An additive effect of protective host genetic factors correlates with HIV nonprogression status

Employing computational tools to design a multi-epitope vaccine targeting human immunodeficiency virus-1 (HIV-1)

BACKGROUND

Despite being in the 21^st century, the world has still not been able to vanquish the global AIDS epidemic, and the only foreseeable solution seems to be a safe and effective vaccine. Unfortunately, vaccine trials so far have returned unfruitful results, possibly due to their inability to induce effective cellular, humoral and innate immune responses. The current study aims to tackle these limitations and propose the desired vaccine utilizing immunoinformatic approaches that have returned promising results in designing vaccines against various rapidly mutating organisms. For this, all polyprotein and protein sequences of HIV-1 were retrieved from the LANL (Los Alamos National Laboratory) database. The consensus sequence was generated after alignment and used to predict epitopes. Conserved, antigenic, non-allergenic, T-cell inducing, B-cell inducing, IFN-ɣ inducing, non-human homologous epitopes were selected and combined to propose two vaccine constructs i.e., HIV-1a (without adjuvant) and HIV-1b (with adjuvant).

RESULTS

HIV-1a and HIV-1b were subjected to antigenicity, allergenicity, structural quality analysis, immune simulations, and MD (molecular dynamics) simulations. Both proposed multi-epitope vaccines were found to be antigenic, non-allergenic, stable, and induce cellular, humoral, and innate immune responses. TLR-3 docking and in-silico cloning of both constructs were also performed.

CONCLUSION

Our results indicate HIV-1b to be more promising than HIV-1a; experimental validations can confirm the efficacy and safety of both constructs and in-vivo efficacy in animal models.

The Role of Innate Immunity in Natural Elite Controllers of HIV-1 Infection

The natural process of human immunodeficiency virus type 1(HIV-1) infection is characterized by high viral load, immune cell exhaustion, and immunodeficiency, which eventually leads to the stage of acquired immunodeficiency syndrome (AIDS) and opportunistic infections. Rapidly progressing HIV-1 individuals often die of AIDS several years after infection without treatment. The promotion of ART greatly prolongs the survival time of HIV-infected persons. However, some patients have incomplete immune function reconstruction after ART due to latent storage of HIV-infected cells. Therefore, how to achieve a functional cure has always been the focus and hot spot of global AIDS research. Fortunately, the emergence of ECs/LTNPs who can control virus replication naturally has ignited new hope for realizing a functional cure for AIDS. Recently, a special category of infected individuals has attracted attention that can delay the progression of the disease more rigorously than the natural progression of HIV-1 infection described above. These patients are characterized by years of HIV-1 infection, long-term asymptomatic status, and normal CD4+T cell count without ART, classified as HIV-infected long-term nonprogressors (LTNPs) and elite controllers (ECs). Numerous studies have shown that the host and virus jointly determine the progression of HIV-1 infection, in which the level of innate immunity activation plays an important role. As the first line of defense against pathogen invasion, innate immunity is also a bridge to induce adaptive immunity. Compared with natural progressors, innate immunity plays an antiviral role in HIV-1 infection by inducing or activating many innate immune-related factors in the natural ECs. Learning the regulation of ECs immunity, especially the innate immunity in different characteristics, and thus studying the mechanism of the control of disease progression naturally, will contribute to the realization of the functional cure of AIDS. Therefore, this review will explore the relationship between innate immunity and disease progression in ECs of HIV-1 infection from the aspects of innate immune cells, signaling pathways, cytokines, which is helpful to provide new targets and theoretical references for the functional cure, prevention and control of AIDS, and development of a vaccine.

Influence of HLA-B*5701 on 20 year survival rate among patients living with HIV

BACKGROUND

The life expectancy of people living with HIV (PLWH) remains shorter than that of the general population, despite significant improvement in the recent years. Mortality in HIV-infected individuals may be associated with a higher viral load at of diagnosis, a lower CD4 count, or clinical variables such as sex or route of transmission. This article investigated the role of the HLA-B*5701 varian on mortality among PLWH.

METHODS

Material for the analysis consist of the data of 2,393 patients for whom the HLA-B*57 variant was known. Those patients were followed under the care of the Infectious Diseases Hospital in Warsaw (n = 1555) and the Clinic of Acquired Immunodeficiency of the Pomeranian Medical University in Szczecin (n = 838). Factors such as age, gender, date of HIV diagnosis, route of transmission, date of death, baseline HIV viral load and baseline CD4 counts, were collected, and end-point cross-sectional analyses were marked at 60, 120, 180 and 240 month of observation.

