Recent studies suggest that HIV-specific antibody-dependent cell-mediated cytotoxicity (ADCC) antibodies contribute to protective immunity against HIV. An important characteristic of future HIV vaccines will, therefore, be the ability to stimulate production of these antibodies in both men and women. Early studies suggest that men may have a better ADCC antibody response against HIV than women. Our objective was to determine whether men and women differ with respect to their ADCC response to HIV-1 gp120. HIV-positive, asymptomatic untreated men and women were matched for race, age, CD4+ T cell number, HIV-1 viral load, and treatment and HIV-1 gp120 ADCC antibody titers were compared. A standard 51Cr-release assay was used to determine HIV-1 gp120 ADCC antibody titers in HIV-1-seropositive individuals from the Multicenter AIDS Cohort Study (MACS; n=32) and the Women's Interagency HIV Study (WIHS; n=32). Both sexes had high ADCC titers against HIV-1 gp120: 34.4% (n=11) and 40.6% (n=13) of men and women, respectively, had titers of 10,000; 62.5% (n=20) and 56.3% (n=18) had titers of 100,000. Groups did not differ in percent specific release (% SR), lytic units (LU), correlations of titer to viral load, or titer to CD4+ T cells in men or women. Both groups also had similar cross-clade ADCC antibody responses (p>0.5 for % SR and LU). Comparable groups of asymptomatic HIV-1-infected men and women had comparable HIV-1 gp120 ADCC antibodies. Both sexes had significant cross-clade reactivity. Differences between men and women may become evident as disease progresses; this should be evaluated at later stages of HIV-1 infection.
Antiretroviral regimens (ART) changes occur frequently among HIV-infected persons. Duration and type of initial highly active antiretroviral therapy (HAART) and factors associated with regimen switching were evaluated in the Multicenter AIDS cohort Study.
Participants were classified according to the calendar period of HAART initiation: T1 (1996-2001), T2 (2002-2005) and T3 (2006-2009). Kaplan Meier curves depicted time from HAART initiation to first regimen changes within 5.5 years. Cox proportional hazards regression models were used to examine factors associated with time to switching.
Of 1009 participants, 796 changed regimen within 5.5 years after HAART initiation. The percentage of participants who switched declined from 85% during T1 to 49 % in T3., The likelihood of switching in T3 decreased by 50% (p<0.01) compared to T1 after adjustment for pre-HAART ART use, age, race and CD4 count. Incomplete HIV suppression decreased over time (p<0.01) but predicted switching across all time periods. Lower HAART adherence (≤ 95% of prescribed doses) was predictive of switching only in T1. In T2, central nervous system symptoms predicted switching (RH = 1.7, p= 0.012). Older age at HAART initiation was associated with increased switching in T1 (RH=1.03 per year increase) and decreased switching in T2 (RH = 0.97 per year increase).
During the first 15 years of the HAART era, initial HAART regimen duration lengthened and regimen discontinuation rates diminished. Both HIV RNA non-suppression and poor adherence predicted switching prior to 2001 while side effects that were possibly ART-related were more prominent during T2.
In the context of HIV, the initiation of effective antiretroviral therapy (ART) has been found to increase the risk of dyslipidemia in HIV-infected individuals, and dyslipidemia has been found to be a risk factor for kidney disease in the general population. Therefore, we examined changes in lipid profiles in HIV-infected men following ART initiation and the association with future kidney dysfunction. HIV-infected men from the Multicenter AIDS Cohort Study initiating ART between December 31, 1995 and September 30, 2011 with measured lipid and serum creatinine values pre-ART and post-ART were selected. The associations between changes in total cholesterol or high-density lipoprotein following ART initiation and the estimated change in glomerular filtration rate (eGFR) over time were assessed using piecewise linear mixed effects models. There were 365 HIV-infected men who contributed to the analysis. In the adjusted models, at 3 years post-ART, those with changes in total cholesterol >50 mg/dl had an average decrease in eGFR of 2.6 ml/min/1.73 m2 per year (p<0.001) and at 5 years post-ART, the average decrease was 2.4 ml/min/1.73 m2 per year (p=0.008). This decline contrasted with the estimates for those with changes in total cholesterol ≤50 mg/dl: 1.4 ml/min/1.73 m2 decrease per year (p<0.001) and 0.1 ml/min/1.73 m2 decrease per year (p=0.594) for the same time periods, respectively. Large decreases in high-density lipoprotein (a decline of greater than 5 mg/dl) were not associated with declines in eGFR. These results indicate that large ART-related increases in total cholesterol may be a risk factor for kidney function decline in HIV-infected men. Should these results be generalizable to the broader HIV population, monitoring cholesterol changes following the initiation of ART may be important in identifying HIV-infected persons at risk for kidney disease.
