Age-related immune dysfunction in health and in human immunodeficiency virus (HIV) disease: association of age and HIV infection with naive CD8+ cell depletion, reduced expression of CD28 on CD8+ cells, and reduced thymic volumes

HIV and Menopause: A Systematic Review of the Effects of HIV Infection on Age at Menopause and the Effects of Menopause on Response to Antiretroviral Therapy

More than half of persons living with HIV infection in the United States (U.S.) will be ≥50 years of age by 2020, including postmenopausal women. We conducted a systematic literature review about the effects of (1) HIV infection on age at menopause and (2) menopause on antiretroviral therapy (ART) response, in order to inform optimal treatment strategies for menopausal women living with HIV infection. We used the Ovid Medline database from 1980 to 2012. We included studies that focused on HIV-infected persons, included postmenopausal women, and reported outcome data for either age at menopause or response to ART across menopause. We identified six original research articles for age at menopause and five for response to ART across menopause. Our review revealed that current data were conflicting and inconclusive; more rigorous studies are needed. Disentangling the effects of menopause requires well-designed studies with adequate numbers of HIV-infected and HIV-uninfected women, especially disproportionately affected women of color. Future studies should follow women from premenopause through menopause, use both surveys and laboratory measurements for menopause diagnoses, and control for confounders related to normal aging processes, in order to inform optimal clinical management for menopausal women living with HIV.

Microbial translocation, residual viremia and immune senescence in the pathogenesis of HIV-1 infection

The pathophysiological mechanisms that underlie the progression of human immunodeficiency virus-1 (HIV-1) disease to full-blown AIDS are not well understood. Findings suggest that, during HIV-1 infection, plasma lipopolysaccharide (LPS) levels, which are used as an indicator of microbial translocation (MT), are elevated throughout the acute and chronic phases of HIV-1 disease. The translocation of bacterial products through the damaged gastrointestinal barrier into the systemic circulation has been described as a driver of immune activation. In contrast, comorbidities that are associated with HIV-1 infection have been attributed to chronic inflammation and immune system dysfunction secondary to MT or low-level HIV-1 replication in plasma and cell reservoirs. Moreover, accelerated aging is significantly associated with chronic inflammation, immune activation, and immune senescence. In this review, we aimed to investigate the role of inflammation as a pivotal marker in the pathogenesis of HIV-1 disease. We will discuss the key features of chronic inflammation and immune activation that are observed during the natural course of the disease and those features that are detected in cART-modified infection. The review will focus on the following aspects of HIV-1 infection: (1) MT; (2) the role of residual viremia; and (3) “immune senescence” or “inflammaging.” Many questions remain unanswered about the potential mechanisms that are involved in HIV-1 pathogenesis. Further studies are needed to better investigate the mechanisms that underlie immune activation and their correlation with HIV-1 disease progression.

Population specific reference ranges of CD3, CD4 and CD8 lymphocyte subsets among healthy Kenyans

Background

The enumeration of absolute CD4 counts is of primary importance for many medical conditions especially HIV infection where therapeutic initiation depends on the count. These ranges tend to vary across populations. However, these ranges have not been comprehensively established in the Kenyan population. Therefore, this study aimed at establishing the reference ranges for the CD4 and CD8 T-lymphocytes in normal healthy individuals in Kenya.

Methods

A total of 315 individuals of the ages between 16 and 60 years old, in 5 different regions of the country, were recruited into the study. They were screened for diseases that potentially cause lymphocyte homeostasis perturbation. CD4/CD8 Counts were performed by use of a FACSCalibur flow cytometer (Becton-Dickinson, NJ) equipped with automated acquisition and analysis software. Results were analysed according to age, sex and region.

Results

Results were presented as means and ranges (in parenthesis) generated non parametrically as 2.5 and 97.5 percentiles as follows; In general population; CD3 1655 (614-2685 cells/μL ), CD4 920 (343-1493 cells/μL), and CD8 646 (187-1139 cells/μL), while according to sex, females; CD3 1787 (697-2841 cells/μL), CD4 1010 (422-1572 cells/μL), CD8 659 (187-1180 cells/μL); males; CD3 1610 (581-2641 cells/μL), CD4 889(320-1459 cells/μL) and CD8 644 (185-1140 cells/μL). The general reference ranges for CD4/CD8 ratios were as follows; general population 1.57(0.50-2.74), males 1.51(0.49-2.64) and females 1.69(0.55-2.95).

Conclusion

The lymphocyte reference ranges for the Kenyan population are fairly comparable to those established in other African populations. The ranges also differ appreciably from those established in Germany, Italy and Switzerland. Furthermore, the study reported significant differences in the ranges of different population clusters within Kenya, as well us between males and females.

Older HIV-infected patients on antiretroviral therapy have B-cell expansion and attenuated CD4 cell increases with immune activation reduction

BACKGROUND

The contribution of immune activation to accelerated HIV-disease progression in older individuals has not been delineated.

METHODS

Prospective multicenter cohort of older (≥45 years) and younger (18-30 years) HIV-infected adults initiating 192 weeks of antiretroviral therapy (ART). Longitudinal models of CD4 cell restoration examined associations with age-group, thymic volume, immune activation, and viral load.

RESULTS

Forty-five older and 45 younger adults (median age 50 and 26 years, respectively) were studied. Older patients had fewer naive CD4 cells (P<0.001) and higher HLA-DR/CD38 expression on CD4 (P=0.05) and CD8 cells (P=0.07) than younger patients at any time on ART. The rate of naive and total CD4 cell increase was similar between age groups, but older patients had a faster mean rate of B-cell increase (by +0.7 cells/week; P=0.01), to higher counts than healthy controls after 192 weeks (P=0.003). Naive CD4 increases from baseline were associated with immune activation reductions (as declines from baseline of %CD8 cells expressing HLA-DR/CD38; P<0.0001), but these increases were attenuated in older patients, or in those with small thymuses. A 15% reduction in activation was associated with naive gains of 29.9 and 6.2 cells/μl in younger, versus older patients, or with gains of 25.7, 23.4, and 2.1 cells/μl in patients with the largest, intermediate, and smallest thymuses, respectively (P<0.01 for interactions between activation reduction and age-group or thymic volume).

CONCLUSION

Older patients had significant B-cell expansion, higher levels of immune activation markers, and significantly attenuated naive CD4 cell gains associated with activation reduction.

T-cell subset distribution in HIV-1-infected patients after 12 years of treatment-induced viremic suppression

OBJECTIVE

Residual immune activation and skewed T cell maturation may contribute to excess comorbidity and mortality in successfully treated HIV-infected patients, and long-term effects of combination antiretroviral therapy (cART) on immune reconstitution remain a debated issue. Quantitative T cell reconstitution and activation and its association with residual viremia in patients with 12 years of viremic suppression were investigated.

DESIGN

Blood samples collected cross-sectionally from 71 HIV-infected patients with cART-induced viremic suppression through 12 years were compared with samples from 16 healthy controls.

METHODS

Several different subsets of naive, memory, and activated T cells were analyzed in fresh whole blood by 6-color flowcytometry, and ultrasensitive quantification of HIV RNA was performed.

RESULTS

HIV-infected patients had lower absolute and relative CD4 T cell counts and higher absolute and relative CD8 T cell counts than controls. HIV-infected patients had lower concentrations of naive CD4 cells than controls, but proportions were similar. HIV-infected patients had higher concentrations of CD8 T cells than controls in all the examined subsets but only a higher proportion of CD8 cells in the intermediately differentiated and activated subsets. Residual viremia did not correlate to proportions of naive CD4, CD4 recent thymic emigrants, or activated CD8 T cells.

