Transient Viremia in HIV-Infected Patients and Use of Plasma Preparation Tubes

HIV-1 Genotypic Resistance Testing Using Sanger and Next-Generation Sequencing in Adults with Low-Level Viremia in China

OBJECTIVE

In this study, we aimed to determine drug-resistance mutations (DRMs) in HIV-1 patients with low-level viremia (LLV) and explored the performance of next-generation sequencing (NGS) in detecting HIV DRMs by using LLV samples.

METHODS

Overall, 80 samples with LLV were amplified and sequenced using a commercial Sanger sequencing (SS) genotyping kit. Furthermore, 51 samples successfully sequenced using SS were simultaneously subjected to NGS. Genotyping success rates of various viremia categories by two sequencing methods were calculated. Stanford HIV-1 drug-resistance database (HIVdb version 8.9) was used to analyze the DRMs. In the NGS assay, a threshold of 5% was considered for reporting low-frequency variants, and the DRMs detected using SS and NGS were compared.

RESULTS

The overall success rate of PR/RT regions was 88.1% (67/80) using SS and 86.3% (44/51) using NGS. Furthermore, a significant linear trend was noted between viral load and the genotyping success rate. A total of 38.8% (26/67) participants harbored at least one mutation, as revealed through SS. Moreover, the prevalence of DRMs in persistent LLV was significantly higher than that in intermittent LLV (62.1% vs. 21.1%; P < 0.05). A total of 69 DRMs were detected using the two sequencing methods at the threshold of 5%. Moreover, 10 DRMs missed by SS were detected using NGS, whereas 8 DRMs missed by NGS were detected by SS.

CONCLUSION

Our data suggested that the genotyping resistance testing is necessary to guide antiretroviral therapy optimization in LLV patients.

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.

Persistent Low-Level Viremia is an Independent Risk Factor for Virologic Failure: A Retrospective Cohort Study in China

Background

Whether intermittent low-level viremia (iLLV/blip) or persistent low-level viremia (pLLV) increases the risk of virologic failure (VF) in HIV-1 patients is controversial. The objective of this study was to investigate the incidence of blip/pLLV and the association between blip/pLLV and VF in a Chinese antiretroviral therapy cohort.

Methods

HIV-1 patients who underwent antiretroviral therapy (ART) from 2005 to 2018 and had at least two viral load (VL) measurements after a minimum of 6 months ART treatment were included. VF was defined as one or more VL measurements of ≥1000 copies/mL. Blip was described as an isolated VL measurement between 50 and 999 copies/mL, and pLLV was defined as two or more consecutive VL measurements between 50 and 999 copies/mL. Blip and pLLV were categorized separately into three groups: 50–200, 201–400 and 401–999 copies/mL. The Cox proportional hazard model was used to explore the association between blip/pLLV and VF.

Results

In total, 8098 participants were enrolled in this long-term cohort study. A 94.3% of the participants were male and among which 77.3% were infected through homosexual transmission. Blip occurred in 4.0% (325/8098) of the patients with an incidence of 0.73 per 100 person-years (/100 PYS) of follow-up (95% CI: 0.71–0.76), whereas pLLV occurred in 1.3% of the patients (102/8098) with an incidence of 0.23/100 PYS of follow-up (95% CI: 0.21–0.25). All the three categories of pLLV were associated with VF: pLLV 50–200 [aHR: 3.82 (1.95–7.47)], pLLV 201–400 [aHR: 5.36 (2.35–12.22)] and pLLV 401–999 [aHR: 13.51 (8.28–22.02)]. However, blip is not significantly associated with VF in any category.

Conclusion

Our study suggested that patients with pLLV had an increased risk of subsequent VF. Therefore, if pLLV occurs in patients, monitoring and corresponding measurements must be strengthened to avoid the subsequent VF.

HIV-1 viral load testing in resource-limited settings: Challenges and solutions for specimen integrity

HIV-1 viral load (VL) testing is a crucial element in providing an antiretroviral treatment monitoring program. The success of these programs depends on the availability and quality of the VL testing services. There are several pre-analytic factors which can affect the quality of VL testing. Many of the challenges faced by resource-limited countries result in a compromise of specimen integrity, thus limiting widespread access to VL monitoring. The various logistic and financial challenges that exist are not insurmountable and several innovative solutions currently exist to overcome these barriers to providing widespread VL testing. This review summarizes the VL testing challenges in resource-limited settings and provides an overview of potential solutions including testing dried blood spots, dried plasma spots, plasma separation cards and the use of point of care tests.

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.

Low-level viremia and virologic failure in persons with HIV infection treated with antiretroviral therapy

BACKGROUND

The clinical management of low-level viremia (LLV) remains unclear. The objective of this study was to investigate the association of blips and LLV with virologic failure.

