Chronic alcohol abuse and HIV disease progression: studies with the non-human primate model

Effects of drug and hazardous alcohol use on having a detectable HIV viral load: An adherence mediation analysis

Objectives

People living with HIV (PWH) with substance or alcohol use often have unsuppressed plasma HIV viral loads (pVL). The degree to which substance and alcohol use effects on HIV viral suppression are mediated through medication nonadherence is incompletely understood.

Methods

We included PWH prescribed antiretroviral therapy and receiving care at an academic HIV clinic between 2014 and 2018 who completed both patient-reported outcomes (PRO) questionnaires and had subsequent pVL measurements. Measures included assessments of alcohol use (AUDIT-C), drug use (NIDA-ASSIST), and self-reported adherence measured using four different methods. Substances found in bivariate analysis to predict detectable pVL were modeled separately for mediation effects through adherence. We report natural direct (NDE) and indirect effect (NIE), marginal total effect (MTE), and percentage mediated.

Results

Among 3125 PWH who met eligibility criteria, 25.8% reported hazardous alcohol use, 27.1% cannabis, 13.1% amphetamines, 1.9% inhalants, 5.3% cocaine, 4.5% sedative-hypnotics, 2.9% opioids, and 2.3% hallucinogens. Excellent adherence was reported by 58% of PWH, and 10% had detectable pVL. Except for sedatives, using other substances was significantly associated with worse adherence. Bivariate predictors of detectable pVL were [OR (95% CI)]: amphetamine use 2.4 (1.8-3.2) and opioid use 2.3 (1.3-4.0). The percent of marginal total effect mediated by nonadherence varied by substance: 36% for amphetamine use, 27% for opioid use, and 39% for polysubstance use.

Conclusion

Use of amphetamines, opioids, and multiple substances predicted detectable pVL. Up to 40% of their effects were mediated by self-reported nonadherence. Confirmation using longitudinal measurement models will strengthen causal inference from this cross-sectional analysis.

Transcriptional and Epigenetic Regulation of Monocyte and Macrophage Dysfunction by Chronic Alcohol Consumption

Drinking alcohol, even in moderation, can affect the immune system. Studies have shown disproportionate effects of alcohol on circulating and tissue-resident myeloid cells (granulocytes, monocytes, macrophages, dendritic cells). These cells orchestrate the body's first line of defense against microbial challenges as well as maintain tissue homeostasis and repair. Alcohol's effects on these cells are dependent on exposure pattern, with acute drinking dampening but chronic drinking enhancing production of inflammatory mediators. Although chronic drinking is associated with heightened systemic inflammation, studies on tissue resident macrophage populations in several organs including the spleen, liver, brain, and lung have also shown compromised functional and metabolic capacities of these cells. Many of these effects are thought to be mediated by oxidative stress caused by alcohol and its metabolites which can directly impact the cellular epigenetic landscapes. In addition, since myeloid cells are relatively short-lived in circulation and are under constant repopulation from the bone marrow compartment, alcohol's effects on bone marrow progenitors and hematopoiesis are important for understanding the impact of alcohol systemically on these myeloid populations. Alcohol-induced disruption of progenitor, circulating, and tissue resident myeloid populations contribute to the increased susceptibility of patients with alcohol use disorders to viral and bacterial infections. In this review, we provide an overview of the impact of chronic alcohol consumption on the function of monocytes and macrophages in host defense, tissue repair and inflammation. We then summarize our current understanding of the mechanisms underlying alcohol-induced disruption and examine changes in transcriptome and epigenome of monocytes and mcrophages. Overall, chronic alcohol consumption leads to hyper-inflammation concomitant with decreased microbial and wound healing responses by monocytes/macrophages due to a rewiring of the epigentic and transcriptional landscape. However, in advanced alcoholic liver disease, myeloid cells become immunosuppressed as a response to the surrounding hyper-inflammatory milieu. Therefore, the effect of chronic alcohol on the inflammatory response depends on disease state and the immune cell population.

