TNFSF12 and systemic lupus erythematosus: TNF-like weak inducer of apoptosis (TWEAK) is a proinflammatory cytokine from the TNF superfamily that binds monogamously to its receptor Fn14.9 TWEAK plays a prominent role in the pathogenesis of LN through several intracellular signal transduction cascades and induces apoptosis of glomerular mesangial cells and tubular epithelial cells.10 In a mouse model of SLE, Fn14 deficiency or treatment with an anti-TWEAK antibody significantly reduced renal inflammation as well as proteinuria.11