Antibodies to alcohol altered liver cell determinants in patients with alcoholic liver disease

Alcohol Dehydrogenase: An Autoantibody Target in Patients with Alcoholic Liver Disease

The link between alcohol consumption and liver disease is not direct and several factors including autoimmunity to hepatocyte components have been implicated. We have previously identified alcohol dehydrogenase (ADH) as an autoantigen in autoimmune liver disease and in a proportion of patients with alcoholic liver disease. The aim of the present study is to investigate the association between the presence of anti-ADH antibodies, alcohol consumption and severity of liver damage in alcoholic patients. The presence of antibodies to human ADH β2 and horse ADH was investigated in 108 patients with documented history of alcohol consumption and alcohol related liver disease, 86 being active alcohol abusers and 22 on sustained alcohol withdrawal, 39 with non-alcohol related disease and 22 normal subjects.

Antibodies to either ADH form were more frequently detected in active alcohol abusers (55/86, 64%) than in patients on sustained alcohol withdrawal longer than 6 months (1/8, 13%, p<0.005), HBV infection (2/8, 25%, P=0.03), non-alcohol related disease (9/29, 23%, p<0.0001) and in normal controls (3/22, 14%, p<0.0001); were more frequent in patients with cirrhosis than in those with steatosis (26/34, 76% vs 34/64, 53%, P=0.02); and were associated with elevated levels of ALT (anti-ADH β2, p<0.05), immunoglobulin A (p<0.05) and γ-glutamyl transpeptidase (P=0.01). Anti-ADH antibody positive serum samples were able to inhibit the enzymatic activity of ADH. These findings suggest that anti-ADH antibodies may be triggered by alcohol consumption and act as a disease activity marker in alcoholic liver disease.

Immune response to acetaldehyde-human serum albumin adduct among healthy subjects related to alcohol intake

Acetaldehyde (AA) is the main metabolic product in ethanol metabolism, although it can also derive from sources of airborne pollution. As a typical aldehyde, AA is able to react with a variety of molecular targets, including DNA and protein. This property justifies the hypothesis of a immune reaction against this kind of adduct, to be studied by a seroprevalence screening approach. In this study, the correlation between drinking habits and the amount of circulating AA-human serum albumin adduct (AA-HSA) was evaluated in a group of healthy subjects, non alcohol-addicted. Daily ethanol intake (grams) was inferred for each subject using the information collected through a questionnaire, and AA-HSA antibodies (AA-HSA ab) analyses were performed using the Displacement Assay on whole blood samples. The findings showed a correlation between ethanol intake and immune response to molecular adduct. These results underscore the evaluation of AA-HSA ab amount as a suitable molecular marker for alcohol intake that can be applied in future investigations on a large scale for prevention screening.

Oxidative stress in alcoholic liver disease: role of NADPH oxidase complex

Alcohol is a well-known risk factor for liver damage and is one of the major causes of liver disease worldwide. Chronic intake of alcohol, over a certain limit, inevitably leads to hepatic steatosis. If the injury persists, steatosis with concomitant tumor necrosis factor-alpha and other cytokines, progresses to steatohepatitis, fibrosis and finally cirrhosis. Among the multiple factors involved in the process of alcohol-induced liver injury, a crucial role is played by oxidative stress. Several mechanisms during ethanol metabolism result in reactive oxygen species (ROS) production. Although the main site of ethanol metabolism is hepatocytes, other mechanisms are involved in alcohol-induced liver injury. Specifically, in the ROS production activity, an important role is played by the NADPH oxidase complex. NADPH oxidase is expressed in hepatocytes, hepatic stellate cells and Kupffer cells in the liver. Studying NADPH oxidase gives new insights into alcohol-induced liver damage and provides new direction for future therapeutic strategies.

