Is pyloric gland metaplasia in ileal pouch biopsies a marker for Crohn's disease?

backgroundApproximately 5-10 % of ulcerative colitis (UC) patients who undergo ileal pouch-anal anastomosis (IPAA) will develop postoperative complications such as refractory pouchitis or a change in diagnosis to Crohn's disease (CD). Serological markers and histologic aspects of the pouch such as pyloric gland metaplasia (PGM) have been associated with a risk for these complications.

methodsTwenty-eight IPAA patients with either CD of the pouch or chronic pouchitis (cases) and 36 IPAA controls who experienced a normal postoperative course were originally consented. Of these 64 subjects, 22 cases and 17 controls had histopathologic and serologic data available and were subsequently enrolled. Demographic and clinical data were entered into a database, blood analyzed for serological markers (Prometheus Labs, San Diego, CA) and biopsies of the pouch and the afferent limb reviewed by two GI pathologists.

resultsOf the cases, 55 % (12/22) had evidence of PGM in their pouch and/or small bowel biopsies, as compared to 12 % (2/17) of the controls (p = 0.006). Of 13 subjects with CD, 77 % (10/13) were found to have PGM versus subjects with chronic pouchitis in which 22 % (2/9) were found to have PGM (p = 0.03). There was a trend of ASCA positivity (both IgG and IgA, p = 0.20) and of higher ASCA titer levels (p = 0.07) with postoperative complications.

conclusionThis study suggests that the presence of ileal pouch PGM is associated with postoperative complications and favors a diagnosis of CD over UC with chronic pouchitis.