Mechanism of Bile Duct Destruction in Primary Biliary Cirrhosis

1)制备抗细胞角蛋白CK1亚类(52KD)的单抗。采用抗CK1抗体的间接免疫过氧化物酶方法，检测原发性胆汁性肝硬变(PBC)患者和非黄褐性胆石症患者的腹腔镜肝活检标本中CK1的表达。抗线粒体抗体阳性和阴性的慢性非化脓性破坏性胆管炎患者胆管间隔和小叶间胆管上皮细胞中CK1异常表达，而对照组肝内胆管中CK1不表达，提示CK1可能是触发针对胆管间隔和小叶间胆管的自身免疫破坏反应的表位。(2)细胞间黏附分子(ICAM-1)及其配体和淋巴细胞功能相关抗原(LFA-1)的免疫组织化学…表达在PBC组和对照组的楔形肝活检标本中，ICAM-1仅在肝窦内皮细胞表达。ICAM-1在小叶间胆管和间隔胆管上皮细胞质膜中异常表达，尤其是在淋巴细胞密集浸润性胆管上皮细胞质膜的基底部。LFA-1在CNSDC胆管周围密集浸润的淋巴细胞表面呈强阳性表达。部分LFA-1阳性的淋巴细胞直接附着在胆管上皮细胞质膜的基底部。免疫过氧化物酶染色显示，损伤胆管内皮细胞的基底面和侧面可见部分CD4阳性、CD8阳性的淋巴细胞。此外，在CNSDC的导管上皮细胞中，不仅有人类白细胞抗原-A、B、C的表达增强，而且有人类白细胞抗原-DR的异常表达。基于上述发现，活化的CD4阳性(MHC II类限制性)和CD8阳性(MHC I类限制性)T细胞在人类白细胞抗原DR的异常表达和人类白细胞抗原A、B、B的增强下，可直接或间接作用于小叶和间隔胆管的靶上皮细胞。另一项研究旨在阐明熊去氧胆酸(UDCA)治疗对PBC患者血清抗CK-1抗体滴度和PBC患者血清中可溶性(S)-ICAM-1水平的影响。UDCA治疗1个月后，血清抗CK1滴度和S-ICAM-1水平均显著下降，24个月后维持在较低水平，提示长期UDCA治疗可能参与改善自身免疫性胆管的破坏。较少

1) The monoclonal antibody was produced against cytokeratin subclass CK1 (52KD) obtained from the successive human cultured cell line PtK_2. By the indirect immunoperoxidase method using anti - CK1 antibody, the expressions of CK1 were examined in the laparoscopic wedged liver biopsy specimens from patients with primary biliary cirrhosis (PBC) and from those with non - icteric cholelithiasis. CK1 was aberrantly expressed in the septal and interlobular bile duct epithalial cells featured by chronic nonsuppurative destructive cholangitis (CNSDC) in antimitochomdrial antibody (AMA)-positive and AMA-negative PBC, while CK1 was not expressed throughout the intrahepatic biliary tract in the conrtol, implying that CK1 may play a role as "an epitope" to triggre the autoimmune destructive response targeting the septal and interlobular bile ducts in PBC.2) Imnunohistochemical expressions of intercellular adhesion molecule (ICAM-1) and its ligand, lymphocyte function-associated antigen (LFA-1) we … More re examined in the wedged liver biopsy specimesd in PBC and in the control as above, while ICAM-1 was expressed only in the hepatic sinusoidal endothelial cells in the control. ICAM-1 was aberrantly expressed in the epithelial cell plasma membranes of the interlobular and septal ltle ducts, particularly in the basal site of the epithelial cell plasma membranes of the bile ducts intensely infiltrated with lymphocytes. LFA-1 was strongly expressed on the surfaces of lymphocytes intensely infiltrated around the bile ducts showing CNSDC. Some of the LFA-1-povitive lynphocytes were found to be directly attached on the basal sites of the bile ducts epithelial cell plasma membranes. Some of the CD4-positive, CD8-positive lymphocytes identified by the immunoperexidase method were evident on the basal and lateral surface of the injured bile duct elithelial cells. Moreover, not only the enhanced expressions of HLA-A, B and C but also the aberrant expressions of HLA-DR were noted in the duct epithelial cells showing CNSDC. Based on the above findings, both of the activated CD4-positive (MHC class II-restricted) and CD8-positive (MHC class I-restricted) T cells would directly or indirectly act on the target epithelial cells of the interlobular and septal bile duct under the aberrant expression of HLA-DR and the enhancement of HLA-A, B, C. The interactions between the ICAM-1 on the bile duct epithelium and the LFA-1 on CD4-positive and CD8-positive lymphocyte surfaces is considered to be a key immune process for the bile duct destruction in PBC.3) Another study was conducted to elucidate how ursodeoxycholic acid(UDCA) therapy (600mg/day) for PBC patients affects the serum anti-CK-1 antibody titers determined by sandwich inhibition ELISA as well as the soluble(s)-ICAM-1 levels determined by ELISA in the sera of PBC patients, reflecting the above immunchistorhemical expressions of ICAM-1. Both of the anti-CK1-titers and s-ICAM-1 levels were significantly decraosed one month after the treatment with UDCA, and maintained at the lower levels during the twenty four months of UDCA treatment, indicating that the long-term UDCA therapy would be involved in the improvement of autoimmune bile duct destruction. Less