Chronic ethanol induces inhibition of antigen-specific CD8+ but not CD4+ immunodominant T cell responses following Listeria monocytogenes inoculation

Effects of prenatal alcohol exposure on infant lung function, wheeze, and respiratory infections in Australian children

BACKGROUND

Prenatal alcohol exposure (PAE) is a known risk factor for a range of adverse outcomes, such as facial dysmorphism, adverse birth outcomes, and neurodevelopmental changes. Preclinical research shows that PAE also inhibits lung development, lowers surfactant protein expression, has detrimental effects on alveolar macrophages, and decreases both T and B cell numbers. However, clinical evidence of respiratory impacts from PAE is limited. This study explored whether lung function, wheeze, and incidence of respiratory infections differ in children with PAE compared with unexposed children.

METHODS

Data from the Barwon Infant Study (n = 1074) were examined. PAE data were extracted from maternal questionnaires at trimesters 1 and 2 (combined), and trimester 3, and included as "total standard drinks" during each trimester and total pregnancy intake, a binary yes/no for PAE, and binge drinking (>5 standard drinks in one session). Respiratory outcomes were parent-reported wheeze, lung function (measured by multiple breath washout), and parent report and medical record indicators of health service attendances for respiratory conditions. Linear and logistic regressions were performed to quantify relationships between PAE and respiratory outcomes, controlling for socioeconomic status, birthweight, sex, gestational age, and maternal smoking.

RESULTS

Binge drinking was associated with increased health service attendance for respiratory condition(s) in the first 12 months of life (OR = 5.0, 95% CI (1.7, 20.7), p = 0.008). We did not find a relationship between binary PAE and binge drinking with lung function at 4 weeks of age or wheeze at 12 months. The number of standard drinks consumed in trimester two was associated with a lower lung clearance index (β = -0.011 turnovers, 95% CI (-0.0200, -0.0013), p = 0.03), and a small increase in functional residual capacity (β = 0.34 mL, 95% CI (0.02, 0.66), p = 0.04).

CONCLUSIONS

We found an association between binge drinking and health service utilization for respiratory conditions in infancy, but no evidence that low-level PAE was associated with adverse respiratory outcomes.

A Potential Protective Effect of Alcohol Consumption in Male Genital Lichen Sclerosus: A Case-Control Study

Introduction and Objectives. Lichen sclerosus (LSc) is a chronic inflammatory process of the skin characterized by its unique histological features. It affects men and women of all ages, mainly in the anogenital area. The etiologies and exact pathophysiology are not well-known; however, LSc can be considered a precursor to male genital squamous cell carcinoma. We aim, through this case-control study, to potentially associate genital LSc with risk factors and certain patient characteristics in Lebanese adult males. Materials and Methods. A nested case-control study design was chosen. Subjects enrolled were adult male patients who had a circumcision between January 2010 and December 2020 at our university hospital, with a confirmed LSc diagnosis on pathology. Cases were matched with controls by age with a ratio of 1 : 1, all of whom were circumcised and had a negative pathology report. Data collection consisted of sociodemographic, behavioral, and past medical and familial history characteristics. Results. A total of 94 patients were enrolled. The mean age was 49.81 (±22.92) in the group of men with LSc. No significant differences in sociodemographic characteristics (age and BMI) were found between the two compared groups. Smoking cannot predict LSc as opposed to alcohol consumption, which we found to be a protective factor against the appearance of LSc ( $p=0.027$ ). Men with LSc had significantly higher rates of diabetes ( $p=0.021$ ) and hypertension ( $p=0.004$ ). No associations were found between LSc and the presenting chief complaints, family history of LSc, and past penile trauma. Conclusion. In this study, we were able to compare multiple variables between 47 circumcised patients diagnosed with LSc and a control group. We found that LSc patients showed higher rates of diabetes and hypertension. A potential protective effect of alcohol consumption is to be explored in future projects with bigger sample sizes and higher statistical powers.

Impact of alcohol consumption on coronavirus disease 2019 severity: A systematic review and meta-analysis

Fear and misinformation lead to widespread myths in the coronavirus disease 2019 (COVID-19) pandemic, such as "consuming high-strength alcohol kills the virus in the inhaled air." However, whether alcohol consumption can affect COVID-19 has not been clarified yet. This study aims to investigate the impact of alcohol consumption on COVID-19 severity. PubMed, Embase, Cochrane Library, Central, CINAHL, ClinicalTrials.gov, and WHO-International Clinical Trials Registry Platform were searched until November 25, 2022. Forty studies (1,697,683 COVID-19 individuals) were analyzed. Brown (patients numbers: 1317, risk ratios [RR] = 1.58, 95% [confidence interval] CI = 1.31 to 1.90, I2  = 0.0%, p < 0.001), American (patients numbers: 3721, RR = 1.51, 95% CI = 1.30 to 1.75, I2  = 0.0%, p < 0.001), and European (patients numbers: 261,437, RR = 2.04, 95% CI = 1.96 to 2.13, I2  = 0.0%, p < 0.001) drinkers were at high risk of severe COVID-19, intensive care unit (ICU) admission, and invasive mechanical ventilation (IMV), respectively. Consistently, individuals with a drinking history were at high risk of severe COVID-19 (patients numbers: 5399, RR = 1.23, 95% CI = 1.02 to 1.48, I2  = 38.4%, p = 0.03) and ICU admission (patients numbers: 6995, RR = 1.32, 95% CI = 1.08 to 1.60, I2  = 46.6%, p = 0.01). In addition, current drinkers had an increased risk of symptomatic COVID-19. However, excessive drinkers were at high risk of COVID-19 hospitalization. Alcohol consumption intensifies COVID-19 severity and deteriorates its clinical outcomes. Here, we strongly propose that people do not drink alcohol during the COVID-19 pandemic.

