Lymphocyte subsets studied with monoclonal antibodies in liver tissues of patients with alcoholic liver disease

Alcohol induces programmed death receptor-1 and programmed death-ligand-1 differentially in neuroimmune cells

Engagement of programmed death-1 (PD-1) receptor by its ligands (PD-L1/PD-L2) in activated immune cells is known to be involved in inflammatory neurological disease via a co-inhibitory signal pathway. Interaction of PD-1/PD-L1 is believed to occur only in activated neuroimmune cells because there are undetectable levels of PD-1/PD-L1 in normal physiological conditions. Here, we evaluated whether activation of neuroimmune cells such as human macrophage, brain endothelial cells (hBECs), astrocytes, microglia, and neurons by non-toxic concentrations of ethanol (EtOH) exposure can alter PD-1/PD-L1 expression. Thus, the present study is limited to the screening of PD-1/PD-L1 alterations in neuroimmune cells following ethanol exposure. We found that exposure of human macrophage or microglia to EtOH in primary culture immediately increased the levels of PD-L1 and gradually up-regulated PD-1 levels (beginning at 1-2 h). Similarly, ethanol exposure was able to induce PD-1/PD-L1 levels in hBECs and neuronal culture in a delayed process (occurring at 24 h). Astrocyte culture was the only cell type that showed endogenous levels of PD-1/PD-L1 that was decreased by EtOH exposure time-dependently. We concluded that ethanol (alcohol) mediated the induction of PD-1/PD-L1 differentially in neuroimmune cells. Taken together, our findings suggest that up-regulation of PD-1/PD-L1 by chronic alcohol use may dampen the innate immune response of neuroimmune cells, thereby contributing to neuroinflammation and neurodegeneration.

Increased immunogenicity to P815 cells modified with malondialdehyde and acetaldehyde

Aldehyde modified proteins have been associated with the development and/or progression of alcoholic liver disease (ALD). These protein adducts are capable of initiating many immunological responses that are harmful to the normal homeostasis of organism function. Previous studies have shown that malondialdehyde (MDA) and acetaldehyde (AA) synergistically form a unique adduct (MAA) with soluble proteins, which are capable of inducing cytokine release, T-cell proliferation, and antibody production. The purpose of this study was to determine whether MAA adduction can elicit similar responses to cells using a well-defined tumor model. The mouse mastocytoma P815 tumor cell line was modified with MAA (P815-MAA) or left unmodified (P815) and 10(6) irradiated cells were injected into DBA/2 mice once a week for 5 weeks. Serum was collected and tested for antibody responses to P815 cells and the MAA epitope. Immunization of MAA adducted P815 cells into syngeneic DBA/2 mice induced a strong antibody response to the MAA epitope as determined by ELISA on Alb and MAA-Alb (508 microg/ml and 1092 microg/ml, respectively). In addition, antibody to unmodified P815 cells was detected by fluorescent technique. Mice immunized with P815 cells or PBS showed little or no reactivity to the MAA epitope or P815 cells. Studies to assess IL-12 stimulation showed that peritoneal macrophages from P815 and PBS immunized animals produced modest amounts of IL-12 (20 and 35 pg/ml) when stimulated with Alb or MAA-Alb. However, macrophage from P815-MAA immunized mice responded to soluble MAA adduct (142 pg/ml). Finally, in tumor survival studies the mean survival was 14.25 days in PBS treated mice; 15.75 days with P815 immunized mice and 18.25 days with P815-MAA immunized mice. Therefore, these data strongly suggest that antibody responses are induced by P815 cells modified with MAA adducts. This may be a possible tool to begin looking at how alcohol metabolites potentially modify cells and/or cellular components making them recognizable to the immune system as foreign. It is thought that these studies define a model system that will be useful in assessing antibody and potentially T-cell responses to cells that are modified by MAA.

