Higher levels of IL-6, CD4 turnover and Treg frequency are already present before cART in HIV-infected subjects with later low CD4 recovery

Brief Report: In cART-Treated HIV-Infected Patients, Immunologic Failure Is Associated With a High Myeloid-Derived Suppressor Cell Frequency

BACKGROUND

During HIV infection, effective combined antiretroviral therapy suppresses viral replication and restores the number of circulating CD4+ T cells. However, 15%-30% of treated patients show a discordant response to combined antiretroviral therapy. Myeloid-derived suppressor cells (MDSC) are expanded in HIV+ patients; to better understand the role of MDSC on CD4 T-cell recovery, we evaluated the frequency of MDSC in HIV+ patients under combined antiretroviral therapy and its association with immunologic response.

METHODS

We enrolled 60 HIV+ patients, including complete responders (R, n = 44), virologic nonresponders (VNR, n = 5), and immunologic nonresponders (INR, n = 11). The frequency of circulating MDSC and the percentage of activated and naïve CD4 T cells were evaluated by flow cytometry. Plasmatic cytokine levels were analyzed by automated ELISA.

RESULTS

As previously observed, polymorphonuclear MDSC (PMN-MDSC) frequency was higher in HIV+ patients compared with healthy donors. Furthermore, PMN-MDSC percentage was higher in INR than R patients, and a significant association between MDSC frequency and immunologic failure was confirmed by a receiver operator characteristic analysis. Accordingly, an inverse correlation was found between the percentages of PMN-MDSC and naïve CD4 T cells. A positive correlation was observed between PMN-MDSC frequency and the percentage of human leucocyte antigen locus DR + CD4 T cells and the plasmatic level of IL-1β and IL-8.

CONCLUSION

Our results show that a high frequency of PMN-MDSC persists in INR, possibly because of immune activation, contributing to CD4 T-cell recovery failure. These findings further highlight the detrimental role of MDSC during HIV infection, suggesting these cells as a possible new therapeutic target.

Multi-omics in HIV: searching insights to understand immunological non-response in PLHIV

Antiretroviral therapy (ART) induces persistent suppression of HIV-1 replication and gradual recovery of T-cell counts, and consequently, morbidity and mortality from HIV-related illnesses have been significantly reduced. However, in approximately 30% of people living with HIV (PLHIV) on ART, CD4+ T-cell counts fail to normalize despite ART and complete suppression of HIV viral load, resulting in severe immune dysfunction, which may represent an increased risk of clinical progression to AIDS and non-AIDS events as well as increased mortality. These patients are referred to as "immune inadequate responders", "immunodiscordant responders" or "immune nonresponders (INR)". The molecular mechanisms underlying poor CD4+ T-cell recovery are still unclear. In this sense, the use of omics sciences has shed light on possible factors involved in the activity and metabolic dysregulation of immune cells during the failure of CD4+ T-cell recovery in INR. Moreover, identification of key molecules by omics approaches allows for the proposal of potential biomarkers or therapeutic targets to improve CD4+ T-cell recovery and the quality of life of these patients. Hence, this review aimed to summarize the information obtained through different omics concerning the molecular factors and pathways associated with the INR phenotype to better understand the complexity of this immunological status in HIV infection.

Cellular and molecular insights into incomplete immune recovery in HIV/AIDS patients

Highly active antiretroviral therapy (ART) can effectively inhibit virus replication and restore immune function in most people living with human immunodeficiency virus (HIV). However, an important proportion of patients fail to achieve a satisfactory increase in CD4⁺ T cell counts. This state is called incomplete immune reconstitution or immunological nonresponse (INR). Patients with INR have an increased risk of clinical progression and higher rates of mortality. Despite widespread attention to INR, the precise mechanisms remain unclear. In this review, we will discuss the alterations in the quantity and quality of CD4⁺ T as well as multiple immunocytes, changes in soluble molecules and cytokines, and their relationship with INR, aimed to provide cellular and molecular insights into incomplete immune reconstitution.

The Effect of protease inhibitors-based antiretroviral therapy on serum/plasma interleukin-6 levels among PLHIV: a systematic review and meta-analysis

INTRODUCTION

Recommended treatment regimen for HIV infection includes protease inhibitors/ritonavir (PIs/r) combined with two nucleoside reverse transcriptase inhibitors (2NRTIs), that enable to achieve and maintain viral suppression, restore and preserve immune function. However, there were inconsistent findings on the levels of interleukin-6 levels (IL-6).

