Sustained Virologic Control Research Articles

A positive affect intervention alters leukocyte DNA methylation in sexual minority men with HIV who use methamphetamine

ObjectiveThis epigenomics sub-study embedded within a randomized controlled trial examined whether an evidenced-based behavioral intervention model that decreased stimulant use altered leukocyte DNA methylation (DNAm). MethodsSexual minority men with HIV who use methamphetamine were randomized to a five-session positive affect intervention (n = 32) or an attention-control condition (n = 21), both delivered during three months of contingency management for stimulant abstinence. All participants exhibited sustained HIV virologic control – an HIV viral load less than 40 copies/mL at baseline and six months post-randomization. The Illumina EPIC BeadChip measured leukocyte methylation of cytosine-phosphate-guanosine (CpG) sites mapping onto five a priori candidate genes of interest (i.e., ADRB2, BDNF, FKBP5, NR3C1, OXTR). Functional DNAm pathways and soluble markers of immune dysfunction were secondary outcomes. ResultsCompared to the attention-control condition, the positive affect intervention significantly decreased methylation of CpG sites on genes that regulate β2 adrenergic and oxytocin receptors. There was an inconsistent pattern for the direction of the intervention effects on methylation of CpG sites on genes for glucocorticoid receptors and brain-derived neurotrophic factor. Pathway analyses adjusting for the false discovery rate (padj < 0.05) revealed significant intervention-related alterations in DNAm of Reactome pathways corresponding to neural function as well as dopamine, glutamate, and serotonin release. Positive affect intervention effects on DNAm were accompanied by significant reductions in the self-reported frequency of stimulant use. ConclusionsThere is an epigenetic signature of an evidence-based behavioral intervention model that reduced stimulant use, which will guide the identification of biomarkers for treatment responses.

High mortality following early initiation of antiretroviral therapy in infants living with HIV from three African countries

Even with increasing access to rapid HIV diagnosis and early antiretroviral therapy (ART) initiation, infants living with HIV seem to have adverse outcomes. We assessed the probability of death, viral suppression, and other HIV-related events in the first three years of life among early-treated children with perinatally-acquired HIV in South Africa, Mozambique, and Mali. We enrolled a cohort of infants who initiated ART within the initial 6 months of life and within 3 months of diagnosis. These children were monitored 2, 6, 12 and 24 weeks after enrolment, followed by biannual check-ups up to 4 years after enrolment. We assessed the probability of death, viral load (VL) suppression, severe immunosuppression (according to WHO guidelines), and engagement in care using Kaplan-Meier plots, and hazard ratios for these outcomes using multivariable Cox regression models. Two hundred and fifteen infants were enrolled and monitored for a median of 34 months [IQR, 16.3; 44.1]. ART initiation occurred at a median of 34 days of age [IQR, 26.0; 73.0]. The probability of death at 1 year of ART was 10% (95% CI, 6-14), increased to 12% (95% CI, 8-17) at 2 and remained in 12% at 3 years. The main risk factor for HIV/AIDS-related mortality was baseline viral load [HR: 2.98 (95% CI, 1.25-7.12)]. Sixty-one of 146 (42%) children achieved sustained virological control below lower limit of detection for any ≥1 year period between enrolment and 4 years after enrolment. Viral suppression during follow-up was inversely associated with baseline viral load [Hazard Ratio (HR): 0.72 (95% CI, 0.58-0.89] and adverse maternal social events [HR: 0.26 (95% CI, 0.15-0.45)]. Adherence to ART was assessed as optimal in 81% of the visits. Female sex at birth, lower age at diagnosis and maternal adverse social life events were risk factors for low adherence [Odds ratio, OR 1.25 (95% CI, 1.00-1.56); 1.12 (95% CI, 1.01-1.27) and 2.52 (95% CI, 2.16-12.37), respectively]. Despite early ART, mortality remains high in infants. High baseline VL and adverse maternal social environment increased the risk of poor outcomes. Sustained supportive strategies are essential during and after pregnancy, to achieve better survival. Early Treated Perinatally HIV Infected Individuals: Improving Children's Actual Life (EPIICAL) is a research consortium funded by ViiV Healthcare and led by Penta Foundation. The funder was not involved in the analysis and interpretation of data, writing of the report, or the decision to submit the paper for publication. The corresponding authors had access to all data and take final responsibility for the decision to submit.