CONCLUSIONS

This study demonstrated some degree of T cell imbalance even after 12 years of successful cART. Large longitudinal studies are needed to establish whether these discrete changes have clinical relevance.

Lack of evidence for mtDNA as a biomarker of innate immune activation in HIV infection

Many human immunodeficiency virus (HIV) infected individuals suffer from persistent immune activation. Chronic inflammation and immune dysregulation have been associated with an increased risk of age-related diseases even among patients on highly active antiretroviral therapy. The factors leading to immune activation are complex, but have been hypothesized to include persistent viral replication with cellular death as well as microbial translocation across the gastrointestinal tract. Both processes may trigger innate immune responses since many native molecules released from dying cells are similar in structure to pathogen associated molecular patterns. These damage associated molecular patterns include mitochondrial DNA and formylated peptides. We hypothesized that circulating mitochondrial nucleic acid could serve as a biomarker for HIV-associated cell death and drive innate immune activation in infected individuals. We developed a quantitative polymerase chain reaction assay for plasma mitochondrial DNA and validated it on normal blood donors. We then measured mitochondrial DNA levels in acute and chronic HIV infection. While the assay proved to be accurate with a robust dynamic range, we did not find a significant association between HIV disease status and circulating mitochondrial DNA. We did, however, observe a negative correlation between age and plasma mitochondrial DNA levels in individuals with well-controlled HIV.

Accelerated Aging in HIV Patients

Life expectancy has been increasing in the last few decades in the Western world and is accompanied by higher occurrence of age-related diseases like metabolic, cardiovascular, and renal diseases and also with a decline in immune functions. In HIV-infected people, due to the use of combination antiretroviral therapy (cART), life expectancy has increased. As a result, non-AIDS conditions which are age-associated have become more prevalent and appear earlier, resulting in accelerated aging in HIV patients. These non-AIDS conditions in HIV patients are associated with CD4+ T cell counts: lower counts are associated with higher rates of liver, cardiovascular, renal, and neurocognitive disorders. The effect of viral load and cART on the earlier occurrence of age-associated diseases is less significant than the CD4 count effect. Thus, the loss of immune functions in HIV-infected patients may enhance aging.

Age-related expansion of Tim-3 expressing T cells in vertically HIV-1 infected children

As perinatally HIV-1-infected children grow into adolescents and young adults, they are increasingly burdened with the long-term consequences of chronic HIV-1 infection, with long-term morbidity due to inadequate immunity. In progressive HIV-1 infection in horizontally infected adults, inflammation, T cell activation, and perturbed T cell differentiation lead to an "immune exhaustion", with decline in T cell effector functions. T effector cells develop an increased expression of CD57 and loss of CD28, with an increase in co-inhibitory receptors such as PD-1 and Tim-3. Very little is known about HIV-1 induced T cell dysfunction in vertical infection. In two perinatally antiretroviral drug treated HIV-1-infected groups with median ages of 11.2 yr and 18.5 yr, matched for viral load, we found no difference in the proportion of senescent CD28(-)CD57(+)CD8(+) T cells between the groups. However, the frequency of Tim-3(+)CD8(+) and Tim-3(+)CD4(+) exhausted T cells, but not PD-1(+) T cells, was significantly increased in the adolescents with longer duration of infection compared to the children with shorter duration of HIV-1 infection. PD-1(+)CD8(+) T cells were directly associated with T cell immune activation in children. The frequency of Tim-3(+)CD8(+) T cells positively correlated with HIV-1 plasma viral load in the adolescents but not in the children. These data suggest that Tim-3 upregulation was driven by both HIV-1 viral replication and increased age, whereas PD-1 expression is associated with immune activation. These findings also suggest that the Tim-3 immune exhaustion phenotype rather than PD-1 or senescent cells plays an important role in age-related T cell dysfunction in perinatal HIV-1 infection. Targeting Tim-3 may serve as a novel therapeutic approach to improve immune control of virus replication and mitigate age related T cell exhaustion.

High IL-10 production by aged AIDS patients is related to high frequency of Tr-1 phenotype and low in vitro viral replication

This work aims to elucidate the effects of age and HIV-1 infection on the frequency and function of T cell subsets in response to HIV-specific and non-specific stimuli. As compared with the younger AIDS group, the frequencies of naive and central memory T cells were significantly lower in aged AIDS patients. Although there was also a dramatic loss of classical CD4(+)FoxP3(+)CD25(+)Treg cells in this patient group, high frequencies of IL-10-producing CD4(+)FoxP3(-) T cells were observed. In our system, the increased production of IL-10 in aged AIDS patients was mainly derived from Env-specific CD4(+)FoxP3(-)CD152(+) T cells. Interestingly, while the blockade of IL-10 activity by monoclonal antibody clearly enhanced the release of IL-6 and IL-1β by Env-stimulated PBMC cultures from aged AIDS patients, this monoclonal antibody enhanced in vitro HIV-1-replication. In conclusion, HIV infection and aging undoubtedly contribute synergistically to a complex immune dysfunction in T cell compartment of HAART-treated older HIV-infected individuals.

T cell subsets in HIV infected patients after successful combination antiretroviral therapy: impact on survival after 12 years

OBJECTIVES

Immune activation is decreased by combination antiretroviral therapy (cART) in patients infected with human immunodeficiency virus (HIV), but residual activation remains and has been proposed as a cause of premature aging and death, but data are lacking. We analyzed the relationship between T-cell subsets after 18 months of cART and overall survival during 12 years of follow up.

METHODS

A cohort of 101 HIV infected patients who had undetectable plasma HIV after starting cART was included in 1997-1998. T cell subsets were analyzed by flowcytometry after 18 months of cART. Relation to survival was calculated using Kaplan-Meier curves and multiple Cox regression.

RESULTS

Seventeen patients died during the observation period. The leading causes of death were non-AIDS cancer and cardiovascular disease. Higher levels of CD8 memory T cells (CD8+,CD45RO+,CD45RA-) showed a significant beneficiary effect on survival, HR of 0.95 (95% confidence interval 0.91-0.99, P = 0.016) when adjusted for age, nadir CD4 count, CD4 count, and AIDS and hepatitis C status. T cell activation was not associated with increased risk of death.

CONCLUSIONS

Larger and longitudinal studies are needed to accurately establish prognostic factors, but overall results seem to suggest that prognostic information exists within the CD8 compartment.

CCR5 expression is elevated on endocervical CD4+ T cells in healthy postmenopausal women

BACKGROUND

New HIV-1 infections are increasing in older American women largely through heterosexual transmission. Activated CD4+ T cells and CCR5 expression are linked to HIV-1 susceptibility, but whether these parameters are altered in the cervix of older women is unknown.

METHODS

Whole blood and in some instances endocervical brush samples were collected from healthy premenopausal (n = 22) and postmenopausal women (n = 24). Percentages of HLA-DR(DR)+CD38(38)+CD4+ T cells and HIV-1 chemokine coreceptor expression were determined by flow cytometry.

