Viral Load Rebound Research Articles

Long-term control of HIV replication with dolutegravir and pegylated interferon alpha-2a in an HIV-infected patient with sixtuple-class resistance

With contemporary antiretroviral therapy (ART), the risk of virological failures leading to multiclass resistance has dramatically diminished. However, there are still patients from the pre highly active ART era with multiple-class resistance for whom designing salvage regimens can be very challenging. We report the use of a novel combination – dolutegravir (DTG) and peg-interferon alfa-2a – in a patient with sixtuple-class resistance. The patient is a 56-year-old man, diagnosed with HIV infection in 1992. After diagnosis, he started treatment with azydothimidine monotherapy and subsequently received dual [nucleoside reverse transcriptase inhibitor NRTI] and triple (NRTI + non-NRTI/protease inhibitor)-drug antiretroviral regimens, as part of routine care and through clinical trials such as TORO (enfuvirtide) [1], DUET (darunavir/ritonavir) [2] (randomized to control arm), and raltegravir expanded access. He had been treated with all of the following: dideoxycytidine dideoxyinosine saquinavir, nelfinavir, nevirapine, abacavir, efavirenz, hydroxyurea, lopinavir/ritonavir, amprenavir, enfuvirtide, tipranavir, tenofovir, emtricitabine (FTC), darunavir/ritonavir, etravirine, maraviroc and raltegravir. Unfortunately, he received many of these antiretovirals as functional monotherapy, without other active drugs. He had never achieved sustained virological suppression. In 2010, while receiving tenofovir difumarate (TDF)/FTC and darunavir/ritonavir and maraviroc, he developed oral candidiasis and wasting. At that time, his CD4+ cell count was 28 cells/μl and the HIV-RNA viral load 1 100 000 copies/ml. Drug resistance genotype testing showed the following as described below. Reverse transcriptase (bold: mutations present in historical genotypes, but not in the last available genotype): M41L, K101E, V108I, V118I, Y181C, M184 V, G190A L210W, T215Y, V179F. According to the Stanford University HIV Drug Resistance Database interpretation algorithm these mutations confer high-level resistance to all nucleos(t)ides and non-nucleoside reverse transcriptase inhibitors. Protease: L10F, V32I, I54L, Q58E, G73S, V82L, I84V, L90M, V11I, M36L, L89V. These mutations confer high-level resistance to all protease inhibitors. Fusion inhibitor resistance: V38M V38A. These mutations reduce enfuvirtide susceptibility by more than 10-fold in site-directed mutants and most clinical isolates. HIV tropism test performed in April 2009 (Trofile): dual/mixed R5/X4 tropic virus. CCR5 inhibitors not active. Integrase: E92Q, N155H, N155I. These mutations confer high-level resistance to raltegravir and elvitegravir and low-level resistance to DTG. On April 2011, the patient initiated DTG (50 mg b.i.d.) through a named patient/compassionate use program, high-dose darunavir/ritonavir (1000/100 mg b.i.d.), peg-interferon alfa-2a (180 μg weekly) and stavudine (d4T), TDF/FTC and enfuvirtide at standard doses (Table 1). This initial regimen produced a rapid decrease in viral load, but the patient did not achieve complete suppression. For this reason, enfuvirtide was switched to foscarnet after 1 month. Subsequently, the patient achieved virological suppression and foscarnet was stopped. We performed one attempt to switch peg-interferon alfa-2a for oral valaciclovir, but due to a low-level viral rebound valaciclovir was discontinued and weekly peg-interferon alfa-2a reintroduced. Subsequently, for the past 18 months, the patient has been receiving DTG, high-dose darunavir/ritonavir, maraviroc and weekly peg-interferon alfa-2a. This regimen has maintained consistent virologic suppression. The patient has experienced substantial immunological reconstitution with increasing CD4+ cell counts and complete resolution of oral candidiasis and wasting.Table 1: HIV-RNA and CD4+ evolution.We believe that peg-interferon alfa-2a contributed significantly to the antiviral efficacy of the regimen. It is a proven antiviral with activity against HIV [3]. In our case, one attempt to stop peg-interferon alfa-2a, when the patient was virologically suppressed was followed by a low-level viral load rebound. Interestingly, Azzoni et al.[4] have recently reported that administration of peg-interferon alfa-2a to individuals receiving suppressive ART resulted in a sustained control of viral replication in almost half of the patients who interrupted antiretrovirals. If we consider peg-interferon alfa-2a as an active antiretroviral in the background regimen, then our patient's response is in accordance with the DTG VIKING 3 clinical trial results. In VIKING 3, if the baseline genotype did not harbor the Q148 integrase resistance mutations, and the background regimen had an overall susceptibility score of 1, then the proportion of patients with HIV-RNA less than 50 copies/ml at week 24 was 88% [5]. We maintain unconventionally high-dose darunavir/ritonavir in light of the high-level resistance, thus expecting residual activity. We also maintain maraviroc with the hope that it retains activity against subpopulations of R5 tropic viruses. These observations remain speculative, as we have not attempted to discontinue each of the components of the regimen. Interestingly, we have been able to stop all inactive nucleos(t)ides. In summary, our case provides a proof of concept that, in the context of sixtuple-class resistance, the combination of DTG and peg-interferon alfa-2a is able to achieve long-term virologic control if there are no Q148 integrase drug-resistance mutations. This combination merits further study in exceptionally difficult-to-treat cases such as ours. Acknowledgements Conflicts of interest There are no conflicts of interest.

