CHI3L1 and inflammatory bowel disease: For inflammatory bowel disease (IBD), fecal CHI3L1 has been reported as a novel biomarker of disease activity in pediatric patients184 and endoscopic activity in adult patients.185 For colitis CHI3L1 exacerbates intestinal inflammation by binding to bacterial chitin-binding protein,186,187 enhancing bacterial adhesion and invasion,60 activating Akt signaling145 and IL-6-mediated STAT3 phosphorylation.188