High frequency of CD8 escape mutations in elite controllers as new obstacle for HIV cure.

Accumulation of mutations in epitopes of cytolytic-T-lymphocytes immune response (CTL) in HIV-reservoir seems to be one of the reasons for shock-and-kill strategy failure. Ten non-controller patients on successful cART (TX) and seven elite controllers (EC) were included. HIV-Gag gene from purified resting memory CD4+ T-cells was sequenced by Next-Generation-Sequencing. HLA class-I alleles were typed to predict optimal HIV-Gag CTL epitopes. For each subject, the frequency of mutated epitopes in the HIV-Gag gene, the proportion of them considered as CTL-escape variants as well as their effect on antigen recognition by HLA were assessed. The proportion (%) of mutated HIV-Gag CTL epitopes in the reservoir was high and similar in EC and TX (86%[50-100] and 57%[48-82] respectively, p=0.315). Many of them were predicted to negatively impact antigen recognition. Moreover, the proportion of mutated epitopes considered to be CTL-escape variants was also similar in TX and EC (77%[49-92] vs. 50%[33-75] respectively, p=0.117). Thus, the most relevant finding of our study was the high and similar proportions of HIV-Gag CTL-escape mutations in the reservoir of both HIV-noncontroller patients with cART (TX) and patients with spontaneous HIV-control (EC). Our findings suggest that escape mutations of CTL-response may be another obstacle to eliminate the HIV reservoir and constitute a proof of concept that challenges HIV cure strategies focused on the reactivation of reservoirs. Due to the small sample size that could impact the robustness of the study, further studies with larger cohorts of elite controller patients are needed to confirm these results.

HIV-reservoir size is not affected either by HCV coinfection or by direct acting antivirals (DAAs) therapy.

The role of HCV on the HIV reservoir is controversial since the reduction on HIV-DNA levels after HCV eradication with IFNα/RBV treatment seems to be the result of drugs instead of HCV clearance. We assessed whether HCV eradication can decrease HIV-DNA content in HIV/HCV-coinfected patients treated with direct-acting antivirals, DAAs (IFNα/RBV-free regimens). Cell-associated HIV-DNA was measured by ddPCR in 25 HIV-monoinfected and 25 HIV/HCV-coinfected patients. There were no differences in HIV-DNA levels between groups neither at baseline nor at 12 weeks after DAAs treatment completion. Our results indicate that HCV does not appear to influence the HIV reservoir size and suggest the lack of an anti-HIV action for DAAs.

Extracellular Vesicles as a New Promising Therapy in HIV Infection.

Combination antiretroviral therapy (cART) effectively blocks HIV replication but cannot completely eliminate HIV from the body mainly due to establishment of a viral reservoir. To date, clinical strategies designed to replace cART for life and alternatively to eliminate the HIV reservoir have failed. The reduced expression of viral antigens in the latently infected cells is one of the main reasons behind the failure of the strategies to purge the HIV reservoir. This situation has forced the scientific community to search alternative therapeutic strategies to control HIV infection. In this regard, recent findings have pointed out extracellular vesicles as therapeutic agents with enormous potential to control HIV infection. This review focuses on their role as pro-viral and anti-viral factors, as well as their potential therapeutic applications.

Both HCV Infection and Elevated Liver Stiffness Significantly Impacts on Several Parameters of T-Cells Homeostasis in HIV-Infected Patients.

(1) Background: The role of hepatitis C virus (HCV) co-infection on the T-cell homeostasis disturbances in human immunodeficiency virus (HIV)-infected patients as well as its reversion after HCV eradication with direct acting antivirals (DAAs) therapy has not been yet clarified. We extensively analyzed the effect of HCV co-infection on immune parameters of HIV pathogenesis and its evolution after HCV eradication with DAAs. (2) Methods: Seventy individuals were included in the study-25 HIV-monoinfected patients, 25 HIV/HCV-coinfected patients and 20 HIV and HCV seronegative subjects. All patients were on antiretroviral therapy and undetectable HIV-viremia. Immune parameters, such as maturation, activation, apoptosis, senescence and exhaustion of T-cells were assessed by flow cytometry. Cross-sectional and longitudinal (comparing pre- and post-DAAs data in HIV/HCV coinfected patients) analyses were performed. Univariate and multivariate (general linear model and canonical discriminant analysis -CDA-) analyses were used to assess differences between groups. (3) Results-The CDA was able to clearly separate HIV/HCV coinfected from HIV-monoinfected patients, showing a more disturbed T-cells homeostasis in HIV/HCV patients, especially activation and exhaustion of T-cells. Interestingly, those perturbations were more marked in HIV/HCV patients with increased liver stiffness. Eradication of HCV with DAAs restored some but not all the T-cells homeostasis disturbances, with activation and exhaustion of effector CD8 T-cells remaining significantly increased three months after HCV eradication. (4) Conclusions-HCV co-infection significantly impacts on several immune markers of HIV pathogenesis, especially in patients with increased liver stiffness. Eradication of HCV with DAAs ameliorates but does not completely normalize these alterations. It is of utmost relevance to explore other mechanisms underlying the immune damage observed in HIV/HCV coinfected patients with control of both HIV and HCV replication.

