Question: What is the mechanism of cytokine storm syndrome on the COVID-19?

Title: Tocilizumab Administration in Patients with SARS‐CoV‐2 Infection: Subcutaneous Injection versus Intravenous Infusion Content: Recent studies have revealed that cytokine storm syndrome, which is caused by the activation of inflammatory cytokines, is a likely underlying pathophysiology in patients with severe COVID‐19 that has been associated with a high mortality rate(1). This article is protected by copyright. All rights reserved.

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: 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: [Advances in the research of mechanism and related immunotherapy on the cytokine storm induced by coronavirus disease 2019] Content: Coronavirus disease 2019 (COVID-19) has seriously affected the safety of patients and social stability. Some COVID-19 patients in the later stage of disease may develop into acute respiratory distress syndrome or even multiple organ failure. However, one of the most important mechanisms underlying the deterioration of disease is cytokine storm. At present, some therapies such as interleukin-6 antibody blocker, stem cell therapy, and transfusion of convalescent plasma have been applied to counteract the cytokine storm with some progresses being achieved. This article reviews the influences of cytokine storm syndrome on the COVID-19 and the corresponding immunotherapies to resist cytokine storm.

Title: Cytokine storm induced by SARS-CoV-2 Content: Coronavirus disease 2019 (COVID-19), caused by the virus designated as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has spread widely throughout the world. Despite the strict global outbreak management and quarantine measures that have been implemented, the incidence of COVID-19 continues to rise, resulting in more than 290,000 deaths and representing an extremely serious threat to human life and health. The clinical symptoms of the affected patients are heterogeneous, ranging from mild upper respiratory symptoms to severe pneumonitis and even acute respiratory distress syndrome (ARDS) or death. Systemic immune over activation due to SARS-CoV-2 infection causes the cytokine storm, which is especially noteworthy in severely ill patients with COVID-19. Pieces of evidence from current studies have shown that the cytokine storm may be an important factor in disease progression, even leading to multiple organ failure and death. This review provides an overview of the knowledge on the COVID-19 epidemiological profile, the molecular mechanisms of the SARS-CoV-2-induced cytokine storm and immune responses, the pathophysiological changes that occur during infection, the main antiviral compounds used in treatment strategies and the potential drugs for targeting cytokines, this information is presented to provide valuable guidance for further studies and for a therapeutic reduction of this excessive immune response.

Title: [Advances in the research of cytokine storm mechanism induced by Corona Virus Disease 2019 and the corresponding immunotherapies] Content: Corona Virus Disease 2019 (COVID-19) has seriously affected the treatment of patients and social stability. In the later stage of disease, some COVID-19 patients may develop into acute respiratory distress syndrome or even multiple organ failure. However, one of the most important mechanism underlying the deterioration of disease is cytokine storm. At present, some therapies such as interleukin-6 antibody blocker, stem cell therapy, and transfusion of convalescent plasma have been applied to counteract the cytokine storm and have made some progress. This article reviews the influences of cytokine storm syndrome on the COVID-19 and the corresponding immunotherapies to resist cytokine storm.

Title: [Advances in the research of cytokine storm mechanism induced by Corona Virus Disease 2019 and the corresponding immunotherapies]. Content: Corona Virus Disease 2019 (COVID-19) has seriously affected the treatment of patients and social stability. In the later stage of disease, some COVID-19 patients may develop into acute respiratory distress syndrome or even multiple organ failure. However, one of the most important mechanism underlying the deterioration of disease is cytokine storm. At present, some therapies such as interleukin-6 antibody blocker, stem cell therapy, and transfusion of convalescent plasma have been applied to counteract the cytokine storm and have made some progress. This article reviews the influences of cytokine storm syndrome on the COVID-19 and the corresponding immunotherapies to resist cytokine storm.

Title: 2019 Novel Coronavirus Pandemic: What Do We Know? Content: The pandemic caused by SARS-COV2 Virus/COVID-19, which was initially reported in China in December 2019, has become a major global health concern. COVID-19 can manifest with cytokine storm - an exaggerated systemic inflammatory phenomenon due to over-production of proinflammatory cytokines by immune cells that results in diffuse inflammatory lung disease and acute respiratory distress syndrome. It may be complicated by septic shock and subsequent multi-organ failure. Based on the most recently published evidence, this article will review and discuss comprehensive information on its clinical manifestations, laboratory tests, potential therapeutics, and prevention guidelines.

Title: Weathering the COVID-19 storm: Lessons from hematologic cytokine syndromes Content: A subset of patients with severe COVID-19 develop profound inflammation and multi-organ dysfunction consistent with a "Cytokine Storm Syndrome" (CSS). In this review we compare the clinical features, diagnosis, and pathogenesis of COVID-CSS with other hematological CSS, namely secondary hemophagocytic lymphohistiocytosis (sHLH), idiopathic multicentric Castleman disease (iMCD), and CAR-T cell therapy associated Cytokine Release Syndrome (CRS). Novel therapeutics targeting cytokines or inhibiting cell signaling pathways have now become the mainstay of treatment in these CSS. We review the evidence for cytokine blockade and attenuation in these known CSS as well as the emerging literature and clinical trials pertaining to COVID-CSS. Established markers of inflammation as well as cytokine levels are compared and contrasted between these four entities in order to establish a foundation for future diagnostic criteria of COVID-CSS.

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: Weathering the COVID-19 storm: Lessons from hematologic cytokine syndromes Content: A subset of patients with severe COVID-19 develop profound inflammation and multi-organ dysfunction consistent with a “Cytokine Storm Syndrome” (CSS). In this review we compare the clinical features, diagnosis, and pathogenesis of COVID-CSS with other hematological CSS, namely secondary hemophagocytic lymphohistiocytosis (sHLH), idiopathic multicentric Castleman disease (iMCD), and CAR-T cell therapy associated Cytokine Release Syndrome (CRS). Novel therapeutics targeting cytokines or inhibiting cell signaling pathways have now become the mainstay of treatment in these CSS. We review the evidence for cytokine blockade and attenuation in these known CSS as well as the emerging literature and clinical trials pertaining to COVID-CSS. Established markers of inflammation as well as cytokine levels are compared and contrasted between these four entities in order to establish a foundation for future diagnostic criteria of COVID-CSS.

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: Extracorporeal blood purification treatment options for COVID-19: The role of immunoadsorption Content: The activation of the innate and adaptive immune systems by SARS-CoV-2 causes the release of several inflammatory cytokines, including IL-6. The inflammatory hypercytokinemia causes immunopathological changes in the lungs including vascular leakage, and alveolar edema. As a result of these changes in the lungs, hypoxia and acute respiratory distress syndrome occur in patients with COVID-19. Even though there are clinical trials on the development of therapeutics and vaccines, there are currently no licensed vaccines or therapeutics for COVID-19. Pharmacological approaches have shown poor results in sepsis-like syndromes caused by the hypercytokinemia. Suppressing the cytokine storm is an important way to prevent the organ damage in patients with COVID-19. Extracorporeal blood purification could be proposed as an adjunctive therapy for sepsis, aiming to control the associated dysregulation of the immune system, which is known to protect organ functions. Several extracorporeal blood purification therapies are now available, and most of them target endotoxins and/or the cytokines and aim improving the immune response. For this purpose, plasmapheresis and immunoadsorption may be an important adjunctive treatment option to manage the complications caused by cytokine storm in critically ill patients with COVID-19.

Title: Cytokine Storm in COVID19: A Neural Hypothesis Content: Cytokine storm in COVID-19 is characterized by an excessive inflammatory response to SARS-CoV-2 that is caused by a dysregulated immune system of the host. We are proposing a new hypothesis that SARS-CoV-2 mediated inflammation of nucleus tractus solitarius (NTS) may be responsible for the cytokine storm in COVID 19. The inflamed NTS may result in a dysregulated cholinergic anti-inflammatory pathway and hypothalamic-pituitary-adrenal axis.

Title: Cytokine Storm in COVID19: A Neural Hypothesis. Content: Cytokine storm in COVID-19 is characterized by an excessive inflammatory response to SARS-CoV-2 that is caused by a dysregulated immune system of the host. We are proposing a new hypothesis that SARS-CoV-2 mediated inflammation of nucleus tractus solitarius (NTS) may be responsible for the cytokine storm in COVID 19. The inflamed NTS may result in a dysregulated cholinergic anti-inflammatory pathway and hypothalamic-pituitary-adrenal axis.

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: On the Alert for Cytokine Storm: Immunopathology in COVID-19 Content: Poor outcomes in COVID-19 correlate with clinical and laboratory features of cytokine storm syndrome. Broad screening for cytokine storm and early, targeted antiinflammatory therapy may prevent immunopathology and could help conserve limited health care resources. While studies are ongoing, extrapolating from clinical experience in cytokine storm syndromes may benefit the multidisciplinary teams caring for patients with severe COVID-19.

Title: Lymphopenia in COVID-19: Therapeutic opportunities Content: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is uncontrollably spread all over the world. The host immune responses strongly try to confront it with all the potential cells and cytokines. With chronically condition of SARS-CoV-2, natural killer cells and T cells become exhausted and decreasing their count leads to lymphopenia. Inability to eradicate the infected organ makes hyperinitiation of the immune system, which releases the excessive inflammatory cytokines to compensate the exhausted one as well as the low lymphocytes counts; it consequently leads to the cytokine storm syndrome. These mechanisms and the potential therapeutic targeting are discussed in this paper.

