Purpose
Autoantibody production is a characteristic of most autoimmune diseases including rheumatoid arthritis (RA), but the stage of B-cell development at which B-cell tolerance is broken remains unknown. We previously established in healthy donors that most autoreactive developing B cells were removed either in the bone marrow or in the periphery, revealing two B-cell tolerance checkpoints. We aimed to determine whether the autoreactive B cells in RA evade one or both of these checkpoints. In addition, analysis of the antibody repertoires in RA might lead to potential insights about the mechanisms that may explain loss of B-cell tolerance.