RESULTS

HLA-B*5701 allele was found in 133 (5.5%) analyzed cases. Median age was notably higher for HLA-B*5701 positive patients [32.7 (28.3-41.3) vs. 31.6 (26.8-38.3)years p = 0.02]. HLA-B*5701 was associated with lower baseline viral load [4.21 (3.5-4.8) vs. 4.79 (4.2-5.3)log copies/ml p<0.001] and higher CD4count [448 (294.5-662) vs. 352 (176-514) cells/μl p<0.001]. There were no association between HLA-B*5701 and survival for any given end-point. Higher mortality was associated to male gender, intravenous drug users, lower CD4 count at baseline and higher baseline viral load.

CONCLUSIONS

In our study, the presence of HLA-B*5701 allel was not associated with mortality rate of HIV infected patients, irrespective of being associated with both higher baseline CD4 + cell count and lower baseline HIV viral load.

Mauritian cynomolgus macaques with M3M4 MHC genotype control SIVmac251 infection

BACKGROUND

Understanding natural HIV control may lead to new preventative or therapeutic strategies. Several protective major histocompatibility complex (MHC) genotypes were found in humans and rhesus macaques. Here, we report a simian immunodeficiency virus (SIV) controller MHC genotype in Mauritian cynomolgus macaques (MCMs).

METHODS

Twelve MHC-genotyped MCMs were infected with SIVmac251 and monitored for viral loads and CD4+ T-cell counts.

RESULTS

Two macaques with M3M4 genotype exhibited the lowest peak viral loads (log plasma SIV RNA copies/mL), nearly 3 logs lower than those in most macaques with other MHC haplotype combinations, and set point viral loads below the level of detection limit by RT-qPCR (<2 log RNA copies/mL). They maintained healthy CD4+ T-cell counts of >500 cells/μL blood, while CD4 counts in the vast majority of other macaques were below this level.

CONCLUSIONS

The M3M4 MHC genotype may confer enhanced control of SIV replication in MCMs.

What Is the most Important for Elite Control: Genetic Background of Patient, Genetic Background of Partner, both or neither? Description of Complete Natural History within a Couple of MSM

Background

We describe a homosexual man who strongly controlled HIV-1 for ten years despite lack of protective genetic background.

Methods

HIV-1 DNA was measured in blood and other tissues. Cell susceptibility was evaluated with various strains. HIV-1-specific (CD4 and CD8 activation markers and immune check points) and NK cells responses were assessed; KIRs haplotypes and HLA alleles were determined.

Findings

Two HIV-1 RNA copies/mL of plasma were detected in 2009, using an ultra-sensitive assay. HIV-DNA was detected at 1.1 and 2 copies/10⁶ PBMCs in 2009 and 2015 respectively, at 1.2 copies/10⁶ cells in rectal cells in 2011. WBs showed weak reactivity with antibodies to gp160, p55 and p25 from 2007 to 2014, remaining incomplete in 2017. CD4 T cells were susceptible to various strains including HIV_KON, a primary isolate of his own CRF02_AG variant. CD8 T cells showed a strong poly-functional response against HIV-Gag, producing mainly IFN-γ; a robust capacity of antibody-dependant cell cytotoxicity (ADCC) was observed in NK cells. Case patient was group B KIR haplotype. Neutralizing antibodies were not detected. CD4 and CD8 blood T cells showed normal proportions without increased activation markers. Phylogenetic analyses identified the same CRF02_AG variant in his partner. The patient and his partner were heterozygous for the CCR5ΔD32 deletion and shared HLA-B*07, C*07 non-protective alleles.

Interpretation

This thorough description of the natural history of an individual controlling HIV-1 in various compartments for ten years despite lack of protective alleles, and of his partner, may have implications for strategies to cure HIV-1 infection.

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We described a MSM, elite controller despite pejorative genetic background.

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The patient had two HLA pejoratives alleles and no protective alleles.

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The partner was infected by the same strain.

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The genetic backgrounds of the patient and partner, and the virus could interact with each other to lead to elite control.

We considered all the evidence about elite control, HLA, ADCC and NK, using Medline/PubMed. We described a MSM, elite controller despite non-protective genetic background, explored extensively the patient: sequential WBs, RNA in plasma (ultrasensitive assay), DNA in PBMC/GALT, cell susceptibility, HIV-1 responses in PBMC/LNMC, neutralizing antibodies, CD3-CD56 + NK, ADCC, KIRs. He had one HLA pejorative and no protective alleles. The partner was infected by the same strain, his genetic background was studied. The genetic background of the exposed person, of the source, and the viral strain could interact with each other to lead to elite control.

