Belimumab (trade name Benlysta) is a human monoclonal antibody that inhibits the cytokine B cell activating factor known as BAFF or BLYS and is to some extent responsible for the the increased autoantibody production observed in patients with systemic lupus erythematosus (SLE).(Zhang et al.2001; Petri et al.2008). This evidence concerns the gene TNFSF13B and systemic lupus erythematosus.