Potential biomarkers for lupus disease activity include anti-C1q antibodies, CBCAPs (RC4d, EC4d and EC3d), IFN-a and IFN-inducible genes, B-cell-activating factor (BAFF) or B-lymphocyte stimulator (BlyS), a proliferation inducing ligand (APRIL) [71]. The gene discussed is TNFSF13B; the disease is systemic lupus erythematosus.