Oxidative stress-induced apoptosis of bile duct cells in primary biliary cirrhosis

There has been a relative paucity of effort at defining effector mechanisms of biliary damage in PBC. We hypothesize that biliary cells are destroyed secondary to the immunologic relationships of inflammation and biliary epithelial apoptosis and, in particular, that biliary damage is a result of reduced levels of glutathione-S-transferase (GST), the production of hypochlorous acid (HOCl) and its association with eosinophil peroxidase (EPO). To address this issue, we examined the expression of EPO and GST in PBC and control livers and demonstrated an increase of EPO within the portal areas of PBC. We also demonstrated that macrophages have evidence of phagocytosed EPO. Furthermore, we studied the influence of HOCl on apoptosis in cultured human biliary epithelial cells (BEC) as well as the associated activity of Bcl-2, Bax, p-JNK, JNK, p53, Fas and caspase-3. HOC1-induced apoptosis in BEC in a dose-dependent fashion increased the activity of caspase-3 and the expression of p53 and p-JNK. Pretreatment with l-buthionine-(S,R)-sulfoximine, a glutathione (GSH) inhibitor, potentiated the sensitivity of BEC to HOCl-induced apoptosis. We conclude that intracellular GSH reduction leads directly to BEC apoptosis. Modulation of these events will be critical to reduce immune-mediated destruction.     

Ultrastructural changes of bile duct epithelium in primary biliary cirrhosis in relation to progression of bile duct loss

Summary Using wedge liver biopsies from patients with primary biliary cirrhosis (PBC), ultrastructural features of the intrahepatic bile ducts in livers with slight or no bile duct loss were compared with those in livers with advanced bile duct loss and in extrahepatic cholestasis (EHC).Most changes in the biliary epithelium in PBC were similar to those in EHC. Microvillous loss and bleb formation, mitochondrial damage and increase in endoplasmic reticulum and ribosomes were found in PBC irrespective of the degree of bile duct loss, and also in EHC. These changes were present almost equally at any level of the biliary tree, and are presumed to represent a variety of non-specific lesions of biliary epithelial cells. As the loss of bile ducts in PBC progressed, cytoskeletal filaments and cytophagosomes increased in number and basement membranes were more thickened and reduplicated. These changes were more or less conspicuous in smaller branches of the biliary tree, and were also prominent in EHC. They might be causally related to the bile flow disturbance in the liver. Lateral intercellular spaces were irregularly dilated and contained osmiophilic membranous and/or granular material, similar to that found in duct lumena, within and without the basement membrane, and in the cytoplasm of periductal macrophages. Furthermore, pinocytotic vesicles were increased in the biliary cytoplasm facing periphery. These findings suggest possible alteration of the permeability of biliary epithelial cells, probably in the direction from the lumena to the periductal tissue. Such changes were found in PBC livers with virtual absence of bile duct loss, and the significance of this phenomenon is discussed.     

原发性胆汁性肝硬化患者共刺激分子B7-H4的检测及临床意义

目的 探讨原发性胆汁性肝硬化(primary biliary cirrhosis,PBC)患者共刺激因子B7-1t4的表达及其与疾病发病机制的关系.方法 分别采用荧光实时定量PCR法(real-time PCR)、酶联免疫吸附试验(ELISA)及流式细胞术(FCM)检测65名PBC患者外周血单个核细胞(PBMC)B7-H4mRNA表达水平、血清IL-2水平以及CD4+、CD8+ T细胞亚群和T细胞表面B7-H4表达百分率,同时监测抗线粒体抗体(anti-mitochondrial antibody,AMA)及临床各项生化指标的关系.结果 (1)PBC患者PBMC B7-144 mRNA水平及T细胞表面B7-H4表达百分率显著低于非PBC肝硬化组及健康对照组(P<0.01).(2)活化72 h后各实验组及对照组IL-2含量及CD4+、CD8+、CD4+ CD8+T淋巴细胞表达水平均低于活化前,以非PBC肝硬化组与健康对照组降低显著(P<0.05);PBC组IL-2含量及CD4+、CD4+ CD8+ T淋巴细胞表达水平高于非PBC肝硬化组与健康对照组(P<0.01).(3)AMA-M2阳性患者血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、碱性磷酸酶(ALP)及γ-谷氨酰转肽酶(GGT)水平升高,其中ALP及GGT升高显著(P<0.05);AMA-M2阳性患者与阴性患者T细胞表面B7-H4表达百分率差异无统计学意义(P>0.05).结论 共刺激因子B7-H4对PBC患者体内T细胞活化增殖及细胞因子分泌的抑制作用减弱,为研究PBC的发生发展和阐明PBC的发病机制提供了试验资料.     

