Current HIV Research - Volume 16, Issue 6, 2018

Background: Understanding of the restriction of HIV-1 transcription in resting CD4+ Tcells is critical to find a cure for AIDS. Although many negative factors causing HIV-1 transcription blockage in resting CD4+ T-cells have been found, there are still unknown mechanisms to explore. Objective: To explore the mechanism for the suppression of de novo HIV-1 transcription in resting CD4+ T-cells. Methods: In this study, a short isoform of Per-1 expression plasmid was transfected into 293T cells with or without Tat's presence to identify Per-1 as a negative regulator for HIV-1 transcription. Silencing of Per-1 was conducted in resting CD4+ T-cells or monocyte-derived macrophages (MDMs) to evaluate the antiviral activity of Per-1. Additionally, we analyzed the correlation between Per-1 expression and viral loads in vivo, and silenced Per-1 by siRNA technology to investigate the potential anti-HIV-1 roles of Per-1 in vivo in untreated HIV-1-infected individuals. Results: We found that short isoform Per-1 can restrict HIV-1 replication and Tat ameliorates this inhibitory effect. Silencing of Per-1 could upregulate HIV-1 transcription both in resting CD4+ Tcells and MDMs. Moreover, Per-1 expression is inversely correlated with viral loads in Rapid progressors (RPs) in vivo. Conclusion: These data together suggest that Per-1 is a novel negative regulator of HIV-1 transcription. This restrictive activity of Per-1 to HIV-1 replication may contribute to HIV-1 latency in resting CD4+ T-cells.

Background: Mother-to-child transmission of HIV-1 occurs in a minority of HIVinfected mother-infant pairs, even without any interventions. The mechanisms that protect the majority of HIV-exposed infants from infection are unclear. T regulatory cells (Treg) have important immunomodulatory functions, but their role in the fetus as well as in mother-to-child transmission of HIV is under-studied. Methods: We studied available cryopreserved peripheral blood mononuclear cells from HIVexposed infants from the Breastfeeding, Antiretrovirals and Nutrition (BAN) Study cohort in Malawi: 64 infants were HIV-uninfected and 28 infants were HIV-infected at birth. We quantified the frequency of Treg cells (CD4+CD25+FoxP3+), and activated CD4+ and CD8+ T cells (CD38+ HLADR+) by flow cytometry at birth, 6 weeks and 6, 9 and 12 months of age. Descriptive statistics were performed to describe the distributions of these lymphocyte markers according to the HIV infection status; and Student’s t tests and Wilcoxon-Rank Sum tests were performed to compare HIVinfected and uninfected infants. Results: T cell activation increased rapidly in the first 6 weeks of life, more pronounced on CD8+ T cells; a further increase in activation was observed at the time of weaning from breastfeeding at 6 months of age. In contrast, the frequency of Treg was stable over the first 6 weeks of life (median, 0.5%), slightly decreased between 6 weeks and 6 months (median at 6 months, 0.3%) and then slightly increased between 6 months (time of weaning) and 12 months of age (median, 0.45%). HIVinfected infants had significantly higher frequencies of activated T cells than uninfected infants (P < 0.01). At the time of birth, HIV-exposed uninfected infants had higher levels of Treg, compared to infants infected in utero, even though this did not reach statistical significance in this small sample size (P = 0.08). Conclusion: This study provides initial evidence that Treg may play a role in preventing mother-tochild transmission of HIV, likely by suppressing immune activation in the fetus and infant, and needs to be substantiated in a larger study. Better characterization of the role of Treg in fetal and neonatal immunity may provide a valuable complementary approach to achieve eradication of mother-to-child transmission of HIV.

Background: During HIV infection, fusion of the viral and cellular membranes is dependent on folding of the gp41 trimer into a six-helix bundle. Fusion inhibitors, such as the antiretroviral Enfuvirtide (T20), interfere with the formation of the gp41 six-helix bundle. Recent in vitro studies reveal that the gp41 immunodominant region one targeting antibody 3D6 can block T20 interference, but the clinical and pathophysiologic significance of this finding is unclear. Objective/Method: We have previously characterized a number of antibodies that target conformational epitopes on gp41and herein characterized their ability to interfere with T20 in multiple assays and assess their prevalence in HIV infected subjects. Results: The T20 interference by antibody 3D6 was confirmed in a CHO-HXB2 envelope/ HeLaT4+ cell culture assay. Antibodies that target an immunodominant region one epitope, as well as a gp41 discontinuous epitope, also interfered in this assay, however, not all antibodies that targeted these epitopes showed T20 interference. This response was not due to the direct binding of T20 by the antibodies and could not be replicated utilizing TZM-bl and HL2/3 cells. Notably, serum competition studies on a panel of HIV subjects demonstrate that these conformational targeting antibodies are common in the HIV population. Conclusion: The relatively common nature of antibodies targeting these epitopes, the disparate in vitro results, and lack of reported clinical failures ascribed to such antibodies leads us to conclude that antibody interference of T20 is likely not clinically relevant. However, this warrants continued consideration with the advancement of other fusion inhibitors.

