TNF and rheumatoid arthritis: While CD56bright NK cells are mainly found in the peripheral inflammatory sites of lymph nodes, and can secrete and produce inflammatory cytokines such as IFN-γ, TNF-α, etc. IFN-γ can induce macrophage M1 polarization and Th17 inflammation-promoting cell differentiation (47), which promotes the generation of OC and further exacerbates the osteoarthritic injury response, thus promoting the process of RA.