Fecal Calprotectin Mirrors Inflammation of the Distal Ileum and Bowel Function After Restorative Proctocolectomy for Pediatric-Onset Ulcerative Colitis

Background: The goal was to cross-sectionally assess fecal calprotectin after restorative proctocolectomy for pediatric-onset ulcerative colitis (UC). Methods: Fecal calprotectin, histology of the distal ileum, inflammation biochemistry, episodes of pouchitis, and bowel function were cross-sectionally determined at early adulthood in 32 patients who had undergone proctocolectomy with ileoanal anastomosis for UC at a mean (SD) age of 12.0 +/- 4.1 years. Results: A total of 15 (47%) patients showed increased (>100 mu g/g) fecal calprotectin (669 +/- 866 mu g/g), although their serum C-reactive protein (5.2 +/- 3.8 mg/L), erythrocyte sedimentation rate (13 +/- 13 mm/h), and white blood cell count (6.7 +/- 1.7 E9/L) were normal or slightly elevated. Calprotectin correlated positively with the histological neutrophil count of the distal ileum (r = 0.715; P < 0.001), the frequency of pouchitis (r = 0.468; P < 0.01), and with the maximum daily frequency of bowel actions (r = 0.610; P < 0.001). Mean fecal calprotectin was 71 +/- 50 mu g/g among patients with no history of pouchitis (n = 10), 290 +/- 131 mu g/g among patients with a single episode of pouchitis (n = 15), and 832 +/- 422 mu g/g among those with recurrent pouchitis (P = 0.019 between recurrent pouchitis and no pouchitis). Sensitivity, specificity, positive predictive value, and negative predictive value for fecal calprotectin concentration over 300 mu g/g to detect recurrent pouchitis were 57%, 92%, 67%, and 89%, respectively. Conclusions: Neutrophilic inflammation of the distal ileum, as reflected by fecal calprotectin, is common after restorative proctocolectomy for pediatric-onset UC.