METHODOLOGY

Systematic review and meta-analysis were performed to quantify the pooled effects of PIs/r-based ART on serum/plasma IL-6 levels in PLHIV. PubMed, Web of Science, and Embase were searched from the earliest record to November 4, 2020. Data analysis was conducted on Stata version 16 and Review Manager 5.3. A random-effect model was used to compute a pooled effect size and weighted mean difference (WMD) was considered the summary effect size. Heterogeneity between studies was estimated by Cochrane's Q test (chi-square test) and I-square statistic and subgroup analysis were performed to explore the source of heterogeneity.

RESULT

Initial search identified 3098 records and five studies (seven trials) met inclusion criteria. The pooled mean difference in serum/plasma IL-6 levels from baseline to follow-up was 0.534 pg/ml (95% CI: -0.012, 1.08, P=0.05, I² =76.4%). In subgroup analysis, there was a significant association between increased serum/plasma IL-6 levels, and age group ≥35 years old, baseline CD4⁺ counts <350 cell/mm³ , and mean viral load ≥ 4.5 log10 copies/ml.

CONCLUSION

We found that serum/plasma IL-6 levels increased after combined anti-retroviral therapy (cART) among treatment-naïve individuals who initiated a successful combination of PIs/r with 2NRTIs. This result also highlights the need to monitor serum/plasma IL-6 levels during antiviral therapy, which may aid in the effective future treatment of systemic inflammation and related disorders following elevated IL-6 levels. This article is protected by copyright. All rights reserved.

Chlorogenic acid ameliorated allergic rhinitis-related symptoms in mice by regulating Th17 cells

Allergic rhinitis (AR) is a non-infectious chronic inflammatory disease of nasal mucosa provoking T helper cell (Th) 17 response. Chlorogenic acid (CGA), one of the most abundant polyphenol compounds in various agricultural products, possesses antiviral, anti-inflammatory, and antibacterial properties. However, the effect of CGA on AR is unclear. Thus, our study explored the effect of CGA in modulating AR-related symptoms and immunoreaction, especially Th17 response. AR mice were induced by ovalbumin (OVA) administration and further treated with CGA or dexamethasone (Dex). The frequencies of rubbing and sneezing of AR mice were recorded. Histopathological analysis of nasal mucosa was conducted by Hematoxylin–Eosin and Periodic acid–Schiff stainings. The serum and nasal mucosa levels of OVA-immunoglobulin (Ig)E, interferon (IFN)-γ, retinoic acid-associated nuclear orphan receptor (ROR)-γt, and interleukin (IL)-17A were measured by enzyme-linked immunosorbent assay, quantitative reverse-transcription polymerase chain reaction (qRT-PCR), or Western blot. The ratio of CD4⁺IL-17⁺Th17 cells to CD4⁺ T cells in peripheral blood of AR mice was assessed by flow cytometer. CGA diminished the frequencies of rubbing and sneezing of AR mice in a concentration-dependent manner. CGA attenuated histopathological abnormalities and decreased goblet cell number in nasal mucosa of AR mice. CGA decreased the serum levels of OVA-IgE, ROR-γt, and IL-17A, while increasing the serum level of IFN-γ in AR mice. Meanwhile, CGA decreased the ratio of CD4⁺IL-17⁺Th17 cells to CD4⁺T cells in peripheral blood and the mRNA and protein levels of IL-17A and ROR-γt in AR mice. CGA ameliorated AR-related symptoms in mice by regulating Th17 cells, which could be a candidate for the treatment of AR.

Increased Frequencies of Myeloid-Derived Suppressor Cells Precede Immunodiscordance in HIV-Infected Subjects

Background

We have previously observed increased levels of inflammatory biomarkers and Th17 as well as Treg cells, but not other T-cell specific alterations, preceding immunodiscordance of successfully-treated HIV-infected subjects. Our hypothesis is that this could be related with potential alterations in myeloid-derived suppressor cells (MDSCs) and/or monocyte subsets.

Methods

We determined the frequencies of MDSCs and monocyte subsets and the expression of several functional markers (CCR2, β7-integrin, IDO, PDL1, CD11b) in HIV-infected subjects before treatment. We additionally analyzed follow-up samples after 24 months of suppressive cART in a subgroup of subjects. Bivariate regressions were performed, and correlations with soluble proinflammatory and bacterial translocation biomarkers, as well as with Th17/Treg ratio and anti-CMV titers were explored.