Lipoteichoic acid may affect the pathogenesis of bile duct damage in primary biliary cirrhosis

Aim: Intrahepatic bile ducts are the targets for inflammation in primary biliary cirrhosis (PBC), but their pathogenesis is not known. Gram-positive bacterial DNA was detected recently in gallbladder bile of PBC patients. In the present study, we assessed the possible pathological role of lipoteichoic acid (LTA), the Gram-positive bacterial cell wall component, in PBC.

Methods: Liver samples, obtained from 20 patients with PBC (stage 1–2 with CNSDC: stage 3–4 with loss of bile ducts = 10:10) and from 13 patients with chronic hepatitis due to hepatitis C virus (CH–C) with lymphocytic cholangitis, were subjected to immunohistochemical staining with polyclonal rabbit anti-LTA as the primary antibody. Serum reactivities to LTA were studied by ELISA. After 1 μg of purified LTA was placed in a 96-well microplate as an antigen, an antibody capture assay was carried out using serum samples from PBC (n = 20), CH–C (n = 13) and healthy subjects (n = 11).

Results: LTA was localized around the sites of chronic non-suppurative destructive cholangitis (CNSDC) in the portal area in stage 1–2 PBC but was not detected in the portal area in CH–C. In stage 3–4 PBC, LTA was localized around sites of ductular proliferation at the periphery of portal tracts. IgM class anti-LTA serum titers were significantly higher in PBC than in CH–C. IgA class anti-LTA serum titers were significantly higher in PBC than in healthy subjects.

Conclusions: In the PBC livers, the profile of immunoreactivity to LTA changed markedly as the disease progressed. Sera from PBC showed higher levels of anti-LTA titers than CH–C (IgM) or from healthy subjects (IgA). The LTA-mediated immune system might affect the initiation and/or progression of PBC.     

Lipoteichoic acid may affect the pathogenesis of bile duct damage in primary biliary cirrhosis

AIM: Intrahepatic bile ducts are the targets for inflammation in primary biliary cirrhosis (PBC), but their pathogenesis is not known. Gram-positive bacterial DNA was detected recently in gallbladder bile of PBC patients. In the present study, we assessed the possible pathological role of lipoteichoic acid (LTA), the gram-positive bacterial cell wall component, in PBC. METHODS: Liver samples, obtained from 20 patients with PBC (stage 1-2 with CNSDC: stage 3-4 with loss of bile ducts = 10:10) and from 13 patients with chronic hepatitis due to hepatitis C virus (CH-C) with lymphocytic cholangitis, were subjected to immunohistochemical staining with polyclonal rabbit anti-LTA as the primary antibody. Serum reactivities to LTA were studied by ELISA. After 1 microg of purified LTA was placed in a 96-well microplate as an antigen, an antibody capture assay was carried out using serum samples from PBC (n = 20), CH-C (n = 13) and healthy subjects (n = 11). RESULTS: LTA was localized around the sites of chronic non-suppurative destructive cholangitis (CNSDC) in the portal area in stage 1-2 PBC but was not detected in the portal area in CH-C. In stage 3-4 PBC, LTA was localized around sites of ductular proliferation at the periphery of portal tracts. IgM class anti-LTA serum titers were significantly higher in PBC than in CH-C. IgA class anti-LTA serum titers were significantly higher in PBC than in healthy subjects. CONCLUSIONS: In the PBC livers, the profile of immunoreactivity to LTA changed markedly as the disease progressed. Sera from PBC showed higher levels of anti-LTA titers than CH-C (IgM) or from healthy subjects (IgA). The LTA-mediated immune system might affect the initiation and/or progression of PBC.     

