVID-19 cases have been reported in 185 countries. Some patients with COVID-19 develop severe clinical manifestations, while others show mild symptoms, suggesting that dysregulation of the host immune response contributes to disease progression and severity. In this review, we have summarized and discussed recent immunological studies focusing on the response of the host immune system and the immunopathology of SARS-CoV-2 infection as well as immunotherapeutic strategies for COVID-19. Immune evasion by SARS-CoV-2, functional exhaustion of lymphocytes, and cytokine storm have been discussed as part of immunopathology mechanisms in SARS-CoV-2 infection. Some potential immunotherapeutic strategies to control the progression of COVID-19, such as passive antibody therapy and use of interferon αβ and IL-6 receptor (IL-6R) inhibitor, have also been discussed. This may help us to understand the immune status of patients with COVID-19, particularly those with severe clinical presentation, and form a basis for further immunotherapeutic investigations.

Title: Transcriptomic profiling of disease severity in patients with COVID-19 reveals role of blood clotting and vasculature related genes Content: COVID-19 caused by SARS-CoV-2 manifests as a range of symptoms. Understanding the molecular mechanisms responsible for immuno-pathogenesis of disease is important for treatment and management of COVID-19. We examined host transcriptomes in moderate and severe COVID-19 cases with a view to identifying pathways that affect its progression. RNA extracted from whole blood of COVID-19 cases was analysed by microarray analysis. Moderate and severe cases were compared with healthy controls and differentially regulated genes (DEGs) categorized into cellular pathways. DEGs in COVID-19 cases were mostly related to host immune activation and cytokine signaling, pathogen uptake, host defenses, blood and vasculature genes, and SARS-CoV-2- and other virus- affected pathways. The DEGs in these pathways were increased in severe compared with moderate cases. In a severe COVID-19 patient with an unfavourable outcome we observed dysregulation of genes in platelet homeostasis and cardiac conduction and fibrin clotting with disease progression.

Title: The pathogenesis and treatment of the `Cytokine Storm' in COVID-19 Content: Summary Cytokine storm is an excessive immune response to external stimuli. The pathogenesis of the cytokine storm is complex. The disease progresses rapidly, and the mortality is high. Certain evidence shows that, during the coronavirus disease 2019 (COVID-19) epidemic, the severe deterioration of some patients has been closely related to the cytokine storm in their bodies. This article reviews the occurrence mechanism and treatment strategies of the COVID-19 virus-induced inflammatory storm in attempt to provide valuable medication guidance for clinical treatment.

Title: Should we stimulate or suppress immune responses in COVID-19? Cytokine and anti-cytokine interventions Content: The coronavirus disease-19 pandemic (COVID-19), which appeared in China in December 2019 and rapidly spread throughout the world, has forced clinicians and scientists to take up extraordinary challenges. This unprecedented situation led to the inception of numerous fundamental research protocols and many clinical trials. It quickly became apparent that although COVID-19, in the vast majority of cases, was a benign disease, it could also develop a severe form with sometimes fatal outcomes. Cytokines are central to the pathophysiology of COVID-19; while some of them are beneficial (type-I interferon, interleukin-7), others appear detrimental (interleukin-1ß, -6, and TNF-α) particularly in the context of the so-called cytokine storm. Yet another characteristic of the disease has emerged: concomitant immunodeficiency, notably involving impaired type-I interferon response, and lymphopenia. This review provides an overview of current knowledge on COVID-19 immunopathology. We discuss the defective type-I IFN response, the theoretical role of IL-7 to restore lymphocyte repertoire, as well as we mention the two patterns observed in severe COVID-19 (i.e. interleukin-1ß-driven macrophage activation syndrome vs. interleukin-6-driven immune dysregulation). Next, reviewing current evidence drawn from clinical trials, we examine a number of cytokine and anti-cytokine therapies, including interleukin-1, -6, and TNF inhibitors, as well as less targeted therapies, such as corticosteroids, chloroquine, or JAK inhibitors.

Title: Histopathology and genetic susceptibility in COVID‐19 pneumonia Content: The clinical features of COVID‐19 range from a mild illness to patients with a very severe illness with acute hypoxemic respiratory failure requiring ventilation and Intensive Care Unit admission. Risk factors for a fatal disease include older age, respiratory disease, diabetes mellitus, obesity and hypertension. Little is known about the mechanisms behind observed episodes of sudden deterioration or the infrequent idiosyncratic clinical demise in otherwise healthy and young subjects. As in other diseases, the answer to some of these questions may in time be provided by genotyping as well careful clinical, serological, radiological and histopathological phenotyping, which enable mechanistic insights into the differences in pathogenesis and underlying immunological and tissue regenerative response patterns. We will aim to provide a brief overview of the existing evidence for such differences in host response and outcome, and generate hypotheses for divergent patterns and avenues for future research, by highlighting similarities and differences in histopathological appearance between COVID19 and influenza as well as previous coronavirus outbreaks, and by discussing predisposition through genetics and underlying disease.

Title: Immune Response, Inflammation, and the Clinical Spectrum of COVID-19 Content: The current COVID-19 pandemic began in December 2019 in Wuhan (China) and rapidly extended to become a global sanitary and economic emergency. Its etiological agent is the coronavirus SARS-CoV-2. COVID-19 presents a wide spectrum of clinical manifestations, which ranges from an asymptomatic infection to a severe pneumonia accompanied by multisystemic failure that can lead to a patient's death. The immune response to SARS-CoV-2 is known to involve all the components of the immune system that together appear responsible for viral elimination and recovery from the infection. Nonetheless, such immune responses are implicated in the disease's progression to a more severe and lethal process. This review describes the general aspects of both COVID-19 and its etiological agent SARS-CoV-2, stressing the similarities with other severe coronavirus infections, such as SARS and MERS, but more importantly, pointing toward the evidence supporting the hypothesis that the clinical spectrum of COVID-19 is a consequence of the corresponding variable spectrum of the immune responses to the virus. The critical point where progression of the disease ensues appears to center on loss of the immune regulation between protective and altered responses due to exacerbation of the inflammatory components. Finally, it appears possible to delineate certain major challenges deserving of exhaustive investigation to further understand COVID-19 immunopathogenesis, thus helping to design more effective diagnostic, therapeutic, and prophylactic strategies.