Emergence of G186D Mutation in the Presence of R292K Mutation in an Immunocompromised Child Infected with Influenza A/H3N2 Virus, Treated with Oseltamivir

An immunocompromised child with influenza A/H3N2 virus infection, treated with oseltamivir from day 1, had nasal swabs taken on days 1, 4, 7, and 10 of the illness. Pyrosequencing showed increasing proportions of viruses with R292K (neuraminidase gene) and G186D (hemagglutinin gene) mutations, resulting in a viral load rebound by day 10.

The importance of HIV RNA detection below 50 copies per mL in HIV-positive patients on antiretroviral therapy: an observational study

BackgroundSuppression of plasma HIV viral load to less than 50 copies per mL is associated with durable clinical and immunological benefits and is the recommended goal of antiretroviral therapy (ART). Currently available viral load assays can detect HIV RNA below this threshold but the importance of low-level detection is unclear. We aimed to determine whether HIV RNA detection below 50 copies per mL is associated with an increased risk of virological rebound in ART-treated patients. Methods1247 HIV-positive patients on ART with viral load less than 50 copies per mL at a single arbitrary timepoint as measured by RealTime PCR (Abbott, Maidenhead, UK) were stratified by the clinically unreported viral load into three groups: 40–49 copies per mL (RNA40–49), less than 40 copies per mL but not quantifiable (RNA+), and not detected (RNA−). Virological outcomes over the following 12 months were analysed. Time to viral load rebound according to baseline viral load category was assessed and the factors associated with rebound were identified in a Cox proportional hazards model incorporating baseline viral load, clinical and demographic data, and adherence levels. FindingsOver 12 months of follow-up the proportion of patients experiencing viral load rebound of more than 50 copies per ml in the RNA40–49, RNA+, and RNA–groups were 34·2% (82/240), 11·3% (57/507), and 4% (20/500), respectively. For viral rebound of more than 400 copies per mL the proportions were 13% (31/240), 3·8% (19/507), and 1·2% (6/500), respectively. After multivariate adjustment, the hazard ratio for rebound of more than 400 copies per mL was 6·91 (95% CI 2·90–16·47, p<0·0001) for baseline RNA40–49 and 2·88 (1·24–6·69, p<0·0001) for baseline RNA+. Baseline viral load category predicted rebound independently of adherence levels. InterpretationIn ART-treated HIV-positive patients, detection of viral load between 40 and 49 copies per mL and less than 40 copies per mL (as measured by RealTime PCR) is associated with an increased risk of virological failure. The currently recommended goal of ART of 50 copies per mL might be suboptimal and might need to be revised to a lower cut-off. FundingRoyal Free Hospital NHS Trust, European AIDS Treatment Network.

Gender Differences in Clinical Outcomes among HIV-Positive Individuals on Antiretroviral Therapy in Canada: A Multisite Cohort Study

BackgroundCohort data examining differences by gender in clinical responses to combination antiretroviral therapy (ART) remain inconsistent and have yet to be explored in a multi-province Canadian setting. This study investigates gender differences by injection drug use (IDU) history in virologic responses to ART and mortality.MethodsData from the Canadian Observational Cohort (CANOC) collaboration, a multisite cohort study of HIV-positive individuals initiating ART after January 1, 2000, were included. This analysis was restricted to participants with a follow-up HIV-RNA plasma viral load measure and known IDU history. Weibull hazard regression evaluated time to virologic suppression (2 consecutive measures <50 copies/mL), rebound (>1000 copies/mL after suppression), and all-cause mortality. Sensitivity analyses explored the impact of presumed ART use in pregnancy on virologic outcomes.ResultsAt baseline, women (1120 of 5442 participants) were younger (median 36 vs. 41 years) and more frequently reported IDU history (43.5% vs. 28.8%) (both p<0.001). Irrespective of IDU history, in adjusted multivariable analyses women were significantly less likely to virologically suppress after ART initiation and were at increased risk of viral load rebound. In adjusted time to death analysis, no differences by gender were noted. After adjusting for presumed ART use in pregnancy, observed gender differences in time to virologic suppression for non-IDU, and time to virologic rebound for IDU, became insignificant.ConclusionsHIV-positive women in CANOC are at heightened risk for poor clinical outcomes. Further understanding of the intersections between gender and other factors augmenting risk is needed to maximize the benefits of ART.

