HIV-1 low-level viraemia assessed with 3 commercial real-time PCR assays show high variability

Ruelle, Jean; Debaisieux, Laurent; Vancutsem, Ellen; Bel, Annelies De; Delforge, Marie-Luce; Piérard, Denis; Goubau, Patrick

doi:10.1186/1471-2334-12-100

Cited by 49 publications

(47 citation statements)

References 17 publications

(19 reference statements)

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“…We found that the Amplicor assay underreported pVL around its LLOQ. This is consistent both with other findings of assay variability at low pVL 14 and with the observation that switching from the Amplicor to the Taqman 1 assay (40 copy/ml LLOQ) led to increased observation of blips. 1 Of greater concern than issues of assay accuracy per se was that blip detection can imply that pVL is consistently high in the 50 to 300 copy/ml range (Fig.…”

supporting

confidence: 80%

Short Communication: HIV Blips While on Antiretroviral Therapy Can Indicate Consistently Detectable Viral Levels Due to Assay Underreporting

Murray

Zaunders²,

Koelsch³

et al. 2013

AIDS Research and Human Retroviruses

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Viral blips, where HIV RNA plasma viral load (pVL) intermittently increases above the lower limit of assay detection, are a cause for concern. We investigated a number of hypotheses for their cause. We assessed HIV RNA, and total and episomal HIV DNA from 16 individuals commencing antiretroviral therapy (ART) consisting of raltegravir and tenofovir/emtricitabine for 3 years, using two assays: a single-copy assay [SCA; lower limit of quantification (LLOQ), < 1 copy/ml] and the Amplicor assay (LLOQ of 50 copies/ml). Two individuals exhibited viral blips. From week 20 onward, the period where ART had achieved its final suppressive levels, pVL ranged from < 1 to 330 copies/ml, except for one individual at the final time. Both assays were 98% consistent (108/110) in assessing pVL < 50 copies/ml, but the Amplicor assay registered 56% of samples (19/34) as below the LLOQ that were in the 50 to 1000 copy/ml range as quantified by SCA. pVL changes between successive time points did not correlate with changes in cellular infection as measured through either total or episomal HIV DNA. Changes in pVL were correlated (negatively) with changes in total CD4+ T cell numbersPatients receiving stable, seemingly suppressive ART can have pVL near the 50 copy LLOQ at multiple time points. The high Amplicor assay error rate around this level implies that viral blips underrepresent pVL being more consistently above the LLOQ. Activation of latently infected cells is less likely to contribute to this phenomenon. S uppression of HIV plasma viral load (pVL) to as low levels as possible and for as long as possible is the primary goal of antiretroviral therapy (ART). Sudden rises of pVL in a patient after extended periods in the undetectable range ( < 50 copies/ml for many assays) can be a cause for concern for both physician and patient. A consistent increase in pVL is often a sign of ART failure, most likely due to noncompliance, low plasma drug levels, or the outgrowth of a drug-resistant viral quasispecies. The clinical implications of viral "blips," where seemingly random detectable pVL levels occur amongst undetectable ones, are less clear.A number of theories have been advanced to explain viral blips, but there are essentially two hypotheses: (1) differences in detection of pVL at or around the lower limits of assay quantification (LLOQ) occur through errors in the reproducibility of the assays and fluctuations of pVL around mean HIV RNA levels below the LLOQ 1-3 ; and (2) new rounds of viral replication arise through a variety of mechanisms resulting in rapid increases in pVL above the LLOQ from previously low levels. [4][5][6] An underlying assumption with the second hypothesis is that successful ART suppresses pVL much lower than 50 copies/ml and a blip represents a large change in pVL.We investigated these questions using data from 16 HIVinfected, therapy-naive patients [eight primary (PHI) and eight chronic (CHI)] commencing raltegravir and Truvada (tenofovir/emtricitabine) who were followed for 3 years (the PINT Study 7...

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supporting

confidence: 80%

Short Communication: HIV Blips While on Antiretroviral Therapy Can Indicate Consistently Detectable Viral Levels Due to Assay Underreporting