Alcohol, oxidative stress and free radical damage

The involvement of free radical mechanisms in the pathogenesis of alcoholic liver disease (ALD) is demonstrated by the detection of lipid peroxidation markers in the liver and the serum of patients with alcoholism, as well as by experiments in alcohol-feed rodents that show a relationship between alcohol-induced oxidative stress and the development of liver pathology. Ethanol-induced oxidative stress is the result of the combined impairment of antioxidant defences and the production of reactive oxygen species by the mitochondrial electron transport chain, the alcohol-inducible cytochrome P450 (CYP) 2E1 and activated phagocytes. Furthermore, hydroxyethyl free radicals (HER) are also generated during ethanol metabolism by CYP2E1. The mechanisms by which oxidative stress contributes to alcohol toxicity are still not completely understood. The available evidence indicates that, by favouring mitochondrial permeability transition, oxidative stress promotes hepatocyte necrosis and/or apoptosis and is implicated in the alcohol-induced sensitization of hepatocytes to the pro-apoptotic action of TNF-alpha. Moreover, oxidative mechanisms can contribute to liver fibrosis, by triggering the release of pro-fibrotic cytokines and collagen gene expression in hepatic stellate cells. Finally, the reactions of HER and lipid peroxidation products with hepatic proteins stimulate both humoral and cellular immune reactions and favour the breaking of self-tolerance during ALD. Thus, immune responses might represent the mechanism by which alcohol-induced oxidative stress contributes to the perpetuation of chronic hepatic inflammation. Together these observations provide a rationale for the possible clinical application of antioxidants in the therapy for ALD.

Review article: alcoholic liver disease--pathophysiological aspects and risk factors

BACKGROUND

Alcoholic liver disease has a known aetiology but a complex and incompletely known pathogenesis. It is an extremely common disease with significant morbidity and mortality, but the reason why only a relatively small proportion of heavy drinkers progress to advanced disease remains elusive.

AIM

To recognize the factors responsible for the development and progression of alcoholic liver disease, in the light of current knowledge on this matter.

METHODS

We performed a structured literature review identifying studies focusing on the complex pathogenetic pathway and risk factors of alcoholic liver disease. Results In addition to the cumulative amount of alcohol intake and alcohol consumption patterns, factors such as gender and ethnicity, genetic background, nutritional factors, energy metabolism abnormalities, oxidative stress, immunological mechanisms and hepatic co-morbid conditions play a key role in the genesis and progression of alcoholic liver injury.

CONCLUSIONS

Understanding the pathogenesis and risk factors of alcoholic liver disease should provide insight into the development of therapeutic strategies.

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.

T-cell activation, expression of adhesion molecules and response to ethanol in alcoholic cirrhosis

Abnormal immune function is a well-recognized feature in patients with alcoholic cirrhosis. It may contribute to the pathogenesis of the disease and to the clinical consequences. Nevertheless, a potential role of ethanol to elicit immune disturbances in patients is still unclear. To further examine the immune mechanisms which potentially are involved in alcoholic cirrhosis and the relationship to ethanol, we have determined the expression of surface antigens CD4, CD8, and of adhesion molecules CD25, LFA-1, ICAM-1 and LFA-3 in patients and in response to stimulation with OKT-3, IL-2 and with ethanol in vitro. In addition, we quantified the production of IL-2, TNF-alpha and IFN-gamma by lymphocytes of alcoholic cirrhosis patients compared to controls. Lymphocytes from patients showed increased basal and stimulated expression of CD4, CD25, LFA-1, ICAM-1 and LFA-3 molecules and increased TNF-alpha production in comparison to controls. When lymphocytes from patients were co-cultured with ethanol, the overexpression of activation markers and TNF-alpha production was similar to that obtained with mitogens. In contrast, a predominant suppressive effect of ethanol was observed in lymphocytes from controls. Our study underlines the importance of a chronic state of immune activation in alcoholic cirrhosis. The data further suggest a role of ethanol to stimulate immune response and to be directly involved in the development of disease.

Circulating IgA antibody against a 65 kDa heat shock protein in acute alcoholic hepatitis

Heat shock proteins are known to be immunogenic in a number of diverse conditions and can be induced by hypoxia, tumour necrosis factor and alcohol--all potential triggers in patients with acute alcoholic hepatitis. In the present study, sera from 23 patients with acute alcoholic hepatitis, 18 liver disease controls, ten patients with inactive alcoholic liver disease and six alcoholics without liver damage were screened for the antibody to a 65 kDa heat shock protein using an ELISA technique. IgA antibody was found to be closely associated with alcoholic hepatitis; 20/23 patients were seropositive compared to 5/18 liver disease controls and 4/10 with inactive alcoholic cirrhosis. IgM and IgG antibodies to the 65 kDa heat shock protein were less closely associated with alcoholic hepatitis and were positive in nine and eight of the 23 patients, respectively, compared with six and seven of 18 liver disease controls. Neither antibody was detected in alcoholics without liver damage or normal controls. These data indicate that an IgA immune mediated response to the 65 kDa heat shock protein is characteristic of patients with acute alcoholic hepatitis and may be one mechanism underlying observed persistence of liver damage after cessation of alcohol consumption.

