Liver membrane antibodies in alcoholic liver disease: 1. prevalence and immunoglobulin class

Autoantibodies and immunoglobulins in alcoholic steatosis and cirrhosis

Antinuclear antibodies were significantly more prevalent (p less than 0.01) in 143 patients with alcoholic cirrhosis than in 64 patients with alcoholic steatosis and in 94 controls. Smooth muscle antibodies were significantly more prevalent (p less than 0.05) in patients with alcoholic steatosis and cirrhosis than in controls. The prevalence of antimitochondrial antibodies and IgG liver membrane antibodies did not differ significantly between the three groups. Immunoglobulin G, A, and M concentrations were only occasionally increased in patients with steatosis. Patients with cirrhosis had significantly increased (p less than 0.005) concentrations of immunoglobulins G, A, and M when compared to patients with steatosis. These results indicate that the degree of liver damage has more effect than chronic alcoholism on the humoral immune system. Whether this influence is direct or indirect remains to be established.

Treatment of alcoholic hepatitis

Cirrhosis and its sequelae are responsible for close to 2% of all causes of death in the United States. Some studies have suggested that the costs of liver disease may account for as much as 1% of all health care spending, with alcohol-related liver disease (ALD) representing a major portion. It accounts for between 40% to 50% of all deaths due to cirrhosis, with an accompanying rate of progression of up to 60% in patients with pure alcoholic fatty liver over 10 years, and a 5-year survival rate as low as 35% if patients continue to drink. A subset of patients with ALD will develop an acute, virulent form of injury, acute alcoholic hepatitis, which has a substantially worse prognosis. Despite enormous progress in understanding the physiology of this disease, much remains unknown, and therefore, a consensus regarding effective therapy for ALD is lacking. Conventional therapy is still based largely on abstinence from alcohol, as well as general supportive and symptomatic care. Unfortunately, hepatocellular damage may progress despite these measures. Multiple treatment interventions for both the short- and long-term morbidity and mortality of this disease have been proposed, but strong disagreement exists among experts regarding the value of any of the proposed specific therapeutic interventions.

IgA against gut-derived endotoxins: does it contribute to suppression of hepatic inflammation in alcohol-induced liver disease?

Endotoxins of intestinal origin are supposed to play an important role in the development of alcoholic hepatitis in man. To estimate the role of immunoglobulin response to gut-derived endotoxin in the development of alcohol-induced liver disease, serum levels of IgA and IgG against fecal endotoxin, endotoxin, and acute-phase proteins were measured in patients with different stages of alcoholic liver disease and in healthy controls. Antibodies of type IgA, but not IgG, against fecal endotoxins were significantly increased in patients with alcohol-induced liver disease. IgA antibodies against fecal endotoxin were found to be closely correlated with the plasma concentrations of alanine aminotransferase, gamma-glutamyl transferase, and C-reactive protein in patients with alcoholic liver disease. In conclusion, as IgA located in body tissue was shown to suppress the inflammatory process, enhanced production of IgA against endotoxin of intestinal origin may contribute to inactivation of this compound, thereby reducing its damaging effect on the liver.

Autoantibodies in alcoholic liver disease

Despite many decades of research, the reasons why only a relatively small proportion of individuals who consume excessive quantities of alcohol develop clinically significant liver disease remain unknown. The association with features of autoimmune diseases, including hypergammaglobulinaemia, circulating autoantibodies, inheritance of certain immunogenetic (HLA) markers and response to corticosteroid therapy in some patients has led to a persistent impression that altered immune regulation with a relative loss of self-tolerance underlies susceptibility to the development of the more severe forms of alcoholic liver disease (alcoholic hepatitis and/or cirrhosis). However, review of the data from the numerous studies that have been conducted over the past 30 years fails to reveal sufficiently convincing evidence that autoimmunity plays a primary role in alcohol-related liver damage. In particular, most of the wide range of circulating autoantibodies that have been reported in patients are found mainly at low titres, are not confined to those with severe liver injury, and are probably more likely to be a response to the hepatic insult than causally related to liver damage. Additionally, an association with various HLA phenotypes has not been confirmed by meta-analysis. Interpretation is complicated by evidence that alcohol may have direct effects on some components of the immune system but, if there is an immunogenetic basis for alcoholic liver disease, the present evidence suggests that this might be related more to cytokine gene polymorphisms than to a predisposition to autoimmunity per se.