Sex differences and the effects of alcohol on immune response in male and female rats

Although it is clear that both alcohol and sex hormones impact immune function, very little information is available on the effects of alcohol on immune response in males versus females. We decided to determine if the alterations in immune response resulting from alcohol feeding might be expressed differently in males and females. To accomplish this we utilized pair-fed male and female Sprague-Dawley rats. Animals were fed a liquid diet for 60 days containing 30% of their calories as ethanol, and after 1 week this concentration was increased to 45% ethanol. Controls received liquid control diet of the same caloric and nutritional composition, and immune status was monitored with in vivo and in vitro techniques. Ethanol feeding significantly reduced the phytohemagglutinin skin response in males (p = 0.020) and females (p = 0.012). The concanavalin A blastogenic response of spleen cells prepared from female rats fed ethanol was significantly depressed with respect to spleen cells prepared from female rats fed the control diet (p = 0.0071). Alcohol also appeared to depress spleen cell blastogenic response in males, but this trend did not quite reach significance (p = 0.071). Spleen cells from groups of ethanol and control male and female rats were labeled with fluorescent monoclonal antibodies and run on a Fluorescent-Activated Cell Sorter. Ethanol significantly increased the percentage population of CD4 (T-helper cell) in males (p = 0.017), but not in females, and promoted an apparent, although nonsignificant, increase in the CD4/CD8 ratio in both sexes. An ELISA was used to measure IgM and IgG antibody elaborated by pokeweed mitogen-stimulated spleen cells in cultures.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell-mediated hepatic injury in alcoholic liver disease. Veterans Affairs Cooperative Study Group 275

BACKGROUND

The mechanism responsible for the initiation and perpetuation of alcoholic liver disease (ALD) remains poorly understood. This investigation attempted to elucidate the role of cell-mediated immune phenomena in the pathogenesis of ethanol-induced liver injury.

METHODS

Frozen liver biopsy specimens from 144 patients with moderate to severe ALD were examined by the avidin-biotin immunoperoxidase technique for the expression of antigenic markers of T and B lymphocytes, natural killer cells, and class I and II MHC molecules in the tissue.

RESULTS

Expression of CD3 by lymphocytes correlated significantly with regenerating nodules, intralobular inflammation, central sclerosis, and abnormalities of Kupffer cells. B cells were rarely present, and natural killer cells were absent. CD3+ lymphocytes expressed either CD4 or CD8 surface molecules. Enhanced class I MHC expression correlated significantly with portal inflammation, limiting plate erosion, vascular abnormalities, and hemosiderosis. Expression of class II MHC molecules correlated significantly with necrosis, bile stasis, and Mallory bodies.

CONCLUSIONS

The distribution and persistence of CD4+ and CD8+ cells in actively advancing ALD, the enhanced MHC expression on hepatocytes, and their relationship to alcoholic hyalin and necrosis lend support to the hypothesis that a cytotoxic T lymphocyte-hepatocyte interaction plays a role, perhaps via lymphokine production, in the genesis or perpetuation of ALD.

Quantitative immunohistochemical analysis of lymphocyte subsets in alcoholic liver disease

To investigate the role of lymphocytes frequently observed in the parenchyma of alcoholic liver disease (ALD), lymphocytes infiltrating into the liver were stained immunohistochemically with monoclonal antibodies (MoAb) and were quantitatively assessed by a morphometric analysis in 17 patients with ALD and, for comparison in five patients with chronic active hepatitis B (B-CAH). In patients with alcoholic hepatitis, the number of CD8+ lymphocytes in the hepatic lobule was similar to that in patients with B-CAH but was significantly greater than that in alcoholics with hepatic fibrosis (HF). The CD4/CD8 ratio in the hepatic lobule was low in both alcoholic hepatitis and B-CAH compared with that of alcoholic patients with HF. When Mallory bodies (MB) and lymphocytes were simultaneously stained with a specific antibody against MB and MoAb, respectively, only CD3+ and CD8+ lymphocytes were found to have a close contact with MB. These results suggest that in alcoholic hepatitis, hepatocyte necrosis may be partly mediated by immunological mechanisms involving cytotoxic T cells infiltrating into the hepatic lobule.

