TNFSF13B and systemic lupus erythematosus: Currently, the only targeted therapy approved for the treatment of SLE is belimumab, a human monoclonal antibody with specificity for B-cell activating factor (BAFF); this therapeutic is not approved for severe manifestations such as lupus nephritis (LN), which occurs in 40–80% of patients with SLE [6], and has a poor overall response rate [7].