In Vivo Blockade of the Programmed Cell Death-1 Pathway Using Soluble Recombinant PD-1-Fc Enhances CD4+ and CD8+ T Cell Responses but Has Limited Clinical Benefit

The programmed cell death-1 (PD-1)/programmed cell death ligand-1 pathway has been shown to limit cell-mediated effector functions during chronic viral infections impeding clearance of pathogens. As a strategy to reverse this exhaustion and increase T cell polyfunctionality, PD-1 ligands were blocked in vivo using a recombinant macaque PD-1 fused to a macaque Ig-Fc (rPD-1-Fc) in SIVmac239-infected rhesus macaques during the early chronic phase of infection, either alone or in combination with antiretroviral therapy. In vitro blockade showed improvement of Ag-specific CD4(+) and CD8(+) T cells from monkeys chronically infected with SIV. Of note, a prolonged 5-d blockade in culture was beneficial for both gag-specific CD4(+) and CD8(+) T cells based on proliferation and dual cytokine production. Although the in vivo administration of rPD-1-Fc induced enhanced SIV-specific CD4 and CD8 T cell proliferation both in the blood and gut, it failed to alter plasma viremia. However, rPD-1-Fc administration in the context of antiretroviral therapy interruption induced a significant delay of viral load rebound. In addition, rPD-1-Fc administration in MamuA*001(+) monkeys led to both an increase in the frequencies and Ki67 expression of GagCM9(+) CD8(+) T cells in the blood and rectal mucosa and polyfunctionality of GagCM9(+) CD8(+) T cells in blood. In conclusion, however, our data suggest that PD-1/programmed cell death ligand-1 blockade using soluble rPD-1-Fc instead of anti-PD-1 mAb, although effective in rescuing the effector function of SIV-specific CD4(+) and CD8(+) T cells during the early chronic phase of infection, has limited clinical benefit.

Backward bifurcation in a mathematical model for HIV infection in vivo with anti-retroviral treatment

Anti-retroviral treatments (ART) such as HAART have been used to control the replication of HIV virus in HIV-positive patients. In this paper, we study an in-host model of HIV infection with ART and carry out mathematical analysis of the global dynamics and bifurcations of the model in different parameter regimes. Among our discoveries is a parameter region for which backward bifurcation can occur. Biologically, the catastrophic behaviors associated with backward bifurcations may explain the sudden rebound of HIV viral load when ART is stopped, and possibly provide an explanation for the viral blips during ART suppression of HIV.

Haemopoietic stem-cell transplantation and long-term immune suppression in a patient with HIV infection receiving intensified early antiretroviral treatment

BackgroundEarly antiretroviral treatment (ART), haemopoietic stem-cell transplantation (HSCT), and long-term immune suppression are promising strategies for control of HIV infection, which could potentially allow ART interruption. Here we discuss a patient with HIV infection who received early intensified ART and underwent HSCT for aplastic anaemia. Case presentationA 12-year-old boy with aplastic anaemia acquired HIV infection through platelet transfusion while being treated with oral cyclosporine (10 mg/kg per day), prednisone (1 mg/kg per day), and subcutaneous filgrastim (5 μg/kg per day). Diagnosis was confirmed with a detectable plasma viral load of 508 000 copies per mL. Early ART was started 30 days after HIV infection (zidovudine/lamivudine, lopinavir/ritonavir, intensified with enfuvirtide). Because of HIV infection, physicians decided to postpone HSCT. Cyclosporine was substituted by mycophenolate mofetil (18 mg/kg per day) after 70 days of HIV infection. Plasma viral load was undetectable (<40 HIV RNA copies per mL) after 4 months of ART. After 250 days of HIV infection, the patient underwent HSCT from a sibling donor with an identical HLA genotype (A*02:01:01:01/02:01:01:01; B*41:01/27:05:02; C*02:02:02/17:01:01:01). Both were heterozygous for the CCR5Δ32 mutation. The conditioning regimen consisted of antithymocyte globulin (5 mg/kg per day) and cyclophosphamide (50 mg/kg per day) on day −5 to day −2, and intravenous cyclosporine (5 mg/kg per day) on day −1. Leucocyte engraftment was confirmed (day 9) and mycophenolate was continued for 2 years. Plasma viral load remained undetectable for 3 years. During this period, the patient did not show symptoms of aplastic anaemia, graft-versus-host disease, opportunistic infections, or serious side-effects linked to immunosuppression. At this point (aged 15 years), the patient arrived at our institution, where we started a follow-up protocol after acquiring informed consent from the patient and his parents. The patient had an indeterminate Western blot, negative HIV-ELISA, undetectable plasma viral load, a CD4 count of 766 cells per μL, and a proviral load of 2·88 DNA copies in peripheral blood memory CD4+ T cells (assay detection limit of 2·6 DNA copies). We started a programmed ART interruption protocol. Plasma viral load remained undetectable for 9 days. However, at day 14 the patient had a plasma viral load of 16 566 copies per mL and developed herpes zoster. ART was restarted at day 16 (plasma viral load of 440 307 copies per mL) with a regimen of tenofovir, emtricitabine, and efavirenz. Chimaerism was 89% after 56 months of HSCT. At present (aged 17 years), the patient is well and without symptoms of aplastic anaemia or HIV infection (undetectable plasma viral load and a CD4 count of 990 cells per μL). Consent was acquired from the patient's representatives to publish these data. InterpretationThis case emphasises that early and intensified ART, HSCT, and long-term immune suppression do not assure HIV control after ART discontinuation. Our patient was unable to control HIV infection without ART even though both he and the donor had the HLA B*27:05 allele and were heterozygous for the CCR5Δ32 mutation. HIV plasma viral load rebound could have been caused by remaining infected cells of the recipient because 100% chimerism was not achieved. Other factors to be considered are the absence of graft-versus-host disease, as well as conditioning and maintenance regimens and their potential effects on latently infected cells when compared with recently reported cases. FundingThis work was supported by grants from the Mexican Government (Comisión de Equidad y Género de la Honorable Cámara de Diputados de la LXI Legislatura de México), and Fundación México Vivo (http://www.mexicovivo.org/).