To compare the proportion, timing and hazards of non-AIDS death and AIDS death among men and women who initiated HAART at different CD4+ cell counts to mortality risks of HIV-uninfected persons with similar risk factors.
Prospective cohort studies.
We used parametric mixture models to compare proportions of AIDS and non-AIDS mortality and ages at death, and multivariable Cox models to compare cause-specific hazards of mortality, across levels of CD4+ cell count at HAART initiation (≤200 cells/μl: ‘late’, 201–350 cells/μl: ‘intermediate’, >350 cells/μl: ‘early’) and with HIV-uninfected individuals from the Multicenter AIDS Cohort Study and the Women’s Interagency HIV Study. We used multiple imputation methods to address lead-time bias in sensitivity analysis.
Earlier initiators were more likely to die of non-AIDS causes (early: 78%, intermediate: 74%, late: 49%), and at older ages (median years 72, 69, 66), relative to later initiators. Estimated median ages at non-AIDS death for each CD4+ cell count category were lower than that estimated for the HIV-uninfected group (75 years). In multivariable analysis, non-AIDS death hazard ratios relative to early initiators were 2.15 for late initiators (P < 0.01) and 1.66 for intermediate initiators (P = 0.01); AIDS death hazard ratios were 3.26 for late initiators (P <0.01) and 1.20 for intermediate initiators (P = 0.28). Strikingly, the adjusted hazards for non-AIDS death among HIV-uninfected individuals and early initiators were nearly identical (hazard ratio 1.01). Inferences were unchanged after adjustment for lead-time bias.
Results suggest the possibility of reducing the risk of non-AIDS mortality among HIV-infected individuals to approximate that faced by comparable HIV-uninfected individuals.
antiretroviral therapy; bias; CD4+ cell count; cohort studies; competing risks; mortality; statistical
Allotypes of the natural killer (NK) cell receptor KIR3DL1 vary in both NK cell expression patterns and inhibitory capacity upon binding to their ligands, HLA-B Bw4 molecules, present on target cells. Using a sample size of over 1,500 human immunodeficiency virus (HIV)+ individuals, we show that various distinct allelic combinations of the KIR3DL1 and HLA-B loci significantly and strongly influence both AIDS progression and plasma HIV RNA abundance in a consistent manner. These genetic data correlate very well with previously defined functional differences that distinguish KIR3DL1 allotypes. The various epistatic effects observed here for common, distinct KIR3DL1 and HLA-B Bw4 combinations are unprecedented with regard to any pair of genetic loci in human disease, and indicate that NK cells may have a critical role in the natural history of HIV infection.
To test the predictive accuracy of the Framingham Risk Score for Stroke (FRS-S) in HIV-infected (HIV+) vs HIV-uninfected (HIV−) men.
The Multicenter AIDS Cohort Study (MACS) is an ongoing prospective study of HIV+ and HIV− men who have sex with men (MSM) enrolled in 4 US cities. We ascertained all reported stroke events during a recent 15-year timeframe (July 1, 1996 to June 30, 2011) among 3,945 participants (1,776 HIV+ and 2,169 HIV−). For those with strokes, FRS-S were calculated 10 years before the stroke event and assessed according to HIV status.
A total of 114 stroke events occurred, including 57 HIV+ and 37 HIV− participants with first-ever strokes and 19 fatal strokes. The incidence of first-ever stroke was 1.7/1,000 person-years among HIV− and 3.3/1,000 person-years among HIV+ participants. Among those with strokes, HIV+ participants were younger than HIV− participants (median age 51.3 vs 61.8 years, p < 0.0001). For these men with stroke, the average 10-year risk of stroke was higher for HIV− MSM (6.6% [range 3%–26%] vs 4.9% for HIV+ MSM [range 0%–15%], p < 0.04). Traditional risk factors for stroke were similar among the Framingham cohort and the MACS HIV+ and HIV− participants.
FRS-S prediction was systematically different in HIV+ vs HIV− men with stroke events. The FRS-S underestimates the long-term risk of stroke in HIV+ men.