A follow-up study: 6-year cART-free virologic control of rhesus macaques after PD-1-based DNA vaccination against pathogenic SHIVSF162P3CN challenge.

An effective vaccine for combination antiretroviral therapy (cART)-free virologic control of HIV-1 by enhancing antigen-specific effector-memory CD8+ T lymphocytes could be useful in controlling the AIDS pandemic. Previously, we demonstrated that a programmed death-1 (PD-1)-based DNA vaccine, pRhPD1-p27, was effective in inducing Gag-p27-specific effector-memory CD8+ T cells for viremia suppression in rhesus macaques infected with pathogenic SHIVSF162P3CN for 2 years. In this follow-up study, we report on two pRhPD1-p27-vaccinated and SHIVSF162P3CN-infected macaques that have remained alive to date with undetectable viremia levels and low proviral loads over 6 years in the absence of cART, achieving a state of sustained virologic control. Polyfunctional effector-memory Gag-p27-specific T cells were maintained in these macaques. Moreover, several T cell epitopes found at 6 years post-viral challenge were identical to those induced during the vaccination phase, indicating sustained vaccine-induced memory T cell responses. The viral challenge resulted in de novo Nef-specific T cell responses, which were also maintained. These Gag-p27- and Nef-specific T cell responses were stronger than those in some SHIVSF162P3CN-infected macaques that showed viremia control after experimental therapy using a tandem bispecific neutralizing antibody. Our findings indicate that the PD-1-based DNA vaccine strategy holds promise as a clinical immunotherapy for long-term HIV-1 suppression.IMPORTANCEEfficient strategies for HIV-1 cART-free virologic control are critical for ending the AIDS pandemic. The essential role of effector-memory CD8+ T cells in controlling viremia and eliminating virus-infected cells has made them a promising target for vaccine development. It has been previously reported that PD-1-based DNA vaccination was effective in inducing polyfunctional effector-memory CD8+ T cells for AIDS virus control for 2 years in rhesus monkeys. This follow-up study extends the findings and shows that a viremia-free period of over 6 years was detected in two monkeys immunized with PD-1-based DNA vaccine against pathogenic SHIVSF162P3CN infection in the absence of antiretroviral therapy. Long-term vaccine-induced memory T cell responses were detected. Our results warrant the clinical trials of PD-1-based DNA vaccines for achieving HIV-1 cART-free virologic control used either alone or in combination with other biomedical interventions.

Coordination of inflammatory responses in children with perinatally acquired HIV infection.

We investigated dynamics of inflammatory biomarkers in children with perinatally acquired HIV (PHIV) who started antiretrovirals at age less than 3 years and achieved sustained virologic control (HIV plasma RNA <400 copies/ml). This was a retrospective analysis of inflammatory biomarkers in children enrolled in a randomized trial of early (<3 years of age) PI-based versus NNRTI-based regimens (P1060), who achieved sustained virologic control and participated in a neurodevelopmental follow-up study (P1104s) between ages 5 and 11 years. We measured 20 inflammatory biomarkers using ELISA or chemiluminescence at onset of sustained virologic control (Tc) and at P1104s entry (Te). The 213 participants had median ages of 1.2, 1.9, and 7 years at antiretroviral initiation, Tc, and Te, respectively, with 138 on protease inhibitor-based and 74 on NNRTI-based regimens at Tc. Eighteen markers decreased and two increased from Tc to Te (Te-Tc). Biomarker subsets, particularly cytokines, the chemokine IP-10, and adhesion molecules sICAM-1 and sVCAM-1, correlated at Tc, Te, and Te-Tc. At Tc, higher biomarker levels were associated with younger age, female sex, HIV plasma RNA at least 750 000 copies/ml, lower nadir CD4 + %, lower nadir weight z scores, and NNRTI-based treatment. Greater Te-Tc biomarker declines were associated with younger age, male sex, higher Tc biomarker levels, lower nadir CD4 + %, and NNRTI-based treatment. Duration of controlled viremia and nadir height z scores showed mixed associations. Biomarker expression showed substantial coordination. Most markers decreased after virologic control. Demographic and clinical variables associated with biomarker patterns were identified. Mechanistic studies of these biomarker patterns are needed to inform interventions to control inflammation.

Balancing Statistical Power and Risk in HIV Cure Clinical Trial Design.

