Local and systemic liberation of proinflammatory cytokines in ulcerative colitis

Determination of plasma and tissue cytokine levels in inflammatory bowel di sease have frequently resulted in conflicting data. In the present study we determined in patients with ulcerative colitis (UC), the levels of the pro inflammatory cytokines interleukin (IL)-1 beta, IL-6, interferon (IFN)-gamm a, and tumor-necrosis factor (TNF)-alpha liberated by peripheral blood mono nuclear cells (PBMC) and lamina propria mononuclear sells (LPMC) after 48-h r culture with pokeweed mitogen (PWM). IL-1 beta, IL-6, IFN-gamma and TNF-a lpha in the supernatant were detected by ELISA. Results show low basal leve ls of IL-1 beta secretion by PBMC and LPMC, and a considerable increase aft er mitogen stimulation. Basal IL-6 production by PBMC was higher in UC pati ents-than in controls [2029 pg/ml. CI95(-165 to 4223) vs 572 pg/ml (-383 to 1527) respectively, P = 0.05] and also after PWM activation [14,995 pg/ml (7759-22230) vs 6598 pg/ml (3240-9956), rsspectively, P = 0.05], In LPMC, n o differences in IL-6 secretion were observed. TNF-alpha in activated PBMC of patients with UC was not significantly increased in relation to control (P = 0.09). No constitutive secretion of IFN-gamma was observed in mononucl ear cells. IFN-gamma levels secreted by activated LPMC were lower in patien ts with UC than in controls [1571 pg/ml (-108 to 3251) vs 7953 pg/ml (3551- 12.055), respectively, P = 0.03]. These results suggest that IL-6, IL-1 bet a, and TNF-alpha participate as mediators in the inflammatory phenomena obs erved in UC. Further studies are necessary to evaluate the role of IFN-gamm a in this condition.