Alcoholism, infection and altered host defenses: a review of clinical and experimental observations

Nutrition in Alcoholic Liver Disease: An Update

Malnutrition is a change in body composition owing to disordered nutrition associated with a decrease in function and poor clinical outcomes. Malnutrition can result from overnutrition, undernutrition and inflammatory activity. Patients with alcoholic liver disease are at increased risk for malnutrition. In this article, we discuss the different methods used to assess malnutrition, prevalence of malnutrition, potential mechanisms underlying malnutrition, and its treatments in patients with alcoholic liver disease.

Coordinated histone H3 methylation and acetylation regulate physiologic and pathologic fas ligand gene expression in human CD4+ T cells

Activation-induced Fas ligand (FasL) mRNA expression in CD4+ T cells is mainly controlled at transcriptional initiation. To elucidate the epigenetic mechanisms regulating physiologic and pathologic FasL transcription, TCR stimulation-responsive promoter histone modifications in normal and alcohol-exposed primary human CD4+ T cells were examined. TCR stimulation of normal and alcohol-exposed cells led to discernible changes in promoter histone H3 lysine trimethylation, as documented by an increase in the levels of transcriptionally permissive histone 3 lysine 4 trimethylation and a concomitant decrease in the repressive histone 3 lysine 9 trimethylation. Moreover, acetylation of histone 3 lysine 9 (H3K9), a critical feature of the active promoter state that is opposed by histone 3 lysine 9 trimethylation, was significantly increased and was essentially mediated by the p300-histone acetyltransferase. Notably, the degree of these coordinated histone modifications and subsequent recruitment of transcription factors and RNA polymerase II were significantly enhanced in alcohol-exposed CD4+ T cells and were commensurate with the pathologic increase in the levels of FasL mRNA. The clinical relevance of these findings is further supported by CD4+ T cells obtained from individuals with a history of heavy alcohol consumption, which demonstrate significantly greater p300-dependent H3K9 acetylation and FasL expression. Overall, these data show that, in human CD4+ T cells, TCR stimulation induces a distinct promoter histone profile involving a coordinated cross-talk between histone 3 lysine 4 and H3K9 methylation and acetylation that dictates the transcriptional activation of FasL under physiologic, as well as pathologic, conditions of alcohol exposure.

Chronic alcohol exposure renders epithelial cells vulnerable to bacterial infection

Despite two centuries of reports linking alcohol consumption with enhanced susceptibility to bacterial infections and in particular gut-derived bacteria, there have been no studies or model systems to assess the impact of long-term alcohol exposure on the ability of the epithelial barrier to withstand bacterial infection. It is well established that acute alcohol exposure leads to reduction in tight and adherens junctions, which in turn leads to increases in epithelial cellular permeability to bacterial products, leading to endotoxemia and a variety of deleterious effects in both rodents and human. We hypothesized that reduced fortification at junctional structures should also reduce the epithelial barrier’s capacity to maintain its integrity in the face of bacterial challenge thus rendering epithelial cells more vulnerable to infection. In this study, we established a cell-culture based model system for long-term alcohol exposure to assess the impact of chronic alcohol exposure on the ability of Caco-2 intestinal epithelial cells to withstand infection when facing pathogenic bacteria under the intact or wounded conditions. We report that daily treatment with 0.2% ethanol for two months rendered Caco-2 cells far more susceptible to wound damage and cytotoxicity caused by most but not all bacterial pathogens tested in our studies. Consistent with acute alcohol exposure, long-term ethanol exposure also adversely impacted tight junction structures, but in contrast, it did not affect the adherens junction. Finally, alcohol-treated cells partially regained their ability to withstand infection when ethanol treatment was ceased for two weeks, indicating that alcohol’s deleterious effects on cells may be reversible.

Increased total serum IgE in alcoholics

Total serum IgE concentrations were measured in 106 male alcoholics with current alcohol abstinence of varying duration. The influence of smoking habits and clinical atopy on IgE levels was considered. The majority (91%) of the alcoholics were smokers and 26% suffered from possible clinical atopy. The geometric mean IgE in non-atopic, smoking alcoholics was 42 kU/l and significantly higher than the mean IgE level, 19 kU/l, in age-matched, smoking, non-atopic male participants in a general health survey (p less than 0.001). The IgE levels declined with the length of the alcohol abstinence period. Alcoholics, serially followed after a heavy drinking spree, showed a uniform pattern of declining IgE levels during a fortnight of abstinence (p less than 0.001). No link was noted between total IgE levels and the extent of liver affection as estimated by various serum variables (bilirubin, aminotransferases, gamma-GT, IgG, IgA and IgM) or galactose tolerance test. The increased IgE levels in alcoholics are suggested to reflect an influence of ethanol on T lymphocytes regulating the IgE synthesis. Such a proposed effect of ethanol on cellular immunity may contribute to certain organic alcohol diseases, but does not appear to influence the frequency of clinical atopy, being similar in our patient group and in the general population of the same geographic area.

Immunological and hematological abnormalities in chronic alcoholism

Thirty-two chronic alcoholics were studied immunologically and hematologically on the first hospital day after a period of excessive alcohol consumption. No patient had any signs of severe liver disease. All patients were tested for delayed skin hypersensitivity to PPD and mumps antigens. Quantitation of immunoglobulins and routine hematological tests were also performed. Fifteen and 23 patients did not respond to PPD and mumps antigens, respectively, compared to about 10 and 40% of anergic controls. Anergic patients had lower haptoglobin levels than skin-positive patients. Elevated IgM values were common. Thrombocytopenia was the most common (41%) hematological disturbance, while 19% of the patients were anemic.

Ethanol-induced CD3 and CD2 hyporesponsiveness of peripheral blood T lymphocytes

The functional relevance of a direct ethanol effect on the membrane structure of T lymphocytes and accessory cells (APC), as well as on signal transduction systems was studied in ten normal subjects. Ethanol incubation (80 mM for 24h) of highly purified T cells increased the number of CD4+/CD45RA+ lymphocytes. In contrast, ethanol exposure induced a drop in CD14+/LFA-3+ APC values. These changes were accompanied by faulty T-cell proliferation in response to anti-CD3 and anti-CD2 mAb and inhibition of CD3- and CD2-mediated rises in intracellular calcium and, to a lesser extent, inositol 1,4,5-triphosphate levels. These data clearly indicate that a membrane-specific ethanol interaction both modifies surface glycoproteic and/or glycolipidic structures and alters transmembrane transduction of the activation signals.

