TNFSF13B and systemic lupus erythematosus: Belimumab, a recombinant human IgG1 monoclonal antibody that suppresses B-cell-activating factor, was approved for use in patients with active autoantibody-positive SLE and was recently shown to increase the response rate in patients by up to 10% when compared with that for the control (30% vs. 20%, p = 0.02) [25].