Polymorphisms in the interleukin-7 receptor α gene and mortality in untreated HIV-infected individuals

IL7RA rs10491434 polymorphism is related to spontaneous HIV infection control in naïve HIV-infected patients: A retrospective study

Interleukin 7 receptor (IL7R) is vital in the adaptive immune response against human immunodeficiency viruses (HIV). We assessed IL7RA polymorphisms (SNPs) in antiretroviral therapy (ART)-naïve HIV patients for their association with spontaneous HIV infection control. We conducted a retrospective cohort study involving 667 ART-naïve patients categorized by HIV progression (ordinal variable): 150 rapid progressors, 334 moderate/typical progressors, 86 long-term nonprogressors elite controllers (LTNPs-EC), and 97 LTNPs-non-EC. We genotyped three IL7RA SNPs using Agena Bioscience's MassARRAY platform. The association between IL7RA SNPs and spontaneous HIV infection control was evaluated using ordinal logistic regression. Individuals carrying the rs10491434 G allele have a higher likelihood of spontaneous HIV infection control (adjusted odds ratio [aOR] = 1.33; p = 0.023). Moreover, the IL7RA GCT haplotype, consisting of three specific SNPs (rs6897932, rs987106, and rs10491434), demonstrated an association with the control of untreated HIV infection (aOR = 1.34; p = 0.050). Remarkably, the rs10491434 SNP and the IL7RA GCT haplotype exhibited similar aOR values, suggesting that rs10491434 may be primarily responsible for the observed effect of the haplotype. IL7RA rs10491434 G allele is associated with a higher likelihood of spontaneous HIV infection control, indicating its significant role in the pathogenesis of HIV, possibly influencing infection course and viral replication control.

IL7RA single nucleotide polymorphisms are associated with the size and function of the MAIT cell population in treated HIV-1 infection

MAIT cells are persistently depleted and functionally exhausted in HIV-1-infected patients despite long-term combination antiretroviral therapy (cART). IL-7 treatment supports MAIT cell reconstitution in vivo HIV-1-infected individuals and rescues their functionality in vitro. Single-nucleotide polymorphisms (SNPs) of the IL-7RA gene modulate the levels of soluble(s)IL-7Rα (sCD127) levels and influence bioavailability of circulating IL-7. Here we evaluate the potential influence of IL-7RA polymorphisms on MAIT cell numbers and function in healthy control (HC) subjects and HIV-1-infected individuals on long-term cART. Our findings indicate that IL-7RA haplotype 2 (H2*T), defined as T-allele carriers at the tagging SNP rs6897932, affects the size of the peripheral blood MAIT cell pool, as well as their production of cytokines and cytolytic effector proteins in response to bacterial stimulation. H2*T carriers had lower sIL-7Rα levels and higher MAIT cell frequency with enhanced functionality linked to higher expression of MAIT cell-associated transcription factors. Despite an average of 7 years on suppressive cART, MAIT cell levels and function in HIV-1-infected individuals were still significantly lower than those of HC. Notably, we observed a significant correlation between MAIT cell levels and cART duration only in HIV-1-infected individuals carrying IL-7RA haplotype 2. Interestingly, treatment with sIL-7Rα in vitro suppressed IL-7-dependent MAIT cell proliferation and function following cognate stimulations. These observations suggest that sIL-7Rα levels may influence MAIT cell numbers and function in vivo by limiting IL-7 bioavailability to MAIT cells. Collectively, these observations suggest that IL-7RA polymorphisms may play a significant role in MAIT cell biology and influence MAIT cells recovery in HIV-1 infection. The potential links between IL7RA polymorphisms, MAIT cell immunobiology, and HIV-1 infection warrant further studies going forward.

The Association of IL7R rs6897932 with Risk of Multiple Sclerosis in Southern Chinese

OBJECTIVE

To investigate the association between IL7R rs6897932 and multiple sclerosis (MS) in southern Chinese people.

METHODS

In total, 147 MS patients and 530 healthy controls were recruited according to the revised McDonald criteria. The TaqMan method was used for genotyping.

RESULTS

With genetic models, we can observe that the additive model, the dominant model, and the recessive model of IL7R rs6897932 were significantly associated with MS [additive model: p=0.032; dominant model (adjusted): p<0.001, OR=3.61 (95% CI 2.25-5.83); recessive model (adjusted): p<0.001, OR=6.80 (95% CI 3.49-13.89)].

CONCLUSION

Our results suggest that IL7R rs6897932 is associated with MS in a southern Chinese population. More and larger MS studies to explore the genetic risk factors of MS are warranted.