Antiviral therapy delays esophageal variceal bleeding in hepatitis B virus-related cirrhosis

To investigate the effect of antiviral therapy with nucleoside analogs in hepatitis B virus (HBV)-related cirrhosis and esophageal varices. Eligible patients with HBV-related cirrhosis and esophageal varices who consulted two tertiary hospitals in Beijing, China, the Chinese Second Artillery General Hospital and Chinese PLA General Hospital, were enrolled in the study from January 2005 to December 2009. Of 117 patients, 79 received treatment with different nucleoside analogs and 38 served as controls. Bleeding rate, change in variceal grade and non-bleeding duration were analyzed. Multivariate Cox proportional hazard regression was used to identify factors related to esophageal variceal bleeding. The bleeding rate was decreased in the antiviral group compared to the control group (29.1% vs 65.8%, P < 0.001). Antiviral therapy was an independent factor related to esophageal bleeding in multivariate analysis (HR = 11.3, P < 0.001). The mean increase in variceal grade per year was lower in the antiviral group (1.0 ± 1.3 vs 1.7 ± 1.2, P = 0.003). Non-bleeding duration in the antiviral group was prolonged in the Kaplan-Meier model. Viral load rebound was observed in 3 cases in the lamivudine group and in 1 case in the adefovir group, all of whom experienced bleeding. Entecavir and adefovir resulted in lower bleeding rates (17.2% and 28.6%, respectively) than the control (P < 0.001 and P = 0.006, respectively), whereas lamivudine (53.3%) did not (P = 0.531). Antiviral therapy delays the progression of esophageal varices and reduces bleeding risk in HBV-related cirrhosis, however, high-resistance agents tend to be ineffective for long-term treatment.

Influence of Episodes of Intermittent Viremia (“Blips”) on Immune Responses and Viral Load Rebound in Successfully Treated HIV-Infected Patients

Presenting episodes of intermittent viremia (EIV) under combination antiretroviral therapy (cART) is frequent, but there exists some controversy about their consequences. They have been described as inducing changes in immune responses potentially associated with a better control of HIV infection. Conversely, it has been suggested that EIV increases the risk of virological failure. A retrospective analysis of a prospective, randomized double-blinded placebo-controlled study was performed. Twenty-six successfully treated HIV-infected adults were randomized to receive an immunization schedule or placebo, and after 1 year of follow-up cART was discontinued. The influence of EIV on T cell subsets, HIV-1-specific T cell immune responses, and viral load rebound, and the risk of developing genotypic mutations were evaluated, taking into account the immunization received. Patients with EIV above 200 copies/ml under cART had a lower proportion of CD4(+) and CD4(+)CD45RA(+)RO(-) T cells, a higher proportion of CD8(+) and CD4(+)CD38(+)HLADR(+) T cells, and higher HIV-specific CD8(+) T cell responses compared to persistently undetectable patients. After cART interruption, patients with EIV presented a significantly higher viral rebound (p=0.007), associated with greater increases in HIV-specific lymphoproliferative responses and T cell populations with activation markers. When patients with EIV between 20 and 200 copies/ml were included, most of the differences disappeared. Patients who present EIV above 200 copies/ml showed a lower CD4(+) T cell count and higher activation markers under cART. After treatment interruption, they showed greater specific immune responses against HIV, which did not prevent a higher virological rebound. EIV between 20 and 200 copies/ml did not have this deleterious effect.

Viral load rebound in presumed elite controllers: a small case series of the potential use of non‐prescribed HAART in African patients