Ethanol inhibits methionine adenosyltransferase II activity and S-adenosylmethionine biosynthesis and enhances caspase-3-dependent cell death in T lymphocytes: relevance to alcohol-induced immunosuppression

An important aspect in alcohol abuse-associated immune suppression is the loss of T helper CD4(+) lymphocytes, leading to impairment of multiple immune functions. Our work has shown that ethanol can sensitize CD4(+) T lymphocytes to caspase-3-dependent activation-induced cell death (AICD). It has been demonstrated that the formation of S-adenosylmethionine (SAMe) catalyzed by methionine adenosyltransferase (MAT) II is essential for CD4(+) T-cell activation and proliferation. Since ethanol is known to affect SAMe metabolism in hepatocytes, we investigated the effect of ethanol on MAT II activity/expression, SAMe biosynthesis and cell survival in CD4(+) T lymphocytes. We demonstrate for the first time that ethanol at a physiologically relevant concentration (25 mM) substantially decreased the enzymatic activity of MAT II in T lymphocytes. Ethanol was observed to decrease the transcription of MAT2A, which encodes the catalytic subunit of MAT II and is vital for MAT II activity and SAMe biosynthesis. Furthermore, correspondent to its effect on MAT II, ethanol decreased intracellular SAMe levels and enhanced caspase-3-dependent AICD. Importantly, restoration of intracellular SAMe levels by exogenous SAMe supplementation considerably decreased both caspase-3 activity and apoptotic death in T lymphocytes. In conclusion, our data show that MAT II and SAMe are critical molecular components essential for CD4(+) T-cell survival that are affected by ethanol, leading to enhanced AICD. Furthermore, these studies provide a clinical paradigm for the development of much needed therapy using SAMe supplementation in the treatment of immune dysfunction induced by alcohol abuse.

Influence of alcohol on antimicrobial immunity

Prolonged consumption of excessive amounts of alcohol by itself, as well as possibly leading to a state of alcoholism, has been a long-standing biological/social problem. As a major public health concern, there is an estimated expenditure of about 20% of total health care costs for medical/hospital care related to alcohol-induced illness. In addition, a significant proportion of both men and women who are hospitalized can be classified as alcoholics. This review focuses primarily on one of the many biomedical problems attributed to alcohol abuse--its adverse effects on our immune-defense system. A considerable body of evidence has mounted, over the past several decades, indicating that those who abuse alcohol are more susceptible to certain infectious disorders and are more prone to bacteremia. Such infections tend to be continuous and are often associated with a high rate of mortality. Also, along these lines, various and suitable animal models have been developed to further elucidate what the causes are for the greater frequency and severity of infectious illnesses, and this review deals primarily with those studies linking alcohol abuse to disruption in the normal functioning of the host's immune surveillance system. Based on the results from both clinical and experimental studies, it would seem that exposure to high levels of alcohol causes decreased humoral and cellular immune responses, thereby seriously limiting our ability to be protected from certain infectious agents.

Impaired bactericidal activity and host resistance to Listeria monocytogenes and Borrelia burgdorferi in rats administered an acute oral regimen of ethanol

A rat model was used to examine how ethanol ingestion may interfere with antimicrobial immunity both in vitro and in vivo. Nonimmune Long-Evans rats were given a short-course treatment orally with excessive amounts of ethanol. Their spleens were removed at the time of sacrifice, and separate spleen cell suspensions were prepared and tested in vitro for their ability to kill two bacterial pathogens, Listeria monocytogenes and Borrelia burgdorferi. After the bacteria were mixed separately with various concentrations of spleen cells, it was found that spleen cells from the ethanol-treated rats killed fewer bacteria than matching pair-fed controls, based on counts of the number of cultured CFU (for Listeria) or based on microscopic examination (for Borrelia). For the in vivo studies, ethanol-treated and control rats were infected intraperitoneally with Listeria, and then, 1 to 3 days later, they were assessed for systemic infection based on the numbers of organisms present in their livers and spleens. Numbers of bacterial CFU for both organs were significantly higher in the group fed ethanol for the first 2 days after listerial challenge. These results support the concept that acute exposure to high levels of ethanol can impair host defense mechanisms, especially those expressed at the cellular level, which could lead to increased susceptibility to certain types of infections.

Differential STAT5 activation and phenotypic marker expression by immune cells following low levels of ethanol consumption in mice

Ethanol has been recognized as an immunosuppressive agent for many years. Effects of high levels of ethanol consumption on immune functions have been extensively studied, but little is known about the effects of low levels (scuh as 5% ethanol) of ethanol consumption. Herein we report that exposure of mice to 5% ethanol for 4-8 weeks decreases IL-2-augmented splenic NK cell activity, decreases the numbers of NK cells in spleen and liver, decreases the number of granulocytes (Gr-l+) in bone marrow and spleen, and decreases the percentages of B cells in liver. In contrast, the percentages of CD4+CD8+ thymocytes, CD4+CD8- splenocytes, CD4+CD8- liver nonparenchymal cells, CD3+ splenocytes, and CD3+ bone marrow cells were increased. Furthermore, exposure to 5% ethanol increases STAT5 activation in T cells and liver cells while decreases STAT5 activation in NK cells. Taken together, these findings suggest that low levels of ethanol consumption can differentially modulate immune cells in thymus, spleen, bone marrow and liver, which may be due to differential regulation of STAT5 activation by ethanol.

Diminished proliferation of B blast cell in response to cytokines in ethanol-consuming mice

We and others have demonstrated that ethanol suppresses the antibody response in humans and animals. The purpose of this study was to determine whether ethanol affects cytokine-induced proliferative responses of splenic B blast cells, and whether the decreased response was due to an imbalance of the cytokine activity. Thus, the ability of spleen cells from individual ethanol-diet-fed C57BL/6 mice to proliferate and produce cytokines was determined. The ability of anti-IgM monoclonal antibodies (mAb)-activated splenic B blast cells in response to mouse recombinant IL-2 (rIL-2) or rIL-4 was also assessed. A thymidine incorporation assay was used to determine cell proliferation, and the conventional bioassays for cytokine-dependent cell proliferation were used for determining the bioactivity of cytokines. Data were analyzed with general linear model procedure. Our results showed that ethanol weakened the proliferative response of B cells in response to mitogen as well as to mouse rIL-2 and rIL-4. The decreased B cell responses may result from an increase in the production of IL-4 by helper T cells. Finally, in the presence of excessive dose of rIL-4, the proliferative responses of B blast cells from all three groups of mice were diminished (p<0.01). Thus, our data clearly indicated that the diminished B cell proliferation in ethanol-consuming mice was due in part to an excessive amount of IL-4 produced and an inability of the B cell to interact properly with IL-4 that was secreted by helper T cells. The results should extend our basic understanding of the mechanism by which chronic alcoholism impairs the interactions and interdependence of T- and B-cell immune functions.