Predictors of Mortality among Adult People Living with HIV and Its Implications for Appointment Spacing Model Approach Care

BACKGROUND

Ethiopia has been motivated to achieve a goal of "appointment spacing model approach care." However, little has been documented on the predictor of mortality and challenges of sustainable HIV care. Therefore, the aim of this study was to determine predictors of mortality among adult people living with HIV/AIDS on antiretroviral therapy (ART).

METHODS

A retrospective cohort study was conducted on 676 adult people living with HIV who enrolled to ART clinic from September 01, 2012 - August 30, 2016. Multivariable Cox Regression analysis was done where adjusted hazard ratio (AHR)with corresponding 95% confidence interval (CI) at P value ≤ 0.05 cut of point was used to identify predictors of mortality.

RESULTS

The total person-time contributed was 28,209 person-months with an overall mortality incidence rate of 11 per 1000 person-months observation. The cumulative mortality incidence among females over the study period was 16.8% (64/382). Severe undernourishment and moderate malnutrition at baseline, younger age, female sex, single, divorced, illiterate, lack of disclosure, advanced WHO clinical stage, seeking treatment outside catchment area, rural residence and immunological failure were found to be independent predictors of mortality.

CONCLUSIONS

Poor nutritional status at baseline, advanced stage of HIV disease, occurrence of treatment failure, female sex, substance abuse, lack of social support, immunological failure, clinical failure, and younger age, low level of education and poor physical access to healthcare facility were found to be important predictors of mortality. Intervening, those factors as routine and part of the appointment spacing model care can improve survival of PLWHA.

Chronic binge alcohol and ovariectomy dysregulate omental adipose tissue metaboproteome in simian immunodeficiency virus-infected female macaques

Effective antiretroviral therapy (ART) has significantly reduced mortality of people living with HIV (PLWH), and the prevalence of at-risk alcohol use is higher among PLWH. Increased survival and aging of PLWH is associated with increased prevalence of metabolic comorbidities especially among menopausal women, and adipose tissue metabolic dysregulation may be a significant contributing factor. We examined the differential effects of chronic binge alcohol (CBA) administration and ovariectomy (OVX) on the omental adipose tissue (OmAT) proteome in a subset of simian immunodeficiency virus (SIV)-infected macaques of a longitudinal parent study. Quantitative discovery-based proteomics identified 1,429 differentially expressed proteins. Ingenuity Pathway Analysis (IPA) was used to calculate z-scores, or activation predictions, for functional pathways and diseases. Results revealed that protein changes associated with functional pathways centered around the "OmAT metaboproteome profile." Based on z-scores, CBA did not affect functional pathways of metabolic disease but dysregulated proteins involved in adenosine monophosphate-activated protein kinase (AMPK) signaling and lipid metabolism. OVX-mediated proteome changes were predicted to promote pathways involved in glucose- and lipid-associated metabolic disease. Proteins involved in apoptosis, necrosis, and reactive oxygen species (ROS) pathways were also predicted to be activated by OVX and these were predicted to be inhibited by CBA. These results provide evidence for the role of ovarian hormone loss in mediating OmAT metaboproteome dysregulation in SIV and suggest that CBA modifies OVX-associated changes. In the context of OVX, CBA administration produced larger metabolic and cellular effects, which we speculate may reflect a protective role of estrogen against CBA-mediated adipose tissue injury in female SIV-infected macaques.

Role of non-Genetic Risk Factors in Exacerbating Alcohol-related organ damage

This review provides a summary of the symposium titled "Role of Non-Genetic Risk Factors in Exacerbating Alcohol-Related Organ Damage", which was held at the 42nd Annual Meeting of the Research Society on Alcoholism. The goals of the symposium were to provide newer insights into the role of non-genetic factors, including specific external factors, notably infectious agents or lifestyle factors, that synergistically act to exacerbate alcohol pathogenicity to generate more dramatic downstream biological defects. This summary of the symposium will benefit junior/senior basic scientists and clinicians currently investigating/treating alcohol-induced organ pathology, as well as undergraduate, graduate, and post-graduate students and fellows.

