TNF and rheumatoid arthritis: Following the foregoing, KLF9 is down‐regulated in MH7A cells (human rheumatoid arthritis fibroblasts) induced by TNF‐α, while the enhancement of KLF9 can inhibit the release of pro‐inflammatory factors (IL‐1β, IL‐6, IL‐8, iNOS and COX‐2).123, 124