Immunohistochemical analysis of HLA (A, B, C) antigens in liver disease using a monoclonal antibody

Hepatocellular expression of a novel glycoprotein with sialylated difucosyl Lex activity in the active inflammatory lesions of chronic liver disease

Hepatic expression of sialylated difucosyl Lex antigen (SDLex, NeuAc alpha 2-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-) was studied with monoclonal antibody FH6, which defines this structure. Hepatocytes in the severe form of chronic active hepatitis and liver cirrhosis strongly expressed SDLex. The antigen was only weakly and focally detected in chronic persistent hepatitis. The mild form of chronic active hepatitis showed intermediate expression. SDLex expressed along the liver cell membranes displayed a honeycomb pattern when extensively expressed in the severe form of chronic active hepatitis or in liver cirrhosis. Cytoplasmic expression was faint and focal. Preferential tissue distribution was at the periphery of the hepatic lobules where the distruction of the limiting plate was present. The antigen was also expressed in sinusoidal lining cells and polymorphonuclear cells but not in the biliary epithelia. Hepatocytes expressing SDLex did not express related carbohydrate antigens, ie, Type 2 chain N-acetyllactosamine, Lex, and sialylated Lea. On subcellular fractionation, the microsome fraction contained the majority of the antigen activity. SDS-PAGE and Western blot analysis revealed one major SDLex-active glycoprotein with an apparent molecular weight of 110 kilodaltons. This glycoprotein was different from SDLex-active glycoproteins found in the sera of cancer patients. No ganglioside showed FH6 reactivity. These results indicate that liver cells in active inflammatory lesion expressed a novel glycoprotein carrying SDLex antigen in honeycomblike membrane-associated pattern.

HLA-A,B,C, HLA-D/DR and HLA-D/DQ expression on unfixed liver biopsy sections from patients with chronic liver disease

The distribution of HLA-A,B,C, HLA-D/DR and HLA-D/DQ molecules was studied by indirect immunofluorescence with an avidin-biotin technique and monoclonal antibodies, in unfixed cryostat sections of liver biopsies from 76 patients with chronic liver diseases of various aetiologies and five normal liver biopsy specimens. In pathological liver, strong cytoplasmic or membrane-like positivity for HLA-A,B,C of hepatocytes was observed in piecemeal necrosis areas in all groups. Cytoplasmic staining was mainly seen in lobular areas in autoimmune, cryptogenic and HBV-related cases with viral replication, while membrane-like positivity was more frequently observed in primary biliary cirrhosis, alcoholic and HBV-related cases without viral replication. A weak cytoplasmic staining for HLA-D/DR was observed in piecemeal necrosis and lobular areas mainly in HBV-related cases with viral replication. While bile duct cells were positive for both HLA-D/DR and HLA-D/DQ, hepatocytes were consistently HLA-D/DQ negative. The increased HLA-A,B,C expression on hepatocytes should allow T cytotoxic cell aggression. Hepatocellular HLA-D/DR expression is definite but weak and probably does not allow direct autoantigen presentation and induction of autoimmunity. Negativity for HLA-D/DQ further supports this hypothesis. Since cytoplasmic staining for Class I and II molecules is greatly lowered by fixing cryostat liver sections, prestaining conditions should be taken into account when comparing different studies.

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.

Immunohistochemical study of HLA class 1 antigens on the hepatocytes of patients with chronic hepatitis B

In order to evaluate the role of histocompatibility antigen (HLA) class 1 antigens in the pathogenesis of liver cell necrosis, HLA class 1 antigens on hepatocytes were studied in the liver biopsy materials from 20 patients with chronic hepatitis B by the peroxidase-labeled antibody method using a monoclonal antibody to human HLA-A, B, C (Cappel Laboratories). Both increased expression of HLA class 1 antigens on the hepatocytes and decreased distribution of intrahepatic hepatitis B core antigen (HBcAg) were observed in patients with an exacerbation of the inflammatory activity. These findings suggest that expression of HLA class 1 antigens on the hepatocytes may be increased when an exacerbation of inflammatory activity develops, and may be compatible with the concept that expression of these antigens plays and important role for the lysis of hepatitis B virus (HBV)-infected liver cells by cytotoxic T cells. Furthermore, in seven patients, expression of HLA class 1 antigens was studied in the liver before and after treatment with human lymphoblast interferon (IFN)-alpha, recombinant IFN-alpha or IFN-beta. Increased expression of HLA class 1 antigens was observed in patients with decreased intrahepatic HBcAg and DNA-P in sera after IFN treatment. These results also suggest that the increase of HLA class 1 antigens by IFN may be related to the immune mechanism for the effective elimination of HBV.

