Clinical role of calprotectin assay in determining histological relapses in children affected by inflammatory bowel diseases

BACKGROUND: Inflammatory bowel diseases (IBD) are characterized by periods of remission with recurrent episodes of symptom exacerbation because of acute intestinal inflammation, which is correctly evaluated by endoscopy with biopsy sampling. However, many surrogate markers of intestinal inflammation, including fecal calprotectin (FC), are detected as potential predictors of mucosal inflammation in IBD patients. The aim of our study was to retrospectively assess the clinical efficacy of the calprotectin assay in determining histological relapses of pediatric IBD patients. METHODS: We retrospectively reviewed the histological examinations, clinical records, and FC values of patients who had undergone colonoscopy at our hospital over an 8-year period, from December 31, 1998, to December 31, 2006. Only patients with a first histological examination showing a quiescent IBD who submitted to a second histological examination during the next 3 years were selected. RESULTS: Seventy-three IBD patients, all with a first biopsy showing a quiescent IBD, were studied; at the second histological examination, 32 presented with relapse and 41 presented with remission. Relapsed patients showed significantly increased FC levels compared with nonrelapsed patients. A FC value of 275 mug/g achieved sensitivity and negative predictive value of 97% and specificity and positive predictive value of 85% in predicting histological relapse. CONCLUSIONS: FC seems to be a direct measure of intestinal inflammation and therefore a good marker of the risk of histological relapse in pediatric IBD patients. The application of this test in clinical practice may enable the avoidance of invasive tests as well as targeting treatment.