Pathogenesis of Alcohol-Associated Liver Disease

Excessive alcohol consumption is a global healthcare problem with enormous social, economic, and clinical consequences. While chronic, heavy alcohol consumption causes structural damage and/or disrupts normal organ function in virtually every tissue of the body, the liver sustains the greatest damage. This is primarily because the liver is the first to see alcohol absorbed from the gastrointestinal tract via the portal circulation and second, because the liver is the principal site of ethanol metabolism. Alcohol-induced damage remains one of the most prevalent disorders of the liver and a leading cause of death or transplantation from liver disease. Despite extensive research on the pathophysiology of this disease, there are still no targeted therapies available. Given the multifactorial mechanisms for alcohol-associated liver disease pathogenesis, it is conceivable that a multitherapeutic regimen is needed to treat different stages in the spectrum of this disease.

Alcohol Impairs Immunometabolism and Promotes Naïve T Cell Differentiation to Pro-Inflammatory Th1 CD4+ T Cells

CD4+ T cell differentiation to pro-inflammatory and immunosuppressive subsets depends on immunometabolism. Pro-inflammatory CD4+ subsets rely on glycolysis, while immunosuppressive Treg cells require functional mitochondria for their differentiation and function. Previous pre-clinical studies have shown that ethanol (EtOH) administration increases pro-inflammatory CD4+ T cell subsets; whether this shift in immunophenotype is linked to alterations in CD4+ T cell metabolism had not been previously examined. The objective of this study was to determine whether ethanol alters CD4+ immunometabolism, and whether this affects CD4+ T cell differentiation. Naïve human CD4+ T cells were plated on anti-CD3 coated plates with soluble anti-CD28, and differentiated with IL-12 in the presence of ethanol (0 and 50 mM) for 3 days. Both Tbet-expressing (Th1) and FOXP3-expressing (Treg) CD4+ T cells increased after differentiation. Ethanol dysregulated CD4+ T cell differentiation by increasing Th1 and decreasing Treg CD4+ T cell subsets. Ethanol increased glycolysis and impaired oxidative phosphorylation in differentiated CD4+ T cells. Moreover, the glycolytic inhibitor 2-deoxyglucose (2-DG) prevented the ethanol-mediated increase in Tbet-expressing CD4+ T cells but did not attenuate the decrease in FOXP3 expression in differentiated CD4+ T cells. Ethanol increased Treg mitochondrial volume and altered expression of genes implicated in mitophagy and autophagosome formation (PINK1 and ATG7). These results suggest that ethanol impairs CD4+ T cell immunometabolism and disrupts mitochondrial repair processes as it promotes CD4+ T cell differentiation to a pro-inflammatory phenotype.

Alcohol as friend or foe in autoimmune diseases: a role for gut microbiome?

Alcohol is well known for promoting systemic inflammation and aggravating multiple chronic health conditions. Thus, alcohol may also be expected to serve as a risk factor in autoimmune diseases. However, emerging data from human and animal studies suggest that alcohol may in fact be protective in autoimmune diseases. These studies point toward alcohol's complex dose-dependent relationship in autoimmune diseases as well as potential modulation by duration and type of alcohol consumption, cultural background and sex. In this review, we will explore alcohol's pro- and anti-inflammatory properties in human and animal autoimmune diseases, including autoimmune diabetes, thyroid disease, systemic lupus erythematosus, rheumatoid arthritis, experimental autoimmune encephalomyelitis and multiple sclerosis. We will also discuss potential mechanisms of alcohol's anti-inflammatory effects mediated by the gut microbiome.

Chronic ethanol consumption compromises neutrophil function in acute pulmonary Aspergillus fumigatus infection

Chronic ethanol consumption is a leading cause of mortality worldwide, with higher risks to develop pulmonary infections, including Aspergillus infections. Mechanisms underlying increased susceptibility to infections are poorly understood. Chronic ethanol consumption induced increased mortality rates, higher Aspergillus fumigatus burden and reduced neutrophil recruitment into the airways. Intravital microscopy showed decrease in leukocyte adhesion and rolling after ethanol consumption. Moreover, downregulated neutrophil activation and increased levels of serum CXCL1 in ethanol-fed mice induced internalization of CXCR2 receptor in circulating neutrophils. Bone marrow-derived neutrophils from ethanol-fed mice showed lower fungal clearance and defective reactive oxygen species production. Taken together, results showed that ethanol affects activation, recruitment, phagocytosis and killing functions of neutrophils, causing susceptibility to pulmonary A. fumigatus infection. This study establishes a new paradigm in innate immune response in chronic ethanol consumers.

Alcoholism is a chronic disease that has many damaging effects on the body. Over long periods, excessive alcohol intake weakens the immune system, putting consumers at increased risk of getting lung infections such as pneumonia.

Some forms of pneumonia can be caused by the fungus Aspergillus fumigatus. This microbe does not tend to be a problem for healthy individuals, but it can be fatal for those with impaired immune systems. Here, Malacco et al. wanted to find out why excessive alcohol consumers are more prone to pneumonia.

To test this, the researchers used two groups of mice that were either fed plain water or water containing ethanol. After 12 weeks, both groups were infected with Aspergillus fumigatus. The results showed that alcohol-fed mice were more susceptible to the infection caused by strong inflammation of the lungs.

Normally, the immune system confronts a lung infection by activating a group of defense cells called neutrophils, which travel through the blood system to the infection site. Once in the right spot, neutrophils get to work by releasing toxins that kill the fungus. Malacco et al. discovered that after chronic alcohol consumption, neutrophils were less reactive to inflammatory signals and less likely to reach the lungs. They were also less effective in dealing with the infection. Neutrophil released fewer toxins and were thus less able to kill the microbial cells.

These findings demonstrate for the first time how alcohol can affect immune cells during infection and pave the way for new possibilities to prevent fatal lung infections in excessive alcohol consumers. A next step would be to identify how alcohol acts on other processes in the body and to find a way to modulate or even revert the changes it causes.