RESULTS

Percentages of DR+38+CD4+ T cells were 6 times greater in cervix (median: 6.4%) than blood (median: 1.1%; P < 0.001) but did not differ within each compartment between premenopausal and postmenopausal women (P = 0.2). Postmenopausal women had greater percentages of CCR5+CD4+ and CCR5+DR+38+CD4+ T cells compared with premenopausal women in cervix (median: 70% vs. 42%, P = 0.005; and 80% vs. 57%; P = 0.05, respectively) and blood (medians: 22% vs. 13%, and 76% vs. 62%, respectively; P < 0.001). Postmenopausal women had more CCR5 molecules on cervical DR+38+CD4+ T cells (median: 3176) than premenopausal women (median: 1776; P = 0.02). Age and percent CCR5+CD4+ and CCR5+DR+38+CD4+ cells were linearly related in cervix (r(2) = 0.47, P < 0.001 and r(2) = 0.25, P = 0.01, respectively) and blood (r(2) = 0.20, P = 0.001 and r(2) = 0.31, P < 0.001; respectively), but confounding of age with menopause could not be excluded. Cervical CXCR4 expression did not differ substantially between premenopausal and postmenopausal women.

CONCLUSIONS

Elevated cervical CCR5 expression in postmenopausal women may increase their risk for HIV-1 acquisition. Studies are needed to confirm whether elevated CCR5 expression confers increased HIV-1 susceptibility in postmenopausal women, and if it is related to hormonal or nonhormonal effects of aging.

CD28-negative CD4+ and CD8+ T cells in antiretroviral therapy-naive HIV-infected adults enrolled in adult clinical trials group studies

BACKGROUND

Individuals infected with human immunodeficiency virus (HIV) have higher risk than HIV-negative individuals for diseases associated with aging. T-cell senescence, characterized by expansion of cells lacking the costimulatory molecule CD28, has been hypothesized to mediate these risks.

METHODS

We measured the percentage of CD28(-)CD4(+) and CD8(+) T cells from HIV-infected treatment-naive adults from 5 Adult Clinical Trials Group (ACTG) antiretroviral therapy (ART) studies and the ALLRT (ACTG Longitudinal Linked Randomized Trials) cohort, and from 48 HIV-negative adults. Pretreatment and 96-week posttreatment %CD28(-) cells were assessed using linear regression for associations with age, sex, race/ethnicity, CD4 count, HIV RNA, ART regimen, and hepatitis C virus (HCV) infection.

RESULTS

In total, 1291 chronically HIV-infected adults were studied. Pretreatment, lower CD4 count was associated with higher %CD28(-)CD4(+) and %CD28(-)CD8(+) cells. For CD8(+) cells, younger age and HCV infection were associated with a lower %CD28(-). ART reduced %CD28(-) levels at week 96 among virally suppressed individuals. Older age was strongly predictive of higher %CD28(-)CD8(+). Compared to HIV-uninfected individuals, HIV-infected individuals maintained significantly higher %CD28(-).

CONCLUSIONS

Effective ART reduced the proportion of CD28(-) T cells. However, levels remained abnormally high and closer to levels in older HIV-uninfected individuals. This finding may inform future research of increased rates of age-associated disease in HIV-infected adults.

HIV infection, aging and cardiovascular disease: epidemiology and prevention

In the developed world, HIV infection is now well managed with very effective and less toxic antiretroviral treatment. HIV-positive patients therefore are living longer, but are now faced by challenges associated with aging. Several non-AIDS associated morbidities are increased in this population, including cardiovascular disease (CVD). It is suggested that CVD occurs earlier among HIV-positive patients compared with HIV-negative patients, and at a higher rate. Several factors have been proposed to contribute to this. First, the traditional CVD risk factors are highly prevalent in this population. High rates of smoking, dyslipidaemia and a family history of CVD have been reported. This population is also aging, with estimates of more than 25% of HIV-positive patients in the developed world being over the age of 50. Antiretroviral treatment, both through its effect on lipids and through other, sometimes less well understood, mechanisms, has been linked to increased CVD risk. HIV infection, especially untreated, is a further contributing factor to increased CVD risk in HIV-positive patients. As the HIV-positive population continues to age, the risk of CVD will continue to increase. Guidelines for the management and prevention of CVD risk have been developed, and are largely modelled on those used in the general population. However, the data currently suggest that these interventions, such as the use of lipid-lowering medications and smoking cessation programs, remain quite low. A better understanding the mechanisms of CVD risk in this aging population and further efforts in improving uptake of prevention strategies will remain an important research area.

Mechanisms of immunosenescence: lessons from models of accelerated immune aging

With increasing age, the ability of the adaptive immune system to respond to vaccines and to protect from infection declines. In parallel, the production of inflammatory mediators increases. While cross-sectional studies have been successful in defining age-dependent immunological phenotypes, studies of accelerated immune aging in human subpopulations have been instrumental in obtaining mechanistic insights. The immune system depends on its regenerative capacity; however, the T cell repertoire, once established, is relatively robust to aging and only decompensates when additionally stressed. Such stressors include chronic infections such as CMV and HIV, even when viral replication is controlled, and autoimmune diseases. Reduced regenerative capacity, chronic immune activation in the absence of cell exhaustion, T cell memory inflation, and accumulation of highly potent effector T cells in these patients synergize to develop an immune phenotype that is characteristic of the elderly. Studies of accelerated immune aging in autoimmune diseases have identified an unexpected link to chronic DNA damage responses that are known to be important in aging, but so far had not been implicated in immune aging.

Lung Disease in Older Patients with HIV

Successful treatment of HIV with combination antiretroviral therapy (ART) has resulted in an aging HIV-infected population. As HIV-infected patients are living longer, noninfectious pulmonary diseases are becoming increasingly prevalent with a proportional decline in the incidence of opportunistic infections (OIs). Pulmonary OIs such as Pneumocystis jirovecii pneumonia (PCP) and tuberculosis are still responsible for a significant proportion of pulmonary diseases in HIV-infected patients. However, bacterial pneumonia (BP) and noninfectious pulmonary diseases such as chronic obstructive pulmonary disease (COPD), lung cancer, pulmonary arterial hypertension (PAH), and interstitial lung disease (ILD) account for a growing number of pulmonary diseases in aging HIV-infected patients. The purpose of this chapter is to discuss the spectrum and management of pulmonary diseases in aging HIV-infected patients, although limited data exists to guide management of many noninfectious pulmonary diseases in HIV-infected patients. In the absence of such data, treatment of lung diseases in HIV-infected patients should generally follow guidelines for management established in HIV-uninfected patients.

Accelerated aging and human immunodeficiency virus infection: emerging challenges of growing older in the era of successful antiretroviral therapy

HIV-infected patients are living longer as a result of potent antiretroviral therapy. Immuno-inflammatory phenomena implicated in the normal aging process, including immune senescence, depreciation of the adaptive immune system, and heightened systemic inflammation are also pathophysiologic sequelae of HIV infection, suggesting HIV infection can potentiate the biological mechanisms of aging. Aging HIV-infected patients manifest many comorbidities at earlier ages, and sometimes with more aggressive phenotypes compared to seronegative counterparts. In this review, we describe relevant biologic changes shared by normal aging and HIV infection and explore the growing spectrum of clinical manifestations associated with the accelerated aging phenotype in HIV-infected individuals.

Poorer ART outcomes with increasing age at a large public sector HIV clinic in Johannesburg, South Africa

BACKGROUND

As the current HIV-positive population ages, the absolute number of patients >50 years on treatment is increasing.

METHODS

We analyze the differences in treatment outcomes by age category (18-29, 30-39, 40-49, 50-59, and ≥ 60) among 9139 HIV-positive adults initiating ART in South Africa.