BackgroundAnalytical treatment interruptions (ATI) are pauses of antiretroviral therapy (ART) in the context of human immunodeficiency virus (HIV) cure trials. They are the gold standard in determining if interventions being tested can achieve sustained virological control in the absence of ART. However, withholding ART comes with risks and discomforts to trial participant. We used mathematical models to explore how ATI study design can be improved to maximize statistical power, while minimizing risks to participants.MethodsUsing previously observed dynamics of time to viral rebound (TVR) post-ATI, we modelled estimates for optimal sample size, frequency, and ATI duration required to detect a significant difference in the TVR between control and intervention groups. Groups were compared using a log-rank test, and analytical and stochastic techniques.ResultsIn placebo-controlled TVR studies, 120 participants are required in each arm to detect 30% difference in frequency of viral reactivation at 80% power. There was little statistical advantage to measuring viral load more frequently than weekly, or interrupting ART beyond 5 weeks in a TVR study.ConclusionsCurrent TVR HIV cure studies are underpowered to detect statistically significant changes in frequency of viral reactivation. Alternate study designs can improve the statistical power of ATI trials.

Impact of HIV impact on outcomes of deep-brain stimulation of the subthalamic nucleus for Parkinson's disease.

Middle-aged persons living with HIV (PLHIV) have a heightened risk of more concomitant age-related comorbidities that are acknowledged as signs of poorer prognosis after deep-brain stimulation of the subthalamic nucleus (STN-DBS) at younger-than-expected ages. To assess the beneficial and adverse effects of STN-DBS in PLHIV with Parkinson's disease (PD). We retrospectively included nine PLHIV with PD who had sustained virological control. Patients were followed up for 7±4years. Patients' mean ages at PD onset and STN-DBS were 45±15 and 53±16years, respectively. At STN-DBS, mean HIV infection and PD durations were 15±12 and 8±4years, respectively. STN-DBS significantly improved 1-year Unified Parkinson's Disease Rating Scale (UPDRS)-III scores (71%), daily off-time (63%), motor fluctuations (75%) and daily levodopa-equivalent dose (68%); mean 5-year UPDRS-III score and motor fluctuation improvements remained ~45%. Impulse control disorders (affecting 6/9 patients) fully resolved after STN-DBS. Postoperative course was uneventful. No serious adverse events occurred during follow-up. Our findings indicate that STN-DBS is a safe and effective treatment for PLHIV with PD.

Switching to a Dual-Drug Regimen in HIV-Infected Patients Could Be Associated With Macrophage Activation?

Objectives: The aim of this study was to evaluate the effect on immune activation of switching from a triple-drug to a dual-drug regimen in HIV-1 infected patients on successful combination antiretroviral treatment (cART). Immunadapt is a prospective study evaluating the impact of cART simplification on immune activation.Methods: We prospectively collected blood samples in HIV-1 infected patients on stable and successful cART switching from triple to dual regimens as a simplifying strategy. We compared immune activation markers: high sensitivity CRP, IL-1, IL-6, IL-8, IP-10, MCP-1, TNF-alpha, soluble CD14 (sCD14), soluble CD163 (sCD163), lipopolysaccharide binding protein, and D-dimer before cART change and at least 6 months after the switch. Patients were stratified according to low or high risk factors of immune activation (low CD4 nadir, previous AIDS-defining condition or very-low-level viremia during follow-up).Results: From April 2019 to May 2020, 20 subjects were included (mean age 57 years, 25 years since HIV infection, CD4 666 cells/mm3, CD8 766 cells/mm3, CD4/CD8 0.94, CD4 nadir 326 cells/mm3, 15% with AIDS, 18 years on cART, 6 cART regimens received, current cART duration: 56 months). Fourteen patients were prescribed Dolutegravir + Rilpivirine and six received Dolutegravir + Lamivudine. After 6.9 months, a significant sCD163 increase (+ 25.5% vs. + 0.5%, p = 0.02) was observed in subjects with high risk factors, despite maintaining a viral load <50 cp/ml.Conclusion: cART simplification in favor of dual therapy is associated with macrophage activation in patients at risk of immune activation despite sustained virological control. Risk factors should thus be considered before generalizing such strategies.

Initiating Antiretroviral Treatment Early in Infancy Has Long-term Benefits on the Human Immunodeficiency Virus Reservoir in Late Childhood and Adolescence.

