HIV-1 viral load blips are of limited clinical significance

Bictegravir/emtricitabine/tenofovir alafenamide as first-line treatment in naïve HIV patients in a rapid-initiation model of care: BIC-NOW clinical trial

OBJECTIVE

Multiple strategies have been utilised to reduce the incidence of HIV, including PrEP and rapid antiretroviral therapy initiation. The study objectives were to evaluate the efficacy, safety, satisfaction, treatment adherence, and system retention obtained with rapid initiation of bictegravir/emtricitabine/tenofovir alafenamide (BIC/FTC/TAF) in naïve patients.

METHODS

This phase IV, multicenter, open-label, single-arm, 48-week clinical trial enrolled patients between January 2020 and June 2022. Adherence to treatment was evaluated with the SMAQ questionnaire and patient satisfaction with the EQ-5D.

RESULTS

Two hundred eight participants were enrolled with mean age of 35.6 years; 87.6% were males; mean CD4 count was 393.5 cells/uL (<200 cells/uL in 22.1%); viral load log was 5.6 (VL>100 000 cop/mL in 43.3%); 22.6% had AIDS, and 4.3% were coinfected with HBV. BIC/FTC/TAF was initiated on the day of their first visit to the HIV specialist in 98.6% of participants, and 9.6% were lost to follow-up. The efficacy at week 48 was 84.1 % by intention-to- treat (ITT), 94.6% by modified ITT, and 98.3% by per protocol analysis. The regimen was discontinued in two subjects (0.9%) during week 1 for grade 3 adverse events. Treatment adherence (weeks 4 [90%, IQR: 80-99%] vs. 48 [90%, IQR: 80-95%; P = 0.49]) and patient satisfaction (weeks 4 [90%, IQR: 80-99%] vs. 48 [90%, IQR: 80-95 P = 0.49]) rates were very high over the 48- week study period.

CONCLUSIONS

BIC/FTC/TAF is an appropriate option for rapid ART initiation in naïve HIV patients, offering high efficacy, safety, durability, treatment adherence, retention in the healthcare system, and patient satisfaction. Number Clinical Trial registration: NCT06177574.

Dolutegravir + Lamivudine vs. Dolutegravir + Tenofovir Disoproxil Fumarate/Emtricitabine: Very-Low-Level HIV-1 Replication through 144 Weeks in the GEMINI-1 and GEMINI-2 Studies

In GEMINI-1/-2, dolutegravir + lamivudine was non-inferior to dolutegravir + tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) in achieving viral suppression (viral load [VL] < 50 copies/mL) in treatment-naive adults. Abbott's RealTime HIV-1 assay provides quantitative VL (40-10,000,000 copies/mL) and qualitative target detected or target not detected (TND) for VL < 40 copies/mL. This post hoc analysis assessed very-low-level viremia and "blips" through Week 144. Proportions with VL < 40 copies/mL and TND are presented overall and by baseline VL and CD4+ cell count. "Blips" (single VL ≥ 50 to <200 copies/mL with adjacent values < 50 copies/mL) were assessed from Day 1 after VL suppression and from Weeks 48 through to 144. Proportions with TND increased through Week 48 and were similar between groups at all visits (Week 144: dolutegravir + lamivudine, 451/716 [63%]; dolutegravir + TDF/FTC, 465/717 [65%]). By observed analysis, TND rates were similar between groups across baseline subgroups. Through Week 144, proportions with ≥1 "blip" were generally comparable for dolutegravir + lamivudine vs. dolutegravir + TDF/FTC from Day 1 (15% vs. 20%) and from Week 48 (7% vs. 11%). Through 144 weeks, the proportions with TND or "blips" were similar between dolutegravir + lamivudine and the three-drug comparator, reinforcing the efficacy and durability of dolutegravir + lamivudine.

Viral Breakthrough Episodes Among Persons with HIV in Care in Alberta, Canada: Clinical and Public Health Implications

Unsuppressed HIV viremia damages immunity and increases the risk for secondary HIV transmission. Successful engagement of persons with HIV (PWH) into care resulting in viral suppression is vital. PWH already engaged in care, who, after achieving viral suppression, experience viral breakthrough episodes (VBEs) with a sequence of suppressed/unsuppressed/suppressed viral loads remain problematic. We examined the frequency and outcomes of PWH experiencing VBE. HIV care is provided at no cost to all patients under Alberta's universal health program. All PWH followed at Southern Alberta Clinic, Canada, with two or more viral load tests between January 1, 2010, and January 1, 2020, were evaluated. Sociodemographic, clinical, and lifestyle variables were determined along with health outcomes (CD4 levels, HIV-related hospitalizations, and HIV/AIDS-related mortality). Descriptive and multi-variable analyses were performed comparing PWH with and without VBEs. Of 2096 PWH, 386 (18%) experienced one or more VBEs. A higher risk of VBEs was seen in adjusted analyses in those diagnosed age ≤40 years. Increased risk of VBE was seen with injection drug use (46%) and in heterosexuals (56%) compared with MSM. Experience of intimate partner violence, unstable housing, homelessness, and past incarceration also increased risks by 36%, 44% 79%, and 51%, respectively. PWH with VBEs experienced lower CD4 counts (median -417/mm³ vs. 576/mm³), higher rates of HIV-related hospitalizations (16% vs. 5%), and a 67% increased risk of death (95% confidence interval 1.17-2.39) over the study period. Nearly 20% of all PWH, after achieving viral suppression, experienced VBEs. Distinct clinical, lifestyle, and life experiences predict PWH at greatest risk for more than one VBEs. Serious negative health outcomes of VBEs were identified, suggesting that novel customized care programming is required for PWH at greatest risk.

Prevention and Initial Management of HIV Infection

Since July 2017, when In the Clinic last addressed management of HIV infection, there have been meaningful improvements in our ability to prevent HIV and to manage patients living with HIV. New approaches to preexposure prophylaxis and more effective treatments have made the elimination of HIV infection a feasible goal. The federal "Ending the HIV Epidemic" initiative aims at a 90% reduction in new HIV diagnoses by 2030. This article provides updated information on how clinicians should use these improvements to manage their patients who are at risk for HIV infection or are newly diagnosed with HIV.

DOLAVI Real-Life Study of Dolutegravir Plus Lamivudine in Naive HIV-1 Patients (48 Weeks)

Brief: Real-world data in naïve HIV-1 patients demonstrate that dolutegravir plus lamivudine in a multiple tablet regimen is effective, safe, and satisfactory; it causes moderately increasing weight and abdominal circumference and is administrable on a test-and-treat strategy. Background: Our objectives were to determine the real-life effectiveness and safety of DT with dolutegravir (50 mg/QD) plus lamivudine (300 mg/QD) in a multiple-tablet regimen (MTR) in naïve PLHIV followed up for 48 weeks and to evaluate the compliance and satisfaction of patients. Material and methods: An open, single-arm, multicenter, non-randomized clinical trial from May 2019 through September 2020 with a 48-week follow-up. Results: The study included 88 PLHIV patients (87.5% male) with a mean age of 35.9 years; 76.1% were MSM patients. The mean baseline CD4 was 516.4 cells/uL, with a viral load (VL) of 4.49 log10, and 11.4% were in the AIDS stage. DT started within 7 days of first specialist consultation in all patients and the same day in 84.1%; 3.4% had baseline resistance mutations (K103N, V106I + E138A, and V108I); 12.5% were lost to follow-up. At week 48, 86.3% had VL < 50 cop/uL by intention-to-treat analysis and 98.7% by per-protocol (PP) analysis. Virological failure (VF) was recorded in 1.1%, with no resistance mutation. One blip was detected in 5.2% without VF. Three reported anxiety, dizziness, and cephalgia, respectively, at week 4 and one reported insomnia at week 24; none reported adverse events at week 48. The mean weight was 4 kg higher at 48 weeks (p = 0.0001) and abdominal circumference 3 cm larger at 24 weeks (p = 0.022). No forgetfulness occurred in 98.7% of patients. Patient satisfaction was 90/100 at 4, 24, and 48 weeks. Conclusion: Real-world data demonstrate that dolutegravir plus lamivudine in MTR is effective, safe, and satisfactory, moderately increasing weight and abdominal circumference and administrable on a test-and-treat strategy.

Low-level viremia in treated HIV-1 infected patients: advances and challenges

Antiretroviral therapy (ART) can effectively suppress HIV-1 replication, improving quality of life and restoring the lifespan of persons living with HIV (PLWH) to near normal levels. However, after standardized ART, a low level of HIV-1 RNA, i.e., low-level viremia (LLV), may still be identified in 3% to 10% of the patients. LLV is capable of impacting the immunological and clinical outcome of patients and serves as a risk factor for transmission. The underlying mechanism of LLV is not yet certain, and the effects of LLV on patient outcomes remain under evaluation. Understanding LLV will allow effective prevention and control strategies to be designed for the benefit of PLWH.

Characteristics of Agreements to have Condomless Anal Intercourse in the Presence of an Undetectable Viral Load Among HIV Serodiscordant Male Couples in Australia, Brazil and Thailand

The use of undetectable viral load (VL) to negotiate condomless anal intercourse (CLAI) in HIV serodiscordant male relationships has become more common as more data regarding the effectiveness of antiretroviral treatments for the prevention of HIV transmission has been described. We examined viral load agreements (VLAs) for condomless sex in the presence of an undetectable VL in 343 HIV serodiscordant male couples in Australia, Brazil and Thailand. Factors associated with having a VLA included having agreements for the HIV-positive partner to report his VL result (p < 0.001), agreeing that VL affects agreements about sexual practice (p < 0.001), the HIV-negative partner's perception of his partner's undetectable VL (p < 0.001), the couple's belief in the efficacy of undetectable VL in preventing HIV transmission (p < 0.001), and the couple engaging in CLAI with each other (p < 0.001). Over time, these agreements became more common although 49.3% of couples in the sample never had a viral load agreement. As these agreements become more common, further education is required to support male couples in using them safely.