METHODS

We enlisted patients who newly enrolled into the HIV Research Network between 2005 and 2015, had HIV-1 RNA more than 200 copies/ml, and were either antiretroviral therapy (ART)-naive or ART-experienced and not on ART. Patients were included who achieved virologic suppression (≤50 on two consecutive viral loads) and had at least two viral loads following suppression. Blips and LLV (≥2 consecutive >51 copies/ml) were categorized separately into three categories: no blips/LLV, 51-200, 201-500. Cox proportional hazards regression was used to assess association between rates of blips/LLV and virologic failure (two consecutive >500).

RESULTS

The 2795 patients were mostly male (75.4%), black (50.3%), and MSM (52.9%). Median age was 38 years old (interquartile range 29-48). Most patients (88.8%) were ART-naive at study entry. Overall, 283 (10.1%) patients experienced virologic failure. A total of 152 (5.4%) patients experienced LLV to 51-200 and 110 (3.9%) patients experienced LLV to 201-500. Both LLV 51-200 [adjusted hazard ratio (aHR) 1.83 (1.10,3.04)] and LLV 201-500 [aHR 4.26 (2.65,6.86)] were associated with virologic failure. In sensitivity analysis excluding ART-experienced patients, the association between LLV 51 and 200 and virologic failure was not statistically significant.

CONCLUSION

LLV between 201 and 500 was associated with virologic failure, as was LLV between 51 and 200, particularly among ART-experienced patients. Patients with LLV below the current Department of Health and Human Services threshold for virologic failure (persistent viremia ≥200) may require more intensive monitoring because of increased risk for virologic failure.

Meticulous plasma isolation is essential to avoid false low-level viraemia in Roche Cobas HIV-1 viral load assays

BACKGROUND

Pre-analytical sample processing is often overlooked as a potential cause of inaccurate assay results. Here we demonstrate how plasma, extracted from standard EDTA-containing blood collection tubes, may contain traces of blood cells consequently resulting in a false low-level HIV-1 viral load when using Roche Cobas HIV-1 assays.

METHODS

The presence of human DNA in Roche Cobas 4800 RNA extracts and in RNA extracts from the Abbott HIV-1 RealTime assay was assessed by quantifying the human albumin gene by means of quantitative PCR. RNA was extracted from plasma samples before and after an additional centrifugation and tested for viral load and DNA contamination. The relation between total DNA content and viral load was defined.

RESULTS

Elevated concentrations of genomic DNA were detected in 28 out of 100 Cobas 4800 extracts and were significantly more frequent in samples processed outside of the AIDS Reference Laboratory. An association between genomic DNA presence and spurious low-level viraemia results was demonstrated. Supplementary centrifugation of plasma before RNA extraction eliminated the contamination and the false viraemia.

CONCLUSIONS

Plasma isolated from standard EDTA-containing blood collection tubes may contain traces of HIV DNA leading to false viral load results above the clinical cutoff. Supplementary centrifugation of plasma before viral load analysis may eliminate the occurrence of this spurious low-level viraemia.

Impact of CMV PCR Blips in Recipients of Solid Organ and Hematopoietic Stem Cell Transplantation

Background

Viral blips reflecting polymerase chain reaction (PCR) artefacts or transient low-level replication are well described in the human immunodeficiency virus setting. However, the epidemiology of such blips in transplant recipients screened for cytomegalovirus (CMV) with PCR remains uncertain and was investigated in a cohort of solid organ and hematopoietic stem cell recipients.

Methods

Eligible recipients had known donor/recipient CMV IgG serostatus, and 3 CMV PCRs ≥. The CMV PCR triplicates (3 consecutive CMV PCRs) were defined; the first CMV PCR was always negative, and the time between the second and third samples was 7 days ≤. A positive second but negative third sample represented a blip. Odds ratio (OR) for factors associated with a triplicate being a blip was estimated by binomial regression adjusted for repeated measurements. Whether blips affected the hazard ratio (HR) for subsequent CMV infection was determined with a Cox model.

Results

851 recipients generated 3883 CMV PCR triplicates. The OR of a triplicate representing a blip decreased with increasing viral load of the second sample (vs 273 IU/mL; >273-910 IU/mL: odds ratio [OR], 0.2; 95% confidence interval [CI], 0.1-0.5; >910 IU/mL: OR, 0.08; 95% CI, 0.02-0.2; P ≤ 0.0002) and increased with intermediary-/low-risk serostatus (vs high risk) (OR, 2.8; 95% CI, 1.2-5.5; P = 0.01). Cumulative exposure to DNAemia in the CMV blips greater than 910 IU/mL indicated increased HR of subsequent CMV infection (HR, 4.6; 95% CI, 1.2-17.2; P = 0.02).