Pneumolysin-induced complement depletion during experimental pneumococcal bacteremia

To quantify complement depletion by pneumolysin during Streptococcus pneumoniae bacteremia, cirrhotic and control rats were infected intravenously with one of three isogenic mutant strains of S. pneumoniae expressing different forms of pneumolysin. Outcome measures included clearance of the organisms from the bloodstream, alterations in 50% serum hemolytic complement (CH(50)) activity and complement C3 levels during infection, and serum opsonic capacity at 18 h postinfection. Cirrhotic rats had significantly lower CH(50) and C3 levels than control rats, both before and after infection. However, initial complement levels did not predict bacterial load after 18 h of infection. Changes in CH(50) and C3 levels over the 18-h period correlated with numbers of H+C+ but not H+C- or PLY- organisms in the bloodstream at 18 h postinfection. The sera of cirrhotic rats infected with the H+C+ strain had significantly decreased levels of C3 and showed significantly lower opsonizing activity for S. pneumoniae than sera from H+C+-infected control rats. These studies suggest that under limiting concentrations of complement, the expression of pneumolysin by pneumococci has a significant, negative effect on serum complement levels and reduces serum opsonic activity.

Withdrawal syndromes

The pathophysiology of substance withdrawal is elucidated by a review of classic and cutting-edge research. The manifestation and evaluation of the associated withdrawal syndromes from ethanol, sedative-hypnotics, opioids, and baclofen, are compared. The general management of and pharmacotherapy for these patients are discussed.

Lipopolysaccharide-stimulated nitric oxide production and inhibition of cell proliferation is antagonized by ethanol in a clonal macrophage cell line

Both chronic and acute ethanol exposure have been shown to be cytotoxic and also to disrupt normal cell function or responses in a variety of cell types. Macrophage function has specifically been shown to be disrupted by chronic ethanol exposure by mechanisms that have not been elucidated. It is known that exposure of macrophages to lipopolysaccharide (LPS) from gram-negative bacteria will decrease the number of cells. Since increased exposure to endotoxin is often associated with chronic alcoholism, this may be one mechanism to account for loss of macrophages in alcoholic patients. The loss of macrophages, as a consequence of endotoxin treatment, appears to be linked to cell activation and, in particular, LPS-stimulated synthesis of nitric oxide which has been suggested to cause an increase in apoptosis. Ethanol also increases apoptosis in some cell types but, in general, ethanol inhibits activation of macrophages. Thus, the overall effect on cell numbers and cell proliferation elicited by treating macrophages concomitantly with ethanol and LPS depends on the balance between inhibiting LPS-mediated activation and the actions of ethanol. The interaction between ethanol and LPS was investigated in a macrophage cell line (RAW 264.7 cells) by measuring nitric oxide production and cell proliferation. A 24-h exposure to ethanol (100 mM) decreased [3H]-thymidine incorporation significantly. LPS treatment elicited a concentration-dependent decrease in [3H]-thymidine incorporation at LPS concentrations of 0.1 ng/ml to 1000 ng/ml and stimulated nitric oxide production at concentrations above 1 ng/ml. LPS-stimulated nitric oxide production was inhibited by ethanol (20 to 100 mM) and the nitric oxide synthesis inhibitor, N(G)Nitro-L-arginine methyl L-NAME) ester (100 and 500 microM). However, LPS-inhibited [3H]-thymidine incorporation was not be totally reversed by ethanol- or L-NAME-treatment. A direct correlation between nitric oxide production and inhibition of cell proliferation could not be demonstrated. However, it appears that ethanol and LPS do affect some common mechanism(s) in this cell line.

Nutritional support in alcoholic cirrhotic patients improves host defenses

BACKGROUND

Malnutrition is usual in patients with alcoholic liver disease and is associated with a poor outcome. Nutritional support decreases nutrition-associated complications.

AIM

To demonstrate that nutritional support in ambulatory alcoholic cirrhotic patients improves host defenses.

METHODS

Thirty-one male outpatients with alcoholic cirrhosis CHILD-PUGH B or C were included. Twenty-five subjects completed six months consuming daily a nutritional supplement (Ensure, 1000 Kcal and 35 g protein), in addition to their regular diet. At entrance and every three months, a clinical assessment, nutritional evaluation and indirect calorimetry were performed. Liver function tests and LPS-induced monocyte production of cytokines, salivary secretory IgA, lactulose/mannitol ratio and breath hydrogen tests were also measured in these intervals. Delayed cutaneous hypersensitivity and IgG and IgM antibody response to endotoxin were assessed at entrance and at the end of the study.

RESULTS

Patients drank 85% of the provided supplement as an average. REE, total body fat and serum albumin increased, basal breath hydrogen decreased and cellular immunity improved significantly during the follow up period (p< or =0.03). All the other parameters remained unchanged throughout the study. Six patients (16.2%) died during the study, five due to upper gastrointestinal bleeding.

CONCLUSION

Nutritional support in alcoholic cirrhotic patients improves nutritional status and cell mediated immunity.

Ethanol-Induced Macrophage Apoptosis: The Role of TGF-β

Both clinical and laboratory reports indicate that ethanol addicts are prone to recurrent infections. We hypothesize that ethanol promotes macrophage apoptosis, thus compromising the efficiency of the mononuclear phagocyte system in dealing with infection. We studied the effect of ethanol on macrophage apoptosis. Human monocytes isolated from healthy subjects after an alcohol drinking binge showed enhanced apoptosis (before, 1.2 ± 0.3% vs after, 28.4 ± 3.7% apoptotic cells/field). Peritoneal macrophages harvested from ethanol-treated rats also showed increased (p &lt; 0.0001) apoptosis. DNA isolated from peritoneal macrophages of ethanol-treated rats displayed integer multiples of 200 base pairs (ladder pattern). Furthermore, macrophages harvested from ethanol-treated rats had an enhanced expression as well as accumulation of TGF-β. In in vitro studies, ethanol promoted apoptosis of human monocytes as well as rat peritoneal macrophages. In addition, ethanol enhanced apoptosis of murine macrophages (J774) in a time-dependent manner. The ethanol-induced apoptosis was amplified by LPS and partly attenuated (p &lt; 0.001) by anti-TGF-β Ab. TGF-β also promoted macrophage apoptosis in a dose-dependent manner. Moreover, ethanol enhanced TGF-β protein production by macrophages. These results indicate that ethanol promotes macrophage apoptosis. This effect of ethanol seems to be partly mediated through the generation of TGF-β by macrophages.