Soluble IL-7Rα/sCD127 in Health, Disease, and Its Potential Role as a Therapeutic Agent

Soluble cytokine receptors can influence immune responses by modulating the biological functions of their respective ligands. These effects can be either agonistic or antagonistic and a number of soluble cytokine receptors have been shown to play critical roles in both maintenance of health and disease pathogenesis. Soluble IL-7Ra (sCD127) is one such example. With its impact on the IL-7/CD127 pathway, which is fundamental for the development and homeostasis of T cells, the role of sCD127 in health and disease has been extensively studied in recent years. Within this review, the role of sCD127 in maintaining host immune function is presented. Next, by addressing genetic factors affecting sCD127 expression and the associated levels of sCD127 production, the roles of sCD127 in autoimmune disease, infections and cancer are described. Finally, advances in the field of soluble cytokine therapy and the potential for sCD127 as a biomarker and therapeutic agent are discussed.

IL7RA genetic variants differentially affect IL-7Rα expression and alternative splicing: a role in autoimmune and infectious diseases?

Interleukin-7 receptor α chain (IL-7Rα) single nucleotide polymorphisms (SNPs) are associated with susceptibility to immunopathologies like autoimmune and inflammatory diseases. The current hypothesis about underlying mechanisms is based on the regulation of IL-7 availability for self-reactive T cells by influencing the generation of a soluble (s)IL-7Rα variant. This assumption was mainly predicated on the well-defined IL7RA SNP rs6897932, which affects alternative splicing and causes aberrant generation of the sIL-7Rα variant with potential effects on the IL-7 serum reservoir. However, more recent studies shed light on novel functions of autoimmunity risk-associated IL7RA SNPs and characterized the largely neglected effect of rs6897932 on membrane (m)IL-7Rα expression. These findings as well as a described role of impaired mIL-7Rα expression and IL7RA SNP influence on chronic infectious diseases necessitates the reevaluation of previous findings on the role of IL7RA SNPs in immunopathology.

IL7RA polymorphisms are not associated with AIDS progression

BACKGROUND

Our aim was to determine whether α-chain of the IL-7 receptor (IL7RA) polymorphisms (rs10491434, rs6897932 and rs987106) are associated with the clinical pattern of AIDS progression in ART-naïve HIV-infected patients.

MATERIALS AND METHODS

We carried out a cross-sectional study in 673 HIV-infected patients who were classified into three groups according to the clinical pattern of AIDS progression (188 long-term nonprogressors (LTNPs), 334 moderate progressors (MPs) and 151 rapid progressors (RPs)). Additionally, 134 healthy blood donors participated as a Control-group. We selected three IL7RA polymorphisms located at three regulatory regions [rs6897932 (exon 6), rs987106 (intronic region) and rs10491434 (3'UTR)]. DNA genotyping was performed using Sequenom's MassARRAY platform.

RESULTS

The Control-group and all HIV-infected patients had similar age and percentage of males. LTNP-group was older at HIV diagnosis and at the inclusion in the study and had higher percentage of intravenous drug users (IDU) (P < 0·001). Besides, LTNP-group had lower proportion of male patients and homosexual HIV transmission than MP and RP groups (P < 0·001). Moreover, similar values of allelic, genotypic and haplotype frequencies for IL7RA polymorphisms were found between healthy controls and HIV-infected patients (P > 0·05), and among different subgroups of HIV patients according to AIDS progression (LTNPs, MPs and RPs) (P > 0·05). The adjusted logistic regression did not show any significant association between IL7RA polymorphisms and AIDS progression.

CONCLUSIONS

IL7RA polymorphisms (rs6897932, rs987106 and rs10491434) were not associated with AIDS progression in Spanish population. Therefore, IL7RA polymorphisms do not seem to help us to understand HIV pathogenesis in untreated HIV-infected patients with different clinical evolution.

Gene variation in IL-7 receptor (IL-7R)α affects IL-7R response in CD4+ T cells in HIV-infected individuals

Optimal CD4+ T cell recovery after initiating combination antiretroviral treatment (cART) in HIV infection reduces risk of morbidity and mortality. T-allele homozygosity ('TT') in the single nucleotide polymorphism, rs6897932(C/T), in the IL-7 receptor α (IL-7RA) is associated with faster CD4+ T cell recovery after cART initiation compared to C-allele homozygosity in rs6897932 ('CC'). However, underlying mechanisms are unknown. We aimed to examine potential mechanisms explaining the association between rs6897932 and CD4+ T cell recovery. Ten 'TT' and 10 'CC' HIV-infected individuals matched on gender, age, and nadir and current CD4+ T cell counts were included in a cross-sectional study. 'TT' individuals had higher proportion of CD4+ T cells expressing pSTAT5 compared to 'CC' individuals after stimulating with IL-7, especially when co-stimulated with soluble IL7-RA (sIL-7RA). Furthermore, 'TT' individuals had a higher proportion of proliferating CD4+ T cells after 7 days of culture with IL-7 + sIL-7RA compared to 'CC' individuals. No differences between 'TT' and 'CC' in binding of biotinylated IL-7 were found. In conclusion, increased signal transduction and proliferation in response to IL-7 was found in 'TT' compared to 'CC' HIV-infected individuals providing a mechanistic explanation of the effect of rs6897932 T-allele on CD4+ T cell recovery in HIV infection.

