Inflammatory bowel disease in patients with primary sclerosing cholangitis: Clinical characterization in liver transplanted and nontransplanted patients

Background: Inflammatory bowel disease (IBD) in patients with primary sclerosing cholangitis (PSC) seems to differ from IBD without PSC, but a systematic, prospective study of IBD in PSC has until now not been reported. We aimed to describe the clinical, endoscopic, and histopathologic features of PSC-IBD in liver-transplanted and nontransplanted patients. Methods: PSC patients (n = 184) were included and underwent ileocolonoscopy with assessment of segmental histopathology. Results: A total of 155 (84%) patients had IBD, of whom 39 (25%) had undergone colectomy. The patients with an intact colon and complete tissue samples (n 110) were further investigated. Forty-two (38%) patients had undergone liver transplantation. The median IBD duration was 11 (range, 0-50) years. The majority (65%) had no or sparse IBD symptoms. Inflammatory findings were more frequent by histology than by endoscopy (89% versus 47%, P < 0.001). Histopathological signs of inflammation involved the right colon in 86% of patients and were purely right-sided in 23%. The findings of inflammation were higher in the right compared to the left colon (P < 0.001), but the general inflammatory activity was low. Backwash ileitis was demonstrated in 20% (17/87) of patients and rectal sparing in 65% (70/107). The liver-transplanted patients had lower clinical (P = 0.035) and histological (P = 0.013) IBD activity than the nontransplanted group. Conclusions: PSC-IBD may represent a distinct entity of colitis in which low endoscopic activity may mask an active histologic inflammation that possibly contributes to an increased risk of malignancy. Circumstances related to liver transplantation seem to act favorably on colonic inflammation in PSC.