Detection of circulating intercellular adhesion molecule-1 in chronic liver diseases.

The leucocyte adhesion molecule intercellular adhesion molecule-1 is induced on bile ducts in patients with primary biliary cirrhosis and primary sclerosing cholangitis and may be involved in targeting immune damage to these structures. It has recently been reported that, when activated, in vitro lymphocytes release a soluble form of intercellular adhesion molecule-1 that can also be detected in human serum. Because it is functionally active, this circulating intercellular adhesion molecule-1 might play a role in regulating inflammation by blocking adhesion. We used an enzyme-linked immunosorbent assay to detect circulating intercellular adhesion molecule-1 in the serum of patients with primary biliary cirrhosis and primary sclerosing cholangitis. Levels of circulating intercellular adhesion molecule-1 were markedly elevated in primary biliary cirrhosis and primary sclerosing cholangitis when compared with other chronic liver diseases. Circulating intercellular adhesion molecule-1 is probably derived from activated lymphocytes rather than from bile ducts because biliary epithelial cells from patients with primary biliary cirrhosis did not release circulating intercellular adhesion molecule-1 when stimulated to express the membrane-bound molecule in vitro. These studies are the first to demonstrate circulating intercellular adhesion molecule-1 in chronic inflammatory diseases that are characterized by strong tissue expression of intercellular adhesion molecule-1 and as such suggest a potential immunoregulatory role for circulating adhesion molecules. The very high levels detected in primary biliary cirrhosis and primary sclerosing cholangitis probably reflect lymphocyte activation, which is further evidence of immune pathogeneses for these diseases.     

Chronic intrahepatic cholestasis of sarcoidosis.

The development of the syndrome of chronic intrahepatic cholestasis in five young, black men who had systemic granulomatous disease and clinical features consistent with those of sarcoidosis is described. Clinical and biochemical aspects, similar to those of primary biliary cirrhosis, included pruritus, jaundice, hepatomegaly and striking elevations of serum levels of alkaline phosphatase and cholesterol. (One patient had skin xanthomas.) Mitochondrial antibodies were not found; and survival of the patients (7 to 18 years) exceeded the usual survival of patients with primary biliary cirrhosis. The histologic abnormalities included noncaseating granulomas, chronic intrahepatic cholestasis, increased copper in hepatocytes, progressive diminution in number of interiobular bile ducts, periportal fibrosis and the eventual development of a micronodular "biliary" cirrhosis. The histologic evolution of the disease suggests a slow, progressive destruction of the bile ducts by granulomas. Although the end stage of this syndrome resembles primary biliary cirrhosis, the characteristic nonsuppurative, destructive cholangitis of primary biliary cirrhosis was not present.     

Lack of Concomitant Expression of ICAM-1 and HLA-DR on Bile Duct Cells from Patients with Primary Sclerosing Cholangitis and Primary Biliary Cirrhosis

In both primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC) prominent infiltrates of lymphocytes surround the bile ducts, on which an abberrant expression of major histocompatibility complex class II antigens has been found, suggesting that the immune system is involved in the biliary destruction. Since the lymphocytes presumably must adhere to the bile ducts to initiate a cell-to-cell-mediated destruction, we have studied the expression of the lymphocyte function-associated antigen-1 (LFA-1) together with its ligand, the intercellular adhesion molecule-1 (ICAM-1), and the expression of HLA-DR, using immunoperoxidase staining of cryostat sections from patients with PBC (n = 10), PSC (n = 13), and normal healthy controls (n = 6). Most lymphocytes expressed LFA-1. ICAM-1 expression was found on hepatocytes from 9 of 10 PBC and 10 of 13 PSC patients but was not seen on hepatocytes from the controls. Hepatocytes expressing HLA-DR were only found in one patient with PBC. None of the septal bile ducts expressed ICAM-1, and only one PSC patient and three PBC patients expressed ICAM-1 on their interlobular bile ducts. The bile ducts in 22 of 23 patients, however, expressed HLA-DR. Proliferating bile ductules from two PBC patients and three PSC patients showed a concomitant expression of ICAM-1 and HLA-DR. None of the bile ducts from the controls expressed ICAM-1 or HLA-DR. Thus, since most bile ducts involved in the disease process of both PBC and PSC lack expression of ICAM-1, other adhesion molecules must be involved if a cell-to-cell-mediated destruction accounts for the biliary destruction in these two disease states. Furthermore, the lack of concomitant expression of HLA-DR and ICAM-1 on the bile ducts in PBC and PSC indicates that other regulatory mechanisms exist in the biliary epithelium than in most other epithelial cells.     