Title: Dysregulation of the immune system as a driver of the critical course of the novel coronavirus disease 2019 Content: Novel coronavirus disease-2019 (COVID-19) is a highly contagious respiratory-related disease induced by the newly emerged virus SARS-CoV-2. Given that inflammatory immune cells may induce severe lung injury, the involvement of immune factors in the pathogenesis of the disease cannot be overestimated. It has been demonstrated that coronaviruses (CoVs) have developed mechanisms of immune evasion, making them invisible to the immune system at an early stage of infection. The mechanism relies on inhibition of the anti-viral response of type I interferons (IFNs), which supports uncontrolled viral replication in epithelial cells. There is growing body of evidence that the fatal hyperinflammation ('cytokine storm') responsible for the severe course of COVID-19 is a consequence of massive SARS-CoV-2 replication rather than inappropriate hyperresponsiveness of the immune system. Therefore, a dampened innate anti-viral immune response seems to be the primary cause of the delayed critical cascade of uncontrolled immune events leading to fulminating systemic inflammation. The occurrence of virus transmission even in asymptomatic subjects infected with SARS-CoV-2 clearly strengthens the evidence for a key role of sufficient immune control of viral replication in a subset of cases (e.g. in children, a population with highly effective innate immune responses). Although administration of immunomodulatory therapeutics is recommended under certain conditions in the guidelines of COVID-19 management, controversies regarding treatment protocols in immunocompromised patients infected with SARS-CoV-2 still exist. Extended knowledge of clinicians on the dysregulated immune response, which is a driver of the COVID-19 outcome, may improve both therapeutic protocols and the prognosis of SARS-CoV-2 infected patients.

Title: Dysregulation of the immune system as a driver of the critical course of the novel coronavirus disease 2019. Content: Novel coronavirus disease-2019 (COVID-19) is a highly contagious respiratory-related disease induced by the newly emerged virus SARS-CoV-2. Given that inflammatory immune cells may induce severe lung injury, the involvement of immune factors in the pathogenesis of the disease cannot be overestimated. It has been demonstrated that coronaviruses (CoVs) have developed mechanisms of immune evasion, making them invisible to the immune system at an early stage of infection. The mechanism relies on inhibition of the anti-viral response of type I interferons (IFNs), which supports uncontrolled viral replication in epithelial cells. There is growing body of evidence that the fatal hyperinflammation ('cytokine storm') responsible for the severe course of COVID-19 is a consequence of massive SARS-CoV-2 replication rather than inappropriate hyperresponsiveness of the immune system. Therefore, a dampened innate anti-viral immune response seems to be the primary cause of the delayed critical cascade of uncontrolled immune events leading to fulminating systemic inflammation. The occurrence of virus transmission even in asymptomatic subjects infected with SARS-CoV-2 clearly strengthens the evidence for a key role of sufficient immune control of viral replication in a subset of cases (e.g. in children, a population with highly effective innate immune responses). Although administration of immunomodulatory therapeutics is recommended under certain conditions in the guidelines of COVID-19 management, controversies regarding treatment protocols in immunocompromised patients infected with SARS-CoV-2 still exist. Extended knowledge of clinicians on the dysregulated immune response, which is a driver of the COVID-19 outcome, may improve both therapeutic protocols and the prognosis of SARS-CoV-2 infected patients.

Title: COVID-19 for the Cardiologist: A Current Review of the Virology, Clinical Epidemiology, Cardiac and Other Clinical Manifestations and Potential Therapeutic Strategies Content: The coronavirus disease-2019 (COVID-19), a contagious disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV2), has reached pandemic status. As it spreads across the world, it has overwhelmed healthcare systems, strangled the global economy and led to a devastating loss of life. Widespread efforts from regulators, clinicians and scientists are driving a rapid expansion of knowledge of the SARS-CoV2 virus and the COVID-19 disease. We review the most current data with a focus on our basic understanding of the mechanism(s) of disease and translation to the clinical syndrome and potential therapeutics. We discuss the basic virology, epidemiology, clinical manifestation, multi-organ consequences, and outcomes. With a focus on cardiovascular complications, we propose several mechanisms of injury. The virology and potential mechanism of injury form the basis for a discussion of potential disease-modifying therapies.

Title: Coronavirus Disease 2019-related dyspnea cases difficult to interpret using chest computed tomography Content: Patients with Coronavirus Disease 2019 (COVID-19) often have clinical characteristics, such as chest tightness and dyspnea. Continuous, unresolved dyspnea often indicates the progression of lung lesions. The mechanism that underlies the chest distress and dyspnea in patients with COVID-19 is still unclear. Chest CT has a higher sensitivity and can play an essential role in the diagnosis and treatment of the disease. However, our clinical observations showed that although some patients had significant chest distress and dyspnea, the lesions that were observed in the lungs during computed tomography were milder and not completely consistent with clinical symptoms. We analyzed the clinical characteristics, laboratory test results, and imaging findings of these patients. We found that extensive inflammation of the bilateral and respiratory bronchioles in patients with COVID-19 due to excessive activation of proinflammatory cytokines and chemotactic aggregation of T-lymphocytes at the site of inflammation are possible mechanisms underlying chest distress and dyspnea in patients with COVID-19. Short-time and lose-dose use of corticosteroid may be helpful to treat chest tightness and dyspnea in mild COVID-19 patients. Through this study, we aimed to improve our understanding of the pathogenesis of COVID-19.

Title: Insights into the Use of C-Reactive Protein as a Diagnostic Index of Disease Severity in COVID-19 Infections Content: Approximately 20% of patients infected with SARS-CoV-2 (COVID-19) develop potentially life-threatening pathologies involving hyperinflammation, cytokine storm, septic shock complications, coagulation dysfunction, and multiple organ failure. Blood levels of the prototypic acute phase reactant, C-reactive protein (CRP), which is hepatically synthesized and released in response to interleukin-6 stimulation, is markedly elevated in patients with COVID-19. Markedly high CRP levels correlate with poor prognosis for survival. Insights into CRP structure-function relationships have uncovered both pro- and anti-inflammatory isoforms that may be used to monitor the extent of tissue damage associated with COVID-19 pathologies and prognoses. Herein, rationale is given for interpretation of CRP blood levels as a simple, rapid, and cost-effective way to assess disease severity and help guide therapeutic options in COVID-19 patients.

Title: Insights into the Use of C-Reactive Protein as a Diagnostic Index of Disease Severity in COVID-19 Infections. Content: Approximately 20% of patients infected with SARS-CoV-2 (COVID-19) develop potentially life-threatening pathologies involving hyperinflammation, cytokine storm, septic shock complications, coagulation dysfunction, and multiple organ failure. Blood levels of the prototypic acute phase reactant, C-reactive protein (CRP), which is hepatically synthesized and released in response to interleukin-6 stimulation, is markedly elevated in patients with COVID-19. Markedly high CRP levels correlate with poor prognosis for survival. Insights into CRP structure-function relationships have uncovered both pro- and anti-inflammatory isoforms that may be used to monitor the extent of tissue damage associated with COVID-19 pathologies and prognoses. Herein, rationale is given for interpretation of CRP blood levels as a simple, rapid, and cost-effective way to assess disease severity and help guide therapeutic options in COVID-19 patients.