Results

Increased frequencies of MDSCs, but normal distribution of monocyte subsets, preceded immunodiscordance. The expression of several functional markers, such as CCR2, CD16, CD11b and PDL1, on MDSCs and monocyte subsets was altered in this scenario. MDSC and monocyte-related functional markers were associated with soluble biomarkers and T-cell parameters. Several of these cellular alterations were not restored after 24 months of suppressive cART.

Conclusion

An early immunosuppressive environment, characterized by the expansion of MDSCs and Tregs, precedes immunodiscordance and is related with a highly inflammatory status.

Definition of Immunological Nonresponse to Antiretroviral Therapy: A Systematic Review

BACKGROUND

Terms and criteria to classify people living with HIV on antiretroviral therapy who fail to achieve satisfactory CD4 T-cell counts are heterogeneous, and need revision and summarization.

METHODS

We performed a systematic review of PubMed original research articles containing a set of predefined terms, published in English between January 2009 and September 2018. The search retrieved initially 1360 studies, of which 103 were eligible. The representative terminology and criteria were extracted and analyzed.

RESULTS

Twenty-two terms and 73 criteria to define the condition were identified. The most frequent term was "immunological nonresponders" and the most frequent criterion was "CD4 T-cell count <350 cells/µL after ≥24 months of virologic suppression." Most criteria use CD4+ T-cell counts as a surrogate, either as an absolute value or as a change after a defined period of time [corrected]. Distinct values and time points were used. Only 9 of the 73 criteria were used by more than one independent research team. Herein we propose 2 criteria that could help to reach a consensus.

CONCLUSIONS

The high disparity in terms and criteria here reported precludes data aggregation and progression of the knowledge on this condition, because it renders impossible to compare data from different studies. This review will foster the discussion of terms and criteria to achieve a consensual definition.

Changes in peripheral blood inflammatory factors (TNF-α and IL-6) and intestinal flora in AIDS and HIV-positive individuals

OBJECTIVE

In this study, we investigated the changes in peripheral blood inflammatory factors and intestinal flora in acquired immune deficiency syndrome (AIDS) and human immunodeficiency virus (HIV)-positive individuals (AIDS/HIV patients), and explored the relationships among intestinal flora, peripheral blood inflammatory factors, and CD4+ T lymphocytes.

METHODS

Thirty blood and stool samples from an AIDS group and a control group were collected. The levels of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) were determined by enzyme-linked immunosorbent assay (ELISA), and the number of CD4+ T lymphocytes by a FACSCount automated instrument. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the messenger RNA (mRNA) levels of Bifidobacterium, Lactobacillus, Escherichia coli, Enterococcus faecalis, and Enterococcus faecium. Correlations among intestinal flora, inflammatory factor levels, and CD4+ T lymphocyte values were evaluated using the Spearman correlation coefficient.

RESULTS

The levels of TNF-α and IL-6 in the AIDS group were higher than those in the control group, while the number of CD4+ T lymphocytes was lower. The amounts of Bifidobacterium and Lactobacillus in the AIDS group were significantly lower than those in control group, while the amounts of E. coli, E. faecalis, and E. faecium were much higher. The amounts of Bifidobacterium and Lactobacillus were negatively correlated with the content of TNF-α and IL-6 and the CD4+ T lymphocyte count, while those correlations were reversed for E. coli, E. faecalis, and E. faecium.

CONCLUSIONS

The intestinal microbiota of AIDS/HIV patients were disordered, and there was a correlation between the amount of intestinal flora and the number of CD4+ T lymphocytes and the levels of TNF-α and IL-6.

New signatures of poor CD4 cell recovery after suppressive antiretroviral therapy in HIV-1-infected individuals: involvement of miR-192, IL-6, sCD14 and miR-144

Up to 40% of newly diagnosed cases of HIV-1 infection are late diagnoses, with a profound decrease in CD4 cell counts in many cases. One-third of these individuals do not achieve optimal CD4 cell recovery (OR) after suppressive antiretroviral treatment (ART). This retrospective/longitudinal study of poor recovery (PR) included 79 HIV-1-infected individuals with CD4 count <200 cells/mm³ (25 PR and 54 OR) before ART. After suppressive ART, 21 PR and 24 OR individuals were further analysed, including paired samples. Selected miRs and plasma inflammatory markers were determined to investigate their potential predictive/diagnostic value for poor recovery. miR-192, IL-6 and sCD14 were independently associated with CD4 recovery before ART (p = 0.031, p = 0.007, and p = 0.008, respectively). The combination of these three factors returned a good discrimination (predictive value for PR) value of 0.841 (AUC, p < 0.001). After suppressive ART, miR-144 was independently associated with CD4 recovery (p = 0.017), showing a moderate discrimination value of 0.730 (AUC, p = 0.008) for PR. Our study provides new evidence on the relationship between miRs and HIV-1 infection that could help improve the management of individuals at HIV-1 diagnosis. These miRs and cytokines signature sets provide novel tools to predict CD4 cell recovery and its progression after ART.

