Years Of Suppressive Antiretroviral Therapy Research Articles

Impaired T-cell proliferation among HAART-treated adults with suboptimal CD4 recovery in an African cohort

BackgroundMost HIV-infected subjects exhibit a progressive rise in CD4 T-cell counts after initiation of highly active antiretroviral therapy (HAART). However, a subset of individuals exhibit very poor CD4 T-cell recovery despite effective control of HIV-RNA viraemia. We evaluated CD4 T-cell proliferation among suboptimal responders and its correlation with CD4 T-cell activation.MethodsThe magnitude of CD4 increase (difference between absolute CD4 counts at baseline and absolute CD4 counts at 4 years of ART) was grouped into 4 quartiles for the 211 patients with sustained HIV-RNA viral suppression. Cases of ‘Suboptimal immune responders’ included patients within the lowest quartile [Median CD4 increase 165 (Range −43-298) cells/μl; n=52] and a comparison group of ‘Optimal immune responders’ was defined as patients within the highest quartile of CD4 increase [Median CD4 increase 528 (Range 417–878) cells/μl; n=52]. Frozen PBMC were thawed and analysed from a convenient sample of 39 suboptimal responders and 48 optimal responders after 4 years of suppressive antiretroviral therapy. T-cell activation was measured by proportions of T-cells expressing surface marker CD38 and HLADR (CD4+CD38+HLA-DR+ and CD8+CD38+HLA-DR+ cells). T-cell proliferation was determined by the extent of carboxyfluorescein diacetate succinimidyl ester (CFSE) dye dilution on culture day 5 of PBMCs in the presence of antigen (SEB, PPD, CMVpp65, GagA and GagD). Samples were analyzed on a FACS Calibur flow cytometer and flow data was analyzed using FlowJo and GraphPad.ResultsOverall, CD4 T-cell proliferation on stimulation with SEB, PPD, CMVpp65, Gag A and Gag D.antigens, was lower among suboptimal than optimal responders; this was significant for SEB (CD4+ p=0.003; CD8+ p=0.048) and PPD antigens (CD8+ p=0.038). Among suboptimal responders, T-cell proliferation decreased with increasing immune activation (Negative correlation; slope = −0.13±−0.11) but not among optimal responders.ConclusionT-cell immune activation and exhaustion were associated with poor proliferation among suboptimal responders to HAART despite sustained viral suppression. We recommend studies to further understand the mechanisms leading to impaired T-cell function among suboptimal responders as well as the potential role of immune modulation in optimizing CD4 count and functional recovery after HAART.

Predictors of Residual Viraemia in Patients on Long-Term Suppressive Antiretroviral Therapy

HIV-1-infected individuals with plasma RNA<50 copies/ml on antiretroviral therapy (ART) may have residual, low-level viraemia detectable by PCR assays that are able to detect a single copy of viral RNA (single-copy assay [SCA]). The clinical predictors of residual viraemia in patients on long-term suppressive ART are not yet fully understood. We evaluated factors associated with residual viraemia in patients on suppressive ART who underwent screening for a raltegravir intensification trial (ACTG A5244). The screened population was HIV-1-infected adults receiving ART for ≥ 12 months with pre-ART HIV-1 RNA>100,000 copies/ml and on-therapy RNA levels below detection limits of commercial assays for ≥ 6 months. Of 103 patients eligible for analysis, the median age was 46 years and the median duration of viral suppression was 4.8 years. 62% had detectable viraemia (>0.2 copies/ml) by SCA (median 0.2 copies/ml, IQR <0.2-1.8). Younger patients had lower HIV-1 RNA levels than older individuals (r=0.27, P=0.005). Patients with virological suppression on ART for 2 years or less had higher residual viraemia than those with suppression for >2 years (median 2.3 versus 0.2 copies/ml; P=0.016). Among HIV-1-infected patients with pre-ART HIV-1 RNA>100,000 copies/ml, residual viraemia was detectable in the majority (62%) despite many years of suppressive ART. Higher level viraemia was associated with older age and <2 years of virological suppression on ART. These findings should help in the selection of candidates for clinical trials of interventions designed to eliminate residual viraemia.