RESULTS

The adjusted hazard ratios (HRs) for all-cause mortality increased with increasing age, with the strongest association in the first 12 months of follow-up among patients 50 to 59 years (HR 1.67; 95% confidence interval [CI]: 1.24-2.23) versus those <30 years. However, patients 50 to 59 years were less likely to be lost during 24 months on antiretroviral therapy ([ART] HR 0.75; 95% CI: 0.59-0.94) versus patients <30 years. By 6 and 12 months on treatment, older patients were less likely to increase their CD4 count by ≥ 50 cells/mm(3).

CONCLUSION

Although older patients are at higher risk of mortality and have poorer immunological responses than their younger counterparts, they are more likely to adhere to care and treatment in the first 24 months on ART.

Old age and anti-cytomegalovirus immunity are associated with altered T-cell reconstitution in HIV-1-infected patients

OBJECTIVE AND DESIGN

Increasing evidence supports a parallel between HIV-1 infection and immune aging, which is particularly apparent with common changes in naive versus memory T-cell proportions. Here, we aimed at refining the value of common T-cell-associated markers of immunosenescence during HIV disease progression or aging, and at exploring further the impact in this context of old age as well as cytomegalovirus (CMV) co-infection, which is predominant in HIV-1-infected individuals.

METHODS

Frequencies of naive or CD57(+) memory T cells as well as the magnitude of CMV-pp65 T cells were measured in HIV-1-infected patients grouped according to disease progression status, treatment and age.

RESULTS

Our results indicate that the decline in naive T-cell levels rather than the accumulation of CD57(+) senescent T cells identifies best the premature development of an immunosenescence phenotype with HIV disease progression. Moreover, advanced age or mounting of strong CMV-specific responses impact independently on CD4(+) T-cell counts and recovery with antiretroviral therapy.

CONCLUSIONS

The present findings indicate that HIV-1 infection amplifies the effect of age on naive T-cell levels, and highlight the constraint on the capacity of treated patients to reconstitute their CD4(+) T-cell compartment due to age and CMV co-infection.

Taking stock of infections and antibiotic resistance in the elderly and long-term care facilities: A survey of existing and upcoming challenges

Treating elderly patients with infections represents one of the greatest challenges to health-care providers. Older adults are the largest growing sector of the population and suffer excessively from infectious diseases such as pneumonia, urinary tract infections (UTIs), and skin and soft-tissue infections. Often because of disabilities, the elderly require treatment of infectious diseases in long-term care facilities (LTCFs). As a result of antibiotic use, LTCFs have become "reservoirs of resistance" and multi-drug resistant (MDR) pathogens are frequently recovered. Clinicians also need to be aware of the impairment of immune function and other emerging chronic infections (HIV, HCV) that are now present in the elderly. Despite vigilance regarding this issue, delays in diagnosis and initiation of therapy are common. This article reviews the changing landscape of infections in the elderly and the challenge these syndromes present in the context of an increasing older population that requires dedicated resources.

Does HAART efficacy translate to effectiveness? Evidence for a trial effect

BACKGROUND

Patients who participate in clinical trials may experience better clinical outcomes than patients who initiate similar therapy within clinical care (trial effect), but no published studies have evaluated a trial effect in HIV clinical trials.

METHODS

To examine a trial effect we compared virologic suppression (VS) among patients who initiated HAART in a clinical trial versus in routine clinical care. VS was defined as a plasma HIV RNA ≤ 400 copies/ml at six months after HAART initiation and was assessed within strata of early (1996-99) or current (2000-06) HAART periods. Risk ratios (RR) were estimated using binomial models.

RESULTS

Of 738 persons initiating HAART, 30.6% were women, 61.7% were black, 30% initiated therapy in a clinical trial and 67% (n =  496) had an evaluable six month HIV RNA result. HAART regimens differed between the early and current periods (p < 0.001); unboosted PI regimens (55.6%) were more common in the early and NNRTI regimens (46.4%) were more common in the current period. Overall, 78% (95%CI 74, 82%) of patients achieved VS and trial participants were 16% more likely to achieve VS (unadjusted RR 1.16, 95%CI 1.06, 1.27). Comparing trial to non-trial participants, VS differed by study period. In the early period, trial participants initiating HAART were significantly more likely to achieve VS than non-trial participants (adjusted RR 1.33; 95%CI 1.15, 1.54), but not in the current period (adjusted RR 0.98; 95%CI 0.87, 1.11).

CONCLUSIONS

A clear clinical trial effect on suppression of HIV replication was observed in the early HAART period but not in the current period.

A challenge for the future: aging and HIV infection

Older individuals (≥50 years of age) are increasingly becoming a new at-risk group for HIV-1 infection and, together with those surviving longer due to the introduction of anti-retroviral therapy (ART), it is predicted that more than half of all HIV-1-infected individuals in the United States will be greater than 50 years of age in the year 2015. Older individuals diagnosed with HIV-1 are prone to faster disease progression and reduced T-cell reconstitution despite successful virologic control with anti-retroviral therapy (ART). There is also growing evidence that the T-cell compartment in HIV-1(+) adults displays an aged phenotype, and HIV-1-infected individuals are increasingly diagnosed with clinical conditions more commonly seen in older uninfected persons. As aging in the absence of HIV infection is associated with alterations in T-cell function and immunosenescence, the combined impact of both HIV-1 infection and aging may provide an explanation for poorer clinical outcomes observed in older HIV-1-infected individuals. Thus, the development of novel therapeutics to stimulate immune function and delay immunosenescence is critical and would be beneficial to both the elderly and HIV-1-infected individuals.

Baseline immune phenotypes and CD4+ T lymphocyte responses to antiretroviral therapy in younger versus older HIV-infected individuals

OBJECTIVE

The purpose of the study was to determine associations between pre-antiretroviral therapy (ART) senescent CD8+ T lymphocytes and naïve versus non-naive CD8+ and CD4+ T lymphocyte subpopulations and CD4+ responses after initiation of ART in younger versus older individuals.

METHODS

Retrospective analysis of 100 subjects with pre-ART cryopreserved peripheral blood mononuclear cells samples was performed with flow cytometry. Subjects were divided into four groups by age (30-50 years or > 50 years) and 96-week CD4+ response (<100 or >200 cells/mm(3)). All subjects had 96-week viral suppression to <50 copies/mm(3). Regression was utilized to investigate associations between pre-ART CD8+ and CD4+ T cell phenotypes with age and CD4+ response categories.

RESULTS

Individuals <50 years had a lower frequency of senescent CD8+ T lymphocytes of the CD56 + 57+, CD56+, and CD28- phenotypes (95%CI -3.6 to -0.02; 95%CI -4.2 to -0.03; 95%CI -12.5 to -1.4, respectively) and a higher frequency of naïve (CD45RA + CD28+) CD8+ T lymphocytes (95%CI 2.6 to 10.9). Younger age and good CD4+ response were associated with a higher frequency of pre-ART naïve CD4+ T cells (95%CI 2.0 to 16.4 and 95%CI 1.5 to 15.6, respectively).

CONCLUSIONS

Prior to ART, younger HIV-infected individuals have a higher frequency of naïve CD4+ and CD8+ T cells and lower frequency of senescent CD8+ T cell phenotypes.

