TNFSF13 and systemic lupus erythematosus: Increased serum levels of “A proliferation-inducing ligand” (APRIL), “B-cell–activating factor” (BAFF), interferon α, interferon γ, interleukin 6 (IL-6), IL-12, IL-17, and tumor necrosis factor alpha are found to be positively correlated with autoreactive antibody production, SLE Disease Activity Index scores, and organ involvement (2).