M1 macrophages mediate inflammatory responses to a variety of bacterial, protozoal, and viral infections, and produce many inflammatory cytokines, including TNFα, IL-12, IL-18, and IL-23, in several chronic inflammatory and autoimmune diseases, including RA, Crohn’s disease, multiple sclerosis, and autoimmune hepatitis [138,139]. The gene discussed is TNF; the disease is rheumatoid arthritis.