The efficacy of belimumab, a human monoclonal antibody targeting soluble BAFF, approved for the treatment of SLE, in a phase II clinical trial of primary SS strongly supported the pathogenic role of BAFF in this autoimmune disease (75, 76), and a phase III trials of belimumab in co-administration with rituximab in primary SS is ongoing (NCT02631538). Here, TNFSF13B is linked to systemic lupus erythematosus.