High risk of HIV-related mortality is associated with selenium deficiency

Nutrition and disease progression pre-highly active antiretroviral therapy (HAART) and post-HAART: can good nutrition delay time to HAART and affect response to HAART?

Several studies have investigated a variety of nutritional supplementation interventions in adults with HIV. In this narrative review, we summarize the evidence from 31 clinical trials that explore clinical benefits of macronutrient and micronutrient supplementation in this population while attempting to answer the question of whether good nutrition can delay the time to highly active antiretroviral therapy (HAART) initiation and response. We focused on trials published in English between 1990 and 2010 that reported on CD4 count, viral load, and disease progression or survival. Among 9 macronutrient and 22 micronutrient trials, we found that evidence for improved CD4 count and HIV viral load with nutritional supplementation was limited; only 11.1% and 36.8% of macronutrient and micronutrient supplementation trials, respectively, reported improved CD4 count; and 33.3% and 12.5% of macronutrient and micronutrient trials, respectively, reported decreased viral load. Given their utility as surrogate markers of HIV disease progression, this suggests limited evidence for nutritional interventions having an impact on delaying HAART initiation or on improving HAART response. However, there are challenges in evaluating the effects of nutritional supplementation on clinical disease in that comparisons are difficult due to heterogeneity in study design, patient population, nutrient doses and combinations, baseline levels of deficiency, and study endpoints, including lack of clarity in defining and reporting HAART status. Future studies need to adopt a more rigorous standard design with adequate power and follow-up and require a consensus on composition and dose of nutrient interventions to be tested to more specifically answer the question on the impact of nutritional interventions on HIV disease progression and HAART response.

Host factors that influence mother-to-child transmission of HIV-1: genetics, coinfections, behavior and nutrition

Mother-to-child transmission (MTCT) is the most important mode of HIV-1 acquisition among infants and children and it can occur in utero, intrapartum and postnatally through breastfeeding. Great progress has been made in preventing MTCT through use of antiretroviral regimens during gestation, labor/delivery and breastfeeding. The mechanisms of MTCT, however, are multifactorial and remain incompletely understood. This review focuses on select host factors affecting MTCT, in particular genetic factors, coexisting infections, behavioral factors and nutrition. Whereas much emphasis has been placed on decreasing maternal HIV-1 viral load, an important determinant of MTCT, through use of antiretroviral agents, complementary focus on overall maternal health is often neglected. By addressing coinfections in mothers and infants, improving the mother's nutritional status and modifying risky behaviors and practices, not only is maternal and child health improved, but a direct benefit in reducing MTCT can be derived. The study of genetic variations in susceptibility to HIV-1 infection is rapidly evolving, and the future is likely to bring revolutionary changes in HIV-1 prevention by enhancing natural resistance to infection and by individually tailoring pharmacologic regimens.

Effect of selenium supplementation on CD4 T-cell recovery, viral suppression, morbidity and quality of life of HIV-infected patients in Rwanda: study protocol for a randomized controlled trial

Background

Low levels of serum selenium are associated with increased risk of mortality among HIV+ patients in East Africa. We aim to assess the effect of selenium supplementation on CD4 cell count, HIV viral load, opportunistic infections, and quality of life in HIV-infected patients in Rwanda.

Methods and Design

A 24-month, multi-centre, patient and provider-blinded, randomized, placebo-controlled clinical trial involving 300 pre-antiretroviral therapy (ART) HIV-infected patients will be carried out at two sites in Rwanda. Patients ≥ 21 years of age with documented HIV infection, CD4 cell count of 400-650 cells/mm³, and not yet on ART will be recruited. Patients will be randomized at each study site using a randomized block design to receive either the selenium micronutrient supplement or an identically appearing placebo taken once daily. The primary outcome is a composite of time from baseline to reduction of CD4 T lymphocyte count below 350 cells/mm³ (confirmed by two measures at least one week apart), or start of ART, or the emergence of a documented CDC-defined AIDS-defining illness. An intention-to-treat analysis will be conducted using stepwise regression and structural equation modeling.

Discussion

Micronutrient interventions that aim to improve CD4 cell count, decrease opportunistic infections, decrease HIV viral load, and ultimately delay initiation of more costly ART may be beneficial, particularly in resource-constrained settings, such as sub-Saharan Africa. Additional trials are needed to determine if micro-supplementation can delay the need for more costly ART among HIV-infected patients. If shown to be effective, selenium supplementation may be of public health importance to HIV-infected populations, particularly in sub-Saharan Africa and other resource-constrained settings.

Trial Registration

NCT01327755

High rates of serum selenium deficiency among HIV- and HCV-infected and uninfected drug users in Buenos Aires, Argentina

OBJECTIVE

To describe the prevalence of low serum Se and determine whether HIV, hepatitis C virus (HCV) and/or the types of drugs used are associated with serum Se in a cohort of infected and uninfected drug users.

DESIGN

Independent correlates of low serum Se levels based on data collected from food recalls, physical examinations and clinical questionnaires were identified using multivariate regression analysis.

SETTING

Buenos Aires, Argentina

SUBJECTS

A total of 205 (twenty-five female and 180 male) former and current drug users.

RESULTS

Drug users had an average serum Se level of 69·8 (sd 32·8) μg/d, [corrected] and 82 % were considered deficient (<85 μg/l). [corrected] Multivariate analyses found that HIV- and/or HCV-infected individuals had lower mean Se compared with healthy, uninfected drug users (HIV/HCV co-infection: -25·3 μg/l (se 7·6), P = 0·001; HIV alone: -28·9 μg/l (se 6·9), P < 0·001; HCV alone: -19·4 μg/l (se 7·1), P = 0·006). Current and previous drug use was associated with higher serum Se. Cigarette smoking and heavy alcohol consumption were not found to be associated with Se status.

CONCLUSIONS

Low serum Se levels are highly prevalent among drug users in Buenos Aires, Argentina. Se supplementation and/or dietary interventions may be warranted in drug users who are at high risk for HIV and/or HCV infection.

Thymic function and T cell parameters in a natural human experimental model of seasonal infectious diseases and nutritional burden

BACKGROUND

The study exploits a natural human experimental model of subsistence farmers experiencing chronic and seasonally modified food shortages and infectious burden. Two seasons existed, one of increased deprivation and infections (Jul-Dec), another of abundance and low infections (Jan-Jun); referred to as the hungry/high infection and harvest/low infection seasons respectively. Prior analysis showed a 10-fold excess in infectious disease associated mortality in young adults born in the hungry/high infection versus harvest/low infection season, and reduced thymic output and T cell counts in infancy. Here we report findings on the role of early life stressors as contributors to the onset of T cell immunological defects in later life.