T cell targeting and phagocytosis of apoptotic biliary epithelial cells in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is characterized by loss of tolerance against ubiquitously expressed mitochondrial autoantigens followed by biliary and salivary gland epithelial cell (BEC and SGEC) destruction by autoreactive T cells. It is unclear why BECs and SGECs are targeted. Previous work demonstrated that the reduced form of the major PBC autoantigen predominated in apoptotic BECs and SGECs as opposed to an oxidized form in other apoptotic cells. This led to the hypothesis that presentation of novel self-peptides from phagocytosed apoptotic BECs might contribute to BEC targeting by autoreactive T cells. The effect of autoantigen redox status on self-peptide formation was examined along with the phagocytic ability of BECs. Oxidation of PBC autoantigens first was shown to be due to protein S-glutathionylation of lipoyllysine residues. Absence of protein S-glutathionylation generated novel self-peptides and affected T cell recognition of a lipoyllysine containing peptide. Liver biopsy staining revealed BEC phagocytosis of apoptotic BECs (3.74+/-2.90% of BEC) was present in PBC (7 of 7 cases) but not in normal livers (0 of 3). BECs have the ability to present novel mitochondrial self-peptides derived from phagocytosed apoptotic BECs. Apoptotic cell phagocytosis by non-professional phagocytes may influence the tissue specificity of autoimmune diseases.     

Hydrophobic bile acids suppress expression of AE2 in biliary epithelial cells and induce bile duct inflammation in primary biliary cholangitis

Understanding the mechanisms of chronic inflammation in primary biliary cholangitis (PBC) is essential for successful treatment. Earlier work has demonstrated that patients with PBC have reduced expression of the anion exchanger 2 (AE2) on biliary epithelial cells (BEC) and deletion of AE2 gene has led to a PBC-like disorder in mice. To directly address the role of AE2 in preventing PBC pathogenesis, we took advantage of our ability to isolate human BEC and autologous splenic mononuclear cells (SMC). We studied the influence of hydrophobic bile acids, in particular, glycochenodeoxycholic acid (GCDC), on AE2 expression in BEC and the subsequent impact on the phenotypes of BEC and local inflammatory responses. We demonstrate herein that GCDC reduces AE2 expression in BEC through induction of reactive oxygen species (ROS), which enhances senescence of BEC. In addition, a reduction of AE2 levels by either GCDC or another AE2 inhibitor upregulates expression of CD40 and HLA-DR as well as production of IL-6, IL-8 and CXCL10 from BEC in response to toll like receptor ligands, an effect suppressed by inhibition of ROS. Importantly, reduced AE2 expression enhances the migration of autologous splenic mononuclear cells (SMC) towards BEC. In conclusion, our data highlight a key functional role of AE2 in the maintenance of the normal physiology of BEC and the pathogenic consequences of reduced AE2 expression, including abnormal intrinsic characteristics of BEC and their production of signal molecules that lead to the chronic inflammatory responses in small bile ducts.     

Frequent cellular senescence in small bile ducts in primary biliary cirrhosis: a possible role in bile duct loss

The pathogenesis of progressive bile duct loss in primary biliary cirrhosis remains unclear. In this study, the involvement of cellular senescence of biliary epithelial cells was examined in liver tissue samples from patients with primary biliary cirrhosis (n = 33), and compared with control diseased and normal livers (n = 83). In addition, cellular senescence was induced by oxidative stress in cultured mouse biliary epithelial cells. Biliary epithelial cells in small bile ducts in primary biliary cirrhosis, especially those in patients presenting with chronic non-suppurative cholangitis, frequently expressed senescence-associated beta-galactosidase, and senescence-associated p16(INK4) and p21(WAF1/CIP). In contrast, senescence-associated markers were rarely expressed in small bile ducts in control livers. The infiltration of myeloperoxidase-positive inflammatory cells into biliary epithelial cell layers was closely associated with the cellular senescence of biliary epithelial cells in early-stage PBC. Cellular senescence of cultured mouse biliary epithelial cells was induced by treatment with H2O2 via the p38MAPK-dependent pathway and nitric oxide-augmented H2O2-induced cellular senescence. Oxidative stress- and nitric oxide-mediated cellular senescence may be involved in bile duct lesions, which are followed by progressive bile duct loss in primary biliary cirrhosis.     

