Assessment of Fecal Glycosylated Mucins as Novel Biomarkers in Inflammatory Bowel Diseases

To the Editors: With great interest we read the article by Robbe Masselot et al,1 who reported on human fecal mucin glycosylation in patients with inflammatory bowel disease (IBD) and non-IBD individuals. Using stool samples from 48 patients with Crohn’s disease (CD), 12 individuals with unrelated IBD, and 5 healthy control (HC) subjects, glycosylation profiles of fecal mucins (O-glycans) were analyzed. Expression levels of 4 specific O-glycans were compared between patients with active CD, patients with inactive CD, patients with unrelated IBD, and HC subjects. The authors concluded that their novel approach of mucin analysis could be a reliable tool to distinguish CD patients from unrelated IBD patients, and that it may even be relevant beyond the scope of IBD. Based on these compelling data and the formulated aim of determining the ability of O-glycans to discriminate between CD and unrelated IBD (ie, patients with irritable bowel syndrome or HC subjects), we reasoned that extended data analysis may be worth pursuing. For example, receiver-operating characteristic analysis could be useful to assess the ability of O-glycans to discriminate between IBD and non-IBD, evaluating both sensitivity and specificity across different classification thresholds.2 This approach helps to assess overall discriminative performance and may be utilized to find potentially optimal cutoffs, preferably followed by cross-validation to generate more realistic estimates. Although we acknowledge that this does not directly guarantee clinical relevance, it would provide additional information and is easily interpretable.