Virological measures and factors associated with outcomes, and missing outcome data in HIV clinical trials: a methodological study

BACKGROUND

To evaluate the definition of HIV virological outcomes in the literature and factors associated with outcomes and missing outcome data.

METHODS

We conducted a methodological review of HIV RCTs using a search (2009-2019) of PubMed, Embase and the Cochrane Central Register of Controlled Trials.Only full-text, peer-reviewed, randomised controlled trials (RCTs) that measured virological outcomes in people living with HIV, and published in English were included.We extracted study details and outcomes. We used logistic regression to identify factors associated with a viral threshold ≤50 copies/mL and linear regression to identify factors associated with missing outcome data.

RESULTS

Our search yielded 5847 articles; 180 were included. A virological outcome was the primary outcome in 73.5% of studies. 89 studies (49.4%) used virological success. The remaining used change in viral load (VL) (33 studies, 18.3%); virological failure (59 studies, 32.8%); or virological rebound (9 studies, 5.0%). 96 studies (53.3%) set the threshold at ≤50 copies/mL; and 33.1% used multiple measures.Compared with government and privately funded studies, RCTs with industry funding (adjusted OR 6.39; 95% CI 2.15 to 19.00; p<0.01) were significantly associated with higher odds of using a VL threshold of ≤50 copies/mL. Publication year, intervention type, income level and number of patients were not associated with a threshold of ≤50 copies/mL. Trials with pharmacological interventions had less missing data (β=-11.04; 95% CI -20.02 to -1.87; p=0.02).

DISCUSSION

Country source of funding was associated with VL threshold choice and studies with pharmacological interventions had less missing data, which may in part explain heterogeneous virological outcomes across studies. Multiple measures of VL were not associated with missing data. The development of formal guidelines on virological outcome reporting in RCTs is needed.

Redefining therapeutic success in HIV patients: an expert view

Thanks to advances in the field over the years, HIV/AIDS has now become a manageable chronic condition. Nevertheless, a new set of HIV-associated complications has emerged, related in part to the accelerated ageing observed in people living with HIV/AIDS, the cumulative toxicities from exposure to antiretroviral drugs over decades and emerging comorbidities. As a result, HIV/AIDS can still have a negative impact on patients' quality of life (QoL). In this scenario, it is reasonable to believe that the concept of therapeutic success, traditionally associated with CD4 cell count restoration and HIV RNA plasma viral load suppression and the absence of drug resistances, needs to be redefined to include other factors that reach beyond antiretroviral efficacy. With this in mind, a group of experts initiated and coordinated the RET Project, and this group, using the available evidence and their clinical experience in the field, has proposed new criteria to redefine treatment success in HIV, arranged into five main concepts: rapid initiation, efficacy, simplicity, safety, and QoL. An extensive review of the literature was performed for each category, and results were discussed by a total of 32 clinicians with experience in HIV/AIDS (4 coordinators + 28 additional experts). This article summarizes the conclusions of these experts and presents the most updated overview on the five topics, along with a discussion of the experts' main concerns, conclusions and/or recommendations on the most controversial issues.

Understanding the Risk of Human Immunodeficiency Virus (HIV) Virologic Failure in the Era of Undetectable Equals Untransmittable

The “Undetectable = Untransmittable” campaign indicates that persons living with Human Immunodeficiency Virus (HIV) who maintain a suppressed viral load cannot sexually transmit the virus. However, there is little knowledge of the percent of individuals at a population level who sustain viral suppression long term. The aims of this study were to: (1) establish a baseline of persons living with diagnosed HIV who resided in New York and had consecutive suppressed viral load tests; (2) describe the risk of virologic failure among those who were consecutively suppressed; and (3) gain an understanding of the length of time between consecutive viral suppression to virologic failure. A total of 102,339 New Yorkers aged 13–90 years were living with diagnosed HIV at the beginning of 2012; 47.9% were consecutively suppressed (last two HIV viral load test results from 2010–2011 that were < 420 days apart and < 200 copies/mL). Of consecutively suppressed individuals, 54.3% maintained viral suppression for the entire study period and 33.6% experienced virologic failure during the study period. Among persons who experienced virologic failure, 82.6% did so six or more months after being consecutively suppressed. Our findings support the need for ongoing viral load monitoring, adherence support, and ongoing risk reduction messaging to prevent forward HIV transmission.

Persistent Low-level Viremia While on Antiretroviral Therapy Is an Independent Risk Factor for Virologic Failure

BACKGROUND

Whether persistent low-level viremia (pLLV) predicts virologic failure (VF) is unclear. We used data from the US Military HIV Natural History Study (NHS), to examine the association of pLLV and VF.

METHODS

NHS subjects who initiated combination antiretroviral therapy (ART) after 1996 were included if they had 2 or more VLs measured with a lower limit of detection of ≤50 copies/mL. VF was defined as a confirmed VL ≥200 copies/mL or any VL >1000 copies/mL. Participants were categorized into mutually exclusive virologic categories: intermittent LLV (iLLV) (VL of 50-199 copies/mL on <25% of measurements), pLLV (VL of 50-199 copies/mL on ≥25% of measurements), high-level viremia (hLV) (VL of 200-1000 copies/mL), and continuous suppression (all VL <50 copies/mL). Cox proportional hazards models were used to evaluate the association between VF and LLV; hazard ratios and 95% confidence interval (CI) are presented.

RESULTS

Two thousand six subjects (median age 29.2 years, 93% male, 41% black) were included; 383 subjects (19%) experienced VF. After adjusting for demographics, VL, CD4 counts, ART regimen, prior use of mono or dual antiretrovirals, and time to ART start, pLLV (3.46 [2.42-4.93]), and hLV (2.29 [1.78-2.96]) were associated with VF. Other factors associated with VF include black ethnicity (1.33 [1.06-1.68]) and antiretroviral use prior to ART (1.79 [1.34-2.38]). Older age at ART initiation (0.71 [0.61-0.82]) and non-nucleoside reverse transcriptase inhibitor (0.68 [0.51-0.90]) or integrase strand transfer inhibitor use (0.26 [0.13-0.53]) were protective.

CONCLUSION

Our data add to the body of evidence that suggests persistent LLV is associated with deleterious virologic consequences.

Outcomes of immunomodulatory and biologic therapy in people living with HIV

OBJECTIVES

Immunomodulatory drugs (IMDs) are crucial for treating autoimmune, inflammatory, and oncologic conditions. Data regarding the safety of IMDs in people living with HIV (PLWH) are limited. We describe outcomes in all PLWH prescribed these agents from 2000--2019 at two academic medical centers.

DESIGN

Retrospective cohort study.

METHODS

We systematically identified and reviewed charts of all PLWH receiving IMDs. We defined a treatment episode as an uninterrupted period on an IMD regimen. We quantified infections, blips (detectable plasma HIV RNA following an undetectable result), and virologic failure (progression from plasma HIV RNA <200 copies/ml to two consecutive values >200 copies/ml despite ART).

RESULTS

Seventy-seven patients contributed 110 treatment episodes. Rheumatologic comorbidities were the most frequent indication. The most common IMD classes were TNF inhibitors, antimetabolites, and checkpoint inhibitors. Ninety percent of treatment episodes involved concomitant ART. Median pretreatment CD4 T-cell count was 609 cells/μl (IQR 375--861). Among 51 treatment episodes on ART with undetectable pretreatment plasma HIV RNA, HIV became detectable within 1 year in 21 of 51 cases (41.2%); there were no instances of virologic failure. Compared with other agents, treatment episodes involving checkpoint inhibitors were more likely to involve a blip (77.8 vs. 33.3%, P = 0.015). Thirteen treatment episodes (11.8%) were associated with concomitant infection; none was attributed to IMDs by the treating clinician.

CONCLUSION

PLWH treated with IMDs should be monitored carefully for virologic blips and incident infections. Checkpoint inhibitors may be associated with a higher rate of viral blips, although the clinical significance is unclear.

Drug Resistance Among Adolescents and Young Adults with Virologic Failure of First-Line Antiretroviral Therapy and Response to Second-Line Treatment

Barriers to sustainable virologic suppression (VS) of HIV-infected adolescents and young adults include drug resistance mutations (DRMs) and limited treatment options, which may impact the outcome of second-line antiretroviral therapy (ART). We sequenced plasma viral RNA from 74 adolescents and young adults (16-24 years) failing first-line ART at Newlands Clinic, Zimbabwe between October 2015 and December 2016. We evaluated first-line nucleoside reverse transcriptase inhibitor (NRTI) susceptibility scores to first- and second-line regimens. Boosted protease inhibitor (bPI)-based ART was provided and viral load (VL) monitored for ≥48 weeks. Fisher's exact test was used to evaluate factors associated with VS on second-line regimens, defined as VL <1,000 copies/mL (VS_1,000) or <50 copies/mL (VS₅₀). The 74 participants on first-line ART had a median [interquartile range (IQR)] age of 18 (16-21) years and 42 (57%) were female. The mean (±standard deviation) duration on ART was 5.5 (±3.06) years and the median (IQR) log₁₀ VL was 4.26 (3.78-4.83) copies/mL. After switching to a second-line PI regimen, 88% suppressed to <1,000 copies/mL and 76% to <50 copies/mL at ≥48 weeks. A new NRTI was associated with increased VS₅₀ (p = .031). These 74 adolescents and young adults failing first-line ART demonstrated high levels (97%) of DRMs, despite enhanced adherence counseling. Switching to new NRTIs in second-line improved VS. With the widespread adoption of generic dolutegravir, lamivudine and tenofovir combinations in Africa, genotyping to determine NRTI susceptibility, may be warranted.