An epidemic in evolution: the need for new models of HIV care in the chronic disease era

Since the beginning of the AIDS epidemic, models of HIV care have needed to be invented or modified as the needs of patients and communities evolved. Early in the epidemic, primary care and palliative care predominated; subsequently, the emergence of effective therapy for HIV infection led to further specialization and a focus on increasingly complex antiretroviral therapy as the cornerstone of effective HIV care. Over the past decade, factors including (1) an aging, long-surviving population; (2) multiple co-morbidities; (3) polypharmacy; and (4) the need for chronic disease management have led to a need for further evolution of HIV care models. Moreover, geographic diffusion; persistent disparities in timely HIV diagnosis, treatment access, and outcomes; and the aging of the HIV provider workforce also suggest the importance of reincorporating primary care providers into the spectrum of HIV care in the current era. Although some HIV-dedicated treatment centers offer comprehensive medical services, other models of HIV care potentially exist and should be developed and evaluated. In particular, primary care- and community-based collaborative practices-where HIV experts or specialists are incorporated into existing health centers-are one approach that combines the benefits of HIV-specific expertise and comprehensive primary care using an integrated, patient-centered approach.

HIV infection, inflammation, immunosenescence, and aging

Although antiretroviral therapy for HIV infection prevents AIDS-related complications and prolongs life, it does not fully restore health. Long-term treated patients remain at higher than expected risk for a number of complications typically associated with aging, including cardiovascular disease, cancer, osteoporosis, and other end-organ diseases. The potential effect of HIV on health is perhaps most clearly exhibited by a number of immunologic abnormalities that persist despite effective suppression of HIV replication. These changes are consistent with some of the changes to the adaptive immune system that are seen in the very old ("immunosenescence") and that are likely related in part to persistent inflammation. HIV-associated inflammation and immunosenescence have been implicated as causally related to the premature onset of other end-organ diseases. Novel therapeutic strategies aimed at preventing or reversing these immunologic defects may be necessary if HIV-infected patients are to achieve normal life span.

HIV disease progression despite suppression of viral replication is associated with exhaustion of lymphopoiesis

The mechanisms of CD4(+) T-cell count decline, the hallmark of HIV disease progression, and its relationship to elevated levels of immune activation are not fully understood. Massive depletion of CD4(+) T cells occurs during the course of HIV-1 infection, so that maintenance of adequate CD4(+) T-cell levels probably depends primarily on the capacity to renew depleted lymphocytes, that is, the lymphopoiesis. We performed here a comprehensive study of quantitative and qualitative attributes of CD34(+) hematopoietic progenitor cells directly from the blood of a large set of HIV-infected persons compared with uninfected donors, in particular the elderly. Our analyses underline a marked impairment of primary immune resources with the failure to maintain adequate lymphocyte counts. Systemic immune activation emerges as a major correlate of altered lymphopoiesis, which can be partially reversed with prolonged antiretroviral therapy. Importantly, HIV disease progression despite elite control of HIV replication or virologic success on antiretroviral treatment is associated with persistent damage to the lymphopoietic system or exhaustion of lymphopoiesis. These findings highlight the importance of primary hematopoietic resources in HIV pathogenesis and the response to antiretroviral treatments.

A low T regulatory cell response may contribute to both viral control and generalized immune activation in HIV controllers

HIV-infected individuals maintaining undetectable viremia in the absence of therapy (HIV controllers) often maintain high HIV-specific T cell responses, which has spurred the development of vaccines eliciting HIV-specific T cell responses. However, controllers also often have abnormally high T cell activation levels, potentially contributing to T cell dysfunction, CD4+ T cell depletion, and non-AIDS morbidity. We hypothesized that a weak T regulatory cell (Treg) response might contribute to the control of viral replication in HIV controllers, but might also contribute to generalized immune activation, contributing to CD4+ T cell loss. To address these hypotheses, we measured frequencies of activated (CD38+ HLA-DR+), regulatory (CD4+CD25+CD127^dim), HIV-specific, and CMV-specific T cells among HIV controllers and 3 control populations: HIV-infected individuals with treatment-mediated viral suppression (ART-suppressed), untreated HIV-infected “non-controllers” with high levels of viremia, and HIV-uninfected individuals. Despite abnormally high T cell activation levels, controllers had lower Treg frequencies than HIV-uninfected controls (P = 0.014). Supporting the propensity for an unusually low Treg response to viral infection in HIV controllers, we observed unusually high CMV-specific CD4+ T cell frequencies and a strong correlation between HIV-specific CD4+ T cell responses and generalized CD8+ T cell activation levels in HIV controllers (P≤0.001). These data support a model in which low frequencies of Tregs in HIV controllers may contribute to an effective adaptive immune response, but may also contribute to generalized immune activation, potentially contributing to CD4 depletion.

The molecular pathogenesis of HIV-1 associated nephropathy: recent advances

HIV-1-associated nephropathy (HIVAN) is a major complication of HIV-1 infection, frequently resulting in kidney failure. HIVAN arises due to HIV-1-induced dysregulation of podocytes, the glomerular epithelial cells that establish and maintain the kidney filtration barrier. Host genetic factors are important for the development of HIVAN. The risk of HIVAN is greatest in populations of African ancestry, and is attributable to a genetic variation at the APOL1 locus on chromosome 22. Mouse models of HIVAN enable delineation of dysregulated pathways underlying disease. Identification of HIVAN susceptibility loci in a mouse model, combined with expression quantitative trait locus mapping, has demonstrated that murine HIVAN loci transregulate podocyte gene expression. HIV-1 induces perturbations in podocyte expression response, suggesting that HIV-1 potentially interferes with compensatory pathways that normally restore cellular homeostasis in the face of genetic mutations. These findings present a framework for identification of podocyte transregulators and reconstruction of the molecular networks connecting susceptibility genes to the development of nephropathy.

Immunologic basis for revaccination of HIV-infected children receiving HAART

With increasing access to antiretroviral therapy for children infected with HIV, especially in sub-Saharan Africa, better understanding of the development and maintenance of memory T- and B-cell responses to pathogens after immune reconstitution is needed to assess the risk of infection. Knowledge of long-term immune responses after starting HAART is of particular importance for policies on revaccination of HIV-infected children, who may lose protective immunity to prior infections and immunizations. We review normal development of T- and B-cell memory responses to viruses and vaccines against viral pathogens, and contrast the immunological effects of perinatal HIV transmission with HIV infection acquired later in life. We then explore the potential benefits of antiretroviral therapy and revaccination, using measles virus as a model.

CD4 count at presentation for HIV care in the United States and Canada: are those over 50 years more likely to have a delayed presentation?

We assessed CD4 count at initial presentation for HIV care among ≥50-year-olds from 1997-2007 in 13 US and Canadian clinical cohorts and compared to <50-year-olds. 44,491 HIV-infected individuals in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) were included in our study. Trends in mean CD4 count (measured as cells/mm³) and 95% confidence intervals ([,]) were determined using linear regression stratified by age category and adjusted for gender, race/ethnicity, HIV transmission risk and cohort. From 1997-2007, the proportion of individuals presenting for HIV care who were ≥50-years-old increased from 17% to 27% (p-value < 0.01). The median CD4 count among ≥50 year-olds was consistently lower than younger adults. The interaction of age group and calendar year was significant (p-value <0.01) with both age groups experiencing modest annual improvements over time (< 50-year-olds: 5 [4 , 6] cells/mm3; ≥50-year-olds: 7 [5 , 9] cells/mm³), after adjusting for sex, race/ethnicity, HIV transmission risk group and cohort; however, increases in the two groups were similar after 2000. A greater proportion of older individuals had an AIDS-defining diagnosis at, or within three months prior to, first presentation for HIV care compared to younger individuals (13% vs. 10%, respectively). Due to the increasing proportion, consistently lower CD4 counts, and more advanced HIV disease in adults ≥50-year-old at first presentation for HIV care, renewed HIV testing efforts are needed.