METHODS

We hypothesised that season of birth effects on thymic function and T cell immunity would be detectable in young adults since Kaplan-Meier survival curves indicated this to be the time of greatest mortality divergence. T cell subset analyses by flow-cytometry, sjTRECs, TCRVβ repertoire and telomere length by PCR, were performed on samples from 60 males (18-23 y) selected to represent births in the hungry/high infection and harvest/low infection

RESULTS

Total lymphocyte counts were normal and did not differ by birth season. CD3+ and CD4+ but not CD8+ counts were lower for those born during the hungry/high infection season. CD8+ telomere length also tended to be shorter. Overall, CD8+ TCRVβ repertoire skewing was observed with 'public' expressions and deletions seen in TCRVβ12/22 and TCRVβ24, respectively but no apparent effect of birth season.

CONCLUSIONS

We conclude that, although thymic function was unchanged, the CD4+ and CD3+ counts, and CD8+ telomere length results suggested that aspects of adult T cell immunity were under the influence of early life stressors. The endemicity of CMV and HBV suggested that chronic infections may modulate immunity through T cell repertoire development. The overall implications being that, this population is at an elevated risk of premature immunosenescence possibly driven by a combination of nutritional and infectious burden.

Selenium in human health and disease

This review covers current knowledge of selenium in the environment, dietary intakes, metabolism and status, functions in the body, thyroid hormone metabolism, antioxidant defense systems and oxidative metabolism, and the immune system. Selenium toxicity and links between deficiency and Keshan disease and Kashin-Beck disease are described. The relationships between selenium intake/status and various health outcomes, in particular gastrointestinal and prostate cancer, cardiovascular disease, diabetes, and male fertility, are reviewed, and recent developments in genetics of selenoproteins are outlined. The rationale behind current dietary reference intakes of selenium is explained, and examples of differences between countries and/or expert bodies are given. Throughout the review, gaps in knowledge and research requirements are identified. More research is needed to improve our understanding of selenium metabolism and requirements for optimal health. Functions of the majority of the selenoproteins await characterization, the mechanism of absorption has yet to be identified, measures of status need to be developed, and effects of genotype on metabolism require further investigation. The relationships between selenium intake/status and health, or risk of disease, are complex but require elucidation to inform clinical practice, to refine dietary recommendations, and to develop effective public health policies.

Postpartum thyroiditis: an autoimmune thyroid disorder which predicts future thyroid health

Postpartum thyroiditis is a potentially destructive lymphocytic thyroiditis occurring in approximately 8% of the pregnant population, making it the most common endocrine disorder associated with pregnancy. This autoimmune thyroid disorder is precipitated by the postpartum immunological rebound that follows the partial immunosuppression of pregnancy, in individuals already at risk of autoimmune thyroid disease. The manifestations of postpartum thyroiditis are usually not present at the six-week postpartum visit and thus it is important that all physicians be aware of the risks, presentation and intervention required for this common disorder. Postpartum thyroiditis is a strong predictor of future thyroid health and it is essential that women with a history of postpartum thyroiditis be screened regularly, especially prior to a future pregnancy. Selenium supplementation has recently been identified as a potential means to prevent postpartum thyroiditis in women at risk but further studies are required before recommendations for its use can be made.

Selenoprotein K knockout mice exhibit deficient calcium flux in immune cells and impaired immune responses

Selenoprotein K (Sel K) is a selenium-containing protein for which no function has been identified. We found that Sel K is an endoplasmic reticulum transmembrane protein expressed at relatively high levels in immune cells and is regulated by dietary selenium. Sel K(-/-) mice were generated and found to be similar to wild-type controls regarding growth and fertility. Immune system development was not affected by Sel K deletion, but specific immune cell defects were found in Sel K(-/-) mice. Receptor-mediated Ca(2+) flux was decreased in T cells, neutrophils, and macrophages from Sel K(-/-) mice compared with controls. Ca(2+)-dependent functions including T cell proliferation, T cell and neutrophil migration, and Fcγ receptor-mediated oxidative burst in macrophages were decreased in cells from Sel K(-/-) mice compared with that in cells from controls. West Nile virus infections were performed, and Sel K(-/-) mice exhibited decreased viral clearance in the periphery and increased viral titers in brain. Furthermore, West Nile virus-infected Sel K(-/-) mice demonstrated significantly lower survival (2 of 23; 8.7%) compared with that of wild-type controls (10 of 26; 38.5%). These results establish Sel K as an endoplasmic reticulum-membrane protein important for promoting effective Ca(2+) flux during immune cell activation and provide insight into molecular mechanisms by which dietary selenium enhances immune responses.

Role of Nutrition in HIV Infection: Review of Evidence for more Effective Programming in Resource-Limited Settings

Background

HIV infection and malnutrition negatively reinforce each other.

Objective

For program guidance, to review evidence on the relationship of HIV infection and malnutrition in adults in resource-limited settings.

Results and conclusions

Adequate nutritional status supports immunity and physical performance. Weight loss, caused by low dietary intake (loss of appetite, mouth ulcers, food insecurity), malabsorption, and altered metabolism, is common in HIV infection. Regaining weight, particularly muscle mass, requires antiretroviral therapy (ART), treatment of opportunistic infections, consumption of a balanced diet, physical activity, mitigation of side effects, and perhaps appetite stimulants and growth hormone. Correcting nutritional status becomes more difficult as infection progresses. Studies document widespread micronutrient deficiencies among HIV-infected people. However, supplement composition, patient characteristics, and treatments vary widely across intervention studies. Therefore, the World Health Organization (WHO) recommends ensuring intake of 1 Recommended Nutrient Intake (RNI) of each required micronutrient, which may require taking micronutrient supplements. Few studies have assessed the impact of food supplements. Because the mortality risk in patients receiving ART increases with lower body mass index (BMI), improving the BMI seems important. Whether this requires provision of food supplements depends on the patient's diet and food security. It appears that starting ART improves BMI and that ready-to-use fortified spreads and fortified-blended foods further increase BMI (the effect is somewhat less with fortified-blended foods). The studies are too small to assess effects on mortality. Once ART has been established and malnutrition treated, the nutritional quality of the diet remains important, also because of ART's long-term metabolic effects (dyslipidemia, insulin resistance, obesity). Food insecurity should also be addressed if it prevents adequate energy intake and reduces treatment initiation and adherence (due to the opportunity costs of obtaining treatment and mitigating side effects).