Incomplete immune reconstitution in HIV/AIDS patients on antiretroviral therapy: Challenges of immunological non-responders

The morbidity and mortality of HIV type-1 (HIV-1)-related diseases were dramatically diminished by the grounds of the introduction of potent antiretroviral therapy, which induces persistent suppression of HIV-1 replication and gradual recovery of CD4⁺ T-cell counts. However, ∼10-40% of HIV-1-infected individuals fail to achieve normalization of CD4⁺ T-cell counts despite persistent virological suppression. These patients are referred to as "inadequate immunological responders," "immunodiscordant responders," or "immunological non-responders (INRs)" who show severe immunological dysfunction. Indeed, INRs are at an increased risk of clinical progression to AIDS and non-AIDS events and present higher rates of mortality than HIV-1-infected individuals with adequate immune reconstitution. To date, the underlying mechanism of incomplete immune reconstitution in HIV-1-infected patients has not been fully elucidated. In light of this limitation, it is of substantial practical significance to deeply understand the mechanism of immune reconstitution and design effective individualized treatment strategies. Therefore, in this review, we aim to highlight the mechanism and risk factors of incomplete immune reconstitution and strategies to intervene.

Glutaminolysis and lipoproteins are key factors in late immune recovery in successfully treated HIV-infected patients

The immunological, biochemical and molecular mechanisms associated with poor immune recovery are far from known, and metabolomic profiling offers additional value to traditional soluble markers. Here, we present novel and relevant data that could contribute to better understanding of the molecular mechanisms preceding a discordant response and HIV progression under suppressive combined antiretroviral therapy (cART). Integrated data from nuclear magnetic resonance (NMR)-based lipoprotein profiles, mass spectrometry (MS)-based metabolomics and soluble plasma biomarkers help to build prognostic and immunological progression tools that enable the differentiation of HIV-infected subjects based on their immune recovery status after 96 weeks of suppressive cART. The metabolomic signature of ART-naïve HIV subjects with a subsequent late immune recovery is the expression of pro-inflammatory molecules and glutaminolysis, which is likely related to elevate T-cell turnover in these patients. The knowledge about how these metabolic pathways are interconnected and regulated provides new targets for future therapeutic interventions not only in HIV infection but also in other metabolic disorders such as human cancers where glutaminolysis is the alternative pathway for energy production in tumor cells to meet their requirement of rapid proliferation.

Thymic Function as a Predictor of Immune Recovery in Chronically HIV-Infected Patients Initiating Antiretroviral Therapy

Poor immunological responders (PIR) are HIV-infected patients with virologic suppression upon antiretroviral therapy (ART) but persistently low CD4⁺ T cell counts. Early identification of PIR is important given their higher morbimortality compared to adequate immune responders (AIR). In this study, 33 patients severely lymphopenic at ART onset, were followed for at least 36 months, and classified as PIR or AIR using cluster analysis grounded on their CD4⁺ T cell count trajectories. Based on a variety of immunological parameters, we built predictive models of PIR/AIR outcome using logistic regression. All PIR had CD4⁺ T cell counts consistently below 500 cells/μL, while all AIR reached this threshold. AIR showed a higher percentage of recent thymic emigrants among CD4⁺ T cells; higher numbers of sj-TRECs and greater sj/β TREC ratios; and significant increases in thymic volume from baseline to 12 months of ART. We identified mathematical models that correctly predicted PIR/AIR outcome after 36 months of therapy in 77-87% of the cases, based on observations made until 2-6 months after ART onset. This study highlights the importance of thymic activity in the immune recovery of severely lymphopenic patients, and may help to select the patients that will benefit from closer follow-up or novel therapeutic approaches.

Clinical characteristics of HIV-1-infected patients with high levels of plasma interferon-γ: a multicenter observational study

Background

Circulating interferon-γ (IFN-γ) concentration may be sustained at a high level regardless of the initiation of antiretroviral therapy (ART) in some patients with HIV-1 infection. In the present study, we examined the clinical characteristics of HIV-1-infected patients with high levels of plasma IFN-γ.