Chronic Ethanol Consumption Reduces Existing CD8 T Cell Memory and Is Associated with Lesions in Protection against Secondary Influenza A Virus Infections

Chronic alcohol consumption is associated with an increased incidence of disease severity during pulmonary infections. Our previous work in a mouse model of chronic alcohol consumption has detailed that the primary influenza A virus (IAV)-specific CD8 T cell response in mice that consumed ethanol (EtOH) had a reduced proliferative capacity as well as the ability to kill IAV target cells. Interestingly, recent studies have highlighted that human alcoholics have an increased susceptibility to IAV infections, even though they likely possess pre-existing immunity to IAV. However, the effects of chronic alcohol consumption on pre-existing immune responses (i.e., memory) to IAV have not been explored. Our results presented in this study show that IAV-immune mice that then chronically consumed alcohol (X31→EtOH) exhibited increased morbidity and mortality following IAV re-exposure compared with IAV-immune mice that had consumed water (X31→H₂O). This increased susceptibility in X31→EtOH mice was associated with reduced IAV-specific killing of target cells and a reduction in the number of IAV-specific CD8 T cells within the lungs. Furthermore, upon IAV challenge, recruitment of the remaining memory IAV-specific CD8 T cells into the lungs is reduced in X31→EtOH mice. This altered recruitment is associated with a reduced pulmonary expression of CXCL10 and CXCL11, which are chemokines that are important for T cell recruitment to the lungs. Overall, these results demonstrate that chronic alcohol consumption negatively affects the resting memory CD8 T cell response and reduces the ability of memory T cells to be recruited to the site of infection upon subsequent exposures, therein contributing to an enhanced susceptibility to IAV infections.

Dose-dependent effects of chronic alcohol drinking on peripheral immune responses

It is well established that chronic heavy alcohol drinking (CHD) results in significant organ damage, increased susceptibility to infections, and poor outcomes following injury. In contrast, chronic moderate drinking (CMD) has been associated with improved cardiovascular health and immunity. These differential outcomes have been linked to alterations in both innate and adaptive branches of the immune system; however, the mechanisms remain poorly understood. To address this question, we determined the impact of chronic drinking on the transcriptional and functional responses of peripheral blood mononuclear cells (PBMC) collected from male rhesus macaques classified as CMD or CHD after 12 months of voluntary ethanol self-administration. Our analysis suggests that chronic alcohol drinking, regardless of dose alters resting transcriptomes of PBMC, with the largest impact seen in innate immune cells. These transcriptional changes are partially explained by alterations in microRNA profiles. Additionally, chronic alcohol drinking is associated with a dose dependent heightened inflammatory profiled at resting and following LPS stimulation. Moreover, we observed a dose-dependent shift in the kinetics of transcriptional responses to LPS. These findings may explain the dichotomy in clinical and immunological outcomes observed with moderate versus heavy alcohol drinking.

Chronic alcohol consumption exacerbates murine cytomegalovirus infection via impairing nonspecific and specific NK activation in mice

Chronic alcohol consumption increases the susceptibility to infectious diseases by compromising immune system. Cytomegalovirus infection is common in human and usually is asymptomatic in immunocompetent people. However, it can induce life-threatening medical complications in immunocompromised individuals such as alcoholics. How chronic alcohol consumption exacerbates cytomegalovirus infection is not known. Herein, we used a mouse cytomegalovirus model to study the underlying cellular and molecular mechanism. We found that alcohol consumption increased viral titers in spleen after 4 days of infection, enhanced body weight loss and inhibited splenomegaly during the acute phase of infection. Blood level of IFN-β, splenic IFN-γ and granzyme B-producing NK cells were lower in alcohol-consuming mice than in water-drinking mice at 12 h after viral infection. Moreover, alcohol consumption decreased IL-15-producing DC after 36 h infection, inhibited NK cell, specifically Ly49H⁺ NK cell maturation and proliferation 3-6 days after viral infection. Surprisingly, alcohol consumption enhanced NK cell and CD8⁺ T cell continuous activation and increased granzyme B-producing cells. However, alcohol consumption decreased the expression of perforin in spleen and liver. Taken together, chronic alcohol consumption exacerbates cytomegalovirus infection via impairing non-specific and specific NK cell activation, specifically IFN-γ and perforin production.

Chronic alcohol consumption exacerbates murine cytomegalovirus infection via impairing nonspecific and specific NK activation in mice

Chronic alcohol consumption increases the susceptibility to infectious diseases by compromising the immune system. Cytomegalovirus infection is common in humans and usually is asymptomatic in immunocompetent people. However, it can induce life‐threatening medical complications in immunocompromised individuals such as alcoholics. How chronic alcohol consumption exacerbates cytomegalovirus infection is not known. Herein, we used a mouse cytomegalovirus model to study the underlying cellular and molecular mechanism. We found that alcohol consumption increased viral titers in spleen after 4 days of infection, enhanced body weight loss and inhibited splenomegaly during the acute phase of infection. Blood level of IFN‐β, splenic IFN‐γ and granzyme B‐producing NK cells were lower in alcohol‐consuming mice than in water‐drinking mice at 12 hours after viral infection. Moreover, alcohol consumption decreased IL‐15‐producing DC after 36 hours infection, inhibited NK cell, specifically Ly49H⁺ NK cell maturation and proliferation 3‐6 days after viral infection. Surprisingly, alcohol consumption enhanced NK cell and CD8⁺ T‐cell continuous activation and increased granzyme B‐producing cells. However, alcohol consumption decreased the expression of perforin in spleen and liver. Taken together, chronic alcohol consumption exacerbates cytomegalovirus infection via impairing nonspecific and specific NK cell activation, specifically IFN‐γ and perforin production.

Ethanol-Induced Alterations of T Cells and Cytokines after Surgery in a Murine Infection Model

Background

Interactions between alcohol, infection, and surgery and their effect on differentiation and functionality of T helper cells are not yet completely understood. We hypothesized that alcohol and surgery disturb differentiation of T helper cells and contribute to an impaired immune response.

