TNF and polyarticular arthritis: Here, total active corticosterone and inactive 11-DHC, increased in TNF-tg and TNF‐tg11βKO mice, with the reduced transcortin binding affinity of 11-DC predicted to further elevate its circulating free levels.25 In the models of polyarthritis, disease activity, synovitis and joint destruction were markedly suppressed in animals receiving corticosterone.