Immunohistochemical features of the portal tract mononuclear cell infiltrate in chronic aggressive hepatitis

The portal tract mononuclear cell infiltrate has been characterised in 28 liver biopsy samples showing features of chronic aggressive hepatitis from 12 patients with autoimmune chronic active hepatitis, 12 with primary sclerosing cholangitis, and four with other chronic liver diseases (two with alpha 1-antitrypsin deficiency, one with Wilson's disease, and one with chronic hepatitis B infection). In all patients liver disease had started in childhood. The mononuclear cell infiltrate was investigated by a two step immunoperoxidase technique using monoclonal antibodies to: total, alpha/beta T cell receptor positive, helper/inducer, suppressor/cytotoxic T lymphocytes; B lymphocytes; killer/natural killer cells; monocyte/macrophages; and to the activation markers HLA-DR antigens, interleukin 2 receptor (IL-2R), transferrin receptor, and 4F2Ag. In all samples the infiltrate consisted of mainly alpha/beta T cell receptor T lymphocytes. Although T helper/inducer cells predominated in patients with autoimmune chronic active hepatitis, T suppressor/cytotoxic lymphocytes were preponderant in patients with primary sclerosing cholangitis and the other chronic liver diseases. Killer/natural killer cells accounted for up to 25% of the mononuclear cell infiltrate in patients with autoimmune chronic active hepatitis, being rare or absent in the other diseases. Monocytes/macrophages were always found, but they were more numerous in primary sclerosing cholangitis than in the other chronic liver diseases. B lymphocytes were rare or absent in all subjects. Activated mononuclear cells were present in all subjects, but although in patients with autoimmune chronic active hepatitis and primary sclerosing cholangitis most cells of the infiltrate expressed HLA-DR antigens and up to 75% IL-2R, in other forms of chronic liver diseases HLA-DR positive cells were less common and IL-2R positive cells ere rare or absent. These results show that the cells responsible for the histological characteristics of chronic aggressive hepatitis vary in their functional phenotype and state of activation according to the type of underlying liver disorder, confirming the involvement of different pathogenetic mechanisms.

Nitric oxide production by monocytes in alcoholic liver disease

Nitric oxide, initially described as an endothelial-derived relaxing factor, has recently been recognised as a mediator of macrophage function. We have studied the production of nitric oxide by peripheral blood monocytes from both normal volunteers and alcoholics. This was measured indirectly by assessing nitrite formation. Normal monocytes were found to produce a basal level of nitrite, which could be stimulated more than 6-fold using endotoxin. This effect was abrogated by the addition of nitric oxide synthesis inhibitor, L-n-monomethyl-arginine. A striking difference was observed in the monocytes obtained from alcoholics with and without evidence of alcoholic hepatitis. Whereas the latter behaved in a similar manner to the controls, the former had markedly increased basal levels. In the hepatitis group there was also substantial inhibition of production by L-n-monomethyl-arginine. We believe that these results indicate that nitric oxide derived from monocytes may play a role in the pathogenesis of alcoholic liver disease, especially alcoholic hepatitis.

Bronchoalveolar lavage in alcoholic liver cirrhosis. T-lymphocyte subsets and immunoglobulin concentrations

The purpose of this study was to determine the phenotype profiles of immune effector cells and the concentrations of immunoglobulins in the lower respiratory tract of non-smoking patients with alcoholic liver cirrhosis (ALC). Nine nonsmoking patients with liver biopsy-proved ALC (grade B or C cirrhosis in Child's classification), free of clinical pulmonary symptoms, and with normal chest roentgenogram were included in the study. The control group included 12 healthy nonsmokers. Each patient had fiberoptic bronchoscopy with bronchoalveolar lavage (BAL). The number of T cells and of lymphocyte subpopulations was determined by immunofluorescence studies using monoclonal antibodies that were specific for CD3, CD4, and CD8 markers. Patients with ALC exhibited a dramatically increased percentage of CD8+ cells in BAL that induced a low CD4/CD8 ratio (0.96 +/- 0.15 vs 1.8 +/- 0.12 in healthy controls). Further characterization of lymphocyte subsets' dual immunofluorescence analysis demonstrated that most of the CD8+ alveolar lymphocytes had a phenotype of cytotoxic cells (CD8+ CD11b-; 48 percent +/- 13 in ALC vs 10 percent +/- 5 in controls). ALC was associated with an appreciable alveolar-capillary "leak" as demonstrated by a significant increase in BAL fluid albumin. In addition, the concentrations of immunoglobulins in BAL fluid were significantly greater in ALC than in controls. However, the relative (to albumin) coefficient of excretion of IgG, A, and M in and alpha 2-macroglobulin BAL fluid was not significantly different between controls and ALC. Our results indicate that increased proportions of CB8+ and especially of CD8+ CD11b- cells are a common feature in the lower respiratory tract of nonsmoking patients with ALC. These changes may be of potential functional importance in the regulation of the local pulmonary immune response in ALC.