Title: On the Alert for Cytokine Storm: Immunopathology in COVID‐19 Content: Poor outcomes in COVID‐19 correlate with clinical and laboratory features of cytokine storm syndrome. Broad screening for cytokine storm and early, targeted antiinflammatory therapy may prevent immunopathology and could help conserve limited health care resources. While studies are ongoing, extrapolating from clinical experience in cytokine storm syndromes may benefit the multidisciplinary teams caring for patients with severe COVID‐19.

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: 2019 Novel Coronavirus Pandemic: What Do We Know? Content: The pandemic caused by SARS-COV2 Virus/COVID-19, which was initially reported in China in December 2019, has become a major global health concern COVID-19 can manifest with cytokine storm - an exaggerated systemic inflammatory phenomenon due to over-production of proinflammatory cytokines by immune cells that results in diffuse inflammatory lung disease and acute respiratory distress syndrome It may be complicated by septic shock and subsequent multi-organ failure Based on the most recently published evidence, this article will review and discuss comprehensive information on its clinical manifestations, laboratory tests, potential therapeutics, and prevention guidelines

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 cytokine storm: The anger of inflammation Content: Patients with COVID-19 who require ICU admission might have the cytokine storm. It is a state of out-of-control release of a variety of inflammatory cytokines. The molecular mechanism of the cytokine storm has not been explored extensively yet. The attachment of SARS-CoV-2 spike glycoprotein with angiotensin-converting enzyme 2 (ACE2), as its cellular receptor, triggers complex molecular events that leads to hyperinflammation. Four molecular axes that may be involved in SARS-CoV-2 driven inflammatory cytokine overproduction are addressed in this work. The virus-mediated down-regulation of ACE2 causes a burst of inflammatory cytokine release through dysregulation of the renin-angiotensin-aldosterone system (ACE/angiotensin II/AT1R axis), attenuation of Mas receptor (ACE2/MasR axis), increased activation of [des-Arg9]-bradykinin (ACE2/bradykinin B1R/DABK axis), and activation of the complement system including C5a and C5b-9 components. The molecular clarification of these axes will elucidate an array of therapeutic strategies to confront the cytokine storm in order to prevent and treat COVID-19 associated acute respiratory distress syndrome.

Title: Extracorporeal Blood Purification Treatment Options for COVID-19: The Role of Immunoadsorption Content: Abstract The activation of theinnate and adaptive immune systems by SARS-CoV-2 causes the release of several inflammatory cytokines, including IL-6. The inflammatory hypercytokinemia causes immunopathological changes in the lungs including vascular leakage, and alveolar edema. As a result of these changes in the lungs, hypoxia and acute respiratory distress syndrome occur in patients with COVID-19. Even though there are clinical trials on the development of therapeutics and vaccines, there are currently no licensed vaccines or therapeutics for COVID-19. Pharmacological approaches have shown poor results in sepsis-like syndromes caused by the hypercytokinemia. Suppressing the cytokine storm is an important way to prevent the organ damage in patients with COVID-19. Extracorporeal blood purification could be proposed as an adjunctive therapy for sepsis, aiming to control the associated dysregulation of the immune system, which is known to protect organ functions. Several extracorporeal blood purification therapies are now available, and most of them target endotoxins and/or the cytokines and aim improving the immune response. For this purpose, plasmapheresis and immunoadsorption may be an important adjunctive treatment option to manage the complications caused by cytokine storm in critically ill patients with COVID-19.

Title: Lung under attack by COVID-19-induced cytokine storm: pathogenic mechanisms and therapeutic implications Content: The lung is a key target of the cytokine storm that can be triggered by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), responsible for the widespread clinical syndrome known as coronavirus disease 2019 (COVID-19). Indeed, in some patients, SARS-CoV-2 promotes a dysfunctional immune response that dysregulates the cytokine secretory pattern. Hypercytokinemia underlies the hyperinflammatory state leading to injury of alveolar epithelial cells and vascular endothelial cells, as well as to lung infiltration sustained by neutrophils and macrophages. Within such a pathogenic context, interleukin-6 (IL-6) and other cytokines/chemokines play a pivotal pro-inflammatory role. Therefore, cytokines and their receptors, as well as cytokine-dependent intracellular signalling pathways can be targeted by potential therapies aimed to relieve the heavy burden of cytokine storm. In particular, the anti-IL-6-receptor monoclonal antibody tocilizumab is emerging as one of the most promising pharmacologic treatments. The reviews of this paper are available via the supplemental material section.

Title: Targeting JAK-STAT Signaling to Control Cytokine Release Syndrome in COVID-19 Content: Recent advances in the pathophysiologic understanding of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has indicated that patients with severe coronavirus disease 2019 (COVID-19) might experience cytokine release syndrome (CRS), characterized by increased interleukin (IL)-6, IL-2, IL-7, IL-10, etc. Therefore, the treatment of cytokine storm has been proposed as a critical part of rescuing severe COVID-19. Several of the cytokines involved in COVID-19 employ a distinct intracellular signaling pathway mediated by Janus kinases (JAKs). JAK inhibition, therefore, presents an attractive therapeutic strategy for CRS, which is a common cause of adverse clinical outcomes in COVID-19. Below, we review the possibilities and challenges of targeting the pathway in COVID-19.

Title: Lymphopenia in COVID‐19: Therapeutic opportunities Content: Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is uncontrollably spread all over the world. The host immune responses strongly try to confront it with all the potential cells and cytokines. With chronically condition of SARS‐CoV‐2, natural killer cells and T cells become exhausted and decreasing their count leads to lymphopenia. Inability to eradicate the infected organ makes hyperinitiation of the immune system, which releases the excessive inflammatory cytokines to compensate the exhausted one as well as the low lymphocytes counts; it consequently leads to the cytokine storm syndrome. These mechanisms and the potential therapeutic targeting are discussed in this paper.

Title: The amount of cytokine-release defines different shades of Sars-Cov2 infection Content: The recent outbreak of coronavirus disease (COVID 19), spreading from China all around the world in early 2020, has led scientists to investigate the immuno-mediated mechanisms underlying the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) infection. Depending on the amount of cytokines released as the result of the immunological activation induced by SARS-CoV2, three major clinical phenotypes can be identified: "mild",symbolized as a "drizzle" of cytokines, severe as a "storm", and critical as a "hurricane". In patients with mild symptoms, the release of pro-inflammatory cytokines is balanced to obtain a defense response against the virus which is often self-limiting and overcomes without tissue damage. In severe phenotype, resembling a "cytokine-release syndrome", SARS-CoV2 causes the lysis of the immune-mediators leading to a cytokine storm able to induce lung epithelium damage and acute respiratory distress syndrome. In critical patients, the immune response may become uncontrolled, thus the cytokine burst resembles a form of secondary hemophagocytic lymphohistiocytosis which may result in a multi organ failure. In addition to the standard of care, an immune-modulatory therapy tailored to each one of the different phenotypes should be used in order to prevent or reduce the release of cytokines responsible for organ damage and disease progression.

Title: The amount of cytokine-release defines different shades of Sars-Cov2 infection. Content: The recent outbreak of coronavirus disease (COVID 19), spreading from China all around the world in early 2020, has led scientists to investigate the immuno-mediated mechanisms underlying the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) infection. Depending on the amount of cytokines released as the result of the immunological activation induced by SARS-CoV2, three major clinical phenotypes can be identified: "mild",symbolized as a "drizzle" of cytokines, severe as a "storm", and critical as a "hurricane". In patients with mild symptoms, the release of pro-inflammatory cytokines is balanced to obtain a defense response against the virus which is often self-limiting and overcomes without tissue damage. In severe phenotype, resembling a "cytokine-release syndrome", SARS-CoV2 causes the lysis of the immune-mediators leading to a cytokine storm able to induce lung epithelium damage and acute respiratory distress syndrome. In critical patients, the immune response may become uncontrolled, thus the cytokine burst resembles a form of secondary hemophagocytic lymphohistiocytosis which may result in a multi organ failure. In addition to the standard of care, an immune-modulatory therapy tailored to each one of the different phenotypes should be used in order to prevent or reduce the release of cytokines responsible for organ damage and disease progression.

Title: Cytokine storm and leukocyte changes in mild versus severe SARS-CoV-2 infection: Review of 3939 COVID-19 patients in China and emerging pathogenesis and therapy concepts Content: Clinical evidence indicates that the fatal outcome observed with severe acute respiratory syndrome-coronavirus-2 infection often results from alveolar injury that impedes airway capacity and multi-organ failure-both of which are associated with the hyperproduction of cytokines, also known as a cytokine storm or cytokine release syndrome. Clinical reports show that both mild and severe forms of disease result in changes in circulating leukocyte subsets and cytokine secretion, particularly IL-6, IL-1ß, IL-10, TNF, GM-CSF, IP-10 (IFN-induced protein 10), IL-17, MCP-3, and IL-1ra. Not surprising, therapies that target the immune response and curtail the cytokine storm in coronavirus 2019 (COVID-19) patients have become a focus of recent clinical trials. Here we review reports on leukocyte and cytokine data associated with COVID-19 disease in 3939 patients in China and describe emerging data on immunopathology. With an emphasis on immune modulation, we also look at ongoing clinical studies aimed at blocking proinflammatory cytokines; transfer of immunosuppressive mesenchymal stem cells; use of convalescent plasma transfusion; as well as immunoregulatory therapy and traditional Chinese medicine regimes. In examining leukocyte and cytokine activity in COVID-19, we focus in particular on how these levels are altered as the disease progresses (neutrophil NETosis, macrophage, T cell response, etc.) and proposed consequences to organ pathology (coagulopathy, etc.). Viral and host interactions are described to gain further insight into leukocyte biology and how dysregulated cytokine responses lead to disease and/or organ damage. By better understanding the mechanisms that drive the intensity of a cytokine storm, we can tailor treatment strategies at specific disease stages and improve our response to this worldwide public health threat.