Modeling HIV Transmission from Sexually Active Alcohol-Consuming Men in ART Programs to Seronegative Wives

BACKGROUND

The rollout of antiviral therapy in Low and Middle Income Countries (LMICs) has reduced HIV transmission rates at the potential risk of resistant HIV transmission. We sought to predict the risk of wild type and antiviral resistance transmissions in these settings.

METHODS

A predictive model utilizing viral load, ART adherence, genital ulcer disease, condom use, and sexual event histories was developed to predict risks of HIV transmission to wives of 233 HIV+ men in 4 antiretroviral treatment centers in Maharashtra, India.

RESULTS

ARV Therapy predicted a 5.71-fold reduction in transmissions compared to a model of using condoms alone, with 79.9%, of remaining transmissions resulting in primary ART-resistance.

CONCLUSIONS

ART programs reduce transmission of HIV to susceptible partners at a substantial increased risk for transmission of resistant virus. Enhanced vigilance in monitoring adherence, use of barrier protections, and viral load may reduce risks of resistant HIV transmissions in LMIC settings.

Multicenter evaluation of the cobas® HIV-1 quantitative nucleic acid test for use on the cobas® 4800 system for the quantification of HIV-1 plasma viral load

BACKGROUND AND OBJECTIVES

Measurement of HIV-1 viral load (VL) is necessary to monitor treatment efficacy in patients receiving antiretroviral therapy. We evaluated the performance of the cobas® HIV-1 quantitative nucleic acid test for use on the cobas® 4800 system ("cobas 4800 HIV-1").

METHODS

Limit of detection, linearity, accuracy, precision, and specificity of cobas 4800 HIV-1, COBAS® AmpliPrep/COBAS® Taqman® HIV-1 version 2.0 (CAP/CTM HIV-1 v2) and Abbott RealTime HIV-1 were determined in one or two out of three sites.

RESULTS

The limit of detection of the cobas 4800 HIV-1 for 400 μL and 200 μL input volumes was 14.2 copies/mL (95% CI: 12.5-16.6 copies/mL) and 43.9 copies/mL (37.7-52.7 copies/mL), respectively. Cobas 4800 HIV-1 demonstrated 100% specificity, and results were linear for all analyzed group M HIV-1 subtypes. Precision was high (SD < 0.19 log₁₀) across all measured ranges, reagent lots and input volumes. Correlation between cobas 4800 HIV-1 and CAP/CTM HIV-1 v2 or RealTime HIV-1 was high (R² ≥ 0.95). Agreement between cobas 4800 HIV-1 and CAP/CTM HIV-1 v2 was 96.5% (95.0%-97.7%) at a threshold of 50 copies/mL, and 97.2% (95.8%-98.3%) at 200 copies/mL. Agreement between cobas 4800 HIV-1 and RealTime HIV-1 was 96.6% (93.4%-98.5%) at 50 copies/mL, and 97.0% (94.0%-98.8%) at 200 copies/mL. The mean difference between cobas 4800 HIV-1 and CAP/CTM HIV-1 v2 or RealTime HIV-1 was -0.10 log₁₀ or 0.01 log₁₀, respectively.

CONCLUSIONS

The cobas 4800 HIV-1 test is highly sensitive, accurate and correlated well with other assays, including agreement around clinically relevant thresholds, indicating minimal overall VL quantification differences between tested platforms.

Stochastic Modeling and Simulation of Viral Evolution

RNA viruses comprise vast populations of closely related, but highly genetically diverse, entities known as quasispecies. Understanding the mechanisms by which this extreme diversity is generated and maintained is fundamental when approaching viral persistence and pathobiology in infected hosts. In this paper, we access quasispecies theory through a mathematical model based on the theory of multitype branching processes, to better understand the roles of mechanisms resulting in viral diversity, persistence and extinction. We accomplish this understanding by a combination of computational simulations and the theoretical analysis of the model. In order to perform the simulations, we have implemented the mathematical model into a computational platform capable of running simulations and presenting the results in a graphical format in real time. Among other things, we show that the establishment of virus populations may display four distinct regimes from its introduction into new hosts until achieving equilibrium or undergoing extinction. Also, we were able to simulate different fitness distributions representing distinct environments within a host which could either be favorable or hostile to the viral success. We addressed the most used mechanisms for explaining the extinction of RNA virus populations called lethal mutagenesis and mutational meltdown. We were able to demonstrate a correspondence between these two mechanisms implying the existence of a unifying principle leading to the extinction of RNA viruses.

Medication nonadherence, multitablet regimens, and food insecurity are key experiences in the pathway to incomplete HIV suppression

OBJECTIVE

To identify potential pathways by which a variety of factors act to lead to unsuppressed viral load.

DESIGN

A prospective cohort of HIV-HCV co-infected adults receiving care from 18 HIV clinics across Canada was followed every 6 months between November 2012 and October 2015. Participants with at least two visits while receiving combined antiretroviral treatment (cART) were included.

METHODS

A path analysis was conducted on the basis of ordered sequences of multivariate logistic regressions using generalized estimating equations. The first regression model used incomplete viral suppression (viral load >50 copies/ml) as the outcome of interest and all other variables (i.e. nonadherence, food insecurity, treatment attributes, and other sociodemographic, behavioural, and clinical factors) as potential predictors. Any variable determined to be a statistically significant predictor of incomplete viral suppression was then used as the next outcome of interest in the subsequent regression, until all predictors of each selected outcome were purely explanatory variables.

RESULTS

A total of 566 participants had at least two visits. Drivers of incomplete viral suppression included injection drug use, age 45 years or less, living alone, poor health status, longer duration of HIV infection and baseline CD4 cell count less than 200 cells/μl. Nonadherence, food insecurity, and the use of multitablet regimens mediated the effects of these factors on incomplete viral suppression.

CONCLUSION

Our results suggest that nonadherence, multitablet regimens, and food insecurity are key points in the pathway to incomplete HIV suppression. These are potentially amenable intervention targets that would not be revealed using traditional regression analyses.

When do models of NeuroAIDS faithfully imitate "the real thing"?

HIV-infected patients treated with antiretroviral medicines (ART) still face neurological challenges. HIV-associated neurocognitive disturbances (HAND) can occur, and latent viral DNA persisting in the central nervous system (CNS) prevents eradication of HIV. This communication focuses on how to develop experimental models of HAND and CNS HIV latency that best imitate the CNS pathophysiology in diseased humans, which we take to be “the real thing.” Models of HIV encephalitis (HIVE) with active CNS viral replication were developed in the early years of the AIDS pandemic. The clinical relevancy of such models is in sharp decline because HIVE seldom occurs in virally suppressed patients, while HAND remains common. The search for improved models of HAND should incorporate the neurochemical, neuroimmunological and neuropathological features of virally suppressed patients. Common anomalies in these patients as established in autopsy brain specimens include brain endothelial cell activation and neurochemical imbalances of synaptic transmission; classical neurodegeneration may not be as crucial. With regard to latent HIV with viral suppression, human brain specimens show that the pool of latent proviral HIV DNA in the CNS is relatively small relative to the total body pool and does not change substantially over years. The CNS pool of latent virus probably differs from lymphoid tissues, because the mononuclear phagocyte system sustains productive infection (versus lymphocytes). These and yet-to-be discovered aspects of the human CNS of virally suppressed patients need to be better defined and addressed in experimental models. To maintain clinical relevancy, models of HAND and viral latency should faithfully emulate “the real thing.”

Management of Newly Diagnosed HIV Infection

No field in medicine has moved as swiftly as HIV/AIDS over the past 35 years. Because of the rapid turnover of key information, this In the Clinic focuses on essential principles of care for newly diagnosed adults with HIV-1 infection and how to prevent infection in persons at risk. To ensure continued usefulness, future directions in therapy and how to access updated information on a continuous basis are emphasized.

Yield of yearly routine physical examination in HIV-1 infected patients is limited: A retrospective cohort study in the Netherlands

Background

Routine physical examinations might be of value in HIV-infected patients, but the yield is unknown. We determined the diagnoses that would have been missed without performing annual routine physical examinations in HIV-infected patients with stable disease.

Methods

Data were collected from the medical records of 299 HIV-1-infected patients with CD4 count >350 cells/mm³ if not using combination antiretroviral therapy (cART), or CD4 count >100 cells/mm3 and undetectable viral load if using cART. We defined the diagnoses that would have been missed without performing routine physical examinations on annual check-ups in 2010. Exclusion criteria were hepatitis B/C co-infection, start/ switch of cART < 24 weeks, pregnancy, and transgenderism.

Results

215 patients (72%) had positive findings: lipodystrophy (30%), lymphadenopathy (16%) and hypertension (8.4%) were the most common. Two-thirds of all findings were not new or were based on complaints indicating a physical examination even if not routinely scheduled. For 24 patients (8.0%) the routine physical examination led to the finding of a new diagnosis: six—all men who have sex with men (MSM)—had a concurrent sexually transmitted infection, eight had hypertension, and ten others had a large variety of diagnoses. A total atrioventricular block with bradycardia was the most clinically relevant finding.

Conclusions

Annual physical examinations of HIV-infected patients with stable disease brought few new diagnoses that would have been missed without performing a routine examination. Our results suggest that standard assessments could be restricted to six-monthly measuring blood pressure in all patients and annually performing anogenital and digital rectal examination on MSM.

