TNF and systemic lupus erythematosus: Studies showed that RIPK1 and RIPK3 could regulate death ligands (such as TNF, FASL) and then activate Caspase 8 to induce apoptosis of immune cells and relieve inflammatory response (10, 11); Whereas Zhu et al. (12) reported that RIPK1 expression in PBMCs from patients with systemic lupus erythematosus (SLE) was negatively correlated with the disease activity index, which suggested that RIPK1 was involved in the immunopathogenic injury in SLE.