Conclusions

Cytomegalovirus blips are frequent; particularly when the viral load of the first positive PCR is < 910 IU/mL, and serostatus risk is intermediary/low. Accumulating blips suggest intermittent low-level replication. If blips are suspected, confirmation of ongoing replication before initiation of treatment is prudent.

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.

Viral blips during suppressive antiretroviral treatment are associated with high baseline HIV-1 RNA levels

Background

Many HIV-1-infected patients on suppressive antiretroviral therapy (ART) have transiently elevated HIV RNA levels. The clinical significance of these viral blips is uncertain. We have determined the incidence of blips and investigated important associations in the Swedish HIV-cohort.

Methods

HIV-1-infected ART naïve adults who commenced ART 2007–2013 were retrospectively included. Viral blips were defined as a transient viral load between 50 and 500 copies/mL Subjects not suppressed after six months on ART were excluded.

Results

Viral blips were found in 76/735 included subjects (10.3 %) and in 90/4449 samples (2.0 %). Median blip viral load was 76 copies/mL (range 56–138). Median follow-up time was 170 weeks (range 97–240). Baseline viral load was higher in subjects with viral blips (median log₁₀ 4.85 copies/mL) compared with subjects without blips (median log₁₀ 4.55 copies/mL) (p < 0.01). There was a significant association between viral blips and risk for subsequent virological failure (p < 0.001).

Conclusions

The Swedish national HIV-cohort has a low incidence of viral blips (10 %). Blips were associated with high baseline viral load and an increased risk of subsequent virological failure.

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.

Low-level HIV-1 viraemia in patients on HAART: risk factors and management in clinical practice

OBJECTIVES

Characterization of the conditions favouring HIV-1 low-level viraemia (LLV) during treatment is required to guide strategies for prevention and cure.

METHODS

The characteristics and treatments of 171 patients experiencing a confirmed LLV of 50-1000 copies/mL (PLLVs) were compared with those of 146 patients with persistently controlled viraemia. We analysed the risk factors for LLV, the parameters affecting the level of viraemia and the presence of resistance-associated mutations (RAMs). We compared outcomes for PLLVs on fully effective HAART as a function of treatment modifications.

RESULTS

LLV was <500 copies/mL in at least 90% of cases. A higher zenith viral load (VL) (5.27 versus 4.91 log10 copies/mL, OR 2.23; P = 0.0003), a shorter time on continuous HAART (4.3 versus 6.8 years, OR 0.88; P = 0.0003) and previously detected RAMs (43% versus 23%, OR 2.42; P = 0.0033) were independent predictors of LLV. NNRTIs were less frequently used in PLLVs and were associated with more stable treatment. The presence of any RAM during LLV was associated with a lower zenith VL and a higher LLV. In the absence of resistance, virological success was achieved in similar proportions of patients with and without treatment modification.

CONCLUSIONS

Viraemia >500 copies/mL should no longer be considered to be LLV. In patients with a high zenith VL, several years on continuous HAART may be required to decrease the HIV reservoir and prevent LLV. Resistance testing is useful to detect RAMs, leading if necessary to treatment modifications. In the absence of resistance, treatment changes seemed dispensable.

Significance and clinical management of persistent low-level viremia and very-low-level viremia in HIV-1-infected patients

A goal of HIV therapy is to sustain suppression of the plasma viral load below the detection limits of clinical assays. However, widely followed treatment guidelines diverge in their interpretation and recommended management of persistent viremia of low magnitude, reflecting the limited evidence base for this common clinical finding. Here, we review the incidence, risk factors, and potential consequences of low-level HIV viremia (LLV; defined in this review as a viremia level of 50 to 500 copies/ml) and very-low-level viremia (VLLV; defined as a viremia level of <50 copies/ml detected by clinical assays that have quantification cutoffs of <50 copies/ml). Using this framework, we discuss practical issues related to the diagnosis and management of patients experiencing persistent LLV and VLLV. Compared to viral suppression at <50 or 40 copies/ml, persistent LLV is associated with increased risk of antiretroviral drug resistance and overt virologic failure. Higher immune activation and HIV transmission may be additional undesirable consequences in this population. It is uncertain whether LLV of <200 copies/ml confers independent risks, as this level of viremia may reflect assay-dependent artifacts or biologically meaningful events during suppression. Resistance genotyping should be considered in patients with persistent LLV when feasible, and treatment should be modified if resistance is detected. There is a dearth of clinical evidence to guide management when genotyping is not feasible. Increased availability of genotypic assays for samples with viral loads of <400 copies/ml is needed.

HIV virological rebounds but not blips predict liver fibrosis progression in antiretroviral-treated HIV/hepatitis C virus-coinfected patients

OBJECTIVES

Antiretroviral interruption is associated with liver fibrosis progression in HIV/hepatitis C virus (HCV) coinfection. It is not known what level of HIV viraemia affects fibrosis progression.

