Objective: To explore the effect of cathepsin (Cat) S in primary biliary cholangitis (PBC). Methods: The serum of PBC patients and Hepatitis B virus (HBV) patients were collected in Peking Union Medical College Hospital from August 2016 to July 2017 and the liver tissue of PBC were collected from March 2010 to July 2013. Indirect enzyme-linked immunosorbent assay (ELISA) was used to detect the serum concentrations of total-and pro-Cat S respectively in 24 PBC patients, 24 Hepatitis B patients and 24 healthy controls. The relation between the serum levels of Cat S and cholestasis biochemical indexes and the serum levels of immunoglobulin (Ig) M, G were analyzed. Immunofluorescence analysis of liver tissue was performed to detect macrophage infiltration and Cat S expression. The data was analyzed by student's t-test, spearman correlation analysis, and receiver operating characteristic (ROC) curve was used to obtain an optimal cutoff value. Results: The serum levels of total-Cat S, pro-Cat S and active-Cat S in PBC group were significantly higher than those in healthy controls and HBV controls (P<0.05). There was a correlation between serum total-Cat S and ALP and GGT in patients with PBC (P<0.05). There was a moderate correlation between pro-Cat S and ALP and GGT (P<0.05) and total Cat S was associated with IgG (P<0.05). The area under ROC curve (AUC) of total-Cat S, pro-Cat S and active-Cat S was 0.85(P<0.01), 0.65(P<0.05) and 0.77(P<0.01), respectively. The optimal cut-off value was 11.30、7.81 and 5.93 pg/L, respectively, with the sensitivity of 0.81, 0.53 and 0.53 and specificity of 0.82, 0.81 and 0.96. Liver tissue immunofluorescence revealed macrophage infiltration in the liver of PBC patients. The average percentage of macrophages and Cat S co-expressed cells in mononuclear cells was 23.77%. Conclusion: The expression of Cat S in serum of patients with PBC is significantly higher than that of healthy controls and HBV patients, and is related to IgG and serum ALP, r-GT levels. Liver tissue macrophages were co-expressed with Cat S. Cat S may participate in the process of antigen presentation in the pathogenesis of PBC.
目的： 探讨组织蛋白酶（Cat）S在原发性胆汁性胆管炎（PBC）中的作用。 方法： 收集2016年8月至2017年7月于北京协和医院就诊的PBC及乙型肝炎（HBV）患者血清，2010年3月至2013年7月在北京协和医院住院的PBC患者肝脏穿刺标本。通过酶联免疫吸附法（ELISA）检测PBC患者、HBV患者及健康对照血清总Cat S和pro-Cat S水平，计算活性形式active-Cat S，并分析PBC患者血清Cat S与胆汁淤积生化指标、IgM、IgG之的相关性；通过免疫荧光检测肝脏组织巨噬细胞浸润及Cat S表达。采用受试者工作特征曲线（ROC曲线）、t检验、Spearman相关性分析进行统计学分析。 结果： PBC组患者血清总Cat S、pro-Cat S、active-Cat S表达水平均高于健康对照组和HBV组患者，差异有统计学意义（P<0.05）。PBC患者血清总-Cat S与碱性磷酸酶（ALP）、谷氨酰转肽酶（GGT）、IgG之间具有相关性（P<0.05）；pro-Cat S与ALP、GGT相关（P<0.05）。采用受试者工作特征曲线分析发现，血清总Cat S、pro-Cat S和active-Cat S的曲线下面积（AUC）分别为0.85（P<0.01）、0.65（P<0.05）和0.77（P<0.01）；最佳阈值分别为11.30、7.81及5.93 pg/L；敏感性和特异性分别为0.81和0.82、0.53和0.81、0.53和0.96。肝脏组织免疫荧光显示，PBC患者肝脏中存在巨噬细胞浸润，巨噬细胞和Cat S共表达占单个核细胞的平均百分比为23.77%。 结论： PBC患者血清Cat S表达较健康对照和HBV患者明显增加，与血清IgG和ALP/GGT水平相关。肝脏组织巨噬细胞与Cat S共表达。Cat S可能参与PBC发病中抗原提呈过程。.
Keywords: Antigen presentation; Biomarker; Cathepsin S; Primary biliary cholangitis.