Enrichment of HLA Types and Single-Nucleotide Polymorphism Associated With Non-progression in a Strictly Defined Cohort of HIV-1 Controllers

HIV-1 controllers (HIC) are extremely rare patients with the ability to control viral replication, maintain unchanging CD4 T-cell count, and evade disease progression for extensive periods of time, in the absence of antiretroviral therapy. In order to establish the representation of key genetic correlates of atypical disease progression within a cohort of HIV-1⁺ individuals who control viral replication, we examine four-digit resolution HLA type and single-nucleotide polymorphisms (SNP) previously identified to be correlated to non-progressive infection, in strictly defined HIC. Clinical histories were examined to identify patients exhibiting HIC status. Genomic DNA was extracted, and high definition HLA typing and genome-wide SNP analysis was performed. Data were compared with frequencies of SNP in European long-term non-progressors (LTNP) and primary infection cohorts. HLA-B alleles associated with atypical disease progression were at very high frequencies in the group of five HIC studied. All four HIC of European ancestry were HLA-B*57⁺ and half were also HLA-B*27⁺. All HIC, including one of self-reported African ethnicity, had the HLA-Cw*0602 allele, and the HLA-DQ9 allele was present only in HIC of European ancestry. A median 95% of the top 19 SNP known to be associated with LTNP status was observed in European HIC (range 78–100%); 17/19 of the SNP considered mapped to chromosome 6 in the HLA region, whereas 2/19 mapped to chromosome 8. The HIC investigated here demonstrated high enrichment of HLA types and SNP previously associated with long-term non-progression. These findings suggest that the extreme non-progressive phenotype considered here is associated with a genetic signature characterized by a single-genetic unit centered around the HLA-B*57 haplotype and the possible additive effect of HLA-B*27.

Enhanced Recognition of HIV-1 Cryptic Epitopes Restricted by HLA Class I Alleles Associated With a Favorable Clinical Outcome

BACKGROUND

Cryptic epitopes (CEs) are peptides derived from the translation of 1 or more of the 5 alternative reading frames (ARFs; 2 sense and 3 antisense) of genes. Here, we compared response rates to HIV-1-specific CE predicted to be restricted by HLA-I alleles associated with protection against disease progression to those without any such association.

METHODS

Peptides (9mer to 11mer) were designed based on HLA-I-binding algorithms for B*27, B*57, or B*5801 (protective alleles) and HLA-B*5301 or B*5501 (nonprotective allele) in all 5 ARFs of the 9 HIV-1 encoded proteins. Peptides with >50% probability of being an epitope (n = 231) were tested for T-cell responses in an IFN-γ enzyme-linked immunosorbent spot (ELISpot) assay. Peripheral blood mononuclear cell samples from HIV-1 seronegative donors (n = 42) and HIV-1 seropositive patients with chronic clade B infections (n = 129) were used.

RESULTS

Overall, 16%, 2%, and 2% of chronic HIV infected patients had CE responses by IFN-γ ELISpot in the protective, nonprotective, and seronegative groups, respectively (P = 0.009, Fischer exact test). Twenty novel CE-specific responses were mapped (median magnitude of 95 spot forming cells/10 peripheral blood mononuclear cells), and most were both antisense derived (90%) and represented ARFs of accessory proteins (55%). CE-specific CD8 T cells were multifunctional and proliferated when assessed by intracellular cytokine staining.

CONCLUSIONS

CE responses were preferentially restricted by the protective HLA-I alleles in HIV-1 infection, suggesting that they may contribute to viral control in this group of patients.

[Prevalence study of the genetic markers associated with slow progression of human inmunodefiency virus type 1 in the Galician population (Northwest of Spain)]

INTRODUCTION

The deletion in the CCR5 gene (CCR5Δ32), the HLA-B*27:05, and polymorphisms rs2395029 and rs9264942 have been associated with slower progression of HIV-1.

METHODS

An analysis was performed on 408 patients on follow-up. The analysis of viral load, CD4+ Tlymphocytes and other clinical variables since the diagnosis of the infection were collected.

RESULTS

The prevalence of the genetic markers rs9264942, CCR5wt/Δ32, rs2395029, HLA-B*27:05 was 17.9%, 11.5%, 7.6%, and 6.4%, respectively. Of all the patients, 354 were classified as progressors and 46 as long-term non-progressors (LTNPs). Except for the HLA-B*27:05 allele, other genetic markers were associated with slower progression: CCR5wt/Δ32 (P=.011) and SNPs rs2395029 and rs9264942 (P<.0001), as well as their association (P<.0001).

