Chronic use of non-steroidal anti-inflammatory drugs does not alter colonic mucosa of patients without diarrhoea

Background: Several types of colitis can be NSAID-induced, but whether chro nic use of NSAIDs alters colonic mucosa in patients without diarrhoea is no t known. Patients and methods: Biopsy specimens of rectal mucosa. were taken in six patients with rheumatoid arthritis without diarrhoea receiving NSAIDs (grou p 1, n = 6). Patients with rheumatoid arthritis without diarrhoea not recei ving NSAIDs (group 2, n = 9), and patients undergoing surveillance colonosc opy (group 3, n = 23) served as controls. In all patients from the three st udy groups, intraepithelial lymphocyte count and apoptotic cell count were assessed, and sub-epithelial collagen band thickness was measured. Leucocyt e population of lamina propria was evaluated semi-quantitatively. HLA-DR an d CD25 expression of mucosal cells was appreciated by immunohistochemistry. Results: Intraepithelial lymphocyte count was in the normal range in all th ree group patients, and not statistically different between groups. Apoptot ic epithelial cell count was not different between groups. Subepithelial co llagen band thickness was normal in all the patients. No patient had a mark ed infiltration of lamina propria by leucocytes, and HLA-DR and CD25 were n ormally expressed in all patients. Conclusion: These results from a small sample of patients suggest that pati ents without diarrhoea receiving NSAIDs on a long-term basis do not develop microscopic or inflammatory colitis.