Inflammatory bowel disease mucosal biopsies have specialized lymphokine mRNA profiles

Crohn's disease (CD) and ulcerative colitis (UC) are idiopathic inflammatory bowel diseases (IBD) that are characterized by chronic intestinal inflammation and are associated with abnormalities of peripheral and mucosal immune function. The aim of our study was to determine whether CD or UC is characterized by discrete profiles of intestinal lymphokine production. Total cellular RNA was isolated from biopsies of healthy controls and from patients with IBD. Messenger RNA transcript levels in biopsies were determined for interleukin-2 (IL-2), IL-4, IL-5, and interferon-gamma (IFN-gamma), using a quantitative reverse transcriptase polymerase chain reaction method. Compared with inflamed UC mucosa and controls, CD mucosal lesions contained higher IL-2 and IFN-gamma mRNA (p < 0.05), which is consistent with a T-helper cell 1 (Th1)-like pattern. In UC, IL-5 mRNA content was higher in involved areas compared with controls (p < 0.05) and inflamed CD lesions (p < 0.05), suggestive of a Th2 pattern. We conclude that the intestinal mucosa of CD and UC have inflammatory responses characterized by discrete T-helper profiles of lymphokines. This strongly suggests that the immunopathogenesis of these two forms of IBD are different.