Micronutrient supplementation in children and adults with HIV infection

BACKGROUND

Micronutrient deficiencies are widespread and compound the effects of HIV disease; micronutrient supplements may be effective and safe in reducing this burden.

OBJECTIVES

To assess whether micronutrient supplements are effective and safe in reducing mortality and morbidity in adults and children with HIV infection.

SEARCH STRATEGY

The CENTRAL, EMBASE, PubMed, and GATEWAY databases were searched for randomised controlled trials of micronutrient supplements using the search methods of the Cochrane HIV/AIDS Group.

SELECTION CRITERIA

Randomised controlled trials were selected that compared the effects of micronutrient supplements (vitamins, trace elements, and combinations of these) with other supplements, placebo or no treatment on mortality, morbidity, pregnancy outcomes, immunologic indicators, and anthropometric measures in HIV-infected adults and children. Any adverse effects of supplementation were recorded.

DATA COLLECTION AND ANALYSIS

Two reviewers independently selected trials, appraised trial quality for risk of bias using standardised criteria, and extracted data using standardised forms.

MAIN RESULTS

Sixteen additional trials are included in this update to the original Cochrane review (Irlam 2005). Overall, 30 trials involving 22 120 participants are reviewed: 20 trials of single supplements (vitamin A, vitamin D, zinc, selenium) and 10 of multiple micronutrients. Eight trials were undertaken in child populations.None of the six trials of vitamin A or beta-carotene supplementation in adults demonstrated any significant reduction in HIV disease progression. Vitamin A halved all-cause mortality in a meta-analysis of three trials in African children, had inconsistent impacts on diarrhoeal and respiratory morbidity, and improved short-term growth in one trial. No significant adverse effects of vitamin A in adults or children have been reported.Zinc supplements reduced diarrhoeal morbidity and had no adverse effects on disease progression in a single safety trial in South African children. No significant clinical benefits were found from zinc supplementation of pregnant Tanzanian women or Peruvian adults with persistent diarrhoea.Selenium reduced diarrhoeal morbidity in pregnant women in Tanzania, and reduced viral load in two separate small trials in American adults.Single trials of vitamin D supplements in adults, and in adolescents and children, demonstrated safety but no clinical benefits.Multiple micronutrient supplements conferred multiple clinical benefits to pregnant women and their offspring in a large Tanzanian trial. Supplementation in another Tanzanian trial reduced the recurrence of pulmonary TB and increased weight gain in co-infected patients. No significant adverse effects were reported.

AUTHORS' CONCLUSIONS

Multiple micronutrient supplements reduced morbidity and mortality in HIV-infected pregnant women and their offspring and also improved early child growth in one large randomised controlled trial in Africa. Additional research is needed to determine if these are generalisable findings. Vitamin A supplementation is beneficial and safe in HIV-infected children, but further evidence is needed to establish if supplementation confers similar benefits in HIV-infected adults. Zinc is safe in HIV-infected adults and children. It may have similar benefits in HIV-infected children and adults, and uninfected children with diarrhoea, as it does in HIV-uninfected children.Further trials of single supplements (vitamin D, zinc, and selenium) are required to build the evidence base. The long-term clinical benefits, adverse effects, and optimal formulation of multiple micronutrient supplements require further investigation in individuals with diverse disease status. 

Echinacea purpurea along with zinc, selenium and vitamin C to alleviate exacerbations of chronic obstructive pulmonary disease: results from a randomized controlled trial

WHAT IS KNOWN AND OBJECTIVE

Upper respiratory tract infections (URTI) frequently cause exacerbations of chronic-obstructive pulmonary disease (COPD). Stimulation of the innate immune system may provide an early defence against such infections. The objective of this study was to determine whether Echinacea purpurea (EP) along with micronutrients may alleviate COPD exacerbations caused by acute URTI.

METHODS

This was a double-blind, randomized, placebo-controlled trial in COPD patients with acute URTI. Patients were given ciprofloxacin for 7 days and additionally one tablet per day of EP, of EP along with zinc, selenium and ascorbic acid (EP+), or of placebo until day 14. Serum levels of TNF α and interleukins 1β, 6 and 10 were measured before and after treatment. Until week 4 post-end of treatment, all patients had to daily report on COPD symptoms in diaries.

RESULTS AND DISCUSSION

In total, 108 mostly male patients with a mean age of 65·8 years (40-81 years) were enrolled. Patients of the three treatment arms did not vary significantly in baseline characteristics. EP+, but not EP resulted in significantly less severe and shorter exacerbation episodes following URTI as compared with placebo suggesting a synergistic effect of Echinacea and micronutrients. Large variations in biomarkers in-between and within groups were unrelated to treatment. Study medication was safe and well tolerated with overall 15 adverse events one of which was serious. Among those, sleeping disorders were most frequent and likely related to the underlying disease.

WHAT IS NEW AND CONCLUSION

The combination of EP, zinc, selenium and vitamin C may alleviate exacerbation symptoms caused by URTI in COPD. Further studies are warranted to investigate the interactions among Echinacea, zinc, selenium and vitamin C.

Management of chronic diarrhea in HIV-infected patients: current treatment options, challenges and future directions

Diarrhea is a common clinical manifestation of HIV infection regardless of whether the patients have AIDS. HIV and malnutrition tend to occur in the same populations, the underprivileged and resource-poor. Malnutrition increases severity and mortality of infection. Occurrence of chronic diarrhea in HIV-infected patients, gut status and pathogenic agents, nutritional status and the crucial role of nutrition are reviewed. Bovine colostrum-based food can be useful for managing chronic diarrhea in HIV-infected patients, enhancing both nutritional and immunological status.

Role of selenium in HIV infection

HIV infection is a global disease that disproportionately burdens populations with nutritional vulnerabilities. Laboratory experiments have shown that selenium has an inhibitory effect on HIV in vitro through antioxidant effects of glutathione peroxidase and other selenoproteins. Numerous studies have reported low selenium status in HIV-infected individuals, and serum selenium concentration declines with disease progression. Some cohort studies have shown an association between selenium deficiency and progression to AIDS or mortality. In several randomized controlled trials, selenium supplementation has reduced hospitalizations and diarrheal morbidity, and improved CD4(+) cell counts, but the evidence remains mixed. Additional trials are recommended to study the effect of selenium supplementation on opportunistic infections, and other HIV disease-related comorbidities in the context of highly active antiretroviral therapy in both developing and developed countries.