Parametric and semiparametric competing risks methods were used to estimate proportions, timing, and predictors of acquired immune deficiency syndrome (AIDS)-related and non-AIDS-related mortality among individuals both positive and negative for the human immunodeficiency syndrome (HIV) in the Multicenter AIDS Cohort Study (MACS) and Women's Interagency HIV Study (WIHS) from 1984 to 2008 and 1996 to 2008, respectively. Among HIV-positive MACS participants, the proportion of deaths unrelated to AIDS increased from 6% before the introduction of highly active antiretroviral therapy (HAART) (before 1996) to 53% in the HAART era (P < 0.01); the median age of persons who died from non-AIDS-related causes after age 35 years increased from 49.0 to 66.0 years (P < 0.01). In both cohorts during the HAART era, median ages at time of non-AIDS-related death were younger for HIV-positive individuals than for comparable HIV-negative individuals (8.7 years younger in MACS (P < 0.01) and 7.6 years younger in WIHS (P < 0.01)). In a multivariate proportional cause-specific hazards model, unemployment (for non-AIDS death, hazard ratio (HR) = 1.8; for AIDS death, HR = 2.3), depression (for non-AIDS death, HR = 1.4; for AIDS death, HR = 1.4), and hepatitis B or C infection (for non-AIDS death, HR = 1.8, for AIDS death; HR = 1.4) were significantly (P < 0.05) associated with higher hazards of both non-AIDS and AIDS mortality among HIV-positive individuals in the HAART era, independent of study cohort. The results illuminate the changing face of mortality among the growing population infected with HIV.
acquired immunodeficiency syndrome; antiretroviral therapy, highly active; cohort studies; competing risks; HIV; mixture model; mortality; proportional hazards models
Cryopreservation of peripheral blood mononuclear cells (PBMC) allows assays of cellular function and phenotype to be performed in batches at a later time on PBMC at a central laboratory to minimize assay variability. The Multicenter AIDS Cohort Study (MACS) is an ongoing prospective study of the natural and treated history of human immunodeficiency virus (HIV) infection that stores cryopreserved PBMC from participants two times a year at four study sites. In order to ensure consistent recovery of viable PBMC after cryopreservation, a quality assessment program was implemented and conducted in the MACS over a 6-year period. Every 4 months, recently cryopreserved PBMC from HIV-1-infected and HIV-1-uninfected participants at each MACS site were thawed and evaluated. The median recoveries of viable PBMC for HIV-1-infected and -uninfected participants were 80% and 83%, respectively. Thawed PBMC from both HIV-1-infected and -uninfected participants mounted a strong proliferative response to phytohemagglutinin, with median stimulation indices of 84 and 120, respectively. Expression of the lymphocyte surface markers CD3, CD4, and CD8 by thawed PBMC was virtually identical to what was observed on cells measured in real time using whole blood from the same participants. Furthermore, despite overall excellent performance of the four participating laboratories, problems were identified that intermittently compromised the quality of cryopreserved PBMC, which could be corrected and monitored for improvement over time. Ongoing quality assessment helps laboratories improve protocols and performance on a real-time basis to ensure optimal cryopreservation of PBMC for future studies.
The human APOBEC3 family of cytidine deaminases provides intrinsic immunity to retroviral infection. A naturally occurring 29.5-kb deletion removes the entire APOBEC3B gene. We examined the impact of the APOBEC3B gene deletion in >4000 individuals from five HIV-1 natural history cohorts. The hemizygous genotype had no effect on either infection or progression. However, the homozygous deletion was significantly associated with unfavorable outcomes for HIV-1 acquisition (OR=7.37, P=0.024), progression to AIDS (RH = 4.01, P=0.03), and viral set-point (P=0.04). These findings suggest that the loss of APOBEC3B may increase host susceptibility to HIV-1/AIDS and warrant further study.
Although HLA-B*57 (B57) is associated with slow progression to disease following HIV-1 infection, B57 heterozygotes display a wide spectrum of outcomes, including rapid progression, viremic slow progression, and elite control. Efforts to identify differences between B57-positive (B57+) slow progressors and B57+ rapid progressors have largely focused on cytotoxic T lymphocyte (CTL) phenotypes and specificities during chronic stages of infection. Although CTL responses in the early months of infection are likely to be the most important for the long-term rate of HIV-1 disease progression, few data on the early CTL responses of eventual slow progressors have been available. Utilizing the Multicenter AIDS Cohort Study (MACS), we retrospectively examined the early HIV-1-specific CTL responses of 14 B57+ individuals whose time to development of disease ranged from 3.5 years to longer than 25 years after infection. In general, a greater breadth of targeting of epitopes from structural proteins, especially Gag, as well as of highly conserved epitopes from any HIV-1 protein, correlated with longer times until disease. The single elite controller in the cohort was an outlier on several correlations of CTL targeting and time until disease, consistent with reports that elite control is typically not achieved solely by protective HLA-mediated CTLs. When targeting of individual epitopes was analyzed, we found that early CTL responses to the IW9 (ISPRTLNAW) epitope of Gag, while generally subdominant, correlated with delayed progression to disease. This is the first study to identify early CTL responses to IW9 as a correlate of protection in persons with HLA-B*57.
To review the incidence of respiratory conditions and their effect on mortality in HIV-infected and uninfected individuals prior to and during the era of highly active antiretroviral therapy (HAART).