Ultrastructural immunocytochemical analysis of lymphocytes infiltrating bile duct epithelia in primary biliary cirrhosis

Subpopulations of lymphocytes in portal areas, especially infiltrating bile duct epithelia were analyzed by light and electron microscopy using indirect peroxidase-labeled antibody method and monoclonal antibodies against pan-T (Leu 1), cytotoxic/suppressor T (Leu 2a), helper/inducer T (Leu 3a) and natural killer/K (Leu 7) and suppressor T (Leu 15) cells in liver biopsy specimens from four patients with primary biliary cirrhosis. Bile ducts with chronic nonsuppurative destructive cholangitis were observed in two patients. Leu 1+ and Leu 2+ cells were frequently seen in intimate contact with epithelial ductal cells. The majority of intraepithelial cells possessing Leu 2a antigen did not react with anti-Leu 15 antibody. Leu 3a+ or Leu 7+ cells seldom infiltrated ductal epithelia. These findings indicate that the majority of intraepithelial lymphocytes in bile ducts most likely represent Leu 2a+15- cytotoxic T cells. By immunoelectron microscopy, Leu 1+ or Leu 2a+ lymphocytes often breached the basement membrane of bile ducts and were present within dilated intercellular spaces between biliary epithelial cells. Furthermore, they often formed sharp or broad contacts with the epithelial cells, and occasionally pseudopods projecting from the surfaces of Leu 2a+ cells extended into the epithelial cells. Most of Leu 2a+ lymphocytes contained little cytoplasm with few granules and a small Golgi apparatus. Such findings suggest that cytotoxic T cells may contribute to the pathogenesis of chronic nonsuppurative destructive cholangitis in primary biliary cirrhosis.     

Expression of intercellular adhesion molecule-1 and lymphocyte function-associated antigen-1 protein and messenger RNA in primary biliary cirrhosis

OBJECTIVE: This study examined the role of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) in the autoimmune process of bile duct destruction in the early stages of primary biliary cirrhosis (PBC). MATERIALS AND METHODS: Ten PBC liver samples and five control samples were studied. Immunohistochemical studies of ICAM-1 and LFA-1, and Western blot of ICAM-1 were performed. Immunoelectron microscopy was conducted using immunoglobulin-gold and silver staining. Human ICAM-land LFA-1 peptide nucleic acid probes were used for in situ hybridization. RESULTS: In PBC liver samples, immunohistochemistry showed aberrant ICAM-1 expression on bile duct epithelial plasma membrane and also luminal sites of endothelial plasma membrane of terminal portal venules. Western blot confirmed ICAM-1 protein expression. LFA-1-positive lymphocytes were associated with epithelial cells of septal and interlobular bile ducts. Immunoelectron microscopy localized ICAM-1 on the luminal and basal surfaces as well as on lymphocytes around damaged bile duct epithelial cells, and LFA-1 on lymphocytes around damaged bile ducts. Messenger RNA expression of ICAM-1 was demonstrated in bile ducts, and LFA-1 in lymphocytes around bile ducts. CONCLUSION: De novo expression of ICAM-1 and LFA-1 at protein and mRNA levels in PBC may imply an inductive role of ICAM-1 through binding with its ligand LFA-1 in the extravasation of activated lymphocytes and lymphocyte-mediated bile duct destruction.     