Serum IgA antibodies to human gut luminal aspirates and human liver in alcoholic liver disease

BACKGROUND

Elevation of serum IgA is a characteristic feature of alcoholic liver disease. It has been proposed that this occurs partly as an antigenic response to gut-derived proteins or acetaldehyde-modified liver proteins, but the principal antigens responsible remain unknown.

AIMS

The goal of this study was to determine if serum IgA antibodies were present against human gut luminal antigens or liver antigens in alcoholic liver disease.

PATIENTS AND METHODS

Twenty-nine patients with alcoholic liver disease, 10 with primary biliary cirrhosis, 12 with "other" liver diseases, 8 alcoholics, and 20 healthy subjects were studied. Western blotting was used to examine the reactivity of sera from these groups against human small and large bowel aspirates and liver tissue from alcoholic liver disease patients.

RESULTS

Serum IgA antibodies to a 140 kDa colonic luminal protein were found in 22 (76%) patients in the alcoholic liver disease group (p < 0.0001), and 7 (24%) patients had serum IgA antibodies to a 40 kDa colonic luminal protein (p = 0.04). These responses were confined to colonic aspirates and not observed in other disease groups, alcoholics or healthy subjects. There was no significant serum IgA response to human liver proteins in alcoholic liver disease.

CONCLUSIONS

Serum IgA antibodies to a human 140 kDa colonic luminal protein are frequently found in alcoholic liver disease. This novel antigen may contribute to the increased levels of circulating IgA in alcoholic liver disease.

Social drinking and the immune response: impairment of lymphokine-activated killer activity

The effect of limited and intermittent alcohol ingestion on the immune response in humans has not been extensively studied. The authors, in this study, evaluate peripheral blood mononuclear cell cytotoxicity before and after alcohol ingestion in a setting designed to mimic social drinking. Eleven healthy volunteers consumed two 12 oz (355 mL) cans of beer in 30 minutes while eating pizza. Five control individuals ingested non-alcoholic beverages. Natural killer and lymphokine-activated killer activity were determined for peripheral blood mononuclear cells obtained before and 30 minutes after alcohol ingestion. Interleukin 2-induced lymphokine-activated killer activity was significantly reduced in blood samples obtained after alcohol ingestion when compared with pre-alcohol samples (p < 0.01). Natural killer activity (unstimulated) was not affected by alcohol ingestion. The authors demonstrate that ingestion of a small amount of alcohol impairs the cytotoxic capacity of peripheral blood mononuclear cells. Alcohol in the context of social drinking may have deleterious effects on the immune system's ability to clear virus-infected cells or cells that have undergone neoplastic transformation, especially for individuals with pre-existing immunosuppression.

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.

Immunoglobulin A antibody to a 200-kilodalton cytosolic acetaldehyde adduct in alcoholic hepatitis

Considerable clinical and experimental evidence points to the importance of immune responses in the development of alcoholic liver disease. In the present study it was investigated whether circulating antibodies from patients with alcoholic liver disease recognize acetaldehyde-liver protein adducts. Cytosolic and microsomal fractions from livers of Wistar rats or from normal human liver were incubated with acetaldehyde (0.5-2.5 mmol/L) and/or cyanoborohydride (100 mmol/L) then analysed by immunoblotting. Cytosolic fractions that had been incubated with acetaldehyde and cyanoborohydride expressed a 200-kilodalton protein antigen not present in untreated fractions or fractions incubated with acetaldehyde or cyanoborohydride alone. The 200-kilodalton antigen was recognized by immunoglobulin (Ig)A antibodies in a large proportion of sera from patients with alcoholic hepatitis (70%, n = 23), but in significantly smaller proportions of sera from patients with alcoholic cirrhosis without hepatitis (30%, n = 10; P < 0.05), heavy drinkers without overt liver disease (20%, n = 10; P < 0.02), patients with nonalcoholic liver disease (35%, n = 17; P < 0.05), or normal control subjects consuming moderate quantities of alcohol (25%, n = 20%; P < 0.005). These results indicate that IgA antibodies to a 200-kilodalton acetaldehyde-protein adduct are present in a large proportion of patients with alcoholic liver disease and in a significantly smaller proportion of other individuals.

