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
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 (MACS) whether progressive deterioration of the immune system among HIV positive individuals independently predicts onset of FRP.
FRP was evaluated semiannually in 1,046 HIV-infected men from 1994–2005. CD4 T-cell count and plasma viral load were evaluated as predictors of FRP by logistic regression (GEE), adjusting for age, ethnicity, educational level, AIDS status, and treatment era (pre-HAART (1994–1995) and HAART (1996–1999 and 2000–2005)).
Adjusted prevalences of FRP remained low for CD4 T-cell counts >400 cells/mm3 and increased exponentially and significantly for lower counts. Results were unaffected by treatment era. After 1996, CD4 cell T-count, but not plasma viral load, was independently associated with FRP.
CD4 T-cell count predicted the development of a frailty-related phenotype 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.
HIV; aging; frailty; CD4 T-cell count; Highly active antiretroviral therapy; prospective population-based cohort
Detection of HIV-1 in patients is limited by the sensitivity and selectivity of available tests. The nanotechnology-based bio-barcode-amplification method offers an innovative approach to detect specific HIV-1 antigens from diverse HIV-1 subtypes. We evaluated the efficacy of this protein-detection method in detecting HIV-1 in men enrolled in the Chicago component of the Multicenter AIDS Cohort Study (MACS).
The method relies on magnetic microparticles with antibodies that specifically bind the HIV-1 p24 Gag protein and nanoparticles that are encoded with DNA and antibodies that can sandwich the target protein captured by the microparticle-bound antibodies. The aggregate sandwich structures are magnetically separated from solution, and treated to remove the conjugated barcode DNA. The DNA barcodes (hundreds per target) were identified by a nanoparticle-based detection method that does not rely on PCR.
Of 112 plasma samples from HIV-1-infected subjects, 111 were positive for HIV-1 p24 Gag protein (range: 0.11–71.5 ng/ml of plasma) by the bio-barcode-amplification method. HIV-1 p24 Gag protein was detected in only 23 out of 112 men by the conventional ELISA. A total of 34 uninfected subjects were negative by both tests. Thus, the specificity of the bio-barcode-amplification method was 100% and the sensitivity 99%. The bio-barcode-amplification method detected HIV-1 p24 Gag protein in plasma from all study subjects with less than 200 CD4+ T cells/μl of plasma (100%) and 19 out of 20 (95%) HIV-1-infected men who had less than 50 copies/ml of plasma of HIV-1 RNA. In a separate group of 60 diverse international isolates, representative of clades A, B, C and D and circulating recombinant forms CRF01_AE and CRF02_AG, the bio-barcode-amplification method identified the presence of virus correctly.
The bio-barcode-amplification method was superior to the conventional ELISA assay for the detection of HIV-1 p24 Gag protein in plasma with a breadth of coverage for diverse HIV-1 subtypes. Because the bio-barcode-amplification method does not require enzymatic amplification, this method could be translated into a robust point-of-care test.
bio-barcode-amplification method; HIV-1; major core protein of HIV-1 (p24 Gag)
We examined the emergence of CXCR4 (i.e., X4) tropism in 67 male human immunodeficiency virus type 1 (HIV-1) seroconverters from the Multicenter AIDS Cohort Study (MACS) who were selected to reflect the full spectrum of rates of HIV-1 disease progression. A mean of 10 serial samples per donor were evaluated by a laboratory-validated, commercially available assay to determine phenotypic coreceptor use. A total of 52% of men had dual- or mixed-tropic HIV-1 detected at 1 or more of the time points tested. Use of X4 by HIV-1 was detected more frequently among men who developed AIDS (defined as a CD4+ T cell count of < 200 cells/μL and/or an AIDS-defining illness)≤11 years after seroconversion than among those who did not (P = .005), as well as among men who exhibited a total T cell count decline (i.e., a CD3+ inflection point), compared with those who did not (P = .03). For men in whom both X4 virus and an inflection point were detected, emergence of X4 virus preceded the inflection point by a median of 0.83 years. The median CD4+ T cell count at first detection of X4 viruses before the onset of AIDS was 475 cells/μL. We conclude that HIV-1 variants that used X4 frequently emerged at high CD4+ T cell counts and may contribute to the decrease in T cell numbers during late HIV-1 infection.
As availability of primary cells can be limited for genetic studies of human disease, lymphoblastoid cell lines (LCL) are common sources of genomic DNA. LCL are created in a transformation process that entails in vitro infection of human B-lymphocytes with the Epstein-Barr Virus (EBV).
To test for genotypic errors potentially induced by the Epstein-Barr Virus transformation process, we compared single nucleotide polymorphism (SNP) genotype calls in peripheral blood mononuclear cells (PBMC) and LCL from the same individuals. The average mismatch rate across 19 comparisons was 0.12% for SNPs with a population call rate of at least 95%, and 0.03% at SNPs with a call rate of at least 99%. Mismatch rates were not correlated across genotype subarrays run on all sample pairs.
Genotypic discrepancies found in PBMC and LCL pairs were not significantly different than control pairs, and were not correlated across subarrays. These results suggest that mismatch rates are minimal with stringent quality control, and that most genotypic discrepancies are due to technical artifacts rather than the EBV transformation process. Thus, LCL likely constitute a reliable DNA source for host genotype analysis.
There is notable heterogeneity in the progression to Kaposi’s Sarcoma (KS) among men coinfected with HIV-1 and HHV-8; additional determinants of KS likely exist. Here, we explore sexual activity as a proxy for a sexually transmitted determinant beyond HIV-1 and HHV-8.
The association between sexual activity and incident KS was estimated using data from 1,354 HIV-1 and HHV-8 coinfected homosexual men followed for up to 10 years in the Multicenter AIDS Cohort Study.