METHODS

We evaluated 288 HIV/HCV-coinfected cohort participants with undetectable HIV RNA (<50 HIV-1 RNA copies/mL) on two consecutive visits while on combination antiretroviral therapy (cART) without fibrosis [aspartate aminotransferase to platelet ratio index (APRI) <1.5], end-stage liver disease or HCV therapy. An HIV blip was defined as a viral load of ≥ 50 and <1000 copies/mL, preceded and followed by undetectable values. HIV rebound was defined as: (i) HIV RNA ≥ 50 copies/mL on two consecutive visits, or (ii) a single HIV RNA measurement ≥ 1000 copies/mL. Multivariate discrete-time proportional hazards models were used to assess the effect of different viraemia levels on liver fibrosis progression (APRI ≥ 1.5).

RESULTS

The mean age of the patients was 45 years, 74% were male, 81% reported a history of injecting drug use, 51% currently used alcohol and the median baseline CD4 count was 440 [interquartile range (IQR) 298, 609] cells/μL. Fifty-seven (20%) participants [12.4/100 person-years (PY); 95% confidence interval (CI) 9.2-15.7/100 PY] progressed to an APRI ≥ 1.5 over a mean 1.1 (IQR 0.6, 2.0) years of follow-up time at risk. Virological rebound [hazard ratio (HR) 2.3; 95% CI 1.1, 4.7] but not blips (HR 0.5; 95% CI 0.2, 1.1) predicted progression to APRI ≥ 1.5. Each additional 1 log10 copies/mL HIV RNA exposure (cumulative) was associated with a 20% increase in the risk of fibrosis progression (HR 1.2; 95% CI 1.0-1.3).

CONCLUSIONS

Liver fibrosis progression was associated with HIV rebound, but not blips, and with increasing cumulative exposure to HIV RNA, highlighting the importance of achieving and maintaining HIV suppression in the setting of HIV/HCV coinfection.

The significance of HIV 'blips' in resource-limited settings: is it the same? analysis of the treat Asia HIV Observational Database (TAHOD) and the Australian HIV Observational Database (AHOD)

Introduction

Magnitude and frequency of HIV viral load blips in resource-limited settings, has not previously been assessed. This study was undertaken in a cohort from a high income country (Australia) known as AHOD (Australian HIV Observational Database) and another cohort from a mixture of Asian countries of varying national income per capita, TAHOD (TREAT Asia HIV Observational Database).

Methods

Blips were defined as detectable VL (≥ 50 copies/mL) preceded and followed by undetectable VL (<50 copies/mL). Virological failure (VF) was defined as two consecutive VL ≥50 copies/ml. Cox proportional hazard models of time to first VF after entry, were developed.

Results

5040 patients (AHOD n = 2597 and TAHOD n = 2521) were included; 910 (18%) of patients experienced blips. 744 (21%) and 166 (11%) of high- and middle/low-income participants, respectively, experienced blips ever. 711 (14%) experienced blips prior to virological failure. 559 (16%) and 152 (10%) of high- and middle/low-income participants, respectively, experienced blips prior to virological failure. VL testing occurred at a median frequency of 175 and 91 days in middle/low- and high-income sites, respectively. Longer time to VF occurred in middle/low income sites, compared with high-income sites (adjusted hazards ratio (AHR) 0.41; p<0.001), adjusted for year of first cART, Hepatitis C co-infection, cART regimen, and prior blips. Prior blips were not a significant predictor of VF in univariate analysis (AHR 0.97, p = 0.82). Differing magnitudes of blips were not significant in univariate analyses as predictors of virological failure (p = 0.360 for blip 50–≤1000, p = 0.309 for blip 50–≤400 and p = 0.300 for blip 50–≤200). 209 of 866 (24%) patients were switched to an alternate regimen in the setting of a blip.

Conclusion

Despite a lower proportion of blips occurring in low/middle-income settings, no significant difference was found between settings. Nonetheless, a substantial number of participants were switched to alternative regimens in the setting of blips.

Cobas ampliprep/cobas TaqMan HIV-1 v2.0 assay: consequences at the cohort level

Background

High-sensitive real-time PCR assays are routinely used to monitor HIV-1 infected subjects. Inter-assay discrepancies have been described at the low viral load (VL) end, where clinical decisions regarding possible virological rebound are based.

Methods

A retrospective study was performed to analyze frequencies of viral blips after transition to the COBAS Ampliprep/COBAS TaqMan v2.0 HIV-1 assay (Taqman v2.0) in patients with prior undetectable VLs as measured with the Roche Cobas Ampliprep Amplicor HIV-1 Monitor Test, v1.5 (Amplicor) and was evaluated in comparison to a group of patients monitored with the Abbott Real-time HIV-1 assay (Abbott RT) during the same period of time.