Methods

The study subjects were patients infected with HIV-1 who were either naïve to ART with CD4⁺ cell count > 200 cells/μL (n = 12), or had achieved viral suppression after ART for over a year (n = 188). The levels of plasma IFN-γ and interleukin-6 (IL-6) were measured by the enzyme-linked immunosorbent assay. Patients were divided into high IFN-γ and low IFN-γ groups based on a cutoff level of 5 pg/mL.

Results

The high IFN-γ group included 41 patients (21%). Compared to the patients on ART with low IFN-γ levels, those on ART in the high IFN-γ group were more likely to be younger than 50 years of age (P = 0.0051) and less likely to have dyslipidemia (P = 0.0476) or to be on a protease inhibitor (P = 0.0449). There was no significant difference between groups in the median increase of CD4⁺ cell counts from the initiation of ART for up to 3 years. However, after 4 years, the increase in CD4⁺ cell counts was significantly lower in the high IFN-γ group compared with that in the low IFN-γ group. There were no such significant differences between patients with low and high (> 2 pg/mL) levels of plasma IL-6.

Conclusion

We concluded that HIV-1-infected patients with high levels of circulating IFN-γ did not have a higher rate of comorbidities related to immune activation. However, they exhibited lower CD4⁺ cell count recovery after 4 years of being on ART. This deficit could be a consequence of persistent immune activation.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3643-2) contains supplementary material, which is available to authorized users.

Nonhuman Primate Models and Understanding the Pathogenesis of HIV Infection and AIDS

Research using nonhuman primates (NHPs) as models for human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS) has resulted in tremendous achievements not only in the prevention and treatment of HIV, but also in biomedical research more broadly. Once considered a death sentence, HIV infection is now fairly well controlled with combination antiretroviral treatments, almost all of which were first tested for efficacy and safety in nonhuman primates or other laboratory animals. Research in NHP has led to "dogma changing" discoveries in immunology, infectious disease, and even our own genetics. We now know that many of our genes are retroviral remnants, or developed in response to archaic HIV-like retroviral infections. Early studies involving blood from HIV patients and in experiments in cultured tissues contributed to confusion regarding the cause of AIDS and impeded progress in the development of effective interventions. Research on the many retroviruses of different NHP species have broadened our understanding of human immunology and perhaps even our origins and evolution as a species. In combination with recent advances in molecular biology and computational analytics, research in NHPs has unique potential for discoveries that will directly lead to new cures for old human and animal diseases, including HIV/AIDS.

HIV-Infected Subjects With Poor CD4 T-Cell Recovery Despite Effective Therapy Express High Levels of OX40 and α4β7 on CD4 T-Cells Prior Therapy Initiation

Background

HIV-infected subjects with suboptimal CD4 restoration despite suppressive combined antiretroviral treatment (cART) (immunodiscordant subjects) have been classically characterized after a variable period of time under cART. Recently, we have reported that an increased frequency of proliferating CD4 T-cells in these subjects is already present before the cART onset. The potential contribution of peripheral compensatory homeostatic proliferation (HP) is yet unknown. We aimed to analyze the expression of HP-related cellular markers on CD4 T-cells of immunodiscordant subjects before cART.

Methods

We analyzed the expression of OX40 and α4β7 on peripheral CD4 T-cells from immunodiscordant and control subjects (n = 21 each group) before cART initiation, and also on available follow-up samples (after 24 month of suppressive cART). Additionally, we tested the expression of these markers in an in vitro system for the study of human HP processes.

Results

Immunodiscordant subjects showed increased levels of OX40 and α4β7 on CD4 T-cells before cART initiation. While the cART tended to reduce these levels, immunodiscordant subjects still maintained comparatively higher levels of OX40 and α4β7 after 24 months under suppressive cART. These HP-related markers were upregulated in vitro during the human HP, especially during the fast HP.

Conclusion

Our results are compatible with exacerbated HP processes in immunodiscordant subjects, already before the cART onset.

The impact of antiretroviral therapy on iron homeostasis and inflammation markers in HIV-infected patients with mild anemia

Background

Anemia is frequent during HIV infection and is predictive of mortality. Although cART has demonstrated to reduce its prevalence, several patients still experience unresolved anemia. We aimed to characterize iron homeostasis and inflammation in HIV-infected individuals with mild anemia in relation to cART.

