Serum BAFF levels were elevated in our SLE cohort (mean=0.61±0.13 ng ml−1 in healthy controls; mean=2.11±4.32 ng ml−1 in SLE patients, P=0.0004, Wilcoxon–Mann–Whithney test), and correlated with sBCMA levels (P=0.0013, r=0.47, Spearman rank correlation). This evidence concerns the gene TNFSF13B and systemic lupus erythematosus.