Pneumonia and influenza hospitalization in HIV-positive seniors

HIV-positive persons and the elderly have increased risk for influenza-related complications, including pneumonia. Using claims data for pneumonia and influenza (P&I) hospitalization in the USA, we described the temporo-demographic trends and in-patient case-fatality in persons aged ≥ 65 years by HIV status. Our results showed a near doubling in the fraction of P&I admissions representing HIV-positive persons between 1991 and 2004 [relative risk (RR) 1·95, 95% confidence interval (CI) 1·80-2·13]. HIV-positive adults were younger (70·3 vs. 79·9 years, P<0·001), and had higher case-fatality (18·0% vs. 12·6%, P<0·001). Adjusting for other variables, case-fatality decreased by 5·8% in HIV-positive persons with the availability of highly active antiretroviral therapy (P=0·032). However, HIV-positive seniors were still 51% more likely to die during hospitalization than HIV-negative persons in 2004 (OR 1·51, 95% CI 1·23-1·85). HIV-infected persons represent a growing fraction of the elderly population hospitalized with P&I. Additional measures are needed to reduce case-fatality associated with P&I in this population.

Virologic and immunologic response to HAART, by age and regimen class

OBJECTIVE

To determine the impact of age and initial HAART regimen class on virologic and immunologic response within 24 months after initiation.

DESIGN

Pooled analysis of data from 19 prospective cohort studies in the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD).

METHODS

Twelve thousand, one hundred and ninety-six antiretroviral-naive adults who initiated HAART between 1998 and 2008 using a boosted protease inhibitor-based regimen or a nonnucleoside reverse transcriptase inhibitor (NNRTI)-based regimen were included in our study. Discrete time-to-event models estimated adjusted hazard odds ratios (aHOR) and 95% confidence intervals (CIs) for suppressed viral load (≤500 copies/ml) and, separately, at least 100 cells/μl increase in CD4 cell count. Truncated, stabilized inverse probability weights accounted for selection biases from discontinuation of initial regimen class.

RESULTS

Among 12 196 eligible participants (mean age = 42 years), 50% changed regimen classes after initiation (57 and 48% of whom initiated protease inhibitor and NNRTI-based regimens, respectively). Mean CD4 cell count at initiation was similar by age. Virologic response to treatment was less likely in those initiating using a boosted protease inhibitor [aHOR = 0.77 (0.73, 0.82)], regardless of age. Immunologic response decreased with increasing age [18-<30: ref; 30-<40: aHOR = 0.92 (0.85, 1.00); 40-<50: aHOR = 0.85 (0.78, 0.92); 50-<60: aHOR = 0.82 (0.74, 0.90); ≥60: aHOR = 0.74 (0.65, 0.85)], regardless of initial regimen.

CONCLUSION

We found no evidence of an interaction between age and initial antiretroviral regimen on virologic or immunologic response to HAART; however, decreased immunologic response with increasing age may have implications for age-specific when-to-start guidelines.

The effect of aging, nutrition, and exercise during HIV infection

Medical advances continue to change the face of human immunodeficiency virus- acquired immunodeficiency syndrome (HIV/AIDS). As life expectancy increases, the number of people living with HIV rises, presenting new challenges for the management of a chronic condition. Aging, nutrition, and physical activity can influence outcomes in other chronic conditions, and emerging data show that each of these factors can impact viral replication and the immune system in HIV. HIV infection results in a decline of the immune system through the depletion of CD4+ T cells. From initial infection, viral replication is a continuous phenomenon. Immunosenescence, a hallmark of aging, results in an increased susceptibility to infections secondary to a delayed immune response, and this phenomenon may be increased in HIV-infected patients. Optimal nutrition is an important adjunct in the clinical care of patients with HIV. Nutritional interventions may improve the quality and span of life and symptom management, support the effectiveness of medications, and improve the patient's resistance to infections and other disease complications by altering immunity. Moderate physical activity can improve many immune parameters, reduce the risk of acute infection, and combat metabolic abnormalities. As people with HIV age, alternative therapies such as nutrition and physical activity may complement medical management.

The ageing of HIV: implications for geriatric medicine

The prevalence of human immunodeficiency virus (HIV) in the over 50 age group is increasing as a consequence of younger adults ageing with HIV, in addition to new diagnoses in later life. We conducted searches in MEDLINE for English language studies published between January 1984 and January 2010 using search terms 'HIV', 'AIDS', 'HIV testing' and 'HIV complications' and selected articles relevant to adults aged 50 years and over. The prevalence, natural history and complications of HIV infection and treatment in older adults are reviewed. In 2007 the Centers for Disease Control and Prevention in the United States reported that 16.8% of new diagnoses of HIV that year were in individuals aged over 50 years. Older adults are vulnerable to late or missed diagnosis, and poorer treatment outcomes, due to the misconception that they are not at risk. A heightened awareness of HIV as a possible diagnosis in older adults is becoming increasingly important. As the HIV population ages, the emergence of disease and treatment complications such as cardiovascular disease, osteoporosis and dementia are evident. Management of older adults with HIV and multiple co-morbidities presents challenges to infectious diseases physicians and geriatricians alike. Inclusion of older adults in future HIV clinical trials will help design healthcare models to provide for this growing population.

Immune activation, apoptosis, and Treg activity are associated with persistently reduced CD4+ T-cell counts during antiretroviral therapy

BACKGROUND

Persistently reduced CD4(+) T-lymphocyte counts in the face of undetectable HIV viremia are seen in a sizable percentage of HIV-infected patients undergoing antiretroviral therapy (ART). We analyzed the immune correlates of this phenomenon.

MATERIALS AND METHODS

Sixty-seven HIV-infected patients with undetectable viremia (<50 copies/microl) after more than 7 years of ART were enrolled in the study and divided into two groups (CD4 cell counts >500 cells/microl or <500 cells/microl). Duration of HIV infection (>16 years) was comparable. Peripheral blood mononuclear cell were stimulated with gag+env or with cytomegalovirus peptides. Activated T cells (Ki67(+)), Treg lymphocytes (CD4(+)/CD25high/Foxp3+), divided into naive and activated cells based on PD1 expression, interleukin (IL)-10 and transforming growth factor (TGF)-beta production, annexin V, activation of caspases 8 and 9, Toll-like receptor (TLR)2 and TLR4 expression on immune cells, and plasma lipopolysaccharide (LPS) concentration were analyzed.

RESULTS

CD4(+)/Ki67(+) T cells; plasma LPS; total, naive, and activated Treg; TLR2-expressing and TLR4-expressing Treg; IL-10 production; and early and late apoptotic CD4 T cells, were significantly increased in patients with undetectable viremia and CD4 cell counts less than 500 cells/microl after more than 7 years of ART. As previously shown, CD4 nadir were also lower in these individuals. Immune activation, LPS concentration, Treg, and degree of apoptosis were negatively correlated with CD4 cell counts.

CONCLUSION

Lack of CD4 recovery in individuals in whom ART suppresses HIV replication is associated with complex immune alterations. Immune activation, likely driven by altered gut permeability and resulting in augmented Treg activity could play a pivotal role in this process.

Pretreatment levels of soluble cellular receptors and interleukin-6 are associated with HIV disease progression in subjects treated with highly active antiretroviral therapy

BACKGROUND

To identify inflammatory pathways that may contribute to the pathogenesis of human immunodeficiency virus (HIV) disease, we explored associations between AIDS or death and different inflammatory markers, including selected soluble tumor necrosis factor superfamily receptors (sTNFRs) and ligands, interleukin (IL)-6, and CD8 T cell activation, in individuals treated with highly active antiretroviral therapy (HAART).