Title: Immune response in COVID-19: addressing a pharmacological challenge by targeting pathways triggered by SARS-CoV-2 Content: To date, no vaccines or effective drugs have been approved to prevent or treat COVID-19 and the current standard care relies on supportive treatments. Therefore, based on the fast and global spread of the virus, urgent investigations are warranted in order to develop preventive and therapeutic drugs. In this regard, treatments addressing the immunopathology of SARS-CoV-2 infection have become a major focus. Notably, while a rapid and well-coordinated immune response represents the first line of defense against viral infection, excessive inflammatory innate response and impaired adaptive host immune defense may lead to tissue damage both at the site of virus entry and at systemic level. Several studies highlight relevant changes occurring both in innate and adaptive immune system in COVID-19 patients. In particular, the massive cytokine and chemokine release, the so-called “cytokine storm”, clearly reflects a widespread uncontrolled dysregulation of the host immune defense. Although the prospective of counteracting cytokine storm is compelling, a major limitation relies on the limited understanding of the immune signaling pathways triggered by SARS-CoV-2 infection. The identification of signaling pathways altered during viral infections may help to unravel the most relevant molecular cascades implicated in biological processes mediating viral infections and to unveil key molecular players that may be targeted. Thus, given the key role of the immune system in COVID-19, a deeper understanding of the mechanism behind the immune dysregulation might give us clues for the clinical management of the severe cases and for preventing the transition from mild to severe stages.

Title: The bio-mission of interleukin-6 in the pathogenesis of COVID-19: A brief look at potential therapeutic tactics Content: Interleukin-6 (IL-6), known as an inflammatory cytokine, can be involved in many innate and adaptive immune responses. The role of IL-6 in the pathogenesis of the novel coronavirus disease 2019 (COVID-19) has recently received much more attention due to the spread of the virus and its pandemic potential. Cytokine storm is among the most critical pathological events in patients affected with coronaviruses (CoVs), i.e., severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV), and COVID-19, causing inflammation-induced lung injury and also occurring as a result of dysregulation of immune responses to the mentioned viruses. IL-6, along with some other inflammatory cytokines, including IL-1 beta (β), IL-8, and tumor necrosis factor-alpha (TNF-α), as well as inflammatory chemokines, can significantly contribute to, fever, lymphopenia, coagulation, lung injury, and multi-organ failure (MOF). Therefore, researchers are to explore novel approaches to treat the disease through targeting of IL-6 and its receptors based on prior experience of other disorders. In this review article, the latest findings on the role of IL-6 in the pathogenesis of COVID-19, as well as therapeutic perspectives, were summarized and discussed.

Title: Coronavirus Disease 2019 and Stroke: Clinical Manifestations and Pathophysiological Insights Content: Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global health threat. Some COVID-19 patients have exhibited widespread neurological manifestations including stroke. Acute ischemic stroke, intracerebral hemorrhage, and cerebral venous sinus thrombosis have been reported in patients with COVID-19. COVID-19-associated coagulopathy is increasingly recognized as a result of acute infection and is likely caused by inflammation, including inflammatory cytokine storm. Recent studies suggest axonal transport of SARS-CoV-2 to the brain can occur via the cribriform plate adjacent to the olfactory bulb that may lead to symptomatic anosmia. The internalization of SARS-CoV-2 is mediated by the binding of the spike glycoprotein of the virus to the angiotensin-converting enzyme 2 (ACE2) on cellular membranes. ACE2 is expressed in several tissues including lung alveolar cells, gastrointestinal tissue, and brain. The aim of this review is to provide insights into the pathophysiological stroke mechanisms in COVID-19 patients. SARS-CoV-2 can down-regulate ACE2 and, in turn, over-activate the classical renin-angiotensin system (RAS) axis and decrease the activation of the alternative RAS pathway in the brain. The consequent imbalance in vasodilation, neuroinflammation, oxidative stress, and thrombotic response may contribute to the pathophysiology of stroke during SARS-CoV-2 infection.

Title: Immunological and inflammatory profiles in mild and severe cases of COVID-19 Content: COVID-19 is associated with 5.1% mortality. Although the virological, epidemiological, clinical, and management outcome features of COVID-19 patients have been defined rapidly, the inflammatory and immune profiles require definition as they influence pathogenesis and clinical expression of COVID-19. Here we show lymphopenia, selective loss of CD4+ T cells, CD8+ T cells and NK cells, excessive T-cell activation and high expression of T-cell inhibitory molecules are more prominent in severe cases than in those with mild disease. CD8+ T cells in patients with severe disease express high levels of cytotoxic molecules. Histochemical studies of lung tissue from one fatality show sub-anatomical distributions of SARS-CoV-2 RNA and massive infiltration of T cells and macrophages. Thus, aberrant activation and dysregulation of CD8+ T cells occur in patients with severe COVID-19 disease, an effect that might be for pathogenesis of SARS-CoV-2 infection and indicate that immune-based targets for therapeutic interventions constitute a promising treatment for severe COVID-19 patients.

Title: Neutrophils and Neutrophil Extracellular Traps Drive Necroinflammation in COVID-19 Content: The COVID-19 pandemic is progressing worldwide with an alarming death toll. There is an urgent need for novel therapeutic strategies to combat potentially fatal complications. Distinctive clinical features of severe COVID-19 include acute respiratory distress syndrome, neutrophilia, and cytokine storm, along with severe inflammatory response syndrome or sepsis. Here, we propose the putative role of enhanced neutrophil infiltration and the release of neutrophil extracellular traps, complement activation and vascular thrombosis during necroinflammation in COVID-19. Furthermore, we discuss how neutrophilic inflammation contributes to the higher mortality of COVID-19 in patients with underlying co-morbidities such as diabetes and cardiovascular diseases. This perspective highlights neutrophils as a putative target for the immunopathologic complications of severely ill COVID-19 patients. Development of the novel therapeutic strategies targeting neutrophils may help reduce the overall disease fatality rate of COVID-19.

Title: Neutrophils and Neutrophil Extracellular Traps Drive Necroinflammation in COVID-19. Content: The COVID-19 pandemic is progressing worldwide with an alarming death toll. There is an urgent need for novel therapeutic strategies to combat potentially fatal complications. Distinctive clinical features of severe COVID-19 include acute respiratory distress syndrome, neutrophilia, and cytokine storm, along with severe inflammatory response syndrome or sepsis. Here, we propose the putative role of enhanced neutrophil infiltration and the release of neutrophil extracellular traps, complement activation and vascular thrombosis during necroinflammation in COVID-19. Furthermore, we discuss how neutrophilic inflammation contributes to the higher mortality of COVID-19 in patients with underlying co-morbidities such as diabetes and cardiovascular diseases. This perspective highlights neutrophils as a putative target for the immunopathologic complications of severely ill COVID-19 patients. Development of the novel therapeutic strategies targeting neutrophils may help reduce the overall disease fatality rate of COVID-19.