Early combined antiretroviral therapy (cART) limits the total HIV-DNA load in children. However, data on its impact in older children and adolescents remain scarce. This study compares HIV reservoirs in children (5-12 years) and adolescents (13-17 years) who started cART <6 months (early [E-] group) or >2 years (late [L-] group). The ANRS-EP59-CLEAC study prospectively enrolled 76 patients perinatally infected with HIV-1 who reached HIV-RNA <400 copies/mL <24 months after cART initiation, regardless of subsequent viral suppression (E-group: 27 children, 9 adolescents; L-group: 19 children, 21 adolescents). Total and integrated HIV-DNA were quantified in blood and in CD4+ T-cell subsets. A substudy assessed HIV reservoir inducibility after ex vivo peripheral blood mononuclear cell (PBMC) stimulation. Total HIV-DNA levels were lower in early- versus late-treated patients (children: 2.14 vs 2.87 log copies/million PBMCs; adolescents: 2.25 vs 2.74 log; P < .0001 for both). Low reservoir was independently associated with treatment precocity, protective HLA, and low cumulative viremia since cART initiation. The 60 participants with undetectable integrated HIV-DNA started cART earlier than other patients (4 vs 54 months; P = .03). In those with sustained virological control, transitional and effector memory CD4+ T cells were less infected in the E-group than in the L-group (P = .03 and .02, respectively). Viral inducibility of reservoir cells after normalization to HIV-DNA levels was similar between groups. Early cART results in a smaller blood HIV reservoir until adolescence, but all tested participants had an inducible reservoir. This deserves cautious consideration for HIV remission strategies.

Association of intestinal and systemic inflammatory biomarkers with immune reconstitution in HIV+ patients on ART

BackgroundHIV infection is characterized by CD4+ T-cells depletion related to gut damage, microbial translocation, immune activation and intestinal and systemic low-grade inflammation. With the use of antiretroviral treatment, these alterations in HIV+ patients reach similar levels to HIV- controls. However, almost 20% patients have deficient immune reconstitution of CD4+ T-cells, which make them more susceptible to develop non-AIDS and AIDS comorbidities.MethodsHIV+ patients on ART, with sustained virologic control were grouped according to their immune reconstitution as: immunological responders (n = 18) and immunological non-responders (n = 18); also, HIV- controls were enrolled (n = 14). CD4+ and CD8+ T-cell activation (HLA-DR+ and CD38+ single and co-expression) were measured by flow cytometry. Serum levels of sCD14, sCD163, lipopolysaccharide, I-FABP, sST2, as well as fecal levels of calprotectin, lactoferrin and secretory IgA were evaluated by ELISA. Levels of C-reactive protein were determined by a high sensibility singleplex bead-based immunoassay. Serum and fecal concentrations of proinflammatory cytokines were quantified by multiplex bead-based immunoassay.ResultsHLA-DR+ and CD38+ co-expression, as well as median fluorescence intensity in CD4+ and CD8+ T-cells subpopulations was greater in immunological non-responders group, after normalization and fold change calculation. Similarly, this group presented higher levels of sCD14, C-reactive protein, as well as fecal calprotectin and lactoferrin. Furthermore, both HIV+ groups showed elevated levels of proinflammatory cytokines in stool.ConclusionsOur data suggests that despite the virologic control, HIV+ patients under treatment with deficient immune reconstitution showed elevation of both innate and T-cells immune activation, as well as intestinal and systemic inflammation. However, some patients with CD4+ T-cells count above 350 cells/μL also presented these alterations. Future studies are necessary to evaluate the dynamics of multiple systemic and intestinal biomarkers in diverse types of HIV+ patients, as such as their clinical impact.

No HIV-1 molecular evolution on long-term antiretroviral therapy initiated during primary HIV-1 infection.