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: Targeting JAK-STAT Signaling to Control Cytokine Release Syndrome in COVID-19 Content: Recent advances in the pathophysiologic understanding of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has indicated that patients with severe COVID-19 might experience cytokine release syndrome (CRS), characterized by increased interleukin (IL)-6, IL-2, IL-7, IL-10, etc. Therefore, the treatment of cytokine storm has been proposed as a critical part of rescuing severe COVID-19. Several of the cytokines involved in COVID-19 employ a distinct intracellular signaling pathway mediated by Janus kinases (JAKs). JAK inhibition, therefore, presents an attractive therapeutic strategy for CRS, which is a common cause of adverse clinical outcomes in COVID-19. Below, we review the possibilities and challenges of targeting the pathway in COVID-19.

Title: Bilateral anterior uveitis as a part of a multisystem inflammatory syndrome secondary to COVID-19 infection Content: During the ongoing COVID-19 pandemic, there is a global concern about patients presenting with inflammatory syndrome with variable clinical features. Colanfrancesco et al. described COVID-19 systemic inflammatory reaction that are characterized by a life-threatening hyper-inflammation sustained by a cytokines storm which eventually leads to multi-organ failure. This article is protected by copyright. All rights reserved.

Title: COVID-19 gone bad: A new character in the spectrum of the hyperferritinemic syndrome? Content: The severe form of COVID-19 share several clinical and laboratory features with four entities gathered under the term "hyperferritinemic syndromes" and including macrophage activation syndrome (MAS), adult-onset Still's disease (AOSD), catastrophic anti-phospholipid syndrome (CAPS) and septic shock. COVID-19 systemic inflammatory reaction and "hyperferritinemic syndromes" are all characterized by high serum ferritin and a life-threatening hyper-inflammation sustained by a cytokines storm which eventually leads to multi-organ failure. In this review, we analyze the possible epidemiological and molecular mechanisms responsible for hyper-inflammation in patients with severe COVID-19 and we underline the similarities between this condition and "hyperferritinemic syndromes" which would allow considering severe COVID-19 as a fifth member of this spectrum of inflammatory conditions.

Title: Absence of severe complications from SARS-CoV-2 infection in children with rheumatic diseases treated with biologic drugs Content: We read with interest the Editorial by Cron and Chatam (1) suggesting a cytokine storm syndrome (CSS) occurring in response to SARS-CoV-2 infection and, consequently, a possible role for targeted approaches to blocking inflammatory cytokines.

Title: Absence of severe complications from SARS-CoV-2 infection in children with rheumatic diseases treated with biologic drugs. Content: We read with interest the Editorial by Cron and Chatam (1) suggesting a cytokine storm syndrome (CSS) occurring in response to SARS-CoV-2 infection and, consequently, a possible role for targeted approaches to blocking inflammatory cytokines.

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: COVID-19 gone bad: A new character in the spectrum of the hyperferritinemic syndrome? Content: Abstract The severe form of COVID-19 share several clinical and laboratory features with four entities gathered under the term “hyperferritinemic syndrome” and including macrophage activation syndrome (MAS), adult-onset Still's disease (AOSD), catastrophic anti-phospholipid syndrome (CAPS) and septic shock. COVID-19 systemic inflammatory reaction and “hyperferritinemic syndromes” are all characterized by high serum ferritin and a life-threatening hyper-inflammation sustained by a cytokines storm which eventually leads to multi-organ failure. In this review, we analyze the possible epidemiological and molecular mechanisms responsible for hyper-inflammation in patients with severe COVID-19 and we underline the similarities between this condition and “hyperferritinemic syndromes” which would allow considering this entity as the fifth member of the spectrum of inflammatory conditions.

Title: Cytokine storm and leukocyte changes in mild versus severe SARS‐CoV‐2 infection: Review of 3939 COVID‐19 patients in China and emerging pathogenesis and therapy concepts Content: Clinical evidence indicates that the fatal outcome observed with severe acute respiratory syndrome‐coronavirus‐2 infection often results from alveolar injury that impedes airway capacity and multi‐organ failure—both of which are associated with the hyperproduction of cytokines, also known as a cytokine storm or cytokine release syndrome. Clinical reports show that both mild and severe forms of disease result in changes in circulating leukocyte subsets and cytokine secretion, particularly IL‐6, IL‐1β, IL‐10, TNF, GM‐CSF, IP‐10 (IFN‐induced protein 10), IL‐17, MCP‐3, and IL‐1ra. Not surprising, therapies that target the immune response and curtail the cytokine storm in coronavirus 2019 (COVID‐19) patients have become a focus of recent clinical trials. Here we review reports on leukocyte and cytokine data associated with COVID‐19 disease in 3939 patients in China and describe emerging data on immunopathology. With an emphasis on immune modulation, we also look at ongoing clinical studies aimed at blocking proinflammatory cytokines; transfer of immunosuppressive mesenchymal stem cells; use of convalescent plasma transfusion; as well as immunoregulatory therapy and traditional Chinese medicine regimes. In examining leukocyte and cytokine activity in COVID‐19, we focus in particular on how these levels are altered as the disease progresses (neutrophil NETosis, macrophage, T cell response, etc.) and proposed consequences to organ pathology (coagulopathy, etc.). Viral and host interactions are described to gain further insight into leukocyte biology and how dysregulated cytokine responses lead to disease and/or organ damage. By better understanding the mechanisms that drive the intensity of a cytokine storm, we can tailor treatment strategies at specific disease stages and improve our response to this worldwide public health threat.

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: Storm, typhoon, cyclone or hurricane in patients with COVID-19? Beware of the same storm that has a different origin Content: Some of the articles being published during the severe acute respiratory syndrome-coronavirus (SARS-CoV)-2 pandemic highlight a link between severe forms of coronavirus disease 2019 (COVID-19) and the so-called cytokine storm, also with increased ferritin levels. However, this scenario is more complex than initially thought due to the heterogeneity of hyperinflammation. Some patients with coronavirus 2019 disease (COVID-19) develop a fully blown secondary haemophagocytic lymphohistiocytosis (sHLH), whereas others, despite a consistent release of pro-inflammatory cytokines, do not fulfil sHLH criteria but still show some features resembling the phenotype of the hyperferritinemic syndrome. Despite the final event (the cytokine storm) is shared by various conditions leading to sHLH, the aetiology, either infectious, autoimmune or neoplastic, accounts for the differences in the various phases of this process. Moreover, the evidence of a hyperinflammatory microenvironment provided the rationale to employ immunomodulating agents for therapeutic purposes in severe COVID-19. This viewpoint aims at discussing the pitfalls and issues to be considered with regard to the use of immunomodulating agents in COVID-19, such as timing of treatment based on the viral load and the extent of cytokine/ferritin overexpression. Furthermore, it encompasses recent findings in the paediatric field about a novel multisystem inflammatory disease resembling toxic shock syndrome and atypical Kawasaki disease observed in children with proven SARS-CoV2 infection. Finally, it includes arguments in favour of adding COVID-19 to the spectrum of the recently defined 'hyperferritinemic syndrome', which already includes adult-onset Still's disease, macrophage activation syndrome, septic shock and catastrophic anti-phospholipid syndrome.

Title: Role of Interleukin-6 in Lung Complications in Patients With COVID-19: Therapeutic Implications. Content: COVID-19 is viral respiratory infection with frequently fatal lung complications in the elderly or in people with serious comorbidities. Lung destruction appears to be associated with a cytokine storm related to an increased level of interleukin-6 (IL6). Therapeutic targeting of the interleukin-6 signaling pathway can attenuate such a cytokine storm and can be beneficial for patients with COVID-19 in danger of pulmonary failure. This article demonstrates the importance of IL6 in progression of disease and the possibility of inhibition of IL6 signaling in COVID-19 therapy.

Title: Role of Interleukin-6 in Lung Complications in Patients With COVID-19: Therapeutic Implications Content: COVID-19 is viral respiratory infection with frequently fatal lung complications in the elderly or in people with serious comorbidities. Lung destruction appears to be associated with a cytokine storm related to an increased level of interleukin-6 (IL6). Therapeutic targeting of the interleukin-6 signaling pathway can attenuate such a cytokine storm and can be beneficial for patients with COVID-19 in danger of pulmonary failure. This article demonstrates the importance of IL6 in progression of disease and the possibility of inhibition of IL6 signaling in COVID-19 therapy.

Title: Storm, typhoon, cyclone or hurricane in patients with COVID-19? Beware of the same storm that has a different origin Content: Some of the articles being published during the severe acute respiratory syndrome–coronavirus (SARS-CoV)-2 pandemic highlight a link between severe forms of coronavirus disease 2019 (COVID-19) and the so-called cytokine storm, also with increased ferritin levels. However, this scenario is more complex than initially thought due to the heterogeneity of hyperinflammation. Some patients with coronavirus 2019 disease (COVID-19) develop a fully blown secondary haemophagocytic lymphohistiocytosis (sHLH), whereas others, despite a consistent release of pro-inflammatory cytokines, do not fulfil sHLH criteria but still show some features resembling the phenotype of the hyperferritinemic syndrome. Despite the final event (the cytokine storm) is shared by various conditions leading to sHLH, the aetiology, either infectious, autoimmune or neoplastic, accounts for the differences in the various phases of this process. Moreover, the evidence of a hyperinflammatory microenvironment provided the rationale to employ immunomodulating agents for therapeutic purposes in severe COVID-19. This viewpoint aims at discussing the pitfalls and issues to be considered with regard to the use of immunomodulating agents in COVID-19, such as timing of treatment based on the viral load and the extent of cytokine/ferritin overexpression. Furthermore, it encompasses recent findings in the paediatric field about a novel multisystem inflammatory disease resembling toxic shock syndrome and atypical Kawasaki disease observed in children with proven SARS-CoV2 infection. Finally, it includes arguments in favour of adding COVID-19 to the spectrum of the recently defined ‘hyperferritinemic syndrome’, which already includes adult-onset Still’s disease, macrophage activation syndrome, septic shock and catastrophic anti-phospholipid syndrome.

