Background: Cytokines are involved in the pathogenesis of inflammatory bowel diseases such as ulcerative colitis and Crohn disease.

Objective: To measure cytokine release by mononuclear cells of patients with ulcerative colitis.

Methods: Twelve patients subjected to a diagnostic colonoscopy were studied. Six had an ulcerative colitis and six did not have inflammatory changes in the colonic mucosa and were considered as control. Mononuclear cells were isolated from biopsies of colonic mucosa and from peripheral blood cultivated during 48 hours with pokeweed mitogen, and Interleukin 6 and interferon-gamma were measured in their supernatants.

Results: In patients with ulcerative colitis, interleukin 6 secretion by peripheral blood mononuclear cells was higher than in control subjects in the basal period (2212 +/- 424 and 443 +/- 174 pg/ml respectively p = 0.03) and after stimulation with pokeweed mitogen (16,328 +/- 1275 and 5462 +/- 322 pg/ml respectively p = 0.03). No differences in interleukin 6 secretion by colonic mucosa mononuclear cells were observed. Unstimulated cells did not liberate interferon-gamma. The secretion of this lymphokine by stimulated colonic mucosa cells was lower in patients with ulcerative colitis than in controls (1571 +/- 216 and 7953 +/- 389 pg/ml respectively p = 0.03).

Conclusions: Local and systemic changes in interleukin 6 and interferon-gamma secretion occur in patients with ulcerative colitis. These changes could be related to the development of the disease.