Methods

Mice were treated with alcohol for two weeks. Saline treatment served as control. Clinical performance and weight were assessed. On day 14, a median laparotomy was performed and animals were challenged with Klebsiella pneumoniae intranasally. Bacterial load was determined in lungs and blood. T helper cell subpopulations and the released cytokines were assessed in lungs, spleens, and plasma. Key transcription factors of T cell differentiation were evaluated.

Results

Alcohol significantly impaired clinical appearance and body weight of animals with postsurgical infection (p < 0.05). Bacterial load was significantly higher after alcohol treatment (p < 0.05). T helper cell subsets and released cytokine levels were significantly altered in lung, but not in spleen. Expression of transcription factors of T helper cell lineage commitment did not translate into different counts of T helper cells.

Conclusions

Alcohol and surgery lead to significant cellular and functional modulations of T helper cells during postsurgical infection. These effects may contribute to an impaired immune response after surgery.

Opposing effects of alcohol on the immune system

Several studies have described a dose-dependent effect of alcohol on human health with light to moderate drinkers having a lower risk of all-cause mortality than abstainers, while heavy drinkers are at the highest risk. In the case of the immune system, moderate alcohol consumption is associated with reduced inflammation and improved responses to vaccination, while chronic heavy drinking is associated with a decreased frequency of lymphocytes and increased risk of both bacterial and viral infections. However, the mechanisms by which alcohol exerts a dose-dependent effect on the immune system remain poorly understood due to a lack of systematic studies that examine the effect of multiple doses and different time courses. This review will summarize our current understanding of the impact of moderate versus excessive alcohol consumption on the innate and adaptive branches of the immune system derived from both in vitro as well as in vivo studies carried out in humans and animal model studies.

Alcohol Consumption Modulates Host Defense in Rhesus Macaques by Altering Gene Expression in Circulating Leukocytes

Several lines of evidence indicate that chronic alcohol use disorder leads to increased susceptibility to several viral and bacterial infections, whereas moderate alcohol consumption decreases the incidence of colds and improves immune responses to some pathogens. In line with these observations, we recently showed that heavy ethanol intake (average blood ethanol concentrations > 80 mg/dl) suppressed, whereas moderate alcohol consumption (blood ethanol concentrations < 50 mg/dl) enhanced, T and B cell responses to modified vaccinia Ankara vaccination in a nonhuman primate model of voluntary ethanol consumption. To uncover the molecular basis for impaired immunity with heavy alcohol consumption and enhanced immune response with moderate alcohol consumption, we performed a transcriptome analysis using PBMCs isolated on day 7 post-modified vaccinia Ankara vaccination, the earliest time point at which we detected differences in T cell and Ab responses. Overall, chronic heavy alcohol consumption reduced the expression of immune genes involved in response to infection and wound healing and increased the expression of genes associated with the development of lung inflammatory disease and cancer. In contrast, chronic moderate alcohol consumption upregulated the expression of genes involved in immune response and reduced the expression of genes involved in cancer. To uncover mechanisms underlying the alterations in PBMC transcriptomes, we profiled the expression of microRNAs within the same samples. Chronic heavy ethanol consumption altered the levels of several microRNAs involved in cancer and immunity and known to regulate the expression of mRNAs differentially expressed in our data set.

Chronic Ethanol Exposure: Pathogenesis of Pulmonary Disease and Dysfunction

Ethanol (EtOH) is the world’s most commonly used drug, and has been widely recognized as a risk factor for developing lung disorders. Chronic EtOH exposure affects all of the organ systems in the body and increases the risk of developing pulmonary diseases such as acute lung injury and pneumonia, while exacerbating the symptoms and resulting in increased mortality in many other lung disorders. EtOH and its metabolites inhibit the immune response of alveolar macrophages (AMs), increase airway leakage, produce damaging reactive oxygen species (ROS), and disrupt the balance of antioxidants/oxidants within the lungs. In this article, we review the role of EtOH exposure in the pathogenesis and progression of pulmonary disease.

Chronic ethanol feeding increases the severity of Staphylococcus aureus skin infections by altering local host defenses

Alcoholics are at increased risk of Staphylococcus aureus skin infection and serious sequelae, such as bacteremia and death. Despite the association between alcoholism and severe S. aureus skin infection, the impact of EtOH on anti-S. aureus cutaneous immunity has not been investigated in a model of chronic EtOH exposure. To test the hypothesis that EtOH enhances the severity of S. aureus skin infection, mice were fed EtOH for ≥12 weeks via the Meadows-Cook model of alcoholism and inoculated with S. aureus following epidermal abrasion. Evidence of exacerbated staphylococcal disease in EtOH-fed mice included: skin lesions that were larger and contained more organisms, greater weight loss, and increased bacterial dissemination. Infected EtOH-fed mice demonstrated poor maintenance and induction of PMN responses in skin and draining LNs, respectively. Additionally, altered PMN dynamics in the skin of these mice corresponded with reduced production of IL-23 and IL-1β by CD11b(+) myeloid cells and IL-17 production by γδ T cells, with the latter defect occurring in the draining LNs as well. In addition, IL-17 restoration attenuated S. aureus-induced dermatopathology and improved bacterial clearance defects in EtOH-fed mice. Taken together, the findings show, in a novel model system, that the EtOH-induced increase in S. aureus-related injury/illness corresponds with defects in the IL-23/IL-17 inflammatory axis and poor PMN accumulation at the site of infection and draining LNs. These findings offer new information about the impact of EtOH on cutaneous host-defense pathways and provide a potential mechanism explaining why alcoholics are predisposed to S. aureus skin infection.

Prenatal Alcohol Exposure and the Developing Immune System

Evidence from research in humans and animals suggest that ingesting alcohol during pregnancy can disrupt the fetal immune system and result in an increased risk of infections and disease in newborns that may persist throughout life. Alcohol may have indirect effects on the immune system by increasing the risk of premature birth, which itself is a risk factor for immune-related problems. Animal studies suggest that alcohol exposure directly disrupts the developing immune system. A comprehensive knowledge of the mechanisms underlying alcohol's effects on the developing immune system only will become clear once researchers establish improved methods for identifying newborns exposed to alcohol in utero.

