Rheumatoid arthritis (RA)
Rheumatoid factor (antibodies against IgG) and anti-CCP (surrogate for anti-citrullinated protein antibodies or ACPAs) have long-defined seropositive rheumatoid arthritis. New findings urge rheumatologists to re-evaluate these gold standard RA autoantibodies. How important is citrulline? Emerging evidence suggests that citrullinated proteins are one of several post-translational modifications targeted by cross-reactive autoantibodies in RA. This session reviews new anti-modified protein antibodies (AMPAs) and considers: Is citrullination a special modification targeted by RA autoantibodies or simply the first to be characterized? Findings have importance for how we assess RA autoantibody repertoires and future diagnostics. Although RF and anti-CCP often co-exist, new evidence suggests unique risk factors for each, different timing in pre-clinical RA, different pathophysiologic roles, and both common and unique epitopes. This session highlights recent findings, discusses the role of RF in health and disease, and considers how new knowledge could reshape diagnostics.