METHODS

A case-control study of subjects in AIDS Clinical Trials Group (ACTG) protocols 384 and 5015, who were matched according to the CD4 cell count and plasma viral load at baseline, was performed using conditional logistic regression.

RESULTS

Higher pretreatment concentrations of sTNFR-1, sCD27, sCD40L, and plasma IL-6 were associated with a new AIDS-defining illness or death in separate models adjusted for age, sex, hemoglobin, and the latest CD4 cell counts. In additional models that excluded case patients with opportunistic infections, sTNFR-1, sCD27, and sCD40L were each associated with a new AIDS-defining malignancy or death that developed at a median of 51 weeks after initiation of HAART, by which time the majority of subjects had a CD4 cell count of >200 cells/cm(3) and had achieved a plasma viral load of <50 copies/mL.

CONCLUSION

These data are compatible with a model in which these soluble inflammatory markers identify pathways that may contribute to the pathogenesis of HIV disease progression, pathways that might not be a direct consequence of ongoing HIV type 1 replication.

Relationship between a frailty-related phenotype and progressive deterioration of the immune system in HIV-infected men

CONTEXT

Immunological similarities have been noted between HIV-infected individuals and older HIV-negative adults. Immunologic alterations with aging have been noted in frailty in older adults, a clinical syndrome of high risk for mortality and other adverse outcomes. Using a frailty-related phenotype (FRP), we investigated in the Multicenter AIDS Cohort Study whether progressive deterioration of the immune system among HIV-positive individuals independently predicts onset of FRP.

METHODS

FRP was evaluated semiannually in 1046 HIV-infected men from 1994 to 2005. CD4 T-cell count and plasma viral load were evaluated as predictors of FRP by logistic regression (generalized estimating equations), adjusting for age, ethnicity, educational level, AIDS status, and treatment era [pre-highly active antiretroviral therapy (HAART) (1994-1995) and HAART (1996-1999 and 2000-2005)].

RESULTS

Adjusted prevalences of FRP remained low for CD4 T-cell counts >400 cells per cubic millimeter and increased exponentially and significantly for lower counts. Results were unaffected by treatment era. After 1996, CD4 T-cell count, but not plasma viral load, was independently associated with FRP.

CONCLUSIONS

CD4 T-cell count predicted the development of a FRP among HIV-infected men, independent of HAART use. This suggests that compromise of the immune system in HIV-infected individuals contributes to the systemic physiologic dysfunction of frailty.

Premature aging of T cells is associated with faster HIV-1 disease progression

OBJECTIVE

To determine if untreated HIV-1 infection and progression is associated with premature aging of memory CD8 and CD4 T cells and naive CD4 T cells.

METHODS

Twenty HIV-1-infected fast progressors and 40 slow progressors were included in our study, using risk set sampling. The expression of cell surface markers reflecting the differentiation stages of lymphocytes was measured using flow cytometry analyses performed on cryopreserved peripheral blood mononuclear cells.

RESULTS

We found that HIV-1 disease progression is associated with a decreased CD28 median florescence intensity on CD4 and CD8 T cells; an increased proportion of intermediate- and late-differentiated CD8 T cells and a decreased CD31 median florescence intensity on naive CD4 T cells of recent thymic origin. A selective depletion of peripherally expanded naive CD4 T cells was found to be associated with HIV-1 infection but not with HIV-1 disease progression.

CONCLUSIONS

The overall change during HIV-1 infection and progression is associated with a shift in the T-cell population toward an aged conformation, which may be further compromised by impaired renewal of the less-differentiated CD4 T-cell population. Our results suggest that HIV-1 infection induces an accelerated aging of T lymphocytes, which is associated with the clinical progression to AIDS and death.

Incomplete reconstitution of T cell subsets on combination antiretroviral therapy in the AIDS Clinical Trials Group protocol 384

BACKGROUND

Initiation of combination antiretroviral therapy (ART) results in higher total CD4 cell counts, a surrogate for immune reconstitution. Whether the baseline CD4 cell count affects reconstitution of immune cell subsets has not been well characterized.

METHODS

Using data from 978 patients (621 with comprehensive immunological assessments) from the AIDS [Acquired Immunodeficiency Syndrome] Clinical Trials Group protocol 384, a randomized trial of initial ART, we compared reconstitution of CD4(+), CD4(+) naive and memory, CD4(+) activation, CD8(+), CD8(+) activation, B, and natural killer cells among patients in different baseline CD4(+) strata. Reference ranges for T cell populations in control patients negative for human immunodeficiency virus (HIV) infection were calculated using data from AIDS Clinical Trials Group protocol A5113.

RESULTS

Patients in the lower baseline CD4(+) strata did not achieve total CD4(+) cell counts similar to those of patients in the higher strata during 144 weeks of ART, although CD4(+) cell count increases were similar. Ratios of CD4(+) naive-memory cell counts and CD4(+):CD8(+) cell counts remained significantly reduced in patients with lower baseline CD4(+) cell counts (

CONCLUSIONS

After nearly 3 years of ART, T cell subsets in patients with baseline CD4(+) cell counts >350 cells/mm(3) achieved or approached the reference range those of control individuals without HIV infection. In contrast, patients who began ART with Collapse

Key Words Collapse

MESH Headings

• Acquired Immunodeficiency Syndrome/drug therapy
• Acquired Immunodeficiency Syndrome/immunology
• Adult
• Antiretroviral Therapy, Highly Active
• B-Lymphocytes/immunology
• CD4 Lymphocyte Count
• CD4-CD8 Ratio
• Female
• Humans
• Killer Cells, Natural/immunology
• Male
• Middle Aged
• T-Lymphocyte Subsets/immunology

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Grants

• AI25879 NIAID NIH HHS
• AI066992 NIAID NIH HHS
• K01 AI062435-02 NIAID NIH HHS
• R01 AI066992 NIAID NIH HHS
• U01 AI038858 NIAID NIH HHS
• AI27659 NIAID NIH HHS
• AI38855 NIAID NIH HHS
• IP30AI060354 NIAID NIH HHS
• U01 AI025879 NIAID NIH HHS
• K01 AI062435 NIAID NIH HHS
• AI27666 NIAID NIH HHS
• AI38858 NIAID NIH HHS
• K01 AI062435-04 NIAID NIH HHS
• U01 AI038855 NIAID NIH HHS
• K01 AI062435-03 NIAID NIH HHS
• K01AI062435 NIAID NIH HHS
• U01 AI027666 NIAID NIH HHS
• K01 AI062435-01A1 NIAID NIH HHS
• U01 AI027659 NIAID NIH HHS
• P30 AI060354 NIAID NIH HHS

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Affiliation(s)

Gregory K Robbins Infectious Diseases Unit, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
John G Spritzler
Ellen S Chan
David M Asmuth
Rajesh T Gandhi
Benigno A Rodriguez
Gail Skowron
Paul R Skolnik
Robert W Shafer
Richard B Pollard

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The effect of aging on T-regulatory cell frequency in HIV infection

T-regulatory cell (T-reg) frequency is increased in HIV infection and with aging. We evaluated the effect of age on total, memory and naïve T-reg percentages in untreated HIV infection. Older HIV(+) subjects had a total T-reg percent that is 2.8% (p=0.02) higher than among younger HIV(+), older HIV(-) and younger HIV(-) subjects. In HIV(+) subjects, the total T-reg percentage is inversely correlated with the lymphocyte proliferative responses to tetanus (r=-0.45, p=0.002) and Candida (r=-0.43, p=0.003) antigens. Similar correlations were seen between memory T-reg percentages and the lymphocyte proliferative response to tetanus and Candida in HIV(+) subjects. T-reg percentages did not correlate consistently with markers of immune activation. T-reg percentages are increased in the older HIV(+) population and may play a role in the accelerated disease progression seen in older HIV-infected persons.