Impact of Alcohol Abuse on the Adaptive Immune System

Alcohol exposure, and particularly chronic heavy drinking, affects all components of the adaptive immune system. Studies both in humans and in animal models determined that chronic alcohol abuse reduces the number of peripheral T cells, disrupts the balance between different T-cell types, influences T-cell activation, impairs T-cell functioning, and promotes T-cell apoptosis. Chronic alcohol exposure also seems to cause loss of peripheral B cells, while simultaneously inducing increased production of immunoglobulins. In particular, the levels of antibodies against liver-specific autoantigens are increased in patients with alcoholic liver disease and may promote alcohol-related liver damage. Finally, chronic alcohol exposure in utero interferes with normal T-cell and B-cell development, which may increase the risk of infections during both childhood and adulthood. Alcohol's impact on T cells and B cells increases the risk of infections (e.g., pneumonia, HIV infection, hepatitis C virus infection, and tuberculosis), impairs responses to vaccinations against such infections, exacerbates cancer risk, and interferes with delayed-type hypersensitivity. In contrast to these deleterious effects of heavy alcohol exposure, moderate alcohol consumption may have beneficial effects on the adaptive immune system, including improved responses to vaccination and infection. The molecular mechanisms underlying ethanol's impact on the adaptive immune system remain poorly understood.

Chronic ethanol exposure selectively inhibits the influenza-specific CD8 T cell response during influenza a virus infection

BACKGROUND

It is well established that chronic ethanol (EtOH) consumption is associated with increased incidence and disease severity of respiratory infections. Our recent work demonstrates this increase in disease severity to influenza A virus (IAV) infections is due, in part, to a failure to mount a robust IAV-specific CD8 T cell response along with a specific impairment in the ability of these T cells to produce interferon γ (IFNγ). However, the full extent of the lesion in the effector CD8 T cell compartment during chronic EtOH consumption remains unknown.

METHODS

Utilizing the Meadows-Cook murine model of chronic alcohol consumption, mice received EtOH in their drinking water for 8 or 12 weeks. Mice were challenged intranasally with IAV, and the activation and effector functions of IAV-specific CD8 T cells were determined in both the lung-draining lymph nodes (dLN) and lungs.

RESULTS

Our results confirm the defect in IFNγ production; however, the ability of IAV-specific T cells to produce tumor necrosis factor α (TNFα) and interleukin-2 (IL-2) in EtOH-consuming mice remains unaltered. In contrast, EtOH consumption significantly reduces the ability of CD8 T cells to degranulate and kill IAV-specific targets. Finally, our findings suggest the lesion begins during the initial activation of CD8 T cells, as we observe early defects in proliferation in the dLN of IAV-infected, EtOH-consuming mice.

CONCLUSIONS

These findings highlight the previously unrecognized depth of the lesion in the IAV-specific CD8 T cell response during chronic EtOH consumption. Given the important role CD8 T cell immunity plays in control of IAV, these findings may aid in the development of vaccination and/or therapeutic strategies to reverse these defects in the CD8 T cell response and reduce serious disease outcomes associated with IAV infections in alcoholics.

Chronic ethanol consumption modulates growth factor release, mucosal cytokine production, and microRNA expression in nonhuman primates

BACKGROUND

Chronic alcohol consumption has been associated with enhanced susceptibility to both systemic and mucosal infections. However, the exact mechanisms underlying this enhanced susceptibility remain incompletely understood.

METHODS

Using a nonhuman primate model of ethanol (EtOH) self-administration, we examined the impact of chronic alcohol exposure on immune homeostasis, cytokine, and growth factor production in peripheral blood, lung, and intestinal mucosa following 12 months of chronic EtOH exposure.

RESULTS

EtOH exposure inhibited activation-induced production of growth factors hepatocyte growth factor (HGF), granulocyte colony-stimulating factor (G-CSF), and vascular-endothelial growth factor (VEGF) by peripheral blood mononuclear cells (PBMC). Moreover, EtOH significantly reduced the frequency of colonic Th1 and Th17 cells in a dose-dependent manner. In contrast, we did not observe differences in lymphocyte frequency or soluble factor production in the lung of EtOH-consuming animals. To uncover mechanisms underlying reduced growth factor and Th1/Th17 cytokine production, we compared expression levels of microRNAs in PBMC and intestinal mucosa. Our analysis revealed EtOH-dependent up-regulation of distinct microRNAs in affected tissues (miR-181a and miR-221 in PBMC; miR-155 in colon). Moreover, we were able to detect reduced expression of the transcription factors STAT3 and ARNT, which regulate expression of VEGF, G-CSF, and HGF and contain targets for these microRNAs. To confirm and extend these observations, PBMC were transfected with either mimics or antagomirs of miR-181 and miR-221, and protein levels of the transcription factors and growth factors were determined. Transfection of microRNA mimics led to a reduction in both STAT3/ARNT as well as VEGF/HGF/G-CSF levels. The opposite outcome was observed when microRNA antagomirs were transfected.

CONCLUSIONS

Chronic EtOH consumption significantly disrupts both peripheral and mucosal immune homeostasis, and this dysregulation may be mediated by changes in microRNA expression.

Chronic ethanol feeding induces subset loss and hyporesponsiveness in skin T cells

BACKGROUND

Chronic alcoholism is associated with increased incidence and severity of cutaneous infection. Skin-resident T cells orchestrate numerous immunological functions that are critically involved in both tissue homeostasis and cutaneous immunity. The impact of chronic ethanol (EtOH) exposure on skin T cells has not previously been examined; given their important role in maintaining the immune barrier function of the skin further study is warranted.

METHODS

Mice were administered EtOH in the drinking water for 12 to 16 weeks. Flow cytometry was used to evaluate impact of EtOH feeding on skin T cell numbers, rates of proliferation, and apoptosis as well as activation marker expression and cytokine production after ex vivo stimulation.

