Disappointingly, the vast majority of tested therapies failed their primary endpoints,11 except belimumab, an inhibitor of the cytokine BAFF, showing modest efficacy in a subset of patients with SLE.12 Highly variable responses to treatments could be explained by the fact that recruitment of patients into clinical trials is based on a limited set of clinical manifestations and/or clinical scores, unlikely to fully capture the differences between patients. This evidence concerns the gene TNFSF13B and systemic lupus erythematosus.