Title: [From SARS to COVID-19: pathogens, receptor, pathogenesis and principles of the treatment]. Content: COVID-19 is an infectious disease caused by 2019-nCoV and characterizes as an atypical pneumonia. Since 2019-nCoV is a newly emerging virus, the pathogenesis of COVID-19 is not well known. Most patients had a self-limited course, and some became severe even death. In this review, the authors compared two coronavirus outbreaks during the past two decades: the SARS-CoV and 2019-nCoV. Among the biological nature of the pathogens, viral receptor distribution on the human cells, and the pathological findings in the targeted organs and clinical features of the patients with the diseases, found similarities and differences between the two diseases. Due to the shared receptor ACE2 and the pathological similarities of the SARS-CoV and 2019-nCoV diseases. They proposed a pathogenesis model for COVID-19. Like the SARS-CoV disease, COVID-19 is a systematic disease and targets the lungs, vasculatures, and the immune system. The basic pathogenesis involves two interlinked processes: a severe lung inflammation and immune deficiency, both of which are related to an inappropriate immune response and over-production of cytokines. Thus, treatment approaches should include antiviral and anti-proinflammatory cytokines, anti-infectious and life support therapies, especially in patients with severe diseases.

Title: [From SARS to COVID-19: pathogens, receptor, pathogenesis and principles of the treatment] Content: COVID-19 is an infectious disease caused by 2019-nCoV and characterizes as an atypical pneumonia. Since 2019-nCoV is a newly emerging virus, the pathogenesis of COVID-19 is not well known. Most patients had a self-limited course, and some became severe even death. In this review, the authors compared two coronavirus outbreaks during the past two decades: the SARS-CoV and 2019-nCoV. Among the biological nature of the pathogens, viral receptor distribution on the human cells, and the pathological findings in the targeted organs and clinical features of the patients with the diseases, found similarities and differences between the two diseases had been found. Due to the shared receptor ACE2 and the pathological similarities of the SARS-CoV and 2019-nCoV diseases,authors proposed a pathogenesis model for COVID-19. Like the SARS-CoV disease, COVID-19 is a systematic disease and targets the lungs, vasculatures, and the immune system. The basic pathogenesis involves two interlinked processes: a severe lung inflammation and immune deficiency, both of which were related to an inappropriate immune response and over-production of cytokines. Thus, treatment approaches should include antiviral and anti-proinflammatory cytokines, anti-infectious and life support therapies, especially in patients with severe diseases.

Title: Potential pathophysiological mechanisms leading to increased COVID-19 susceptibility and severity in obesity Content: As we are facing worldwide pandemic of COVID-19, we aimed to identify potential pathophysiological mechanisms leading to increased COVID-19 susceptibility and severity in obesity. Special emphasis will be given on increased susceptibility to infections due to obesity-related low-grade chronic inflammation, higher expression of angiotensin converting enzyme-2 and pathway-associated components, as well as decreased vitamin D bioavailability, since all of them provide easier ways for the virus to enter into host cells, replicate and stunt adequate immune responses.

Title: Immunopathology and immunotherapeutic strategies in severe acute respiratory syndrome coronavirus 2 infection Content: The outbreak of coronavirus disease 2019 (COVID-19) and pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a major concern globally. As of 14 April 2020, more than 1.9 million COVID-19 cases have been reported in 185 countries. Some patients with COVID-19 develop severe clinical manifestations, while others show mild symptoms, suggesting that dysregulation of the host immune response contributes to disease progression and severity. In this review, we have summarized and discussed recent immunological studies focusing on the response of the host immune system and the immunopathology of SARS-CoV-2 infection as well as immunotherapeutic strategies for COVID-19. Immune evasion by SARS-CoV-2, functional exhaustion of lymphocytes, and cytokine storm have been discussed as part of immunopathology mechanisms in SARS-CoV-2 infection. Some potential immunotherapeutic strategies to control the progression of COVID-19, such as passive antibody therapy and use of interferon αß and IL-6 receptor (IL-6R) inhibitor, have also been discussed. This may help us to understand the immune status of patients with COVID-19, particularly those with severe clinical presentation, and form a basis for further immunotherapeutic investigations.

Title: Recent Insight into SARS-CoV2 Immunopathology and Rationale for Potential Treatment and Preventive Strategies in COVID-19 Content: As the outbreak of the new coronavirus (SARS-CoV-2) infection is spreading globally, great effort is being made to understand the disease pathogenesis and host factors that predispose to disease progression in an attempt to find a window of opportunity for intervention. In addition to the direct cytopathic effect of the virus, the host hyper-inflammatory response has emerged as a key factor in determining disease severity and mortality. Accumulating clinical observations raised hypotheses to explain why some patients develop more severe disease while others only manifest mild or no symptoms. So far, Covid-19 management remains mainly supportive. However, many researches are underway to clarify the role of antiviral and immunomodulating drugs in changing morbidity and mortality in patients who become severely ill. This review summarizes the current state of knowledge on the interaction between SARS-CoV-2 and the host immune system and discusses recent findings on proposed pharmacologic treatments.

Title: The innate immune system: fighting on the front lines or fanning the flames of COVID-19? Content: Abstract The coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 has had devastating global impacts and will continue to have dramatic effects on public health for years to come. A better understanding of the immune response to SARS-CoV-2 will be critical for the application and development of therapeutics. The degree to which the innate immune response confers protection or induces pathogenesis through a dysregulated immune response remains unclear. In this review, we discuss what is known about the role of the innate immune system during SARS-CoV-2 infection, suggest directions for future studies, and evaluate proposed COVID-19 immunomodulating therapeutics.

Title: The cytokine storm and COVID-19 Content: Coronavirus disease 2019 (COVID-19), which began in Wuhan, China in December 2019 has caused a large global pandemic and poses a serious threat to public health. More than four million cases of COVID-19, which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have been confirmed as of May 11, 2020. SARS-CoV-2 is a highly pathogenic and transmissible coronavirus that primarily spreads through respiratory droplets and close contact. A growing body of clinical data suggests that a cytokine storm is associated with COVID-19 severity and is also a crucial cause of death from COVID-19. In the absence of antivirals and vaccines for COVID-19, there is an urgent need to understand the cytokine storm in COVID-19. Here, we have reviewed the current understanding of the features of SARS-CoV-2 and the pathological features, pathophysiological mechanisms, and treatments of the cytokine storm induced by COVID-19. Additionally, we suggest that the identification and treatment of the cytokine storm are important components for rescuing patients with severe COVID-19. This article is protected by copyright. All rights reserved.

Title: Immunologic aspects of characteristics, diagnosis, and treatment of coronavirus disease 2019 (COVID-19) Content: On March 11, 2020, the World Health Organization declared the worldwide spread of the infectious disease COVID-19, caused by a new strain of coronavirus, SARS-CoV-2, as a pandemic. Like in all other infectious diseases, the host immune system plays a key role in our defense against SARS-CoV-2 infection. However, viruses are able to evade the immune attack and proliferate and, in susceptible individuals, cause severe inflammatory response known as cytokine storm, particularly in the lungs. The advancement in our understanding of the mechanisms underlying the host immune responses promises to facilitate the development of approaches for prevention or treatment of diseases. Components of immune system, such as antibodies, can also be used to develop sensitive and specific diagnostic methods as well as novel therapeutic agents. In this review, we summarize our knowledge about how the host mounts immune responses to infection by SARS-CoV-2. We also describe the diagnostic methods being used for COVID-19 identification and summarize the current status of various therapeutic strategies, including vaccination, being considered for treatment of the disease.

