Blisibimod inhibits the interaction of BAFF with any of its three receptors (half-maximal inhibitory concentration [IC50] = 0.2 nM at 1 nM BAFF), inhibits the in vitro BAFF-driven increases in B cell proliferation (IC50 = 0.1 nM at 0.2 nM BAFF), reduces in vivo peripheral B cell numbers in non-autoimmune-prone mice, and delays the onset of proteinuria in SLE-prone (NZBxNZW)F1 mice [24]. This evidence concerns the gene TNFSF13B and systemic lupus erythematosus.