Rheumatoid Arthritis
An autoimmune synovitis in which loss of tolerance to self-antigens drives a chronic inflammatory pannus that erodes cartilage and bone, symmetrically, from the small joints inward.
First principles
Rheumatoid arthritis begins with a loss of immune tolerance, not mechanical wear
In genetically susceptible individuals (particularly those carrying HLA-DR4/shared epitope alleles), environmental triggers such as smoking drive citrullination of self-proteins, which the immune system then fails to recognise as self. T-cell-driven B-cell activation produces autoantibodies, rheumatoid factor and, more specifically, anti-citrullinated protein antibodies (anti-CCP), often years before joint symptoms appear. Because the trigger is a systemic autoimmune process rather than local mechanical stress, rheumatoid arthritis is symmetrical and can also affect organs beyond the joint.
Educational content pending clinical review. Not medical advice.