Disorganisation of intermediate filament structure in alcoholic and other liver diseases

The distribution of Mallory body antigens JMB1 and 2 was examined in 82 human fresh diagnostic needle liver biopsies and 28 necropsies by the indirect immunoperoxidase technique using 2 monoclonal antibodies (anti-JMB1 and 2) against Mallory bodies. The JMB1 antigen was detectable in bile duct epithelium and in hepatocytes of histologically normal livers. It was also found in all Mallory bodies in various hepatic disorders. This antigen was markedly increased in the cytoplasm of all liver cells in acute alcoholic hepatitis superimposed on alcoholic cirrhosis, in most cases of acute alcoholic hepatitis, and in severe fatty infiltration of the liver with or without Mallory body formation. Mallory bodies contained this antigen but the cytoplasm of Mallory body containing cells lacked JMB1. In normal liver the JMB2 antigen was localised on the cytoplasmic intermediate filament network of hepatocytes and bile duct epithelium; and almost all Mallory bodies also contained this antigen but the adjacent cytoplasm of these cells lacked JMB2. In severe alcoholic liver disease these antigens could not be detected in large zones of hepatocytes even when these hepatocytes did not contain Mallory bodies. It is evident that there is disorganisation of intermediate filament constituents in severe alcoholic liver disease.

Expression of HLA class I antigens on hepatocytes in liver disease

Recent studies have demonstrated aberrant expression and topographical heterogeneity of HLA Class I and Class II antigens in tissues of patients with certain immunologic or neoplastic diseases. Current information about the expression of HLA antigens by normal and diseased hepatocytes is controversial. We analyzed the HLA antigenic profile of 4 normal fetal livers, 5 normal adult livers, 7 cases of chronic hepatitis B virus (HBV) infection, 14 cases of cirrhosis of various etiologies, 11 hepatic neoplasms, and 5 continuous cell lines derived from hepatic tumors. The specimens were tested by the indirect fluorescent antibody method with a panel of monoclonal antibodies to distinct monomorphic determinants of HLA Class I and Class II antigens and to beta 2-microglobulin. HLA Cells I antigens were not detected on normal fetal and adult hepatocytes, but were displayed on the plasma membrane of hepatocytes in the majority of all hepatic diseases tested and of the 5 hepatic tumor cell lines. There was a significant correlation between the expression of HLA Class I antigens on hepatocytes and the intensity of intralobular inflammation. Double immunofluorescent staining of livers infected with hepatitis B virus demonstrated simultaneous expression of HLA Class I antigens and HBsAg or HBcAg only in a small percentage of hepatocytes, suggesting lack of a specific association between HLA Class I and these viral antigens. HLA Class II antigens were not detected on hepatocytes from any of the liver diseases tested but were expressed by one of the 5 liver carcinoma cell lines analyzed. These findings confirm that HLA Class I antigens are not detectable within the limits of several immunohistochemical methods on normal hepatocytes and suggest that injury by a variety of factors directly or indirectly leads to induction of these antigens on the plasma membrane of hepatocytes.

PLP fixation for combined routine histology and immunocytochemistry of liver biopsies

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Cell-mediated immunity in liver disease

Four liver diseases in which cell-mediated immunity seems to be of major importance but in which the exact pathogenic event has been not fully clarified have been briefly discussed. More precise delineation of the phenotypes of mononuclear cells and the advent of in vitro techniques for the study of lymphocyte function and cytotoxicity have led to better understanding of the importance of cell-mediated immunity in some liver diseases. It seems that the liver itself may be variously affected by different immunologic reactions, not only in various diseases but also in different locations in the same disease.

Expression of beta 2-microglobulin on hepatocytes in acute and chronic type B hepatitis

beta 2-Microglobulin display was examined in 131 liver biopsies from patients with acute and chronic type B hepatitis, using an indirect immunoperoxidase method. Enhanced expression of beta 2-microglobulin on hepatocyte membranes was observed in patients with acute hepatitis, chronic active hepatitis with moderate to severe activity and cirrhosis, when compared with normal liver. In acute hepatitis, beta 2-microglobulin-positive hepatocytes were mainly observed in perivenular areas in association with bridging necrosis. In chronic hepatitis, beta 2-microglobulin-positive hepatocytes were observed mainly in periportal zones and in some areas of lobular activity. Diffuse-enhanced display of beta 2-microglobulin on hepatocytes was observed in 5 of 6 patients treated with lymphoblastoid interferon as part of a trial of antiviral therapy. The mechanism by which beta 2-microglobulin display is enhanced on hepatocytes in patients not treated with interferon is uncertain. However, display of beta 2-microglobulin on hepatocytes probably reflects display of HLA-A, B and C antigens and may influence the course of hepatitis B virus infection by increasing susceptibility of the affected cells to T cell-mediated immune attack.