CONCLUSION

The prevalence of the HLA-B*57:01 allele was higher than described nationally. No association could be found between the HLA-B*27:05 allele and the presence of slower disease progression.

HIV-infected sex workers with beneficial HLA-variants are potential hubs for selection of HIV-1 recombinants that may affect disease progression

Cytotoxic T lymphocyte (CTL) responses against the HIV Gag protein are associated with lowering viremia; however, immune control is undermined by viral escape mutations. The rapid viral mutation rate is a key factor, but recombination may also contribute. We hypothesized that CTL responses drive the outgrowth of unique intra-patient HIV-recombinants (URFs) and examined gag sequences from a Kenyan sex worker cohort. We determined whether patients with HLA variants associated with effective CTL responses (beneficial HLA variants) were more likely to carry URFs and, if so, examined whether they progressed more rapidly than patients with beneficial HLA-variants who did not carry URFs. Women with beneficial HLA-variants (12/52) were more likely to carry URFs than those without beneficial HLA variants (3/61) (p < 0.0055; odds ratio = 5.7). Beneficial HLA variants were primarily found in slow/standard progressors in the URF group, whereas they predominated in long-term non-progressors/survivors in the remaining cohort (p = 0.0377). The URFs may sometimes spread and become circulating recombinant forms (CRFs) of HIV and local CRF fragments were over-represented in the URF sequences (p < 0.0001). Collectively, our results suggest that CTL-responses associated with beneficial HLA variants likely drive the outgrowth of URFs that might reduce the positive effect of these CTL responses on disease progression.

Vitamin-D pathway genes and HIV-1 disease progression in injection drug users

Vitamin-D has pleiotropic effects on calcium and bone metabolism, cellular growth control, cell differentiation and modulation of both innate and acquired immune response. Previous studies revealed the association of vitamin-D receptor gene (VDR) polymorphism with infection diseases including HIV-1 infection. To assess for association between polymorphisms of vitamin-D pathway genes CYP27B1, vitamin-D binding protein (VDBP) and VDR with HIV-1 infection, disease progression to acquired immunodeficiency syndrome (AIDS) was analysed according to CDC93 criteria in a cohort of 185 HIV-1 seroprevalent patients belonging to the injection drug users. Genotype data was obtained from rs10877012, rs3782130 and rs4646536 markers at CYP27B1 locus; rs7041 and rs4588 at VDBP locus; and rs11568820, rs4516035, rs2228570, rs1544410 and rs17878969 at VDR locus. Distribution of genotypes between patients grouped by outcome was compared by contingency table analysis. Marker-marker interaction was assessed by a MDR analysis. Assuming an additive model for VDR markers, a Kaplan-Meier survival analysis was employed to evaluate association with disease progression. Among vitamin-D pathway genes, VDR locus reveals specific 5'UTR and 3'UTR diplotype combinations associated with both, slower and faster progression to AIDS. Marker-marker interaction analysis indicates a strong interaction between VDR markers and a redundant effect for CYP27B1 markers. According to our results, VDR locus association follows an additive model in which increased genetic risk score for the VDR is directly correlated with AIDS progression rates. Our data supports a role of vitamin-D pathway gene variability on HIV-1 disease progression.

HLA B*5701 status, disease progression, and response to antiretroviral therapy

OBJECTIVE

In addition to hypersensitivity reactions to abacavir, HLA B5701 has been associated with slow or nonprogression of HIV infection. We explored the effect of HLA B5701 on CD4 cell count and viral load in untreated patients and on responses to nonabacavir-containing combination antiretroviral therapy (cART) in a large UK-based cohort.

DESIGN

Analysis of a cohort of HIV-infected adults.

METHODS

In untreated patients, CD4 cell count and viral load at study entry were compared in HLAB5701-positive and HLAB5701-negative individuals and linear regression tested for an interaction effect of viral load and HLA B5701 on CD4 cell count. In patients starting a nonabacavir cART regimen, Cox proportional hazards models compared virological responses to cART among HLA B5701-negative, HLA B5701-positive, and those not tested. Six-month and 12-month changes in CD4 cell count were used as outcomes in linear regression to compare immunological response to cART in these groups.

