A patient’s antibody profile is a measure of the reactivity of their immune system and a historical record of the diseases they’ve had in the past. As such, the antibodies a patient has can be predictive of how that patient will react to both disease and immunotherapy. Autoantibodies are causative elements of autoimmune diseases, but these antibodies are not solely related to autoimmune diseases. COVID-19 has highlighted that viral infection can cause immune systems to overreact, releasing autoantibodies, which can in part be responsible for some of the symptoms of PASC (Long COVID). This session will explore the contribution of autoantibodies to disease and treatment and their utility as a novel biomarker class that can augment existing biomarkers, supporting the goal of better patient stratification and precision medicine.