Liver membrane antibodies (LMA) recognize a 26-kD protein on the hepatocellular surface

Sera from 82 patients with chronic inflammatory liver diseases and from patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and Hashimoto's thyroiditis were studied by immunoblotting against purified liver plasma membranes (LPM) and soluble liver protein (SLP) fractions from different species after previous separation by SDS-PAGE. Eighteen of 19 sera with LMA of IgG type in immunofluorescence assay and six LMA-negative sera (three sera from patients with RA) showed antibodies of the IgG or IgM classes against a protein with a molecular weight of 26 kD which was present in LPM and SLP fractions from rats, rabbits, pigs and humans. The reaction with 26-kD liver protein did not correlate with other known autoantibody-antigen systems. All sera were negative in the 26-kD region with liver mitochondria, liver microsomes and soluble proteins of kidney (with one exception), heart and gut from the rat. The 26-kD protein was purified by affinity chromatography on immobilized anti-26-kD protein antibodies from patients, eluted from the 26-kD band of immunoblots. Studies with purified 26-kD liver protein and with SLP as antigens after separation in two-dimensional electrophoresis confirmed that patient serum and experimental rabbit antiserum react with the same protein. Eluted patient antibodies and rabbit antisera showed a linear fluorescence pattern on isolated hepatocytes from rat and rabbit. The data indicate that one of the target antigens of LMA is a species-nonspecific 26-kD protein located on the hepatocellular surface.

Alcoholic liver disease

Liver injury may develop in some people who consume alcohol. The pathogenesis of liver damage in such subjects remains obscure. Major histopathologic features of alcohol-associated liver injury include steatosis, steatonecrosis, and cirrhosis. The clinical manifestations of alcoholic liver disease are nonspecific and range from asymptomatic hepatomegaly to stigmata of portal hypertension with advanced parenchymal failure. The severity of the clinical presentation and the degree of aminotransferase elevation correlate poorly with the liver histopathology, particularly in patients who continue to drink alcohol. Short-term mortality of such patients is best predicted by a composite of clinical and laboratory parameters that are influenced by alcohol consumption as well as by liver disease. Long-term prognosis is determined by residual damage to vital organs (that is, whether or not cirrhosis has developed) and whether or not the patient continues to drink. Current therapy of alcoholic liver disease includes abstinence and correction of nutritional deficiencies. Other therapies are experimental and are best utilized in the setting of controlled clinical trials.

In vivo effect of chronic ethanol abuse on membrane alpha 1-glycoprotein of lymphocytes and immune response to various stimulating agents

Data on the immune status of chronic alcoholic patients are rather conflicting probably due to the interference of liver disease and/or malnutrition on immune function. In order to avoid this kind of interference, peripheral lymphocytes from 12 chronic alcoholic patients in good nutritional status and without heavy liver damage and 15 healthy controls were examined in this study. Lymphocyte functional activity was evaluated by means of response to phytohemagglutinin, calcium ionophore A 23187, and autologous non-T-cells [autologous mixed lymphocyte reaction (AMLR)]. Phenotypical analysis was carried out by the indirect immunofluorescence technique using monoclonal antibodies specific to CD5 (mature T-lymphocytes), CD4 (helper/inducer T-lymphocytes), CD8 (suppressor/cytotoxic T-lymphocytes), glycoproteins, and an immunoglobulin fraction from rabbit directed to membrane alpha 1 acid glycoprotein (AGP) that is involved in T-cell activation process. Our results show significant impairment in AMLR while response to phytohemagglutinin, heterologous non-T-cells and carcinoma ionophore did not differ from controls. No differences were present in circulating T-lymphocytes expressing CD5, CD4, and CD8 on their membrane, whereas AGP-bearing lymphocytes were significantly lower in chronic alcoholics (14.4 +/- 8.6) than in controls (31.9 +/- 8.1; p less than 0.001). These results support the hypothesis of a direct action of alcohol on one of the pathways of lymphocyte activation and the role of the lymphocyte membrane AGP on the AMLR.