Results

85 of 373 patients with VLs below the limit of quantification with Amplicor had VLs >50 copies/mL after transition to the TaqMan v2.0 assay. Among these 74.1% had VLs ranging from 50–499 copies/mL, 22.9% had VLs >500 copies/mL. From 22 patients with initial Taqman v2.0 based VLs exceeding 500 copies/mL, 6 patients had VLs <20 copies/mL after novel VL measurement on a next visit. In our control group with VL quantification using the Abbott RT assay, only 1 patient became detectable and showed a VL of <40 copies/mL after new measurement.

Conclusions

Transition to the Taqman v2.0 assay was accompanied by an increase of quantifiable HIV-1 VLs in patients with long term viral suppression under antiretroviral therapy that might be attributed to technical shortcomings of the Taqman v2.0 assay. A high test variability at the low VL end but also beyond was observed, making meaningful clinical interpretation of viral blips derived from different assays difficult.

CD8+ T-cell activation in HIV-1-infected patients experiencing transient low-level viremia during antiretroviral therapy

Transient low-level viremia (TLLV) of 50-400 HIV RNA copies per milliliter is common during antiretroviral therapy, but its pathogenesis, consequences, and optimal management are unclear. Heightened immune activation is associated with detrimental outcomes, including impaired CD4 T-cell reconstitution. Using CD38/HLA-DR expression on CD8 T cells measured in 2 large studies, we determined associations between TLLV and immune activation levels before, during, and after TLLV. We found that TLLV does not significantly change CD8 T-cell activation and that higher CD8 T-cell activation during viral suppression <50 copies per milliliter is associated with a modest increase in the risk of a subsequent TLLV.

A comparison of HAART outcomes between the US military HIV Natural History Study (NHS) and HIV Atlanta Veterans Affairs Cohort Study (HAVACS)

Introduction

The Department of Defense (DoD) and the Department of Veterans Affairs (VA) provide comprehensive HIV treatment and care to their beneficiaries with open access and few costs to the patient. Individuals who receive HIV care in the VA have higher rates of substance abuse, homelessness and unemployment than individuals who receive HIV care in the DoD. A comparison between individuals receiving HIV treatment and care from the DoD and the VA provides an opportunity to explore the impact of individual-level characteristics on clinical outcomes within two healthcare systems that are optimized for clinic retention and medication adherence.

Methods

Data were collected on 1065 patients from the HIV Atlanta VA Cohort Study (HAVACS) and 1199 patients from the US Military HIV Natural History Study (NHS). Patients were eligible if they had an HIV diagnosis and began HAART between January 1, 1996 and June 30, 2010. The analysis examined the survival from HAART initiation to all-cause mortality or an AIDS event.

Results

Although there was substantial between-cohort heterogeneity and the 12-year survival of participants in NHS was significantly higher than in HAVACS in crude analyses, this survival disparity was reduced from 21.5% to 1.6% (mortality only) and 26.8% to 4.1% (combined mortality or AIDS) when controlling for clinical and demographic variables.

Conclusion

We assessed the clinical outcomes for individuals with HIV from two very similar government-sponsored healthcare systems that reduced or eliminated many barriers associated with accessing treatment and care. After controlling for clinical and demographic variables, both 12-year survival and AIDS-free survival rates were similar for the two study cohorts who have open access to care and medication despite dramatic differences in socioeconomic and behavioral characteristics.

Successful use of Plasma Preparation Tubes™ (PPTs) in the COBAS® AmpliPrep/COBAS® TaqMan® HIV-1 test

BACKGROUND

Since switching to the COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HIV-1 Test, v. 1.0 from the Amplicor HIV-1 Monitor Test, v. 1.5, an increase in detectable viral load results was noted. We were concerned that this was due to the use of Plasma Preparation Tubes (PPT) in this test.

OBJECTIVE

To assess the impact of different pre-analytical processing conditions on HIV-1 viral load results on the COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HIV-1 Test.

STUDY DESIGN

Sixty-three HIV-infected patients were consented and had 3 PPTs and 1 K2EDTA drawn for HIV-1 viral load testing. Three methods of PPT processing were compared against the referent K2EDTA tube which was spun at 1100 × g for 20 min, poured off and frozen; PPT1 was refrigerated with an additional centrifugation prior to testing, PPT2 was processed similarly to EDTA, and PPT3 was centrifuged, frozen and centrifuged again prior to testing.

RESULTS

PPT1 and PPT3 yielded results that were most similar to the referent EDTA processing, with a concordance correlation coefficient (CCC) of 0.80 and 0.85, compared to PPT2 with CCC of 0.37. Both PPT1 and PPT3 involved additional centrifugation prior to testing. In 26 patients with residual samples from the PPT2 processing, 9 (34.6%) were found to have the presence of proviral DNA, which likely contributed to the elevated HIV-1 RNA viral loads in these individuals.