Title: Amelioration of COVID-19 related cytokine storm syndrome: Parallels to chimeric antigen receptor-T cell cytokine release syndrome Content: Coronavirus disease-2019 (COVID-19) severity appears to parallel the host immune response, with a subset of patients developing COVID-19 cytokine storm syndrome (CSS).(1) Serum inflammatory cytokines are elevated in COVID-19,(2-5) and interleukin (IL)-6 appears to play a central role in COVID-19 related CSS.(6-8) Based on the success of IL-6 receptor blockade for chimeric antigen receptor T-cell therapy associated cytokine release syndrome (CAR T-cell CRS), similar strategies using tocilizumab are being investigated in COVID-19.

Title: [Expert consensus on Corona Virus Disease 2019 with special blood purification technology] Content: The outbreak of Corona Virus Disease 2019 (COVID-19) has spread to more than 70 countries worldwide and there was a higher mortality in those who developed serious illness.Cytokine storm syndrome is an important pathophysiological basis for COVID-19 patients developing into severe or critical conditions. It was indicated in the diagnosis and treatment scheme, by the National Health Commission of the People's Republic of China, that blood purifications such as plasma exchange, plasma adsorption, hemoperfusion, hemofiltration and plasmafiltration could be considered for use in the critical patients with cytokine storm syndrome. This expert consensus, proposed by the Chinese Society of Nephrology and the Nephrology Committee of Chinese Research Hospital Association, is to guide and standardize the clinical application of blood purifications in the treatment of severe or critical patients with COVID-19.

Title: [Expert consensus on Corona Virus Disease 2019 with special blood purification technology]. Content: The outbreak of Corona Virus Disease 2019 (COVID-19) has spread to more than 70 countries worldwide and there was a higher mortality in those who developed serious illness.Cytokine storm syndrome is an important pathophysiological basis for COVID-19 patients developing into severe or critical conditions. It was indicated in the diagnosis and treatment scheme, by the National Health Commission of the People's Republic of China, that blood purifications such as plasma exchange, plasma adsorption, hemoperfusion, hemofiltration and plasmafiltration could be considered for use in the critical patients with cytokine storm syndrome. This expert consensus, proposed by the Chinese Society of Nephrology and the Nephrology Committee of Chinese Research Hospital Association, is to guide and standardize the clinical application of blood purifications in the treatment of severe or critical patients with COVID-19.

Title: Profiling serum cytokines in COVID-19 patients reveals IL-6 and IL-10 are disease severity predictors. Content: Since the outbreak of coronavirus disease 2019 (COVID-19) in Wuhan, China, it has rapidly spread across many other countries. While the majority of patients were considered mild, critically ill patients involving respiratory failure and multiple organ dysfunction syndrome are not uncommon, which could result death. We hypothesized that cytokine storm is associated with severe outcome. We enrolled 102 COVID-19 patients who were admitted to Renmin Hospital (Wuhan, China). All patients were classified into moderate, severe and critical groups according to their symptoms. 45 control samples of healthy volunteers were also included. Inflammatory cytokines and C-Reactive Protein (CRP) profiles of serum samples were analyzed by specific immunoassays. Results showed that COVID-19 patients have higher serum level of cytokines (TNF-α, IFN-γ, IL-2, IL-4, IL-6 and IL-10) and CRP than control individuals. Within COVID-19 patients, serum IL-6 and IL-10 levels are significantly higher in critical group (n = 17) than in moderate (n = 42) and severe (n = 43) group. The levels of IL-10 is positively correlated with CRP amount (r = 0.41, P < 0.01). Using univariate logistic regression analysis, IL-6 and IL-10 are found to be predictive of disease severity and receiver operating curve analysis could further confirm this result (AUC = 0.841, 0.822 respectively). Our result indicated higher levels of cytokine storm is associated with more severe disease development. Among them, IL-6 and IL-10 can be used as predictors for fast diagnosis of patients with higher risk of disease deterioration. Given the high levels of cytokines induced by SARS-CoV-2, treatment to reduce inflammation-related lung damage is critical.

Title: The possible pathophysiology mechanism of cytokine storm in elderly adults with COVID-19 infection: the contribution of "inflame-aging" Content: PURPOSE: Novel Coronavirus disease 2019 (COVID-19), is an acute respiratory distress syndrome (ARDS), which is emerged in Wuhan, and recently become worldwide pandemic. Strangely, ample evidences have been shown that the severity of COVID-19 infections varies widely from children (asymptomatic), adults (mild infection), as well as elderly adults (deadly critical). It has proven that COVID-19 infection in some elderly critical adults leads to a cytokine storm, which is characterized by severe systemic elevation of several pro-inflammatory cytokines. Then, a cytokine storm can induce edematous, ARDS, pneumonia, as well as multiple organ failure in aged patients. It is far from clear till now why cytokine storm induces in only COVID-19 elderly patients, and not in young patients. However, it seems that aging is associated with mild elevated levels of local and systemic pro-inflammatory cytokines, which is characterized by "inflamm-aging". It is highly likely that "inflamm-aging" is correlated to increased risk of a cytokine storm in some critical elderly patients with COVID-19 infection. METHODS: A systematic search in the literature was performed in PubMed, Scopus, Embase, Cochrane Library, Web of Science, as well as Google Scholar pre-print database using all available MeSH terms for COVID-19, Coronavirus, SARS-CoV-2, senescent cell, cytokine storm, inflame-aging, ACE2 receptor, autophagy, and Vitamin D. Electronic database searches combined and duplicates were removed. RESULTS: The aim of the present review was to summarize experimental data and clinical observations that linked the pathophysiology mechanisms of "inflamm-aging", mild-grade inflammation, and cytokine storm in some elderly adults with severe COVID-19 infection.

Title: Weathering the Cytokine Storm in COVID-19: Therapeutic Implications Content: BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recently emerged in Wuhan, Hubei-China, as responsible for the coronavirus disease 2019 (COVID-19) and then spread rapidly worldwide. While most individuals remain asymptomatic or develop only mild symptoms, approximately 5% develop severe forms of COVID-19 characterized by acute respiratory distress syndrome (ARDS) and multiple-organ failure (MOF) that usually require intensive-care support and often yield a poor prognosis. SUMMARY: The pathophysiology of COVID-19 is far from being completely understood, and the lack of effective treatments leads to a sense of urgency to develop new therapeutic strategies based on pathophysiological assumptions. The exaggerated cytokine release in response to viral infection, a condition known as cytokine release syndrome (CRS) or cytokine storm, is emerging as the mechanism leading to ARDS and MOF in COVID-19, thus endorsing the hypothesis that properly timed anti-inflammatory therapeutic strategies could improve patients' clinical outcomes and prognosis. KEY MESSAGES: The objective of this article is to explore and comment on the potential role of the promising immunomodulatory therapies using pharmacological and nonpharmacological approaches to overcome the dysregulated proinflammatory response in COVID-19.

Title: Weathering the Cytokine Storm in COVID-19: Therapeutic Implications Content: BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) recently emerged in Wuhan, Hubei-China, as responsible for the coronavirus disease 2019 (COVID-19) and then spread rapidly worldwide. While most individuals remain asymptomatic or develop only mild symptoms, approximately 5% develop severe forms of COVID-19 characterized by acute respiratory distress syndrome (ARDS) and multiple-organ failure (MOF) that usually require intensive-care support and often yield a poor prognosis. SUMMARY: The pathophysiology of COVID-19 is far from being completely understood, and the lack of effective treatments leads to a sense of urgency to develop new therapeutic strategies based on pathophysiological assumptions. The exaggerated cytokine release in response to viral infection, a condition known as cytokine release syndrome (CRS) or cytokine storm, is emerging as the mechanism leading to ARDS and MOF in COVID-19, thus endorsing the hypothesis that properly timed anti-inflammatory therapeutic strategies could improve patients' clinical outcomes and prognosis. Key Messages: The objective of this article is to explore and comment on the potential role of the promising immunomodulatory therapies using pharmacological and nonpharmacological approaches to overcome the dysregulated proinflammatory response in COVID-19.

Title: Bilateral anterior uveitis as a part of a multisystem inflammatory syndrome secondary to COVID‐19 infection Content: During the ongoing COVID‐19 pandemic, there is a global concern about patients presenting with inflammatory syndrome with variable clinical features. Colanfrancesco et al. described COVID‐19 systemic inflammatory reaction that are characterized by a life‐threatening hyper‐inflammation sustained by a cytokines storm which eventually leads to multi‐organ failure. This article is protected by copyright. All rights reserved.