Ethanol impairs major histocompatibility complex (MHC) class II molecule-mediated but not MHC class I molecule-mediated T cell response in alcohol-consuming mice

The goal of this study was to determine whether alcohol affects alloantigen-induced proliferative and cytolytic activity of T cells in mice, and whether the altered immune response was in part due to a defect of IL-2 activity. The ability of spleen cells from individual alcohol-consuming C57BL/6 mice to generate allo-specific mixed lymphocyte response (MLR) and cytotoxic T lymphocyte (CTL) was compared to that of mice fed on an isocaloric maltose diet and regular diet. Allospecific MLR and CTL were generated by sensitizing spleen cells of C57BL/6 mice against spleen cells from BALB/c mice, and the allo-specific CTL activity was determined by the ability of the CTL to kill 51Cr-labeled P815 mastocytoma target cells. Our results showed that the allo-specific MLR of the responder cells from alcohol-consuming mice was significantly reduced (40% reduction, p<0.0 1), and the addition of exogenous interleukin 2 (IL-2) could not reverse the suppression of MLR induced by ethanol. However, our results clearly showed that ethanol has little suppressive effect on allo-reactive CTL of alcohol-consuming mice as compared to the alloreactivity of the control mice (P>0.05). Finally, we also demonstrated that ethanol did not impair the alloantigen-induced IL-2 production in the mixed lymphocyte cultures (P>0.1).

Host response to mycobacterial infection in the alcoholic rat: male and female dimorphism

Increased susceptibility to tuberculosis occurs in the alcoholic. One explanation for the altered susceptibility is a change in T-lymphocyte modulation. To evaluate this, 24 male and 24 female Sprague-Dawley rats were treated with either a Lieber-type liquid ethanol diet (LED) or an isocaloric control (LCD). After 2 weeks, half the subjects were infected with BCG (10(8) colony-forming units) and sacrificed after 42 days. Splenic helper (CD4) and suppressor/cytoxic (CD8) cells were quantitated by flow cytometry. By three-way analysis of variance, splenic cellularity was significantly increased by infection (p < 0.0001) but suppressed by LED (p = 0.0002). There was a marginal sexual difference (p = 0.065) with females exhibiting a 35% lower response while on alcohol. Examining lymphocyte subsets, the most significant changes were observed after infection (BCG) and alcohol treatment (LED). CD4 levels were diminished by LED (p = 0.0002) but markedly increased by infection (p < 0.0001), producing a highly significant interaction that affected both absolute number (p < 0.0001) and relative percent present (p = 0.0078). CD8 was influenced only by infection (p < 0.0001). This resulted in a infection-related increase in the CD4/CD8 ratio which was lower with LED (p = 0.0032). Splenic T-lymphocytes, predominately CD4, are involved in the host response to BCG hepatitis and are adversely influenced by LED, which may contribute to increased susceptibility.

Altered T-lymphocyte responsiveness to polyclonal cell activators is responsible for liver cell necrosis in alcohol-fed rats

The role of T-cell activation in alcoholic liver disease was investigated in rats fed alcohol and subsequently exposed to concanavalin A (Con A). Following Con A injection (20 mg/kg body weight), greater increases in liver-to-body weight ratio and ALT levels were observed at 12 and 24 hr in rats fed ethanol, compared with control rats fed sucrose. Furthermore, increases in serum interleukin-6 and tumor necrosis factor-alpha levels were noted in ethanol-fed rats, with maximal levels detected at 4 hr declining thereafter, but remaining above control levels at 24 hr. Analysis of T-cell subpopulations showed an increased percentage of CD4+, CD5+, and CD8+ T cells in blood from all groups, but not in liver perfusate. In contrast, a significant increase in the percentage of activated CD25+ T cells was detected in both blood and liver perfusate from rats fed ethanol even 24 hr after Con A injection. When CD4+ and CD8+ T cells from liver perfusate were cultured in the absence or presence of Con A, an increase in interleukin-6 and tumor necrosis factor-alpha production in supernatants was observed in ethanol-fed rats. In cultures stimulated with Con A, a 2- to 8-fold increase in cytokine production was detected, with intrahepatic CD4+ T cells being the major source. Immunohistological analysis revealed infiltration of CD4+ T cells around portal vein and central vein areas associated with fatty liver and severe hepatic necrosis. The results suggest that alcohol consumption induced a dysregulated T-cell population that mediated hepatic necrosis following polyclonal activation with Con A.

A low concentration of ethanol reduces the chemiluminescence of human granulocytes and monocytes but not the tumor necrosis factor alpha production by monocytes after endotoxin stimulation

The ability of polymorphonuclear neutrophils (PMNs) and monocytes (Mphi) to produce reactive oxygen species (ROS) has been related closely to their potential in the killing of microorganisms. Ethanol has been shown to impair the generation of ROS in these phagocytes after stimulation with some immunogens and to increase the susceptibility of alcohol abusers to infectious diseases. As endotoxemia is common in alcohol abusers, we investigated the effect of ethanol (21.7 mmol/liter) on the luminol-amplified chemiluminescence of PMNs and Mphi after endotoxin stimulation and the release of tumor necrosis factor alpha (TNF-alpha) from Mphi. Further, the efficiency of ethanol to inactivate chemically generated ROS was tested. Significant stimulation of ROS release occurred at endotoxin concentrations of 1 ng/ml or higher in both PMNs and Mphi. Ethanol significantly suppressed the formation of ROS in both cell types, the decrease being more pronounced in Mphi (-73. 8%) than in PMNs (-45.7%). The correlations between endotoxin concentration and the amount of released ROS showed a dose-dependent, sigmoidal course. Concentrations of endotoxin necessary for half-maximum stimulation were nearly identical (6 to 8 ng/ml) in both PMNs and Mphi, independent of the presence of ethanol. In contrast to ROS formation, ethanol had no effect on the amount of TNF-alpha produced by endotoxin-stimulated Mphi. Ethanol was shown to be unable to decrease the levels of chemically generated ROS under physiological conditions. Therefore, ethanol cannot be assumed to be an "antioxidative" compound but rather seems to modify processes of endotoxin recognition, intracellular signal transduction, or metabolism.

Oropharynx microbiota among alcoholics and non-alcoholics

CONTEXT

The oropharynx microbiota plays an important role in the origin of infections, especially among alcoholics whose airway defenses are impaired.

OBJECTIVE

To compare the normal oropharingeal flora in heavy alcohol drinker and non-alcoholics.

PATIENTS

117 persons, 58 heavy alcohol drinkers and 59 non-alcoholics.

SETTING

Santa Casa de São Paulo Emergency Service.

DESIGN

A blind prospective study.

MAIN OUTCOMES MEASURES

Prevalence of aerobic and anaerobic bacteria, and fungi.