CONCLUSION

PPTs can be used in the COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HIV-1 Test with an additional centrifugation in order to avoid misleading elevated HIV-1 RNA viral loads that may change patient management.

Monitoring HIV viral load in resource limited settings: still a matter of debate?

Introduction

Consequences of lack of viral monitoring in predicting the effects of development of HIV drug resistance mutations during HAART in resource-limited settings (RLS) is still a matter of debate.

Design

To assess, among HIV+ patients receiving their first-line HAART, prevalence of virological failure and genotypic resistance mutations pattern in a Médécins Sans Frontières/Ministry of Health programme in Busia District (Kenya).

Methods

Patients with HAART treatment for ≥12 months were eligible for the study and those with HIV-RNA ≥5000 copies/ml underwent genotypic study. Total HIV-1 RNA from Dried Blood Spots was extracted using Nuclisens method.

Results

926 patients were included. Among 274 (29.6%) patients with detectable viral load, 55 (5.9%) experienced treatment failure (viral load >5.000 copies/ml); 61.8% were female and 10 (18.2%) had clinical failure. Median CD4 cell count was 116 cell/mm3 (IQR: 54–189). Median HIV-RNA was 32,000 copies/ml (IQR: 11000–68000). Eighteen out of 55 (33%) samples could be sequenced on PR and RT genes, with resistance associated mutations (RAMs) in 15 out of 18 samples (83%). Among patients carrying RAMs, 12/15 (81%) harboured RAMs associated to thymidine analogues (TAMs). All of them (100%) showed M184V resistance associated mutation to lamivudine as well as NNRTI's RAMS.

Conclusions

Virological failure rate in resource-limited settings are similar to those observed in developed countries. Resistance mutation patterns were concordant with HAART received by failing patients. Long term detectable viral load confers greater probability of developing resistance and as a consequence, making difficult to find out a cost-effective subsequent treatment regimen.

Evaluation of the use of plasma preparation tubes for HIV viral load testing on the COBAS AmpliPrep/COBAS TaqMan HIV-1 version 2.0

HIV viral load monitoring forms an essential part of the management of patients receiving antiretroviral therapy, but transport of samples without loss of RNA integrity may be problematic in resource limited settings. The use of plasma preparation tubes (PPT) which can be centrifuged to separate cellular components before transport may provide a simple and cost-effective alternative to standard EDTA samples. We investigated whether PPT generated reliable results using the COBAS(®) AmpliPrep/COBAS(®) TaqMan(®) HIV-1 test version 2.0 (CAP/CTM HIV-1 v2.0). The mean difference between EDTA and PPT prepared samples (n=261) was acceptable (log 0.04 copies/ml, percentage similarity CV 3.53%). PPT can be used for viral load testing on the CAP/CTM HIV-1 v2.0.

The clinical interpretation of viral blips in HIV patients receiving antiviral treatment: are we ready to infer poor adherence?

OBJECTIVES

Viral blips may be an indication of poor adherence to antiretroviral treatment. This article studies how the variations of the definitions of viral blips and that of the choice of sampling frame in studies investigating viral blips may contribute to the uncertainty of the associations between viral blips and possible causes.

DESIGN

Mathematical modeling study allows us to study the impact of different sampling frames and different definitions of blips upon study results that are usually not feasible in clinical settings.

METHODS

Using a previously published mathematical model, scenarios of different drug adherence levels and viral blips, with different sampling frames, were modeled.

RESULTS

In the case of viral blips as a result of nonadherence to combinational antiretroviral therapy, rather than calculating the incidence of blips directly from the number of blips observed in a given period of time, it is better to report the proportion of observations in a given period of time that are ≥50 copies per milliliter. Therefore, as the denominator, the number of observations in a given period of time is important. However, the proportion of blips is not very informative on the drug adherence level.

CONCLUSIONS

We should standardize definitions of viral blips and the choice of sampling frame and to report the proportion of observations of a given sampling frame in a given period of time that are ≥50 copies per milliliter, so that comparable data can be generated across different populations.

Magnitude of virologic blips is associated with a higher risk for virologic rebound in HIV-infected individuals: a recurrent events analysis

BACKGROUND

The importance of human immunodeficiency virus (HIV) blip magnitude on virologic rebound has been raised in clinical guidelines relating to viral load assays.

METHODS

Antiretroviral-naive individuals initiating combination antiretroviral therapy (cART) after 1 January 2000 and achieving virologic suppression were studied. Negative binomial models were used to identify blip correlates. Recurrent event models were used to determine the association between blips and rebound by incorporating multiple periods of virologic suppression per individual.

