The Roles of Four Neutrophil-Derived Proteins as Non-Invasive Biomarkers in the Assessment of Inflammatory Bowel Disease.

Inflammatory bowel disease (IBD) can present at any age with a range of gastrointestinal (GI) symptoms or extra-intestinal manifestations. Management of IBD focuses on the establishment and maintenance of disease control (remission) in order to reduce the risk of long-term gut damage and complications such as strictures or colitis-associated carcinoma. Non-invasive biomarkers can have roles in initial assessment, differentiation from other GI disorders, quantification of current inflammatory burden, assessment of the success of a specific intervention and the prediction of disease relapse. While the neutrophil-derived protein calprotectin is used widely as a biomarker, this review focuses specifically on data supporting the roles of four additional specific neutrophil-derived proteins: myeloperoxidase, S100A12, lactoferrin and lipocalin. A number of recent studies demonstrate the value of myeloperoxidase, with promising developments for a rapid test. S100A12 provides strong differentiation between IBD and other conditions, with apparent superior performance in children. Lactoferrin provides similar test utility to calprotectin, while lipocalin has great promise for evaluation of both serum or fecal levels. Further studies should focus on additional evaluation of these promising markers.