Serum oncostatin M is a potential biomarker of disease activity and infliximab response in inflammatory bowel disease measured by chemiluminescence immunoassay.

BACKGROUND Although endoscopy is the gold standard to assess disease activity and infliximab efficacy in inflammatory bowel disease (IBD), the invasive, costly, and time-consuming procedure limits its routine applications. We aimed to investigate the clinical value of serum oncostatin M (OSM) as a surrogate biomarker. METHODS Fifty healthy controls, 34 non-IBD patients, and 189 IBD patients who were pre-infliximab treatment (n = 122) or in infliximab maintenance (n = 67) were enrolled. A chemiluminescence immunoassay (CLIA) was constructed to quantify serum OSM concentrations. Receiver operator characteristic (ROC) curve analysis was used to evaluate the performance of blood biomarkers for IBD management. RESULTS The methodology of CLIA exhibited great analytical performance with a wide linear range of 31.25-25000 pg/mL, a low detection limit of 23.2 pg/mL, acceptable precision, and applicable accuracy. Patients with IBD (121.5 [43.3-249.4] pg/mL, p < 0.001) and non-IBD (72.4 [51.4-129.6] pg/mL, p = 0.005) had higher serum OSM levels than healthy controls (35.8 [23.2-56.4] pg/mL). In the analysis of clinical and endoscopic activity, serum OSM levels were elevated in moderate and severe patients compared to those in remission. IBD patients without mucosal healing had higher serum OSM levels than those with mucosal healing (AUC = 0.843). Besides, serum OSM levels were increased in clinical non-responders (287.3 [127.9-438] pg/mL) compared to responders (24.1 [23.2-53.4] pg/mL, p < 0.001), and showed great recognition ability with an AUC of 0.898. CONCLUSIONS The newly developed methodology of CLIA had great potential for use in the clinic. Elevated serum OSM expression was a promising biomarker of severe disease and infliximab non-response in IBD patients.