Nrf2 and selenoproteins are essential for maintaining oxidative homeostasis in erythrocytes and protecting against hemolytic anemia

Reactive oxygen species (ROS) are highly destructive toward cellular macromolecules. However, moderate levels of ROS can contribute to normal cellular processes including signaling. Herein we evaluate the consequence of a pro-oxidant environment on hematopoietic homeostasis. The NF-E2 related factor 2 (Nrf2) transcription factor regulates genes related to ROS scavenging and detoxification. Nrf2 responds to altered cellular redox status, such as occurs with loss of antioxidant selenoproteins after deletion of the selenocysteine-tRNA gene (Trsp). Conditional knockout of the Trsp gene using Mx1-inducible Cre-recombinase leads to selenoprotein deficiency and anemia on a wild-type background, whereas Trsp:Nrf2 double deficiency dramatically exacerbates the anemia and increases intracellular hydrogen peroxide levels in erythroblasts. Results indicate that Nrf2 compensates for defective ROS scavenging when selenoproteins are lost from erythroid cells. We also observed thymus atrophy in single Trsp-conditional knockout mice, suggesting a requirement for selenoprotein function in T-cell differentiation within the thymus. Surprisingly, no changes were observed in the myelomonocytic or megakaryocytic populations. Therefore, our results show that selenoprotein activity and the Nrf2 gene battery are particularly important for oxidative homeostasis in erythrocytes and for the prevention of hemolytic anemia.

Selenium deficiency and HIV infection

Selenium is a non-metallic chemical element of great important to human health. Low selenium levels in humans are associated with several pathological conditions and are a common finding in HIV infected individuals. We conducted a review of the literature to assess if selenium deficiency or selenium supplementation could play a role in modifying the clinical course of HIV disease. Several studies investigated the role of selenium in disease progression, morbidity and mortality in HIV infected individuals. Larger studies were conducted in countries with poor economic resources and limited access to HAART. According to the majority of published studies low selenium levels appear to have an association with mortality, and selenium supplementation appears to play a beneficial role on survival or on slowing disease progression among HIV infected individuals. The role of selenium supplementation on preventing hospital admission among HIV outpatients was also noticed. The literature suggests an association between selenium deficiency and development of HIV associated cardiomyopathy and furthermore, selenium supplementation appears to improve the cardiac function in HIV infected individuals with cardiomyopathy. However, there is conflicting evidence regarding the role selenium in modifying HIV viral load and immune status in HIV infection.

Micronutrients and HIV infection

The immune system requires several essential micronutrients to maintain an effective immune response. HIV infection destroys the immune system and promotes nutritional deficiencies, which further impair immunity. This article reviews the role of several micronutrients (vitamins A, C, E and D, the B vitamins, and minerals, selenium, iron and zinc) that are relevant for maintaining immune function. In addition, the deficiencies of these micronutrients have been associated with faster progression of HIV-1 disease. This review examines the evidence from observational studies of an association between micronutrient status and HIV disease, as well as the effectiveness of micronutrient supplementation on HIV-disease progression, pregnancy outcomes and nutritional status, among others, utilizing randomized clinical trials. Each micronutrient is introduced with a summary of its functions in human physiology, followed by the presentation of studies conducted in HIV-infected patients in relation to this specific micronutrient. Overall findings and recommendations are then summarized.

High-selenium wheat: biofortification for better health

The metalloid Se is ubiquitous in soils, but exists mainly in insoluble forms in high-Fe, low-pH and certain leached soils, and hence is often of limited availability to plants. Consequently, it is often supplied by plants to animals and human consumers at levels too low for optimum health. Se deficiency and suboptimality are manifested in populations as increased rates of thyroid dysfunction, cancer, severe viral diseases, cardiovascular disease and various inflammatory conditions. Se deficiency probably affects at least a billion individuals. Optimal cancer protection appears to require a supra-nutritional Se intake, and involves several mechanisms, which include promotion of apoptosis and inhibition of neo-angiogenesis. Evidence suggests that in some regions Se is declining in the food chain, and new strategies to increase its intake are required. These could include education to increase consumption of higher-Se foods, individual supplementation, food fortification, supplementation of livestock, Se fertilisation of crops and plant breeding for enhanced Se accumulation. Se levels in Australian residents and wheat appear to be above the global estimated mean. Wheat is estimated to supply nearly half the Se utilised by most Australians. Increasing the Se content of wheat represents a food systems approach that would increase population intake, with consequent probable improvement in public health and large health cost savings. The strategies that show most promise to achieve this are biofortification by Se fertilisation and breeding wheat varieties that are more efficient at increasing grain Se density. Research is needed in Australia to determine the most cost-effective fertilisation methods, and to determine the extent of genetic variability for grain Se accumulation. Before recommending large-scale fortification of the food supply with Se, it will be necessary to await the results of current intervention studies with Se on cancer, HIV and AIDS, and asthma.

Symposium on ‘Geographical and geological influences on nutrition’ Factors controlling the distribution of selenium in the environment and their impact on health and nutrition

Se is essential to human and animal health but can be toxic in excess. An interest in its geochemistry has developed alongside a greater understanding of its function in a number of health conditions. Geology exerts a strong control on the Se status of the surface environment; low-Se rock-types (0·05–0·09 mg Se/kg) make up the majority of rocks occurring at the Earth's surface, which in turn account for the generally low levels of Se in most soils. However, there are exceptions such as associations with sulfide mineralisation and in some types of sedimentary rocks (e.g. black shales) in which contents of Se can be much higher. Baseline geochemical data now enable a comparison to be made between environmental and human Se status, although a direct link is only likely to be seen if the population is dependent on the local environment for sustenance. This situation is demonstrated with an example from the work of the British Geological Survey in the Se-deficiency belt of China. The recent fall in the daily dietary Se intake in the UK is discussed in the context of human Se status and declining use of North American wheat in bread making. Generally, US wheat has ten times more Se than UK wheat, attributed to the fact that soils from the wheat-growing belt of America are more enriched in Se to a similar order of magnitude. In agriculture effective biofortification of crops with Se-rich fertilisers must be demonstrably safe to the environment and monitored appropriately and baseline geochemical data will enable this process to be done with confidence.