Nonhuman animal models of substance use disorders: Translational value and utility to basic science

BACKGROUND

The National Institute on Drug Abuse (NIDA) recently released a Request for Information (RFI) soliciting comments on nonhuman animal models of substance use disorders (SUD).

METHODS

A literature review was performed to address the four topics outlined in the RFI and one topic inspired by the RFI: (1) animal models that best recapitulate SUD, (2) animal models that best balance the trade-offs between resources and ecological validity, (3) animal models whose translational value are frequently misrepresented or overrepresented by the scientific community, (4) aspects of SUD that are not currently being modeled in animals, and (5) animal models that are optimal for examining the basic mechanisms by which drugs produce their abuse-related effects.

RESULTS

Models that employ response-contingent drug administration, use complex schedules of reinforcement, measure behaviors that mimic the distinguishing features of SUD, and use animals that are phylogenetically similar to humans have the greatest translational value. Models that produce stable and reproducible baselines of behavior, lessen the number of uncontrolled variables, and minimize the influence of extraneous factors are best at examining basic mechanisms contributing to drug reward and reinforcement.

CONCLUSIONS

Nonhuman animal models of SUD have undergone significant refinements to increase their utility for basic science and translational value for SUD. The existing literature describes numerous examples of how these models may best be utilized to answer mechanistic questions of drug reward and identify potential therapeutic interventions for SUD. Progress in the field could be accelerated by further collaborations between researchers using animals versus humans.

Predictors of mortality among adult people living with HIV/AIDS on antiretroviral therapy at Suhul Hospital, Tigrai, Northern Ethiopia: a retrospective follow-up study

BACKGROUND

Ethiopia is striving to achieve a goal of "zero human immune deficiency virus/acquired immune deficiency syndrome (HIV/AIDS)-related deaths." However, little has been documented on the factors that hamper the progress towards achieving this goal. Therefore, the ultimate aim of this study was to determine predictors of mortality among adult people living with HIV/AIDS on antiretroviral therapy (ART).

METHODS

A retrospective follow-up study was employed on all adult HIV/AIDS patients who started ART between January 1 and December 30, 2010, at Suhul Hospital, Tigrai Region, Northern Ethiopia. Data were collected by trained fourth-year Public Health students using a checklist. Finally, the collected data were entered into SPSS version 16. Then after, Kaplan-Meier curves were used to estimate survival probability, the log-rank test was used for comparing the survival status, and Cox proportional hazards model were applied to determine predictors of mortality.

RESULTS

The median follow-up period was 51 months (ranging between 1 and 60 months, inter-quartile range (IQR) = 14 months). At the end of follow-up, 37 (12.5%) patients were dead. The majority of these cumulative deaths, 19 (51.4%) and 29 (78.4%), occurred within 3 and 4 years of ART initiation respectively. Consuming alcohol (adjusted hazard ratio (AHR) = 2.23, 95% CI = 1.15, 4.32), low body weight (AHR = 2.38, 95% CI = 1.03, 5.54), presence of opportunistic infections (AHR = 2.18, 95% CI = 1.09, 4.37), advanced WHO clinical stage (AHR = 2.75, 95% CI = 1.36, 5.58), and not receiving isoniazid prophylactic therapy (AHR = 3.00, 95% CI = 1.33, 6.74) were found to be independent predictors of mortality.

CONCLUSION

The overall mortality was very high. Baseline alcohol consumption, low body weight, advanced WHO clinical stage, the presence of opportunistic infections, and not receiving isoniazid prophylactic therapy were predictors of mortality. Strengthening behavioral and nutritional counseling with close clinical follow-up shall be given much more emphasis in the ART care and support program.

Impact of Alcohol on HIV Disease Pathogenesis, Comorbidities and Aging: Integrating Preclinical and Clinical Findings

Short Summary

: Effective combined antiretroviral therapy regimens have extended survival of persons living with HIV (PLWH). Heavy alcohol consumption is common in PLWH. This overview integrates evidence from clinical and preclinical research to identify salient alcohol-related mechanisms and comorbidities contributing to disease pathogenesis and accelerated aging and senescence in PLWH.

