The involvement of BAFF in the pathogenesis of autoimmune diseases is well illustrated by BAFF overexpression in mice models, which leads to autoimmune disease mimicking rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and pSS, as well as a twofold increase in occurrence of B cell lymphoma [13]. Here, TNFSF13B is linked to systemic lupus erythematosus.