Fecal calprotectin: a quantitative marker of colonic inflammation in children with inflammatory bowel disease.

Objectives: The protein calprotectin (S100 A8/A9) is present in neutrophils, monocytes, and macrophages. Colorectal inflammation can be detected by increased excretion of fecal calprotectin (FC). The aim of this study was to evaluate FC as a quantitative marker of inflammatory activity in children with inflammatory bowel disease (IBD).
Patients and Methods: Thirty-nine children with IBD delivered a fecal spot sample and underwent colonoscopy. The samples were examined with an enzyme-linked immunosorbent assay for FC (Calprest, Eurospital, Trieste, Italy). The concentrations were correlated to macroscopic and microscopic assessments of extent and severity of inflammation in 8 colonic segments for each patient.
Results: FC correlated significantly to the macroscopic extent (Spearman rho = 0.61) and the severity (Spearman rho = 0.52) of colonic inflammation and to a macroscopic, combined extent and severity score (Spearman rho = 0.65). Significant correlations also were found to the microscopic extent (Spearman rho = 0.71) and severity (Spearman rho = 0.72) of colonic inflammation and to a microscopic, combined extent and severity score (Spearman rho = 0.75). The median FC was 392 mug/g (95% confidence interval [CI], 278-440) in children with clinical IBD symptoms (n = 23) and 32.9 mug/g (95% CI, 9.4-237) in asymptomatic IBD patients (n = 16). Of the asymptomatic children, 56% had a complete microscopic mucosal healing, and their median FC was 9.9 mug/g (95% CI, 5.9-41.9).
Conclusions: FC can be used as a surrogate marker for estimation of colonic inflammation in pediatric IBD. Normalized FC concentration seems to indicate complete mucosal healing. FC is simple to obtain and analyze; this should facilitate objective assessment and monitoring of IBD activity.