Factors associated with serum retinol, alpha-tocopherol, carotenoids, and selenium in Hispanics with problems of HIV, chronic hepatitis C, and drug use

The effects of hepatitis and drug use on nutritional problems in HIV infection have rarely been examined despite the importance of drug use in the global HIV pandemic. We examined the effects of HIV, hepatitis C, and drug use on serum micronutrients in 300 US Hispanic adults. Chronic hepatitis C infection was associated with lower serum retinol (-8.2 microg/dl, P < 0.0001), alpha-tocopherol (-0.10 ln microg/dl, P = 0.024), and carotenoids (-19.8 microg/dl, P < 0.0001). HIV infection was associated with lower selenium (-6.1 microg/l, P = 0.028). Elevated triglycerides in HIV infection were associated with higher serum retinol and alpha-tocopherol. Drug use was not independently associated with micronutrient alterations. We conclude that hepatitis C is an important determinant of low serum micronutrients, and should be considered in any nutritional assessment of HIV infected populations. As the safety of micronutrient supplementation is not established, policy for appropriate HIV clinical care should distinguish between populations with and without hepatitis coinfection.

The oxidative stress-induced niacin sink (OSINS) model for HIV pathogenesis

Although several specific micronutrient deficiencies are associated with disease progression and increased mortality risk in HIV/AIDS, and even a simple multivitamin/mineral supplement can prolong survival, this is typically viewed merely as nutritional support of the immune system, and only necessary if there are deficiencies to be rectified. However, the reality is more complex. Several striking nutrient-related metabolic abnormalities have been consistently documented in HIV infection. One is chronic oxidative stress, including a drastic depletion of cysteine from the glutathione pool, and a progressive decline of serum selenium that is correlated with disease progression and mortality. Another is decreased blood levels of tryptophan, with an associated intracellular niacin deficiency. Tryptophan depletion or "deletion" by induction of indoleamine-2,3-dioxygenase (IDO), the first step in oxidative tryptophan metabolism, is a known mechanism for immune suppression that is of critical importance in cancer and pregnancy, and, potentially, in HIV/AIDS. Existing evidence supports the hypothesis that these nutrient-related metabolic abnormalities in HIV infection regarding antioxidants, selenium, sulfur, tryptophan and niacin are interrelated, because HIV-associated oxidative stress can induce niacin/NAD+ depletion via activation of poly(ADP-ribose) polymerase (PARP), which could lead to tryptophan oxidation for compensatory de novo niacin synthesis, thereby contributing to immune tolerance and T-cell loss via tryptophan deletion and PARP-induced cell death. This "oxidative stress-induced niacin sink" (OSINS) model provides a mechanism whereby the oxidative stress associated with HIV infection can contribute to immunosuppression via tryptophan deletion. This model is directly supported by evidence that antioxidants can counteract indoleamine-2,3-dioxygenase (IDO), providing the critical link between oxidative stress and tryptophan metabolism proposed here. The OSINS model can be used to guide the design of nutraceutical regimens that can effectively complement antiretroviral therapy for HIV/AIDS.

Selenium supplementation in HIV-infected patients: is there any potential clinical benefit?

In HIV-infected patients undergoing antiretroviral therapy, the question of whether selenium supplementation has any therapeutic benefit is still open. With recent popular coverage of this issue, many patients have considered using selenium. Clinicians have a duty to ensure that the recommendations they make to their patients are evidence based. The literature search reported here showed that evidence to support standard selenium supplementation in patients with HIV is both limited and insufficient. To definitively answer this clinical question, the overall effect of selenium supplementation would need to be evaluated in a large randomized, controlled trial with solid methodology and strong internal validity. Although the available evidence for selenium supplementation is weak, its low toxicity and side effect profile seem to pose minimal risks, especially at low doses. For patients who want to add selenium to their regimen, discussing the potential risks and benefits as well as close follow-up is warranted.

How to use the world's scarce selenium resources efficiently to increase the selenium concentration in food

The world's rare selenium resources need to be managed carefully. Selenium is extracted as a by-product of copper mining and there are no deposits that can be mined for selenium alone. Selenium has unique properties as a semi-conductor, making it of special value to industry, but it is also an essential nutrient for humans and animals and may promote plant growth and quality. Selenium deficiency is regarded as a major health problem for 0.5 to 1 billion people worldwide, while an even larger number may consume less selenium than required for optimal protection against cancer, cardiovascular diseases and severe infectious diseases including HIV disease. Efficient recycling of selenium is difficult. Selenium is added in some commercial fertilizers, but only a small proportion is taken up by plants and much of the remainder is lost for future utilization. Large biofortification programmes with selenium added to commercial fertilizers may therefore be a fortification method that is too wasteful to be applied to large areas of our planet. Direct addition of selenium compounds to food (process fortification) can be undertaken by the food industry. If selenomethionine is added directly to food, however, oxidation due to heat processing needs to be avoided. New ways to biofortify food products are needed, and it is generally observed that there is less wastage if selenium is added late in the production chain rather than early. On these bases we have proposed adding selenium-enriched, sprouted cereal grain during food processing as an efficient way to introduce this nutrient into deficient diets. Selenium is a non-renewable resource. There is now an enormous wastage of selenium associated with large-scale mining and industrial processing. We recommend that this must be changed and that much of the selenium that is extracted should be stockpiled for use as a nutrient by future generations.

The effect of selenium supplementation on DTH skin responses in healthy North American men

The trace element selenium (Se) is essential for immune system development and function in animals. However, the exact functions of Se in the human immune system and the achievable health benefits from Se supplementation remain unclear. To test whether an increased intake of dietary Se affects immune function, we conducted a randomized, controlled trial of Se supplementation in healthy free-living men. Forty-two men were administered 300microg of Se a day as high-Se Baker's yeast, or low-Se yeast for 48 weeks. Serum immunoglobulins, differential complete blood counts and lymphocyte sub-populations were measured every 6 weeks. Tests of delayed-type hypersensitivity (DTH) skin responses to mumps, candida, trychophyton, tuberculin-purified protein, and tetanus were performed at baseline and at the end of 48 weeks of treatment. Supplementation increased blood Se concentration by 50%. Surprisingly, consumption of the low-Se yeast induced anergy in DTH skin responses and increased counts of natural killer (NK) cells and T lymphocytes expressing both subunits of the high affinity interleukin-2 receptor (IL2R). DTH skin responses and IL2R+ cells did not change in the high-Se group, suggesting Se supplementation blocked induction of DTH anergy. There were no differences between groups in quality of life indicators, number of days sick, other leukocyte phenotypes, serum immunoglobulins, or complement factors. These results suggest that Se plays a role in immunotolerization, a cell-mediated process involved in many aspects of immune function.