Frequent expression of MUC1 apomucin on biliary epithelial cells of damaged small bile ducts in primary biliary cirrhosis and chronic viral hepatitis: An immunohistochemical study

MUC1 apomucin is a specific target tumor antigen recognized by cytotoxic T cells in a major histocompatibility complex (MHC) unrestricted fashion in patients with pancreatic and breast cancer. This T-cell-mediated immune mechanism against MUC1 apomucin expressing cells has not been evaluated in nonneoplastic immune-mediated diseases. Therefore, we immunohistochemically surveyed the expression of MUC1 apomucin on biliary epithelial cells of small bile ducts in various hepatobiliary diseases, including primary biliary cirrhosis (PBC). MUC1 apomucin was detected using the monoclonal antibody DF3 and the streptavidin-biotin complex, in livers from 31 patients with PBC, 67 with chronic viral hepatitis (CH) with or without cirrhosis, 31 with extrahepatic biliary obstruction (EBO), 30 with hepatolithiasis, and from 23 normal individuals. MUC1 apomucin was infrequently and focally expressed in the biliary epithelial cells of the small bile ducts in 3 of 23 normal livers. In contrast, MUC1 apomucin was frequently and strongly expressed on the luminal surface of biliary epithelia] cells of small bile duct, in 22 of 31 patients with PBC, and in 50 of 67 patients with CH. In particular, high levels of MUC1 apomucin were expressed in bile ducts showing chronic nonsuppurative destructive cholangitis (CNSDC) in PBC and hepatitic duct injuries in CH. In EBO and hepatolithiasis, MUC1 apomucin was focally and weakly expressed in 29% and 30% of livers examined, respectively. More MUC1 apomucin was expressed in PBC and CH than in EBO, hepatolithiasis, and normal liver (P < .01, respectively). Frequent and high luminal expression of MUC1 apomucin on biliary epithelial cells in damaged small bile ducts in PBC and CH may be related to T-cell-mediated immunologic mechanisms in these diseases, probably by an MHC-unrestricted recognition process. (Hepatology 1996 Jun;23(6):1313-7)     

Immunopathogenesis of primary sclerosing cholangitis: possible role of a shared colonic and biliary epithelial antigen

Abstract   Primary sclerosing cholangitis (PSC) is a chronic fibrosing disease of both extrahepatic as well as intrahepatic bile ducts that is strongly associated with inflammatory bowel disease, particularly ulcerative colitis. It is characterized by progressive destruction of the bile ducts leading to widespread biliary obstructions and biliary cirrhosis. PSC is currently one of the more common indications for liver transplantation. It is an immune mediated disorder associated with autoantibodies against both colon epithelium as well as biliary epithelium, infiltration of the portal tract with functional T cells, abnormal expression of HLA molecules on biliary epithelial cells and a restricted T-cell receptor repertoire. Activation of the complement system, following the deposition of antigen-specific autoantibody with biliary epithelial cells, may also contribute to the pathogenesis of PSC. Four different HLA haplotypes have been associated with PSC: three with increased risk of disease and one with reduced risk. Bacterial products entering the biliary epithelium from colon may be a triggering factor strongly associated with ulcerative colitis; however, a further immune mediated chronic inflammation may be associated with cellular antigen(s) which is shown to be shared by human colon and biliary epithelium by molecular mimicry.     

Intrahepatic bile duct loss in immune-mediated ductopenic biliary diseases with an emphasis on biliary epithelial apoptosis

The biliary epithelial apoptosis is thought to be a major pathogenic process of bile duct loss in a number of immune-mediated ductopenic biliary diseases, though its exact mechanism and process seem still speculative. Clarification of pathologic microenvironments around the bile ducts as well as pathobiology of biliary epithelial cells undergoing apoptosis in these diseases are mandatory. Several steps and mechanisms during induction and progression of biliary epithelial apoptosis followed by bile duct loss are now being proposed in immune-mediated ductopenic biliary diseases: 1) the presentation of target antigens including autoantigen(s) in biliary epithelial cells; 2) network of cytokine and its imbalance around the damaged bile ducts; 3) migration of immune-competent cells into the biliary layer followed by cell-to-cell and cell-to-matrix interaction and antibody-mediated cell dysfunction of biliary epithelial cells; and 4) increased susceptibility and decreased threshold for biliary epithelial apoptosis and aggravation of biliary epithelial apoptosis by infectious agents. We review here the pathogenetic processes of immune-mediated ductopenic biliary diseases.     

Histometric and serial section observations of the intrahepatic bile ducts in primary biliary cirrhosis.

