0f315ae2-b4c2-41d2-bcad-9af73252d1f3.json

{
 "id": "0f315ae2-b4c2-41d2-bcad-9af73252d1f3",
 "disease": {
  "id": "H00630",
  "names": [
   "Rheumatoid arthritis"
  ],
  "dbLinks": {
   "icd10": [
    "M05"
   ],
   "mesh": [
    "D001172"
   ]
  },
  "category": "Immune system disease",
  "description": "Rheumatoid arthritis (RA) is a common autoimmune disease that primarily manifests as chronic inflammatory arthropathy. Persistent synovitis leads to cartilage destruction, bone erosions and periarticular decalcification, subsequently resulting in impaired joint function. It is more common between the ages of 35 and 50 years, affecting three times more women than men. Susceptibility to RA is genetically determined with multiple genes contributing. Inheritance of HLA DRB1 alleles encoding a distinctive five-amino-acid sequence known as the \"shared epitope\" (SE) is the best characterized genetic risk factor. The mechanism by which the SE alleles contribute to the development of RA is not very clear. It has been postulated that the presence of these conserved sequences in the antigen-binding groove alters the way antigenic peptides are bound to and presented to T-cell lymphocytes. This, in turn, may trigger abnormal immune responses and lead to RA."
 },
 "article": {
  "id": "22736291",
  "text": "OBJECTIVE:\nTo examine the relationship of Porphyromonas gingivalis to the presence of autoantibodies in individuals at risk of rheumatoid arthritis (RA).\n\nMETHODS:\nStudy participants included the following: 1) a cohort enriched in subjects with HLA-DR4 and 2) subjects at risk of RA by virtue of having a first-degree relative with RA. None of the study subjects satisfied the American College of Rheumatology 1987 classification criteria for RA. Autoantibodies measured included anti-citrullinated protein antibody (ACPA; by second-generation anti-cyclic citrullinated peptide antibody enzyme-linked immunosorbent assay [ELISA]) and rheumatoid factor (RF; by nephelometry or ELISA for IgA, IgM, or IgG isotype). Individuals were considered autoantibody positive (n = 113) if they had ≥1 RA-related autoantibody; individuals were further categorized as high risk (n = 38) if they had ACPA or positive findings ≥2 assays for RF. Autoantibody-negative individuals (n = 171) served as a comparator group. Antibody to P gingivalis, P intermedia, and F nucleatum were measured. Associations of bacterial antibodies with group status were examined using logistic regression.\n\nRESULTS:\nAnti-P gingivalis concentrations were higher in high-risk (P = 0.011) and autoantibody positive group (P = 0.010) than in the autoantibody negative group. There were no group differences in anti-P intermedia or anti-F nucleatum concentrations. After multivariable adjustment, anti-P gingivalis concentrations (but not anti-P intermedia or anti-F nucleatum) were significantly associated with autoantibody-positive and high-risk status (P \u003c 0.05).\n\nCONCLUSION:\nImmunity to P gingivalis, but not P intermedia or F nucleatum, is significantly associated with the presence of RA-related autoantibodies in individuals at risk of RA. These results support the hypothesis that infection with P gingivalis may play a central role in the early loss of tolerance to self antigens that occurs in the pathogenesis of RA."
 },
 "questions": [
  {
   "id": "20386f3f-0817-445b-b7a7-6ad83e072bce",
   "text": "What are the risk factors of Rheumatoid arthritis?",
   "answers": [
    {
     "answer_start": 1179,
     "text": "Anti-P gingivalis concentrations"
    },
    {
     "answer_start": 1849,
     "text": "infection with P gingivalis"
    }
   ]
  }
 ]
}