Two large observational cohorts of HIV-infected and HIV-uninfected men (Multicenter AIDS Cohort Study [MACS]) and women (Women’s Interagency HIV Study [WIHS]), followed since 1984 and 1994, respectively.
Adjusted odds or hazards ratios for incident respiratory infections or non-infectious respiratory diagnoses, respectively, in HIV-infected compared to HIV-uninfected individuals in both the pre-HAART (MACS only) and HAART eras; and adjusted Cox proportional hazard ratios for mortality in HIV-infected persons with lung disease during the HAART era.
Compared to HIV-uninfected participants, HIV-infected individuals had more incident respiratory infections both pre-HAART (MACS, odds ratio [adjusted-OR], 2.4; 95% confidence interval [CI], 2.2–2.7; p<0.001) and after HAART availability (MACS, adjusted-OR, 1.5; 95%CI 1.3–1.7; p<0.001; WIHS adjusted-OR, 2.2; 95%CI 1.8–2.7; p<0.001). Chronic obstructive pulmonary disease was more common in MACS HIV-infected vs. HIV-uninfected participants pre-HAART (hazard ratio [adjusted-HR] 2.9; 95%CI, 1.02–8.4; p = 0.046). After HAART availability, non-infectious lung diseases were not significantly more common in HIV-infected participants in either MACS or WIHS participants. HIV-infected participants in the HAART era with respiratory infections had an increased risk of death compared to those without infections (MACS adjusted-HR, 1.5; 95%CI, 1.3–1.7; p<0.001; WIHS adjusted-HR, 1.9; 95%CI, 1.5–2.4; p<0.001).
HIV infection remained a significant risk for infectious respiratory diseases after the introduction of HAART, and infectious respiratory diseases were associated with an increased risk of mortality.
Purpose of Review
Highly active antiretroviral therapy (HAART) use has markedly reduced AIDS-related mortality and opportunistic illness. With improved survival, cardiovascular disease (CVD) has emerged as an important non-infectious chronic co-morbidity among antiretroviral (ARV)-treated HIV-infected persons.
HIV infection can impact CVD and co-morbidiities known to increase CVD risk. Untreated HIV can cause proatherogenic elevations in serum lipids. Chronic HIV viremia results in increases in systemic inflammation, hypercoagulation, and reductions in endovascular reactivity, all of which are at least partially reversible with virally suppressive HAART. Chronic T cell activation can also result in adverse vascular effects. Use of some ARV drugs can impact CVD risk by causing pro-atherogenic serum lipid elevations, induction of insulin resistance, increases in visceral adiposity or subcutaneous fat loss. Abacavir use may increase myocardial infarction risk by reducing vascular reactivity and/or increasing platelet activation. Traditional risk factors such as advancing age, smoking, hyperlipidemia, and hypertension remain important predictors of CVD among HAART-treated HIV-infected persons.
HIV in the HAART era is a chronic manageable condition. CVD is an important cause of morbidity among HIV-infected persons. Untreated HIV can increase CVD risk in several ways and these effects are at least partially reversible with successful treatment. Use of specific ARV’s can adversely impact CVD risk but the multiple long-term benefits of chronic HIV suppression and immune reconstitution achievable with potent HAART outweigh the adverse impact upon CVD risks that they may have. Standard CVD screening and risk-reducing interventions should be routinely undertaken for HIV-infected persons.
Cardiovascular disease in HIV infection; Inflammation; hypercoagulation; vascular functioning; Effects of antiretroviral drugs; Hyperlipidemia
In the general population, frailty, a late stage of the aging process, predicts mortality. We investigated whether manifesting a previously defined frailty-related phenotype (FRP) before initiating highly active antiretroviral therapy (HAART) affects the likelihood of developing clinical AIDS or mortality after HAART initiation.
Among 596 HIV-infected men in the Multicenter AIDS Cohort Study whose date of HAART initiation was known within ±6 months and who had an assessable FRP status within 3 years before HAART, survival analyses were performed to assess the effect of FRP manifestation on clinical AIDS or death after HAART.
In men free of AIDS before HAART, AIDS or death after HAART occurred in 13/36 (36%) men who exhibited the FRP before HAART but only in 69/436 (16%) men who did not (hazard ratio = 2.6; 95% confidence interval = 1.4–4.6; p < .01). After adjusting for age, ethnicity, education, nadir CD4+ T-cell count, peak HIV viral load, and hemoglobin in the 3 years before HAART, having the FRP at >25% of visits in the 3 years before HAART significantly predicted AIDS or death (adjusted hazard ratio = 3.8; 95% confidence interval = 1.9–7.9; p < .01). Results were unchanged when the analysis was restricted to the 335 AIDS-free men who were HAART responders, to the 124 men who had AIDS at HAART initiation, or to the subsets of men for whom indices of liver and kidney function could be taken into account.