TURQUOISE-I Part 1b: Ombitasvir/Paritaprevir/Ritonavir and Dasabuvir with Ribavirin for Hepatitis C Virus Infection in HIV-1 Coinfected Patients on Darunavir

Background

Ombitasvir/paritaprevir/ritonavir with dasabuvir (OBV/PTV/r + DSV) ± ribavirin (RBV) is approved for hepatitis C virus (HCV) genotype 1 (GT1) treatment in HIV-1 coinfected patients. In healthy controls, coadministration of OBV/PTV/r + DSV + darunavir (DRV) lowered DRV trough concentration (Ctrough) levels. To assess the clinical significance of this change, TURQUOISE-I, Part 1b, evaluated the efficacy and safety of OBV/PTV/r + DSV + RBV in coinfected patients on stable, DRV-containing antiretroviral therapy (ART).

Methods

Patients were HCV treatment-naive or interferon-experienced, had CD4+ lymphocyte count ≥200 cells/µL or ≥14%, and plasma HIV-1 RNA suppression on once-daily (QD) DRV-containing ART at screening. Patients were randomized to maintain DRV 800 mg QD or switch to twice-daily (BID) DRV 600 mg; all received OBV/PTV/r + DSV + RBV for 12 weeks.

Results

Twenty-two patients were enrolled and achieved SVR12. No adverse events led to discontinuation. Coadministration had minimal impact on DRV maximum observed plasma concentration and area under the curve; DRV Ctrough levels were slightly lower with DRV QD and BID. No patient experienced plasma HIV-1 RNA >200 copies/mL during treatment.

Conclusions

HCV GT1/HIV-1 coinfected patients on stable DRV-containing ART achieved 100% SVR12 while maintaining plasma HIV-1 RNA suppression. Despite DRV exposure changes, episodes of intermittent HIV-1 viremia were infrequent.

No detectable resistance to tenofovir disoproxil fumarate in HBeAg+ and HBeAg- patients with chronic hepatitis B after 8 years of treatment

A major hurdle in the long-term treatment of chronic hepatitis B (CHB) patients is to maintain viral suppression in the absence of drug resistance. To date, no evidence of resistance to tenofovir disoproxil fumarate (TDF) has been observed. A cumulative evaluation of CHB patients who qualified for resistance surveillance over 8 years of TDF treatment was conducted. Patients in studies GS-US-174-0102 (HBeAg-) and GS-US-174-0103 (HBeAg+) were randomized 2:1 to receive TDF or adefovir dipivoxil (ADV) for 48 weeks followed by open-label TDF through year 8. Population sequencing of HBV pol/RT was attempted for all TDF-treated patients at baseline and, annually if viremic, at discontinuation, or with addition of emtricitabine. Overall, 88/641 (13.7%) patients qualified for sequence analysis at one or more time points. The percentage of patients qualifying for sequence analysis declined over time, from 9 to 11% in years 1-2 to <4% over years 3-8. Forty-one episodes of virologic breakthrough (VB) occurred throughout the study, with most (n=29, 70%) associated with nonadherence to study medication. Fifty-nine per cent of VB patients with an opportunity to resuppress HBV achieved HBV DNA resuppression. A minority of patients who qualified for sequencing had polymorphic (41/165, 24.8%) or conserved (17/165, 10.3%) site changes in pol/RT, with six patients developing lamivudine and/or ADV resistance-associated mutations. No accumulation of conserved site changes was detected. The long-term treatment of CHB with TDF monotherapy maintains effective suppression of HBV DNA through 8 years, with no evidence of TDF resistance or accumulation of conserved site changes.

Monocyte Activation Is Associated With Worse Cognitive Performance in HIV-Infected Women With Virologic Suppression

BACKGROUND

 Cognitive impairment persists despite suppression of plasma human immunodeficiency virus (HIV) RNA. Monocyte-related immune activation is a likely mechanism. We examined immune activation and cognition in a cohort of HIV-infected and uninfected women from the Women's Interagency HIV Study (WIHS).

METHODS

 Blood levels of activation markers, soluble CD163 (sCD163), soluble CD14 (sCD14), CRP, IL-6, and a gut microbial translocation marker (intestinal fatty acid binding protein (I-FABP)) were measured in 253 women (73% HIV-infected). Markers were compared to concurrent (within ± one semiannual visit) neuropsychological testing performance.

RESULTS

 Higher sCD163 levels were associated with worse overall performance and worse verbal learning, verbal memory, executive function, psychomotor speed, and fine motor skills (P < .05 for all comparisons). Higher sCD14 levels were associated with worse verbal learning, verbal memory, executive function, and psychomotor speed (P < .05 for all comparisons). Among women with virological suppression, sCD163 remained associated with overall performance, verbal memory, psychomotor speed, and fine motor skills, and sCD164 remained associated with executive function (P < .05 for all comparisons). CRP, IL-6, and I-FABP were not associated with worse cognitive performance.

CONCLUSIONS

 Monocyte activation was associated with worse cognitive performance, and associations persisted despite viral suppression. Persistent inflammatory mechanisms related to monocytes correlate to clinically pertinent brain outcomes.

Recent Insights into the HIV/AIDS Pandemic

Etiology, transmission and protection: Transmission of HIV, the causative agent of AIDS, occurs predominantly through bodily fluids. Factors that significantly alter the risk of HIV transmission include male circumcision, condom use, high viral load, and the presence of other sexually transmitted diseases. Pathology/Symptomatology: HIV infects preferentially CD4+ T lymphocytes, and Monocytes. Because of their central role in regulating the immune response, depletion of CD4+ T cells renders the infected individual incapable of adequately responding to microorganisms otherwise inconsequential. Epidemiology, incidence and prevalence: New HIV infections affect predominantly young heterosexual women and homosexual men. While the mortality rates of AIDS related causes have decreased globally in recent years due to the use of highly active antiretroviral therapy (HAART) treatment, a vaccine remains an elusive goal. Treatment and curability: For those afflicted HIV infection remains a serious illness. Nonetheless, the use of advanced therapeutics have transformed a dire scenario into a chronic condition with near average life spans. When to apply those remedies appears to be as important as the remedies themselves. The high rate of HIV replication and the ability to generate variants are central to the viral survival strategy and major barriers to be overcome. Molecular mechanisms of infection: In this review, we assemble new details on the molecular events from the attachment of the virus, to the assembly and release of the viral progeny. Yet, much remains to be learned as understanding of the molecular mechanisms used in viral replication and the measures engaged in the evasion of immune surveillance will be important to develop effective interventions to address the global HIV pandemic.

Which adherence measure - self-report, clinician recorded or pharmacy refill - is best able to predict detectable viral load in a public ART programme without routine plasma viral load monitoring?

OBJECTIVE

Combination antiretroviral therapy (cART) suppresses viral replication to an undetectable level if a sufficiently high level of adherence is achieved. We investigated which adherence measurement best distinguishes between patients with and without detectable viral load in a public ART programme without routine plasma viral load monitoring.

METHOD

We randomly selected 870 patients who started cART between May 2009 and April 2012 in 10 healthcare facilities in Addis Ababa, Ethiopia. Six hundred and sixty-four (76.3%) patients who were retained in HIV care and were receiving cART for at least 6 months were included and 642 had their plasma HIV-1 RNA concentration measured. Patients' adherence to cART was assessed according to self-report, clinician recorded and pharmacy refill measures. Multivariate logistic regression model was fitted to identify the predictors of detectable viremia. Model accuracy was evaluated by computing the area under the receiver operating characteristic (ROC) curve.

RESULT

A total of 9.2% and 5.5% of the 642 patients had a detectable viral load of ≥40 and ≥400 RNA copies/ml, respectively. In the multivariate analyses, younger age, lower CD4 cell count at cART initiation, being illiterate and widowed, and each of the adherence measures were significantly and independently predictive of having ≥400 RNA copies/ml. The ROC curve showed that these variables altogether had a likelihood of more than 80% to distinguish patients with a plasma viral load of ≥400 RNA copies/ml from those without.

CONCLUSION

Adherence to cART was remarkably high. Self-report, clinician recorded and pharmacy refill non-adherence were all significantly predictive of detectable viremia. The choice for one of these methods to detect non-adherence and predict a detectable viral load can therefore be based on what is most practical in a particular setting.

CSF/plasma HIV-1 RNA discordance even at low levels is associated with up-regulation of host inflammatory mediators in CSF

•

Discordant HIV in CSF is associated with raised inflammatory mediators in CSF.

•

CSF mediators are raised with discordance both at high and low levels.

•

Discordance on ultrasensitive testing can also be also associated with raised mediators.

Introduction

HIV-1 RNA can be found at higher levels in cerebrospinal fluid (CSF) than in plasma, termed CSF/plasma discordance. The clinical significance of CSF/plasma discordance is not known and the degree of discordance considered important varies. We aimed to determine whether a panel of CSF cytokines, chemokines and associated mediators were raised in patients with CSF/plasma discordance at different levels.

Methods

A nested case-control study of 40 CSF samples from the PARTITION study. We used a cytometric bead array to measure CSF mediator concentrations in 19 discordant and 21 non-discordant samples matched for plasma HIV-1 RNA. Discordant samples were subdivided into ‘high discordance’ (>1log₁₀) and ‘low discordance’ (0.5–1log₁₀, or ultrasensitive discordance). CSF mediators significant in univariate analysis went forward to two-way unsupervised hierarchical clustering based on the patterns of relative mediator concentrations.