Epidemiology of alcoholic liver disease

Although mortality from alcoholic liver disease has declined in some Western countries in recent years, elsewhere it is increasing and overall it remains a major health problem. Deaths are predominantly seen in patients with alcoholic hepatitis or cirrhosis, and when they occur in patients with fatty liver are usually unrelated to liver disease. Progression to cirrhosis is correlated with the severity of fatty liver and particularly with the presence of alcoholic hepatitis. Mortality from cirrhosis is strongly correlated with per capita alcohol consumption. The decline in cirrhosis mortality rates seen recently is related in part to decreases in per capita consumption, but probably also to the growth of self-help organizations which facilitate abstinence from alcohol. Recent studies suggest there is not an invariable dose-response relationship between alcohol intake and the severity of liver disease and that alcohol has a permissive effect which allows other aetiological factors to operate. Factors that influence susceptibility to alcoholic liver disease include gender (women develop alcoholic cirrhosis more readily than men), concomitant hepatitis C infection and possibly hepatitis B infection. It is uncertain whether HLA status or immune mechanisms are implicated. The systematic use of screening tests for hazardous consumption combined with early intervention therapies offers a good prospect of reducing morbidity and mortality from alcoholic liver disease.

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.

The associations of alcohol drinking and drinking cessation to measures of the immune system in middle-aged men

To estimate the association between the immunologic responses of the cell-mediated and humoral systems and alcohol drinking, we used data from the Vietnam Experience Study conducted by the Centers for Disease Control. That study, conducted from 1985 to 1986, was based on a random sample of 4462 male, Vietnam-era, U.S. veterans. By using linear regression, we evaluated how (1) the number of alcoholic drinks the subjects consumed per month and (2) the drinking cessation of certain subjects were associated with their relative and absolute T, B, CD4, and CD8 lymphocyte counts and immunoglobulin A (IgA), IgM, and IgG levels. We used geometric means and percentage differences in geometric means of immune status to measure the associations and adjusted these values to account for the effect of covariates. The results indicated that measures of immune status differed among the drinking categories and that, generally, the differences changed after adjustment for covariates. These differences consisted, as alcohol consumption increased, of higher IgA and IgM levels, relative T and CD4 lymphocytes, and the ratio of CD4 to CD8 cells, and of lower IgG levels, relative B and CD8 lymphocytes, absolute lymphocyte, and lymphocyte subset counts after adjusting for other covariates. Among former drinkers, we found no clear-cut pattern in measures of immunity for a few years after cessation and then found that values of former drinkers tended to return toward values of nondrinkers as they continued to abstain.

HCV infection, hepatic HLA display and composition of the mononuclear cell inflammatory infiltrate in chronic alcoholic liver disease

Viral infection may play a role in alcoholic liver disease with histological features of chronic active hepatitis (CAH). Human leucocyte antigen (HLA) hepatocellular display is supposed to allow HLA-restricted T-lymphocyte cytotoxicity in chronic viral hepatitis. We studied the presence of serum anti-hepatitis C virus (HCV) antibodies, the hepatic HLA display and the composition of the mononuclear cell infiltrate in 16 patients with alcoholic liver disease and histological features of CAH and in 11 patients with alcohol-related degenerative changes. All patients were negative for hepatitis B virus (HBV) markers. Anti-HCV were tested by microplate ELISA. Class I HLA A, B, class II HLA DR, lymphocytes pan T, T helper/inducer, T suppressor/cytotoxic, B, and K NK cells were stained on liver cryostat sections by monoclonal antibodies and double indirect immunoperoxidase. Anti-HCV were present in all the patients with features of CAH and absent in those with only degenerative changes. In livers with features of CAH the mononuclear cell infiltrate consisted largely of T lymphocytes with marked prevalence of suppressor/cytotoxic cells in periportal and lobular areas. K NK cells were rare. Class I HLA, diffusely displayed on bile duct epithelium and on sinusoidal cells, also appeared on liver cells in the areas of periportal and lobular necrosis, namely on the hepatocytes in close contact with suppressor/cytotoxic T cells. In livers with only degenerative changes class I HLA were diffusely displayed on bile duct epithelium and on sinusoidal cells but absent on the hepatocytes. In all the specimens HLA DR antigens were expressed on sinusoidal and inflammatory cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Low density lipoprotein derivatization by acetaldehyde affects lysine residues and the B/E receptor binding affinity