Background: Previous studies have developed methodologies for predicting the number of CD4+ cells from the total leukocyte and lymphocytes count based on mathematical methodologies, obtaining percentages of effectiveness prediction higher than 90% with a value of less than 5000 leukocytes. Objective: To improve the methodology probabilities prediction in 5000-9000 leukocytes ranges. Method: from sets A, B, C and D defined in a previous study, and based on CD4+ prediction established on the total number of leukocytes and lymphocytes, induction was performed using data from 10 patients with HIV, redefining the sets A and C that describe the lymphocytes behavior relative to leukocytes. Subsequently, we evaluated with previous research prediction probabilities parameters from a sample of 100 patients, calculating the belonging probability to each sample and organized in predetermined ranges leukocytes, of each of the sets defined, their unions and intersections. Then the same procedure was performed with the new sets and the probability values obtained with the refined method were compared with respect to previously defined, by measures of sensitivity (SENS) and Negative Predictive Value (NPV) for each range. Results: probabilities with values greater than 0.83 were found in five of the nine ranges inside the new sets. The probability for the set A∪C increased from 0.06 to 0.18 which means increases between 0.06 and 0.09 for the intersection (A∪C) ∩ (B∪D), making evident the prediction improvement with new sets defined. Conclusion: The results show that the new defined sets achieved a higher percentage of effectiveness to predict the CD4+ value cells, which represents a useful tool that can be proposed as a substitute for clinical values obtained by the flow cytometry.

Background: To investigate the impact of switching from stable Combined Antiretroviral Therapy (cART) to single-tablet regimen (RPV/FTC/TDF=EVIPLERA® /COMPLERA®) on patient- reported outcomes in HIV-infected adults who cannot tolerate previous cART, in a real-world setting. Methods: PRO-STR is a 48-week observational, prospective, multicenter study. Presence and magnitude of symptoms (main endpoint), health-related quality-of-life (HRQoL), adherence, satisfaction with treatment and patient preferences were assessed. Results: Three hundred patients with 48-week follow-up, who switched to EVIPLERA® (mean age: 46.6 years; male: 74.0%; 74.7% switched from a non-nucleoside reverse-transcriptase-inhibitor, 25.3% from a protease inhibitor + ritonavir) were included. There was no statistical difference in median CD4+ cell count (baseline: 678.5 cells/mm3; 48-week: 683.0 cells/mm3) neither in virological suppression (≤50 copies/mL) (baseline: 98.3%; 48-week: 95.3%). The most frequent reasons for switching were neuropsychiatric (62.3%), gastrointestinal (19.3%) and biochemical/metabolic (19.3%) events. Only 7.7% of patients permanently discontinued therapy. At 48-week, all outcomes showed an improvement compared to baseline. Overall, there was a significant decrease (pvalue≤ 0.05) in number and magnitude of symptoms, while HRQoL, satisfaction and adherence improved significantly. Most patients prefered EVIPLERA® than previous cART. According to the type of intolerance, HRQoL was improved, but only significantly in patients with neuropsychiatric and gastrointestinal symptoms. Adherence improved significantly in patients with metabolic disturbances and satisfaction with EVIPLERA® was higher in the three groups. Conclusion: Switching to EVIPLERA® from non-nucleoside reverse-transcriptase-inhibitor or protease inhibitor-based regimens due to toxicity, improved the presence/magnitude of symptoms, HRQoL, and preference with treatment. EVIPLERA® maintained a virological response, CD4+ cell count and maintained or improved adherence.

Background: Adverse drug reactions (ADRs) associated with antiretroviral therapy (ART) can rapidly reverse the gains of ART resulting in poor health outcomes. We need an improved understanding of specific ART-related ADRs that influence virologic outcomes. Objective: To investigate the frequency of clinical ADRs and assess their effect on virologic failure in patients on ART. Method: We described the prevalence of major clinical ADRs, and the association between specific ADRs and virologic failure in a clinic cohort of HIV-1 infected Nigerians aged ≥18 years, on firstline ART between June 2004 and February 2012. Multivariable logistic regression was run to identify predictors of virologic failure at 24 and 72 weeks of ART. Results: Data of 12,115 patients with a median age of 34 (interquartile range: 29-41) years, and predominantly females (67%) were evaluated. Overall, 957 (7.9%) patients experienced at least one ADR during a median follow-up period of 4 years (interquartile range: 1-7). The three most prevalent ADRs were lipodystrophy (2.6%), anemia (1.9%), and skin rash (0.7%). Virologic failure rate was 36% and 34% at 24 and 72 weeks of ART, respectively. Anemia independently predicted the odds of virologic failure at 72 weeks of ART (adjusted odds ratio, 1.74; 95% CI: 1.2-2.51); adjusted for sex, age, pre-treatment CD4+ cell count, antiretroviral regimen, and medication refill adherence. Conclusion: Antiretroviral therapy-associated anemia increases the likelihood of late virologic failure. We recommend routine monitoring of hemoglobin levels and prompt management of anemia in all patients on ART as a strategy to improve virologic success rates.