Novel association of five HLA alleles with HIV-1 progression in Spanish long-term non progressor patients

Pleiotropic Bias and Study Design Considerations in Genetic Association Studies

Background

Case-control studies are efficient designs for investigating gene-disease associations. A discovery of genome-wide association studies (GWAS) is that many genetic variants are associated with multiple health outcomes and diseases, a phenomenon known as pleiotropy. We aimed to discuss about pleiotropic bias in genetic association studies.

Methods

The opinions of the researchers on the basis of the literature were presented as a critical review.

Results

Pleiotropic effect can bias the results of gene-disease association studies if they use individuals with pre-existing diseases as the control group, while the disease in cases and controls have shared genetic markers. The idea supports the conclusion that when the exposure of interest in a case-control study is a genetic marker, the use of controls from diseased cases that share similar genetic markers may increase the risk of pleiotropic effect. However, not manifesting the disease symptoms among controls at the time of recruitment does not guarantee that the individual will not develop the disease of interest in the future. Age-matched disease-free controls may be a better solution in similar situations. Different analytical techniques are also available that can be used to identify pleiotropic effects. Known pleiotropic effects can be searched from various online databases.

Conclusion

Pleiotropic effects may result in bias in genetic association studies. Suggestions consist of selecting healthy yet age-matched controls and considering diseases with independent genetic architecture. Checking the related databases is recommended before designing a study.

Definition of a New HLA B*52-Restricted Rev CTL Epitope Targeted by an HIV-1-Infected Controller

The analysis of T-cell responses in HIV-1-infected controllers may contribute to a better understanding of the protective components of the immune system. Here, we analyzed the HIV-1-specific T-cell response in a 59-year-old HIV-1-infected controller, infected for at least seven years, who presented with low viral loads ranging from <20 copies/mL to 200 copies/mL and normal CD4 counts of >800 cells/µL. In γ-IFN-ELISpot assays using freshly isolated PBMCs, he displayed a very strong polyclonal T-cell response to eight epitopes in Gag, Nef and Rev; with the dominant responses directed against the HLA-B*57-epitope AISPRTLNAW and against a so-far-unknown epitope within Rev. Further analyses using peptide-stimulated T-cell lines in γ-IFN-ELISpot assays delineated the peptide RQRQIRSI (Rev-RI8) as a newly defined HLA-B*52-restricted epitope located within a functionally important region of Rev. Peptide-stimulation assays in 15 HLA-B*52-positive HIV-1-infected subjects, including the controller, demonstrated recognition of the Rev-RI8 epitope in 6/15 subjects. CD4 counts before the start of antiviral therapy were significantly higher in subjects with recognition of the Rev-RI8 epitope. Targeting of the Rev-RI8 epitope in Rev by CTL could contribute to the positive association of HLA-B*52 with a more favorable course of HIV-1-infection.

Immunological and virological findings in a patient with exceptional post-treatment control: a case report

BACKGROUND

Although antiretroviral therapy (ART) is effective in suppressing viral replication, HIV-1 persists in reservoirs and rebounds after ART has been stopped. However, a very few people (eg, elite and post-treatment controllers) are able to maintain viral loads below detection limits without ART, constituting a realistic model for long-term HIV remission. Here, we describe the HIV control mechanisms of an individual who showed exceptional post-treatment control for longer than 15 years.

METHODS

We report the case of a Hispanic woman aged 59 years with sexually acquired acute HIV infection, who was included in an immune-mediated primary HIV infection trial involving a short course of ciclosporine A, interleukin-2, granulocyte macrophage colony-stimulating factor, and pegylated interferon alfa, followed by analytical treatment interruption. We did the following viral assays: total and integrated HIV-1 DNA in CD4 T cells and rectal tissue, quantitative viral outgrowth assay, HIV-1 infectivity in peripheral blood mononuclear cells and CD4 T-cell cultures and viral inhibitory activity by natural killer (NK) and CD8 T cells. NK and T-cell phenotypes were determined by flow cytometry. HLA, killer cell immunoglobulin-like receptors, Δ32CCR5, and NKG2C alleles were genotyped.

FINDINGS

After ART and immunomodulatory treatment, the person maintained undetectable plasma viral load for 15 years. HIV-1 subtype was CFR_02AG, CCR5-tropic. We found progressive reductions in viral reservoir during the 15-year treatment interruption: total HIV DNA (from 4573·50 copies per 10⁶ CD4 T cells to 95·33 copies per 10⁶ CD4 T cells) and integrated DNA (from 85·37 copies per 10⁶ CD4 T cells to 5·25 copies per 10⁶ CD4 T cells). Viral inhibition assays showed strong inhibition of in vitro HIV replication in co-cultures of CD4 T cells with autologous NK or CD8 T cells at 1:2 ratio (75% and 62%, respectively). Co-cultures with NK and CD8 T cells resulted in 93% inhibition. We detected higher-than-reference levels of both NKG2C-memory-like NK cells (46·2%) and NKG2C γδ T cells (64·9%) associated with HIV-1 control.

