A clinical trial showed that in SLE patients treated with belimumab, an inhibitor of B-lymphocyte stimulator (BLyS) which exceptionally attenuate the risk of lupus nephritis flare and eGFR decline, the loss of cells consistent with the age-associated B Cell (ABC) phenotype was correlated with therapeutic response. The gene discussed is TNFSF13B; the disease is systemic lupus erythematosus.