RESULTS

Chronic EtOH feeding caused a baseline reduction in dendritic epidermal T cell (DETC) numbers that corresponded with reduced expression of the activation marker JAML following phorbol 12-myristate 13-acetate (PMA)/ionomycin stimulation. Chronic EtOH feeding did not alter total numbers of dermal T cells, but specific subset loss was observed in Foxp3(+) regulatory T cells (Tregs) as well as CD3hi, Vγ3(+) and CD3int, Vγ3(-) dermal γδ T cells. EtOH-induced dysfunction in the latter population, which represents prototypical interleukin-17 (IL-17)-producing dermal γδT17s, was made evident by diminished IL-17 production following anti-CD3 stimulation. Additionally, the capacity of lymph node γδ T cells to produce IL-17 following anti-CD3 and PMA/ionomycin stimulation was impaired by chronic EtOH feeding.

CONCLUSIONS

Chronic EtOH feeding induced defects in both numbers and function of multiple skin T cell subsets. The decreased density and poor responsiveness of DETCs and γδT17 cells in particular would be expected to compromise immune effector mechanisms necessary to maintain a protective barrier and restrict pathogen invasion. These findings demonstrate the sensitivity of skin T cells to EtOH and provide new mechanisms to help explain the propensity of alcoholics to suffer skin infection.

Moderate alcohol consumption enhances vaccine-induced responses in rhesus macaques

We have recently shown that chronic alcohol consumption in a rhesus macaque model of ethanol self-administration significantly modulates the serum cytokine profile. In this study, we extended these observations by investigating the impact of chronic ethanol exposure on the immune response to Modified Vaccinia Ankara (MVA). All animals were vaccinated with MVA before ethanol exposure to ethanol and then again after 7 months of 22 h/day of "open-access" drinking of 4% (w/v) ethanol. Our results indicate that animals whose blood ethanol concentration (BEC) chronically exceeded 80 mg/dl had lower CD4 and CD8 T cell proliferation as well as IgG responses following MVA booster than control animals. In contrast, relatively moderate drinkers whose BEC remained below 80 mg/ml exhibited more robust MVA-specific IgG and CD8 T cell responses than controls. To begin to uncover mechanisms underlying the differences in MVA-specific responses between the three groups, we analyzed plasma cytokine levels and microRNA expression in peripheral blood mononuclear cells following MVA booster. Our findings suggest that moderate ethanol consumption results in higher levels of antiviral cytokines and an expression profile of microRNAs linked to CD8 T cell differentiation. In summary, moderate alcohol consumption enhances recall vaccine responses, whereas chronic alcohol intoxication suppresses this response.

Mechanisms by which chronic ethanol feeding impairs the migratory capacity of cutaneous dendritic cells

BACKGROUND

Chronic alcoholism is associated with increased incidence and severity of skin infection. Cutaneous dendritic cells (CDCs) play a pivotal role in skin immunity, and chronic ethanol (EtOH) feeding in mice has been shown to inhibit CDC migration to skin-draining lymph nodes (dLNs) following epicutaneous sensitization. Because CDC subsets differentially initiate T-cell responses, it is important to determine how EtOH feeding affects migration of each subset and identify mechanisms responsible for observed defects.

METHODS

Mice received EtOH in the drinking water for ≥ 16 weeks. Baseline numbers of CDC subsets and their migration to the dLNs following fluorescein 5-isothiocyanate (FITC) sensitization were assessed by flow cytometry. Epidermal cell suspension and skin explant cultures were used to measure the impact of EtOH upon molecules that influence CDC migration. Cytokine arrays performed on explant culture supernatants assessed local production of inflammatory cytokines.

RESULTS

Chronic EtOH feeding reduced migration of all CDC subsets to the dLNs following FITC sensitization. Reduced migration of dermal-resident CDCs did not correspond with reduced baseline numbers of these cells. For Langerhans cells (LCs), EtOH-induced migratory dysfunction corresponded with delayed down-regulation of E-cadherin, chemokine receptor 1 (CCR1), and CCR6 and impaired up-regulation of matrix metalloproteinases (MMPs) 2 and 9. In skin explant assays, EtOH blunted CDC mobilization following stimulation with CCL21/CPG 1826. No alteration in CD54 or CCR7 expression was observed, but production of skin-derived tumor necrosis factor alpha (TNF-α) was reduced. Poor migratory responses in vitro could be improved by supplementing explant cultures from EtOH-fed mice with TNF-α.

CONCLUSIONS

Chronic EtOH consumption does not alter baseline dermal-resident CDC numbers. However, like LCs, migratory responsiveness of dermal CDCs was decreased following FITC sensitization. Inefficient down-regulation of both CCRs and adhesion molecules and the inability to up-regulate MMPs indicate that EtOH impedes LC acquisition of a promigratory phenotype. These defects, combined with improvement of the migratory defect with in vitro TNF-α replacement, demonstrate intrinsic as well as environmental contributions to defective CDC migration. These findings provide novel mechanisms to explain the observed increased incidence and severity of skin infections in chronic alcoholics.

Functional polymorphisms in FAS and FASL contribute to risk of squamous cell carcinoma of the larynx and hypopharynx in a Chinese population

Accumulating evidences indicate that the functional FAS-1377G>A, -670A>G and FASL-844T>C polymorphisms affect the risk of several kinds of cancers. However, their roles in the development of larynx and hypopharynx squamous cell carcinoma (SCC) were still unknown in the Chinese. In the current study, we examined whether these functional genetic variants were associated with the risk of larynx and hypopharynx squamous SCC in a Han Chinese population. The FAS and FASL polymorphisms were genotyped in 300 patients with laryngeal and hypopharyngeal SCC and 300 control subjects by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). Logistic regression analysis revealed that subjects carrying the FASL-844CT or TT genotype had a significantly decreased risk of developing laryngeal and hypopharyngeal SCC [odds ratio (OR)=0.69; 95% confidence interval (CI)=0.51-0.93; P=0.016; or, OR=0.41; 95% CI=0.20-0.86; P=0.009] compared with those carrying the CC genotype. Joint gene-smoking and gene-drinking effects were also observed, with the OR of CC genotype for smokers or drinkers were 5.15 (95%CI=3.24-8.97) or 12.52 (95%CI=7.31-22.47), respectively. Therefore, the FASL-844T>C polymorphism is associated with genetic susceptibility of developing laryngeal and hypopharyngeal SCC in a Han Chinese population.