Activated CD-8 cells and HLA DR expression in alcoholics without overt liver disease

Lymphocytes from alcoholics without liver disease were immunophenotyped by flow cytometry immediately after admission for detoxication and again after 4 to 10 days of abstinence. We found a small but significant elevation of T lymphocytes at admission compared to controls and decreases in the numbers of B cells and natural killer cells in many patients. A significant elevation of activated T cells was confirmed. The ratio of activated T cells to activated non-T cells was also substantially increased, but declined slightly during early withdrawal. The increase in activated T cells was due mostly to increased numbers of activated CD8hi cells. These activation changes did not revert toward normal as quickly as the other changes and may represent an indication of immune damage at a preclinical stage. An additional finding of interest was a substantial decrease in the expression of HLA DR on CD4+ and non-T cells. The significance of this decrease is not known, but we speculate that it may result in a decline in the efficiency of antigen presentation.

Lymphocytes from hepatic inflammatory infiltrate kill rat hepatocytes in primary culture. Comparison with peripheral blood lymphocytes

In the last few years it has become possible in the liver to isolate lymphocytes from inflammatory infiltrates and to culture them in vitro. Most of the lymphocyte clones obtained are CD 8+ cytotoxic cells, but interactions between these lymphocytes and hepatocytes in primary culture have not been analysed previously. In this study, cloned human T lymphocytes from liver biopsies and from the peripheral blood of patients with chronic hepatitis B or primary biliary cirrhosis, after phenotypical and functional characterization into CD 8+ or CD 4+ cytotoxic lymphocytes, were activated in an antigen-independent fashion by adding either anti CD 3 or anti CD 2/R-3 monoclonal antibodies to the cell suspension. The activated cells were then coincubated with rat hepatocytes in primary culture. The killing capacity of the activated lymphocytes was monitored by light and electron microscopy and by measurement of lactic dehydrogenase (LDH)-release into the culture medium. It was found that cytotoxic CD 8+, but not CD 4+ helper lymphocytes very effectively killed hepatocytes. The killing effect was dependent on the time of cocultivation and on effector-target (E/T) ratio. Total breakdown of the hepatocyte monolayer was achieved after 10-20 h coculture and at an E/T ratio of 10 to 1. As LDH-release in the culture medium reached about 80% of the total LDH-content, most of the hepatocytes were lysed by activated lymphocytes. Cytotoxic activity of clones obtained from different biopsies was comparable with that of clones from peripheral blood. Hepatocytes in primary culture seem to be very sensitive to the killing capacity of activated cytotoxic lymphocytes.

Functional and numerical alterations induced by ethanol in the cellular immune system

Ethanol was found to alter functioning and numbers of lymphoid cells of the cellular immune system in humans and rats. In in-vitro studies on human lymphocytes, a higher than 0.1% concentration of ethanol and acetaldehyde and acetic acid, the metabolites of ethanol, caused a decrease in the formation of E-rosettes. Methanol and propanol also resulted in a decrease in E-rosette formation. The natural killer (NK) cells varied in their ability to lyse tumor cells. In vitro, the NK-cell activity declined at higher than 0.2% concentration of ethanol. The NK activity in cells isolated from spleen and thymus of rats fed 1 g/dl or 7 g/dl ethanol did not differ significantly from the controls. Sprague Dawley rats fed 1 g/dl or 7 g/dl ethanol for 12 weeks had a significantly smaller thymus compared to the controls. Alveolar macrophages isolated from the rats exhibited impaired phagocytic activity. In agreement with other investigators, ethanol was found to result in a loss of T-cell population in the spleens of rats fed ethanol for 13 months. On the other hand, the T-helper cells and the proportion of T-helper to T-suppressor cells were found to increase in the splenocytes from these rats. This latter occurrence, apparently, is to compensate for the general loss of T-cell population observed in the body that occurs with ethanol ingestion. It is hypothesized that immunosuppression and the transient imbalances in the components of the cellular immunity induced by ethanol lead to an increased risk of pathogenesis associated with alcohol consumption.