INTERPRETATION

We described long-term remission in a woman aged 59 years who was treated during primary HIV infection and has maintained undetectable viral load for 15 years without ART. Replication-competent HIV-1 was isolated. NKG2C-memory-like NK cells and γδ T cells were associated with the control viral replication. Strategies promoting these cells could bring about long-term HIV remission.

FUNDING

Fondo Europeo para el Desarrollo Regional (FEDER), SPANISH AIDS Research Network (RIS), Fondo de Investigación Sanitaria (FIS), HIVACAT, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), CERCA Programme/Generalitat de Catalunya, la Caixa Foundation, and Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC).

TRANSLATION

For the Spanish translation of the abstract see Supplementary Materials section.

Genome-wide association study of hyperthyroidism based on electronic medical record from Taiwan

Excess thyroid hormones have complex metabolic effects, particularly hyperthyroidism, and are associated with various cardiovascular risk factors. Previous candidate gene studies have indicated that genetic variants may contribute to this variable response. Electronic medical record (EMR) biobanks containing clinical and genomic data on large numbers of individuals have great potential to inform the disease comorbidity development. In this study, we combined electronic medical record (EMR) -derived phenotypes and genotype information to conduct a genome-wide analysis of hyperthyroidism in a 35,009-patient cohort in Taiwan. Diagnostic codes were used to identify 2,767 patients with hyperthyroidism. Our genome-wide association study (GWAS) identified 44 novel genomic risk markers in 10 loci on chromosomes 2, 6, and 14 (P < 5 × 10–14), including CTLA4, HCP5, HLA-B, POU5F1, CCHCR1, HLA-DRA, HLA-DRB9, TSHR, RPL17P3, and CEP128. We further conducted a comorbidity analysis of our results, and the data revealed a strong correlation between hyperthyroidism patients with thyroid storm and stroke. In this study, we demonstrated application of the PheWAS using large EMR biobanks to inform the comorbidity development in hyperthyroidism patients. Our data suggest significant common genetic risk factors in patients with hyperthyroidism. Additionally, our results show that sex, body mass index (BMI), and thyroid storm are associated with an increased risk of stroke in subjects with hyperthyroidism.

Omic Technologies in HIV: Searching Transcriptional Signatures Involved in Long-Term Non-Progressor and HIV Controller Phenotypes

This article reviews the main discoveries achieved by transcriptomic approaches on HIV controller (HIC) and long-term non-progressor (LTNP) individuals, who are able to suppress HIV replication and maintain high CD4+ T cell levels, respectively, in the absence of antiretroviral therapy. Different studies using high throughput techniques have elucidated multifactorial causes implied in natural control of HIV infection. Genes related to IFN response, calcium metabolism, ribosome biogenesis, among others, are commonly differentially expressed in LTNP/HIC individuals. Additionally, pathways related with activation, survival, proliferation, apoptosis and inflammation, can be deregulated in these individuals. Likewise, recent transcriptomic studies include high-throughput sequencing in specific immune cell subpopulations, finding additional gene expression patterns associated to viral control and/or non-progression in immune cell subsets. Herein, we provide an overview of the main differentially expressed genes and biological routes commonly observed on immune cells involved in HIV infection from HIC and LTNP individuals, analyzing also different technical aspects that could affect the data analysis and the future perspectives and gaps to be addressed in this field.

Mechanism of Viral Suppression among HIV Elite Controllers and Long-Term Nonprogressors in Nigeria and South Africa

A subgroup among people living with HIV (PLHIV) experience viral suppression, sometimes to an undetectable level in the blood and/or are able to maintain a healthy CD4+ T-cell count without the influence of antiretroviral (ARV) therapy. One out of three hundred PLHIV fall into this category, and a large sample of this group can be found in areas with a high prevalence of HIV infection such as Nigeria and South Africa. Understanding the mechanism underpinning the nonprogressive phenotype in this subgroup may provide insights into the control of the global HIV epidemic. This work provides mechanisms of the elite control and nonprogressive phenotype among PLHIV in Nigeria and South Africa and identifies research gaps that will contribute to a better understanding on HIV controllers among PLHIV.