Title: Baricitinib, a drug with potential effect to prevent SARS-COV-2 from entering target cells and control cytokine storm induced by COVID-19 Content: In December 2019, a novel coronavirus pneumonia (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) suddenly broke out in China and rapidly spread all over the world. Recently, a cell surface protein, known as angiotensin-converting enzyme II (ACE2), has been identified to be involved in receptor-mediated endocytosis for SARS-CoV-2 entry to the cells. Many studies have reported the clinical characteristics of COVID-19: sudden deterioration of disease around 1-2 weeks after onset; much lower level of lymphocytes, especially natural killer (NK) cells in peripheral blood; extremely high pro-inflammatory cytokines and C reactive protein (CRP). About 15.7% of patients develop severe pneumonia, and cytokine storm is an important factor leading to rapid disease progression. Currently, there are no specific drugs for COVID-19 and the cytokine storm it causes. Baricitinib intracellularly inhibits the proinflammatory signal of several cytokines by suppressing Janus kinase (JAK) JAK1/JAK2. It has been demonstrated clinical benefits for the patients with rheumatoid arthritis (RA), active systemic lupus erythematosus and atopic dermatitis with good efficacy and safety records. Baricitinib is expected to interrupt the passage and intracellular assembly of SARS-CoV-2 into the target cells mediated by ACE2 receptor, and treat cytokine storm caused by COVID-19. Several clinical trials are currently investigating the drug, and one of which has been completed with encouraging results. In this paper, we will elaborate the role of cytokine storm mediated by JAK-STAT pathway in severe COVID-19, the possible mechanisms of baricitinib on reducing the viral entry into the target cells and cytokine storm, the key points of pharmaceutical care based on the latest research reports, clinical trials progress and drug instruction from the US FDA, so as to provide reference for the treatment of severe 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: Profiling serum cytokines in COVID-19 patients reveals IL-6 and IL-10 are disease severity predictors Content: Since the outbreak of coronavirus disease 2019 (COVID-19) in Wuhan, China, it has rapidly spread across many other countries. While the majority of patients were considered mild, critically ill patients involving respiratory failure and multiple organ dysfunction syndrome are not uncommon, which could result death. We hypothesized that cytokine storm is associated with severe outcome. We enrolled 102 COVID-19 patients who were admitted to Renmin Hospital (Wuhan, China). All patients were classified into moderate, severe and critical groups according to their symptoms. 45 control samples of healthy volunteers were also included. Inflammatory cytokines and C-Reactive Protein (CRP) profiles of serum samples were analyzed by specific immunoassays. Results showed that COVID-19 patients have higher serum level of cytokines (TNF-α, IFN-Î³, IL-2, IL-4, IL-6 and IL-10) and CRP than control individuals. Within COVID-19 patients, serum IL-6 and IL-10 levels are significantly higher in critical group (n = 17) than in moderate (n = 42) and severe (n = 43) group. The levels of IL-10 is positively correlated with CRP amount (r = 0.41, P < 0.01). Using univariate logistic regression analysis, IL-6 and IL-10 are found to be predictive of disease severity and receiver operating curve analysis could further confirm this result (AUC = 0.841, 0.822 respectively). Our result indicated higher levels of cytokine storm is associated with more severe disease development. Among them, IL-6 and IL-10 can be used as predictors for fast diagnosis of patients with higher risk of disease deterioration. Given the high levels of cytokines induced by SARS-CoV-2, treatment to reduce inflammation-related lung damage is critical.

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: Immune Status of COVID-19 Patients with Reference to SARS and MERS Content: During this global pandemic of COVID-19 infection, it became well known that morbidity and mortality is especially high at the extreme of life especially in certain racial or ethnic groups like Americans and Africans This is presumed due to low immunity associated with other comorbid conditions like diabetes, hypertension, cardiovascular disease, obesity and metabolic syndrome But the information available on the immune status of COVID-19 patients is limited Attempts must be made to enhance our understanding of the immune status of COVID-19 patients by revisiting our knowledge on the immune mechanisms of already known coronaviruses such as SARS-CoV and MERS-CoV Early elevation of the serum levels of pro-inflammatory cytokines observed in SARS and MERS infection suggests a possible same type of cytokine storm-mediated lung damage in COVID-19 patients too Dysregulation of interferon-1 response and downstream cascade in initial innate immune response at virus entry point has been related to lethal pneumonia in COVID-19 patients Adaptive response of increased CD8+ levels in COVID-19 patients seems to be useful in mild cases where it causes deteriorating effects in progressed severe disease patients resulting in destruction of type 2 pneumocytes hence inability to regenerate the alveolar epithelium A phenomenon called cytokine storm activates violent immunological reactions in the lung tissue resulting in ARDS followed by multiple organ system damages in COVID-19 patients Several immune evading mechanisms are thought to be employed by severe respiratory syndrome virus-2 (SARS-CoV-2) that might have resulted in its extremely increased contagiousness probably related with its frequent RNA mutations Failure to develop adequate virus limiting immune reactions by some cured patients warrant monitoring of all recovered patients This rapid mini review is aimed to enhance our knowledge of the immune status of COVID-19 infected patients with reference to SARS-CoV and MERS-CoV

Title: COVID-19: Pathogenesis, cytokine storm and therapeutic potential of interferons Content: ABSTRACT The outbreak of the novel SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) responsible for coronavirus disease 2019 (COVID-19) has developed into a major health hazard across the globe. The rapid escalation of the COVID-19 and the considerable associated illness leading to death has transformed it into a critical global public health issue. The current clinical investigation in patients with COVID-19 has showed strong upregulation of cytokine and interferon production after critical infection with SARS-CoV2- induced pneumonia. The current research suggests that few groups of patients with COVID-19 might have a cytokine storm syndrome. Thus, identification and treatment of hyperinflammation using existing, approved therapies with proven safety profiles to address the immediate need to reduce the rising mortality. To date, no specific therapeutic drug or vaccine has been discovered to treat this COVID-19. Intensive research is in progress to identify a promising drug therapy. Hence, several options were proposed to control this fast-emerging pandemic, including antiviral drugs, vaccines, small-molecules, monoclonal antibodies, oligonucleotides, peptides, and interferons (IFNs).

Title: Understanding the COVID‐19 coagulopathy spectrum Content: The SARS‐Cov‐2 (COVID‐19) pandemic has already claimed over 200,000 lives. Quite early on in this pandemic, it was recognised that the virus triggers the immune system leading to a cytokine storm in some severely ill patients [1]. This hyper‐responsiveness has been suggested to be the predominant aetiology for clinical deterioration and mortality in patients with this infection [2]. More recently, there have been several reports of increased thrombotic events in these patients [3‐6]. From a laboratory perspective, this hypercoagulability is reflected in the marked elevation of the fibrinolytic marker, D‐dimer, in almost all hospitalised COVID‐19 patients [7]. We must, therefore, ask ourselves what is the link between the extremes of the immune system, presenting as cytokine storm, and the extremes of coagulation, presenting as arterial and venous thromboembolism?

Title: Biosensors for Managing the COVID-19 Cytokine Storm: Challenges Ahead Content: The global COVID-19 pandemic has oversaturated many intensive care units to the point of collapse, leading to enormous spikes in death counts. Before critical care becomes a necessity, identifying patients who are likely to become critically ill and providing prompt treatment is a strategy to avoid ICU oversaturation. There is a consensus that a hyperinflammatory syndrome or a "cytokine storm" is responsible for poor outcomes in COVID-19. Measuring cytokine levels at the point of care is required in order to better understand this process. In this Perspective, we summarize the main events behind the cytokine storm in COVID-19 as well as current experimental treatments. We advocate for a new biosensor-enabled paradigm to personalize the management of COVID-19 and stratify patients. Biosensor-guided dosing and timing of immunomodulatory therapies could maximize the benefits of these anti-inflammatory treatments while minimizing deleterious effects. Biosensors will also be essential in order to detect complications such as coinfections and sepsis, which are common in immunosuppressed patients. Finally, we propose the ideal features of these biosensors using some prototypes from the recent literature as examples. Multisensors, lateral flow tests, mobile biosensors, and wearable biosensors are seen as key players for precision medicine in COVID-19.

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: SARS-CoV-2: Viral Mechanisms and Possible Therapeutic Targets - What to learn from Rheumatologists? Content: It was with great interest that we read the letter from Randy Cron and collaborators (1) linking the cytokine storm syndrome (CSS) seen in macrophage activation syndrome, common in the rheumatological setting, with the CSS postulated to be a background in the novel coronavirus (SARS-CoV-2) infection. Amid the high contagiousness of the virus, science was also infected by an infodemia, compelled to enter a race to find effective therapies studying mechanisms molecular aspects of SARS-CoV-2 concomitant to urgent bedside manage of patients.

Title: The possible pathophysiology mechanism of cytokine storm in elderly adults with COVID-19 infection: the contribution of “inflame-aging” Content: PURPOSE: Novel Coronavirus disease 2019 (COVID-19), is an acute respiratory distress syndrome (ARDS), which is emerged in Wuhan, and recently become worldwide pandemic. Strangely, ample evidences have been shown that the severity of COVID-19 infections varies widely from children (asymptomatic), adults (mild infection), as well as elderly adults (deadly critical). It has proven that COVID-19 infection in some elderly critical adults leads to a cytokine storm, which is characterized by severe systemic elevation of several pro-inflammatory cytokines. Then, a cytokine storm can induce edematous, ARDS, pneumonia, as well as multiple organ failure in aged patients. It is far from clear till now why cytokine storm induces in only COVID-19 elderly patients, and not in young patients. However, it seems that aging is associated with mild elevated levels of local and systemic pro-inflammatory cytokines, which is characterized by “inflamm-aging”. It is highly likely that “inflamm-aging” is correlated to increased risk of a cytokine storm in some critical elderly patients with COVID-19 infection. METHODS: A systematic search in the literature was performed in PubMed, Scopus, Embase, Cochrane Library, Web of Science, as well as Google Scholar pre-print database using all available MeSH terms for COVID-19, Coronavirus, SARS-CoV-2, senescent cell, cytokine storm, inflame-aging, ACE2 receptor, autophagy, and Vitamin D. Electronic database searches combined and duplicates were removed. RESULTS: The aim of the present review was to summarize experimental data and clinical observations that linked the pathophysiology mechanisms of “inflamm-aging”, mild-grade inflammation, and cytokine storm in some elderly adults with severe COVID-19 infection.