Identifying the Intersection of Alcohol, Adherence and Sex in HIV Positive Men on ART Treatment in India Using an Adapted Timeline Followback Procedure

People living with HIV (PLHIV) on anti-retroviral treatment (ART) who drink are less adherent and more likely to engage in unprotected sex but the connections among these events are correlational. Using an adapted Timeline Follow-Back (A-TLFB) procedure, this paper examines the day by day interface of alcohol, medication adherence and sex to provide a fine grained understanding of how multiple behavioral risks coincide in time and space, explores concordance/discordance of measures with survey data and identifies potential recall bias. Data are drawn from a survey of behavior, knowledge and attitudes, and a 30 day TLFB assessment of multiple risk behaviors adapted for the Indian PLHIV context, administered to 940 alcohol-consuming, HIV positive men on ART at the baseline evaluation stage of a multilevel, multi-centric intervention study. On days participants drank they were significantly more likely to be medication non-adherent and to have unprotected sex. In the first day after their alcohol consuming day, the pattern of nonadherence persisted. Binge and regular drinking days were associated with nonadherence but only binge drinking co-occurred with unprotected sex. Asking about specific "drinking days" improved recall for drinking days and number of drinks consumed. Recall declined for both drinking days and nonadherence from the first week to subsequent weeks but varied randomly for sex risk. There was high concordance and low discordance between A-TLFB drinking and nonadherence but these results were reversed for unprotected sex. Moving beyond simple drinking-adherence correlational analysis, the A-TLFB offers improved recall probes and provides researchers and interventionists with the opportunity to identify types of risky days and tailor behavioral modification to reduce alcohol consumption, nonadherence and risky sex on those days.

The relationship between different dimensions of alcohol use and the burden of disease-an update

BACKGROUND AND AIMS

Alcohol use is a major contributor to injuries, mortality and the burden of disease. This review updates knowledge on risk relations between dimensions of alcohol use and health outcomes to be used in global and national Comparative Risk Assessments (CRAs).

METHODS

Systematic review of reviews and meta-analyses on alcohol consumption and health outcomes attributable to alcohol use. For dimensions of exposure: volume of alcohol use, blood alcohol concentration and patterns of drinking, in particular heavy drinking occasions were studied. For liver cirrhosis, quality of alcohol was additionally considered. For all outcomes (mortality and/or morbidity): cause of death and disease/injury categories based on International Classification of Diseases (ICD) codes used in global CRAs; harm to others.

RESULTS

In total, 255 reviews and meta-analyses were identified. Alcohol use was found to be linked causally to many disease and injury categories, with more than 40 ICD-10 three-digit categories being fully attributable to alcohol. Most partially attributable disease categories showed monotonic relationships with volume of alcohol use: the more alcohol consumed, the higher the risk of disease or death. Exceptions were ischaemic diseases and diabetes, with curvilinear relationships, and with beneficial effects of light to moderate drinking in people without heavy irregular drinking occasions. Biological pathways suggest an impact of heavy drinking occasions on additional diseases; however, the lack of medical epidemiological studies measuring this dimension of alcohol use precluded an in-depth analysis. For injuries, except suicide, blood alcohol concentration was the most important dimension of alcohol use. Alcohol use caused marked harm to others, which has not yet been researched sufficiently.

CONCLUSIONS

Research since 2010 confirms the importance of alcohol use as a risk factor for disease and injuries; for some health outcomes, more than one dimension of use needs to be considered. Epidemiological studies should include measurement of heavy drinking occasions in line with biological knowledge.