The influence of selenium on immune responses

Selenium (Se) is a potent nutritional antioxidant that carries out biological effects through its incorporation into selenoproteins. Given the crucial roles that selenoproteins play in regulating reactive oxygen species (ROS) and redox status in nearly all tissues, it is not surprising that dietary Se strongly influences inflammation and immune responses. The notion that Se "boosts" the immune system has been supported by studies involving aging immunity or protection against certain pathogens. However, studies examining the effects of Se status on other types of immunity such as antiparasitic responses or allergic asthma have suggested more Se may not always be beneficial. In this review, we summarize and compare the available data regarding how the levels of Se affect different types of immunity. Overall, determining how Se intake differentially affects various types of immune responses and dissecting the mechanisms by which this occurs will lead to a better utilization of Se-supplementation for human diseases involving the immune system.

Nutritional status and serum zinc and selenium levels in Iranian HIV infected individuals

BACKGROUND

Human immunodeficiency virus infected individuals are prone to malnutrition due to increased energy requirements, enteropathy and increased catabolism. Trace elements such as zinc and selenium have major role in maintaining a healthy immune system. This study was designed to evaluate the nutritional status of Iranian subjects who were newly diagnosed with human immunodeficiency virus infection and to compare serum level of zinc and selenium in these patients with those of the sex and aged match healthy subjects.

METHODS

After an interview and physical examination, nutritional assessment was done based on clinical and anthropometric parameters. Body mass index (normal range 18.5-27 kg/m2 based on age) of less than 16, 16-16.9 and 17-18.4 kg/m2 were considered as severe, moderate and mild malnutrition respectively. Serum level of zinc and selenium were measured by graphite furnace atomic absorption.

RESULTS

Severe, moderate and mild malnutrition were detected in 15%, 38% and 24% of human immunodeficiency virus infected individuals respectively. Compared with the healthy control group, serum level of zinc and selenium in the human immunodeficiency virus infected subjects were significantly lower (P = 0.01 and P = 0.02 respectively).

CONCLUSION

Malnutrition found to be prevalent in Iranian human immunodeficiency virus infected individuals and low serum zinc and selenium levels are common in this population.

Thioredoxin reductase-1 negatively regulates HIV-1 transactivating protein Tat-dependent transcription in human macrophages

Epidemiological studies suggest a correlation between severity of acquired immunodeficiency syndrome (AIDS) and selenium deficiency, indicating a protective role for this anti-oxidant during HIV infection. Here we demonstrate that thioredoxin reductase-1 (TR1), a selenium-containing pyridine nucleotide-disulfide oxidoreductase that reduces protein disulfides to free thiols, negatively regulates the activity of the HIV-1 encoded transcriptional activator, Tat, in human macrophages. We used a small interfering RNA approach as well as a high affinity substrate of TR1, ebselen, to demonstrate that Tat-dependent transcription and HIV-1 replication were significantly increased in human macrophages when TR1 activity was reduced. The increase in HIV-1 replication in TR1 small interfering RNA-treated cells was independent of the redox-sensitive transcription factor, NF-kappaB. These studies indicate that TR-1 acts as a negative regulator of Tat-dependent transcription. Furthermore, in vitro biochemical assays with recombinant Tat protein confirmed that TR1 targets two disulfide bonds within the Cys-rich motif required for efficient HIV-1 transactivation. Increasing TR1 expression along with other selenoproteins by supplementing with selenium suggests a potential inexpensive adjuvant therapy for HIV/AIDS patients.

Food-chain selenium and human health: emphasis on intake

Following the publication of the landmark trial of Clark et al. in 1996 that appeared to show that Se could reduce the risk of cancer, awareness of the importance of Se to human health has markedly increased. As a result, there is now much more aggressive marketing of Se supplements and functional foods, even in situations where additional consumption of Se is inappropriate. The present review addresses how Se gets into the food chain, the wide variability in Se content of foods and the very different levels of intake between countries and regions. Though it is clear that there are adverse consequences for health of both deficient and excessive intake, health effects at intermediate levels of intake are less certain. Thus it is difficult to define optimal intake which depends on a large number of factors, such as which functions of Se are most relevant to a particular disease state, which species of Se is most prominent in the Se source, which health condition is being considered, the adequacy or otherwise of intake of other nutrients, the presence of additional stressors, and lastly whether the ability to make selenoproteins may be compromised. These complexities need to be understood, particularly by policy makers, in order to make informed judgments. Potential solutions for increasing Se intake, where required, include agronomic biofortification and genetic biofortification or, for individuals, increased intake of naturally Se-rich foods, functional foods or supplements. The difficulties of balancing the risks and benefits in relation to Se intake are highlighted.

Randomized, double-blind, placebo-controlled trial of selenium supplements among HIV-infected pregnant women in Tanzania: effects on maternal and child outcomes

BACKGROUND

In observational studies, adequate selenium status has been associated with better pregnancy outcomes and slowed HIV disease progression.

OBJECTIVE

We investigated the effects of daily selenium supplements on CD4 cell counts, viral load, pregnancy outcomes, and maternal and infant mortality among 913 HIV-infected pregnant women.

DESIGN

In this randomized, double-blind, placebo-controlled trial, eligible women between 12 and 27 wk of gestation were given daily selenium (200 mug as selenomethionine) or placebo as supplements from recruitment until 6 mo after delivery. All women received prenatal iron, folic acid, and multivitamin supplements irrespective of experimental assignment.

RESULTS

The selenium regimen had no significant effect on maternal CD4 cell counts or viral load. Selenium was marginally associated with a reduced risk of low birth weight [relative risk (RR) = 0.71; 95% CI: 0.49, 1.05; P = 0.09] and increased risk of fetal death (RR = 1.58; 95% CI = 0.95, 2.63; P = 0.08), but had no effect on risk of prematurity or small-for-gestational age birth. The regimen had no significant effect on maternal mortality (RR = 1.02; 95% CI = 0.51, 2.04; P = 0.96). There was no significant effect on neonatal or overall child mortality, but selenium reduced the risk of child mortality after 6 wk (RR = 0.43; 95% CI = 0.19, 0.99; P = 0.048).