In situ characterization of the cell-surface antigens of the mononuclear cell infiltrate and bile duct epithelium in primary biliary cirrhosis

To analyze the tissue distribution of mononuclear cells and HLA antigens in primary biliary cirrhosis, we studied liver biopsies of 12 patients at different stages of the disease, using the avidin-biotin-peroxidase technique and monoclonal antibodies directed against T and B lymphocytes, T-cell subsets, macrophages, NK/K cells, dendritic cells, and HLA class I and II antigens. To evaluate the proportion of activated T cells we used anti-interleukin-2-receptor antibodies and a double-staining technique for T cells and class II HLA antigens. In all biopsies activated T cells predominated in the portal areas and around the damaged bile ducts. T4 cells almost always outnumbered T8 cells. While B cells, NK/K cells, and dendritic cells were always scarce, macrophages constituted about 30% of the cellular infiltrate. Biliary epithelium, which normally expresses HLA class I antigens, displayed mainly HLA class II antigens. The predominance of T4 cells around the bile ducts, which express class II antigens, suggests that class II-restricted T4 lymphocytes may mediate liver damage in primary biliary cirrhosis.     

Osteopontin is involved in the formation of epithelioid granuloma and bile duct injury in primary biliary cirrhosis

Recently, it was shown that osteopontin (OPN) is involved as a chemoattractant cytokine in the recruitment of macrophages and T lymphocytes in the granulomas of diverse etiologies and also plays an important role in the production of autoantibodies and development of autoimmune diseases. Primary biliary cirrhosis (PBC) is characterized by immune-mediated bile duct damage with frequent epithelioid granulomas. In this study, the expression of OPN was immunohistochemically examined in 25 PBC and 52 control livers. Epithelioid cells within granuloma in PBC expressed OPN variably. These cells were also positive for CD68, suggesting their histiocyte/macrophage lineage. In addition, strong expression of OPN was seen in the cytoplasm of mononuclear cells infiltrating around granulomas and also damaged bile ducts in PBC. The number of such positive mononuclear cells and the ratio of OPN-positive cells/total infiltrating cells in portal tracts were higher in PBC than in controls. The majority of these OPN-positive cells were found to be IgG- or IgM-producing plasma cells. These suggest that in PBC, OPN is an important immune molecule in portal tracts, and contributes to the recruitment of mononuclear cells into epithelioid granuloma and also participates in bile duct injury via B-cell differentiation and plasma cell expansion.     

Expression of Bcl-2 familial proteins is reduced in small bile duct lesions of primary biliary cirrhosis

In primary biliary cirrhosis, biliary epithelial cell death by apoptosis results in progressive bile duct loss. We examined immunohistochemically 4 apoptosis-regulating bcl-2 familial proteins (bcl-2, mcl-1, bcl-X, and bax) in the biliary epithelium in 19 cases of primary biliary cirrhosis. Ten cases of chronic hepatitis C, 9 cases of extrahepatic biliary obstruction, and 10 cases of normal liver were used as a control. Bcl-2 and mcl-1 are inhibitors of apoptosis, bcl-X, probably bcl-XL in biliary epithelial cells, an inhibitor, and bax, a promoter of apoptosis. First, we clarified the distribution of bcl-2 familial proteins on the intrahepatic biliary tree in normal livers. Bcl-2 was detected in the interlobular bile ducts and bile ductules, but not in the large and septal bile ducts in all cases examined. Mcl-1, bcl-X, and bax were diffusely detectable at the any level of the intrahepatic biliary tree, with a staining pattern that was diffuse and cytoplasmic. This distribution pattern was preserved in extrahepatic biliary obstruction. Bcl-2 expression was lost or markedly reduced in the damaged interlobular bile ducts in primary biliary cirrhosis, whereas the reduction was only focal or mild in the bile ducts with hepatitis-associated damage in chronic hepatitis C. Expression levels of mcl-1, bcl-X, and bax were similarly reduced to that of bcl-2 in these 2 diseases. These findings suggest that bax is not important as a proapoptotic factor in the damaged bile ducts and that downregulation of bcl-2 and mcl-1, and probably that of bcl-XL, leads to a decrease in the threshold of apoptosis and increase in the vulnerability to apoptotic stimuli in these bile ducts, followed by the progressive apoptotic loss of interlobular bile ducts, in primary biliary cirrhosis.     