RESULTS

The study of the oropharynx microbiota among heavy alcohol drinkers demonstrated the presence of anaerobic microorganisms in 84.5% of them, including: Bacteroides sp, Prevotella melaninogenica, Fusobacterium sp, Veilonella sp, Peptostreptococcus sp, Propionibacterium sp, Bifidobacterium sp and Clostridium sp, versus 30.5% (p < 0.005) of non-alcoholics. Candida sp was present in 34.5% of heavy alcohol drinkers and 5.1% of non-alcoholics (p < 0.005). Enterobacteria predominated among heavy alcohol drinkers (25%) compared with non-alcoholics (5.5%) only in the age group 14 to 34 years (p < 0.05).

CONCLUSION

Based upon these results, it was possible to conclude that the knowledge of the oropharynx microbiota among heavy drinkers and non-alcoholics has an important predictive value concerning probable etiologic agents of lower airway infections. Infections caused by anaerobic microorganisms and fungi should be taken into consideration during the choice of empirical therapy for heavy alcohol drinkers.

Ethanol impairs the induction of delayed hypersensitivity in C57BL/6 mice

Excessive alcohol consumption impairs T-cell-dependent immune function. Whether this impairment results from the direct inhibition of helper T (Th) cells or from inhibition of the cells that process and present antigen to Th cells is unclear. The present study examines the temporal effect of dietary alcohol on the development of delayed hypersensitivity (DTH) in C57BL/6 mice. We find that ethanol consumption just prior to and during the cognitive phase of the immune response impairs the development of a DTH response. Ethanol consumption initiated after the cognitive phase and during the effector phase of the immune response has no significant effect upon the elicitation of a DTH response. The results suggest that significant ethanol-induced impairment of DTH responses occurs during the cognitive phase of the immune response, when antigen presentation and recognition occur.

Ethanol ingestion impairs neutrophil bactericidal mechanisms against Streptococcus pneumoniae

Ethanol ingestion impairs both killing of selected pneumococcal strains by rat polymorphonuclear leukocytes (PMNL) in vitro and clearance of these same strains from experimentally infected rat lungs. To determine the mechanism(s) of this impairment, we isolated neutrophils (PMNL) by a magnetic cell sorting technique from the peripheral blood of chow-fed rats (C-PMNL) or rats pair fed for 7 days with a liquid diet providing 36% of its calories as either ethanol (E-PMNL) or dextrin-maltose (P-PMNL). Phagocytosis of fluorochrome-labeled bacteria and oxygen radical production, as determined by oxidation of dihydrorhodamine 123, were measured by flow cytometry. Degranulation, as determined by lysozyme release, was measured as lysis of a suspension of Micrococcus lysodeikticus. E-PMNL, P-PMNL, and C-PMNL were equivalent in their ability to phagocytose pneumococci and to produce an oxidative burst in response to stimulation by opsonized zymosan. However, E-PMNL produced fewer oxygen radicals and released less lysozyme than either P-PMNL or C-PMNL when stimulated by exposure to S. pneumoniae. There was no difference in oxygen radical production by E-PMNL and P-PMNL when stimulated with phorbol myristate acetate, but both cell types mounted a significantly reduced response in comparison to C-PMNL. These data suggest that ingestion of ethanol for 7 days significantly reduces both the oxidative burst and degranulation of rat PMNL in response to S. pneumoniae, thereby compromising anti-pneumococcal activity.

Neopterin levels in alcohol-dependent patients

Chronic alcohol exposure appears to suppress cell-mediated immunity which may contribute to the high incidence of infections among alcohol-dependent patients. We measured serum neopterin, as a marker of macrophage function and T-lymphocyte activation, in 26 alcohol-dependent patients. The mean serum neopterin in these patients was significantly lower than the mean serum neopterin in matched controls. In those who abstained, the mean serum neopterin at 3 weeks rose and was no longer significantly different from controls. Our findings suggest that alcohol-dependent patients have suppressed macrophage function which may be reversible within 3 weeks of abstention.

Gender differences in phagocytic responses in the blood and liver, and the generation of cytokine-induced neutrophil chemoattractant in the liver of acutely ethanol-intoxicated rats

Phagocytosis by circulating and liver-recruited polymorphonuclear leukocytes (PMNs) and Kupffer cells was studied in acutely ethanol-intoxicated, age-matched male and female rats. Acute ethanol intoxication in female rats is associated with a more effective phagocytic PMN response in the circulating blood, but with lower phagocytic activities by liver-recruited PMNs and Kupffer cells than in their male counterparts. Endotoxin [lipopolysaccharide (LPS)] treatment (consisting of a 90-min intravenous infusion of a nonlethal dose) of acutely ethanol-intoxicated male and female rats results in enhanced phagocytic responses in liver-sequestered PMNs and Kupffer cells, but not in circulating PMNs. However, the LPS challenge elicits a lesser phagocytic response in liver PMNs and Kupffer cells of female rats than in males. Significant gender differences exist in the extent of hepatic PMN infiltration in ethanol plus LPS-treated rats, which is paralleled by very similar differences in CD11b/c adhesion molecule expression in circulating PMNs and cytokine-induced neutrophil chemoattractant generation by hepatocytes and Kupffer cells. Taken together, these data indicate a smaller phagocytic response to fight infection in the liver of acutely alcohol-intoxicated female rats, but also a mechanism to afford some protection against neutrophil-associated tissue injury.

Effects of exogenous cytokines on the ethanol-mediated suppression of murine thymocyte proliferation

Although attempts have been made to assess the effect of ethanol on murine thymocyte proliferation, the mechanism which accounts for the immunosuppressive effect of ethanol on the thymocyte proliferation has not been elucidated. Thus, a mouse model was used to determine (1) whether there is a similarity in the effect of ethanol exposure in vitro and in vivo on the proliferative response of thymocytes to phytohemagglutinin (PHA), (2) whether ethanol exposure affects the responsiveness of thymocytes to exogenous interleukin (IL)-1 and IL-2, and (3) whether ethanol affects IL-1 production by peritoneal macrophages. We found that the proliferative response of thymocytes from mice fed on an ethanol-containing diet was significantly inhibited (P < 0.05) compared to that in mice fed on maltose or standard diets. We also observed that low concentrations of ethanol (12.5 mM) appeared to enhance the mitogenic response of thymocytes to PHA, but the response was not significantly greater than that of controls (P > 0.05). Ethanol at higher concentrations (25-100 mM) significantly suppressed the mitogenic response of thymocytes to PHA (P < 0.05) in a dose-dependent manner. Our data also revealed that (1) ethanol did not significantly suppress IL-1 secretion by adherent macrophages stimulated by LPS, and (2) the addition of exogenous IL-1 was insufficient to restore full responsiveness in thymocytes from ethanol-fed mice. Taken together, these results suggest that the suppressive effect of ethanol on thymocyte proliferation is not mediated by insufficient IL-1. Finally, we present novel evidence that addition of exogenous IL-2 completely restores the impaired proliferative response of thymocytes from ethanol-fed mice to control levels. In summary, our results demonstrate that ethanol inhibits thymocyte proliferation in response to PHA, and that the inhibition is not due to insufficient IL-1. We also report that addition of exogenous IL-2 is sufficient to restore full proliferative capacity to thymocytes from ethanol-fed mice.

