Alteration of serum N-glycan profile in patients with autoimmune pancreatitis

Objectives: The aims of this study were to determine the change in whole-serum N-glycan profile in autoimmune pancreatitis (AIP) patients and to investigate its clinical utility. Methods: We collected serum from 21 AIP patients before any treatment, and from 60 healthy volunteers (HLTs). Serum glycan profile was measured by comprehensive and quantitative high-throughput glycome analysis. Results: Of the 53 glycans detected, 14 were differentially expressed in AIP patients. Pathway analysis demonstrated that agalactosyl and monogalactosyl bi-antennary glycans were elevated in AIP patients. Among the 14 glycans, #3410, #3510, and #4510 showed high area under receiver operating characteristic (AUROC) values (0.955, 0.964, and 0.968 respectively) for the diagnosis of AIP. These three glycans were mainly bound to immunoglobulin G; however, their serum levels were significantly higher, even in AIP patients who showed lower serum IgG4 levels, than in HLTs. Conclusions: We demonstrated, for the first time, whole-serum glycan profiles of AIP patients and showed that the levels of glycans #3410, #3510, and #4510 were increased in AIP patients. These glycans might be valuable biomarkers of AIP.