Elite controllers: A heterogeneous group of HIV-infected patients.

The exceptional group of ECs has been of great help, and will continue to provide invaluable insight with regard to reach a potential functional cure of HIV. However, there is no consensus on the immune correlates associated to this EC phenotype which preclude reaching a potential functional cure of HIV. The existing literature studying this population of individuals has indeed revealed that they are a very heterogeneous group regarding virological, immunological, and even clinical characteristics, and that among ECs only a very small proportion are homogeneous in terms of maintaining virological and immunological control in the long term (the so-called long-term elite controllers, LTECs). Thus, it is of pivotal relevance to identify the LTECs subjects and use them as the right model to redefine immune correlates of a truly functional cure. This review summarizes the evidence of the heterogeneity of HIV elite controllers (ECs) subjects in terms of virological, immunological and clinical outcomes, and the implications of this phenomenon to adequately consider this EC phenotype as the right model of a functional cure.

Liver Stiffness Hinders Normalization of Systemic Inflammation and Endothelial Activation after Hepatitis C Virus (HCV) Eradication in HIV/HCV Coinfected Patients.

Systemic inflammation, endothelial dysfunction and coagulopathy are of high clinical relevance in the management of people living with HIV (PLWH), and even more in patients coinfected with hepatitis C virus (HCV). It has been suggested a significant impact of HCV coinfection on these conditions. However, HCV can be eradicated in most patients with the new direct-acting antivirals (DAAs) therapy. We have analyzed the effect of HCV on systemic inflammation, endothelial activation and coagulopathy in PLWH and its evolution after HCV eradication with DAAs. Twenty-five HIV/HCV coinfected (HIV/HCV group), 25 HIV monoinfected (HIV group) and 20 healthy controls (HC) were included in the study. All patients were on ART and HIV suppressed. Levels of fourteen markers of systemic inflammation, endothelial activation and coagulopathy (IL-1ß, IL-6, IL-12p70, IL-8, TNFα, D-dimer, Eotaxin, IL-18, IP-10, monocyte chemotactic protein-1 (MCP-1), plasminogen activator inhibitor-1 (PAI-1), TNFα receptor 1 (TNFR1), vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1)) were measured on plasma at baseline and after DAAs-mediated HCV eradication. Non-parametric tests were used to establish inter/intra-group differences. At baseline, the HIV/HCV group showed increased levels of IL-18 (p = 0.028), IP-10 (p < 0.0001), VCAM-1 (p < 0.0001) and ICAM-1 (p = 0.045), compared to the HC and HIV groups, with the highest levels for IL18 and IP10 observed in HIV/HCV patients with increased liver stiffness (≥7.1 KPa). Eradication of HCV with DAAs-based therapy restored some but not all the evaluated parameters. VCAM-1 remained significantly increased compared to HC (p = 0.001), regardless of the level of basal liver stiffness in the HIV/HCV group, and IP-10 remained significantly increased only in the HIV/HCV group, with increased level of basal liver stiffness compared to the HC and to the HIV groups (p = 0.006 and p = 0.049, respectively). These data indicate that DAAs therapy in HIV/HCV co-infected patients and HCV eradication does not always lead to the normalization of systemic inflammation and endothelial dysfunction conditions, especially in cases with increased liver stiffness.

Transcriptional signature of resting-memory CD4 T cells differentiates spontaneous from treatment-induced HIV control.