As expected, white race, low CD4 cell count and acquiring HHV-8 after HIV-1 infection increased, while smoking decreased, the hazard of KS. The unadjusted hazard of KS among those with high sexual activity was 0.68 relative to the hazard of those with low sexual activity (95% confidence interval [CI]: 0.49, 0.93), and was somewhat muted after adjustment for characteristics measured at study entry (i.e. race, smoking, CD4 cell count, infection order, history of sexual activity, and sexually transmitted diseases). However, adjustment for time-varying covariates, particularly CD4 cell count, resulted in a nullification of the association (adjusted hazard ratio = 1.06; 95% CI: 0.77, 1.48).
Once HIV-1 and HHV-8 coinfection is established in homosexual men, progression to KS does not appear to be due to a third pathogen transmitted by sexual activity.
HIV-1; HHV-8; Kaposi’s sarcoma; sexual activity
Several long-term cohort studies and in-vitro fitness assays have resulted in inconsistent reports on changes in HIV-1 virulence, including reports of decreasing, stable, and increasing virulence over the course of the AIDS pandemic. We tested the hypothesis of changing HIV-1 virulence by examining trends in prognostic clinical markers of disease progression from 1984 to 2005 among nearly 400 antiretroviral-naïve participants in the United States Multicenter AIDS Cohort Study (MACS), a longitudinal study of HIV infection in men who have sex with men (MSM).
Because clinical AIDS endpoints could not be used (due to antiretroviral therapies and prophylaxis), three prognostic markers of disease progression were used as proxies for HIV-1 virulence: plasma viral RNA load and CD4+ T cell count at “set point” (between ∼9 and ∼15 months after seroconversion), and rate of CD4 cell decline within three years after seroconversion. We performed multivariate analyses of the association between these markers and seroconversion year, with covariates including MACS site, race/ethnic group, seroconversion age, and CCR5Δ32 status. No statistically significant association was found between year of seroconversion and “set point” plasma viral load (at ∼9 months after seroconversion: slope = −0.004 log10 copies/mL/year, p = 0.76; at ∼15 months: slope = −0.005 log10 copies/mL/year, p = 0.71), CD4 cell count after seroconversion (at ∼9 months: slope = −0.112 cells/µL/year, p = 0.22; at ∼15 months: slope = −0.047 cells/µL/year, p = 0.64), or rate of CD4 cell decline over the first three years after seroconversion (slope = −0.010 cells/ul/yr2, p = 0.88).
The lack of significant trends from 1984 to 2005 in these prognostic markers of HIV disease progression suggests no major change in HIV-1 virulence over the AIDS pandemic in MSM in the US.
Human apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3 (Apobec3) antiretroviral factors cause hypermutation of proviral DNA leading to degradation or replication-incompetent HIV-1. However, HIV-1 viral infectivity factor (Vif) suppresses Apobec3 activity through the Cullin 5-Elongin B-Elongin C E3 ubiquitin ligase complex. We examined the effect of genetic polymorphisms in the CUL5 gene (encoding Cullin 5 protein) on AIDS disease progression in five HIV-1 longitudinal cohorts. A total of 12 single nucleotide polymorphisms (SNPs) spanning 93 kb in the CUL5 locus were genotyped and their haplotypes inferred. A phylogenetic network analysis revealed that CUL5 haplotypes were grouped into two clusters of evolutionarily related haplotypes. Cox survival analysis and mixed effects models were used to assess time to AIDS outcomes and CD4+ T cell trajectories, respectively. Relative to cluster I haplotypes, the collective cluster II haplotypes were associated with more rapid CD4+ T cell loss (relative hazards [RH] = 1.47 and p = 0.009), in a dose-dependent fashion. This effect was mainly attributable to a single cluster II haplotype (Hap10) (RH = 2.49 and p = 0.00001), possibly due to differential nuclear protein–binding efficiencies of a Hap10-specifying SNP as indicated by a gel shift assay. Consistent effects were observed for CD4+ T cell counts and HIV-1 viral load trajectories over time. The findings of both functional and genetic epidemiologic consequences of CUL5 polymorphism on CD4+ T cell and HIV-1 levels point to a role for Cullin 5 in HIV-1 pathogenesis and suggest interference with the Vif-Cullin 5 pathway as a possible anti-HIV-1 therapeutic strategy.
Human apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3 G (Apobec3G) is an innate antiviral protein that inhibits HIV type 1 (HIV-1) replication by causing deleterious mutations in the HIV-1 genome. Unfortunately, HIV-1 has a strategy to defeat the antiviral activity of Apobec3G. The HIV-1 viral infectivity factor (Vif) binds to Apobec3G leading to the degradation of Apobec3G through a complex containing Cullin 5 and the proteins Elongin B and Elongin C. Since Cullin 5 directly interacts with Vif and is critical to the Apobec3G degradation pathway, the authors asked if genetic variation of CUL5 could tip the balance between HIV-1 and Apobec3G and modify the course of HIV-1 infection. They showed that genetic variation in the CUL5 gene encoding Cullin 5 affected the rate of CD4+ T cell loss in patients infected with HIV-1. CUL5 haplotypes formed two clusters of evolutionarily related haplotypes with opposing effects—cluster I delayed and the cluster II accelerated CD4+ T cell loss. The effect was mainly attributable to a single haplotype or its tagging-SNP, which demonstrated differential binding of transcription factors. This finding highlights the epidemiologic importance of the HIV-1 and Cullin 5 interaction and suggests that the factors in the HIV-1 Vif-Apobec3G degradation pathway may be targets for antiviral drugs.