Histometric examinations, based on the assumption that hepatic arterial branches and bile ducts run parallel within the portal tracts, suggest that in primary biliary cirrhosis bile ducts with a lumen (the smallest diameter between the subepithelial basal membranes) below 70--80 micron are destroyed. The smaller the ducts, the more they destroyed. Extensive destruction of the ducts was seen more frequently in the nonfibrotic stage of primary biliary cirrhosis than in later stages. Serial sections of the intrahepatic bile ducts in primary biliary cirrhosis revealed three types of periductal lesions preceding the disappearance of bile ducts: (A) periductal cellular reaction including features of chronic nonsuppurative destructive cholangitis, (B) periductal edema, and (C) periductal fibrosis. In the nonfibrotic stage, types A and C were frequent, whereas in the fibrotic stage types A and B were increased, and type C was predominant in the cirrhotic stage.     

Peptide antibiotic human beta-defensin-1 and -2 contribute to antimicrobial defense of the intrahepatic biliary tree

Human beta-defensins (hBDs) are important antimicrobial peptides that contribute to innate immunity at mucosal surfaces. This study was undertaken to investigate the expression of hBD-1 and hBD-2 in intrahepatic biliary epithelial cells in specimens of human liver, and 4 cultured cell lines (2 consisting of biliary epithelial cells and 2 cholangiocarcinoma cells). In addition, hBD-1 and hBD-2 were assayed in specimens of bile. hBD-1 was nonspecifically expressed immunohistochemically in intrahepatic biliary epithelium and hepatocytes in all patients studied, but expression of hBD-2 was restricted to large intrahepatic bile ducts in 8 of 10 patients with extrahepatic biliary obstruction (EBO), 7 of 11 with hepatolithiasis, 1 of 6 with primary biliary cirrhosis (PBC), 1 of 5 with primary sclerosing cholangitis (PSC), 0 of 6 with chronic hepatitis C (CH-C), and 0 of 11 with normal hepatic histology. hBD-2 expression was evident in bile ducts exhibiting active inflammation. Serum C reactive protein levels correlated with biliary epithelial expression of hBD-2. Real-time PCR revealed that in all of 28 specimens of fresh liver, including specimens from patients with hepatolithiasis, PBC, PSC, CH-C and normal hepatic histology, hBD-1 messenger RNA was consistently expressed, whereas hBD-2 messenger RNA was selectively expressed in biliary epithelium of patients with hepatolithiasis. Immunobloting analysis revealed hBD-2 protein in bile in 1 of 3 patients with PSC, 1 of 3 with PBC, and each of 6 with hepatolithiasis; in contrast, hBD-1 was detectable in all bile samples examined. Four cultured biliary epithelial cell lines consistently expressed hBD-1; in contrast these cell lines did not express hBD-2 spontaneously but were induced to express hBD-2 by treatment with Eschericia coli, lipopolysaccharide, interleukin-1beta or tumor necrosis factor-alpha. In conclusion, these findings suggest that in the intrahepatic biliary tree, hBD-2 is expressed in response to local infection and/or active inflammation, whereas hBD-1 may constitute a preexisting component of the biliary antimicrobial defense system.     

Spontaneous occurrence of autoimmune cholangitis in senescent mice

Abstract The biliary lesions that developed spontaneously in senescent female C57BL/6NCrj mice were investigated. Degeneration of the bile duct epithelium was observed in 12 of 13 mice (92%), destruction of bile duct epithelial cells was seen in six of 13 mice (46%) and chronic non-suppurative destructive cholangitis was found in three of 13 mice (23%). The biliary lesions were characterized by prominent round cell infiltrates in the portal areas. Extra-hepatic lesions such as sialoadenitis were observed in six mice (46%) and pancreatitis in seven (53%). IgM class antipyruvate dehydrogenase antibody was positive in one of three C57BL/6NCrj mice not given anti-Lyt 2 antibody and in three of six C57BL/6NCrj mice injected with anti-Lyt 2 antibody. These lesions were not observed in male C57BL/6NCrj mice, young female C57BL/6NCrj mice, or ICR mice. However, by transferring the splenic cells of senescent female C57BL/6NCrj mice to 6 week old females, the biliary lesions could be transferred at the rate of 6/9. The lymphocytes infiltrating in the bile ducts were CD8 positive lymphocytes. Moreover, in the ultrastructural immunocytochemical analysis of lymphocytes infiltrating bile duct epithelia, CD8 positive lymphocytes often formed broad contacts with the epithelial cells. The biliary lesions developing spontaneously in these mice are similar to those found in human primary biliary cirrhosis.     

