TNFSF13B and systemic lupus erythematosus: Belimumab, a human immunoglobulin G1λ monoclonal antibody against B lymphocyte stimulator (BLyS) [12], is an example of such a treatment, with IV and SC formulations available for the treatment of patients ages 5 years and older and 18 years and older, respectively, with active, autoantibody-positive SLE who are receiving standard therapy [13–16].