By stimulation with rhBAFF, the MFI of BAFF-R was decreased in B cells from healthy volunteers, consistent with the results of Sellam et al., in which the decreased BAFF-R level was positively correlated with serum BAFF levels and associated with disease activity in pSS and SLE patients. The gene discussed is TNFSF13B; the disease is systemic lupus erythematosus.