Acetaldehyde (AcA), the first metabolite in ethanol oxidation, forms covalent adducts with the free amino groups of various proteins. In this study, we examined how acetaldehyde modification affects the chemical and biological properties of the atherogenic low density lipoprotein (LDL). AcA modification did not alter the protein and lipid composition of LDL, but the AcA concentration used in the incubation correlated strongly with the electrophoretic mobility of acetaldehyde-treated LDL (AcA-LDL) (r = 0.97, p less than 0.001) and the percentage of the free amino groups in AcA-LDL (r = -0.90, p less than 0.01). Amino acid analysis of AcA-LDL showed that lysine was the predominant residue in LDL modified by AcA. Assays with monoclonal antibodies (MB47, 2b, 4G3, and C1.1) directed against different epitopes of the LDL apoprotein B suggested that AcA modification reduced the immunological recognition of the LDL receptor binding region and its vicinity. Also, the binding affinity of AcA-LDL to B/E receptors correlated negatively with the percentage of modified lysine residues in AcA-LDL (r = -0.96, p less than 0.001). The results suggest that AcA derivatizes the lysine residues of LDL, and thus decreases the B/E receptor binding affinity of LDL. However, major changes in LDL receptor binding were produced only with non-physiologically high concentrations of AcA, and, therefore, the role of the present findings in vivo remains uncertain.

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.

Antibodies against acetaldehyde-modified protein epitopes in human alcoholics

Acetaldehyde, the primary metabolite of ethanol, binds covalently to proteins forming condensation products which have been recently shown to be immunogenic. To assess whether an antibody response against acetaldehyde-modified protein epitopes is associated with alcoholic liver disease, the serum immunoreactivity against proteins modified in vitro by acetaldehyde and against the corresponding unmodified proteins was measured by an enzyme-linked immunosorbent assay in 58 alcoholics with varying degrees of liver damage. Alcoholics showed significantly higher titers against protein-acetaldehyde conjugates than against the unmodified protein, independent of the nature of the carrier protein. The highest titers occurred in alcoholic hepatitis patients. Sera of patients with chronic hepatitis of nonalcoholic origin and of healthy controls also reacted with acetaldehyde conjugates, but their titers were significantly lower than those in alcoholic hepatitis patients. Our data support the idea that binding of acetaldehyde to proteins in humans generates antigenic determinants which trigger a corresponding immune response against such epitopes and suggest that this humoral immune response may be implicated in autoantibody formation and liver damage associated with excessive alcohol consumption.

Acetaldehyde modification of low density lipoprotein accelerates its catabolism in man

Acetaldehyde (AcA), the first metabolite in ethanol oxidation, is chemically highly reactive and binds covalently to the free amino groups of various proteins. In this study, we examined the metabolism of acetaldehyde-modified LDL (AcA-LDL) in man. LDL was isolated from human volunteers, radiolabelled with either 125I or 131I, incubated in various AcA concentrations (Aca-LDL) and injected back into the donors simultaneously with LDL incubated in identical conditions but omitting AcA (C-LDL). Acetaldehyde treatment did not change the chemical composition, electrophoretic mobility or the flotation characteristics of LDL. The proportion of free amino groups of AcA-LDL, ranging from 97 to 54.5%, was negatively correlated with the final concentration of AcA used in the incubation medium (r = -0.99, P less than 0.001). AcA modification of LDL accelerated its in vivo catabolism in man in such a way that the fractional catabolic rate (FCR) for AcA-LDL was negatively correlated with the percentage of free amino groups in AcA-LDL (r = -0.87, P less than 0.01). The clearance of AcA-LDL modified in 0.4, 2.0, 4.0 and 8.0 mM AcA was 0.9, 1.4, 2.5 and 3.7 times faster than the clearance of C-LDL, respectively. If AcA-LDL is formed in man after ethanol ingestion, its rapid clearance may be one possible mechanism for the low LDL levels observed in chronic alcohol users.

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.

Monoclonal and polyclonal antibodies against acetaldehyde-containing epitopes in acetaldehyde-protein adducts

Immunization of mice with acetaldehyde conjugated to human plasma proteins resulted in the production of polyclonal antibodies that reacted with erythrocyte protein-acetaldehyde conjugates, but not with control erythrocyte proteins. Such antibodies recognized erythrocyte protein-acetaldehyde conjugates prepared with 20-100 microM acetaldehyde, concentrations that exist in the blood of alcoholics. The antibodies also recognized acetaldehyde condensation products with synthetic poly-(L-lysine). Immunization with keyhole limpet hemocyanin-acetaldehyde conjugates resulted in antibodies against both plasma protein-acetaldehyde and erythrocyte protein-acetaldehyde conjugates, which did not cross-react with the respective unmodified carrier proteins. Immunization with human erythrocyte protein-acetaldehyde condensates led to the production of antibodies against both the protein moiety as well as the condensate. Monoclonal antibodies with affinities 50 times greater for the condensate than for the carrier protein were produced by hybridization of spleen cells from the immunized mice. Chronic alcohol administration to mice for 45-50 days led to the generation of antibodies that reacted against protein-acetaldehyde conjugates, suggesting that such adducts are formed in vivo and can act as neoantigens. Antibodies against acetaldehyde adducts should be of value in the identification of alcohol consumption and in the study of the biology of the adducts in relation to organ pathology.

