Fecal Calprotectin for the Diagnosis and Management of Inflammatory Bowel Diseases.

Calprotectin is a heterodimeric calcium- and zinc-binding protein mainly derived from the cytoplasm of neutrophils that has direct antimicrobial functions and a role in the regulation of the innate immune response. It can be found in various biological compartments, in particular, the stool, with concentrations related to the level of mucosal inflammation. The measurement of fecal calprotectin has thus been recognized as a useful surrogate marker to distinguish patients with inflammatory bowel disease from those with irritable bowel syndrome. Moreover, it allows the monitoring of intestinal inflammation with a high negative predictive value, making it possible to exclude the diagnosis of inflammatory bowel disease for symptomatic patients. It also shows high sensitivity for the identification of patients requiring additional examinations for diagnosis, such as colonoscopy, and the evaluation of therapeutic responses, providing evidence of relapse or mucosal healing, which can lead to the intensification or reduction of treatment. As calprotectin levels are a measure of mucosal inflammation, high fecal concentrations are also found in other diseases with an inflammatory component, such as infectious enteritis or colorectal cancer. Interpretation of the concentration must therefore always take into account the clinical history and symptoms specific to each patient.

Fecal beta-defensin-2 in children with inflammatory bowel diseases.

Defensins, endogenous antibiotic peptides, are part of the intestinal epithelial barrier. In this pilot study we analyzed the possibility of measuring fecal beta-defensin-2 (HBD2) in comparing inflammatory and noninflammatory conditions. In samples from healthy control individuals, low levels of HBD2 were detectable, which markedly rose under inflammatory conditions (P = 0.0002 vs normal control individuals), the highest levels being observed in patients with ulcerative colitis (median 356 ng/g, range 40-527). Despite frank inflammation, Crohn disease patients with colitis had significantly lower, albeit enhanced, HBD2 levels than did ulcerative colitis patients. These data confirm the possibility of quantifying HBD2 in feces and indicate that colitis in Crohn disease and colitis in ulcerative colitis differ from each other with respect to their ability to secrete HBD2.