Alcohol consumption as a cofactor in the progression of HIV infection and AIDS

Alcohol consumption as a cofactor in the progression of HIV infection was examined in 1,446 homosexual and bisexual HIV + men enrolled in the Multicenter AIDS Cohort Study who had a minimum of three visits. Two measures of drinking were employed: initial level, and pattern during the study period. Outcome measures included AIDS-related symptoms and AIDS diagnosis. Level of drinking at entry to the study was not significantly associated with either AIDS-related symptoms at final visit or with AIDS diagnosis. However, men who decreased drinking were more likely to report thrush, fatigue, weight loss, and diarrhea at their final visit. Most likely, these men decreased drinking as a result of failing health, not because their drinking pattern influenced symptom onset. These data support earlier reports that found no relationship between alcohol consumption and progression to AIDS.

Rabbit polymorphonuclear granulocyte function during ethanol administration--migration and oxidative responses in a joint with immune complex synovitis

Functional impairments of polymorphonuclear granulocytes (PMN) are believed to contribute to hampered inflammation and host defence in alcoholics. We studied effects of i.v. ethanol administration on PMN responses in rabbits during induction of a knee-joint synovitis. The synovitis conferred systemic effects, since chemiluminescent responses of peripheral blood PMN to opsonized zymosan and phorpbol myristate acetate (PMA) increased 6.4- and 17.9-fold, respectively. Chemiluminescent responses of synovial PMN were further amplified. This up-regulation was reduced to 33% in rabbits treated with ethanol when opsonized zymosan was used as the PMN stimulus; in contrast, PMA responses were unaffected. The appearance and migration of PMN to the synovitis joint were normal despite a blood ethanol concentration of 0.5%. Thus, ethanol impaired release of oxygen metabolites from PMN, but not the delivery of cells at an inflammatory site.

Alcohol ingestion impairs host defenses predisposing otherwise healthy mice to Pneumocystis carinii infection

Pulmonary infection with Pneumocystis carinii, an opportunistic pathogen, is associated with a variety of immunosuppressive states, including human immunodeficiency virus infection. We hypothesized that alcohol ingestion might compromise host defenses against this pathogen and, in an immunocompromised host, increase the severity of infection. This hypothesis was tested in both acute and chronic ethanol-treated normal and CD4+ T-cell-depleted mice challenged with P. carinii organisms. Normal and CD4+ T-cell-depleted mice were given an intraperitoneal injection of ethanol or saline 0.5 hr before P. carinii challenge and killed 3 hr later for bronchoalveolar lavage. Acute alcohol treatment decreased significantly tumor necrosis factor (TNF) activity and the number of polymorphonuclear leukocytes (PMNLs) recovered in the lavage in response to the pathogen. Depletion of CD4+ T-cells did not potentiate the effect of alcohol on the early inflammatory response to the pathogen any further. In normal animals, in vivo interferon (IFN)-gamma pretreatment augmented significantly the P. carinii-stimulated lung TNF response and PMNL recruitment. However, IFN-gamma pretreatment prevented the alcohol-induced suppression of TNF secretion without affecting the PMNL recruitment. The effect of chronic alcohol consumption on the severity of infection was studied in long-term, alcohol-fed normal and CD(4+)-depleted mice challenged with P. carinii organisms. Lung histopathology showed that P. carinii infection was present in > 60% of the alcohol-fed mice and in none of the controls. Also, a significantly higher number of PMNLs were recovered in the lavage fluid of alcohol-fed mice with persistent infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetaldehyde-serum protein adducts inhibit interleukin-2 secretion in concanavalin A-stimulated murine splenocytes: a potential common pathway for ethanol-induced immunomodulation

Variable immunobiological changes occur with alcohol consumption. Previous studies have shown that acetaldehyde forms stable adducts with serum proteins, including albumin. These adducts are elevated in persons and animals consuming ethanol. We examined the effect of serum protein-acetaldehyde adducts formed with fetal bovine serum (FBS) on concanavalin A-stimulated murine splenocytes. Interleukin-2 (IL-2) secretion and IL-2 receptor (IL-2R) expression were determined as a function of the effect of the acetaldehyde-protein adduct(s). FBS was incubated with acetaldehyde (500, 100, 50, 25, 10, and 0 microM) for 1 hr at 37 degrees C. Excess acetaldehyde was removed by ultrafiltration using a 500 molecular weight cut-off membrane in 3 volumes. Free as well as bound acetaldehyde was quantified using fluorigenic HPLC before and after incubation. Recovered acetaldehyde correlated with the amount added (r2 = 0.996). Splenocytes were cultured for 48 hr in complete medium containing 5% acetaldehyde-treated and 5% untreated FBS with 4 micrograms/ml concanavalin A. Although cell viability was unchanged, acetaldehyde-treated FBS mixed with native FBS decreased IL-2 secretion in a dose-dependent manner. The percentage of cells expressing IL-2R was reduced only at the highest acetaldehyde-FBS dose. Therefore, immunological effects ascribed to ethanol may result in part from the toxic properties of acetaldehyde-protein adducts on IL-2 secretion.

Ethanol suppresses Mycobacteria tuberculosis-induced mRNA for nitric oxide synthase in alveolar macrophages, in vivo

Acute ingestion of alcohol [ethanol (ETOH)] adversely affects the immunocompetence of both naive individuals as well as chronic alcohol abusers. An increased incidence and severity of tuberculosis is found in chronic alcohol abusers. Nitric oxide (NO) produced by alveolar macrophages (AMs) may play a role in the in vitro killing of Mycobacterium avium and Mycobacterium tuberculosis (MTB). Moreover, tumor necrosis factor-alpha (TNF-alpha) is believed to be a primary cytokine mediator of NO production by AMs. Recent studies from our laboratory demonstrated that ETOH suppressed endotoxin-induced increases in both TNF-alpha and NO in AMs, in vivo. We tested the postulate that acute ingestion of ETOH can interfere with mycobacteria-induced upregulation of the NO system in AMs, in vivo. We show that heat-killed M. avium complex (MAC) and human virulent MTB instilled into rat lungs rapidly increased mRNA for inducible NO synthase II (iNOS) of AMs in fluid obtained by bronchoalveolar lavage (BAL fluid). This was associated with production of reactive nitrogen intermediates [(RNIs); NO2- and NO3-] in BAL fluid, lung homogenate, and AMs in the absence of a significant increase in BAL fluid TNF-alpha. A single dose of ETOH (5.5 g/kg, ip) administered 30 min before intratracheal administration of MAC or MTB attenuated both MAC and MTB-induced increases in RNI in BAL fluid, lung, and AMs, and the increase in mRNA for iNOS. Thus, mycobacteria upregulate iNOS mRNA and enhance RNI production by AMs without any increase in the production of TNF-alpha. Moreover, ETOH attenuates mycobacteria-induced upregulation of mRNA for iNOS and RNI production in the absence of ETOH-mediated suppression of TNF. Speculatively, ETOH-mediated inhibition of the AM NO system may offer an explanation for the increased severity of mycobacterial infections in alcoholics.

