musculoskeletal and connective tissue disorders
Rheumatoid Arthritis (RA)
Etiology of Rheumatoid Arthritis
Although rheumatoid arthritis involves autoimmune reactions, the precise cause is unknown; many factors may contribute. A genetic predisposition has been identified and, in White populations, localized to a shared epitope in the HLA-DRB1 locus of class II histocompatibility antigens. Unknown or unconfirmed environmental factors (eg, viral infections, cigarette smoking) are thought to play a role in triggering and maintaining joint inflammation. Risk factors for rheumatoid arthritis include the following: Smoking Obesity Sex hormones Drugs Changes in microbiome of the gut, mouth, and lung ( Etiology references ) Periodontal disease ( Periodontitis ) ( 1.Block KE, Zheng Z, Dent AL, et al: Gut microbiota regulates K/BxN autoimmune arthritis through follicular helper T but not Th17 cells.J Immunol196(4):1550-7, 2016. doi: 10.4049/jimmunol.1501904 2.Wegner N, Wait R, Sroka A, et al: Peptidylarginine deiminase fromPorphyromonas gingivaliscitrullinates human fibrinogen and α-enolase: implications for autoimmunity in rheumatoid arthritis.Arthritis Rheum62(9):2662-72, 2010. doi: 10.1002/art.27552 