IntroductionHIV elite controllers are rare with an incidence of &lt;1/300 [1]. We report 4 cases of presumed elite control with subsequent viral load rebound possibly due to non‐prescribed HAART. Case 1: A 37‐year‐old African woman trafficked to the UK was diagnosed HIV‐positive with viral load (VL) &lt;40 copies/mL and CD4 count of 436 cells/cmm. She denied prior diagnosis and was presumed an elite controller until a rise in VL to 26,5205 copies/mL 6 months later (Table 1). Time from diagnosis CD4 (cells/cmm) Viral load (copies/mL) 0 436 (26%) &lt;40 1 month 424 (18%) &lt;40 3 months N/A &lt;40 6 months 387 (29%) 265,205 6 months 264 (18%) 338,291 A resistance test reported HIV‐1 subtype C with a minor protease inhibitor mutation (A71T). It was subsequently disclosed she was given unidentified tablets by traffickers. Case 2: A 31‐year‐old African woman presented 37 weeks pregnant and was diagnosed HIV‐positive with VL 147 copies/mL and CD4 count of 1065 cells/cmm. She denied prior diagnosis, however stated an African doctor visited her ex‐partner's home and supplied tablets identified as lopinavir/ritonavir and zidovudine/lamivudine. Clinics in this area were contacted but had no record of this patient. There was a rise in VL with a resistance test reporting HIV‐1 subtype C/D with no mutations. Case 3: A 53‐year‐old African woman presented 6 weeks after a sexual assault in her home country and was diagnosed HIV‐positive with VL&lt;40 copies/mL and CD4 count of 609 cells/cmm. She denied prior diagnosis but stated her employers gave her unidentified tablets after the assault. Over 3 months VL increased to 390,751 copies/mL (Table 2). Time from diagnosis CD4 (cells/cmm) Viral load (copies/mL) 0 609 (30%) &lt;40 1 month 763 (29%) &lt;40 2 months N/A 417 4 months 616 (19%) 390,751 6 months 237 (18%) 67,833 A resistance test reported HIV‐1 subtype A with no mutations. Case 4: A 42‐year‐old African man was diagnosed HIV positive with VL 269 copies/mL and CD4 count of 562 cells/cmm. A resistance test reported HIV‐1 subtype B with minor PI and NRTI mutations (L10V and V118L respectively). HIV parameters remained stable until 20 months later with an increase in VL to 1,463,132 copies/mL (Table 3). Time from diagnosis CD4 (cells/cmm) Viral load (copies/mL) 0 562 (33%) 269 3 months 454 (37%) 810 6 months 456 (29%) 1110 9 months 492 (31%) 1013 14 months 473 (27%) 199 20 months 279 (13%) 1,463,132 20 months 299 (12%) 1,070,823 A resistance test excluded super‐infection reporting a similar sequence and no new mutations. Co‐existing pathology was also excluded. He subsequently disclosed taking medication supplied by his family but denied this was HAART.ConclusionThe viral load rebound seen in these cases may be due to a viral or immune mediated phenomenon; however, the possibility of non‐prescribed HAART has to be considered. Home test kits for HIV are widely available and there are reports of counterfeit HAART in the developing world [2]. The HIV community has to be vigilant in reporting cases of this nature which create many anxieties regarding toxicity and resistance.

Plasma HIV Viral Rebound following Protocol-Indicated Cessation of ART Commenced in Primary and Chronic HIV Infection

ObjectivesThe magnitude of HIV viral rebound following ART cessation has consequences for clinical outcome and onward transmission. We compared plasma viral load (pVL) rebound after stopping ART initiated in primary (PHI) and chronic HIV infection (CHI).DesignTwo populations with protocol-indicated ART cessation from SPARTAC (PHI, n = 182) and SMART (CHI, n = 1450) trials.MethodsTime for pVL to reach pre-ART levels after stopping ART was assessed in PHI using survival analysis. Differences in pVL between PHI and CHI populations 4 weeks after stopping ART were examined using linear and logistic regression. Differences in pVL slopes up to 48 weeks were examined using linear mixed models and viral burden was estimated through a time-averaged area-under-pVL curve. CHI participants were categorised by nadir CD4 at ART stop.ResultsOf 171 PHI participants, 71 (41.5%) rebounded to pre-ART pVL levels, at a median of 50 (95% CI 48–51) weeks after stopping ART. Four weeks after stopping treatment, although the proportion with pVL≥400 copies/ml was similar (78% PHI versus 79% CHI), levels were 0.45 (95% CI 0.26–0.64) log10 copies/ml lower for PHI versus CHI, and remained lower up to 48 weeks. Lower CD4 nadir in CHI was associated with higher pVL after ART stop. Rebound for CHI participants with CD4 nadir >500 cells/mm3 was comparable to that experienced by PHI participants.ConclusionsStopping ART initiated in PHI and CHI was associated with viral rebound to levels conferring increased transmission risk, although the level of rebound was significantly lower and sustained in PHI compared to CHI.

Kinetics of Nevirapine and Its Impact on HIV-1 RNA Levels in Maternal Plasma and Breast Milk Over Time After Perinatal Single-Dose Nevirapine

