Correlations of Plasma Citrulline Levels With Clinical and Endoscopic Score and Blood Markers According to Small Bowel Involvement in Pediatric Crohn Disease

Objective:Several studies have indicated that plasma citrulline levels reflect the extent of mucosal injury of the small intestine. This study was performed to determine whether plasma citrulline levels correlate with the disease activity in pediatric patients with Crohn disease (CD).Methods:A total of 63 CD and 23 ulcerative colitis (UC) patients were included in this study. Disease severity was assessed by pediatric CD activity index (PCDAI), pediatric UC activity index, simplified endoscopic activity score for CD, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR). The correlations among these variables and plasma citrulline levels were evaluated. We performed subgroup analysis whether correlations between plasma citrulline levels and disease activity depend on small bowel involvement in patients with CD.Results:The plasma citrulline levels correlated negatively with CRP (r=-0.332, P=0.008), ESR (r=-0.290, P=0.022), and PCDAI (r=-0.424, P=0.001) in patients with CD. The plasma citrulline levels were significantly lower in patients with jejunal involvement than in those without (P=0.027). In subgroup analysis, patients with CD with jejunal involvement showed significantly negative correlations of plasma citrulline levels with CRP (r=-0.628, P=0.016) and PCDAI (r=-0.632, P=0.015); however, patients with CD without jejunal involvement revealed no correlations of plasma citrulline levels with CRP and PCDAI. There were no significant correlations between plasma citrulline levels and simplified endoscopic activity score for CD. There were no significant correlations of plasma citrulline levels with CRP, ESR, and pediatric UC activity index in patients with UC.Conclusions:Plasma citrulline levels correlated with disease severity as measured by PCDAI, CRP, and ESR in pediatric patients with CD with jejunal involvement.