Having a persistent frailty-like phenotype before HAART initiation predicted a worse prognosis after HAART, independent of known risk factors.
HIV; Aging; Frailty; HAART response; Survival analysis
The heterogeneity of CD4+ T-cell counts and HIV-1 RNA at 5-12 years after the initiation of highly active antiretroviral therapy (HAART) remains largely uncharacterized.
In the Multicenter AIDS Cohort Study, 614 men who initiated HAART contributed data 5-12 years subsequently. Multivariate regression was used to evaluate the predictors of CD4+ counts and HIV-1 RNA levels.
At 5-12 years post-HAART, the median CD4+ T-cell count was 586 (inter quartile range (IQR): 421-791) cells/μl and 78% of the HIV-1 RNA measurements were undetectable. Higher CD4+ T-cell counts 5-12 years post-HAART were predicted by higher CD4+ T-cell counts and higher total lymphocyte count pre-HAART, lack of hepatitis B or C virus co-infections, and greater CD4+ T-cell change as well as suppressed HIV-1 RNA in the first 5 years after starting HAART. Older men (≥50 years) with 351-500 CD4+ cells/μl at HAART initiation had adjusted mean CD4+ T-cell count of 643 cells/μl at 10-12 years post-HAART, which was similar to the adjusted mean CD4+ T-cell count (670 cells/μl, p=0.45) in this period for younger men starting HAART with lower CD4+ T-cell counts. HIV-1 RNA suppression in the first 5 years post-HAART predicted subsequent viral suppression.
Immunological and virological responses in the first five years post-HAART predicted subsequent CD4+ T-cell counts and HIV-1 RNA levels. The association between age and subsequent CD4+ T-cell count supports incorporating age in guidelines for use of HAART.
CD4+ T-cells; HIV-1 RNA; HAART; response; age effects
Purpose of Review
Highly Active Antiretroviral Therapy (HAART) has resulted in a marked decrease in AIDS-related conditions and death. With improved survival, cardiovascular disease (CVD), hepatic, renal disease and non-AIDS related cancers represent an increasing burden for HIV infected individuals.
HIV Associated Nephropathy (HIVAN), acute renal injury, HAART, and co-morbid conditions such as Hepatitis C, hypertension and diabetes are among the multiple causes of renal disease. In HIVAN there is incomplete understanding of the interaction of the virus with renal cellsand the host genetics leading to susceptibility to this form of renal dysfunction. There is agreement that a baseline estimate of glomerular filtration (eGFR) should be obtained and that renal function should be monitored during antiretroviral therapy. There is, however no agreement as to the most accurate method of estimating GFR. Renal transplantation has emerged as a feasible and successful modality of management of end stage renal disease (ESRD) in HIV infected individuals.
Kidney disease represents an increasing concern in the care of HIV infected persons although there are questions remaining regarding the pathophysiology of HIVAN. Transplantation, however, can be carried out safely in infected persons with ESRD.
HIV Associated Nephropathy; Estimates of Glomerular filtration; Renal transplantation of HIV infected patients with end stage renal disease; Effects of anitiretroviral drugs upon renal function
Chromosome 3p21–22 harbors two clusters of chemokine receptor genes, several of which serve as major or minor coreceptors of HIV-1. Although the genetic association of CCR5 and CCR2 variants with HIV-1 pathogenesis is well known, the role of variation in other nearby chemokine receptor genes remain unresolved. We genotyped exonic single nucleotide polymorphisms (SNPs) in chemokine receptor genes: CCR3, CCRL2, and CXCR6 (at 3p21) and CCR8 and CX3CR1 (at 3p22), the majority of which were non-synonymous. The individual SNPs were tested for their effects on disease progression and outcomes in five treatment-naïve HIV-1/AIDS natural history cohorts. In addition to the known CCR5 and CCR2 associations, significant associations were identified for CCR3, CCR8, and CCRL2 on progression to AIDS. A multivariate survival analysis pointed to a previously undetected association of a non-conservative amino acid change F167Y in CCRL2 with AIDS progression: 167F is associated with accelerated progression to AIDS (RH = 1.90, P = 0.002, corrected). Further analysis indicated that CCRL2-167F was specifically associated with more rapid development of pneumocystis pneumonia (PCP) (RH = 2.84, 95% CI 1.28–6.31) among four major AIDS–defining conditions. Considering the newly defined role of CCRL2 in lung dendritic cell trafficking, this atypical chemokine receptor may affect PCP through immune regulation and inducing inflammation.