To determine kinetics after single-dose nevirapine and the impact on HIV RNA [viral load (VL)] in maternal plasma and breast milk (BM). Cohort of 120 HIV-1-infected pregnant Ugandan women received perinatal single-dose nevirapine alone and followed up with their infants through 24 weeks postdelivery. We assessed the relationship of nevirapine concentration (tandem mass spectroscopy) and HIV-1 VL (Roche AMPLICOR HIV-1 Kit, version 1.5) in maternal plasma and BM over time. At week 1 postpartum, NVP (≥10 ng/mL) was detected in all 53 plasma and 47 of 51 (92.2%) BM samples with median (interquartile ranges) of, respectively, 171 (78-214) ng/mL and 112 (64-158) ng/mL, P = 0.075, which decreased subsequently with traces persisting through week 4 in plasma. Plasma and BM VL dropped by week 1 and were highly correlated at delivery (R = 0.71, P < 0.001) and week 1 (R = 0.69, P < 0.001) but not thereafter. At week 1, VL correlated inversely with NVP concentration in plasma (R = 0.39, P = 0.004) and BM (R = 0.48, P = 0.013). There was a VL rebound in both compartments, which peaked at week 4 to levels greater than those at week 1 [significantly in plasma (P < 0.001) but not in BM] and remained stable thereafter. Median VL was consistently greater (11- to 50-fold) in plasma than BM at all time points (all P < 0.001). After single-dose nevirapine, NVP concentration was comparably high through week 1, accompanied by suppression of plasma and BM VL. A longer "tail" (>1 week) of potent postnatal antiretroviral drugs is warranted to minimize the observed VL rebound and potential for NVP resistance as a result of persistent NVP traces.

A Highly Intensified ART Regimen Induces Long-Term Viral Suppression and Restriction of the Viral Reservoir in a Simian AIDS Model

Stably suppressed viremia during ART is essential for establishing reliable simian models for HIV/AIDS. We tested the efficacy of a multidrug ART (highly intensified ART) in a wide range of viremic conditions (103–107 viral RNA copies/mL) in SIVmac251-infected rhesus macaques, and its impact on the viral reservoir. Eleven macaques in the pre-AIDS stage of the disease were treated with a multidrug combination (highly intensified ART) consisting of two nucleosidic/nucleotidic reverse transcriptase inhibitors (emtricitabine and tenofovir), an integrase inhibitor (raltegravir), a protease inhibitor (ritonavir-boosted darunavir) and the CCR5 blocker maraviroc. All animals stably displayed viral loads below the limit of detection of the assay (i.e. <40 RNA copies/mL) after starting highly intensified ART. By increasing the sensitivity of the assay to 3 RNA copies/mL, viral load was still below the limit of detection in all subjects tested. Importantly, viral DNA resulted below the assay detection limit (<2 copies of DNA/5*105 cells) in PBMCs and rectal biopsies of all animals at the end of the follow-up, and in lymph node biopsies from the majority of the study subjects. Moreover, highly intensified ART decreased central/transitional memory, effector memory and activated (HLA-DR+) effector memory CD4+ T-cells in vivo, in line with the role of these subsets as the main cell subpopulations harbouring the virus. Finally, treatment with highly intensified ART at viral load rebound following suspension of a previous anti-reservoir therapy eventually improved the spontaneous containment of viral load following suspension of the second therapeutic cycle, thus leading to a persistent suppression of viremia in the absence of ART. In conclusion, we show, for the first time, complete suppression of viral load by highly intensified ART and a likely associated restriction of the viral reservoir in the macaque AIDS model, making it a useful platform for testing potential cures for AIDS.

Immune and Viral Correlates of “Secondary Viral Control” after Treatment Interruption in Chronically HIV-1 Infected Patients

Upon interruption of antiretroviral therapy, HIV-infected patients usually show viral load rebound to pre-treatment levels. Four patients, hereafter referred to as secondary controllers (SC), were identified who initiated therapy during chronic infection and, after stopping treatment, could control virus replication at undetectable levels for more than six months. In the present study we set out to unravel possible viral and immune parameters or mechanisms of this phenomenon by comparing secondary controllers with elite controllers and non-controllers, including patients under HAART. As candidate correlates of protection, virus growth kinetics, levels of intracellular viral markers, several aspects of HIV-specific CD4+ and CD8+ T cell function and HIV neutralizing antibodies were investigated. As expected all intracellular viral markers were lower in aviremic as compared to viremic subjects, but in addition both elite and secondary controllers had lower levels of viral unspliced RNA in PBMC as compared to patients on HAART. Ex vivo cultivation of the virus from CD4+ T cells of SC consistently failed in one patient and showed delayed kinetics in the three others. Formal in vitro replication studies of these three viruses showed low to absent growth in two cases and a virus with normal fitness in the third case. T cell responses toward HIV peptides, evaluated in IFN-γ ELISPOT, revealed no significant differences in breadth, magnitude or avidity between SC and all other patient groups. Neither was there a difference in polyfunctionality of CD4+ or CD8+ T cells, as evaluated with intracellular cytokine staining. However, secondary and elite controllers showed higher proliferative responses to Gag and Pol peptides. SC also showed the highest level of autologous neutralizing antibodies. These data suggest that higher T cell proliferative responses and lower replication kinetics might be instrumental in secondary viral control in the absence of treatment.