Alcohol and immune regulation. I. In vivo effects of ethanol on concanavalin A sensitive thymic lymphocyte function

Alcohol is known to suppress the immune response, but the underlying mechanism to account for this immune suppression is still not clearly elucidated. In an attempt to clarify such mechanisms, experimental rats were fed for 50 days on a 36% ethanol, Lieber diet (LED) while control (LCD) rats were fed a similar diet supplying the same amount of calories but lacking ethanol. It was found that both LCD and LED animals grew at a linear rate (LCD: r = 0.981, LED: r = 0.961) but that LCD animals grew more rapidly. While thymic weights in the LED group were significantly smaller (P less than 0.05) than in the LCD group, the ratios of thymic weight/body weight between these groups were not significantly different. To identify the effects of ethanol on immune response, thymic (Th) or splenic (S) cells were prepared and incubated in culture with the mitogen, Con A and rat serum prepared from LCD or LED groups. It was found that lymphocytes prepared from thymus of LED animals appeared to be depressed in mitogen-driven blastogenic transformation when incubated in LCD serum but not LED serum. Furthermore, lymphocytes prepared from the spleen of LED animals appeared to be depressed in mitogen driven blastogenic transformation when incubated in LED serum but not LCD serum. Since lymphocytes of the thymus and spleen are undergoing maturation and replication this implies that ethanol may alter these processes.

Immunoelectron microscopic observations on the inflammatory infiltrates and HLA antigens in hepatitis B and non-A, non-B

The present knowledge of the inflammatory reaction occurring in situ during hepatitis B favors a T cell-dependent MHC-restricted immune response. However, the reports in the literature are primarily based on the application of monoclonal antibodies directed at different lymphocyte subsets which discern only lymphocytic phenotypes and do not reflect the actual situation adequately. Therefore, we investigated the liver biopsies of patients with hepatitis B (28 patients) and non-A, non-B (21 patients) by immunoelectron microscopy with monoclonal antibodies directed at lymphocyte subtypes (pan-B, pan-T, T8, T4 and NKH1) and at activation epitopes (IL-2 receptor, TA1 and T11/3) as well, in order to determine the phenotype in association with the activation status of the lymphocytes that are in close contact with hepatocytes; thus, establishing an effector-target cell relationship on the ultrastructural level. We were able to confirm the central role of T8 lymphocytes being the predominant type of lymphocytes in close contact with liver cells in the space of Disse. A certain percentage of these cells expressed "activation" markers as IL-2 receptor, TA1 and T11/3. In acute hepatitis, the NK lymphocytes made up a fifth of all lymphocytes, whereas their number dropped below 10% in the chronic stage. There was a vague correlation between the inflammatory activity of the disease and the expression of HLA antigens (both classes I and II) on inflammatory cells and also on hepatocytes. The results did not show significant differences between hepatitis B and non-A, non-B.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Studies of lymphocyte subpopulations in the liver tissue and blood of patients with chronic active hepatitis (CAH)

Monoclonal antibodies to antigens on the surfaces of mononuclear cells (MNC) were used to characterize lymphocyte subpopulations infiltrating portal areas and parenchyma of livers in 31 patients with chronic active hepatitis (CAH). The distribution and numbers of infiltrating lymphocytes were determined in serial sections immunostained by the avidin-biotin-peroxidase complex method. T lymphocytes were the major component of inflammatory cells in the portal tracts. In the peripheral blood and portal areas, T helper-inducer (T4+) cells were the more numerous subpopulation. However, the hepatic lobules and areas of "piecemeal" necrosis always contained more T suppressor-cytotoxic (T8+) cells. The latter were demonstrated in contact with HBsAg-containing hepatocytes in tissues of patients with HBsAg-positive CAH. The mean numbers of T lymphocytes infiltrating the portal and periportal areas of livers from patients with HBsAg-negative and HBsAg-positive CAH were not different. Large numbers of B cells forming distinct follicles were seen in tissues from patients with HBsAg-positive CAH. The presence of increased numbers of portal T and B lymphocytes correlated with progressive liver damage as observed in two patients studied at yearly intervals.