Human chemokine receptors are cell surface proteins that may be utilized by HIV-1 for entry into host cells. DNA variation in the HIV-1 major coreceptor CCR5 affects HIV-1 infection and progression. This study comprehensively assesses the role of genetic variation of multiple chemokine receptor genes clustered in the chromosome 3p21 and 3p22 on HIV-1 disease outcomes in HIV-1 natural history cohorts. The multivariate survival analyses identified functional variants that altered disease progression rate in CCRL2, CCR3, and CCR8. CCRL2-F167Y affects the rate to AIDS development through a specific protection against pneumocystis pneumonia (PCP), a common AIDS–defining condition. Our study identified this atypical chemokine receptor CCRL2 as a key factor involved in PCP, possibly through inducing inflammation in the lung.
Background and purpose
Human immunodeficiency virus (HIV)-infected persons taking highly active antiretroviral therapy (HAART) may have an increased risk for cardiovascular-related events, although the underlying mechanism remains unclear. We tested the hypothesis that carotid arterial stiffness was higher among persons taking HAART compared to HAART-naïve and HIV-uninfected persons.
Between 2004 and 2006, we performed high resolution B-mode ultrasound on 2,789 HIV-infected and HIV-uninfected participants of the Women’s Interagency HIV Study (WIHS; 1865 women) and the Multicenter AIDS Cohort Study (MACS; 924 men) and determined carotid arterial distensibility, a direct measure of carotid arterial stiffness. We used generalized estimating equations to evaluate the association between distensibility and HIV infection, CD4+ cell count, and exposure to HAART adjusted for demographic, behavioral, and clinical characteristics.
In multivariable analysis, distensibility was 4.3% lower (95% confidence interval (CI): -7.4% to -1.1%) among HIV-infected versus uninfected participants. Among HIV-infected participants with fewer than 200 CD4+ cells, distensibility was 10.5% lower (95% CI: -14.5% to -6.2%) than that among HIV-uninfected participants, and this effect did not differ significantly by cohort or race. Concurrent HAART use was independently associated with lower distensibility among MACS participants but not among WIHS participants.
Our finding that advanced HIV-related immunosuppression was associated with increased carotid arterial stiffness independent from the effects of traditional atherosclerosis risk factors suggests that the etiologic mechanism underlying reports of an increased cardiovascular disease risk among HIV-infected individuals might involve HIV-related immunosuppression leading to vascular dysfunction and arterial stiffening.
atherosclerosis; cardiovascular disease; carotid arteries; HIV; epidemiology
Background. The compilation of previous genomewide association studies of AIDS shows a major polymorphism in the HCP5 gene associated with both control of the viral load and long-term nonprogression (LTNP) to AIDS.
Methods. To look for genetic variants that affect LTNP without necessary control of the viral load, we reanalyzed the genomewide data of the unique LTNP Genomics of Resistance to Immunodeficiency Virus (GRIV) cohort by excluding “elite controller” patients, who were controlling the viral load at very low levels (<100 copies/mL).
Results. The rs2234358 polymorphism in the CXCR6 gene was the strongest signal (P = 2.5 × 10−7; odds ratio, 1.85) obtained for the genomewide association study comparing the 186 GRIV LTNPs who were not elite controllers with 697 uninfected control subjects. This association was replicated in 3 additional independent European studies, reaching genomewide significance of Pcombined = 9.7 × 10−10. This association with LTNP is independent of the combined CCR2-CCR5 locus and the HCP5 polymorphisms.
Conclusion. The statistical significance, the replication, and the magnitude of the association demonstrate that CXCR6 is likely involved in the molecular etiology of AIDS and, in particular, in LTNP, emphasizing the power of extreme-phenotype cohorts. CXCR6 is a chemokine receptor that is known as a minor coreceptor in human immunodeficiency virus type 1 infection but could participate in disease progression through its role as a mediator of inflammation.
HLA class I polymorphism is known to affect the rate of progression to AIDS after infection with HIV-1. Here we test the consistency of HLA-B allelic effects on progression to AIDS, heterosexual HIV transmission and ‘setpoint’ viral levels.
We used adjusted Cox proportional hazard models in previously published relative hazard (RH) values for the effect of HLA-B alleles on progression to AIDS (n=1089). The transmission study included 303 HIV-1-infected men with hemophilia and their 323 female sex partners (MHCS cohort). Among 259 HIV-1 seroconverters (MACS cohort), HIV RNA levels at ‘setpoint’ were determined in stored plasma samples by a reverse-transcription polymerase chain reaction assay. HLA-B genotyping was performed by sequence-specific-oligonucleotide-hybridization and DNA sequencing.