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: Potential Immunotherapeutic Targets For Hypoxia Due to COVI-FLU Content: The world is currently embroiled in a pandemic of coronavirus disease 2019 (COVID-19), a respiratory illness caused by the novel betacoronavirus SARS-CoV-2. The severity of COVID-19 disease ranges from asymptomatic to fatal acute respiratory distress syndrome (ARDS). In few patients, the disease undergoes phenotypic differentiation between 7-14 days of acute illness, either resulting in full recovery or symptom escalation. However, the mechanism of such variation is not clear, but the facts suggest that patient's immune status, co-morbidities, and the systemic effects of the viral infection (potentially depending on the SARS-CoV-2 strain involved) play a key role. Subsequently, patients with the most severe symptoms tend to have poor outcomes, manifest severe hypoxia, and possess elevated levels of pro-inflammatory cytokines (including IL-1ß, IL-6, IFN-Î³, and TNF-α) along with elevated levels of the anti-inflammatory cytokine IL-10, marked lymphopenia, and elevated neutrophil-to-lymphocyte ratios. Based on the available evidence, we propose a mechanism wherein SARS-CoV-2 infection induces direct organ damage while also fueling an IL-6-mediated cytokine release syndrome (CRS) and hypoxia, resulting in escalating systemic inflammation, multi-organ damage, and end-organ failure. Elevated IL-6 and hypoxia together predisposes patients to pulmonary hypertension, and the presence of asymptomatic hypoxia in COVID-19 further compounds this problem. Due to the similar downstream mediators, we discuss the potential synergistic effects and systemic ramifications of SARS-CoV-2 and influenza virus during co-infection, a phenomenon we have termed "COVI-Flu." Additionally, the differences between CRS and cytokine storm are highlighted. Finally, novel management approaches, clinical trials, and therapeutic strategies toward both SARS-CoV-2 and COVI-Flu infection are discussed, highlighting host response optimization and systemic inflammation reduction.

Title: Potential Immunotherapeutic Targets For Hypoxia Due to COVI-FLU. Content: The world is currently embroiled in a pandemic of coronavirus disease 2019 (COVID-19), a respiratory illness caused by the novel betacoronavirus SARS-CoV-2. The severity of COVID-19 disease ranges from asymptomatic to fatal acute respiratory distress syndrome (ARDS). In few patients, the disease undergoes phenotypic differentiation between 7-14 days of acute illness, either resulting in full recovery or symptom escalation. However, the mechanism of such variation is not clear, but the facts suggest that patient's immune status, co-morbidities, and the systemic effects of the viral infection (potentially depending on the SARS-CoV-2 strain involved) play a key role. Subsequently, patients with the most severe symptoms tend to have poor outcomes, manifest severe hypoxia, and possess elevated levels of pro-inflammatory cytokines (including IL-1β, IL-6, IFN-γ, and TNF-α) along with elevated levels of the anti-inflammatory cytokine IL-10, marked lymphopenia, and elevated neutrophil-to-lymphocyte ratios. Based on the available evidence, we propose a mechanism wherein SARS-CoV-2 infection induces direct organ damage while also fueling an IL-6-mediated cytokine release syndrome (CRS) and hypoxia, resulting in escalating systemic inflammation, multi-organ damage, and end-organ failure. Elevated IL-6 and hypoxia together predisposes patients to pulmonary hypertension, and the presence of asymptomatic hypoxia in COVID-19 further compounds this problem. Due to the similar downstream mediators, we discuss the potential synergistic effects and systemic ramifications of SARS-CoV-2 and influenza virus during co-infection, a phenomenon we have termed "COVI-Flu." Additionally, the differences between CRS and cytokine storm are highlighted. Finally, novel management approaches, clinical trials, and therapeutic strategies toward both SARS-CoV-2 and COVI-Flu infection are discussed, highlighting host response optimization and systemic inflammation reduction.

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: 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: 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: 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: Can we use interleukin-6 (IL-6) blockade for coronavirus disease 2019 (COVID-19)-induced cytokine release syndrome (CRS)? Content: The emergent outbreak of coronavirus disease 2019 (COVID-19) has caused a global pandemic. Acute respiratory distress syndrome (ARDS) and multiorgan dysfunction are among the leading causes of death in critically ill patients with COVID-19. The elevated inflammatory cytokines suggest that a cytokine storm, also known as cytokine release syndrome (CRS), may play a major role in the pathology of COVID-19. However, the efficacy of corticosteroids, commonly utilized antiinflammatory agents, to treat COVID-19-induced CRS is controversial. There is an urgent need for novel therapies to treat COVID-19-induced CRS. Here, we discuss the pathogenesis of severe acute respiratory syndrome (SARS)-induced CRS, compare the CRS in COVID-19 with that in SARS and Middle East respiratory syndrome (MERS), and summarize the existing therapies for CRS. We propose to utilize interleukin-6 (IL-6) blockade to manage COVID-19-induced CRS and discuss several factors that should be taken into consideration for its clinical application.

Title: Amelioration of COVID‐19 related cytokine storm syndrome: Parallels to chimeric antigen receptor‐T cell cytokine release syndrome Content: Coronavirus disease‐2019 (COVID‐19) severity appears to parallel the host immune response, with a subset of patients developing COVID‐19 cytokine storm syndrome (CSS).(1) Serum inflammatory cytokines are elevated in COVID‐19,(2–5) and interleukin (IL)‐6 appears to play a central role in COVID‐19 related CSS.(6–8) Based on the success of IL‐6 receptor blockade for chimeric antigen receptor T‐cell therapy associated cytokine release syndrome (CAR T‐cell CRS), similar strategies using tocilizumab are being investigated in COVID‐19.

Title: The COVID-19 Cytokine Storm; What We Know So Far Content: COVID-19 is a rapidly spreading global threat that has been declared as a pandemic by the WHO. COVID-19 is transmitted via droplets or direct contact and infects the respiratory tract resulting in pneumonia in most of the cases and acute respiratory distress syndrome (ARDS) in about 15 % of the cases. Mortality in COVID-19 patients has been linked to the presence of the so-called “cytokine storm” induced by the virus. Excessive production of proinflammatory cytokines leads to ARDS aggravation and widespread tissue damage resulting in multi-organ failure and death. Targeting cytokines during the management of COVID-19 patients could improve survival rates and reduce mortality.

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: The compelling arguments for the need of microvascular investigation in COVID-19 critical patients Content: The burden of pandemic COVID-19 is growing worldwide, as the continuous increases of contagion. Only 10-15% of the entire infected population has the necessity of intensive care unit (ICU) treatments. But, this relatively low rate of patients has absorbed almost the whole availability of ICU during few days, becoming at least in Italy, an emergency for the national health system. In COVID-19 ICU patients massive aggression of lung with severe pulmonary failure, as well as kidney and liver injuries, heart, brain, bowel and spleen damages with lymph nodes necrosis and even cutaneous manifestations have been observed. Moreover, increased levels of cytokines so-called "cytokines storm (CS), and overt intravascular disseminated coagulation have been also reported. The hypercoagulation and CS would speculate about a microvascular dysfunction. Unfortunately, no specific observations have been performed on microcirculatory dysfunction in COVID-19 patients. Hence the presumed pathophysiological pathways and models about a microvascular involvement can be gathered by sepsis models studies. But despite this lack of evidence, the COVID-19 has emphasized the compelling need for microcirculation monitoring at the bedside in ICU patients.

Title: The compelling arguments for the need for microvascular investigation in COVID-19 critical patients. Content: The burden of pandemic COVID-19 is growing worldwide, as the continuous increases of contagion. Only 10-15% of the entire infected population has the necessity of intensive care unit (ICU) treatments. But, this relatively low rate of patients has absorbed almost the whole availability of ICU during few days, becoming at least in Italy, an emergency for the national health system. In COVID-19 ICU patients massive aggression of lung with severe pulmonary failure, as well as kidney and liver injuries, heart, brain, bowel and spleen damages with lymph nodes necrosis and even cutaneous manifestations have been observed. Moreover, increased levels of cytokines so-called "cytokines storm (CS), and overt intravascular disseminated coagulation have been also reported. The hypercoagulation and CS would speculate about a microvascular dysfunction. Unfortunately, no specific observations have been performed on microcirculatory dysfunction in COVID-19 patients. Hence the presumed pathophysiological pathways and models about a microvascular involvement can be gathered by sepsis models studies. But despite this lack of evidence, the COVID-19 has emphasized the compelling need for microcirculation monitoring at the bedside in ICU patients.

Title: High IL‐6/IFN‐γ ratio could be associated with severe disease in COVID‐19 patients Content: Cytokines are important mediators of the inflammatory response, and during infection with SARS‐CoV‐2 it has been suggested that there is a cytokine storm syndrome. In this study, a meta‐analysis was performed to investigate whether the IL‐6/IFN‐γ ratio can help predict clinical severity in patients with COVID‐19. This article is protected by copyright. All rights reserved.