Psychosocial correlates of nutritional status among people living with HIV on antiretroviral therapy: A matched case-control study in Central zone of Tigray, Northern Ethiopia

BACKGROUND

Malnutrition hastens progression to Acquired Human Immunodeficiency Syndromes (AIDS) related illnesses; undermines adherence and response to antiretroviral therapy (ART) in resource-poor settings. However, nutritional status of people living with HIV (PLHIV) can be affected by various psychosocial factors which have not been well explored in Ethiopia. Therefore, the objective of this study was to determine psychosocial correlates of nutritional status among people living with HIV (PLHIV) on ART in Central zone of Tigray, Northern Ethiopia.

METHODS

A matched case-control study design was conducted to assess psychosocial correlates of nutritional status among PLHIV on ART. Data were collected by an interviewer-administered technique using structured pre-tested questionnaire, record review using a checklist and anthropometric measurements. Cases were selected by simple random sampling and controls purposively to match the selected cases. Conditional logistic regression was used to compute relevant associations by STATA version 12.

RESULTS

The psychosocial factors independently associated with malnutrition were ever consuming alcohol after starting ART [AOR = 4.7, 95% CI: 1.8-12.3], ever smoking cigarette after starting ART [AOR = 7.6, 95% CI: 2.3-25.5], depression [AOR = 2.8, 95% CI: 1.3, 6.1], not adhering to ART [AOR = 6.8,95% CI: 2.0-23.0] and being in the second lowest wealth quintile [AOR = 4.3,95% CI: 1.1-17.7].

CONCLUSION

Ever consuming alcohol and ever smoking cigarette after starting ART, depression, not adhering to ART and being in the second lowest wealth quintile were significantly associated with malnutrition. Therefore; policies, strategies, and programs targeting people living with HIV should consider psychosocial factors that can impact nutritional status of people living with HIV enrolled on ART.

The relationship between different dimensions of alcohol use and the burden of disease-an update

BACKGROUND AND AIMS

Alcohol use is a major contributor to injuries, mortality and the burden of disease. This review updates knowledge on risk relations between dimensions of alcohol use and health outcomes to be used in global and national Comparative Risk Assessments (CRAs).

METHODS

Systematic review of reviews and meta-analyses on alcohol consumption and health outcomes attributable to alcohol use. For dimensions of exposure: volume of alcohol use, blood alcohol concentration and patterns of drinking, in particular heavy drinking occasions were studied. For liver cirrhosis, quality of alcohol was additionally considered. For all outcomes (mortality and/or morbidity): cause of death and disease/injury categories based on International Classification of Diseases (ICD) codes used in global CRAs; harm to others.

RESULTS

In total, 255 reviews and meta-analyses were identified. Alcohol use was found to be linked causally to many disease and injury categories, with more than 40 ICD-10 three-digit categories being fully attributable to alcohol. Most partially attributable disease categories showed monotonic relationships with volume of alcohol use: the more alcohol consumed, the higher the risk of disease or death. Exceptions were ischaemic diseases and diabetes, with curvilinear relationships, and with beneficial effects of light to moderate drinking in people without heavy irregular drinking occasions. Biological pathways suggest an impact of heavy drinking occasions on additional diseases; however, the lack of medical epidemiological studies measuring this dimension of alcohol use precluded an in-depth analysis. For injuries, except suicide, blood alcohol concentration was the most important dimension of alcohol use. Alcohol use caused marked harm to others, which has not yet been researched sufficiently.

CONCLUSIONS

Research since 2010 confirms the importance of alcohol use as a risk factor for disease and injuries; for some health outcomes, more than one dimension of use needs to be considered. Epidemiological studies should include measurement of heavy drinking occasions in line with biological knowledge.

Does alcohol use have a causal effect on HIV incidence and disease progression? A review of the literature and a modeling strategy for quantifying the effect

In the first part of this review, the nature of the associations between alcohol use and HIV/AIDS is discussed. Alcohol use has been found to be strongly associated with incidence and progression of HIV/AIDS, but the extent to which this association is causal has traditionally remained in question. Experiments where alcohol use has been manipulated as the independent variable have since helped establish a causal effect of alcohol use on the intention to engage in condomless sex. As the intention to engage in condomless sex is a surrogate measure of actual condom use behavior, which itself is linked to HIV incidence and re-infection, the causal chain has been corroborated. Moreover, there are biological pathways between alcohol use and the course of HIV/AIDS, only in part being mediated by adherence to antiretroviral medication. In the second part of the contribution, we provide suggestions on the quantification of the link between alcohol use and HIV incidence, using risk relations derived from experimental data. The biological links between alcohol use and course of HIV/AIDS are difficult to quantify given the current state of knowledge, except for an operationalization for the link via adherence to medication based on meta-analyses. The suggested quantifications are exemplified for South Africa.