Title: Functional characterization of SARS-CoV-2 infection suggests a complex inflammatory response and metabolic alterations Content: Covid-19, caused by the SARS-CoV-2 virus, has reached the category of a worldwide pandemic. Even though intensive efforts, no effective treatments or a vaccine are available. Molecular characterization of the transcriptional response in Covid-19 patients could be helpful to identify therapeutic targets. In this study, RNAseq data from peripheral blood mononuclear cell samples from Covid-19 patients and healthy controls was analyzed from a functional point of view using probabilistic graphical models. Two networks were built: one based on genes differentially expressed between healthy and infected individuals and another one based on the 2,000 most variable genes in terms of expression in order to make a functional characterization. In the network based on differentially expressed genes, two inflammatory response nodes with different tendencies were identified, one related to cytokines and chemokines, and another one related to bacterial infections. In addition, differences in metabolism, which were studied in depth using Flux Balance Analysis, were identified. SARS-CoV2-infection caused alterations in glutamate, methionine and cysteine, and tetrahydrobiopterin metabolism. In the network based on 2,000 most variable genes, also two inflammatory nodes with different tendencies between healthy individuals and patients were identified. Similar to the other network, one was related to cytokines and chemokines. However, the other one, lower in Covid-19 patients, was related to allergic processes and self-regulation of the immune response. Also, we identified a decrease in T cell node activity and an increase in cell division node activity. In the current absence of treatments for these patients, functional characterization of the transcriptional response to SARS-CoV-2 infection could be helpful to define targetable processes. Therefore, these results may be relevant to propose new treatments. Author Summary SARS-CoV-2 infection caused Covid-19 which has reached the category of a worldwide pandemic. However, no treatments or vaccines are still available. For this reason, it is still necessary the molecular study of this disease. In this study, we reanalyzed data from peripheral blood mononuclear cells from Covid-19 patients and healthy controls using computational techniques that allow the study of differential biological processes and metabolic pathways. The results suggested a complex inflammatory response, involving genes related to response to bacterial infection and allergic processes, and alterations in metabolic pathways such as glutamate metabolism, cysteine and methionine metabolism or tetrahydrobiopterin metabolism. These processes could be used in the future as therapeutic targets in Covi-19 infection.

Title: The Innate Immune System: Fighting on the Front Lines or Fanning the Flames of COVID-19? Content: The coronavirus disease 2019 (COVID-19) pandemic caused by SARS-CoV-2 has had devastating global impacts and will continue to have dramatic effects on public health for years to come. A better understanding of the immune response to SARS-CoV-2 will be critical for the application and development of therapeutics. The degree to which the innate immune response confers protection or induces pathogenesis through a dysregulated immune response remains unclear. In this review, we discuss what is known about the role of the innate immune system during SARS-CoV-2 infection, suggest directions for future studies, and evaluate proposed COVID-19 immunomodulating therapeutics.

Title: Immune response in COVID-19: addressing a pharmacological challenge by targeting pathways triggered by SARS-CoV-2 Content: To date, no vaccines or effective drugs have been approved to prevent or treat COVID-19 and the current standard care relies on supportive treatments. Therefore, based on the fast and global spread of the virus, urgent investigations are warranted in order to develop preventive and therapeutic drugs. In this regard, treatments addressing the immunopathology of SARS-CoV-2 infection have become a major focus. Notably, while a rapid and well-coordinated immune response represents the first line of defense against viral infection, excessive inflammatory innate response and impaired adaptive host immune defense may lead to tissue damage both at the site of virus entry and at systemic level. Several studies highlight relevant changes occurring both in innate and adaptive immune system in COVID-19 patients. In particular, the massive cytokine and chemokine release, the so-called "cytokine storm", clearly reflects a widespread uncontrolled dysregulation of the host immune defense. Although the prospective of counteracting cytokine storm is compelling, a major limitation relies on the limited understanding of the immune signaling pathways triggered by SARS-CoV-2 infection. The identification of signaling pathways altered during viral infections may help to unravel the most relevant molecular cascades implicated in biological processes mediating viral infections and to unveil key molecular players that may be targeted. Thus, given the key role of the immune system in COVID-19, a deeper understanding of the mechanism behind the immune dysregulation might give us clues for the clinical management of the severe cases and for preventing the transition from mild to severe stages.

Title: The pathogenesis and treatment of the `Cytokine Storm' in COVID-19 Content: Cytokine storm is an excessive immune response to external stimuli. The pathogenesis of the cytokine storm is complex. The disease progresses rapidly, and the mortality is high. Certain evidence shows that, during the coronavirus disease 2019 (COVID-19) epidemic, the severe deterioration of some patients has been closely related to the cytokine storm in their bodies. This article reviews the occurrence mechanism and treatment strategies of the COVID-19 virus-induced inflammatory storm in attempt to provide valuable medication guidance for clinical treatment.

Title: Rationale for targeting complement in COVID-19 Content: A novel coronavirus, SARS-CoV-2, has recently emerged in China and spread internationally, posing a health emergency to the global community. COVID-19 caused by SARS-CoV-2 is associated with an acute respiratory illness that varies from mild to the life-threatening acute respiratory distress syndrome (ARDS). The complement system is part of the innate immune arsenal against pathogens, in which many viruses can evade or employ to mediate cell entry. The immunopathology and acute lung injury orchestrated through the influx of pro-inflammatory macrophages and neutrophils can be directly activated by complement components to prime an overzealous cytokine storm. The manifestations of severe COVID-19 such as the ARDS, sepsis and multiorgan failure have an established relationship with activation of the complement cascade. We have collected evidence from all the current studies we are aware of on SARS-CoV-2 immunopathogenesis and the preceding literature on SARS-CoV-1 and MERS-CoV infection linking severe COVID-19 disease directly with dysfunction of the complement pathways. This information lends support for a therapeutic anti-inflammatory strategy against complement, where a number of clinically ready potential therapeutic agents are available.

Title: COVID-19 & Periodontitis: The cytokine connection Content: COVID-19 is now recognized as a pandemic throughout the world, leading to a scramble in order to gather knowledge as well as evidence regarding the 'novel' corona virus which causes this disease. Chemokines are a family of cytokines which are chemotactic in nature and cause the recruitment of cells of inflammation. Periodontitis has long been attributed to having its pathophysiology rooted in a cytokine response. The recent COVID-19 pandemic has been reported to have adverse outcomes related to the establishment of a cytokine storm, many of the components of which are common with the cytokine expression profile of periodontitis. This communication explores the connection between COVID-19 and periodontal disease through their cytokine connection to form a translational basis for recommending maintenance of oral hygiene in the COVID era and to red flag patients with periodontitis as having an increased risk of exhibiting COVID related adverse outcomes.