Association between low levels of HIV-1 DNA and HLA class I molecules in chronic HIV-1 infection

Background

HLA-B27 and -B57 were found in people with low levels of HIV-1 DNA, suggesting that HLA class I molecules may influence the size of HIV-1 reservoir. Aim of the study was to explore the association between HLA class I molecules and HIV-1 DNA in people with chronic HIV-1 infection.

Methods

Post-hoc analysis of the APACHE trial, on adults with chronic HIV-1 infection, prolonged suppressive antiretroviral therapy and good immunological profile. HIV-1 DNA was quantified in peripheral blood mononuclear cells (PBMCs); HLA-A, -B and -C were tested on genomic DNA. Crude odds ratios (OR) with their respective 95% Wald confidence intervals (95% CIs) were estimated by univariable logistic regression for HLAs with a p-value <0.10.

Results

We found 78 and 18 patients with HIV-1 DNA ≥100 copies/10⁶PBMCs and with HIV-1 DNA <100 copies/10⁶PBMCs, respectively. HLA-A24 was present in 21 (29.6%) participants among subjects with HIV-1 DNA ≥100 copies/10⁶PBMCs and 1 (5.9%) among those with HIV-1 DNA <100 copies/10⁶PBMCs (OR = 5.67, 95%CI = 0.79–46.03; p = 0.105); HLA-B39 was present in 1 (1.4%) with HIV-1 DNA ≥100 copies/10⁶PBMCs and in 3 (17.6%) with HIV-1 DNA <100 copies/10⁶PBMCs (OR = 13.71, 95%CI = 1.33–141.77; p = 0.028) and HLA-B55 in 3 (4.2%) and 3 (17.6%), respectively (OR = 4.43, 95%CI = 0.81–24.29; p = 0.087). All the three patients with HLA-B39 and HIV-1 DNA <100 copies/10⁶PBMCs did not have HLA-A24.

Conclusions

In patients with HIV-1 infection who maintained a good virological and immunological profile, HLA-B39 and -B55 may be associated with lower levels of HIV-1 DNA.

Genome-wide association study reveals genetic variants associated with HIV-1C infection in a Botswana study population

Although there have been many studies of gene variant association with different stages of HIV/AIDS progression in United States and European cohorts, few gene-association studies have assessed genic determinants in sub-Saharan African populations, which have the highest density of HIV infections worldwide. We carried out genome-wide association studies on 766 study participants at risk for HIV-1 subtype C (HIV-1C) infection in Botswana. Three gene associations (AP3B1, PTPRA, and NEO1) were shown to have significant association with HIV-1C acquisition. Each gene association was replicated within Botswana or in the United States-African American or United States-European American AIDS cohorts or in both. Each associated gene has a prior reported influence on HIV/AIDS pathogenesis. Thirteen previously discovered AIDS restriction genes were further replicated in the Botswana cohorts, extending our confidence in these prior AIDS restriction gene reports. This work presents an early step toward the identification of genetic variants associated with and affecting HIV acquisition or AIDS progression in the understudied HIV-1C afflicted Botswana population.

HLA class-I-peptide stability mediates CD8+ T cell immunodominance hierarchies and facilitates HLA-associated immune control of HIV

Defining factors that govern CD8+ T cell immunodominance is critical for the rational design of vaccines for viral pathogens. Here, we assess the contribution of human leukocyte antigen (HLA) class-I-peptide stability for 186 optimal HIV epitopes across 18 HLA alleles using transporter associated with antigen processing (TAP)-deficient mono-allelic HLA-expressing cell lines. We find that immunodominant HIV epitopes increase surface stabilization of HLA class-I molecules in comparison to subdominant epitopes. HLA class-I-peptide stability is also strongly correlated with overall immunodominance hierarchies, particularly for epitopes from high-abundance proteins (e.g., Gag). Moreover, HLA alleles associated with HIV protection are preferentially stabilized by epitopes derived from topologically important viral regions at a greater frequency than neutral and risk alleles. These findings indicate that relative stabilization of HLA class-I is a key factor for CD8+ T cell epitope immunodominance hierarchies, with implications for HIV control and the design of T-cell-based vaccines.

Treatment Considerations in an HIV Elite Controller

HIV elite controllers naturally suppress viral loads below limits of detection and evidence lack of evolution of infection for prolonged periods. The role of antiretroviral therapy (ART) in these individuals is controversial. Though recent data suggest that ART may decrease immune activation and prevent complications such as development of accelerated cardiovascular disease (CVD); treatment has not clearly demonstrated a benefit on clinical outcomes (e.g., HIV disease progression, CVD events, mortality). We describe a 49-year-old female HIV elite controller who presented with asymptomatic HIV infection for 26 years and review recent literature on the role of ART in this population.