Validation of RPS13 as a reference gene for absolute quantification of SIV RNA in tissue of rhesus macaques

Persistent HIV reservoirs and the absolute quantification of viral RNA copies in tissues have become a prominent focus of multiple areas ofHIV/SIV research. Absolute quantification of viral RNA via reverse transcription, quantitative PCR (RT-qPCR) necessitates the use of an appropriate RNA reference gene whose expression is unaffected by both experimental and confounding conditions. In this study, we demonstrate the utility of ribosomal protein S13 mRNA (RPS13) as a stable, medium abundance reference gene for RT-qPCR normalization of HIV/SIV RNA copy number. We developed a RPS13 RNA standard assay utilizing an in vitro RNA transcript for normalization of absolute SIV RNA quantities in tissues reservoirs. The RT-qPCR assay showed a high degree of repeatability and reproducibility across RNA levels appropriate for absolute SIV quantification. In assessing the utility of RPS13 as a reference gene, limited variation in the absolute, inter-tissue quantities of RPS13 mRNA was observed within multiple tissue samples obtained from rhesus macaques (average CV=2.86%). We demonstrate rhesus macaque RPS13 mRNA expression is not affected by alcohol administration, SIV infection, or antiviral therapy (PMPA/FTC). Additionally, assay functionality was validated for normalization of SIV copy number using cellular RNA prepared from samples of variable RNA integrity. RPS13 is a suitable reference gene for normalization of absolute SIV RNA quantities in tissues and is most appropriate for intra-tissue or similar tissue type comparisons of SIV copy number.

Alcohol Use and Human Immunodeficiency Virus (HIV) Infection: Current Knowledge, Implications, and Future Directions

Alcohol use is common among people living with human immunodeficiency virus (HIV). In this narrative review, we describe literature regarding alcohol's impact on transmission, care, coinfections, and comorbidities that are common among people living with HIV (PLWH), as well as literature regarding interventions to address alcohol use and its influences among PLWH. This narrative review identifies alcohol use as a risk factor for HIV transmission, as well as a factor impacting the clinical manifestations and management of HIV. Alcohol use appears to have additive and potentially synergistic effects on common HIV-related comorbidities. We find that interventions to modify drinking and improve HIV-related risks and outcomes have had limited success to date, and we recommend research in several areas. Consistent with Office of AIDS Research/National Institutes of Health priorities, we suggest research to better understand how and at what levels alcohol influences comorbid conditions among PLWH, to elucidate the mechanisms by which alcohol use is impacting comorbidities, and to understand whether decreases in alcohol use improve HIV-relevant outcomes. This should include studies regarding whether state-of-the-art medications used to treat common coinfections are safe for PLWH who drink alcohol. We recommend that future research among PLWH include validated self-report measures of alcohol use and/or biological measurements, ideally both. Additionally, subgroup variation in associations should be identified to ensure that the risks of particularly vulnerable populations are understood. This body of research should serve as a foundation for a next generation of intervention studies to address alcohol use from transmission to treatment of HIV. Intervention studies should inform implementation efforts to improve provision of alcohol-related interventions and treatments for PLWH in healthcare settings. By making further progress on understanding how alcohol use affects PLWH in the era of HIV as a chronic condition, this research should inform how we can mitigate transmission, achieve viral suppression, and avoid exacerbating common comorbidities of HIV and alcohol use and make progress toward the 90-90-90 goals for engagement in the HIV treatment cascade.