Murray

Zaunders²,

Koelsch³

et al. 2013

AIDS Research and Human Retroviruses

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“…Furthermore, there have been reports that real-time PCRbased assays tend to identify more patients as having low-level viremia than does the Amplicor test (10)(11)(12)(13)(14)(15). Multiple studies have documented variation between these assays when measuring samples with low viral load levels (6,13,(15)(16)(17)(18)(19)(20)(21).…”

mentioning

confidence: 99%

“…Therapy outcomes have been shown to be influenced by lowlevel viremia in some studies (16,(22)(23)(24)(25)(26)(27)(28) but not others (29)(30)(31)(32), in part reflecting differences in the measured outcomes. However, the overall clinical relevance of low-level viremia remains controversial.…”

mentioning

confidence: 99%

Comparative Performances of HIV-1 RNA Load Assays at Low Viral Load Levels: Results of an International Collaboration

et al. 2014

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Low-level viremia during antiretroviral therapy and its accurate measurement are increasingly relevant. Here, we present an international collaboration of 4,221 paired blood plasma viral load (pVL) results from four commercial assays, emphasizing the data with low pVL. The assays compared were the Abbott RealTime assay, the Roche Amplicor assay, and the Roche TaqMan version 1 and version 2 assays. The correlation between the assays was 0.90 to 0.97. However, at a low pVL, the correlation fell to 0.45 to 0.85. The observed interassay concordance was higher when detectability was defined as 200 copies/ml than when it was defined as 50 copies/ml. A pVL of ϳ100 to 125 copies/ml by the TaqMan version 1 and version 2 assays corresponded best to a 50-copies/ml threshold with the Amplicor assay. Correlation and concordance between the viral load assays were lower at a low pVL. Clear guidelines are needed on the clinical significance of low-level viremia.

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“…In addition, recent studies assessed the correlation between paired assay results at low viral loads (including the assays examined here) and found that the correlation between assays was lower at lower HIV-1 RNA results and that discordance decreased when a 200-copies/ml threshold was used versus a 50-copies/ml threshold (9, 10). These findings were not completely unexpected, based on previous studies that evaluated sources of variability in HIV-1 RNA assays (11)(12)(13), including the variability at the low end of the reportable range (14). Limit of detection for an assay refers strictly to the ability of an assay to detect the HIV-1 RNA in a sample with a Ͼ95% detection rate.…”

Section: Discussionmentioning

confidence: 99%

Comparison of Three Different FDA-Approved Plasma HIV-1 RNA Assay Platforms Confirms the Virologic Failure Endpoint of 200 Copies per Milliliter Despite Improved Assay Sensitivity

et al. 2015

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Discrepancies between HIV-1 RNA results assayed by different FDA-approved platforms have been reported. Plasma samples collected from 332 randomly selected clinical trial participants during the second year of antiretroviral treatment were assayed with three FDA-approved platforms: UltraSensitive Roche Amplicor Monitor, v1.5 (Monitor), the Abbott RealTime HIV-1 test on the m2000 system (Abbott), and the Roche TaqMan HIV-1 test, v2.0 (TaqMan). Samples from 61 additional participants with confirmed HIV-1 RNA levels of >50 copies/ml during trial follow-up were also included. Endpoints were HIV-1 RNA quantification of ≤50 copies/ml versus >50 copies/ml at an individual-sample level (primary) and determination of confirmed virologic failure (VF) from longitudinal samples. A total of 389 participants had results obtained from all assays on at least one sample (median = 6). Proportions of results of >50 copies/ml were 19% (Monitor), 22% (TaqMan), and 25% (Abbott). Despite indication of strong agreement (Cohen's kappa, 0.76 to 0.82), Abbott was more likely to detect HIV-1 RNA levels of >50 copies/ml than Monitor (matched-pair odds ratio [mOR] = 4.2; modified Obuchowski P < 0.001) and TaqMan (mOR = 2.1; P < 0.001); TaqMan was more likely than Monitor (mOR = 2.6; P < 0.001). Despite strong agreement in classifying VF across assay comparisons (kappa, 0.75 to 0.92), at a 50-copies/ml threshold, differences in the probability of VF classification (in the same direction as primary) were apparent (all McNemar's P < 0.007). At a 200-copies/ml VF threshold, no differences between assays were apparent (all P > 0.13). Despite strong agreement among assays, significant differences were observed with respect to detecting HIV-1 RNA levels of >50 copies/ml and identifying VF at the 50-copies/ml threshold. This has important implications for the definition of VF in clinical trials and clinical practice.

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HIV-1 low-level viraemia assessed with 3 commercial real-time PCR assays show high variability

Cited by 49 publications

References 17 publications

Short Communication: HIV Blips While on Antiretroviral Therapy Can Indicate Consistently Detectable Viral Levels Due to Assay Underreporting

Short Communication: HIV Blips While on Antiretroviral Therapy Can Indicate Consistently Detectable Viral Levels Due to Assay Underreporting

Comparative Performances of HIV-1 RNA Load Assays at Low Viral Load Levels: Results of an International Collaboration

Comparison of Three Different FDA-Approved Plasma HIV-1 RNA Assay Platforms Confirms the Virologic Failure Endpoint of 200 Copies per Milliliter Despite Improved Assay Sensitivity

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