Molecular control of HIV - 1 postintegration latency: implications for therapeutic strategies

The current antiretroviral therapy HAART is effective and life-prolonging but does not eradicate HIV-1 from infected patients. A reduction of HIV-1 RNA levels in the plasma in HAART-treated individuals to less than 50 copies/ml is frequently achieved but residual viremia persists as detected by ultrasensitive assays. The sources of this persistent viremia are still not fully understood but could arise from ongoing cycles of residual viral replication and/or from the reactivation of viral expression from latently-infected cells. These latently-infected cells contain stably-integrated, transcriptionally-silent but replication-competent proviruses, thereby representing latent reservoirs of HIV-1. They are a permanent source for virus reactivation and could be responsible for the rebound of plasma viral load observed after HAART interruption. HIV-1 transcriptional repression is crucial to the establishment and maintenance of postintegration latency. Several elements contribute to HIV-1 transcriptional repression including: 1) the site of integration and mechanisms of transcriptional interference, 2) the absence of crucial inducible host transcription factors, 3) the presence of transcriptional repressors, 4) the nucleosomal organization of the HIV-1 promoter, 5) the epigenetic control of the HIV-1 promoter (histone posttranslational modifications, such as acetylation and methylation, and DNA methylation), 6) the sequestration in an inactive form of the cellular positive transcription elongation factor b (P-TEFb), composed of cyclin-dependent kinase 9 (CDK9) and human cyclin T1, 7) the absence of the viral transactivator Tat, which promotes transcription via recruitment to the HIV-1 promoter of P-TEFb, histonemodifying enzymes and ATP-dependent chromatin-remodeling complexes required for nucleosomal disruption and transcriptional processivity. The involvement of these elements in postintegration latency depends on the status of activation and differentiation of the heterogeneous CD4 T cell populations hosting the HIV-1 reservoirs. Further understanding of the epigenetic and nonepigenetic mechanisms regulating HIV-1 latency and reactivation from latency should help devise novel strategies to eliminate latent HIV-1 infection or to restrict the latent pool to a size bearable by the host immune system.

Social and Environmental Predictors of Plasma HIV RNA Rebound Among Injection Drug Users Treated With Antiretroviral Therapy

Evidence is needed to improve HIV treatment outcomes for individuals who use injection drugs (IDU). Although studies have suggested higher rates of plasma viral load (PVL) rebound among IDU on antiretroviral therapy (ART), risk factors for rebound have not been thoroughly investigated. We used data from a long-running community-recruited prospective cohort of IDU in Vancouver, Canada, linked to comprehensive ART and clinical monitoring records. Using proportional hazards methods, we modeled the time to confirmed PVL rebound above 1000 copies per milliliter among IDU on ART with sustained viral suppression, defined as 2 consecutive undetectable PVL measures. Between 1996 and 2009, 277 individuals had sustained viral suppression. Over a median follow-up of 32 months, 125 participants (45.1%) experienced at least 1 episode of virologic failure for an incidence of 12.6 [95% confidence interval (CI): 10.5 to 15.0] per 100 person-years. In a multivariate model, PVL rebound was independently associated with sex-trade involvement [adjusted hazard ratio (AHR) = 1.40, 95% CI: 1.08 to 1.82) and recent incarceration (AHR = 1.83, 95% CI: 1.33 to 2.52). Methadone maintenance therapy (AHR = 0.79, 95% CI: 0.66 to 0.94) was protective. No measure of illicit drug use was predictive. In this setting of free ART, several social and environmental factors predicted higher risks of viral rebound among IDU, including sex-trade involvement and incarceration. These findings should help inform efforts to identify individuals at risk of viral rebound and targeted interventions to treat and retain individuals in effective ART.

Towards a world free from HIV and AIDS?

Approximately 30 years ago, in June 1981, it was reported from theCenter forDiseaseControl andPrevention (CDC) that five, otherwise healthy, homosexual men in California had presented with pneumonia caused by Pneumocystis jiroveci pneumonia, a rare disease seen exclusively in individualswith a severely suppressed immune system. Several reports confirmed the initial observation and lent support to the possibility that a new sexually transmitted, infectious agent was circulating within the gay community in the United States. The clinical condition was named acquired immunodeficiency syndrome (AIDS). Two years later, a research team at the Institut Pasteur under the guidance of Francoise Barre-Sinoussi and Luc Montagnier isolated human immunodeficiency virus (HIV), the causative agent of AIDS, from a lymph node biopsy of a French patient. The isolation and characterization of HIV paved the way for the design of diagnosticmethods to identify the virus in blood andbloodproducts and towards the development of novel antiretroviral treatment (ART) to control HIV replication in infected patients. For their discoveries, Barre-Sinoussi and Montagnier were awarded the Nobel Prize in Physiology and Medicine in 2008.

Can immunotherapy be useful for a « functional cure » of HIV infection?