An Increasing Proportion of Monotypic HIV-1 DNA Sequences during Antiretroviral Treatment Suggests Proliferation of HIV-Infected Cells

Understanding how HIV-1 persists during effective antiretroviral therapy (ART) should inform strategies to cure HIV-1 infection. We hypothesize that proliferation of HIV-1-infected cells contributes to persistence of HIV-1 infection during suppressive ART. This predicts that identical or monotypic HIV-1 DNA sequences will increase over time during ART. We analyzed 1,656 env and pol sequences generated following single-genome amplification from the blood and sputum of six individuals during long-term suppressive ART. The median proportion of monotypic sequences increased from 25.0% prior to ART to 43.2% after a median of 9.8 years of suppressive ART. The proportion of monotypic sequences was estimated to increase 3.3% per year (95% confidence interval, 2.3 to 4.4%; P < 0.001). Drug resistance mutations were not more common in the monotypic sequences, arguing against viral replication during times with lower antiretroviral concentrations. Bioinformatic analysis found equivalent genetic distances of monotypic and nonmonotypic sequences from the predicted founder virus sequence, suggesting that the relative increase in monotypic variants over time is not due to selective survival of cells with viruses from the time of acute infection or from just prior to ART initiation. Furthermore, while the total HIV-1 DNA load decreased during ART, the calculated concentration of monotypic sequences was stable in children, despite growth over nearly a decade of observation, consistent with proliferation of infected CD4(+) T cells and slower decay of monotypic sequences. Our findings suggest that proliferation of cells with proviruses is a likely mechanism of HIV-1 DNA persistence, which should be considered when designing strategies to eradicate HIV-1 infection.

Dynamics of HIV tropism under suppressive antiretroviral therapy: implications for tropism testing in subjects with undetectable viraemia

The use of maraviroc as part of a simplification of antiretroviral therapy (ART) is hampered by the difficulty of assessing viral tropism in patients with undetectable viraemia. In this context, information on tropism might be obtained from testing either older stored viraemic sera collected before initiation of ART or current proviral DNA in peripheral blood cells. HIV-1-infected individuals who had initiated ART and had undetectable viraemia for >2 years were identified. V3 genotyping was performed in parallel from plasma HIV-RNA and proviral DNA before starting ART and from proviral DNA while on suppressive ART. Viral tropism was interpreted using geno2pheno (false positive rate = 10%) and an optimized version of position specific scoring matrices (PSSM) with a greater sensitivity to detect X4 variants (PSSM(X4/R5-8)). A total of 78 HIV-1 infected individuals were examined. Mean time under suppressive ART was 3.5 years (interquartile range: 2.3-4.4). The rate of X4 variants in plasma and proviral DNA samples at baseline was 32.8% and 34.0%, respectively. It was 33.9% after >2 years of suppressive ART in DNA samples. Paired RNA/DNA tropism results at baseline could be obtained for 38 patients, with an overall 82% concordance. After >2 years of suppressed plasma viraemia, HIV tropism was re-assessed in proviral DNA; tropism switches were uncommon, especially comparing baseline and most recent DNA longitudinal specimens (12%). HIV tropism switches over time under suppressive ART are rare. There is a relatively good correlation between RNA and DNA tropism estimations using genotypic tests. Thus, HIV-1 tropism might confidently be examined either in older stored viraemic plasma specimens or in current proviral DNA samples.

Short-course raltegravir intensification does not reduce persistent low-level viremia in patients with HIV-1 suppression during receipt of combination antiretroviral therapy.

Combination antiretroviral therapy suppresses but does not eradicate human immunodeficiency virus type 1 (HIV-1) in infected persons, and low-level viremia can be detected despite years of suppressive antiretroviral therapy. Short-course (28-day) intensification of standard antiretroviral combination therapy is a useful approach to determine whether complete rounds of HIV-1 replication in rapidly cycling cells contribute to persistent viremia. We investigated whether intensification with the integrase inhibitor raltegravir decreases plasma HIV-1 RNA levels in patients receiving suppressive antiretroviral therapy. Subjects (n = 10) with long-term HIV-1 suppression receiving combination antiretroviral regimens had their regimens intensified for 4 weeks with raltegravir. Plasma HIV-1 RNA level was determined before, during, and after the 4-week intensification period, using a sensitive assay (limit of detection, 0.2 copies of HIV-1 RNA/mL of plasma). A 4-week intensification course was chosen to investigate potential HIV-1 replication in cells with relatively short (approximately 1-14-day) half-lives. There was no evidence in any subject of a decline in HIV-1 RNA level during the period of raltegravir intensification or of rebound after discontinuation. Median levels of HIV-1 RNA before (0.17 log10 copies/mL), during (0.04 log10 copies/mL), and after (0.04 log10 copies/mL) raltegravir intensification were not significantly different (P > .1 for all comparisons in parametric analyses). High-performance liquid chromatography and mass spectroscopy experiments confirmed that therapeutic levels of raltegravir were achieved in plasma during intensification. Intensification of antiretroviral therapy with a potent HIV-1 integrase inhibitor did not decrease persistent viremia in subjects receiving suppressive regimens, indicating that rapidly cycling cells infected with HIV-1 were not present. Eradication of HIV-1 from infected persons will require new therapeutic approaches. ClinicalTrials.gov identifier: NCT00618371.