Title: COVID-19 & Periodontitis: The cytokine connection. Content: COVID-19 is now recognized as a pandemic throughout the world, leading to a scramble in order to gather knowledge as well as evidence regarding the 'novel' corona virus which causes this disease. Chemokines are a family of cytokines which are chemotactic in nature and cause the recruitment of cells of inflammation. Periodontitis has long been attributed to having its pathophysiology rooted in a cytokine response. The recent COVID-19 pandemic has been reported to have adverse outcomes related to the establishment of a cytokine storm, many of the components of which are common with the cytokine expression profile of periodontitis. This communication explores the connection between COVID-19 and periodontal disease through their cytokine connection to form a translational basis for recommending maintenance of oral hygiene in the COVID era and to red flag patients with periodontitis as having an increased risk of exhibiting COVID related adverse outcomes.

Title: Should we stimulate or suppress immune responses in COVID-19? Cytokine and anti-cytokine interventions Content: Abstract The coronavirus disease-19 pandemic (COVID-19), which appeared in China in December 2019 and rapidly spread throughout the world, has forced clinicians and scientists to take up extraordinary challenges. This unprecedented situation led to the inception of numerous fundamental research protocols and many clinical trials. It quickly became apparent that although COVID-19, in the vast majority of cases, was a benign disease, it could also develop a severe form with sometimes fatal outcomes. Cytokines are central to the pathophysiology of COVID-19; while some of them are beneficial (type-I interferon, interleukin-7), others appear detrimental (interleukin-1β, -6, and TNF-α) particularly in the context of the so-called cytokine storm. Yet another characteristic of the disease has emerged: concomitant immunodeficiency, notably involving impaired type-I interferon response, and lymphopenia. This review provides an overview of current knowledge on COVID-19 immunopathology. We discuss the defective type-I IFN response, the theoretical role of IL-7 to restore lymphocyte repertoire, as well as we mention the two patterns observed in severe COVID-19 (i.e. interleukin-1β-driven macrophage activation syndrome vs. interleukin-6-driven immune dysregulation). Next, reviewing current evidence drawn from clinical trials, we examine a number of cytokine and anti-cytokine therapies, including interleukin-1, -6, and TNF inhibitors, as well as less targeted therapies, such as corticosteroids, chloroquine, or JAK inhibitors.

Title: COVID-19 and the Heart. Content: Infection with the novel coronavirus, SARS-CoV-2, produces a clinical syndrome known as COVID-19. When severe, COVID-19 is a systemic illness characterized by hyperinflammation, cytokine storm and elevations of cardiac injury biomarkers. Here we review what is known about the pathophysiology of COVID-19, its cardiovascular manifestations, and emerging therapeutic prospects. In this rapidly moving field, this review was comprehensive as of April 3, 2020.

Title: Novel therapeutic targets for SARS-CoV-2-induced acute lung injury: Targeting a potential IL-1β/neutrophil extracellular traps feedback loop. Content: Most COVID-19 infected individuals present with mild flu-like symptoms; however, 5-10% of cases suffer from life-threatening pneumonia and respiratory failure. The pathogenesis of SARS-CoV-2 and its pathology of associated acute lung injury (ALI), acute respiratory distress syndrome (ARDS), sepsis, coagulopathy and multiorgan failure is not known. SARS-CoV-2 is an envelope virus with S (spike), M (membrane), N (nucleocapsid) and E (envelop) proteins. In a closely related coronavirus (SARS-CoV), the transmembrane E protein exerts an important role in membrane-ionic transport through viroporins, deletion of which reduced levels of IL-1β and a remarkably reduced lung edema compared to wild type. IL-1β is generated by macrophages upon activation of intracellular NLRP3 (NOD-like, leucine rich repeat domains, and pyrin domain-containing protein 3), part of the functional NLRP3 inflammasome complex that detects pathogenic microorganisms and stressors, while neutrophils are enhanced by increasing levels of IL-1β. Expiring neutrophils undergo "NETosis", producing thread-like extracellular structures termed neutrophil extracellular traps (NETs), which protect against mild infections and microbes. However, uncontrolled NET production can cause acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), coagulopathy, multiple organ failure, and autoimmune disease. Herein, we present arguments underlying our hypothesis that IL-1β and NETs, mediated via NLRP3 inflammasomes, form a feed-forward loop leading to the excessive alveolar and endothelial damage observed in severe cases of COVID-19. Considering such assertions, we propose potential drug candidates that could be used to alleviate such pathologies. Considering that recent efforts to ascertain effective treatments of COVID-19 in severe patients has been less than successful, investigating novel avenues of treating this virus are essential.

Title: Altered cytokine levels and immune responses in patients with SARS-CoV-2 infection and related conditions Content: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic in early 2020. The infection has been associated with a wide range of clinical symptoms. In the severely affected patients, it has caused dysregulation of immune responses including over-secretion of inflammatory cytokines and imbalances in the proportion of naïve helper T cells, memory helper T cells and regulatory T cells. Identification of the underlying mechanism of such aberrant function of immune system would help in the prediction of disease course and selection of susceptible patients for more intensive cares. In the current review, we summarize the results of studies which reported alterations in cytokine levels and immune cell functions in patients affected with SARS-CoV-2 and related viruses.

Title: Molecular Alterations Prompted by SARS-CoV-2 Infection: Induction of Hyaluronan, Glycosaminoglycan and Mucopolysaccharide Metabolism Content: BACKGROUND: The SARS-CoV-2 is the etiological agent causing COVID-19 which has infected more than 2 million people with more than 200000 deaths since its emergence in December 2019. In the majority of cases patients are either asymptomatic or show mild to moderate symptoms and signs of a common cold. A subset of patients, however, develop a severe atypical pneumonia, with the characteristic ground-glass appearance on chest x-ray and computerized tomography, which evolves into an acute respiratory distress syndrome, that requires mechanical ventilation and eventually results in multiple organ failure and death. The Molecular pathogenesis of COVID-19 is still unknown. AIM OF THE STUDY: In the present work we performed a stringent metanalysis from the publicly available RNAseq data from bronchoalveolar cells and peripheral blood mononuclear cells to elucidate molecular alterations and cellular deconvolution to identify immune cell profiles. RESULTS: Alterations in genes involved in hyaluronan, glycosaminoglycan and mucopolysaccharides metabolism were over-represented in bronchoalveolar cells infected by SARS-CoV-2, as well as potential lung infiltration with neutrophils, T CD4+ cell and macrophages. The blood mononuclear cells presented a proliferative state. Dramatic reduction of NK and T lymphocytes, whereas an exacerbated increase in monocytes. CONCLUSIONS: In summary our results revealed molecular pathogenesis of the SARS-CoV-2 infection to bronchoalveolar cells inducing the hyaluronan and glycosaminoglycan metabolism that could shape partially the components of the ground-glass opacities observed in CT. And the potential immune response profile in COVID-19.

