TNF and rheumatoid arthritis: Although TNF plays a major role in growth regulation, cell differentiation, and response to microbial infections, its inappropriate overexpression has been implicated in the pathogenesis of a wide spectrum of human disorders, such as autoimmunity (e.g., multiple sclerosis, rheumatoid arthritis, inflammatory bowel disease), allergy, septic shock, allograft rejection, and insulin resistance.