Hepatic beta 2-microglobulin distribution in primary biliary cirrhosis

The distribution of beta 2-microglobulin (beta 2-m) was studied by immunoperoxidase in paraffin sections of 30 liver biopsies from 28 patients with primary biliary cirrhosis (PBC). In 24 of the patients beta 2-m was demonstrable on the membranes of hepatocytes, whereas normal hepatocytes were usually negative. This increased display of beta 2-m probably parallels increased display of class I HLA antigens. The affected hepatocytes may be more susceptible to T cell-mediated immune attack. A greater number of beta 2-m displaying hepatocytes was seen in the later stages of PBC, in keeping with the hypothesis that in this disease hepatocyte involvement is a secondary phenomenon. Bile duct epithelium continued to display beta 2-m at all stages of the disease.

Ultrastructural immunocytochemical demonstration of HLA class I antigens in human pathological liver tissue

Major histocompatibility complex products Class I (HLA Class I) antigens are not expressed on the surface of normal human hepatocytes but become so in pathological conditions. The purpose of this study was to specify the ultrastructural topography of HLA Class I antigens expression. Nine human liver specimens, known from light microscopic investigation to display membranous positivity for HLA Class I antigens, were processed for immunoelectronmicroscopy using monoclonal anti-HLA Class I in an indirect immunoperoxidase procedure. HLA Class I antigens were detected on the basolateral membrane of hepatocytes and bile duct cells; some cisternae of the endoplasmic reticulum were also positive. The membranes of normal bile canaliculi of hepatocytes and the apical border of bile duct cells were negative. In one case of presumably drug-induced cholestasis, abnormal cholestatic canaliculi displayed HLA Class I antigens. These results indicate that HLA Class I antigens are synthesized by the hepatocytes and bile duct cells and incorporated into the plasma membrane; the basolateral expression follows the pattern as in other polarized cells. The expression in cholestatic canaliculi suggests a disturbed polarity of the hepatocyte.

Expression of beta-2-microglobulin on hepatocytes after liver transplantation

The distribution of beta 2-microglobulin was studied by an immunoperoxidase method in paraffin sections from sixteen serial graft liver biopsy samples taken after liver transplantation from four patients who had received transplants for advanced primary biliary cirrhosis. Mild to moderate acute rejection was diagnosed in three of the patients. Expression of beta 2-microglobulin on hepatocyte membranes was greater during rejection, and tended to fall after the rejection episode. However, a few hepatocytes continued to display beta 2-microglobulin on their cell membranes. Rejection was characterised histologically by infiltration of portal tracts with lymphoid cells, and cholestasis. Enhanced display of beta 2-microglobulin on hepatocytes probably reflects display of HLA A, B, and C antigens and may be associated with increased susceptibility of the affected cells to T-lymphocyte-mediated immune attack.

Aberrant expression of HLA-DR antigens on bileduct epithelium in primary biliary cirrhosis: relevance to pathogenesis

Direct immunofluorescence with an avidinbiotin system was used to investigate the expression of MHC molecules HLA-DR and HLA-A,B,C on bileducts in cryostat sections from 10 primary biliary cirrhosis (PBC) patients. Needle biopsy specimens from 55 patients with various chronic liver disorders, surgical biopsy specimens from 2 patients with recurrent secondary cholangitis, and 4 normal livers were used as controls. Normal bileducts did not express DR whereas in 8/10 PBC biopsy specimens there were varying degrees of cytoplasmic DR staining in septal or interlobular bileduct epithelium. In the early histological stages of PBC the aberrant DR expression was multifocal, but in late-stage specimens whatever ducts remained were all positive. This pattern resembles that in focal thyroiditis and suggests that DR expression is an early manifestation of autoimmune cholangitis. In 6/61 control biopsies only weak staining was detected in occasional small interlobular ducts. The class I HLA-A,B,C expression normally seen on biliary epithelium was increased in 8/10 PBC cases and in 19/61 non-PBC biopsies. Perhaps the aberrant expression of HLA-DR antigens on bileduct epithelium in PBC enables these cells to present "self antigens" to sensitised T-lymphocytes and to promote autorecognition, possibly in response to several environmental triggers; the increased HLA-A,B,C, expression may be a means of amplifying T-cell cytotoxic responses.