Title: Biochemical indicators of coronavirus disease 2019 exacerbation and the clinical implications Content: Coronavirus Disease 2019 (COVID-19) has sparked a global pandemic, affecting more than 4 million people worldwide. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can cause acute lung injury (ALI) and even acute respiratory distress syndrome (ARDS); with a fatality of 7.0 %. Accumulating evidence suggested that the progression of COVID-19 is associated with lymphopenia and excessive inflammation, and a subset of severe cases might exhibit cytokine storm triggered by secondary hemophagocytic lymphohistiocytosis (sHLH). Furthermore, secondary bacterial infection may contribute to the exacerbation of COVID-19. We recommend using both IL-10 and IL-6 as the indicators of cytokine storm, and monitoring the elevation of procalcitonin (PCT) as an alert for initiating antibacterial agents. Understanding the dynamic progression of SARS-CoV-2 infection is crucial to determine an effective treatment strategy to reduce the rising mortality of this global pandemic.

Title: Pediatric Crohn's Disease and Multisystem Inflammatory Syndrome in Children (MIS-C) and COVID-19 Treated with Infliximab Content: Coronavirus disease 2019 (COVID-19) may lead to a severe inflammatory response referred to as a cytokine storm. We describe a case of severe COVID-19 infection in a recently diagnosed pediatric Crohn's disease patient successfully treated with Tumor Necrosis Factor-alpha (TNF-α) blockade. The patient presented with five days of fever, an erythematous maculopapular facial rash, and abdominal pain without respiratory symptoms. SARS-CoV-2 PCR was positive. Despite inpatient treatment for COVID-19 and a perianal abscess, the patient acutely decompensated, with worsening fever, tachycardia, fluid-refractory hypotension, elevation of liver enzymes, and transformation of the rash into purpura extending from the face to the trunk, upper and lower extremities, including the palmar and plantar surfaces of the hands and feet. Cytokine profile revealed rising levels of interleukin (IL)-6, IL-8, and TNF-α, higher than those described in either inflammatory bowel disease (IBD) or severe COVID-19 alone. The patient was treated with infliximab for TNF-α blockade to address both moderately to severely active Crohn's disease and multisystem inflammatory syndrome in children (MIS-C) temporally related to COVID-19. Within hours of infliximab treatment, fever, tachycardia and hypotension resolved. Cytokine profile improved with normalization of TNF-α, a decrease in IL-6, and IL-8 concentrations. This case supports a role for blockade of TNF-α in the treatment of COVID-19 inflammatory cascade. The role of anti-TNF agents in patients with MIS-C temporally related to COVID-19 requires further investigation.

Title: Coronavirus Disease 2019 (COVID-19): Cytokine Storms, Hyper-Inflammatory Phenotypes, and Acute Respiratory Distress Syndrome Content: Abstract Coronavirus Disease 2019 (COVID-19) was first identified in China at the end of 2019. Acute respiratory distress syndrome (ARDS) represents the most common and serious complication of COVID-19. Cytokine storms are a pathophysiological feature of COVID-19 and play an important role in distinguishing hyper-inflammatory subphenotypes of ARDS. Accordingly, in this review, we focus on hyper-inflammatory host responses in ARDS that play a critical role in the differentiated development of COVID-19. Furthermore, we discuss inflammation-related indicators that have the potential to identify hyper-inflammatory subphenotypes of COVID-19, especially for those with a high risk of ARDS. Finally, we explore the possibility of improving the quality of monitoring and treatment of COVID-19 patients and in reducing the incidence of critical illness and mortality via better distinguishing hyper- and hypo-inflammatory subphenotypes of COVID-19.

Title: The COVID-19 Cytokine Storm; What We Know So Far Content: COVID-19 is a rapidly spreading global threat that has been declared as a pandemic by the WHO. COVID-19 is transmitted via droplets or direct contact and infects the respiratory tract resulting in pneumonia in most of the cases and acute respiratory distress syndrome (ARDS) in about 15 % of the cases. Mortality in COVID-19 patients has been linked to the presence of the so-called "cytokine storm" induced by the virus. Excessive production of proinflammatory cytokines leads to ARDS aggravation and widespread tissue damage resulting in multi-organ failure and death. Targeting cytokines during the management of COVID-19 patients could improve survival rates and reduce mortality.

Title: Could hemophagocytic lymphohistiocytosis be the core issue of severe COVID-19 cases? Content: BACKGROUND: COVID-19, a disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), commonly presents as fever, cough, dyspnea, and myalgia or fatigue. Although the majority of patients with COVID-19 have mild symptoms, some are more prone to serious outcomes, including pneumonia, acute respiratory distress syndrome (ARDS), and even death. Hemophagocytic lymphohistiocytosis (HLH) is a severe, life-threatening inflammatory syndrome associated with intense cytokine release (also known as a “cytokine storm”). Similar to COVID-19, HLH is characterized by aggressive course leading to multi-organ failure. MAIN TEXT: The purpose of this review article is to draw attention to the possibility of the complication of HLH in patients with the severe course of COVID-19. Indeed, some of the clinical characteristics observed in the more severe cases of COVID-19 are reminiscent of secondary HLH (which can be triggered by infections, malignancies, rheumatological diseases, or autoimmune/immunodeficiency conditions). The pathogenesis of SARS-CoV-2 infection also suggests that HLH or a similar hyperinflammatory syndrome is the cause of the severe course of the infection. CONCLUSION: The pathogenesis and clinical symptoms of severe COVID-19 indicate that an increased inflammatory response corresponding to HLH is occurring. Therefore, patients with severe COVID-19 should be screened for hyperinflammation using standard laboratory tests to identify those for whom immunosuppressive therapy may improve outcomes.

Title: Can we use interleukin-6 (IL-6) blockade for coronavirus disease 2019 (COVID-19)-induced cytokine release syndrome (CRS)? Content: Abstract The emergent outbreak of coronavirus disease 2019 (COVID-19) has caused a global pandemic. Acute respiratory distress syndrome (ARDS) and multiorgan dysfunction are among the leading causes of death in critically ill patients with COVID-19. The elevated inflammatory cytokines suggest that a cytokine storm, also known as cytokine release syndrome (CRS), may play a major role in the pathology of COVID-19. However, the efficacy of corticosteroids, commonly utilized antiinflammatory agents, to treat COVID-19-induced CRS is controversial. There is an urgent need for novel therapies to treat COVID-19-induced CRS. Here, we discuss the pathogenesis of severe acute respiratory syndrome (SARS)-induced CRS, compare the CRS in COVID-19 with that in SARS and Middle East respiratory syndrome (MERS), and summarize the existing therapies for CRS. We propose to utilize interleukin-6 (IL-6) blockade to manage COVID-19-induced CRS and discuss several factors that should be taken into consideration for its clinical application.

Title: Cytokine storm in COVID-19: pathogenesis and overview of anti-inflammatory agents used in treatment Content: COVID-19 infection has a heterogenous disease course; it may be asymptomatic or causes only mild symptoms in the majority of the cases, while immunologic complications such as macrophage activation syndrome also known as secondary hemophagocytic lymphohistiocytosis, resulting in cytokine storm syndrome and acute respiratory distress syndrome, may also occur in some patients. According to current literature, impairment of SARS-CoV-2 clearance due to genetic and viral features, lower levels of interferons, increased neutrophil extracellular traps, and increased pyroptosis and probable other unknown mechanisms create a background for severe disease course complicated by macrophage activation syndrome and cytokine storm. Various genetic mutations may also constitute a risk factor for severe disease course and occurrence of cytokine storm in COVID-19. Once, immunologic complications like cytokine storm occur, anti-viral treatment alone is not enough and should be combined with appropriate anti-inflammatory treatment. Anti-rheumatic drugs, which are tried for managing immunologic complications of COVID-19 infection, will also be discussed including chloroquine, hydroxychloroquine, JAK inhibitors, IL-6 inhibitors, IL-1 inhibitors, anti-TNF-α agents, corticosteroids, intravenous immunoglobulin (IVIG), and colchicine. Early recognition and appropriate treatment of immunologic complications will decrease the morbidity and mortality in COVID-19 infection, which requires the collaboration of infectious disease, lung, and intensive care unit specialists with other experts such as immunologists, rheumatologists, and hematologists.

Title: COVID 19: a clue from innate immunity Content: The recent COVID-19 pandemic has had a significant impact on our lives and has rapidly expanded to reach more than 4 million cases worldwide by May 2020. These cases are characterized by extreme variability, from a mild or asymptomatic form lasting for a few days up to severe forms of interstitial pneumonia that may require ventilatory therapy and can lead to patient death. Several hypotheses have been drawn up to understand the role of the interaction between the infectious agent and the immune system in the development of the disease and the most severe forms; the role of the cytokine storm seems important. Innate immunity, as one of the first elements of guest interaction with different infectious agents, could play an important role in the development of the cytokine storm and be responsible for boosting more severe forms. Therefore, it seems important to study also this important arm of the immune system to adequately understand the pathogenesis of the disease. Research on this topic is also needed to develop therapeutic strategies for treatment of this disease.

Title: COVID 19: a clue from innate immunity Content: The recent COVID-19 pandemic has had a significant impact on our lives and has rapidly expanded to reach more than 4 million cases worldwide by May 2020. These cases are characterized by extreme variability, from a mild or asymptomatic form lasting for a few days up to severe forms of interstitial pneumonia that may require ventilatory therapy and can lead to patient death.Several hypotheses have been drawn up to understand the role of the interaction between the infectious agent and the immune system in the development of the disease and the most severe forms; the role of the cytokine storm seems important.Innate immunity, as one of the first elements of guest interaction with different infectious agents, could play an important role in the development of the cytokine storm and be responsible for boosting more severe forms. Therefore, it seems important to study also this important arm of the immune system to adequately understand the pathogenesis of the disease. Research on this topic is also needed to develop therapeutic strategies for treatment of this disease.

