EXPRESSION OF CYCLOOXYGENASE‐2 IN COLONIC MUCOSA IN PATIENTS WITH TUBERCULOUS COLITIS

Abstract

Cyclooxygenase‐2 has shown increased expression on crypt epithelium, inflammatory cells of the lamina propria and myenteric neural cells of active inflammatory bowel disease. In tuberculosis colitis, colonoscopic findings are multiple discrete ulcers on terminal ileum, ic valve and cecum with normal surrounding mucosa which are similar with Crohn's colitis. Pathologically the two disease show similar chronic inflammation and granuloma because typical acid fast bacilli and caseation necrosis are not usually detected by biopsy. We evaluated Cox‐2 expression on mucosal biopsy and surgical specimen of tuberculous colitis comparing with Crohn's colitis and nonspecific infectious colitis using immunohistochemistry. This study included 10 patients with tuberculous colitis which are confirmed by antituberculosis treatment, and 10 patients with active Crohn's colitis and 10 patients with acute infectious colitis. We find high Cox‐2 expression on both crypt epithelium and laminar propria lymphocyte (LPL) in all of tuberculous colitis (10 of 10). There are low and weak expression on epithelium (two of 10) and LPL (nine of 10) of Crohn's colitis and epithelium (one of 10) and LPL (seven of 10) of infectious colitis. Cox‐2 expression on crypt epithelium in patients with tuberculous colitis is significantly higher than Crohn's colits and infectious colitis (P < 0.01). This finding suggests that Cox‐2 expression may help differentiate tuberculous colitis from Crohn's colits before experimental antituberculosis medication.