We have recently introduced multiple reaction monitoring (MRM) mass spectrometry as a novel tool for glycan biomarker research and discovery. Herein, we employ this technique to characterize the site-specific glycan alterations associated with primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). Glycopeptides associated with disease severity were also identified. Multinomial regression modelling was employed to construct and validate multi-analyte diagnostic models capable of accurately distinguishing PBC, PSC, and healthy controls from one another (AUC = 0.93 ± 0.03). Finally, to investigate how disease-relevant environmental factors can influence glycosylation, we characterized the ability of bile acids known to be differentially expressed in PBC to alter glycosylation. We hypothesize that this could be a mechanism by which altered self-antigens are generated and become targets for immune attack. This work demonstrates the utility of the MRM method to identify diagnostic site-specific glycan classifiers capable of distinguishing even related autoimmune diseases from one another.

我们最近推出了多反应监测 (MRM) 质谱作为聚糖生物标志物研究和发现的新工具。在此，我们采用这种技术来表征与原发性胆汁性肝硬化 (PBC) 和原发性硬化性胆管炎 (PSC) 相关的位点特异性聚糖改变。还鉴定了与疾病严重程度相关的糖肽。采用多项回归建模来构建和验证能够准确区分 PBC、PSC 和健康对照的多分析物诊断模型 (AUC = 0.93 ± 0.03)。最后，为了研究疾病相关的环境因素如何影响糖基化，我们表征了已知在 PBC 中差异表达的胆汁酸改变糖基化的能力。我们假设这可能是产生改变的自身抗原并成为免疫攻击目标的机制。这项工作证明了 MRM 方法在识别诊断位点特异性聚糖分类器方面的效用，该分类器甚至能够将相关的自身免疫性疾病彼此区分开来。