Characterization of the Genital Microenvironment of Female Rhesus Macaques Prior to and After SIV Infection

PROBLEM

HIV infection among women is frequently modeled in female rhesus macaques. Longitudinal studies on genital compartment and hormonal factors that can influence susceptibility to SIV infection are lacking in this animal model.

METHOD OF STUDY

Genital specimens and menstruation of indoor-housed female rhesus macaques were analyzed prior to and after SIV infection.

RESULTS

Median menstrual cycle length averaged 27 days, although highly variable cycle lengths and frequent periods of amenorrhea were observed during summer months. The vaginal microbiota, characterized by adapted Nugent scoring, showed predominance of small Gram-variable rods and Gram-positive cocci. Highly variable vaginal cytokine levels were observed pre- and post-SIV infection. Vaginal viral loads correlated with plasma viral loads, but were not associated with progesterone levels.

CONCLUSION

These results provide an integrated characterization of important factors in the vaginal microenvironment that are relevant to the experimental design of HIV prevention and transmission studies in female rhesus macaques.

Chronic Binge Alcohol Administration Increases Intestinal T-Cell Proliferation and Turnover in Rhesus Macaques

BACKGROUND

Alcohol use results in changes in intestinal epithelial cell turnover and microbial translocation, yet less is known about the consequences on intestinal lymphocytes in the gut. Here, we compared T-cell subsets in the intestine of macaques before and after 3 months of chronic alcohol administration to examine the effects of alcohol on intestinal T-cell subsets.

METHODS

Rhesus macaques received either alcohol or isocaloric sucrose as a control treatment daily over a 3-month period via indwelling gastric catheters. Intestinal lymphocyte subsets were identified in biopsy samples by flow cytometry. Twenty-four hours prior to sampling, animals were inoculated with bromo-deoxyuridine (BrdU) to assess lymphocyte proliferation. Immunohistochemistry was performed on tissue samples to quantitate CD3+ cells.

RESULTS

Animals receiving alcohol had increased rates of intestinal T-cell turnover of both CD4+ and CD8+ T cells as reflected by increased BrdU incorporation. However, absolute numbers of T cells were decreased in intestinal tissues as evidenced by immunohistochemistry for total CD3 expression per mm(2) intestinal lamina propria in tissue sections. Combining immunohistochemistry and flow cytometry data showed that the absolute numbers of CD8+ T cells were significantly decreased, whereas absolute numbers of total CD4+ T cells were minimally decreased.

CONCLUSIONS

Collectively, these data indicate that alcohol exposure to the small intestine results in marked loss of CD3+ T cells, accompanied by marked increases in CD4+ and CD8+ T-cell proliferation and turnover, which we speculate is an attempt to maintain stable numbers of T cells in tissues. This suggests that alcohol results in accelerated T-cell turnover in the gut, which may contribute to premature T-cell senescence. Further, these data indicate that chronic alcohol administration results in increased levels of HIV target cells (proliferating CD4+ T cells) that may support higher levels of HIV replication in intestinal tissues.

Accounting for dropout reason in longitudinal studies with nonignorable dropout

Dropout is a common problem in longitudinal cohort studies and clinical trials, often raising concerns of nonignorable dropout. Selection, frailty, and mixture models have been proposed to account for potentially nonignorable missingness by relating the longitudinal outcome to time of dropout. In addition, many longitudinal studies encounter multiple types of missing data or reasons for dropout, such as loss to follow-up, disease progression, treatment modifications and death. When clinically distinct dropout reasons are present, it may be preferable to control for both dropout reason and time to gain additional clinical insights. This may be especially interesting when the dropout reason and dropout times differ by the primary exposure variable. We extend a semi-parametric varying-coefficient method for nonignorable dropout to accommodate dropout reason. We apply our method to untreated HIV-infected subjects recruited to the Acute Infection and Early Disease Research Program HIV cohort and compare longitudinal CD4⁺ T cell count in injection drug users to nonusers with two dropout reasons: anti-retroviral treatment initiation and loss to follow-up.