Chronic ethanol intake and burn injury: evidence for synergistic alteration in gut and immune integrity

OBJECTIVE

Chronic ethanol (EtOH) intake and injury are both associated with increased susceptibility to infection in the host. This study examined the immune and gastrointestinal alterations induced by chronic EtOH intake and injury, and compared the effects of enteral and intravenous administration of EtOH.

DESIGN

Rats received 20% EtOH daily for 14 days by gavage [oral (PO)] or superior vena cava [intravenous (i.v.)] infusion. Mean blood EtOH concentrations at 90 minutes after administration were 95.3 mg/dL (PO) and 94.4 mg/dL (i.v.). An additional group of animals underwent a 30% total body surface area full-thickness burn injury 4 hours after the final dose of EtOH or normal saline on experimental day 14. All animals were killed 4 days after burn injury.

MATERIALS AND METHODS

Nonadherent splenic lymphocytes were tested for mitogenic responses to the T-cell mitogens concanavalin A (ConA) and phytohemagglutinin (PHA), and the B-cell mitogens lipopolysaccharide (LPS) and pokeweed. Quantitative bacterial cultures of mesenteric lymph nodes and liver were also performed. Alterations of intestinal mucosa were determined by measurement of ileal mucosal weight, DNA, protein, and diamine oxidase content. Circulating plasma endotoxin concentrations were also measured.

MEASUREMENTS AND MAIN RESULTS

Chronic PO-EtOH intake induced a significant impairment in mitogenic response to T-cell mitogens, with a fourfold reduction in ConA and a twofold reduction in PHA response (p < 0.05 by analysis of variance) and increased bacterial translocation (70% vs. 10%). Chronic EtOH administered by the i.v. route did not reduce mitogenic response to any of the mitogens studied. Histologic examination of ileal segments demonstrated that chronic PO-EtOH administration was associated with significant mucosal disruption and exfoliation. Chronic administration of PO-EtOH prior to burn injury induced a significant impairment in spleen mitogenic response to ConA, PHA, and LPS when compared with all other burn injury groups. Chronic administration of EtOH by the i.v. route prior to burn injury did not alter splenic mitogenesis. In addition, chronic PO-EtOH prior to burn injury increased bacterial translocation rates (80% vs. 33%) and prevented the normal intestinal reparative response to burn injury (demonstrated by a significant reduction in ileal mucosal weight, DNA, and diamine oxidase content).

CONCLUSIONS

Enteral but not i.v. administration of EtOH induced significant immunologic dysfunction (demonstrated by altered spleen mitogenic response) and gastrointestinal dysfunction (demonstrated by depressed ileal mucosal weight, DNA, and diamine oxidase content, and increased bacterial translocation rates). In addition, the administration of chronic enteral EtOH prior to injury resulted in significant immune suppression and impaired the host's ability for normal intestinal repair. These results suggest that this EtOH-induced reduction in immunocompetence may be gut-mediated and that the administration of alcohol prior to injury may result in a synergistic alteration of gut and immune integrity.

Rapidly fatal outcome of bacteremic Klebsiella pneumoniae pneumonia in alcoholics

Twenty-eight alcoholic patients with community-acquired pneumonia who were admitted to a referral medical center during a 3-year period were reviewed. All were men and with few exceptions were heavy smokers. The overall mortality was 64.3%. The most dramatic group was that of 11 patients (39.3%) with bacteremic Klebsiella pneumoniae pneumonia (BKPP), which had high mortality rate (100%), short onset of illness before hospital admission (42.6 +/- 8.2 h, mean +/- SD), and short survival time after the admission (24.6 +/- 7.9 h). All these 11 patients needed intensive care unit (ICU) management and ventilatory support. ARterial blood gas values showed marked hypoxemia and metabolic acidosis in most of these 11 patients, and presence of shock at arrival in the hospital was noted in 8 patients. Acute renal failure and disseminated intravascular coagulation developed in six patients. Chest radiographs showed pleural effusion and radiographic spread in nearly 50% of patients. Combination chemotherapy consisting of one aminoglycoside and one second- or third-generation cephalosporin was initiated in all patients. The rapidly fatal outcome of these 11 patients with BKPP despite management with adequate antibiotics and intensive care indicated the fulminant nature of this disease. High virulence of the microorganism, altered immune response, and increased susceptibility to infection may all have contributed to the fulminancy in this group of patients. The disease continues to present many difficulties in management.

HIV-1 infection despite immediate combination antiviral therapy after infusion of contaminated white cells

We present a sixth human case in which primary human immunodeficiency virus (HIV-1) infection occurred, despite antiretroviral prophylaxis, after accidental inoculation of infected blood. In the prior five instances, variables such as large virus dose, late administration of antivirals, viral resistance to zidovudine, and pre-existent immunosuppression, may have played a role in the treatment failure. In this case, high-dosage oral zidovudine was given within minutes of the accident and replaced 2 1/2 days later with interferon alpha and dideoxyinosine (ddl). Despite aggressive treatment, HIV-1 infection was demonstrated in blood, spleen, and brain tissue at autopsy 16 days later. Of the tissues studied, detection of HIV-1 was most prominent in the spleen. Double-label immunocytochemistry confirmed the morphologic impression that while some of the infected spleen cells were CD3-positive T cells, the majority were macrophages. Thus, current single or dual (zidovudine, ddl-interferon) therapies for accidental HIV-1 inoculation may not be effective in preventing early infection. Further trials in animals appear warranted to evaluate protection by other strategies, such as passive immunity or combinations of agents that penetrate the brain and attack HIV-1 viral replication at differing sites.

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.