The HIV reservoir is the main barrier to eradicating HIV infection, and resting memory CD4 T (Trm) cells are one of the most relevant cellular component harboring latent proviruses. This is the first study analyzing the transcriptional profile of Trm cells, in two well-characterized groups of HIV patients with distinct mechanisms of viral replication control (spontaneous versus treatment-induced). We use a systems biology approach to unravel subtle but important differences in the molecular mechanisms operating at the cellular level that could be associated with the host's ability to control virus replication and persistence. Despite the absence of significant differences in the transcriptome of Trm cells between Elite Controllers (ECs) and cART-treated (TX) patients at the single gene level, we found 353 gene ontology (GO) categories upregulated in EC compared with TX. Our results suggest the existence of mechanisms at two different levels: first boosting both adaptive and innate immune responses, and second promoting active viral replication and halting HIV latency in the Trm cell compartment of ECs as compared with TX patients. These differences in the transcriptional profile of Trm cells could be involved in the lower HIV reservoir observed in ECs compared with TX individuals, although mechanistic studies are needed to confirm this hypothesis. Combining transcriptome analysis and systems biology methods is likely to provide important findings to help us in the design of therapeutic strategies aimed at purging the HIV reservoir. KEY MESSAGES: HIV-elite controllers have the lowest HIV-DNA content in resting memory CD4 T cells. HIV-ECs show a particular transcriptional profile in resting memory CD4 T cells. Molecular mechanisms of enhanced adaptative and innate immune response in HIV-ECs. High viral replication and low viral latency establishment associate to the EC status.

IL7RA rs6897932 Polymorphism is Associated with Better CD4+ T-Cell Recovery in HIV Infected Patients Starting Combination Antiretroviral Therapy.

Interleukin-7 receptor subunit alpha (IL7RA) rs6897932 polymorphism is related to CD4+ recovery after combination antiretroviral therapy (cART), but no studies so far have analyzed its potential impact in patients with very low CD4+ T-cells count. We aimed to analyze the association between IL7RA rs6897932 polymorphism and CD4+ T-cells count restoration in HIV-infected patients starting combination antiretroviral therapy (cART) with CD4+ T-cells count <200 cells/mm3. We performed a retrospective study in 411 patients followed for 24 months with a DNA sample available for genotyping. The change in CD4+ T-cells count during the follow-up was considered as the primary outcome. The rs6897932 polymorphism had a minimum allele frequency (MAF) >20% and was in Hardy-Weinberg equilibrium (p = 0.550). Of 411 patients, 256 carried the CC genotype, while 155 had the CT/TT genotype. The CT/TT genotype was associated with a higher slope of CD4+ T-cells recovery (arithmetic mean ratio; AMR = 1.16; p = 0.016), higher CD4+ T-cells increase (AMR = 1.19; p = 0.004), and higher CD4+ T-cells count at the end of follow-up (AMR = 1.13; p = 0.006). Besides, rs6897932 CT/TT was related to a higher odds of having a value of CD4+ T-cells at the end of follow-up ≥500 CD4+ cells/mm3 (OR = 2.44; p = 0.006). After multiple testing correction (Benjamini-Hochberg), only the increase of ≥ 400 CD4+ cells/mm3 lost statistical significance (p = 0.052). IL7RA rs6897932 CT/TT genotype was related to a better CD4+ T-cells recovery and it could be used to improve the management of HIV-infected patients starting cART with CD4+ T-cells count <200 cells/mm3.

Genetic variation in CCR2 and CXCL12 genes impacts on CD4 restoration in patients initiating cART with advanced immunesupression.

OBJECTIVE: We investigated the association of genetic polymorphisms in chemokine and chemokine receptor genes with poor immunological recovery in HIV patients starting combined antiretroviral therapy (cART) with low CD4 T-cell counts. METHODS: A case-control study was conducted in 412 HIV-infected patients starting cART with CD4 T-cell count <200 cells/µL and successful viral control for two years. CD4 count increase below 200 cells/µL after two years on cART was used to define INR (immunological non-responder) patients. Polymorphisms in CXCL12, CCL5 and CCR2 genes were genotyped using sequenom's MassARRAY platform. RESULTS: Thirty two percent (134/412) of patients were classified as INR. After adjusting by age, route of HIV infection, length of infection before cART and viral hepatitis coinfection, CCR2 rs1799864-AG genotype was significantly associated with INR status (OR [95% CI]: 1.80 [1.04-3.11]; p = 0.04), and CXCL12 rs1801157-TT genotype showed a trend (OR [95% CI]: 2.47 [0.96-6.35]; p = 0.06). CONCLUSIONS: CCR2 rs1799864-AG or CXCL12 rs1801157-TT genotypes influence on the probability of poor CD4 recovery in the population of HIV patients starting cART with low CD4 counts. Genotyping of these polymorphisms could be used to estimate the risk of poor CD4 restoration, mainly in patients who are diagnosed late in the course of infection.