Results

In univariate analysis 19 of 21 CSF mediators were significantly higher in discordant than non-discordant samples. There were no significant differences between samples with high versus low discordance. The samples grouped into two clusters which corresponded to CSF/plasma discordance (p < 0.0001). In cluster one all mediators had relatively high abundance; this included 18 discordant samples and three non-discordant samples. In cluster two all mediators had relatively low abundance; this included 18 non-discordant samples and one non-discordant sample with ultrasensitive discordance only.

Conclusions

CSF/plasma discordance is associated with potentially damaging neuroinflammatory process. Patients with discordance at lower levels (ie. 0.5–1log₁₀) should also be investigated as mediator profiles were similar to those with discordance >1log₁₀. Sensitive testing may have a role to determine whether ultrasensitive discordance is present in those with low level CSF escape.

Frequent Episodes of Detectable Viremia in HIV Treatment-Experienced Children is Associated with a Decline in CD4+ T-cells Over Time

BACKGROUND

The clinical consequences of the magnitude and the duration of detectable viremia in HIV-infected children have not been well characterized. We examined the predictors and immunologic consequences over time of frequent episodes of detectable viremia in HIV-infected children followed at Yale-New Haven Hospital.

METHODS

We analyzed the CD4+ T-cell and HIV viral load over a 19-year period (1996 to 2013) of 104 HIV-infected children enrolled in the Yale Prospective Longitudinal Pediatric HIV Cohort. Both CD4+ T-lymphocytes and HIV viral load were measured at clinic visits every 3 to 4 months. Longitudinal data analyses using polynomial random coefficients models were conducted to examine overtime changes in CD4+ T-cell counts by frequency of episodes of detectable viremia. Moreover, regression analyses using logistic regression models were used to assess the predictors of frequent episodes of detectable viremia.

RESULTS

One hundred and four (104) HIV-infected children with more than one HIV viral load measurement between 1996 and November 2013 were included in the analysis. Over 80% (N=86) of the children had detectable viral load (HIV RNA viral load ≥50 copies/ml) during more than 50% of their clinic visits. Children with infrequent episodes of detectable viremia had significantly higher CD4+ T-cell counts overtime compared to those with frequent episodes of detectable viremia (P<0.0001).

CONCLUSIONS

Both frequency and magnitude of episodes of detectable viremia had effect on CD4+ T-cells. Strict adherence to a treatment goal of undetectable HIV viremia in children is likely to be beneficial.

Factors associated with HIV viral load "blips" and the relationship between self-reported adherence and efavirenz blood levels on blip occurrence: a case-control study

Background

The uncertain etiology of HIV viral load (VL) blips may lead to increased use of clinical resources. We evaluated the association of self-reported adherence (SRA) and antiretroviral (ART) drug levels on blip occurrence in US Military HIV Natural History Study (NHS) participants who initiated the single-tablet regimen efavirenz/emtricitabine/tenofovir disoproxil fumarate (EFV/FTC/TDF).

Methods

ART-naïve NHS participants started on EFV/FTC/TDF between 2006 and 2013 who achieved VL suppression (<50 copies/mL) within 12 months and had available SRA and stored plasma samples were included. Participants with viral blips were compared with those who maintained VL suppression without blips. Untimed EFV plasma levels were evaluated on consecutive blip and non-blip dates by high performance liquid chromatography, with a level ≥1 mcg/mL considered therapeutic. SRA was categorized as ≥85 or <85 %. Descriptive statistics were performed for baseline characteristics and univariate and multivariate Cox proportional hazard models were used to assess the relationship between covariates and blip occurrence.

Results

A total of 772 individuals met inclusion criteria, including 99 (13 %) blip and 673 (87 %) control participants. African-American was the predominant ethnicity and the mean age was 29 years for both groups. SRA ≥ 85 % was associated with therapeutic EFV levels at both blip and non-blip time points (P = 0.0026); however no association was observed between blips and SRA or EFV levels among cases. On univariate analysis of cases versus controls, blips were associated with higher mean pre-treatment VL (HR 1.45, 95 % CI 1.11–1.89) and pre-treatment CD4 count <350 cells/µL (68.1 vs 49.7 %). Multivariate analysis also showed that blips were associated with a higher mean VL (HR 1.42, 95 % CI 1.08–1.88; P = 0.0123) and lower CD4 count at ART initiation, with CD4 ≥500 cells/µL having a protective effect (HR 0.45, 95 % CI 0.22–0.95; P = 0.0365). No association was observed for demographic characteristics or SRA.

Conclusion

Blips are commonly encountered in the clinical management of HIV-infected patients. Although blip occurrence was not associated with SRA or EFV blood levels in our study, blips were associated with HIV-related factors of pre-ART high VL and low CD4 count. Additional studies are needed to determine the etiology of blips in HIV-infected patients.

Measuring the HIV Care Continuum Using Public Health Surveillance Data in the United States

The HIV care continuum is a critical framework for situational awareness of the HIV epidemic; yet challenges to accurate enumeration of continuum components hamper continuum estimation in practice. We describe local surveillance-based estimation of the HIV continuum in the United States, reviewing common practices as recommended by the Centers for Disease Control and Prevention. Furthermore, we review some challenges and biases likely to threaten existing continuum estimates. Current estimates rely heavily on the use of CD4 cell count and HIV viral load laboratory results reported to surveillance programs as a proxy for receipt of HIV-related outpatient care. As such, continuum estimates are susceptible to bias because of incomplete laboratory reporting and imperfect sensitivity and specificity of laboratory tests as a proxy for routine HIV care. Migration of HIV-infected persons between jurisdictions also threatens the validity of continuum estimates. Data triangulation may improve but not fully alleviate biases.

High level of virological suppression among HIV-infected adults receiving combination antiretroviral therapy in Addis Ababa, Ethiopia

BACKGROUND

Plasma viral load (pVL) is a key indicator of therapeutic response in HIV-infected patients receiving combination antiretroviral therapy (cART), but is often unavailable in routine clinical care in resource-limited settings. Previous model-based simulation studies have suggested that the benefits of routine pVL monitoring among patients on first-line regimens in resource-limited settings are modest, but this needs corroboration in well-defined study populations.

METHODS

We investigated virological suppression levels and identified predictors of detectable viraemia among 870 randomly selected patients who started cART between May 2009 and April 2012 in 10 health-care facilities in Addis Ababa, Ethiopia. A total of 656 (75.4%) patients, who were alive, were retained in HIV care and receiving cART for at least 6 months provided a blood sample for pVL measurement. Predictors of detectable viraemia were identified in a multivariate logistic regression model.

RESULTS

In on-treatment analysis, 94.5% (95% CI 92.5, 96.1) of the patients achieved virological suppression below 400 copies/ml after a median (IQR) of 26 (17-35) months on cART. When patients who were lost to follow-up, dead or stopped were assumed to have had detectable viraemia, the proportion of patients with virological suppression <400 copies/ml decreased to 74.6% (95% CI 71.5%, 77.4%). Younger age, lower educational status, <95% medication adherence, lower CD4(+) T-cell count at cART initiation and/or the diagnosis of immunological failure thereafter significantly predicted detectable viraemia.

CONCLUSIONS

Virological suppression levels can be high in an established ART programme in a resource-limited setting, even without the availability of routine pVL monitoring. Efforts to improve treatment outcomes should focus on younger and illiterate patients, earlier detection of HIV-positive status and cART initiation before patients are severely immunocompromised, and improving retention in care.

Patterns of HIV-1 Drug-Resistance Mutations among Patients Failing First-Line Antiretroviral Treatment in South India

BACKGROUND

Although highly active antiretroviral therapy has improved the quality of life among HIV-infected people in India, the emergence of drug resistance along with the limited access and affordability to routine monitoring continues to be a challenge worldwide.

METHODS

The frequency and patterns of HIV-1 drug-resistance mutations among the first-line failing HIV-infected patients attending a hospital in Salem, Tamil Nadu, India, were genotypically analyzed using the online Stanford HIV Database.

RESULTS

Of the study patients followed up for 6 months, 23 patients failed first-line therapy and the mutation of I135R/T/V/X, L178 I/M, M184V/I, D67N, K70R, and K103N was most common. Phylogenetic analysis revealed that most of these patients belonged to HIV subtype C.

CONCLUSION

The study documents the frequency of nucleoside reverse transcriptase inhibitor and nonnucleoside reverse transcriptase inhibitor mutations that are prevalent in the first-line failing HIV-infected patients of South Indian region and adds up to the data for developing future algorithms to study the drug-resistance mutations of HIV subtype C. Thus, the results of the study call for the need for rational approach for selecting and for frequent viral monitoring to be performed to detect failure, followed by genotyping.

Clinical Applications of Quantitative Real-Time PCR in Virology

Since the invention of the polymerase chain reaction (PCR) and discovery of Taq polymerase, PCR has become a staple in both research and clinical molecular laboratories. As clinical and diagnostic needs have evolved over the last few decades, demanding greater levels of sensitivity and accuracy, so too has PCR performance. Through optimisation, the present-day uses of real-time PCR and quantitative real-time PCR are enumerable. The technique, combined with adoption of automated processes and reduced sample volume requirements, makes it an ideal method in a broad range of clinical applications, especially in virology. Complementing serologic testing by detecting infections within the pre-seroconversion window period and infections with immunovariant viruses, real-time PCR provides a highly valuable tool for screening, diagnosing, or monitoring diseases, as well as evaluating medical and therapeutic decision points that allows for more timely predictions of therapeutic failures than traditional methods and, lastly, assessing cure rates following targeted therapies. All of these serve vital roles in the continuum of care to enhance patient management. Beyond this, quantitative real-time PCR facilitates advancements in the quality of diagnostics by driving consensus management guidelines following standardisation to improve patient outcomes, pushing for disease eradication with assays offering progressively lower limits of detection, and rapidly meeting medical needs in cases of emerging epidemic crises involving new pathogens that may result in significant health threats.