Title: STAT2 signaling as double-edged sword restricting viral dissemination but driving severe pneumonia in SARS-CoV-2 infected hamsters Content: Since the emergence of SARS-CoV-2 causing COVID-19, the world is being shaken to its core with numerous hospitalizations and hundreds of thousands of deaths. In search for key targets of effective therapeutics, robust animal models mimicking COVID-19 in humans are urgently needed. Here, we show that productive SARS-CoV-2 infection in the lungs of mice is limited and restricted by early type I interferon responses. In contrast, we show that Syrian hamsters are highly permissive to SARS- CoV-2 and develop bronchopneumonia and a strong inflammatory response in the lungs with neutrophil infiltration and edema. Moreover, we identify an exuberant innate immune response as a key player in pathogenesis, in which STAT2 signaling plays a dual role, driving severe lung injury on the one hand, yet restricting systemic virus dissemination on the other. Finally, we assess SARS-CoV- 2-induced lung pathology in hamsters by micro-CT alike used in clinical practice. Our results reveal the importance of STAT2-dependent interferon responses in the pathogenesis and virus control during SARS-CoV-2 infection and may help rationalizing new strategies for the treatment of COVID-19 patients.

Title: The case of complement activation in COVID-19 multiorgan impact Content: The novel coronavirus disease COVID-19 originates in the lungs, but it may extend to other organs, causing, in severe cases, multiorgan damage, including cardiac injury and acute kidney injury. In severe cases, the presence of kidney injury is associated with increased risk of death, highlighting the relevance of this organ as a target of SARS-CoV-2 infection. COVID-19-associated tissue injury is not primarily mediated by viral infection, but rather is a result of the inflammatory host immune response, which drives hypercytokinemia and aggressive inflammation that affect lung parenchymal cells, diminishing oxygen uptake, but also endothelial cells, resulting in endotheliitis and thrombotic events and intravascular coagulation. The complement system represents the first response of the host immune system to SARS-CoV-2 infection, but there is growing evidence that unrestrained activation of complement induced by the virus in the lungs and other organs plays a major role in acute and chronic inflammation, endothelial cell dysfunction, thrombus formation, and intravascular coagulation, and ultimately contributes to multiple organ failure and death. In this review, we discuss the relative role of the different complement activation products in the pathogenesis of COVID-19-associated tissue inflammation and thrombosis and propose the hypothesis that blockade of the terminal complement pathway may represent a potential therapeutic option for the prevention and treatment of lung and multiorgan damage.

Title: COVID-19: unravelling the clinical progression of nature's virtually perfect biological weapon Content: Coronavirus disease 2019 (COVID-19) pandemic has shocked the world and caused morbidity and mortality on an unprecedented level in the era of modern medicine Evidence generated to-date on the virulence and pathogenicity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) suggests that COVID-19 may be considered a perfect storm, caused by a nature's virtually perfect biological weapon This conclusion is supported by an updated analysis of pathogenesis and clinical progression of this infectious disease It is now readily apparent that COVID-19 is not a clear-cut disorder, but is instead a gradually evolving pathology, characterized by a series of stages sustained by different molecular and biological mechanisms The disease can hence be divided in at least five different phases (incubation, respiratory, pro-inflammatory, pro-thrombotic, and death or remission) Whilst the virus triggers direct cytopathic injury during the initial stage of illness, in the following evolving phases, it is the host itself that undergoes an almost suicidal reaction, sustained, amplified and maintained by the immune, complement and hemostatic systems Another peculiar property making SARS-CoV-2 a devious and vicious pathogen is the biophysical structure of its receptor biding domain, which needs to be primed by human proteases, thus being less efficiently targetable by the host immune system The unique pathophysiology of COVID-19 requires the customization of therapy by individual patient characteristics and according to the phase-specific, evolving derangement of the multiple biological pathways

Title: COVID-19: a collision of complement, coagulation and inflammatory pathways Content: COVID-19 is frequently accompanied by a hypercoagulable inflammatory state with microangiopathic pulmonary changes that can precede the diffuse alveolar damage characteristic of typical ARDS seen in other severe pathogenic infections. Parallels with systemic inflammatory disorders such as atypical haemolytic uraemic syndrome (aHUS) have implicated the complement pathway in the pathogenesis of COVID-19, and particularly the anaphylatoxins C3a and C5a released from cleavage of C3 and C5 respectively. C5a is a potent cell signalling protein that activates a cytokine storm - a hyper-inflammatory phenomenon - within hours of infection and the innate immune response. However, excess C5a can result in a pro-inflammatory environment orchestrated through a plethora of mechanisms, that propagates lung injury, lymphocyte exhaustion and an immune paresis. Furthermore, disruption of the homeostatic interactions between complement and extrinsic and intrinsic coagulation pathways contributes to a net pro-coagulant state in the microvasculature of critical organs. Fatal COVID-19 has been associated with a systemic inflammatory response accompanied by a pro-coagulant state and organ damage, particularly microvascular thrombi in the lungs and kidneys. Pathologic studies report strong evidence of complement activation. C5 blockade reduces inflammatory cytokines and their manifestations in animal studies, and has shown benefits in patients with aHUS, prompting investigation of this approach in the treatment of COVID-19. This review describes the role of the complement pathway and particularly C5a and its aberrations in highly pathogenic virus infections, and therefore its potential as a therapeutic target in COVID-19.

Title: Distinct infection process of SARS‐CoV‐2 in human bronchial epithelial cells line Content: COVID‐19, caused by SARS‐CoV‐2, leads to a series of clinical symptoms of respiratory and pulmonary inflammatory reactions via unknown pathologic mechanisms related to the viral infection process in tracheal or bronchial epithelial cells. Investigation of this viral infection in the human bronchial epithelial cell line (16HBE) suggests that SARS‐CoV‐2 can enter these cells through interaction between its membrane‐localized S protein with the ACE2 molecule on the host cell membrane. Further observation indicates distinct viral replication with a dynamic and moderate increase, whereby viral replication does not lead to a specific cytopathic effect but maintains a continuous release of progeny virions from infected cells. Although mRNA expression of various innate immune signaling molecules is altered in the cells, transcription of IFNα, IFNβ and IFNγ is unchanged. Furthermore, expression of some interleukins related to inflammatory reactions, such as IL‐6, IL‐2 and IL‐8, is maintained at low levels, whereas that of interleukins involved in immune regulation is upregulated. Interestingly, IL‐22, an interleukin that functions mainly in tissue repair, shows very high expression. Collectively, these data suggest a distinct infection process for this virus in respiratory epithelial cells, which may be linked to its clinicopathological mechanism. This article is protected by copyright. All rights reserved.

