Increased concentrations of BAFF and the association between increased BAFF concentrations and worsening disease after rituximab therapy,4 led us to design a placebo-controlled clinical trial (BEAT-LUPUS) comparing treatment with belimumab after rituximab to rituximab alone for patients with SLE whose disease was refractory to conventional therapy. This evidence concerns the gene TNFSF13B and systemic lupus erythematosus.