Perinatal exposure to alcohol: implications for lung development and disease

In utero alcohol exposure dramatically increases the risk of premature delivery. However, the majority of premature and term newborns exposed to alcohol remain undetected by medical caregivers. There is a desperate need for reliable and accurate biomarkers of alcohol exposure for the term and premature newborn population. The inability to identify the exposed newborn severely limits our understanding of alcohol's pathophysiological effects on developing organs such as the lung. This chapter will review potential advancements in future biomarkers of alcohol exposure for the newborn population. We will discuss alcohol's effects on redox homeostasis and cellular development of the neonatal lung. Finally, we will present the evidence describing in utero alcohol's derangement of innate and adaptive immunity and risk for infectious complications in the lung. Continued investigations into the identification and understanding of the mechanisms of alcohol-induced alterations in the premature lung will advance the care of this vulnerable patient population.

Alcohol, HIV/AIDS, and Liver Disease

Globally, there are over 33 million persons living with HIV/AIDS resulting in 1.8 million deaths annually. While the rate of HIV transmission is slowing, it is estimated that 2.6 million new infections occur yearly [1]. In the United States, there are approximately 1.2 million living with HIV/AIDS, with 50,000 new HIV infections and 17,000 deaths from the disease annually [2]. For those who can obtain effective antiretroviral therapy (ART), HIV/AIDS has become a chronic disease with life expectancies over 30 years [3]. Research in the last 10 years has revealed the importance of alcohol in the HIV/AIDS epidemic. Alcohol use, in moderate or hazardous amounts, has been associated with increased acquisition of HIV infection, progression of HIV infection, deleterious effects on HIV treatment, and acceleration in the comorbidities of HIV infection [4–9]. Yet alcohol remains the “forgotten drug” of the HIV/AIDS epidemic [10].

A dynamic flux in natural killer cell subsets as a function of the duration of alcohol ingestion

BACKGROUND

Chronic ethanol (EtOH) consumption is associated with a wide variety of immune abnormalities including changes in T cells, B cells, dendritic cells, and natural killer (NK) cells. However, there is conflicting information as to the direction of such immune changes. The hypothesis that was tested in this report is that, for NK cells, the changes can vary as a function of the duration of alcohol ingestion.

METHODS

Using the Meadows-Cook murine model of chronic alcohol ingestion, the changes in NK cell function and subset distribution were examined as a function of the duration of alcohol ingestion.

RESULTS

Acute alcohol ingestion resulted in decreased number and cytotoxic function of NK cells with no effect on intracellular interferon gamma expression. These abnormalities normalized after 12 to 14 days of alcohol ingestion and there was an increase of NK cell number and cytotoxicity after 8 weeks of continued EtOH ingestion. Ten weeks of continued alcohol consumption results in a significant decrease in the Ly49H+ CD11b+ CD27- splenic NK cell subset; this difference continued to be significant at 30 weeks.

CONCLUSIONS

This report may explain some of the conflicting data in the literature that examined NK cell activity in alcoholic patients. It is apparent that various abnormalities can be seen in NK cell activity and subset distribution with the flux being a function of the duration of alcohol ingestion. The demonstration of a decrease in the Ly49H+ subset (which is known to be involved in resisting murine cytomegalovirus infection) may explain the reported increase in susceptibility to some viral infections in chronic alcohol abuse. Another novel finding is that changes of some subsets of NK cells are not evident until at least 10 weeks of continued EtOH consumption.

The impact of alcohol on BCG-induced immunity against Mycobacterium tuberculosis

BACKGROUND

Alcoholics are at heightened risk for developing active tuberculosis. This study evaluates chronic alcohol consumption in a murine model of vaccination with Mycobacterium bovis Bacille Calmette-Guèrin (BCG) and subsequent pulmonary infection with virulent Mycobacterium tuberculosis.

METHODS

BALB/c mice were administered the Lieber-DeCarli liquid ethanol diet or pair-fed the liquid control diet for 3 weeks either before or after subcutaneous vaccination with M. bovis BCG. At least 3 weeks after BCG vaccination, groups of mice on the aforesaid diets were challenged with intratracheal infection with M. tuberculosis H37Rv. Lung mycobacterial burden, and lung and lung-associated lymph node CD4(+) lymphocyte production of tuberculosis-specific interferon (IFN)-γ were assayed. Popliteal lymph node lymphocytes from both dietary regimens undergoing BCG vaccination (in the absence of M. tuberculosis infection) were also evaluated for purified protein derivative-induced IFN-γ production by ELISpot assay.

RESULTS

Mice begun on alcohol prior to vaccination with M. bovis BCG demonstrated impaired control of pulmonary challenge with virulent M. tuberculosis, as well as impaired lung CD4(+) and popliteal lymph node T-cell IFN-γ responses. If BCG vaccination was delivered prior to initiation of alcohol feeding, the mice remained protected against a subsequent challenge with M. tuberculosis, and BCG-induced immunity was not impaired in either the lung or the popliteal lymph nodes.

CONCLUSIONS

Alcohol consumption blunts the development of the adaptive immune response to M. bovis BCG vaccination, which impairs the control of a secondary challenge with M. tuberculosis, but only if the alcohol exposure is begun prior to BCG vaccination. These results provide insight into mechanisms by which alcohol consumption impairs antimycobacterial immunity, including in response to vaccination and subsequent pathogenic challenge.