Effect of maternal ethanol consumption on in vitro tumor necrosis factor, interleukin-6 and interleukin-2 production by rat milk and blood leukocytes

It has been shown that the transfer of immunity via lactation plays an important role in providing early protection to the neonate. Maternal ethanol consumption also results in a reduced transfer of immunity to their neonates against a Trichinella spiralis infection. Because of the known presence of cytokines in milk and their important role in inflammation, we tested the effects of maternal ethanol consumption on cytokine production by milk and blood cells from T. spiralis-infected rats. With T. spiralis antigen, Concanavalin A (Con A) or lipopolysaccharide stimulation, milk cells from both ethanol-treated and pair-fed groups were capable of producing tumor necrosis factor (TNF), interleukin (IL)-6 and IL-2. There were no differences between groups for TNF or IL-6 production by milk cells. Milk cells from the ethanol group produced a significantly higher amount of IL-2 upon Con A stimulation, as compared with that from the pair-fed group (16 +/- 4 units/10(6) cells vs. 4 +/- 1 units/10(6) cells, p < 0.05). After stimulation with Con A, blood cells from the ethanol group produced significantly lower amounts of TNF (17 +/- 15 units/10(6) cells) than that from the pair-fed group (102 +/- 64 units/10(6) cells, p < 0.05). The amount of TNF and IL-6 produced by milk cells was significantly lower, as compared with that produced by blood cells. This study suggests that ethanol consumption has some modulatory effects on cytokine production by milk and blood cells.

Ethanol, immune responses, and murine AIDS: the role of vitamin E as an immunostimulant and antioxidant

Excessive alcohol consumption is a major health problem in the United States. Prolonged consumption of alcohol results in alterations of immune responses, ultimately manifested by increasing susceptibility to infectious agents. Such changes can be due to the direct effects of alcohol or its metabolites on immune cells, as well as to nutritional deficiency, oxidative stress, and neutrophil dysfunctions. This ETOH-induced immunosuppression could be a potential cofactor in the progression to AIDS. As vitamin E supplementation has been associated with enhancement of immune response and improvement of host defense, it may provide a useful therapeutic approach for treatment of alcoholics to improve host defense. This article is a review of alcohol-related immunosuppression as a possible cofactor in the development of AIDS, and vitamin E-related immunoenhancing roles in animals and humans, showing why vitamin E supplementation could be used as a useful adjunct agent in alcoholics' treatment. Since there is little information available regarding nutritional therapy with alcohol users, our purpose is to provide evidence from animal models of the potential therapeutic role of vitamin E supplementation in the treatment of alcoholics.

Influence of chronic dietary ethanol on cytokine production by murine splenocytes and thymocytes

Prolonged consumption of ethanol (ETOH) results in alterations of host defense via immune modulation, increasing susceptibility to infection. In the present study, effects of chronic dietary ETOH on cytokine production by splenocytes and thymocytes, splenocyte and thymocyte proliferation induced by mitogens, splenic natural killer cell activity, and antibody production (IgA and IgG) were examined. C57BL/6 mice were fed 5% ETOH v/v in the Lieber-DeCarli liquid diet for 11 weeks. Release of interleukin (IL)-2, IL-5, IL-6, IL-10, and interferon (IFN)-gamma produced by concanavalin A (Con A) stimulated splenocytes was significantly decreased, whereas secretion of IL-4 was slightly decreased by chronic dietary ETOH compared with controls. Production of tumor necrosis factor-alpha and IL-6 by lipopolysaccharide-stimulated splenocytes was significantly and slightly decreased by ETOH compared with controls, respectively. Splenocyte and thymocyte proliferation induced by Con A was significantly inhibited by ETOH, whereas splenocyte proliferation induced by lipopolysaccharide was not affected. Natural killer cell activity was significantly inhibited by ETOH compared with controls. The production of IgA and IgG by splenocytes were also significantly decreased by ETOH compared with controls. The levels of IL-2, IL-4, and IL-6 produced by Con A-stimulated thymocytes were significantly reduced by dietary ETOH compared with control, whereas production of IFN-gamma by thymocytes was not affected. Our results suggest that chronic dietary ETOH alters the cytokine release, thereby impairing immune response and T-cell maturation, which increase host susceptibility to infection.

Ethanol-specific impairment of T-lymphocyte activation is caused by a transitory block in signal-transduction pathways

BACKGROUND

Immune system derangement is characteristic of alcoholic liver cirrhosis. However, in vitro studies have never clarified the alcohol-induced T-lymphocyte dysfunction. The aim of this study was to examine any discrete phenotypical and functional abnormalities and possible impairment in transmembrane signal-transduction pathways that, if present on lymphocytes of patients with alcoholic cirrhosis, would also be reproducible after in vitro ethanol exposure of normal T cells.

METHODS

Lymphocytes from 25 patients were analyzed for their in vitro proliferative functions, intracellular Ca2+ fluxes, and inositol 1,4,5-triphosphate (IP3) generation. The same procedures were applied to normal T cells exposed in vitro to ethanol.

RESULTS

Lymphocytes failed to respond to anti-CD3 and anti-CD2 after in vitro stimulation, with decreased intracellular Ca2+ mobilization and IP3 generation but showed normal proliferative response to phytohemagglutinin. In vitro ethanol incubation of normal T lymphocytes resulted in rearrangement of the membrane CD45 antigen, favoring the expression of high-molecular-weight isoforms, and showed a poor blastogenic response to anti-CD3 and anti-CD2 with a decrease in intracellular Ca2+ mobilization and IP3 production. After a 6-month period of ethanol withdrawal, some patients had normalization of phenotypic and functional alterations.

CONCLUSIONS

The T-lymphocyte response to specific polyclonal activators may be severely impaired in alcohol abusers. However, it seems reversible after a period of controlled ethanol withdrawal.

Immune function in alcoholism: a controlled study

Several studies have shown an increased risk for infection and cancer in alcoholic patients. The mechanisms for such observations remain largely unknown. In an effort to investigate the possibility of immunological dysfunction in alcoholism, we studied three immune parameters in 47 hospitalized chronic alcoholic patients and 47 age- and sex-matched normal controls. The immune measures were: (1) lymphocyte phenotyping, with estimates of percentages of T cells, B cells, T helpers, T suppressors, natural killer (NK) cells, and cells carrying the activation markers IL2R1 and I2; (2) NK cell activity; and (3) lymphokine-activated killer cell activity. Results indicate a significant increase in the IL2R and I2 lymphocyte markers in alcoholic patients compared with matched controls. We also found a nonsignificant trend for a decrease in the percentage of suppressor T cells in the alcoholic group, as well as a trend for a negative correlation between the percentage of T suppressor cells and age. There were no significant differences in either NK or lymphokine-activated killer cell activities between the two groups. Furthermore, there were no significant associations between duration and intensity of alcohol consumption and any of the immune measures. These results suggest subtle alterations in immune regulation in alcoholic patients that cannot be explained solely on the basis of duration and/or amount of alcohol consumed.