Title: Potential Causes and Consequences of Gastrointestinal Disorders during a SARS-CoV-2 Infection Content: Coronaviruses cause several human diseases, including severe acute respiratory syndrome. The global coronavirus disease 2019 (COVID-19) pandemic has become a huge threat to humans. Intensive research on the pathogenic mechanisms used by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is urgently needed-notably to identify potential drug targets. Clinical studies of patients with COVID-19 have shown that gastrointestinal disorders appear to precede or follow the respiratory symptoms. Here, we review gastrointestinal disorders in patients with COVID-19, suggest hypothetical mechanisms leading to gut symptoms, and discuss the potential consequences of gastrointestinal disorders on the outcome of the disease. Lastly, we discuss the role of the gut microbiota during respiratory viral infections and suggest that targeting gut dysbiosis may help to control the pathogenesis of COVID-19.

Title: Rationale for targeting Complement in COVID-19 Content: A novel coronavirus, SARS-CoV-2, has recently emerged in China and spread internationally, posing a health emergency to the global community. COVID-19 caused by SARS-CoV-2 is associated with an acute respiratory illness that varies from mild to the life-threatening acute respiratory distress syndrome (ARDS). The complement system is part of the innate immune arsenal against pathogens, which many viruses can evade or employ to mediate cell entry. The immunopathology and acute lung injury orchestrated through the influx of pro-inflammatory macrophages and neutrophils can be directly activated by complement components to prime an overzealous cytokine storm. The manifestations of severe COVID-19 such as the ARDS, sepsis and multiorgan failure have an established relationship with activation of the complement cascade. We have collected evidence from all the current studies we are aware of on SARS-CoV-2 immunopathogenesis and the preceding literature on SARS-CoV-1 and MERS-CoV infection linking severe COVID-19 disease directly with dysfunction of the complement pathways. This information lends support for a therapeutic anti-inflammatory strategy against complement, where a number of clinically ready potential therapeutic agents are available.

Title: Type 3 hypersensitivity in COVID-19 vasculitis Content: Coronavirus Disease 2019 (COVID-19) is an ongoing public health emergency and new knowledge about its immunopathogenic mechanisms is deemed necessary in the attempt to reduce the death burden around the world. For the first time in worldwide literature, we provide scientific evidence that in COVID-19 vasculitis a life-threatening escalation from type 2 T-helper immune response (humoral immunity) to type 3 hypersensitivity (immune complex disease) takes place. The subsequent deposition of immune complexes inside the vascular walls is supposed to induce a severe inflammatory state and a cytokine release syndrome, whose interleukin-6 is the key myokine, from the smooth muscle cells of blood vessels.

Title: Mechanisms of Myocardial Injury in Coronavirus Disease 2019 Content: Coronavirus disease 2019 (COVID-19) predominantly presents with symptoms of fever, fatigue, cough and respiratory failure. However, it appears to have a unique interplay with cardiovascular disease (CVD); patients with pre-existing CVD are at highest risk for mortality from COVID-19, along with the elderly. COVID-19 contributes to cardiovascular complications including arrhythmias, myocardial dysfunction and myocardial inflammation. Although the exact mechanism of myocardial inflammation in patients with COVID-19 is not known, several plausible mechanisms have been proposed based on early observational reports. In this article, the authors summarise the available literature on mechanisms of myocardial injury in COVID-19.

Title: COVID-19 for the Cardiologist: A Current Review of the Virology, Clinical Epidemiology, Cardiac and Other Clinical Manifestations and Potential Therapeutic Strategies Content: Summary The coronavirus disease-2019 (COVID-19), a contagious disease caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV2), has reached pandemic status. As it spreads across the world, it has overwhelmed healthcare systems, strangled the global economy and led to a devastating loss of life. Widespread efforts from regulators, clinicians and scientists are driving a rapid expansion of knowledge of the SARS-CoV2 virus and the COVID-19 disease. We review the most current data with a focus on our basic understanding of the mechanism(s) of disease and translation to the clinical syndrome and potential therapeutics. We discuss the basic virology, epidemiology, clinical manifestation, multi-organ consequences, and outcomes. With a focus on cardiovascular complications, we propose several mechanisms of injury. The virology and potential mechanism of injury form the basis for a discussion of potential disease-modifying therapies.

Title: COVID-19 Sepsis and Microcirculation Dysfunction Content: The spreading of Coronavirus (SARS-CoV-2) pandemic, known as COVID-19, has caused a great number of fatalities all around the World. Up to date (2020 May 6) in Italy we had more than 28,000 deaths, while there were more than 205.000 infected. The majority of patients affected by COVID-19 complained only slight symptoms: fatigue, myalgia or cough, but more than 15% of Chinese patients progressed into severe complications, with acute respiratory distress syndrome (ARDS), needing intensive treatment. We tried to summarize data reported in the last months from several Countries, highlighting that COVID-19 was characterized by cytokine storm (CS) and endothelial dysfunction in severely ill patients, where the progression of the disease was fast and fatal. Endothelial dysfunction was the fundamental mechanism triggering a pro-coagulant state, finally evolving into intravascular disseminated coagulation, causing embolization of several organs and consequent multiorgan failure (MOF). The Italian Society of Clinical Hemorheology and Microcirculation was aimed to highlight the role of microcirculatory dysfunction in the pathogenetic mechanisms of COVID-19 during the spreading of the biggest challenges to the World Health.

Title: Cytokine Storm Induced by SARS-CoV-2 Content: A novel coronavirus disease 2019 (COVID-19) triggered by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently spreading globally, causing severe pneumonia and acute lung injury in many patients. Even worse, severe respiratory may develop into acute respiratory distress syndrome and multiple organ dysfunction syndrome in COVID-19. The cytokine storm caused by immune over-activation due to virus infection may be an important cause of death in the late period of progress, but the pathogenesis of cytokine storm is still unclear. This article reviews the mechanisms of SARS-CoV-2-induced cytokine storm in detail based on the current discovered researches, and put forward some valuable medication ideas for the targeted cytokines drug researches and treatment. The goal of this work will be helpful for reducing excessive immune response.

Title: Coronavirus Disease 2019-related dyspnea cases difficult to interpret using chest computed tomography Content: Abstract Patients with Coronavirus Disease 2019 (COVID-19) often have clinical characteristics, such as chest tightness and dyspnea. Continuous, unresolved dyspnea often indicates the progression of lung lesions. The mechanism that underlies the chest distress and dyspnea in patients with COVID-19 is still unclear. Chest CT has a higher sensitivity and can play an essential role in the diagnosis and treatment of the disease. However, our clinical observations showed that although some patients had significant chest distress and dyspnea, the lesions that were observed in the lungs during computed tomography were milder and not completely consistent with clinical symptoms. We analyzed the clinical characteristics, laboratory test results, and imaging findings of these patients. We found that extensive inflammation of the bilateral and respiratory bronchioles in patients with COVID-19 due to excessive activation of proinflammatory cytokines and chemotactic aggregation of T-lymphocytes at the site of inflammation are possible mechanisms underlying chest distress and dyspnea in patients with COVID-19. Short-time and lose-dose use of corticosteroid may be helpful to treat chest tightness and dyspnea in mild COVID-19 patients. Through this study, we aimed to improve our understanding of the pathogenesis of COVID-19.