Alcohol, cancer, and immunomodulation

There is a great deal of epidemiological evidence indicating that chronic, excessive alcohol consumption is a major risk factor for cancers in humans. However, the experimental basis for the increased cancer risk associated with alcohol intake is not clear. Since it appears that ethanol alone is not carcinogenic, ethanol effects must be explained in terms of its modifying the actions of other causal agents. Current studies indicate that ethanol and its congeners may act as tumor promoters, thereby enhancing the effect of initiating carcinogens from the environment. Available evidence also shows that ethanol is immunosuppressive. Clearly, cirrhosis due to high, prolonged alcohol intake is an indicator of the immunosuppressive effects of ethanol. It is less clear that more moderate intakes of alcohol could have as profound an effect on immune systems. However, changes do occur yielding alterations in lymphocyte sensitivity to alcohol in vitro and in cell development, as shown by increased NK cell function at low concentrations. Since other conditions, such as cytotoxic drugs which suppress cellular immune functions, are clearly associated with increased cancer risk. It is intriguing to think that prolonged exposure to ethanol-induced immunosuppression may be a cofactor in the promotion of cancer. The tumor promotion may take place via a variety of mechanisms as discussed in this paper, including reduced host defenses by direct effects of ethanol, its metabolites, and/or malnutrition. It may be beneficial to test methods for immunostimulation in prolonged alcohol abusers, where cessation of use is unsuccessful or residual immunosuppression remains, to reduce the risk of development or growth of initiated tumors.

Treatment of alcoholic liver disease

With advances in our understanding of the pathophysiology of alcoholic liver disease, pharmacological treatments of some of the basic disease processes are now in sight. The most notable development has been the introduction of propylthiouracil for the treatment of alcoholic hepatitis. In a recent trial the mortality rate of patients treated with this drug was 62% lower than that of a control group. Its beneficial effects may stem not from its anti-thyroid properties but rather from other actions such as free radical scavenging. Corticosteroids now appear to have no place in the treatment of alcoholic liver disease. Anabolic steroids, however, show promise, though longer term trials are required before this can be confirmed. Colchicine, too, has been reported to improve survival in patients with established cirrhosis. More experience is required with this and other anti-inflammatory and anti-fibrogenic drugs. beta Adrenergic blocking drugs, such as propranolol, reduce portal venous pressure. In a trial among patients with alcoholic cirrhosis who had oesophageal varices, 39% of those receiving propranolol had not experienced a haemorrhage by 2 years compared with 74% in the control group. The mortality rates at this time were 28% and 49% respectively. Results of treatment once the first haemorrhage has occurred are less impressive. Treatment of the alcohol withdrawal syndrome in patients with liver disease is often problematic. The dose of any sedative should be reduced to 25-50% of the usual dose and sedatives should be avoided in patients who are encephalopathic. Once the patient has recovered from the acute illness, abstinence from alcohol remains the single most important factor that determines long term survival.

Differences of liver membrane antibody frequency in alcoholic liver disease. Detection of IgG and IgA classes using radioimmunoassay

The presence of liver membrane antibody in IgG and IgA was investigated by radioimmunoassay using isolated rabbit hepatocytes as target cells. This technique was more sensitive than the immunofluorescent method. IgG liver membrane antibodies were positive in 24% of patients with alcoholic liver disease. IgA liver membrane antibodies were detected in 58% of patients with alcoholic liver disease, whereas they were detected only in 21% of those with nonalcoholic liver disease, except for cases of autoimmune chronic active hepatitis. In alcoholic liver disease, IgA liver membrane antibodies were detected at a high frequency in a group of patients with alcoholic hepatitis and active cirrhosis (94%) as compared with that of fatty liver, hepatic fibrosis, and inactive cirrhosis (42%). These results suggest that alcoholic liver disease is characterized in part by a humoral immune response of IgA liver membrane antibodies.