Title: Changing dynamics of psychoneuroimmunology during COVID-19 pandemic Content: The Coronavirus Disease-2019 (COVID-19) pandemic has led to a global health care crisis in recent times. Emerging research suggest an unanticipated impact of COVID-19 on mental and/or psychological health of both the general community and affected individuals. The fear of the COVID-19 epidemic and the consequent lockdown and economic crisis has led to globally increased psychological distress. The biological bases of immediate and new onset of psychiatric symptoms in individuals with COVID-19 are not yet known. COVID-19 infection may lead to activated immune-inflammatory pathways and cytokine storm. Activated immune-inflammatory pathways, especially chronic low-grade inflammation, are associated with major psychiatric disorders in at least a subset of individuals. We propose that both the (sub)chronic inflammatory response and cytokine storm might crucially be involved in the immediate manifestation of neuropsychiatric symptoms in individuals with COVID-19 infection as well as heightened expression of psychiatric symptoms in COVID-19 infected individuals with prior psychiatric conditions. These events might expand concepts in psychoneuroimmunology, with the importance of chronic-low grade inflammation augmented by the cytokine storm hypothesis. Additionally, this might augment and refine diagnosis and prognostic management as well as treatment.

Title: Biosensors for Managing the COVID-19 Cytokine Storm: Challenges Ahead Content: [Image: see text] The global COVID-19 pandemic has oversaturated many intensive care units to the point of collapse, leading to enormous spikes in death counts. Before critical care becomes a necessity, identifying patients who are likely to become critically ill and providing prompt treatment is a strategy to avoid ICU oversaturation. There is a consensus that a hyperinflammatory syndrome or a “cytokine storm” is responsible for poor outcomes in COVID-19. Measuring cytokine levels at the point of care is required in order to better understand this process. In this Perspective, we summarize the main events behind the cytokine storm in COVID-19 as well as current experimental treatments. We advocate for a new biosensor-enabled paradigm to personalize the management of COVID-19 and stratify patients. Biosensor-guided dosing and timing of immunomodulatory therapies could maximize the benefits of these anti-inflammatory treatments while minimizing deleterious effects. Biosensors will also be essential in order to detect complications such as coinfections and sepsis, which are common in immunosuppressed patients. Finally, we propose the ideal features of these biosensors using some prototypes from the recent literature as examples. Multisensors, lateral flow tests, mobile biosensors, and wearable biosensors are seen as key players for precision medicine in 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: 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: Inflammation: A bridge between Diabetes and COVID-19, and possible management with sitagliptin Content: Patients with SARS-CoV-2 infections experience lymphopenia and inflammatory cytokine storms in the severe stage of the disease, leading to multi-organ damage. The exact pattern of immune system changes and their condition during the disease process is unclear. The available knowledge has indicated that the NF-kappa-B pathway, which is induced by several mediators, has a significant role in cytokine storm through the various mechanisms. Therefore, identifying the state of the immune cells and the dominant mechanisms for the production of cytokines incorporated in the cytokine storm can be a critical step in the therapeutic approach. On the other hand, some studies identified a higher risk for diabetic patients. Diabetes mellitus exhibits a close association with inflammation and increases the chance of developing COVID-19. Patients with diabetes mellitus have shown to have more virus entry, impaired immunity response, less viral elimination, and dysregulated inflammatory cytokines. The parallel analysis of COVID-19 and diabetes mellitus pathogenesis has proposed that the control of the inflammation through the interfering with the critical points of major signaling pathways may provide the new therapeutic approaches. In recent years, the role of Dipeptidyl Peptidase 4 (DPP4) in chronic inflammation has been proved. Numerous immune cells express the DPP4 protein. DPP4 regulates antibody production, cytokine secretion, and immunoglobulin class switching. DPP4 inhibitors like sitagliptin reduce inflammation intensity in different states. Following the accumulating data, we hypothesize that sitagliptin might reduce COVID-19 severity. Sitagliptin, an available DPP4 inhibitor drug, showed multidimensional anti-inflammatory effects among diabetic patients. It reduces the inflammation mostly by affecting on NF-kappa-B signaling pathway. Under the fact that inflammatory mediators are active in individuals with COVID-19, blocking the predominant pathway could be helpful.

Title: Traditional Chinese medicine for treatment of COVID-19 based on literature mining of targeting cytokine storm/ 基于干预细胞因子风暴文献挖掘的中医药治疗重症新型冠状病毒肺炎探讨 Content: The primary clinical manifestations of coronavirus disease 2019 (COVID-19) are fever, fatigue and dry cough. Several clinical studies reported that some patients with low or medium fever, or even without obvious symptom, rapidly progressed to severe or critical illness, including severe acute respiratory syndrome, septic shock, coagulation disorders and intractable metabolic acidosis. These patients were usually associated with significant elevated serum levels of a profile of cytokines, which is similar to SARS-2003 and MERS-2015, indicating the occurrence of cytokine storm. In the present review, we summarized previous advances in the treatment of severe cases of SARS by using traditional Chinese medicines (TCM), especially those TCM targeting cytokine storm, based on literature mining. By using data mining and network pharmacology, we also investigated underlying mechanisms and biological pathways involved in the inhibitory effects of TCM against cytokine storm. This review not only provides novel insights in the precise application of TCM, appropriate integrative use of TCM in combination with western medicine, but also contributes to the discovery of novel drugs or new therapeutic strategies targeting cytokine storm to suppress progression of COVID-19 and to improve clinical prognosis and outcomes.

Title: Cytokine Storm in COVID-19 patients transforms to a Cytokine Super Cyclone in patients with risk factors Content: The seventh human coronavirus SARS-CoV2 belongs to the cluster of extremely pathogenic coronaviruses like SARS-CoV and MERS-CoV, which are established to cause lower respiratory tract infection. The viral infection can be fatal as the disease advances to pneumonia followed by acute respiratory distress syndrome (ARDS). Increasingly higher cytokine concentration on account of over-stimulated immune response against the virus, or the ‘cytokine storm’, is the reason behind the manifestation of lethal clinical symptoms. In this article, we discuss the immune pathogenesis of cytokine storm and its relation with SARS-CoV2/COVID-19 risk factors. People with underlying risk factors are more susceptible to fatal complications of COVID-19 infection leading to poor clinical outcome. The increased pro-inflammatory immune status in patients with risk factors (diabetes, hypertension, cardiovascular disease, COPD) exacerbates the Cytokine-storm of COVID-19 to a Cytokine Super Cyclone. We also overviewed antiviral immune response provided by BCG vaccine involving the IL-1β, IL-6 and TNF-α secretion via ‘trained monocytes’, which confers early protection against SARS-CoV2.

Title: Rheumatologists and Pulmonologists at Temple University weather the COVID-19 storm together. Content: In recent commentaries from Lancet Rheumatology and The Journal of Rhuematology (1-2) the authors eloquently illustrated the connection between COVID-19 infection, the subsequent cytokine storm (CS) that ensues in a number of patients and the potential efficacy of biologics that Rheumatologists routinely use in their practices. Moreover those biologics were originally investigated by Rheumatologists for the treatment of numerous rheumatic conditions, including macrophage activating syndrome (MAS), a similar form of storm that resembles the one occurring in COVID-19 patients (3).

Title: Role of inflammatory markers in corona virus disease (COVID-19) patients: A review. Content: IMPACT STATEMENT In late 2019, a novel virus called SARS-CoV-2, expanded globally from Wuhan, China and was declared a pandemic on 11 March 2020 by the WHO. The mechanism of virus entry inside the host cell depends upon the cellular proteases including cathepsins, HAT, and TMPRSS2, which splits up the spike protein and causes further penetration. MERS coronavirus uses DPP4, while coronavirus HCoV-NL63 and SARS-CoV and SARS-CoV-2 employ ACE-2 as the key receptor. Cytokine storm syndrome was analyzed in critically ill nCOVID-19 patients and it is presented with high inflammatory mediators, systemic inflammation, and multiple organ failure. Among various inflammatory mediators, the level of interleukins (IL-2, IL-7, IL-10), G-CSF, MIP1A, MCP1, and TNF-α was reported to be higher in critically ill patients. Understanding this molecular mechanism of ILs, T cells, and dendritic cells will be helpful to design immunotherapy and novel drugs for the treatment of nCOVID-19 infection.

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: 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: The kidney in COVID-19: protagonist or figurant? Content: The etiology of injury in COVID-19 patients is diverse and multifactorial. Autopsy and biopsy studies reveal, alongside podocyte and tubular cell anomalies, the presence of virion within the cells. Evidence suggests that, in addition to the direct cytopathic effect of SARS- CoV2 on the glomeruli and renal tubules, there is also the indirect effect of cell-mediated immunity, the cytokines storm and the cross-talk between organs with possible systemic effects of the disease. These mechanisms are interconnected and have profound therapeutic implications involving extracorporeal removal of inflammatory cytokines. Dialysis patients, and children, in particular, should be classified as "at high risk" of contracting the disease. Infections are one of the most frequent causes of death in children with chronic renal failure who undergo dialysis. The reasons for this particular susceptibility are to be found in the compromised immune system, secondary to chronic malnutrition, immunosuppressive therapy, and uremia, frequent contact with healthcare personnel and other patients attending the dialysis unit and in need of the presence of other family members during treatment.