The effect of sexually transmitted co-infections on HIV viral load amongst individuals on antiretroviral therapy: a systematic review and meta-analysis

Background

Antiretroviral therapy (ART) markedly reduces HIV transmission, and testing and treatment programs have been advocated as a method for decreasing transmission at the population level. Little is known, however, about the extent to which sexually transmitted infections (STIs), which increase the HIV infectiousness of untreated individuals, may decrease the effectiveness of treatment as prevention.

Methods

We searched major bibliographic databases to August 12^th, 2014 and identified studies reporting differences in HIV transmission rate or in viral load between individuals on ART who either were or were not co-infected with another STI. We used hierarchical Bayesian models to estimate viral load differences between individuals with and without STI co-infections.

Results

The search strategy retrieved 1630 unique citations of which 14 studies (reporting on 4607 HIV viral load measurements from 2835 unique individuals) met the inclusion criteria. We did not find any suitable studies that estimated transmission rates directly in both groups. Our meta-analysis of HIV viral load measurements among treated individuals did not find a statistically significant effect of STI co-infection; viral loads were, on average, 0.11 log10 (95 % CI −0.62 to 0.83) higher among co-infected versus non-co-infected individuals.

Conclusions

Direct evidence about the effects of STI co-infection on transmission from individuals on ART is very limited. Available data suggests that the average effect of STI co-infection on HIV viral load in individuals on ART is less than 1 log10 difference, and thus unlikely to decrease the effectiveness of treatment as prevention. However, there is not enough data to rule out the possibility that particular STIs pose a larger threat.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-0961-5) contains supplementary material, which is available to authorized users.

Cocaine promotes both initiation and elongation phase of HIV-1 transcription by activating NF-κB and MSK1 and inducing selective epigenetic modifications at HIV-1 LTR

Cocaine accelerates human immunodeficiency virus (HIV-1) replication by altering specific cell-signaling and epigenetic pathways. We have elucidated the underlying molecular mechanisms through which cocaine exerts its effect in myeloid cells, a major target of HIV-1 in central nervous system (CNS). We demonstrate that cocaine treatment promotes HIV-1 gene expression by activating both nuclear factor-kappa B (NF-ĸB) and mitogen- and stress-activated kinase 1 (MSK1). MSK1 subsequently catalyzes the phosphorylation of histone H3 at serine 10, and p65 subunit of NF-ĸB at 276th serine residue. These modifications enhance the interaction of NF-ĸB with P300 and promote the recruitment of the positive transcription elongation factor b (P-TEFb) to the HIV-1 LTR, supporting the development of an open/relaxed chromatin configuration, and facilitating the initiation and elongation phases of HIV-1 transcription. Results are also confirmed in primary monocyte derived macrophages (MDM). Overall, our study provides detailed insights into cocaine-driven HIV-1 transcription and replication.

[GESIDA/National AIDS Plan: Consensus document on antiretroviral therapy in adults infected by the human immunodeficiency virus (Updated January 2015)]

OBJECTIVE

This consensus document is an update of combined antiretroviral therapy (cART) guidelines and recommendations for HIV-1 infected adult patients.

METHODS

To formulate these recommendations, a panel composed of members of the AIDS Study Group and the AIDS National Plan (GeSIDA/Plan Nacional sobre el Sida) reviewed the efficacy and safety advances in clinical trials, and cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. The strength of the recommendations, and the evidence that supports them, are based on modified criteria of the Infectious Diseases Society of America.

RESULTS

In this update, cART is recommended for all patients infected by type 1 human immunodeficiency virus (HIV-1). The strength and level of the recommendation depends on the CD4+T-lymphocyte count, the presence of opportunistic diseases or comorbid conditions, age, and prevention of transmission of HIV. The objective of cART is to achieve an undetectable plasma viral load. Initial cART should always comprise a combination of 3 drugs, including 2 nucleoside reverse transcriptase inhibitors, and a third drug from a different family. Three out of the ten recommended regimes are regarded as preferential (all of them with an integrase inhibitor as the third drug), and the other seven (based on a non-nucleoside reverse transcriptase inhibitor, a ritonavir-boosted protease inhibitor, or an integrase inhibitor) as alternatives. This update presents the causes and criteria for switching cART in patients with undetectable plasma viral load, and in cases of virological failure where rescue cART should comprise 3 (or at least 2) drugs that are fully active against the virus. An update is also provided for the specific criteria for cART in special situations (acute infection, HIV-2 infection, and pregnancy) and with comorbid conditions (tuberculosis or other opportunistic infections, kidney disease, liver disease, and cancer).

CONCLUSIONS

These new guidelines update previous recommendations related to cART (when to begin and what drugs should be used), how to monitor and what to do in case of viral failure or drug adverse reactions. cART specific criteria in comorbid patients and special situations are equally updated.

Factors associated with virological failure and suppression after enhanced adherence counselling, in children, adolescents and adults on antiretroviral therapy for HIV in Swaziland

INTRODUCTION

This study explores factors associated with virological detectability, and viral re-suppression after enhanced adherence counselling, in adults and children on antiretroviral therapy (ART) in Swaziland.

METHODS

This descriptive study used laboratory data from 7/5/2012 to 30/9/2013, which were linked with the national ART database to provide information on time on ART and CD4 count; information on enhanced adherence counselling was obtained from file review in health facilities. Multivariable logistic regression was used to explore the relationship between viral load, gender, age, time on ART, CD4 count and receiving (or not receiving) enhanced adherence counselling.

RESULTS

From 12,063 patients undergoing routine viral load monitoring, 1941 (16%) had detectable viral loads. Children were more likely to have detectable viral loads (AOR 2.6, 95%CI 1.5-4.5), as were adolescents (AOR 3.2, 95%CI 2.2-4.8), patients with last CD4<350 cells/µl (AOR 2.2, 95%CI 1.7-2.9) or WHO Stage 3/4 disease (AOR 1.3, 95%CI 1.1-1.6), and patients on ART for longer (AOR 1.1, 95%CI 1.1-1.2). At retesting, 450 (54% of those tested) showed viral re-suppression. Children were less likely to re-suppress (AOR 0.2, 95%CI 0.1-0.7), as were adolescents (AOR 0.3, 95%CI 0.2-0.8), those with initial viral load> 1000 copies/ml (AOR 0.3, 95%CI 0.1-0.7), and those with last CD4<350 cells/µl (AOR 0.4, 95%CI 0.2-0.7). Receiving (or not receiving) enhanced adherence counselling was not associated with likelihood of re-suppression.

CONCLUSIONS

Children, adolescents and those with advanced disease were most likely to have high viral loads and least likely to achieve viral suppression at retesting; receiving adherence counselling was not associated with higher likelihood of viral suppression. Although the level of viral resistance was not quantified, this study suggests the need for ART treatment support that addresses the adherence problems of younger people; and to define the elements of optimal enhanced adherence support for patients of all ages with detectable viral loads.

Stochastic modelling of viral blips in HIV-1-infected patients: effects of inhomogeneous density fluctuations

We propose a stochastic model of HIV-1 infection dynamics under HAART in order to analyse the origin and dynamics of the so-called viral blips, i.e. episodes of transient viremia that occur in the phase of where the disease remains in a latent state during which the viral load raises above the detection limit of standard clinical assays. Based on prior work in the subject, we consider an infection model in which latently infected cell compartment sustains a residual (latent) infection over long periods of time. Unlike previous models, we include the effects of inhomogeneities in cell and virus concentration in the blood stream. We further consider the effect of burst virion production. By comparing with the experimental results obtained during a study in which intensive sampling was carried out on HIV-1-infected patients undergoing HAART over a long period of time, we conclude that our model supports the hypothesis that viral blips are consistent with random fluctuations around the average viral load. We further observe that agreement between our simulation results and the blip statistics obtained in the aforementioned study improves when burst virion production is considered. We also study the effect of sample manipulation artifacts on the results produced by our model, in particular, that of the post-extraction handling time, i.e. the time elapsed between sample extraction and actual test. Our results support the notion that the statistics of viral blips can be critically affected by such artifacts.

Influence of treatment complexity on adherence and incidence of blips in HIV/HCV coinfected patients

BACKGROUND

The addition of antihepatitis C therapy to highly active antiretroviral treatment (HAART) in human immunodeficiency virus (HIV)/hepatitis C virus (HCV) coinfected patients leads to an increase in the treatment complexity that may result in decreased adherence. Blips, defined as intermittent episodes of detectable low-level HIV viremia, may be an indication of poor adherence to HAART.

OBJECTIVES

To (a) determine the influence of adding anti-HCV therapy to HAART on complexity index, adherence, and incidence of blips and (b) determine complexity index and adherence in patient subgroups based on anti-HCV therapy.

