Fecal Neopterin Versus Fecal Calprotectin for Assessment of Disease Activity in Patients with Inflammatory Bowel Disease

Citation: M Ibrahim. , et al. “Fecal Neopterin Versus Fecal Calprotectin for Assessment of Disease Activity in Patients with Inflammatory Bowel Disease”. EC Gastroenterology and Digestive System 6.9 (2019): 772-782. Introduction: Diagnosis of inflammatory bowel disease (IBD) is a complicated issue combining patient’s history, examination together with laboratory, endoscopic, histologic, and radiographic findings. Ileo-colonoscopy is the preferred method for diagnosis, assessment of disease extent, activity and follow up after therapy but repeated endoscopy is neither practical nor feasible, being invasive, time consuming, and not well tolerated. Therefore, employment of non-invasive biomarkers is needed. Unfortunately, no single marker is ideal. Many studies focus on fecal calprotectin (FC) in IBD and confirm its value in diagnosis, disease activity evaluation, and relapse monitoring. Neopterin, is a metabolite of cyclic guanosine monophosphate that is released by activated T lymphocytes and macrophages after induction by interferon γ. Neopterin release from activated macrophages may provide, at least theoretically by its intrinsic mechanism of release, an advantage over calprotectin which is not secreted and represents a neutrophil-derived protein. Objectives: To investigate the relation between fecal neopterin (fNeo) excretion and IBD clinical and endoscopic activity indices and to compare its ability to discriminate active versus inactive disease with the routine usage of FC Methods: 60 patients were included: 30 patients with ulcerative colitis (UC) (15 clinically in remission, 15 active) and 30 patients with Crohn’s disease (CD) (15 clinically in remission, 15 active) and 20 healthy control subjects. FC and fNeo were detected in stool samples by enzyme-linked immunosorbent assay (ELISA). The following indices were calculated at enrollment: for Crohn’s disease the Crohn’s disease activity index (CDAI) and simple endoscopic score for Crohn’s disease (SESCD); for ulcerative colitis, Simple Clinical Colitis Activity Index (SCCAI) and ulcerative colitis endoscopic index of severity (UCEIS). Results: Among UC patients, fNeo was higher in those with either clinically active or inactive disease than in control subjects (P = 0.001, P = 0.040; for active and inactive disease vs. controls respectively) but there was no significant difference between both UC groups (P = 0.225). For CD patients, fNeo concentration was higher in those with active disease than in those with inactive disease (P < 0.001) or healthy controls (P = 0.001). Non-significant trends toward greater fecal neopterin concentration were observed with increased colonic disease involvement). fNeo was significantly correlated with CDAI (r = 0.604, P < 0.001), SES-CD (r = 0.600, P < 0.001) in CD patients but not with SCCAI, UCEIS in UC patients. fNeo was found to have comparable sensitivity and overall accuracy to FC in predicting endoscopic disease activity in CD patients but less in UC and combing both stool tests together increases the sensitivity and specificity of either alone. Conclusion: Stool neopterin could be used to assess disease activity in CD but not in UC patients as it correlates positively with disease activity indices in CD but not in UC. Thus, its measurement represents a novel reliable biomarker useful to detect and monitor the severity of mucosal affection in CD than UC.