Circulating activated B cells in primary biliary cirrhosis

Since patients with primary biliary cirrhosis (PBC) have evidence of abnormal function of the humoral immune system, we determined if B cells from patients with this disease show evidence of activation and can be stimulated by polyclonal activators. Using a reverse hemolytic plaque assay, it was found that patients with PBC had a significant increase in the number of circulating immunoglobulin-secreting cells, compared to normal controls and patients with chronic type B hepatitis virus (HBV) infection. However, the total number of activated cells was less than 1% of the total circulating B-cell population. Furthermore, we were unable to detect an increase in the expression of transferrin receptors, a membrane receptor associated with B-cell activation, in the majority of B cells in patients with PBC. In other studies, immunoglobulin production by lymphocytes from patients with PBC, when stimulated with the polyclonal activators pokeweed mitogen and Epstein-Barr virus (EBV), was reduced. This hyporesponsiveness was not due to a decrease in the number of B cells, as determined by staining with the monoclonal antibody anti-Leu 12. Furthermore, the decreased response of B cells to polyclonal activation in PBC patients was not due increased suppressor T-cell function, since EBV-stimulated cultures of lymphocytes from patients with PBC demonstrated diminished suppression of immunoglobulin-secreting cells after 14 days of culture compared to controls. These findings suggest that the humoral abnormalities in PBC are due to the activation of a small subpopulation of B cells rather than to generalized B-cell hyperactivity.     

Blockade of endogenous B7-H1 suppresses antibacterial protection after primary Listeria monocytogenes infection

B7-H1 (also known as CD274 and PD-L1) is a cosignalling molecule regulating T-cell immunity positively or negatively in vivo. However, little is known about the role of endogenous B7-H1 in bacterial infection. We found that B7-H1 expression was up-regulated in various cell populations including CD4+ and CD8+ T cells, natural killer (NK) cells and macrophages following Listeria monocytogenes infection. Administration of the antagonistic B7-H1 monoclonal antibody resulted in a significant increase in mortality in mice infected with a lethal dose of L. monocytogenes compared with mice given the control immunoglobulin. In vivo blockade of B7-H1 greatly inhibited the production of tumour necrosis factor (TNF)-alpha and nitric oxide, key effector molecules responsible for intracellular killing by macrophages. B7-H1 blockade also suppressed the expression of granzyme B and interferon (IFN)-gamma by NK cells. Interestingly, blocking of endogenous B7-H1 selectively inhibited CD8+ T cells rather than CD4+ T cells in response to L. monocytogenes infection, as evidenced by the reduction of IFN-gamma production and the expression of effector surface markers including CD62L(int/low) and CD44(high) in CD8+ T cells from mice given anti-B7-H1 monoclonal antibody. In addition, we found that the proliferation of listeriolysin-O (LLO)-specific and IFN-gamma-producing L. monocytogenes-reactive CD8+ T cells was significantly decreased not only in the effector phase but also in the memory phase in the presence of anti-B7-H1 antibody. Our findings thus suggest that endogenous B7-H1 can provide positive costimulatory signals for innate and adaptive immunity leading to protection against intracellular bacterial infection.     

T cell immunity and primary biliary cirrhosis

T lymphocytes play a pivotal role in the autoimmune response in primary biliary cirrhosis (PBC). Recent studies have shown that there is overlapping in the PDC-E2-specific T and B cell epitopes. In addition, helper T and cytotoxic T cell epitopes all contain a shared peptide sequence. In addition, recognition of exogenous antigens including bacterial antigens by autoantigen-specific T cell and the mechanism of molecular mimicry provide a clue to clarifying the pathogenesis of PBC. Furthermore, the findings that autoantigen-immune complexes cross present and also that the presentation of autoantigen is of a higher relative efficiency, define a unique role of autoantibodies in the pathogenesis of the autoimmune disease. The mechanism of immune-mediated bile duct damage in PBC, including the possible role of T cell-mediated cytotoxicity and molecular mimicry is discussed.     

Expression of co-stimulatory factor B7-2 on the intrahepatic bile ducts in primary biliary cirrhosis and primary sclerosing cholangitis: an immunohistochemical study

