ILEOSTOMY CALPROTECTIN STAINING AFTER ILEAL POUCH ANAL ANASTOMOSIS CORRELATES WITH APPENDICEAL INFLAMMATION, A KNOWN PREDICTOR OF AN EARLIER ONSET OF POUCHITIS IN ULCERATIVE COLITIS AND INDETERMINATE COLITIS
Adam Petchers*1, Soe Htet Arker1, Georgi Lukose2, Edward C. Lee1, Hwajeong Lee1
1Surgery, Albany Medical Center, Albany, NY; 2New York Presbyterian Hospital-Weill Cornell Medicine, New York, NY
Background Pouchitis is a nonspecific inflammation of the ileal pouch reservoir that may occur after IPAA. The procedure is performed as a multi-stage operation with creation and subsequent resection of diverting ileostomy. We have previously reported that severe appendiceal inflammation on the colectomy specimen is associated with a shorter time interval to development of pouchitis, as is an increase in fecal calprotectin levels, in UC and IC. We aim to assess the predictive value of calprotectin and lactoferrin immunohistochemistry in the ileostomy specimens.
Methods A retrospective chart review was performed for UC/IC patients who underwent IPAA to identify those with clinically significant pouchitis and to assign a Pouchitis Disease Activity Index (PDAI) score, with ?7 consistent with pouchitis. Calprotectin and lactoferrin immunostain was performed on formalin-fixed paraffin-embedded tissue blocks of ileostomy specimens. The staining extent was assessed as a continuous variable over the length of the specimen. When patients had multiple ileostomies, the staining was averaged across the specimens. Archived H&E slides of the preceding colectomy specimens were reviewed and were graded for the extent of colitis, fissuring ulcer, backwash ileitis and appendiceal inflammation (1-6). Demographics, smoking history and subsequent development of Crohn's disease-like condition of the pouch (CDP) were recorded.
Results 87 ileostomy specimens were reviewed from 69 patients (83% UC, 17% IC; mean age 34 (6-76) years; male: female 32:37). The mean follow-up duration after resection of ileostomy was 67 (2-196) months. Clinically significant pouchitis or PDAI ?7 was observed in 64% and 39% of the patients, respectively. There was no difference in the age, gender and smoking history in patients with and without pouchitis (p>0.05). All CDP patients (n=9) had clinical pouchitis and PDAI ?7. The mean extent of ileostomy calprotectin staining in those with clinically significant pouchitis was 37.6% vs. 42.8% without pouchitis, similar to staining for those with PDAI ?7 (41.2%) and <7 (40.7%). Calprotectin staining did not correlate with time to pouchitis in either group. When assessed as a continuous variable, the mean of calprotectin staining correlated with appendiceal inflammation scores on H&E (32.8% vs. 50.4% for 1-3 vs. 4-6, p=0.036), but did not correlate with extent of colitis, fissuring ulcer or backwash ileitis. Lactoferrin staining was negative.
Conclusion While calprotectin staining of the ileostomy specimens did not independently correlate with subsequent rate of or time to development of pouchitis, it correlated with appendiceal inflammation of the colectomy specimen on H&E, which is associated with earlier development of pouchitis. Further investigation into the utility of the ileostomy specimen in prediction of pouchitis is warranted.
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