RESULTS

ART-naive HLA B5701-positive individuals had higher CD4 cell count (P<0.0001) and lower viral load (P<0.0001) at study entry than negatives; however, HLA B5701 status was not found to effect the association between viral load and CD4 cell count (interaction P value=0.09). HLA B5701-positive patients were more likely to achieve viral suppression than negative patients on a nonabacavir regimen [hazard ratio=1.29, 95% confidence interval, CI (1.15-1.54)] and less likely to experience viral rebound [hazard ratio=0.61, 95% CI (0.37-0.99)].

CONCLUSION

Better virological but not immunological responses to cART were seen in HLA B5701-positive patients on nonabacavir regimens. This study provides further evidence of the potentially beneficial effect of HLA B5701 on HIV progression.

Implications of the incidentalome for clinical pharmacogenomics

Incidental findings have long posed challenges for healthcare providers, but the scope and scale of these challenges have increased with the introduction of new technologies. This article assesses the impact of incidental findings on the introduction of prospective pharmacogenomic testing into clinical use. Focusing on the challenges of the incidentalome, the large set of incidental findings potentially generated through genotyping, the paper argues that provisional approaches to managing incidental findings may be implemented if necessary to allow benefits of pharmacogenomic testing to be realized in the clinical setting. In the longer term, approaches to returning incidental findings may need to focus on limiting the number of incidental findings to a number that can be addressed by patients and providers.

Cell-Mediated Immunity in Elite Controllers Naturally Controlling HIV Viral Load

The natural course of human immunodeficiency virus (HIV) infection is characterized by high viral load, depletion of immune cells, and immunodeficiency, ultimately leading to acquired immunodeficiency syndrome phase and the occurrence of opportunistic infections and diseases. Since the discovery of HIV in the early 1980s a naturally selected population of infected individuals has been emerged in the last years, characterized by being infected for many years, with viremia constantly below detectable level and poor depletion of immune cells. These individuals are classified as “elite controllers (EC) or suppressors” and do not develop disease in the absence of anti-retroviral therapy. Unveiling host factors and immune responses responsible for the elite status will likely provide clues for the design of therapeutic vaccines and functional cures. Scope of this review was to examine and discuss differences of the cell-mediated immune responses between HIV+ individuals with disease progression and EC.

HLA class I protective alleles in an HIV-1-infected subject homozygous for CCR5-Δ32/Δ32

Homozygosity for a 32 bp deletion in CCR5 (CCR5-Δ32/Δ32) is associated with strong resistance against HIV-1 infection. Several HLA types have been associated to improved viral control and/or delayed progression to AIDS. We report a unique HIV-1 infected individual homozygous for CCR5-Δ32/Δ32 and carrier of HLA-A*2402 and HLA-B*5701. In comparison with earlier data and although a replication competent virus has been isolated, the patient presents better immune status, response to treatment and disease evolution, which may be related to the control exerted by HLA class I restricted T cell immunity. Importantly, the accumulation of protective factors does not warrant a complete protection to HIV infection and the subsequent life-long treatment.

HLA-C and HIV-1: friends or foes?

The major histocompatibility complex class I protein HLA-C plays a crucial role as a molecule capable of sending inhibitory signals to both natural killer (NK) cells and cytotoxic T lymphocytes (CTL) via binding to killer cell Ig-like receptors (KIR). Recently HLA-C has been recognized as a key molecule in the immune control of HIV-1. Expression of HLA-C is modulated by a microRNA binding site. HLA-C alleles that bear substitutions in the microRNA binding site are more expressed at the cell surface and associated with the control of HIV-1 viral load, suggesting a role of HLA-C in the presentation of antigenic peptides to CTLs. This review highlights the role of HLA-C in association with HIV-1 viral load, but also addresses the contradiction of the association between high cell surface expression of an inhibitory molecule and strong cell-mediated immunity. To explore additional mechanisms of control of HIV-1 replication by HLA-C, we address specific features of the molecule, like its tendency to be expressed as open conformer upon cell activation, which endows it with a unique capacity to associate with other cell surface molecules as well as with HIV-1 proteins.