Spontaneous and antibody-dependent cellular immune reactions to ethanol-altered hepatoma cells

Spontaneous cell-mediated cytotoxicity (SCMC), antibody-dependent cellular cytotoxicity (ADCC) and proliferative lymphocyte stimulation in alcoholic liver disease (ALD) were investigated. Peripheral blood lymphocytes (PBL) from eight patients with advanced ALD and nine normal controls were tested against hepatoma cells (PLC/PRF/5) as targets. Target cells were grown in either normal culture medium or medium supplemented with 1 and 5% ethanol, respectively, for 24 to 48 h. Ethanol-exposed hepatoma cells exhibited profound and characteristic morphological alterations. Ethanol preincubation, however, proved to be without effect on immune reactions. Provided that hepatoma cells are an appropriate model, we assume that the proposed immune reactions in ALD are based on metabolic interactions operative only in vivo but do not parallel morphological alterations of liver cells directly induced by ethanol.

Identification of alcohol abuse and alcoholism with biological parameters

The prevalence and incidence of heavy alcohol consumption are major problems which have been increasing in many countries in recent years. It is crucial for physicians to consistently identify early drinking problems as well as the various end disease states in order to minimize suffering and maximize recovery. This paper reviews the evolutionary development of clinical tools for detection of alcohol abuse. The focus is primarily on clinical/biochemical indicators of alcohol abuse, emphasizing but not limited to changes in hematological characteristics, liver enzyme activity, lipids, immune function factors, hormones, neurological factors, and some physically based tests. Use of test combinations and sophisticated statistical analysis of pattern changes in test batteries evidence increased diagnostic efficiency.

Cellular cytotoxicity against autologous hepatocytes in alcoholic liver disease

We tested lymphocyte cytotoxicity against autologous hepatocytes in patients with alcoholic liver disease (ALD). The following cytotoxicity values were found (mean +/- SEM): alcohol-induced steatosis with or without fibrosis 16.5 +/- 2% (n = 29), alcoholic cirrhosis 28 +/- 4% (n = 13), controls with normal liver histology or minimal changes 6 +/- 2% (n = 11). The differences were statistically significant (both forms of ALD versus controls p less than 0.005). T-cell as well as non-T-cell-enriched lymphocyte fractions showed increased cytotoxicity in ALD. We did not observe a correlation between cellular cytotoxicity and the degree of biochemical or histological alterations within the groups tested. Thus, our study demonstrating enhanced cellular cytotoxicity against autologous hepatocytes in ALD further supports the hypothesis that cellular immune reactions are involved in the pathogenesis of ALD, especially of alcoholic cirrhosis.

Liver membrane antibodies in alcoholic liver disease. II. Antibodies to ethanol-altered hepatocytes

Using an indirect immunofluorescence technique, circulating liver membrane antibodies against normal rabbit hepatocytes and ethanol-altered rabbit hepatocytes have been sought in a series of patients with histologically confirmed alcoholic liver disease. Liver membrane antibodies against normal hepatocytes were found in 18 (28%) of the 65 sera examined, but with ethanol-altered hepatocytes as substrate liver membrane antibodies were found in 48 (74%) of the sera. Isolation of F(ab')2 fragments confirmed that the positive results were due to antibody binding. Liver membrane antibodies against ethanol-altered hepatocytes are peculiar to alcoholic liver disease, and there is a similar incidence in the various histological types of alcoholic liver disease. Absorption studies suggest that the liver membrane antibodies are directed against new or altered antigens which are not present in normal hepatocytes. These new or altered antigens may also appear after pretreatment with other primary alcohols and seem likely to be induced by a haptenic effect of the alcohol or a metabolic break-down product. These studies represent a novel approach to the further investigation of the possible role of immunological mechanisms in alcohol-induced liver injury.

Detection of immunoglobulins G and A on the cell membrane of hepatocytes from patients with alcoholic liver disease

The presence of immunoglobulins (Ig) G, A, and M and of complement fractions (C3-C4) on the liver cell surface was investigated by direct immunofluorescence in 40 patients with alcoholic liver disease. IgG was detected on the liver cell membrane with a linear staining pattern in 29 patients. The percentage of IgG-positive hepatocytes correlated with transaminase activities, independently of the histological findings. IgA was demonstrable with a coarse granular staining pattern in 11 of the 14 cases with established cirrhosis. The finding of IgG bound to the hepatocyte surface in patients with alcohol-induced liver damage suggests that alcohol could be responsible for antigenic modifications of hepatocyte membrane with consequent triggering of a humoral immune response.