Several HLA-B alleles showed consistent associations for AIDS risk, infectivity and ‘setpoint’ HIV RNA. HLA-B*35 was associated with more rapid progression to AIDS (RH 1.39; p = 0.008), greater infectivity (OR 3.14; p = 0.002), and higher HIV RNA (p = 0.01), whereas the presence of either B*27 or B*57 associated with slower progression to AIDS (B*27: RH 0.49, p < 0.001; B*57: RH 0.40, p <0.0001), less infectivity (OR 0.22 and 0.31, respectively, though not significant) and lower viral levels (p <0.0001). Importantly, HLA-B polymorphism in female partners was not associated with susceptibility to HIV-1 infection.
HLA-B polymorphisms that affect the risk of AIDS may also alter HIV-1 infectivity, probably through the common mechanism of viral control, but they do not appear to protect against infection in our cohort.
HIV; AIDS; HLA; viral load; HIV transmission; AIDS progression; MHC diversity
The presence of antibody to R7V (anti-R7VAb), a seven-amino acid sequence derived from β2-microglobulin incorporated into HIV-1 virions from the surface of infected cells, has been proposed as an early marker of nonprogressive HIV-1 infection. The present study was undertaken because no prospective studies have tested this hypothesis. Stored samples collected prospectively from 361 HIV-1 seroconverting men in the Multicenter AIDS Cohort Study (0.44–1.53 years after seroconversion) were assayed for the presence or absence of anti-R7VAb, using a standardized ELISA. Using Cox proportional hazards models, crude and adjusted relative hazards (RH) were determined for the following outcomes: (a) clinically defined AIDS, (b) clinically defined AIDS or CD4 T cell count of <200 cells/μl, and (c) death. A total of 143 (39.6%) men had early anti-R7VAb and 218 (60.4%) did not; 192 (53.2%) developed AIDS. At the visit tested, men with anti-R7VAb had significantly lower CD4 T cell counts and higher plasma HIV-1 viral loads than those without antibody. After adjustment for CD4 T cell count, HIV-1 viral load, CCR5 polymorphism, and use of combined antiretroviral therapy, the presence of anti-R7VAb was associated with a higher risk of progression for all outcomes, but not significantly so. Absence of anti-R7VAb was significantly associated with expression of HLA-B*5701 and -B*2705, two alleles associated with slower progression of HIV-1 disease. The early presence of anti-R7VAb in HIV-1 seroconverters was not associated with slower progression of HIV-1 disease.
We attempted to refine the understanding of an association of Y-chromosomal haplogroup I (hg-I) with enhanced AIDS progression that had been previously reported. First, we compared the progression phenotype between hg-I and its phylogenetically closest haplogroup J (hg-J). Then, we took a candidate gene approach resequencing DDX3Y, a crucial autoimmunity gene, in hg-I and other common European Y- chromosome haplogroups looking for functional variants. We extended the genetic analyses to CD24L4 and compared and contrasted the roles of disease based selection, demographic history, and population structure shaping the contemporary genetic landscape of hg-I chromosomes. Our results confirmed and refined the AIDS progression signal to hg-I, though no gene variant was identified that can explain the disease association. Molecular evolutionary and genetic analyses of the examined loci suggested a unique evolutionary history in hg-I, probably shaped by complex interactions of selection, demographic history, and high geographical differentiation leading to the formation of distinct hg-I subhaplogroups that today are associated with HIV/AIDS onset. Clearly, further studies on Y chromosome candidate loci sequencing to discover functional variants and discern the roles of evolutionary factors are warranted.
AIDS progression; CD24L4; DDX3Y; population growth; population structure; selection; Y chromosome
HIV-1-infected adults over the age of 50 years progress to AIDS more rapidly than adults in their twenties or thirties. In addition, HIV-1-infected individuals receiving antiretroviral therapy (ART) present with clinical diseases, such as various cancers and liver disease, more commonly seen in older uninfected adults. These observations suggest that HIV-1 infection in older persons can have detrimental immunological effects that are not completely reversed by ART. As naïve T-cells are critically important in responses to neoantigens, we first analyzed two subsets (CD45RA+CD31+ and CD45RA+CD31-) within the naïve CD4+ T-cell compartment in young (20–32 years old) and older (39–58 years old), ART-naïve, HIV-1 seropositive individuals within 1–3 years of infection and in age-matched seronegative controls. HIV-1 infection in the young cohort was associated with lower absolute numbers of, and shorter telomere lengths within, both CD45RA+CD31+CD4+ and CD45RA+CD31-CD4+ T-cell subsets in comparison to age-matched seronegative controls, changes that resembled seronegative individuals who were decades older. Longitudinal analysis provided evidence of thymic emigration and reconstitution of CD45RA+CD31+CD4+ T-cells two years post-ART, but minimal reconstitution of the CD45RA+CD31-CD4+ subset, which could impair de novo immune responses. For both ART-naïve and ART-treated HIV-1-infected adults, a renewable pool of thymic emigrants is necessary to maintain CD4+ T-cell homeostasis. Overall, these results offer a partial explanation both for the faster disease progression of older adults and the observation that viral responders to ART present with clinical diseases associated with older adults.