Mechanisms by which chronic ethanol feeding limits the ability of dendritic cells to stimulate T-cell proliferation

BACKGROUND

As initiators of immune responses, dendritic cells (DCs) are required for antigen (Ag)-specific activation of naïve T cells in the defense against infectious agents. The increased susceptibility to and severity of infection seen in chronic alcoholics could be because of impaired DCs initiation of naïve T-cell responses. Specifically, these DCs may not provide adequate Signals 1 (Ag presentation), 2 (costimulation), or 3 (cytokine production) to these T cells.

METHODS

Using the Meadows-Cook murine model of chronic alcohol abuse, the ability of ethanol (EtOH)-exposed DCs to stimulate T-cell proliferation, acquire and process Ag, express costimulatory molecules, and produce inflammatory cytokines was assessed.

RESULTS

Normal naïve T cells primed by EtOH-exposed DCs showed decreased proliferation in vitro and in vivo, compared to water-fed control mice. These EtOH-exposed DCs, after activation by CpG or tumor necrosis factor alpha (TNFα), were less able to upregulate costimulatory molecules CD40, CD80, or CD86, and produced less IL-12 p40, TNFα, and IFNα than DCs from water-fed mice. TLR9 and TNF receptor expression were also reduced in/on EtOH-exposed DCs. No evidence of defective Ag acquisition or processing as a result of EtOH feeding was identified.

CONCLUSIONS

Inadequate proliferation of normal T cells following stimulation by EtOH-exposed DCs is likely a result of diminished Signal 2 and Signal 3. Lack of adequate inflammatory stimulation of EtOH-exposed DCs because of diminished receptors for inflammatory mediators appears to be at least partially responsible for their dysfunction. These findings provide a mechanism to explain increased morbidity and mortality from infectious diseases in alcoholics and suggest targets for therapeutic intervention.

Chronic alcohol consumption decreases the percentage and number of NK cells in the peripheral lymph nodes and exacerbates B16BL6 melanoma metastasis into the draining lymph nodes

NK cells in the lymph nodes play important roles in inhibiting tumor metastasis into draining lymph nodes. Previously, we reported that chronic alcohol consumption interferes with NK cell trafficking from the bone marrow to the spleen. Herein, we found that alcohol consumption decreases the numbers of NK cells in lymph nodes. Adoptive transfer experiments indicated that continued exposure of donor splenocytes to alcohol inhibits NK but not T cell trafficking to lymph nodes. Alcohol did not negatively affect CCR7(+) and CXCR3(+) NK cells, but decreased the percentage and number of CD62L(+) NK cells in the spleen, which are an important source of NK cell trafficking into the lymph nodes. These data suggest that modulation of the microenvironment associated with alcohol consumption impairs the trafficking of NK cells to lymph nodes. The decreased number of NK cells in the lymph nodes was associated with increased melanoma metastasis into the draining lymph nodes.

Oseltamivir treatment prevents the increased influenza virus disease severity and lethality occurring in chronic ethanol consuming mice

BACKGROUND

Chronic consumption of ethanol (EtOH) is well recognized to lead to defective innate and adaptive immune responses and increase the severity of pulmonary infections. Our own studies have demonstrated that chronic EtOH consumption decreases CD8 T-cell immunity to influenza virus infections (IAV) leading to severe infections and mortality. Interestingly, antiviral treatment of IAVs has been shown to be compromised in mice and humans that are immuno-deficient. It is known that EtOH can alter the pharmacokinetics of antivirals. Therefore, the effectiveness of influenza antiviral therapy during chronic ethanol consumption remains in question.

METHODS

BALB/c mice were placed on 18% (w/v) EtOH in their drinking water for 8 weeks. Chronic EtOH consuming and water controls were then treated with 10 mg/kg oseltamivir orally and infected intranasally with influenza virus 4 hours post-oseltamivir treatment. The mice were then treated with oseltamivir twice daily until day 7 postinfection. Influenza disease severity was measured by morbidity and mortality, pulmonary viral titers, and histology.

RESULTS

Chronic EtOH consuming mice infected with IAV and treated with oseltamivir have decreased morbidity and mortality, pulmonary viral titers, and pulmonary pathology compared to untreated EtOH mice.

CONCLUSIONS

Despite the severe immune defect seen in chronic EtOH mice as well as the potential for EtOH to inhibit the conversion of oseltamivir into an active form, treatment with oseltamivir reduces viral shedding as well as disease severity. These data suggest that the combination of a limited adaptive immune response plus the anti-IAV drug oseltamivir is sufficient to curb high mortality and mediate resolution of IAVs in mice chronically consuming ethanol.

Alcohol's role in HIV transmission and disease progression

Alcohol use has negative effects on HIV disease progression through several mechanisms, including transmission, viral replication, host immunity, and treatment efficacy. Research with animal models has explored the effect of alcohol intake on several aspects of simian immunodeficiency virus (SIV) disease progression. Data suggest that the increased SIV levels observed in alcohol-consuming animals may represent an increase in virus production as opposed to a decrease in host defense. Results also suggest that changes in nutritional balance and metabolism, as a possible consequence of a proinflammatory state, together with increased virus production in animals consuming alcohol, accelerate SIV and possibly HIV disease progression. Further studies using the animal model are necessary.

Is ethanol consumption beneficial for oral lichen planus?

Oral lichen planus (OLP), one of the most common oral mucosa diseases, is an auto-immune disease characterized histologically by basal keratinocyte damage and interface lymphocyte reaction. Previous studies have proved ethanol consumption can suppress immune system in many aspects, including inhibiting lymphocytes proliferation and their function, modifying antigen-presentation, etc. Pathogenesis of the OLP mainly comprises of antigen-presentation, lymphocytes activation and keratinocyte apoptosis, all of which may be inhibited by ethanol consumption. Thus, we put forth our hypothesis that chronic ethanol consumption may decrease OLP incidence and OLP treatment except the erosive type may benefit from ethanol consumption. In the discussion, we also talk about the extent of ethanol consumption. Still ethanol abuse is not commended, for it may increase incidence of many other diseases, and moderate ethanol consumption may be potentially beneficial for other auto-immune diseases.