Differential prevalence of the HLA-C -- 35 CC genotype among viremic long term non-progressor and elite controller HIV+ individuals

Susceptibility to HIV infection and disease progression are complex traits modulated by environmental and genetic factors, affecting innate and adaptive immune responses, among other cellular processes. A single nucleotide polymorphism (SNP) 35 kb upstream of the HLA-C gene locus (-35C/T) was previously shown to correlate with increased HLA-C expression and improved control of HIV-1. Here, we genotyped the -35C/T SNP in 639 subjects (180 uninfected patients, 304 HIV progressors and 155 LTNP) and confirmed the association of the -35C/T variant with the LTNP phenotype. The genotype frequencies in the general population subjects did not differ significantly from those seen in HIV progressors (p-value=0.472). However, a significant higher frequency of the protective CC genotype was identified when LTNP were compared either with HIV progressors alone (p-value<0.0001) or progressors and uninfected subjects together (p-value<0.0001). When considering aviremic LTNP alone (elite controllers; viral load below 50 copies/ml), the -35 CC genotype was not overrepresented compared to HIV progressors. Conversely, a significant association was found with the viremic LTNP groups (viral loads below 10,000 copies/ml). These results suggest that other factors alone or in combination with the -35 CC genotype may play an important role in differentiating the elite controller status from LTNP. Combination of different genetic variants may have additive or epistatic effects determining the HIV course of infection.

The role of MHC class I allele Mamu-A*07 during SIV(mac)239 infection

Virus-specific CD8(+) T cells play an important role in controlling HIV/SIV replication. These T cells recognize intracellular pathogen-derived peptides displayed on the cell surface by individual MHC class I molecules. In the SIV-infected rhesus macaque model, five Mamu class I alleles have been thoroughly characterized with regard to peptide binding, and a sixth was shown to be uninvolved. In this study, we describe the peptide binding of Mamu-A1*007:01 (formerly Mamu-A*07), an allele present in roughly 5.08% of Indian-origin rhesus macaques (n = 63 of 1,240). We determined a preliminary binding motif by eluting and sequencing endogenously bound ligands. Subsequently, we used a positional scanning combinatorial library and panels of single amino acid substitution analogs to further characterize peptide binding of this allele and derive a quantitative motif. Using this motif, we selected and tested 200 peptides derived from SIV(mac)239 for their capacity to bind Mamu-A1*007:01; 33 were found to bind with an affinity of 500 nM or better. We then used PBMC from SIV-infected or vaccinated but uninfected, A1*007:01-positive rhesus macaques in IFN-γ Elispot assays to screen the peptides for T-cell reactivity. In all, 11 of the peptides elicited IFN-γ(+) T-cell responses. Six represent novel A1*007:01-restricted epitopes. Furthermore, both Sanger and ultradeep pyrosequencing demonstrated the accumulation of amino acid substitutions within four of these six regions, suggestive of selective pressure on the virus by antigen-specific CD8(+) T cells. Thus, it appears that Mamu-A1*007:01 presents SIV-derived peptides to antigen-specific CD8(+) T cells and is part of the immune response to SIV(mac)239.

HLA alleles are associated with altered risk for disease progression and central nervous system impairment of HIV-infected children

OBJECTIVE

To examine the effects of human leukocyte antigen (HLA) alleles on HIV-1-related disease progression and central nervous system (CNS) impairment in children.

DESIGN

Five hundred seventy-two HIV-1-infected children, identified as disease progressors or nonprogressors, were selected from PACTG P152 and P300 through a case-cohort sampling scheme. Study endpoints were HIV-1-related disease progression-free survival and time to CNS impairment.

METHODS

DNA was genotyped for HLA alleles using a Luminex 100 platform. Weighted Kaplan-Meier methods, and Cox proportional hazards models were used to assess the effects of HLA alleles on study endpoints.

RESULTS

Presence of the B-27 allele (n = 20) was associated with complete protection against disease progression and CNS impairment over the median follow-up of 26 months (P < 0.0001 for both). These findings held in multivariate analyses controlling for baseline covariates including race, gender, age, log HIV-1 RNA, CD4 lymphocyte count and percent, weight for age z score and treatment, and for other genotypes shown to affect HIV-1-related disease progression. Also, although the Cw-2 allele protected against disease progression [Hazard ratio (HR), 0.48; 95% confidence interval (CI): 0.28 to 0.81; P = 0.006], the A-24 allele was associated with more rapid CNS impairment (HR: 2.01; 95% CI: 1.04 to 3.88; P = 0.04). The HLA class II DQB1-2 allele was associated with a delayed disease progression (HR: 0.66; 95% CI: 0.47-0.92; P = 0.01) and CNS impairment (HR: 0.58; 95% CI: 0.36 to 0.93; P = 0.02).

CONCLUSIONS

Presence of B-27, Cw-2, or DQB1-2 alleles was associated with delayed HIV-1 disease progression, while B-27, A-24, and DQB1-2 alleles were associated with altered progression to CNS impairment in children.