No association between rs6897932 in the gene encoding interleukin-7 receptor α and low-grade inflammation or self-reported health - results from the Danish Blood Donor Study

The T-allele in the single nucleotide polymorphism rs6897932 in the gene encoding the IL-7 receptor α (IL7RA) is associated with reduced risk of autoimmune diseases including multiple sclerosis and also affects the course of HIV infection. Low-grade inflammation (LGI) and self-reported, health-related quality of life (HRQL) are often associated with chronic diseases and widely used in assessing and monitoring health status. The aim of the present study was to evaluate whether the T-allele in rs6897932 is associated with reduced risk of LGI (hsCRP 3-10 mg/L), history of infectious mononucleosis (IM), and HRQL in healthy individuals. A total of 17, 293 healthy Danish individuals from the Danish Blood Donor Study were included in the analyses. We tested rs6897932 as a predictor of LGI, self-reported IM, and HRQL in univariable and multivariable models stratified by sex. No associations between rs6897932 and LGI, self-reported IM or HRQL were found in men or women. This suggests that rs6897932 is not associated with general inflammation, and the reported associations between the T-allele in rs6897932 with several autoimmune diseases may be mediated through effects on a restricted part of the immune system.

Association between IL7RA polymorphisms and the successful therapy against HCV in HIV/HCV-coinfected patients

Interleukin-7 (IL-7) is a critical factor in maintaining or inducing effective antiviral CD4+ and CD8+ T-cell responses. The aim of this study was to examine the association of interleukin-7 receptor-α (IL7RA) polymorphisms with a sustained virologic response (SVR) after hepatitis C virus (HCV) therapy with pegylated interferon-alpha plus ribavirin (pegIFNα/ribavirin) in 177 human immunodeficiency virus (HIV)/HCV-coinfected patients. We performed a retrospective study in 177 naïve patients who started HCV treatment. The IL7RA rs6897932, rs987106, and rs3194051 polymorphisms were genotyped by the GoldenGate® assay. An SVR was defined as undetectable HCV viral load through 24 weeks after the end of HCV treatment. The highest SVR rate was found in patients with the rs6897932 CC (p = 0.029) and rs3194051 GG (p = 0.002) genotypes, and HCV genotypes 2/3 (GT2/3) infected patients with the rs987106 AA genotype (p = 0.048). Additionally, carriers of the rs3194051 GG genotype had a higher likelihood of achieving an SVR [adjusted odds ratio (aOR) = 5.32; 95 % confidence interval (CI) = 1.07-26.94; p = 0.040] than patients with the rs3194051 AA/AG genotype, while rs6897932 CC (aOR = 0.63; p = 0.205) and rs987106 AA (aOR = 0.60; p = 0.213) were not significant. Moreover, three major haplotypes were found: 46.6 % for CTA, 32.4 % for CAG, and 20.7 % for TAA haplotypes. Patients infected with GT2/3 and carriers of the CTA haplotype had lower odds of achieving an SVR (aOR = 0.08; p = 0.004) and the CAG haplotype (favorable alleles) had higher odds of achieving an SVR than other haplotypes (aOR = 21.96; p < 0.001). IL7RA polymorphisms seem to play a significant role in the virological response to pegIFNα/ribavirin therapy in HIV/HCV-coinfected patients, in particular among patients infected with HCV GT2/3.

Polymorphism in interleukin-7 receptor α gene is associated with faster CD4⁺ T-cell recovery after initiation of combination antiretroviral therapy

OBJECTIVES

To investigate single-nucleotide polymorphisms (SNPs) in the gene encoding interleukin-7 receptor α (IL7RA) as predictors for CD4⁺ T-cell change after initiation of combination antiretroviral therapy (cART) in HIV-infected whites.

DESIGN

SNPs in IL7RA were determined in the Danish HIV Cohort Study.

METHODS

CD4⁺ T-cell changes were estimated 6 months, 1, 2, and 5 years after initiation of cART in 1683 HIV-infected virally suppressed individuals. Five SNPs in IL7RA were examined as predictors for CD4⁺ T-cell change in the first (0-6 months after initiation of cART) and second phase (>6 months after initiation of cART) of immune recovery. Univariable and multivariable analyses including age, sex, calendar period, CD4⁺ nadir, and baseline CD4⁺ T-cell count and viral load as covariates were performed.

RESULTS

Individuals carrying two T-alleles in rs6897932 had faster CD4⁺ T-cell recovery compared with individuals carrying a C-allele in the first phase of immune recovery [mean CD4⁺ T-cell change, cells/μL (95% confidence interval), in TT: 177 (151-203), CT: 131 (119-143), CC: 141 (132-151), P = 0.018]. No isolated effect of rs6897932 on CD4⁺ T-cell change was found in the second phase of immune recovery; however, the initial difference in CD4⁺ T-cell recovery remained during 5 years. The effect was most pronounced in individuals above 40 years of age.

CONCLUSION

T-allele homozygosity in rs6897932 is a predictor for faster CD4⁺ T-cell recovery after initiation of cART in HIV-infected whites, however, only in the first phase of immune recovery.