Co-stimulatory factors B7-1 (CD80) and B7-2 (CD86) and their ligands, including CD28, are important for the efficient presentation and persistence of an antigen-specific immune reaction. Hitherto, there has been a paucity of data on the roles of such co-stimulatory factors in immune-mediated biliary diseases. In this investigation, the hepatic immunohistochemical expression of B7-1 and B7-2 has been studied, with emphasis on intrahepatic biliary epithelia, using wedge biopsies from 22 patients with primary biliary cirrhosis (PBC), seven with primary sclerosing cholagitis (PSC), and, as controls, eight cases of extrahepatic biliary obstruction, eight of chronic viral hepatitis C, and three histologically normal livers. In 10/22 (45 per cent) patients with PBC and 3/7 (43 per cent) patients with PSC, B7-2, but not B7-1, was expressed on the epithelial cells of small intrahepatic bile ducts and bile ductules. This expression was manifest as diffuse but variable cytoplasmic staining. Such B7-2-positive bile ducts were not seen in controls. Positive staining was found only in the early stage of PBC and PSC. In PBC and PSC, almost all lymphocytes in the portal tracts, including those around the damaged bile ducts, were positive for CD28, a ligand of B7-2. These results suggest that B7-2 expression on biliary epithelial cells is involved in antigen presentation and perhaps in bile duct destruction in PSC and PBC. Copyright © 1998 John Wiley & Sons, Ltd.     

针对B7-H1的siRNA对脑胶质瘤U87细胞增殖和凋亡的影响

目的:利用针对B7-H1的siRNA在脑胶质瘤U87细胞中下调B7-H1的表达,研究B7-H1的表达下调对U87细胞增殖和凋亡的影响。方法:根据人B7-H1的mRNA序列设计并合成两对针对B7-H1的siRNA,于转染前一天将U87细胞接种于10 cm细胞培养皿中,以转染时细胞融合度为50%-80%为宜,分别用250μl OPTI-MEM稀释15μl siRNA与15μl转染试剂Lipofectamine 2000,将两者混匀室温静置20 min后,滴入细胞培养皿中。转染60或72 h后利用流式细胞术检测B7-H1在细胞表面的表达情况,利用荧光定量PCR和Western Blot分别检测B7-H1的mRNA和蛋白质水平,并用MTT和流式细胞术检测B7-H1表达下调后,U87细胞增殖和凋亡的改变。结果:与阴性对照组相比,两对针对B7-H1的siRNA均可有效下调U87细胞中B7-H1的表达,流式细胞术结果显示与阴性对照组相比,B7-H1阳性表达率由53.2%分别下调至26.7%和20.6%;MTT结果显示B7-H1表达下调后U87细胞的增殖被显著抑制,培养第5天吸光度值由0.58±0.02分别下降至0.451±0.02及0.342±0.016;流式细胞术结果显示B7-H1表达下调后U87细胞凋亡明显,早期凋亡率由0.1%分别增加至12.8%及13.2%。结论:B7-H1的表达下调可有效抑制脑胶质瘤U87细胞的增殖,并促进细胞凋亡,提示B7-H1可能作为脑胶质瘤基因治疗的一个潜在靶点。     

Bile duct epithelia as target cells in primary biliary cirrhosis and primary sclerosing cholangitis

 Primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) are chronic autoimmune-mediated diseases of the biliary tree, resulting in a loss of bile ducts. There are morphological features that clearly distinguish them from each other: in PBC, there is overt destruction of the bile ducts with disruption of the basement membrane; in PSC there is abundant periductular fibrosis with shrinkage and subsequent loss of the bile ducts. In order to see if the disparate histopathology is paralleled by different immunohistology we looked at a panel of epitopes on bile duct epithelia especially to see if biliary epithelial cells may present as targets for cell mediated immune respone. In PBC bile duct epithelial cells mostly expressed CD58 (lymphocyte function-associated antigen 3), CD80 (B7 BB1), and CD95 (Fas). In PSC, however, these epitopes were only expressed in a few examples to a lower degree. The respective effector T lymphocytes were positive for CD2 and CD28. Subtyping of the lymphocytes in the liver tissue further showed a predominance of CD4 positive T cells over CD8 cells up to 2-to-1 in both diseases. Determination of lymphocytes by cytokines to Th1 or Th2 subtype showed a majority of Th1 lymphocytes in PBC and PSC. We conclude that in PBC bile duct epithelial cells may display features of target cells of a T cell-mediated immune reaction with the Th1 cells predominating. In PSC other mechanisms of bile duct loss may play a role, since in this disease the majority of cells lack essential epitopes that constitute targets of cell mediated immunity. Received: 19 November 1996 / Accepted: 26 February 1997     

Distal common bile duct stricture and secondary biliary cirrhosis due to choledocholithiasis.

This case report documents a patient who presented with retained common bile duct (CBD) stones, recurrent attacks of cholangitis, CBD stricture, and secondary biliary cirrhosis. Endoscopic or surgical treatment of choledocholithiasis must be considered early in treatment.