RESULTS

3550 participants (82% male; median age, 40 years) were included. In a multivariable negative binomial regression model, the Amplicor assay was associated with a lower blip rate than branched DNA (rate ratio, 0.69; P < .01), controlling for age, sex, region, baseline HIV-1 RNA and CD4 count, AIDS-defining illnesses, year of cART initiation, cART type, and HIV-1 RNA testing frequency. In a multivariable recurrent event model controlling for age, sex, intravenous drug use, cART start year, cART type, assay type, and HIV-1 RNA testing frequency, blips of 500-999 copies/mL were associated with virologic rebound (hazard ratio, 2.70; P = .002), whereas blips of 50-499 were not.

CONCLUSIONS

HIV-1 RNA assay was an important determinant of blip rates and should be considered in clinical guidelines. Blips ≥500 copies/mL were associated with increased rebound risk.

Performance of the Abbott RealTime HIV-1 viral load assay is not impacted by integrase inhibitor resistance-associated mutations

The Abbott RealTime HIV-1 viral load assay uses primers and probes targeted to integrase, which is also the target of integrase inhibitors such as raltegravir. Viral loads of 42 raltegravir-susceptible and 40 raltegravir-resistant specimens were determined using RealTime HIV-1 and Roche Monitor (v1.5). The differences in viral load measurements between assays were comparable in the two groups, demonstrating that the RealTime HIV-1 assay can tolerate raltegravir-selected mutations.

Evaluation of effect of specimen-handling parameters for plasma preparation tubes on viral load measurements obtained by using the Abbott RealTime HIV-1 load assay

HIV-1 viral load testing is essential to the management of HIV-1-infected patients, and proper specimen handling ensures accurate viral load (VL) results. This study was performed to (i) evaluate the effect of freezing plasma in situ in BD Vacutainer plasma preparation tubes (PPT) on the accuracy of HIV-1 viral load results using the Abbott RealTime HIV-1 assay and (ii) evaluate the effect of whole-blood storage in the PPT for 6 h at room temperature prior to centrifugation (PPT6H) rather than 2 h as specified in the PPT product insert. Of the 64 HIV-positive subjects evaluated, 29 had average viral load counts of >40 copies/ml in at least one of the tubes tested and 35 subjects had a result of either "undetected target" or "below the limit of quantification" (LOQ) for all or some of the tubes regardless of handling condition. For the 29 subjects with VLs that were >LOQ, the mean biases between plasma from Vacutainer K(2)EDTA tubes and plasma frozen in situ in PPT and between K(2)EDTA tube plasma and plasma from PPT6H (log(10) copies/ml) were 0.005 and -0.001, respectively, and r(2) was >0.92 for all correlations. We conclude that VLs determined from plasma frozen in situ in PPT are equivalent to VLs in K(2)EDTA tube plasma and can be used for accurate quantification of HIV-1 RNA in the Abbott RealTime HIV-1 assay. Furthermore specimens collected in PPT can be stored for 6 h at room temperature with no effect on viral load results as measured by the Abbott RealTime HIV-1 assay.

Coamplification of HIV-1 proviral DNA and viral RNA in assays used for quantification of HIV-1 RNA

Elevated HIV-1 viral load (VL) observed in specimens frozen in situ in plasma preparation tubes (PPTs) compared to EDTA plasma specimens may affect therapeutic monitoring of HIV-infected patients. The increase in viral load is cell associated and minimized when plasma from the PPT is aspirated or recentrifuged prior to freezing. This study investigates the contribution of integrated HIV-1 proviral DNA to elevated VL in the quantification of HIV-1 RNA in plasma. Fifty paired specimens collected in EDTA tubes and PPTs frozen in situ were used for analysis. HIV-1 VL was measured using the COBAS Amplicor Monitor ultrasensitive test version 1.5. Contaminating proviral DNA was detected using a nested PCR targeting the Alu repeat in human genomic DNA and HIV pol gene simultaneously. Treatment of the specimen with DNase resulted in significantly lower quantifiable HIV-1 RNA in specimens from PPTs compared to the corresponding EDTA tubes (P = 0.004). After the RNA was destroyed by heat treatment, the mean HIV-1 RNA VL decreased by 79% in the EDTA tube compared to 65% in the PPT. The nested PCR amplified integrated proviral DNA in nucleic acid extracted from plasma in PPT and EDTA specimens with high viral load values. Likewise, a semiquantitative densitometric analysis revealed that the total amount of genomic DNA in the PPT was higher than that in the EDTA tube. Our investigation clearly shows that both proviral DNA and intracellular RNA are amplified simultaneously in the COBAS Amplicor HIV-1 Monitor assay and that proviral DNA contributes to the elevated VL in plasma frozen in PPTs.