Most studies about HIV-1 molecular evolution have shown the lack of viral evolution on effective antiretroviral therapy (ART), although controversial results have been documented. We therefore aimed to look for evidence of HIV-1 evolution in patients who initiated ART at the time of primary HIV-1 infection (PHI). We included retrospectively 20 patients diagnosed at PHI, treated at the time of acute infection and with subsequent effective long-term suppressive ART (HIV viral load <20 copies/ml during at least 5 years without any blips). Longitudinal blood samples were deep sequenced using Illumina Miseq. Drug-resistance-associated mutations were retained at 2% cutoff and interpreted using the latest Agence Nationale de Recherches sur le Sida et les Hépatites Virales resistance algorithm. Viral evolution was established when temporal structure on maximum-likelihood phylogenetic tree and significant change over time of HIV-1 genetic diversity measured as the average pairwise distance was observed. Emergences or disappearances of drug-resistance-associated mutations were detected in the blood cells during follow-up despite sustained virological control. In all patients, tree topologies showed an absence of segregation between sequences and blood viral populations from all time-points were intermingled. Comparison of the average pairwise distance showed the absence of significant viral diversity at the time of primary infection and afterwards during 5 years of full virological control under ART. Despite a slight variation of minority resistance-associated mutation variants, there was no clear evidence of viral evolution during a prolonged period of time in this population of highly controlled adult patients treated at time of PHI.

Broadly neutralizing antibodies for the treatment and prevention of HIV infection.

Several anti-HIV-1 broadly neutralizing antibodies (bNAbs) with exceptional breadth and potency, and targeting different HIV-1 envelope epitopes have entered clinical trials. bNAbs are being evaluated for their potential as long-acting alternatives to antiretrovirals in HIV-1 prevention and therapy, and for potential role in strategies aiming at long-term viral remission. Here, we discuss recent findings from bNAb clinical studies. bNAbs targeting distinct HIV-1 envelope epitopes have shown, in general, favorable safety profiles, and engineered bNAb variants have demonstrated improved pharmacokinetics. Single bNAb infusions transiently decreased viremia with subsequent selection of escape variants, while a combination of two bNAbs successfully maintained viral suppression in individuals harboring antibody-sensitive viruses after antiretroviral therapy (ART) was discontinued. Studies in animal models suggest that bNAbs can modulate immune responses and potentially interfere with the establishment or composition of the latent reservoir, and ongoing clinical studies aim to assess potential bNAb-mediated effects on HIV-1 persistence and host immune responses. Early clinical studies support additional evaluation of bNAbs. Antibodies may offer advantages over standard ART for HIV-1 prevention and therapy, and as components of immunologic strategies to achieve sustained virologic control. The evaluation of engineered bNAbs with multispecificity, extended half-lives and increased potency, as well as alternative bNAb-delivery systems are being pursued.

Evaluation of an antibody to α4β7 in the control of SIVmac239-nef-stop infection.

Treatment of SIV-infected rhesus macaques with short-term antiretroviral therapy (ART) and partially overlapping infusions of antibody to integrin α4β7 was reported to induce durable posttreatment viral suppression. In an attempt to replicate those observations, we treated macaques infected with the same virus and with the same ART and monoclonal antibody (mAb) regimens (anti-α4β7 versus control mAb). Sequencing demonstrated that the virus used was actually SIVmac239-nef-stop, not wild-type SIVmac239. A positive correlation was found at 2 weeks after infection between the frequency of repair of attenuated Nef-STOP virus to pathogenic Nef-OPEN and plasma SIV RNA levels. Levels of plasma viremia before the first antibody infusion and preinfection levels of α4β7 hi CD4+ T cells, but not treatment with antibody to α4β7 , correlated with levels of viral replication upon discontinuation of all treatments. Follow-up plasma viremia, peripheral blood CD4+ T cell counts, and lymph node and rectal tissue viral load were not significantly different between anti-α4β7 and control mAb groups.

An antibody is not the antidote

HIV Treatment An HIV therapeutic that would give long-term remission without sustained antiretroviral therapy (ART) is a long-term goal. Byrareddy et al. [ Science 354 , 197 (2016)] reported that treating simian immunodeficiency virus (SIV)–positive macaques with an antibody against integrin α4β7 during and after ART results in sustained virologic control after stopping all treatment. Three studies in this issue question the reproducibility of that result. Di Mascio et al. sequenced the virus used in the 2016 study and found that it was a variant with a stop codon in the nef gene rather than a wild-type virus. Abbink et al. used the same antibody for α4β7 as before but tested control of a more commonly used pathogenic virus. Iwamato et al. used the same nef -stop virus as in the earlier paper but combined the antibody against the integrin with an antibody against the SIV envelope glycoprotein, which also blocks viral binding of the integrin. None of these three new studies found that treating with the antibody had any effect on virologic control after stopping ART treatment. Science , this issue p. [1025][1], p. [1029][2], p. [1033][3] [1]: /lookup/doi/10.1126/science.aav6695 [2]: /lookup/doi/10.1126/science.aaw8562 [3]: /lookup/doi/10.1126/science.aaw7765

Blocking α4β7 integrin binding to SIV does not improve virologic control.