Highly active antiretroviral therapy (HAART) alone cannot eliminate HIV from the body and even in patients with undetectable viral load, full recovery of the system is not being obtained, with signs of inappropriate immune activation and immuno-senescence. Therapeutic strategies, complementary to HAART, aim at a cure i.e. control HIV in such a way that it no longer produces harm to the system. Anti-latency drugs, anti-inflammatory agents and/or measures to prevent or eliminate concomitant infections may contribute to a functional cure. Immunotherapy represents another possible strategy, which should reverse deficient T cell generation, aberrant differentiation, exhaustion and ineffective HlV-specific T cell responses. Four major pathways are being attempted: 1. Administration of so called common γ-chain cytokines, including inter-leukin (IL)-2, IL-7, IL-15 or IL-21, which are crucial in T cell generation, differentiation and function. Only IL-2 has been formally evaluated in a phase 3 trial: although it increased CD4 T counts, it failed to improve clinical outcome. 2. Blockade of negative regulator receptor-ligand interaction, including CTLA-4, PD-1, TIM-3 has been shown to improve HlV-specific T cell function in vitro, but seemingly discrepant results have been obtained in the SIV macaque model. PD-1 blockade lowered viral load and improved survival, whereas CTLA-4 blockade increased viral load, probably because of activation. 3. Therapeutic immunization with HIV antigens. Older trials with de-enveloped HIV particles (Remune®) failed to improve clinical outcome in HIV-infected subjects. More recent trials, using ALVAC®, a canarypox vaccine, containing HIV antigens-encoding genes, mitigated viral load rebound after HAART interruption in several trials, but had no effect or even increased rebound in other trials, the latter result being probably linked to inappropriate activation. 4. The most recent tendency is to target dendritic cells with either inactivated autologous virus or virus antigen-encoding RNA. Safety and immunogenicity of this strategy has been well established, but clinical results are equivocal as yet. In any case, this approach is amendable to further refinement, with regard to inclusion of RNA encoded patient-adapted viral sequences and co-stimulatory molecules, as well as improved targeting. In conclusion, several HIV immunotherapy strategies are being attempted, with varying success. The basic challenge remains to find a (combined) strategy, successfully activating effective HlV-specific T cell responses, while reducing inappropriate HIV-promoting activation.

Effects of the H2-Receptor Antagonist Famotidine on the Pharmacokinetics of Atazanavir-Ritonavir With or Without Tenofovir in HIV-Infected Patients

Significant pharmacokinetic interactions can result between acid-suppressing agents and some protease inhibitors (PIs) in the management of HIV infection. In healthy subjects, famotidine, an H(2)-receptor antagonist, reduces exposures of atazanavir by 4-28% at doses of 20-40 mg twice daily. This study evaluated the effect of famotidine 20-40 mg twice daily on the pharmacokinetics of atazanavir/ritonavir 300/100 mg once daily with and without tenofovir disoproxil fumarate (TDF) 300 mg in HIV-infected patients (n=40; 87.5% male; mean age 42, range 26-63 years; 55% white). Coadministration of famotidine 40 mg and atazanavir/ritonavir to HIV-infected patients reduced exposures of atazanavir by approximately 20%. This is comparable to reductions seen in HIV-uninfected subjects. Coadministration of famotidine 20 mg had less impact on atazanavir exposures, with no reduction of atazanavir geometric mean plasma concentration at 24 h postdose (C(min)). In the presence of TDF, administration of famotidine 20-40 mg twice daily 2 h after and 10 h before atazanavir/ritonavir reduced exposures of atazanavir by 19-25%. However, all individual atazanavir C(min) values remained at least five-fold above the population mean protein-binding adjusted 90% maximum effect (EC(90)) against wild-type HIV (14 ng/mL). No viral load rebound was observed at end of study. The results confirmed that coadministration of an H(2)-receptor antagonist with atazanavir/ritonavir in HIV-infected patients resulted in similar magnitude of reductions in atazanavir exposures as in healthy subjects. This supports the current dose recommendations for coadministration of an H(2)-receptor antagonist with atazanavir/ritonavir.

A randomized controlled trial of HIV therapeutic vaccination using ALVAC with or without Remune

Therapeutic HIV vaccination during the time of virologic suppression may delay or blunt viral load rebound after interruption of antiretroviral therapy (ART). The use of ALVAC, to enhance cytotoxic T-lymphocyte responses, with Remune, which provides CD4 T-cell help, may induce anti-HIV responses capable of controlling viral replication. CTN173 was a randomized, placebo-controlled double-blind study in which effectively treated HIV-infected individuals (viral load <50 copies/ml for more than 2 years) with CD4 nadir more than 250 cells/μl and current CD4 cell counts more than 500 cells/μl were randomized to receive: ALVAC with Remune, ALVAC alone or matching placebos over 20 weeks. At week 24, participants interrupted ART with intensive clinical, virologic and immunologic monitoring to week 48. Baseline characteristics of the 52 randomized participants were balanced between arms. Forty-eight participants who received all vaccinations interrupted ART at week 24. Median time to viral load more than 50 copies/ml tended to be greater in the two vaccine arms (24.5, 23.0 vs. 13.5 days in the placebo arm, P = 0.097 for combined vaccine groups vs. placebo), but subsequent viral load set-point was not different between groups. Significantly fewer participants in the two vaccine arms restarted ART or met CD4 criteria to do so (P = 0.024). Although ALVAC with or without Remune did not lower the viral load set-point, it tended to delay viral load rebound and was associated with a greater time to meet preset criteria to restart ART. Further investigations of those individuals who derived benefit from vaccination could provide important insights into HIV therapeutic vaccine development.