Clinical, histologic, and immunopathologic features of primary biliary cirrhosis

Immunohistochemical analysis of cell-matrix adhesion molecules and their ligands in the portal tracts of primary biliary cirrhosis

Intraepithelial migration of lymphoid cells (epitheliotropism) through the basement membrane of the bile duct is a key event in the development of chronic non-suppurative destructive cholangitis (CNSDC) and eventual immune-mediated bile duct loss in primary biliary cirrhosis (PBC). Cell-to-cell and cell-to-extracellular matrix proteins may play an important role in the development of CNSDC. To address the events of epitheliotropism in CNSDC, the expression of cell-matrix adhesion molecules such as integrins alpha1, alpha3, alpha4, alpha5, and alpha6 and the distribution of fibronectin, laminin, and collagen type IV were studied immunohistochemically, with emphasis on both infiltrating lymphocytes and the bile ducts, in frozen sections from 15 PBC cases and 34 controls (chronic viral hepatitis, extrahepatic biliary obstruction, and normal liver). In PBC and chronic viral hepatitis, most of the infiltrating lymphoid cells expressed integrin alpha4, while such expression was less common in extrahepatic biliary obstruction and normal liver. A biliary basement membrane-like structure was delineated by immunostaining of collagen type IV and laminin in PBC and controls. On the basement membrane of CNSDC, fibronectin, a ligand of integrin alpha4, was strongly and frequently expressed in PBC, while such expression on the biliary basement membrane was rare in other controls. These results suggest that increased fibronectin expression on the biliary basement membrane and integrin alpha4-fibronectin interaction facilitate adhesion and the penetration of infiltrating alpha4-expressing lymphocytes into the biliary epithelial layer in PBC.

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.

A simple enzyme-linked immunosorbent assay for detection of anti-mitochondrial antibodies

An enzyme-linked immunosorbent assay (ELISA) has been developed for detection of anti-mitochondrial antibodies (AMA) in patients' sera. Results are expressed as a mitochondrial binding index, calculated from binding of patients' antibodies to rabbit liver mitochondrial fraction and total liver homogenate. The incidence of AMA detectable by this method in 22 sera from patients with primary biliary cirrhosis was identical with that obtained by conventional immunofluorescence testing (86%), and there was a highly significant correlation between titres determined by the two methods (r = 0.828; P less than 0.01) although ELISA titres were far higher. AMA were also detectable by ELISA in sera from 9/22 patients with chronic active hepatitis, 1/38 patients with other liver diseases, 3/16 patients with syphilis, 2/16 patients with non-hepatic autoimmune diseases and 0/29 normal blood donors; of these, only 2 chronic active hepatitis sera were positive for AMA by immunofluorescence. The ELISA titre was significantly correlated with the mitochondrial binding index determined at a serum dilution of 1:200 (r = 0.793; P less than 0.01), allowing an estimate of antibody titre to be made from ELISA screening at this single serum dilution. This assay, which is simple and reproducible, may be of value as an objective method of screening for AMA.

T-lymphocyte subsets in liver tissues of patients with primary biliary cirrhosis (PBC), patients with primary sclerosing cholangitis (PSC), and normal controls

T lymphocytes infiltrating hepatic tissues were typed and enumerated in liver biopsies of patients with primary biliary cirrhosis (PBC), patients with primary sclerosing cholangitis (PSC), and normal controls using monoclonal antibodies and the avidin-biotin-immunoperoxidase technique. The peripheral blood mononuclear cells were studied also by flow cytometry. In PBC, T lymphocytes were decreased (P less than 0.001) in the blood [absolute number was 426 +/- 200 (SE) vs 1351 +/- 416 in 15 controls], as was the helper/suppressor (T4/T8) ratio (1.0 +/- 0.1 vs normal 2.3 +/- 0.3). T lymphocytes were the most numerous mononuclear cells infiltrating portal areas of PBC livers: 749 +/- 93/5 high-power fields (HPF) in PBC vs 98 +/- 15/5 HPF (P less than 0.01) in controls. The T4/T8 ratios varied from 0.9 to 2.3 (mean, 1.8 +/- 0.1) in the portal triads (normal mean, 1.6 +/- 0.1), with the T4+ cells accounting for more than 75% of infiltrating T cells. In contrast, the mean T4/T8 ratio in portal triads of PSC was reduced (1.0 +/- 0.3) due to a significant increase (P less than 0.001) in the number of T8+ cells. The T cells around and in the walls of bile ducts in PBC were mostly T8+, and the T4/T8 ratio was 0.8 +/- 0.2. No T8+ cells were seen in this location in PSC and normal livers. Few mononuclear cells were present in hepatic lobules. Subtyping of T lymphocytes in liver tissues of patients with PBC and PSC may be helpful in the differential pathologic diagnosis. In patients with advanced PBC, a decrease in T4+ cells in the blood appeared to be accompanied by their accumulation in the portal triads. In contrast, T8+ cells accumulated preferentially around bile ducts.

Liver membrane antibodies detected by immunoradiometric assay in acute and chronic virus-induced and autoimmune liver disease

In this study, we describe a radioimmunoassay to detect liver membrane binding antibodies. The assay was designed to exclude binding of aggregated IgG or immune complexes to Fc gamma receptors of hepatocytes. When this assay was applied to sera from 142 patients, antibodies were found in highest titer in patients with autoimmune chronic active hepatitis, rarely in patients with hepatitis B virus-induced chronic active liver disease, and in 32% of patients with primary biliary cirrhosis. IgM antibodies were found in 100% of patients with acute Type A but not B or non-A, non-B hepatitis. IgA class antibodies were found in the sera of 57% of patients with alcohol-induced hepatitis. All patient groups showing significant titers of liver membrane antibodies display the lesion of piecemeal necrosis except those with alcohol-induced hepatitis. Further studies are needed to determine whether this antibody is the cause of the lesion.

Liver biopsy interpretation in hepatitis. Part II: Histopathology and classification of acute and chronic viral hepatitis/differential diagnosis

The morphological classification of acute and chronic viral hepatitis has been subject of considerable controversy. Main problems in nomenclature have arisen from the confusion of pathologically defined lesions with purely clinical designations. The classification used in this article is based on a number of recent reviews in which a certain measure of agreement has been reached between clinicians and histopathologists. As a general rule, in acute forms of hepatitis diffuse lobular changes predominate over portal lesions while chronic hepatitis is characterized by conspicuous alterations of portal (and periportal) areas. This report will merely summarize main diagnostic features of the different forms of viral hepatitis. For more detailed information the reader is referred to several leading articles discussing in detail morphology, and putting emphasis on pathogenesis. An exact "staging" of viral hepatitis by histologic criteria is an important tool in the evaluation of prognosis, indication and control of therapy as well as for comparison with immunologic findings.