CONCLUSION

Among HIV-infected women from Dar es Salaam, Tanzania, selenium supplements given during and after pregnancy did not improve HIV disease progression or pregnancy outcomes, but may improve child survival. This trial was registered at clinicaltrials.gov as NCT00197561.

Micronutrients and T-cell subsets: a comparison between HIV-infected and uninfected, severely malnourished Rwandan children

OBJECTIVE

To determine the levels of CD4+ cells and micronutrients in HIV-infected and uninfected severely malnourished children.

DESIGN

Cross-sectional study in two centres.

SETTING

Children admitted to the malnutrition units in Kigali and Butare, Rwanda.

PATIENTS

A total of 112 children aged 2 months to 5 years presenting with severe malnutrition (weight for height Z- score -3 SD +/- oedema). Fifty-two (46.4%) were HIV-infected.

METHODS

CD4+ counts, selenium, zinc and copper levels were measured. The percentage of CD4 cells was calculated as a proportion of total lymphocyte count.

RESULTS

The mean age of the 52 HIV-infected children (18 months) was lower than of the 60 uninfected children (26 months) (p=0.01). Six (11.5%) of the HIV-infected had oedematous malnutrition compared with 50% of the uninfected group. The mean (SD) CD4+ count was 1054 (780) in the HIV-infected and 1579 (721) in the uninfected group (p=0.001). The CD4+ count was also significantly lower in the HIV-infected group than in the uninfected group for the ages <12 mths (p=0.09), 12-24 mths (p=0.045) and >36 mths (p=0.001). In HIV-infected children, 17% had severe immunosuppression (<15% CD4+ cells), 33% moderate (15-24%) and 50% had none (>25%) compared with 9%, 12% and 80% in the HIV-uninfected group, respectively (p<0.001). Approximately one-third in both groups had low levels of selenium and zinc and 77% had raised levels of copper. In multivariate analysis there was significant correlation between selenium and CD4+ (r=0.36, p<0.001) in HIV-infected children and no correlation of zinc and copper to CD4+ %. In HIV uninfected children, CD4+ % was related to selenium (r=0.282, p=0.03) and to zinc (r=0.264, p=0.047) but not to copper.

CONCLUSIONS

In severely malnourished children with HIV infection, low CD4+ levels are associated mainly with HIV infection. There was no significant difference in levels of selenium, zinc and copper between HIV-infected and uninfected children.

Effects of selenium status and supplementary seleno-chemical sources on mouse T-cell mitogenesis

Although selenium is thought to be essential for various immune responses, the excess supplementation may have an adverse effect on certain immunological functions. The present study was designed to determine the effective chemical forms of selenium and their optimal levels on T-cell mitogenesis with splenic cells from mice given a selenium-deficient diet for 8 weeks to avoid effects of cellular selenium sources. Although selenium in tissues, except for spleen and thymus, was almost depleted by feeding selenium-deficient diet, the lymphoid organs still contained low levels of selenium. Both activities of cellular glutathione peroxidase (cGPx) and thioredoxin reductase (TR) in liver and splenic cells showed a tendency to decrease by selenium deficiency. However, splenic cells were tolerant against decrease of the selenoenzyme activities, and TR was also more tolerant than cGPx. T-cell proliferation of the selenium-insufficient splenic cells induced by concanavalin A was increased by addition of Na2SeO3, Na2SeO4, Na2Se, seleno-DL-cystine, seleno-L-methionine and selenocystamine. Their promoting action was observed at levels lower than 0.1 micromol/L and was completely suppressed at the highest concentration (1 micromol/L), except for selenocystamine. Na2SeO3 was one of the efficient selenocompounds for the mitogenesis, which was concomitant with the significant induction of cGPx and TR. However, recovery of cGPx activity in the selenium-insufficient cells by supplementary Na2SeO3 was only partial,while TR activity was readily recovered from selenium deficiency. These results therefore indicate that only low levels of selenium is essential for T-cell mitogenesis even in selenium-insufficient splenic cells, and TR, which is readily recovered by Na2SeO3, may be the critical enzyme.

Undernutrition, infection and immune function

Undernutrition and infection are the major causes of morbidity and mortality in the developing world. These two problems are interrelated. Undernutrition compromises barrier function, allowing easier access by pathogens, and compromises immune function, decreasing the ability of the host to eliminate pathogens once they enter the body. Thus, malnutrition predisposes to infections. Infections can alter nutritional status mediated by changes in dietary intake, absorption and nutrient requirements and losses of endogenous nutrients. Thus, the presence of infections can contribute to the malnourished state. The global burden of malnutrition and infectious disease is immense, especially amongst children. Childhood infections impair growth and development. There is a role for breast-feeding in protection against infections. Key nutrients required for an efficient immune response include vitamin A, Fe, Zn and Cu. There is some evidence that provision of the first three of these nutrients does improve immune function in undernourished children and can reduce the morbidity and mortality of some infectious diseases including measles, diarrhoeal disease and upper and lower respiratory tract infections. Not all studies, however, show benefit of single nutrient supplementation and this might be because the subjects studied have multiple nutrient deficiencies. The situation regarding Fe supplementation is particularly complex. In addition to immunization programmes and improvement of nutrient status, there are important roles for maternal education, improved hygiene and sanitation and increased supply of quality water in the eradication of infectious diseases.

Metabolic regulation and function of glutathione peroxidase-1

Glutathione peroxidase-1 (GPX1) represents the first identified mammalian selenoprotein, and our understanding in the metabolic regulation and function of this abundant selenoenzyme has greatly advanced during the past decade. Selenocysteine insertion sequence-associating factors, adenosine, and Abl and Arg tyrosine kinases are potent, Se-independent regulators of GPX1 gene, protein, and activity. Overwhelming evidences have been generated using the GPX1 knockout and transgenic mice for the in vivo protective role of GPX1 in coping with oxidative injury and death mediated by reactive oxygen species. However, GPX1 exerts an intriguing dual role in reactive nitrogen species (RNS)-related oxidative stress. Strikingly, knockout of GPX1 rendered mice resistant to toxicities of drugs including acetaminophen and kainic acid, known as RNS inducers. Intracellular and tissue levels of GPX1 activity affect apoptotic signaling pathway, protein kinase phosphorylation, and oxidant-mediated activation of NFkappaB. Data are accumulating to link alteration or abnormality of GPX1 expression to etiology of cancer, cardiovascular disease, neurodegeneration, autoimmune disease, and diabetes. Future research should focus on the mechanism of GPX1 in the pathogeneses and potential applications of GPX1 manipulation in the treatment of these disorders.

