Paradoxical effects of tumour necrosis factor-α in adjuvant-induced arthritis

Anti-tumour necrosis factor (TNF)alpha therapy is highly effective in rheumatoid arthritis and it is surprising, therefore, that a recent study showed that intraperitoneal administration of recombinant TNFalpha reduced the severity of adjuvant-induced arthritis and decreased IFNgamma expression in cultured draining lymph node cells. Furthermore, in untreated arthritic rats, maximal TNFalpha expression in draining lymph node cells coincided with spontaneous disease remission, suggesting a role for endogenous TNFalpha in recovery from arthritis. If confirmed in further studies, these findings suggest that, in addition to its well-established pro-inflammatory properties, TNFalpha may also play a disease-limiting role in this model of rheumatoid arthritis by suppressing effector T cell responses.