Circulating antiinflammatory cytokine IL-10 in patients with inflammatory bowel disease (IBD)

Abstract

SUMMARY IBD is characterized by increased serum concentrations of different cytokines. IL-10 inhibits the production of proinflammatory cytokines such as IL-1, tumour necrosis factor-alpha (TNF-a), interferon-gamma (IFN-γ) and IL-6 through inhibitory action on Th1 cells and macrophages, and it is thought to be a suppressor type cytokine. In the present study we determined serum concentrations of IL-10 in patients with ulcerative colitis (UC) and Crohn's disease (CD). We measured human IL-10 by our own newly established ELISA system using PharMingen antibodies. Serum antibodies were assessed in 44 patients with UC, 40 patients with CD, and in 30 healthy controls. Human IL-10 serum levels were significantly increased in patients with active UC (144 ± 34 pg/ml (mean ± s.e.m.), P <0.001) and in active CD (132 ± 32 pg/ml, P <0.001) compared with healthy controls (44.9.5pg/ml). Only patients with active CD and active UC presented with significantly increased IL-10 serum levels, while patients with inactive disease did not show any significant increase. There was no statistically significant difference between IL-10 serum levels in patients with CD or UC. Compared with clinical disease activity indices there was a significant correlation between IL-10 serum concentration and CDAI in patients with CD (r= 0.45, P <0.01) and CAI in VC patients (r= 0.39, P <0.05). Comparing IL-10 serum levels with serum concentrations of other proinflammatory cytokines there was a significant correlation to scrum levels of sIL-2R (r= 0.417, P <0.05) and IL-6 (r= 0.387, P <0.05) in patients with CD. Serum cytokine levels in patients with UC did not show any significant correlation to IL-10 serum concentration. IL-10 is elevated in serum of patients with active CD and UC. suggesting that IL-10 acts as a naturally occurring damper in the acute inflammatory process of IBD.