Nutritional status in patients with HIV infection and AIDS

The aim of this study was to evaluate the nutritional status of adults with HIV infection or with AIDS through the use of biochemical parameters. The study was performed on 43 patients (19 HIV+ and 24 AIDS patients), between 26 and 44 years of age, from low and medium socioeconomic status, with access to health care services; 35 patients were under highly active antiretroviral therapy (HAART) treatment. Body weight and height were determined, and the Body Mass Index calculated (kg/m2). Blood samples were collected from fasting patients. Plasma cholesterol (total, HDL and LDL), triacylglycerol, total protein, apolipoproteins A-I and B, albumin, transthyretin, retinol binding protein, and ceruloplasmin concentrations were determined. Plasma levels of zinc, copper, and selenium were determined in a haemolysis-free sample by flame atomic absorption spectrometry. Statistical analyses were performed with the Student's t-test. AIDS patients showed changes in biochemical parameters, particularly an increase in fibrinogen and a trend to decreased transthyretin levels. These findings stress the importance of the inclusion of functional biochemical parameters in the periodic evaluation of these patients. This would allow an early assessment of the need for appropriate nutritional support, implemented along with the specific retroviral treatment. This would aim at delaying the progression of the disease, and might improve the prospects of survival and quality of life.

Host-pathogen evolution: Implications for the prevention and treatment of malaria, myocardial infarction and AIDS

Humans have evolved complex immune systems to protect against infection by pathogens. However, pathogens possess a remarkable genetic versatility that allows them to gain new vigour and so escape such population immunity. Conflicting pathogen-host objectives, therefore, lead to the evolutionary equivalent of an "arms race". Typically, in this struggle, pathogens attempt to deplete their host of specific nutrients that are essential for immune system function. After infection, the resulting deficiency of nutrient(s) may cause many of the disease symptoms and sequela. In malaria, Plasmodium falciparum, for example, depletes its host of Vitamin A, possibly resulting in blindness in some cases. However, 200,000 International Units of Vitamin A, given to children every three months can reduce significantly their susceptibility to malaria. This would seem to be a minimum child dosage for the treatment of the disease. In contrast, the Coxsackie B virus causes a selenium deficiency that may result in myocardial infarction or Keshan disease. However, table salt fortified with 15ppm anhydrous sodium selenite can cause dramatic drops in the incidence of Keshan disease, while selenium supplementation also reduces re-infarction rates. HIV-1 depletes its host of four nutrients: selenium, cysteine, glutamine and tryptophan, resulting in symptoms known as AIDS. Open and closed clinical trials in South Africa, Zambia and Uganda, involving daily adult doses of 600mcg l-selenomethione, and some 500mg l-glutamine, hydroxytryptophan and N-acetyl cysteine, however, have shown that such supplementation can reverse the symptoms of AIDS and prevent HIV-1 infected patients declining into this disease. It is obvious, therefore, that supplementation of diet with specific nutrients can reduce infection by particular pathogens. In addition, if infection still occurs, their use as a treatment may prevent many of the symptoms and sequela commonly associated with diseases such as malaria, myocardial infarction and AIDS.

Higher pre-infection vitamin E levels are associated with higher mortality in HIV-1-infected Kenyan women: a prospective study

Background

Low vitamin E levels are often found in HIV-1 infection, and studies have suggested that higher levels may decrease the risk of disease progression. However, vitamin E supplementation has also been reported to increase CCR5 expression, which could increase HIV-1 replication. We hypothesized that vitamin E levels at HIV-1 acquisition may influence disease progression.

Methods

Vitamin E status was measured in stored samples from the last pre-infection visit for 67 Kenyan women with reliably estimated dates of HIV-1 acquisition. Regression analyses were used to estimate associations between pre-infection vitamin E and plasma viral load, time to CD4 count <200 cells/μL, and mortality.

Results

After controlling for potential confounding factors, each 1 mg/L increase in pre-infection vitamin E was associated with 0.08 log₁₀ copies/mL (95% CI -0.01 to +0.17) higher set point viral load and 1.58-fold higher risk of mortality (95% CI 1.15–2.16). The association between higher pre-infection vitamin E and mortality persisted after adjustment for set point viral load (HR 1.55, 95% CI 1.13–2.13).

Conclusion

Higher pre-infection vitamin E levels were associated with increased mortality. Further research is needed to elucidate the role vitamin E plays in HIV-1 pathogenesis.

Micronutrients in HIV-positive persons receiving highly active antiretroviral therapy

In HIV-infected persons, low serum concentrations of vitamins and minerals, termed micronutrients, are associated with an increased risk of HIV disease progression and mortality. Micronutrient supplements can delay HIV disease progression and reduce mortality in HIV-positive persons not receiving highly active antiretroviral therapy (HAART). With the transition to more universal access to HAART, a better understanding of micronutrient deficiencies and the role of micronutrient supplements in HIV-positive persons receiving HAART has become a priority. The provision of simple, inexpensive micronutrient supplements as an adjunct to HAART may have several cellular and clinical benefits, such as a reduction in mitochondrial toxicity and oxidative stress and an improvement in immune reconstitution. We reviewed observational and trial evidence on micronutrients in HIV-positive persons receiving HAART to summarize the current literature and suggest future research priorities. A small number of observational studies have suggested that some, but not all, micronutrients may become replete after HAART initiation, and few intervention studies have found that certain micronutrients may be a beneficial adjunct to HAART. However, most of these studies had some major limitations, including a small sample size, a short duration of follow-up, a lack of adjustment for inflammatory markers, and an inadequate assessment of HIV-related outcomes. Therefore, few data are available to determine whether HAART ameliorates micronutrient deficiencies or to recommend or refute the benefit of providing micronutrient supplements to HIV-positive persons receiving HAART. Because micronutrient supplementation may cause harm, randomized placebo-controlled trials are needed. Future research should determine whether HAART initiation restores micronutrient concentrations, independent of inflammatory markers, and whether micronutrient supplements affect HIV-related outcomes in HIV-positive persons receiving HAART.