Overestimation of human immunodeficiency virus type 1 load caused by the presence of cells in plasma from plasma preparation tubes

The human immunodeficiency virus type 1 (HIV-1) load is an important marker of disease progression and treatment efficacy in patients with HIV-1 infection. In recent years, an increase in the number of samples with detectable HIV-1 RNA has been reported among patients with previously suppressed viral loads, affecting clinical patient care and leading to repeat measurements of viral load and drug resistance. This rise seems to have coincided with the increased use of plasma preparation tubes (PPTs) for sample collection, and we have aimed to explain why PPTs might yield elevated HIV-1 RNA levels. The impacts of different sample-processing procedures on HIV-1 RNA levels were compared retrospectively. Prospectively, the presence of different cells and cell-associated HIV-1 nucleic acids in paired plasma samples from PPTs centrifuged before (PPT1) and after (PPT2) transportation to the laboratory was compared. A retrospective analysis of 4,049 patient samples with <1,000 HIV-1 RNA copies/ml showed elevated HIV-1 RNA levels in plasma from PPT1 compared with the levels from PPT2 and standard EDTA-containing tubes. Prospective data revealed cell-associated HIV-1 nucleic acids and abundant blood cells in plasma from PPT1 but not from the corresponding PPT2. The levels of HIV-1 RNA correlated with the lymphocyte counts in plasma in PPT1. Cells could be removed by the recentrifugation of PPT1 before analysis. In conclusion, the transportation of PPTs after centrifugation may render cells in the plasma fraction containing cell-associated HIV-1 nucleic acids that contribute significantly to the HIV-1 RNA copy numbers in patients with low viral loads.

Increased detectability of plasma HIV-1 RNA after introduction of a new assay and altered specimen-processing procedures

After changes to assay and specimen-processing methods, plasma human immunodeficiency virus type 1 (HIV-1) RNA was frequently detectable in patients who previously had well-suppressed HIV-1 RNA levels. This artifact is attributable to shipping frozen plasma in primary plasma preparation tubes and is not caused by the HIV-1 RNA detection assay; it can be avoided by shipping plasma in a secondary tube.

Elevation of viral load by PCR and use of plasma preparation tubes for quantification of human immunodeficiency virus type 1

HIV-1 viral load testing from 51 patients was compared in plasma samples simultaneously processed and stored in primary Vacutainer plasma preparation tubes (PPTs) and PPT sample aliquots transferred in secondary tubes before freezing, using RT-PCR quantification with an ultrasensitive method (the Roche AMPLICOR HIV-1 MONITOR). We concluded that freezing the primary sample in the PPT collection tube can artificially elevate the HIV-1 viral load. We therefore store samples as frozen aliquots in a second tube.

Approach to the Treatment-Experienced Patient

The management of treatment-experienced patients is complex and challenging. Fortunately, new agents continue to be developed that offer hope to those who have developed resistance to currently available agents. Knowing when, how, and in whom to use new agents is never easy and highlights the importance of expert care for HIV-infected patients. The management of treatment-experienced patients requires considerable expertise, especially now that patients with highly resistant virus can hope to achieve full virologic suppression.

Evaluation and management of early virological failure

PURPOSE OF REVIEW

To describe the causes, evaluation, and management of early virological failure in patients treated with their first antiretroviral regimen.

RECENT FINDINGS

Combination antiretroviral therapy predictably induces a rapid virological response, with the majority of patients achieving an undetectable HIV-RNA load by week 24. In clinical trials and cohorts, rates of virological suppression have improved over time. Poor adherence to therapy remains the most common cause of virological failure, and genotype resistance testing is a critical step in evaluating the optimal subsequent approach. Most studies suggest that transient HIV-RNA elevations do not warrant changing treatment, and may be a consequence of laboratory variation. For those who experience virological failure, resistance to individual components of the antiretroviral regimen is dependent on the initial choice of treatment. Once virological failure is confirmed and adherence issues addressed, a prompt change in treatment is warranted to limit the selection of further drug resistance.

SUMMARY

Resistance that occurs with early virological failure follows typical patterns, with limited resistance to most antiretroviral agents in the nucleoside reverse transcriptase and protease inhibitor classes. The likelihood of achieving virological suppression with subsequent regimens should be high so long as adherence can be assured.

HIV-1 viral load blips are of limited clinical significance

Many patients on highly active antiretroviral therapy (HAART) who achieve undetectable HIV-1 RNA levels experience transient episodes of detectable viraemia or blips, suggesting there is incomplete suppression of viral replication. This raises concern that drug resistance mutations could develop and cause eventual treatment failure. However, data from recent studies indicate that most blips are actually random biological and statistical variations around a mean viral load below detectable levels (<50 copies/mL) or due to false elevations of viral load from laboratory processing artefacts. Blips are not typically associated with the development of resistance mutations and most importantly are not associated with virological or clinical failure of previously adequate HAART.