METHODS

We conducted a prospective 2-center observational study. HIV/HCV coinfected patients under antiretroviral treatment who started anti-HCV bi-therapy or triple therapy between January 2011 and December 2013 were included. Patients were excluded if they were virologically uncontrolled (HIV viral load greater than 50 copies RNA/mL) or if they had changed antiretroviral treatment in the 6 months prior to the introduction of anti-HCV therapy. Data were collected before and after the addition of anti-HCV therapy to HAART. The main variables were complexity index, incidence of blips, and adherence. The complexity index was based on a score that utilized the number of pills per day, dosing schedule, dosage form, and any specific instructions linked to use of the drug. Blips were defined as a detectable HIV-RNA level ( greater than 50 copies/mL but no more than 1,000 copies/mL) occurring between 2 negative assays. Medication adherence was assessed using electronic pharmacy refill records. The threshold for optimal adherence was defined at 95% and above. Differences in the variables collected were assessed before and after the addition of anti-HCV therapy to HAART.R ESULTS: A total of 66 patients were included in the study. Based on the complexity index, the median value before and after the addition of anti-HCV therapy to HAART was 4.2 (interquartile range [IQR] = 3.5-5.5) and 11.5 (IQR = 10.4-13.4), respectively. The median difference between both complexity indices was 6.9 (95% CI = 6.9-7, P  less than  0.001). After introducing the anti-HCV therapy into HAART, the number of adherent patients decreased from 50 (75.8%) to 45 (68.2%, P  greater than 0.05), and 12 (18.2%) patients presented blips (P  less than  0.001). Subgroup analysis based on anti-HCV therapy showed that patients on boceprevir or telaprevir therapy had a higher complexity index, 16.8 (IQR = 6.0-18.4), compared with patients on bi-therapy anti-HCV, 11.3 (IQR = 10.3-12). The median difference was 6.0 (95% CI = 5.0-7.2, P  less than  0.001). The number of adherent patients decreased only in patients on bi-therapy from 42 (79.2%) to 37 (69.8%, P  greater than 0.05).

CONCLUSIONS

Adding anti-HCV therapy to antiretroviral treatment significantly increases treatment complexity and the incidence of blips. The introduction of anti-HCV therapy is also associated with a decrease in the number of adherent patients. The regimen complexity calculation may be useful for identifying patients who need more care from health care professionals or are at risk for failure to comply with treatment regimens.

HIV type 1 drug resistance patterns among patients failing first and second line antiretroviral therapy in Nairobi, Kenya

BACKGROUND

The ever-expanding rollout of antiretroviral therapy in poor resource settings without routine virological monitoring has been accompanied with development of drug resistance that has resulted in limited treatment success.

METHODS

A cross-sectional study with one time viral load was conducted during the period between 2012 and 2013 to determine treatment failure and drug resistance mutations among adults receiving first-line (44) (3TC_d4T/AZT_NVP/EFV) and second-line (20) (3TC/AZT/LPV/r) in Nairobi, Kenya. HIV-1 pol-RT genotyping for drug resistance was performed using an in-house protocol.

RESULTS

A total of 64 patients were recruited (mean age 36.9 yrs.) during the period between 2012 and 2013 of the 44 adult patients failing first-line 24 (40.9%) had drug resistance mutations. Eight (8) patients had NRTI resistance mutations with NAMS M184V (54.2%) and K65R (8.4%) mutations being the highest followed by TAMs T215Y and K70R (12.5%). In addition, among patients failing second-line (20), six patients (30%) had NNRTI resistance; two patients on K103N and G190A mutations while V106A, Y184V, A98G, Y181C mutations per patient were also detected. However, for NRTI two patients had TAM T215Y. M184V mutation occurred in one patient.

CONCLUSIONS

The study findings showed that HIV-1 drug resistance was significantly high in the study population. The detected accumulated resistance strains show that emergence of HIV drug resistance will continue to be a big challenge and should be given more attention as the scale up of treatment in the country continues.

Residual viremia is preceding viral blips and persistent low-level viremia in treated HIV-1 patients

BACKGROUND

It has been suggested that low-level viremia or blips in HIV-infected patients on antiretroviral treatment are related to assay variation and/or increased sensitivity of new commercial assays. The 50-copy cut-off for virologic failure is, therefore, under debate.

METHODS

Treated patients with low-level viremia (persistent viral loads (VL) of 50-1000 copies/mL, group A, N = 16) or a blip (single detectable VL, group B, N = 77) were compared to a control group (consistently suppressed viremia since start therapy (<50 copies/mL), N = 79). Residual viremia (detectable viral RNA <50 copies/ml) in the year preceding the first VL above 50 copies/mL (T0) was determined using Roche Cobas-Amplicor v1.5 or CAP-CTM v2.0. Subsequent virologic failure (2 consecutive VLs>500 or 1 VL>1000 copies/mL that was not followed by a VL<50 copies/mL; median follow up 34 months) was assessed.

RESULTS

Significantly more patients in groups A and B had residual viremia in the year preceding T0 compared to controls (50% and 19% vs 3% respectively; p<0.001). Residual viremia was associated with development of low-level viremia or blips (OR 10.9 (95% CI 2.9-40.6)). Subsequent virologic failure was seen more often in group A (3/16) and B (2/77) than in the control group (0/79).

CONCLUSION

Residual viremia is associated with development of blips and low-level viremia. Virologic failure occurred more often in patients with low-level viremia. These results suggest that low-level viremia results from viral production/replication rather than only assay variation.

Association between first-year virological response to raltegravir and long-term outcomes in treatment-experienced patients with HIV-1 infection

BACKGROUND

We explored the relationship between virological response in the first year of treatment and long-term outcomes in the BENCHMRK studies.

METHODS

Patients failing antiretroviral treatment with 3-class resistant HIV-1 received double-blinded raltegravir (or placebo) with optimized background therapy (OBT) until week 156, followed by open-label raltegravir with OBT up to week 240. In this exploratory analysis of patients randomized to raltegravir, virological response over weeks 16-48 was categorized as continuous suppression (CS; viral RNA [vRNA] always <50 copies/ml), low-level viraemia (LLV; vRNA always <400 copies/ml, >50 copies/ml at least once), or not suppressed (NS; vRNA >400 copies/ml at least once). The association between these first-year vRNA response categories and baseline factors was analysed with univariate and multivariate models. Virological and immunological outcomes for years 2-5 were assessed by first-year vRNA response category (observed failure approach).

RESULTS

Baseline vRNA, baseline CD4(+) T-cell count and rapid viral decay (vRNA <50 copies/ml between weeks 2-12) correlated with first-year vRNA response (P<0.001); only rapid viral decay remained significant by multiple regression. Virological response rates were similar in the LLV and CS groups and lowest in the NS group. CD4(+) T-cell count increased through week 240 in the CS and LLV groups. Time to loss of virological response (confirmed vRNA ≥400 copies/ml) through week 240 did not support as strong a difference between the LLV and CS groups (log-rank P=0.11) as previously reported through weeks 156 and 192 (P<0.05).

CONCLUSIONS

Treatment-experienced patients on a raltegravir-based regimen with early LLV may have long-term virological and immunological benefit when their therapy is maintained.

SAMBA HIV semiquantitative test, a new point-of-care viral-load-monitoring assay for resource-limited settings

Routine viral-load (VL) testing of HIV-infected individuals on antiretroviral therapy (ART) is used to monitor treatment efficacy. However, due to logistical challenges, implementation of VL has been difficult in resource-limited settings. The aim of this study was to evaluate the performance of the SAMBA semi-Q (simple amplification-based assay semiquantitative test for HIV-1) in London, Malawi, and Uganda. The SAMBA semi-Q can distinguish between patients with VLs above and below 1,000 copies/ml. The SAMBA semi-Q was validated with diluted clinical samples and blinded plasma samples collected from HIV-1-positive individuals. SAMBA semi-Q results were compared with results from the Roche COBAS AmpliPrep/COBAS TaqMan HIV-1 test, v2.0. Testing of 96 2- to 10-fold dilutions of four samples containing HIV-1 subtype C as well as 488 samples from patients in the United Kingdom, Malawi, and Uganda yielded an overall accuracy for the SAMBA semi-Q of 99% (95% confidence interval [CI], 93.8 to 99.9%) and 96.9% (95% CI 94.9 to 98.3%), respectively, compared to to the Roche test. Analysis of VL data from patients in Malawi and Uganda showed that the SAMBA cutoff of 1,000 copies/ml appropriately distinguished treated from untreated individuals. Furthermore, analysis of the viral loads of 232 patients on ART in Malawi and Uganda revealed similar patterns for virological control, defined as either <1,000 copies/ml (SAMBA cutoff) or <5,000 copies/ml (WHO 2010 criterion; WHO, Antiretroviral Therapy for HIV Infection in Adults and Adolescents: Recommendations for a Public Health Approach, 2010). This study suggests that the SAMBA semi-Q has adequate concurrency with the gold standard measurements for viral load. This test can allow VL monitoring of patients on ART at the point of care in resource-limited settings.

Stochastic population switch may explain the latent reservoir stability and intermittent viral blips in HIV patients on suppressive therapy

Highly active antiretroviral therapy can suppress plasma viral loads of HIV-1 infected individuals to below the detection limit of standard clinical assays. However, low-level viremia still persists. Many patients also have transient viral load measurements above the detection limit (the so-called "viral blips"). The latent reservoir consisting of latently infected CD4+ T cells represents a major obstacle to HIV-1 eradication. These cells can be activated to produce virions but the size of the latent reservoir is relatively stable. The mechanisms underlying low viral load persistence, emergence of intermittent viral blips and stability of the latent reservoir are not well understood. Cellular and viral transcription factors play an important role in the establishment and maintenance of HIV-1 latency. Infected cells with intermediate transcriptional activities may either revert to a latent state or become highly activated and produce virions due to intracellular perturbations. Here we develop a mathematical model that includes such stochastic population switch. We demonstrate that the model can generate a stable latent reservoir, intermittent viral blips, as well as low-level viremia persistence. Latently infected cells with intermediate transcription activities may maintain their size through a high level of homeostatic proliferation, while cells with low transcriptional activities are likely to be maintained through the reversion from cells with intermediate transcription activities. Simulations also suggest that treatment intensification or activation therapy may not help to eradicate the latent reservoir. Blocking the proliferation of latently infected cells might be a good strategy. These results provide more insights into the long-term dynamics of virus and latently infected cells in HIV patients on suppressive therapy and may help to develop novel treatment strategies.