Are bile duct lesions of primary biliary cirrhosis distinguishable from those of autoimmune hepatitis and chronic viral hepatitis? Interobserver histological agreement on trimmed bile ducts

Background Primary biliary cirrhosis (PBC) is histopathologically characterized by chronic nonsuppurative destructive cholangitis and ductopenia of interlobular bile ducts. Bile duct injury is also often encountered in chronic viral hepatitis (CVH) and in autoimmune hepatitis (AIH).Methods In this study, we performed interobserver agreement analysis on 90 injured bile ducts from liver specimens of PBC (17 cases), CVH (26 cases), and AIH (18 cases), with 30 bile ducts chosen from each disease group. Digital images of bile ducts with minimal periductal elements were recorded in CD-ROM format and sent to 14 observers (six special hepatopathologists, four local hepatopathologists, and four general pathologists). We analyzed the following issues: (1) diagnostic accuracy of PBC, based only on bile duct lesions; (2) classification of bile duct lesions in AIH cases as destructive cholangitis equivalent to PBC-associated injury, or not.Results The diagnostic accuracy of PBC cases with severe bile duct injuries was very high (over 80%), although the accuracy in cases with only mild bile duct injuries was low (50% or less). For AIH, each observer classified 9 of the 30 bile ducts, on average, as destructive cholangitis.Conclusions This study revealed that 66.9% of PBC cases could be diagnosed based on trimmed bile ducts alone. Bile duct injury similar to that in PBC could be encountered in AIH.     

Apoptosis of biliary epithelial cells in primary biliary cirrhosis and primary sclerosing cholangitis

BACKGROUND/AIMS: Primary biliary cirrhosis (PBC) is an autoimmune disease characterized by inflammatory destruction of small bile ducts. Primary sclerosing cholangitis (PSC) is a different, presumed autoimmune cholestatic liver disease where the bile ducts are also destroyed. In this study, apoptosis and portal triad inflammation in liver tissue from patients with PBC is examined and compared to that from patients with PSC and patients with normal liver. METHODS: Explanted liver tissue from patients with PBC and PSC and normal liver from patients with metastases to liver were examined. The liver samples were stained for apoptosis using the terminal deoxynucleotidyl triphosphate (TdT)-mediated deoxyuridine triphosphate nick end labelling (TUNEL) assay. The biliary epithelial cells (BEC) were then scored on the basis of their TUNEL stain and the degree of periductal inflammation. RESULTS: In PBC, apoptosis of BEC, as detected by the TUNEL assay, was significantly increased in the presence of inflammation. Regardless of the presence or absence of inflammation, the small bile ducts in PBC liver tissue exhibited greater evidence of apoptosis than did similar ducts from PSC or control livers. CONCLUSION: These findings suggest that in PBC, unlike PSC, the apoptosis of BEC in PBC is secondary to the invasion of inflammatory cells.     

Increased expression of intercellular adhesion molecule 1 on bile ducts in primary biliary cirrhosis and primary sclerosing cholangitis.