A study in nonhuman primates reported that infusions of an antibody against α4β7 integrin, in combination with antiretroviral therapy, showed consistent, durable control of simian immunodeficiency virus (SIV) in rhesus macaques. The antibody used has pleiotropic effects, so we set out to gain insight into the underlying mechanism by comparing this treatment to treatment with non-neutralizing monoclonal antibodies against the SIV envelope glycoprotein that only block α4β7 binding to SIV Env but have no other host-directed effects. Similar to the initial study, we used an attenuated strain of SIV containing a stop codon in nef. The study used 30 macaques that all began antiretroviral therapy and then were divided into five groups to receive different antibody treatments. Unlike the published report, we found no sustained virologic control by these treatments in vivo.

Lack of therapeutic efficacy of an antibody to α4β7 in SIVmac251-infected rhesus macaques.

Sustained virologic control of human immunodeficiency virus type 1 (HIV-1) infection after discontinuation of antiretroviral therapy (ART) is a major goal of the HIV-1 cure field. A recent study reported that administration of an antibody against α4β7 induced durable virologic control after ART discontinuation in 100% of rhesus macaques infected with an attenuated strain of simian immunodeficiency virus (SIV) containing a stop codon in nef We performed similar studies in 50 rhesus macaques infected with wild-type, pathogenic SIVmac251. In animals that initiated ART during either acute or chronic infection, anti-α4β7 antibody infusion had no detectable effect on the viral reservoir or viral rebound after ART discontinuation. These data demonstrate that anti-α4β7 antibody administration did not provide therapeutic efficacy in the model of pathogenic SIVmac251 infection of rhesus macaques.

New Biomarkers of Chronic Hepatitis B.

Chronic hepatitis B (CHB) infection leads to clinically heterogeneous disease outcomes. Different viral markers are utilized to monitor treatment effects and predict risk of complications in patients with CHB. Hepatitis B core-related antigen (HBcrAg) is a novel serum composite viral protein whose performance has been proven to be superior to that of existing viral markers. It showed good correlation with intrahepatic covalently closed-circular DNA. Its profile differs drastically in patients in different disease phases, and the level declines with antiviral therapies. HBcrAg may be helpful for predicting hepatocellular carcinoma development and hepatitis B virus (HBV) reactivation in immunosuppressed patients. Another emerging measurable serum marker, HBV RNA, exists in the form of pregenomic RNA-containing virions. Its profile differs between patients in different disease phases in a similar manner to that of HBcrAg. HBV RNA is present in serum at lower levels than HBV DNA in treatment-naïve patients by 1–2 logs. In contrast, its level is higher than HBV DNA in patients receiving nucleos(t)ide analogues (NAs). A significant decline in serum RNA was observed in patients receiving novel antiviral therapies, including core protein allosteric modulators and RIG-1/NOD2 agonists. Both HBcrAg and HBV RNA may be helpful for predicting off-therapy sustained virological control in patients who stop long-term NA treatment.

A child with perinatal HIV infection and long-term sustained virological control following antiretroviral treatment cessation

Understanding HIV remission in rare individuals who initiated antiretroviral therapy (ART) soon after infection and then discontinued, may inform HIV cure interventions. Here we describe features of virus and host of a perinatally HIV-1 infected child with long-term sustained virological control. The child received early limited ART in the Children with HIV Early antiRetroviral therapy (CHER) trial. At age 9.5 years, diagnostic tests for HIV are negative and the child has characteristics similar to uninfected children that include a high CD4:CD8 ratio, low T cell activation and low CCR5 expression. Virus persistence (HIV-1 DNA and plasma RNA) is confirmed with sensitive methods, but replication-competent virus is not detected. The child has weak HIV-specific antibody and T cell responses. Furthermore, we determine his HLA and KIR genotypes. This case aids in understanding post-treatment control and may help design of future intervention strategies.

Therapeutic Targeting of HIV Reservoirs: How to Give T Cells a New Direction.

