Mucosal inflammation in the terminal ileum of ulcerative colitis patients: endoscopic findings and cytokine profiles.

Background: Currently, published reports of mucosal inflammation in the terminal ileum of ulcerative colitis (UC) before colectomy are scarce.

Aim: To investigate inflammation in the terminal ileum of UC patients by endoscopic examinations and measurement of mucosal cytokine profiles.

Methods: Fifty consecutive patients with active UC were studied. At ileocolonoscopy, mucosal biopsies were taken from the terminal ileum. As control, mucosal biopsies from 20 patients without inflammation were examined.

Results: Thirty-eight patients showed endoscopically normal terminal ileum, four showed backwash ileitis, and eight showed non-backwash ileitis (ileitis with normal caecum). Pancolitis was observed in all of four patients with backwash ileitis, in 4 of 8 (50%) with non-backwash ileitis, and in 4 of 38 (11%) without ileal inflammation (P=0.0002). Extraintestinal manifestations were observed in none of 4 patients with backwash ileitis, in 6 of 8 (75%) with non-backwash ileitis, and in 3 of 38 (8%) without ileal inflammation (P<0.0001). In patients with backwash ileitis and non-backwash ileitis, ileal interleukin [IL]-1beta, IL-6, IL-8 and tumour necrosis factor-alpha levels were significantly elevated compared with the control group. Only extraintestinal manifestation was associated with higher ileal cytokine levels, whereas age, sex, and duration, extent and severity of UC did not show any apparent association.

Conclusions: In patients with backwash ileitis, elevated ileal cytokines might reflect a reaction to regurgitation of colonic content into the ileum, but in patients without backwash ileitis, alternative factors are expected to contribute to the aetiology of ileal inflammation. Patients with extraintestinal manifestations had elevated ileal cytokine levels.