TAGAP and rheumatoid arthritis: The three autoimmune diseases examined in the current study are characterised by the presence of autoantibodies and, interestingly, the association of the TAGAP variant is stronger in the subgroup of RA patients with anti-cyclic citrullinated peptide (anti-CCP) antibodies (P-trend = 0.0001, allelic OR 0.83 95% CI 0.75 to 0.91), suggesting a possible role in control of B cell function.