Although the bone marrow provides the survival niche for long-lived plasma cells [5, 6], inflammatory tissues bear high B cell-activating factor (BAFF) and a proliferation-inducing ligand (APRIL), maintain long-lived plasma cell survival, and thus contribute to the autoantibody secretion in inflammatory joints in patients with RA [7] and nephritic kidneys in NZB/W mice [8]. Here, TNFSF13 is linked to rheumatoid arthritis.