Despite thymic involution, the number of naive CD4+ T cells diminishes slowly during aging, suggesting considerable peripheral homeostatic expansion of these cells. To investigate the mechanisms behind, and consequences of, naive CD4+ T cell homeostasis, we evaluated the age-dependent dynamics of the naive CD4+ T cell subsets CD45RA+CD31+ and CD45RA+CD31−. Using both a cross-sectional and longitudinal study design, we measured the relative proportion of both subsets in individuals ranging from 22 to 73 years of age and quantified TCR excision circle content within those subsets as an indicator of proliferative history. Our findings demonstrate that waning thymic output results in a decrease in CD45RA+CD31+ naive CD4+ T cells over time, although we noted considerable individual variability in the kinetics of this change. In contrast, there was no significant decline in the CD45RA+CD31− naive CD4+ T cell subset due to extensive peripheral proliferation. Our longitudinal data are the first to demonstrate that the CD45RA+CD31+CD4+ subset also undergoes some in vivo proliferation without immediate loss of CD31, resulting in an accumulation of CD45RA+CD31+ proliferative offspring. Aging was associated with telomere shortening within both subsets, raising the possibility that accumulation of proliferative offspring contributes to senescence of the naive CD4+ T cell compartment in the elderly. In contrast, we observed retention of clonal TCR diversity despite peripheral expansion, although this analysis did not include individuals over 65 years of age. Our results provide insight into naive CD4+ T cell homeostasis during aging that can be used to better understand the mechanisms that may contribute to immunosenescence within this compartment.
The host genetic basis of differential outcomes in HIV infection, progression, viral load set point and highly active retroviral therapy (HAART) responses was examined for the common Y haplogroups in European Americans and African Americans. Accelerated progression to acquired immune deficiency syndrome (AIDS) and related death in European Americans among Y chromosome haplogroup I (Y-I) subjects was discovered. Additionally, Y-I haplogroup subjects on HAART took a longer time to HIV-1 viral suppression and were more likely to fail HAART. Both the accelerated progression and longer time to viral suppression results observed in haplogroup Y-I were significant after false-discovery-rate corrections. A higher frequency of AIDS-defining illnesses was also observed in haplogroup Y-I. These effects were independent of the previously identified autosomal AIDS restriction genes. When the Y-I haplogroup subjects were further subdivided into six I subhaplogroups, no one subhaplogroup accounted for the effects on HIV progression, viral load or HAART response. Adjustment of the analyses for population stratification found significant and concordant haplogroup Y-I results. The Y chromosome haplogroup analyses of HIV infection and progression in African Americans were not significant. Our results suggest that one or more loci on the Y chromosome found on haplogroup Y-I have an effect on AIDS progression and treatment responses in European Americans.
Chronic hepatitis B (CH-B) is common among HIV-infected individuals and increases liver-related mortality in the absence of highly active antiretroviral therapy (HAART). The impact of CH-B on long-term HAART outcomes has not been fully characterized.
To address this question, HAART initiators enrolled in the Multicenter AIDS Cohort Study (MACS) were retrospectively analyzed. Subjects were classified by hepatitis B category based on serology at the time of HAART initiation. The association of CH-B with mortality, AIDS defining illnesses, CD4 rise, and HIV suppression was assessed using regression analysis.
Of 816 men followed for a median of 7 years on HAART, 350 were never HBV infected, 357 had past infection, 45 had CH-B, and 64 were only core-antibody positive. Despite HAART, AIDS-related mortality was the most common cause of death (8.3/1000 person-years (PYs)). It was highest in those with CH-B (17/1000 PYs, 95% CI 7.3, 42) and lowest among never HBV infected (2.9/1000 PYs, 95% CI 1.4, 6.4). In a multivariable model, patients with CH-B had a 2.7-fold higher incidence of AIDS-related mortality compared to those never infected (P=0.08). Non-AIDS-related mortality was also highest among those with CH-B (22/1000 PYs), primarily due to liver disease (compared to never infected, adjusted HR 4.1, p=0.04). There was no significant difference in AIDS defining events, HIV RNA suppression, and CD4 increase.
In HIV-infected patients receiving long-term HAART, HBV status did not influence HIV suppression or CD4 increase. However, mortality was highest among those with CH-B and was mostly due to liver disease despite HBV-active HAART.
hepatitis B; HIV; HAART; CD4; mortality; isolated core hepatitis B