It has been suggested that immunological mechanisms involving lymphocyte-mediated damage are important in the characteristic bile-duct damage that occurs in primary biliary cirrhosis and primary sclerosing cholangitis. Because adhesion is necessary for the interaction of lymphocytes with their target structures, we have studied the expression of intercellular adhesion molecule 1, a ligand for the leukocyte adhesion receptor lymphocyte function-associated antigen 1 in the liver of patients with primary biliary cirrhosis and primary sclerosing cholangitis. Strong expression of intercellular adhesion molecule 1 was seen on interlobular bile ducts and proliferating bile ductules in both conditions. In primary biliary cirrhosis, medium-sized ducts, which are spared by the disease, were negative. Minimal bile-duct staining was seen in conditions in which bile-duct damage is not a major feature, such as nonbiliary cirrhosis and acute liver diseases. In patients with cirrhosis from any cause, strong expression of intercellular adhesion molecule 1 was detected on the periseptal hepatocytes adjacent to new connective tissue. The intensity of immunohistochemical staining was recorded using a semiquantitative visual scoring system that was subsequently validated quantitatively by confocal laser scanning microscopy. The expression/induction of intercellular adhesion molecule 1 on bile ducts may be important in the pathogenesis of bile-duct damage in primary biliary cirrhosis and primary sclerosing cholangitis and is further evidence to support an immune pathogenesis in these two conditions. Furthermore, the induction of intercellular adhesion molecule 1 on hepatocytes may be an important factor in the liver-cell damage and fibrosis that occur during the development of cirrhosis.     

Interaction between Toll-like receptors and natural killer cells in the destruction of bile ducts in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is characterized by chronic nonsuppurative destructive cholangitis (CNSDC) associated with destruction of small bile ducts. Although there have been significant advances in the dissection of the adaptive immune response against the mitochondrial autoantigens, there are increasing data that suggest a contribution of innate immune mechanisms in inducing chronic biliary pathology. We have taken advantage of our ability to isolate subpopulations of liver mononuclear cells (LMC) and examined herein the role of Toll-like receptors (TLRs), their ligands, and natural killer (NK) cells in modulating cytotoxic activity against biliary epithelial cells (BECs). In particular, we demonstrate that Toll-like receptor 4 ligand (TLR4-L)-stimulated NK cells destroy autologous BECs in the presence of interferon alpha (IFN-α) synthesized by TLR 3 ligand (TLR3-L)-stimulated monocytes (Mo). Indeed, IFN-α production by hepatic Mo is significantly increased in patients with PBC compared to disease controls. There were also marked increases in the cytotoxic activity of hepatic NK cells from PBC patients compared to NK cells from controls but only when the NK cells were prepared following ligation of both TLR3-L- and TLR4-L-stimulated LMC. These functional data are supported by the immunohistochemical observation of an increased presence of CD56-positive NK cells scattered around destroyed small bile ducts more frequently in liver tissues from PBC patients than controls. CONCLUSION: These data highlight critical differences in the varied roles of Mo and NK cells following TLR3-L and TLR4-L stimulation.     

Fractalkine and CX3CR1 are involved in the recruitment of intraepithelial lymphocytes of intrahepatic bile ducts

Fractalkine is a chemokine with both chemoattractant and cell-adhesive functions, and in the intestine it is involved with its receptor CX3CR1 in the chemoattraction and recruitment of intraepithelial lymphocytes. We examined the pathophysiological roles of fractalkine and CX3CR1 in normal and diseased bile ducts. Expression of fractalkine and CX3CR1 were examined in liver tissues from patients with primary biliary cirrhosis (17 cases) and controls (9 cases of primary sclerosing cholangitis, 10 cases of extrahepatic biliary obstruction, 20 cases of chronic viral hepatitis C, and 18 cases of histologically normal livers). Expression of fractalkine in biliary epithelial cells (BECs) in response to cytokine treatments was examined using a human cholangiocarcinoma cell line (HuCC-T1) and human intrahepatic BEC line. The chemotaxis of CX3CR1-expressing monocytes (THP-1) toward fractalkine was assayed using chemotaxis chambers. Fractalkine messenger RNA/protein were expressed on BECs of normal and diseased bile ducts, and their expression was upregulated in injured bile ducts of primary biliary cirrhosis. CX3CR1 was expressed on infiltrating mononuclear cells in portal tracts and on CD3(+), CD4(+), and CD8(+) intraepithelial lymphocytes of injured bile ducts in primary biliary cirrhosis. Fractalkine messenger RNA expression was upregulated in two cultured BECs on treatment with lipopolysaccharide and Th1-cytokines (interleukin 1beta, interferon gamma, and tumor necrosis factor alpha). THP-1 cells showed chemotaxis toward fractalkine secreted by cultured cells. In conclusion, Th1-cytokine predominance and lipopolysaccharide in the microenvironment of injured bile ducts resulting from primary biliary cirrhosis induce the upregulation of fractalkine expression in BECs, followed by the chemoattraction of CX3CR1-expressing mononuclear cells, including CD4(+) and CD8(+) T cells, and their adhesion to BECs and the accumulation of biliary intraepithelial lymphocytes.     