Methods

In this retrospective cohort study, HIV-infected patients with mild anemia, CD4⁺ cells > 200/mm³ at baseline, maintaining virological response for 12 months after cART starting were selected within the Standardized Management of Antiretroviral Therapy Cohort (MASTER) cohort. Several inflammation and immune activation markers and iron homeostasis indexes were measured in stored samples, obtained at cART initiation (T0) and 12 months later (T1). Patients were grouped on the basis of hemoglobin values at T1: group A (> 13 g/dl) and B (< 13 g/dl). Wilcoxon rank sum test was used to compare biomarker values. Pearson correlation coefficients were calculated for all variables.

Results

cART improved CD4⁺ and CD8⁺ cell counts and their ratio, but this effect was significant only in group A. Only these patients had mild iron deficiency at T0 and showed higher transferrin and lower percentage of transferrin saturation than patients of group B, but differences disappeared with cART. cART decreased inflammation in all patients, but group B had higher levels of all markers than group A, reaching statistical significance only for IL-8 values at T1 (16 vs 2.9 pg/ml; p = 0.017). Hepcidin and IL-6 levels did not show significant differences between groups. Hemoglobin levels both at T0 and T1 did not correlate with any marker.

Conclusions

Baseline mild anemia in HIV-infected patients cannot always be resolved with durable efficient cART, possibly due to residual inflammation or immune activation rather than unbalanced iron homeostasis. Further research is needed on cytokine profiling to understand the mechanisms that induce anemia in HIV with suppressive cART.

Electronic supplementary material

The online version of this article (10.1186/s12967-017-1358-6) contains supplementary material, which is available to authorized users.

Increased frequencies of Th17 cells and IL17a-producing regulatory T-cells preceding the immunodiscordant response to antiretroviral treatment

BACKGROUND

Despite the fact that antiretroviral therapy (cART) suppresses HIV-viremia, an adequate CD4 T-cell recovery is not always achieved (immunodiscordant response to cART). IL17a-producing CD4 T-cells (Th17) constitutes an important subset involved in the preservation of mucosal surfaces integrity, which depletion has been associated with disease progression in HIV-infection. However, whether Th17 frequency at cART initiation is associated with a poor CD4 T-cell recovery has not been yet explored. Our aim was to explore whether the Th17 cells and other IL17a-producing T-cell subsets at cART initiation were associated with a subsequent immunodiscordant response to cART.

METHODS

We selected pre-cART samples of antiretroviral-naïve subjects with and without a low CD4 recovery after cART (LR-subjects and HR-subjects, respectively). Peripheral blood mononuclear cells (PBMCs) were stimulated with PMA/ionomycine, and the production of several cytokines including IL17a was analyzed by flow cytometry.

RESULTS

A trend to higher Th17 (p = 0.05) and increased frequencies of IL17a-producing Treg (p = 0.011) was found in LR-subjects before cART onset. Despite increased frequencies of both Treg and Th17 in LR-subject at cART initiation, no alteration of Treg/Th17 ratio was observed. While polifunctional profile of CD4 T-cells was not different, frequencies of CD4 T-cells producing cytokine-combinations including IL17a were increased in LR-subjects.

CONCLUSION

Increased frequencies of Th17, IL17a-producing Treg and CD4 T-cells producing specific IL17a-containing combinations of cytokines, precede the immunodiscordant response to cART, suggesting a potential contribution of these subsets in such anomalous response to cART.

A Lower Baseline CD4/CD8 T-Cell Ratio Is Independently Associated with Immunodiscordant Response to Antiretroviral Therapy in HIV-Infected Subjects

We explored if baseline CD4/CD8 T-cell ratio is associated with immunodiscordant response to antiretroviral therapy in HIV-infected subjects. Comparing immunodiscordant and immunoconcordant subjects matched by pretreatment CD4 counts, we observed a lower pretreatment CD4/CD8 T-cell ratio in immunodiscordant subjects. Furthermore, pretreatment CD4/CD8 T-cell ratio, but not CD4 counts, correlated with the main immunological alterations observed in immunodiscordants, including increased regulatory T-cell (Treg) frequency and T-cell turnover-related markers. Then, in a larger cohort, only baseline CD4/CD8 T-cell ratio was independently associated with immunodiscordance, after adjusting by the viral CXCR4-tropic HIV variants. Our results suggest that the CD4/CD8 T-cell ratio could be an accurate biomarker of the subjacent immunological damage triggering immunodiscordance.