HIV cannot be cured by current antiretroviral therapy (ART) because it persists in a transcriptionally silent form in long-lived CD4+ cells. Leading efforts to develop a functional cure have prioritized latency reversal to expose infected cells to immune surveillance, coupled with enhancement of the natural cytolytic function of immune effectors, or “kick and kill.” The most clinically advanced approach to improving the kill is therapeutic immunization, which aims to augment or re-focus HIV-specific cytolytic T cell responses. However, no vaccine strategy has enabled sustained virological control after ART withdrawal. Novel approaches are needed to overcome the limitations of natural adaptive immune responses, which relate to their specificity, potency, durability, and access to tissue reservoirs. Adoptive T cell therapy to treat HIV infection was first attempted over two decades ago, without success. Since then, progress in the field of cancer immunotherapy, together with recognition of the similarities in tumor microenvironments and HIV reservoirs has reignited interest in the application of T cell therapies to HIV eradication. Advances in engineering of chimeric antigen receptor (CAR)-transduced T cells have led to improved potency, persistence and latterly, resistance to HIV infection. Immune retargeting platforms have incorporated non-neutralizing and broadly neutralizing antibodies to generate Bispecific T cell Engagers (BiTEs) and Dual-Affinity Re-Targeting proteins (DARTs). T cell receptor engineering has enabled the development of the first bispecific Immune-mobilizing monoclonal T Cell receptors Against Viruses (ImmTAV) molecules. Here, we review the potential for these agents to provide a better “kill” and the challenges ahead for clinical development.

CD4+ cell count recovery after combined antiretroviral therapy in the modern combined antiretroviral therapy era.

To assess CD4 recovery after combined antiretroviral therapy (cART) initiation with sustained virologic control. Cohort study based on the French Hospital Database on HIV (FHDH-ANRS CO4). We selected naive HIV-1-infected individuals initiating cART between 2006 and 2014 with CD4 cell counts less than 500 cells/μl who achieved virologic control, defined as two consecutive viral loads less than 50 copies/ml. We estimated the cumulative incidence of CD4 recovery at least 500 cells/μl and identified associated factors, considering 'virologic failure,' 'loss to follow-up' and 'death' as competing events. We analyzed 6050 individuals with a median follow-up of 14.2 months since virologic control. The cumulative incidence for CD4 recovery after 6 years of virologic control reached 69.7%. The main factor associated with CD4 recovery was the CD4 count at treatment initiation [subdistribution hazard ratio (sHR) 9.64, 95% confidence interval (95% CI) 8.12-11.43 for CD4 cell counts between 350 and 500 cells/μl compared with CD4 cell counts <100 cells/μl). A higher CD4/CD8 ratio at initiation was also independently associated with a higher probability of CD4 recovery [sHR 1.67; 95% CI 1.34-2.09] for a CD4/CD8 ratio ≥1.00 vs. < 0.30). Higher viral load at initiation was also associated with a higher probability of CD4 recovery, whereas time to viral suppression was not. After 6 years of sustained virologic control, a large majority of the population achieved CD4 recovery. A higher CD4 cell count at initiation was a strong predictor of CD4 recovery and, to a lesser extent, a higher CD4/CD8 ratio at initiation. These results confirm the necessity of early treatment.

Therapeutic vaccination for HIV: hopes and challenges.

This review summarizes the recent landscape of HIV therapeutic vaccine research, emphasizing the results of randomized controlled trials that included analytical treatment interruption (ATI) to assess efficacy. Therapeutic vaccines for HIV are designed to re-educate the host immune response in HIV-infected individuals to better control viral replication in the absence of antiretroviral therapy. No therapeutic vaccine has yet to induce long-term HIV remission following ATI in a randomized controlled trial. This is likely because the vaccines have not elicited a broad enough immune response to suppress the diverse escape variants that emerge during viral rebound, and have not been used with effective agents to reduce the HIV reservoir. Recent studies in nonhuman primates using combination approaches are showing significant successes, with several candidates eliciting significant antiviral activity following ATI. Future studies pairing these vaccines with effective reservoir reduction hold great promise. Therapeutic vaccines aim to modulate the immune system of HIV-infected individuals to elicit sustained virologic control in the absence of antiretroviral therapy. Therapeutic vaccines that elicit broad immune responses have recently shown promise in randomized controlled trials and nonhuman primate studies.