Cytokine messenger RNA profiles in inflammatory bowel disease mucosa detected by polymerase chain reaction amplification.

Immunoregulatory properties of cytokines may mediate disordered inflammatory events in ulcerative colitis (UC) and Crohn's disease (CD). In the present study, profiles of cytokines produced by activated macrophages were studied in colonic tissue from 43 patients with and without inflammatory bowel disease (IBD). Cytokine messenger RNA (mRNA) extracted from mucosal biopsy specimens was studied using polymerase chain reaction assay techniques. A greater percentage of active UC samples had detectable levels of mRNA for interleukins (IL) 1, 6, and 8 and gro than samples in inactive UC and noninflammatory controls. These cytokines were comparable in active UC and inflammatory controls. Expression of gro mRNA in active UC tissue was significantly higher than in active CD. Tumor necrosis factor was detected in only 7 of 43 samples with no difference between groups. Active and inactive CD did not differ in percentage of cytokine mRNA expression. IL-1 receptor antagonist (IL-1ra) was detected in more inflammatory controls than in CD and was expressed in fewer IBD patients than IL-1. Expression of proinflammatory cytokines in grossly inactive CD and possible defective production of IL-1ra may explain disease reactivation and chronicity.