Aging and infectious diseases: workshop on HIV infection and aging: what is known and future research directions

Highly active antiretroviral treatment has resulted in dramatically increased life expectancy among patients with HIV infection who are now aging while receiving treatment and are at risk of developing chronic diseases associated with advanced age. Similarities between aging and the courses of human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome suggest that HIV infection compresses the aging process, perhaps accelerating comorbidities and frailty. In a workshop organized by the Association of Specialty Professors, the Infectious Diseases Society of America, the HIV Medical Association, the National Institute on Aging, and the National Institute on Allergy and Infectious Diseases, researchers in infectious diseases, geriatrics, immunology, and gerontology met to review what is known about HIV infection and aging, to identify research gaps, and to suggest high priority topics for future research. Answers to the questions posed are likely to help prioritize and balance strategies to slow the progression of HIV infection, to address comorbidities and drug toxicity, and to enhance understanding about both HIV infection and aging.

CD38 expression on CD8 T cells has a weak association with CD4 T-cell recovery and is a poor marker of viral replication in HIV-1-infected patients on antiretroviral therapy

OBJECTIVE

The aim of the study was to determine whether the expression of CD38 on CD8 T cells can identify patients with virological failure on antiretroviral therapy (ART).

DESIGN

This was a cross-sectional study of patients attending a single HIV clinic in London.

METHODS

The expression of CD38 on CD8 T cells was assessed using a biologically calibrated flow cytometry protocol. Patients were characterized by lymphocyte subset and viral load measurements. Characteristics including historical CD4 T cell counts, therapeutic history, co-infections and demographics were obtained from medical records.

RESULTS

Elevated levels of CD8 CD38(high) T cells were found in HIV-1-infected patients who failed to suppress viral replication with ART; however, this parameter lacked sufficient sensitivity and specificity to replace viral load testing in assessing the efficacy of ART. Increased levels of CD8 CD38(high) cells were associated with reduced CD4 T cell counts in HIV-1-infected patients on ART after correcting for known determinants of CD4 T-cell recovery.

CONCLUSIONS

The expression of CD38 on CD8 T cells lacks sufficient sensitivity and specificity to be used as a surrogate marker for viral load to monitor HIV-1 infection. T-cell activation is associated with reduced CD4 T-cell reconstitution in patients receiving ART.

Long-term safety and efficacy results of once-daily emtricitabine-based highly active antiretroviral therapy regimens in human immunodeficiency virus-infected pediatric subjects

OBJECTIVES

The purpose of this work was to obtain long-term safety and efficacy data for antiretroviral regimens containing emtricitabine in HIV-infected pediatric subjects and confirm that a pediatric dose of 6 mg/kg once daily would provide steady-state emtricitabine concentrations comparable to those observed in adults given 200 mg of emtricitabine once daily.

PATIENTS AND METHODS

HIV-infected subjects between 3 months and 16 years of age were enrolled, including 71 antiretroviral-naïve subjects and 45 antiretroviral-experienced subjects. Naive subjects received emtricitabine plus stavudine plus lopinavir or ritonavir. Experienced subjects replaced the lamivudine in their existing regimens with emtricitabine. Tolerance, safety, disease progression, and virologic and immunologic responses were evaluated.

RESULTS

The Kaplan-Meier probability of persistent virologic response in the intent-to-treat population through week 164 at < or = 400 copies per mL and < or = 50 copies per mL was 74% and 62%, respectively. Three subjects (3%) discontinued the study for adverse events, 8 (7%) for virologic failure, and 1 died through a median follow-up of 164 weeks. The annualized incidence rate of grade 3 to 4 adverse events and grade 3 to 4 laboratory abnormalities was 6% and 3%, respectively. The annualized incidence rate of serious adverse events was 9%, with 1% attributed as related to emtricitabine. Genotypic analysis showed the emergence of the M184V mutation in 4 of the 15 subjects who experienced virologic failure through week 164. Pharmacokinetic evaluation demonstrated plasma drug exposures in these children comparable to adults receiving the approved dose of 200 mg once daily.

CONCLUSIONS

These results demonstrate the safety and efficacy of emtricitabine in pediatric patients. They also support that the safety and efficacy profile of emtricitabine in children is similar to that demonstrated in adults.

Immune activation and inflammation in HIV-1 infection: causes and consequences

Thorough research on HIV is progressively enabling us to understand the intricate mechanisms that link HIV-1 infection to the onset of immunodeficiency. The infection and depletion of CD4(+) T cells represent the most fundamental events in HIV-1 infection. However, in recent years, the role played by chronic immune activation and inflammation in HIV pathogenesis has become increasingly apparent: quite paradoxically, immune activation levels are directly associated with HIV-1 disease progression. In addition, HIV-1-infected patients present intriguing similarities with individuals of old age: their immune systems are characterized by a loss of regenerative capacity and an accumulation of ageing T cells. In this review, we discuss the potential reasons for the establishment of sustained immune activation and inflammation from the early stages of HIV-1 infection, as well as the long-term consequences of this process on the host immune system and health. A simplified model of HIV pathogenesis is proposed, which links together the three major facets of HIV-1 infection: the massive depletion of CD4(+) T cells, the paradoxical immune activation and the exhaustion of regenerative capacity.

HIV and menopause: a review

The use of highly active antiretroviral therapy (HAART) has resulted in dramatic reductions in morbidity and mortality of HIV infected individuals. With increasing life expectancy, a growing population of women will experience menopausal transitions while infected with HIV. Changes associated with menopause may affect HIV disease progression, and HIV-infected women may experience menopause in a different way from that of uninfected women. Age at natural menopause among non-HIV-infected white and Hispanic women is on the average 51 years, and that of African American women is 49 years. Several studies have shown that the mean age of menopause in HIV-infected women is 47-48 years. This is likely due to factors other than HIV infection that predict early menopause, such as drug use, smoking, and low socioeconomic status. It may be difficult to separate out HIV symptoms from menopausal symptoms. The additive effects of menopause, HIV infection, and HAART on changes involving bone, lipid, and glucose metabolism need further investigation. Likewise, there is a need for a better understanding of the prevalence and manifestations of depression among these women.

HIV infection in the elderly

In the US, an estimated 1 million people are infected with HIV, although one-third of this population are unaware of their diagnosis. While HIV infection is commonly thought to affect younger adults, there are an increasing number of patients over 50 years of age living with the condition. UNAIDS and WHO estimate that of the 40 million people living with HIV/AIDS in the world, approximately 2.8 million are 50 years and older. With the introduction of highly active antiretroviral therapy (HAART) in the mid-1990s, survival following HIV diagnosis has risen dramatically and HIV infection has evolved from an acute disease process to being managed as a chronic medical condition. As treated HIV-infected patients live longer and the number of new HIV diagnoses in older patients rise, clinicians need to be aware of these trends and become familiar with the management of HIV infection in the older patient. This article is intended for the general clinician, including geriatricians, and will review epidemiologic data and HIV treatment as well as provide a discussion on medical management issues affecting the older HIV-infected patient.