[GeSIDA/National AIDS Plan: Consensus document on antiretroviral therapy in adults infected by the human immunodeficiency virus (Updated January 2014)]

OBJECTIVE

This consensus document is an update of combined antiretroviral therapy (cART) guidelines for HIV-1 infected adult patients.

METHODS

To formulate these recommendations a panel composed of members of the Grupo de Estudio de Sida and the Plan Nacional sobre el Sida reviewed the efficacy and safety advances in clinical trials, cohort and pharmacokinetic studies published in medical journals (PubMed and Embase) or presented in medical scientific meetings. Recommendations strength and the evidence in which they are supported are based on modified criteria of the Infectious Diseases Society of America.

RESULTS

In this update, antiretroviral therapy (ART) is recommended for all patients infected by type 1 human immunodeficiency virus (HIV-1). The strength and grade of the recommendation varies with the clinical circumstances: CDC stage B or C disease (A-I), asymptomatic patients (depending on the CD4+ T-lymphocyte count: <350cells/μL, A-I; 350-500 cells/μL, A-II, and >500 cells/μL, B-III), comorbid conditions (HIV nephropathy, chronic hepatitis caused by HBV or HCV, age >55years, high cardiovascular risk, neurocognitive disorders, and cancer, A-II), and prevention of transmission of HIV (mother-to-child or heterosexual, A-I; men who have sex with men, A-III). The objective of ART is to achieve an undetectable plasma viral load. Initial ART should always comprise a combination of 3 drugs, including 2 nucleoside reverse transcriptase inhibitors and a third drug from a different family (non-nucleoside reverse transcriptase inhibitor, protease inhibitor, or integrase inhibitor). Some of the possible initial regimens have been considered alternatives. This update presents the causes and criteria for switching ART in patients with undetectable plasma viral load and in cases of virological failure where rescue ART should comprise 2 or 3 drugs that are fully active against the virus. An update is also provided for the specific criteria for ART in special situations (acute infection, HIV-2 infection, and pregnancy) and with comorbid conditions (tuberculosis or other opportunistic infections, kidney disease, liver disease, and cancer).

CONCLUSIONS

These new guidelines updates previous recommendations related to cART (when to begin and what drugs should be used), how to monitor and what to do in case of viral failure or drug adverse reactions. cART specific criteria in comorbid patients and special situations are equally updated.

French 2013 guidelines for antiretroviral therapy of HIV-1 infection in adults

Introduction

These guidelines are part of the French Experts’ recommendations for the management of people living with HIV/AIDS, which were made public and submitted to the French health authorities in September 2013. The objective was to provide updated recommendations for antiretroviral treatment (ART) of HIV-positive adults. Guidelines included the following topics: when to start, what to start, specific situations for the choice of the first session of antiretroviral therapy, optimization of antiretroviral therapy after virologic suppression, and management of virologic failure.

Methods

Ten members of the French HIV 2013 expert group were responsible for guidelines on ART. They systematically reviewed the most recent literature. The chairman of the subgroup was responsible for drafting the guidelines, which were subsequently discussed within, and finalized by the whole expert group to obtain a consensus. Recommendations were graded for strength and level of evidence using predefined criteria. Economic considerations were part of the decision-making process for selecting preferred first-line options. Potential conflicts of interest were actively managed throughout the whole process.

Results

ART should be initiated in any HIV-positive person, whatever his/her CD4 T-cell count, even when >500/mm³. The level of evidence of the individual benefit of ART in terms of mortality or progression to AIDS increases with decreasing CD4 cell count. Preferred initial regimens include two nucleoside reverse transcriptase inhibitors (tenofovir/emtricitabine or abacavir/lamivudine) plus a non-nucleoside reverse transcriptase inhibitor (efavirenz or rilpivirine), or a ritonavir-boosted protease inhibitor (atazanavir or darunavir). Raltegravir, lopinavir/r, and nevirapine are recommended as alternative third agents, with specific indications and restrictions. Specific situations such as HIV infection in women, primary HIV infection, severe immune suppression with or without identified opportunistic infection, and person who injects drugs are addressed. Options for optimization of ART once virologic suppression is achieved are discussed. Evaluation and management of virologic failure are described, the aim of any intervention in such situation being to reduce plasma viral load to <50 copies/ml.

Conclusion

These guidelines recommend that any HIV-positive individual should be treated with ART. This recommendation was issued both for the patient’s own sake and for promoting treatment as prevention.

HIV-1 drug resistance and associated factors among adults failing first-line highly active antiretroviral therapy in Ho Chi Minh City, Vietnam

BACKGROUND & OBJECTIVES

Little is known about HIV-1 drug resistance (HIVDR) in people failing first-line highly active antiretroviral therapy (HAART) in Vietnam. The aim of this study was to investigate the frequency of HIV-1 drug resistance mutations (DRMs) and determine correlates of acquiring genotypic HIVDR among Vietnamese adults (age ≥ 18) who met the immunological or clinical criteria of first-line HAART failure according to the guidelines of the World Health Organization (WHO).

METHODS

A total of 138 individuals participated in a descriptive study in Ho Chi Minh City between 2006 and 2009. Blood samples were collected for performing HIV-1 viral load (VL) and genotyping for specimens with VL ≥ 1,000 copies/mL. Stanford algorithm was used to interpret DRMs and multivariate analyses were performed to investigate predictors of HIVDR acquisition.

RESULTS

Of the study population, most participants failed either stavudine/lamivudine/nevirapine or stavudine/lamivudine/efavirenz (116 individuals). Up to 51 people obtained a VL <1,000 copies/mL. Among 87 participating individuals with VL ≥1,000 copies/mL, 11 people still harbored a wild-type strain, while 76 participants harbored a HIV-1 drug-resistant strain (2 of which were against protease inhibitors); common DRMs were M184I/V (74%), Y181I/C/V (39%), G190A/S (32%), T215Y/F (32%), and K103N (31%). The proportions of K65R, Q151M, and T69 insertion were 13%, 11%, and 5%, respectively. Being antiretroviral-exposed before initiating first-line HAART in a public and free-of-charge outpatient clinic, having nonadherence to first-line HAART, per 12-month increase of duration on first-line HAART, and having clinical failure criteria were significantly associated with a genotypic HIVDR acquisition.

CONCLUSIONS

In the absence of VL for the population with WHO immunological/ clinical treatment failure criteria, a large proportion of people still achieved a VL <1,000 copies/mL, while a high prevalence of HIVDR was observed in those with VL ≥1,000 copies/mL. Thus, VL monitoring should be implemented now for the HAART-treated population in Vietnam.

Emergence of drug resistance in human immunodeficiency virus type 1 infected patients from pune, India, at the end of 12 months of first line antiretroviral therapy initiation

Introduction. In India, 4,86,173 HIV infected patients are on first line antiretroviral therapy (ART) as of January 2012. HIV drug resistance (HIVDR) is drug and regimen-specific and should be balanced against the benefits of providing a given ART regimen. Material & Methods. The emergence of HIVDR mutations in a cohort of 100 consecutive HIV-1 infected individuals attending ART centre, on first line ART for 12 months, was studied. CD4(+) T-cell counts and plasma HIV-1 RNA level were determined. Result. Out of the 100 HIV-1 infected individuals, 81 showed HIVDR prevention (HIV-1 RNA level < 1000/mL), while the remaining 19 had HIV-1 viral RNA level > 1000/mL. HIVDR genotyping was carried out for individuals with evidence of virologic failure (HIV-1 RNA level > 1000/mL). The most frequent NRTI-associated mutation observed was M184V, while K103N/S was the commonest mutation at NNRTI resistance position. Conclusion. Our study has revealed the emergence of HIVDR in HIV-1 infected patients at the end of 12 months of first line ART initiation. For NRTIs, the prevalence of HIVDR mutations was 9% and 10% for NNRTIs. Our findings will contribute information in evidence-based decision making with reference to first and second line ART delivery and prevention of HIVDR emergence.

Clinical evaluation of a low cost, in-house developed real-time RT-PCR human immunodeficiency virus type 1 (HIV-1) quantitation assay for HIV-1 infected patients

OBJECTIVES

HIV-1 viral quantitation is essential for treatment monitoring. An in-house assay would decrease financial barriers to access.

MATERIALS AND METHODS

A real-time competitive RT-PCR in house assay (Sing-IH) was developed in Singapore. Using HXB2 as reference, the assay's primers and probes were designed to generate a 183-bp product that overlaps a portion of the LTR region and gag region. A competitive internal control (IC) was included in each assay to monitor false negative results due to inhibition or human error. Clinical evaluation was performed on 249 HIV-1 positive patient samples in comparison with the commercially available Generic HIV Viral Load assay. Correlation and agreement of results were assessed for plasma HIV-1 quantification with both assays.

RESULTS

The assay has a lower limit of detection equivalent to 126 copies/mL of HIV-1 RNA and a linear range of detection from 100-1000000 copies/mL. Comparative analysis with reference to the Generic assay demonstrated good agreement between both assays with a mean difference of 0.22 log10 copies/mL and 98.8% of values within 1 log10 copies/mL range. Furthermore, the Sing-IH assay can quantify HIV-1 group M subtypes A-H and group N isolates adequately, making it highly suitable for our region, where subtype B and CRF01_AE predominate.

CONCLUSIONS

With a significantly lower running cost compared to commercially available assays, the broadly sensitive Sing-IH assay could help to overcome the cost barriers and serve as a useful addition to the currently limited HIV viral load assay options for resource-limited settings.