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.

Ethanol metabolism in the generation of new antigenic determinants on liver cells

Antibodies directed against ethanol altered liver cell components have been detected in the serum of nearly 50% of patients with alcoholic liver disease although the pathogenetic mechanisms are unclear. The importance of ethanol metabolism in the generation of new antigenic determinants on liver cells was investigated by in vivo inhibition of alcohol or acetaldehyde dehydrogenase and an induced cytotoxicity assay. There was a significant reduction in cytotoxicity to hepatocytes isolated from rabbits treated with ethanol 1 g/kg when the metabolism of ethanol to acetaldehyde by alcohol dehydrogenase was inhibited. In contrast when the oxidation of acetaldehyde was inhibited by disulfiram cytotoxicity was significantly enhanced. These results show that ethanol metabolism is integral to the expression of the ethanol related determinant and suggest that an impaired ability to metabolism acetaldehyde could lead to the development of immunological reactions to alcohol altered liver membrane antigens.

Acetaldehyde alone may initiate hepatocellular damage in acute alcoholic liver disease

Acetaldehyde may be the injurious agent in acute alcoholic liver disease. It has been suggested that the mechanism of liver injury in this situation may be immunologically mediated. In the present study acetaldehyde has been bound to human liver plasma membranes. The activation of C3 by the acetaldehyde/membrane product was measured by immunofixation of the separated C3 components. Activation of C3 by acetaldehyde exposed liver plasma membranes was increased to 16.4% compared with 6% by non-exposed membranes (p = 0.004). Human liver plasma membranes bound 212 +/- 18 nmol acetaldehyde per mg membrane protein. The binding constant was 439 +/- 81 microM. It is concluded that acetaldehyde bound to human liver plasma membranes activates the complement sequence and this may be the initial stage in the pathogenesis of acute alcoholic liver disease.

Serum antibodies against alcohol-treated rabbit hepatocytes in patients with alcoholic liver disease

The existence of antibodies against alcohol-treated rabbit hepatocytes in sera of patients with alcoholic liver disease was investigated utilizing a 125I-labelled protein A assay. The sera, after two absorptions with normal rabbit hepatocytes, were incubated with hepatocytes isolated from rabbits which had been treated for 4 days with a daily dose of ethanol (1 g/kg body weight) intravenously. Serum antibodies against alcohol-treated hepatocytes were detected in 21 of 55 patients with alcoholic liver disease; this was associated with a distinct, mixed granular and linear fluorescence staining the surface of alcohol-treated hepatocytes. By contrast, none of 23 patients with other liver diseases who had no history of excessive alcohol intake showed the antibodies in their sera. The values of the antibodies of patients with alcoholic active cirrhosis and alcoholic hepatitis were significantly higher than those of other types of alcoholic liver disease. These results showed that antibodies against alcohol-treated hepatocytes are present in alcoholic liver disease with inflammation. The role of these antibodies on liver cell damage in alcoholic liver disease remains to be clarified.

An enzyme-linked immunosorbent assay for detection of antibodies against halothane-altered hepatocyte antigens

Patients with massive liver cell necrosis that may follow halothane anaesthesia have a high incidence of circulating antibodies against halothane-induced hepatocyte antigens. In order to provide an objective and quantitative method for the detection of these antibodies, an enzyme-linked immunosorbent assay has been developed. Sera, after absorption with normal rabbit liver microsomal fraction, are tested for binding to microsomal fractions from control and halothane-pretreated rabbits. Those containing antibodies against halothane-induced determinants give significantly enhanced binding to halothane-altered fractions; this specificity was verified by absorption experiments. Using this method, halothane-related antibodies were detected in sera from 16/24 patients with halothane-associated liver failure, at titres ranging from 1:100 to 1:25600. Such antibodies were not detectable in sera from 26 normal blood donors, 5 healthy anaesthetists, 12 patients who had received multiple halothane anaesthetics but had normal liver function tests and 32 patients with a variety of other liver diseases. This rapid and reproducible assay should be of value for the detection of antibodies and for detailed investigation of patient antibody responses, and also for characterization of the route of production and metabolism of the antigen.