Fecal calprotectin, MMP-9, and human beta-defensin-2 levels in pediatric inflammatory bowel disease

Fecal MMP-9 and human beta-defensin-2 (HBD-2) levels, potential markers of intestinal inflammation, are insufficiently explored in pediatric inflammatory bowel disease (IBD). The aim was to study fecal MMP-9 and HBD-2 in pediatric IBD to compare their performance to calprotectin and to study whether they would provide additional value in categorizing patients according to their disease subtype. Fecal calprotectin, MMP-9, and HBD-2 levels were measured with ELISA in 110 pediatric patients with IBD (Crohn's disease, n = 68; ulcerative colitis (UC), n = 27; unclassified, n = 15; median age, 14). To compare the performance of the fecal markers, the area under the receiver operating characteristics curve (+/- 95 % CI) was used. In addition, the best cut-off values of each measure to differentiate IBD patients and controls (n = 27 presenting with diarrhea, abdominal pain, and/or anemia) were derived by maximizing sensitivity and specificity. Of the fecal markers studied, calprotectin performed best for separation of IBD and non-IBD patients with the area under curve (AUC) of 0.944 (95 % CI, 0.907 to 0.981). For MMP-9, AUC was 0.837 (95 % CI, 0.766 to 0.909), the levels being significantly higher in active IBD and in UC compared with Crohn's disease (p = 0.0013), but categorization of these patient groups did not take place. HBD-2 did not categorize any of the studied groups. Calprotectin was the best fecal marker in pediatric IBD, but MMP-9 showed almost comparable performance in UC, suggesting applicability as a surrogate marker of inflammation. Fecal HBD-2 did not bring information to the disease characteristics of pediatric IBD patients.