Plasma cells and the chronic nonsuppurative destructive cholangitis of primary biliary cirrhosis

There has been increased interest in the role of B cells in the pathogenesis of primary biliary cirrhosis (PBC). Although the vast majority of patients with this disease have anti-mitochondrial antibodies, there is no correlation of anti-mitochondrial antibody titer and/or presence with disease severity. Furthermore, in murine models of PBC, it has been suggested that depletion of B cells may exacerbate biliary pathology. To address this issue, we focused on a detailed phenotypic characterization of mononuclear cell infiltrates surrounding the intrahepatic bile ducts of patients with PBC, primary sclerosing cholangitis, autoimmune hepatitis, chronic hepatitis C, and graft-versus-host disease, including CD3, CD4, CD8, CD20, CD38, and immunoglobulin classes, as well as double immunohistochemical staining for CD38 and IgM. Interestingly, CD20 B lymphocytes, which are a precursor of plasma cells, were found in scattered locations or occasionally forming follicle-like aggregations but were not noted at the proximal location of chronic nonsuppurative destructive cholangitis. In contrast, there was a unique and distinct coronal arrangement of CD38 cells around the intrahepatic ducts in PBC but not controls; the majority of such cells were considered plasma cells based on their expression of intracellular immunoglobulins, including IgM and IgG, but not IgA. Patients with PBC who manifest this unique coronal arrangement were those with significantly higher titers of anti-mitochondrial antibodies. CONCLUSION: These data collectively suggest a role for plasma cells in the specific destruction of intrahepatic bile ducts in PBC and confirm the increasing interest in plasma cells and autoimmunity.     

Production of histological changes mimicking primary biliary cirrhosis in rabbits by immunization with bile duct antigen

Histopathological liver changes resembling primary biliary cirrhosis were induced in an experimental animal model. A special strain of rabbit received an antigen prepared from scrapings of bovine gallbladder mucosa. Eventually, 47 out of 84 antigen-treated rabbits displayed histopathological liver features resembling those of chronic non-suppurative destructive cholangitis as seen in humans. In addition, granuloma formation, ductular proliferation and fibrosis were seen in some cases. However, advanced lesions consistent with micronodular cirrhosis have not been found. Lymphocytes seemed to play an important role triggering early pathogenetic mechanisms, judging from the presence of lymphocytes invading the basement membrane of the affected bile ducts. Furthermore, we observed by electron microscopy that the epithelial cells of the involved bile ducts revealed both mitochondrial swelling and dilatation of endoplasmic reticulum cisternae. In summary, our experimental animal model offers interesting possibilities regarding the study of pathogenesis and development of primary biliary cirrhosis.     

Electron microscopic observation of destruction of biliary epithelium in primary biliary cirrhosis

ABSTRACT— Electron microscopic studies of the intrahepatic biliary tree in 16 patients with primary biliary cirrhosis (PBC) disclosed four types of biliary epithelial injury suggesting cell death in the ducts: 1) coagulative and 2) lytic necrosis without detachment of affected cells from the biliary epithelial layer, and 3) apoptosis and 4) detachment of several adjoining biliary cells from the basement membrane and neighboring biliary cells. Lesions 1), 2) and 3) were also found in livers with extrahepatic cholestasis without bile duct loss, and 1) and 2) were found in PBC livers irrespective of the degree of bile duct loss. 3) was rare and mostly confined to bile ductules, when present. By contrast, 4) was only observed in PBC, especially in livers with a moderate degree of bile duct loss in which extensive bile duct destruction appeared to be progressing. Detached biliary cells in lesion 4) were occasionally in contact with and/or surrounded by migrating lymphocytes with pseudopod formation, suggesting lymphocyte-target cell interactions. It therefore seems possible that epithelial detachment is an important ultrastructural lesion associated with extensive bile duct destruction in PBC livers.