Can HIV reverse transcriptase activity assay be a low-cost alternative for viral load monitoring in resource-limited settings?

Gupta, Soham; Palchaudhuri, Riya; Neogi, Ujjwal; Srinivasa, H; Ashorn, Per; Costa, Ayesha De; Källander, C. F. R.; Shet, Anita

doi:10.1136/bmjopen-2015-008795

Cited by 3 publications

(8 citation statements)

References 39 publications

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“…Patients who did not respond to ART during the 36 month follow up were classified as having TF. In accordance with the World Health Organization (WHO) guidelines, and with other studies, TF was defined as viral load > 5,000 copies/mL . In contrast, controls were identified as patients who did respond to treatment and who did not meet the criteria for TF; these patients were classified as having TS.…”

Section: Methodssupporting

confidence: 89%

Growth in children infected with HIV receiving anti‐retroviral therapy in Vietnam

Dang

Pham

Dinh

et al. 2019

Pediatrics International

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Background: There are currently two markers used to monitor treatment response to anti-retroviral therapy (ART) in HIV-infected children: CD4 T-cell count and HIV viral load; but analysis of these could be challenging in resource-poor countries. The aim of this study was therefore to determine whether change in growth parameters such as weight-for-age Z score (WAZ), height-for-age Z score (HAZ) and body mass index-for-age Z score (BMIZ) is associated with treatment response in HIV-infected children.Methods: This was a nested case-control study, in which the data were collected at enrolment and then periodically every 6 months for a total 36 month follow up of 107 HIV-infected children enrolled and treated at National Hospital of Pediatrics, Vietnam. Results: At treatment initiation, WAZ, HAZ and BMIZ were not significantly higher in the treatment success (TS) group compared with the treatment failure (TF) group. After ART initiation, WAZ and HAZ increased, and this was significant in the TS group (from À1.5 to À0.54, P < 0.01 and from À2.06 to À0.84, P < 0.01, respectively). Low HAZ was significantly associated with TF (HR, 0.71; 95% CI: 0.54-0.92). Conclusion: Height-for-age Z score was the most sensitive growth parameter in prediction of the treatment response. In order to use growth parameters, particularly HAZ as a prognosis marker for TF in clinical practice, further research should be conducted to evaluate the role of growth parameters and their effects on treatment response.

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Section: Methodssupporting

confidence: 89%

Growth in children infected with HIV receiving anti‐retroviral therapy in Vietnam

Dang

Pham

Dinh

et al. 2019

Pediatrics International

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“…However, later reports showed no association between the presence of RT inhibitors or resistance mutations with differences between RT activity and HIV-1 RNA in the plasma (23,29,32,57,58). Although our study was not designed to investigate the effect of RT inhibitors on the performance of ExaVir Load in HIV-2 infection, our results agree with these reports since no significant differences were found between viral load measurements with ExaVir Load or qPCR in treated and untreated patients.…”

Section: Discussionsupporting

confidence: 78%

“…A systematic underestimation of 0.3 log 10 copies/ml was also reported for ExaVir Load version 3 in aliquots of a World Health Organization international standard of HIV-1 subtype B (30). Greengrass et al compared ExaVir Load version 3 with Roche Cobas HIV-1 Monitor test and found a disagreement of Ͼ0.5 log 10 copies/ml in 27% of samples collected from HIV-1-infected individuals (32); this percentage was 18% when Gupta et al compared ExaVir Load version 3 to Abbot m2000rt (23).…”

Section: Discussionmentioning

confidence: 99%

“…In contrast to qPCR assays that quantify either HIV-1-or HIV-2-specific RNA, ExaVir Load measures the RT activity of HIV-1 and HIV-2. Thus, this method is, in principle, independent of the type, group, and subtype of HIV (5,20,(23)(24)(25). The ExaVir Load assay has been used extensively to monitor the viral load in HIV-1-infected patients with the same efficiency between subtypes and recombinant forms (20,23,(25)(26)(27)(28)(29) and with more consistent performance than qPCR methods in non-B subtypes (30).…”

mentioning

confidence: 99%

“…This characteristic, and its low cost, simplicity to operate, and commercial availability make it an attractive option for monitoring the HIV viral load in countries with limited resources. Indeed, ExaVir Load assay versions 1 (26,31), 2 (24,28,29,32,33), and 3 (23,29,34), with sequentially improved sensitivity and shorter turnaround times (34,35), have been used in many resource-limiting settings, in Asia and in Africa, to monitor the viral load in HIV-1-infected pediatric and adult patients undergoing antiretroviral treatment. Overall, measurements with the ExaVir Load assay showed good agreement with "goldstandard" HIV-1 viral load assays, such as Abbott M2000sp/M2000rt RealTime HIV-1 (23,30), Roche Amplicor HIV-1 Monitor (24,25,27,28,33,36), Roche Cobas Amplicor (29,30,32,34,37), Versant Bayer HIV-1 bDNA (22,33), and bioMérieux NucliSense HIV-1 QT (26).…”

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confidence: 99%

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Assessment of the Cavidi ExaVir Load Assay for Monitoring Plasma Viral Load in HIV-2-Infected Patients

et al. 2017

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HIV plasma viral load is an established marker of disease progression and of response to antiretroviral therapy, but currently there is no commercial assay validated for the quantification of viral load in HIV-2-infected individuals. We sought to make the first clinical evaluation of Cavidi ExaVir Load (version 3) in HIV-2-infected patients. Samples were collected from a total of 102 individuals living in Cape Verde, and the HIV-2 viral load was quantified by both ExaVir Load and a reference in-house real-time quantitative PCR (qPCR) used in Portugal in 91 samples. The associations between viral load and clinical prognostic variables (CD4 ϩ T cell counts and antiretroviral therapy status) were similar for measurements obtained using ExaVir Load and qPCR. There was no difference between the two methods in the capacity to discriminate between nonquantifiable and quantifiable HIV-2 in the plasma. In samples with an HIV-2 viral load quantifiable by both methods (n ϭ 27), the measurements were highly correlated (Pearson r ϭ 0.908), but the ExaVir Load values were systematically higher relative to those determined by qPCR (median difference, 0.942 log 10 copies/ml). A regression model was derived that enables the conversion of ExaVir Load results to those that would have been obtained by the reference qPCR. In conclusion, ExaVir Load version 3 is a reliable commercial assay to measure viral load in HIV-2-infected patients and therefore a valuable alternative to the inhouse assays in current use.

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Magnesium Functions as Superior Co-factor for Measuring Reverse Transcriptase Activity of HIV-1, HIV-2, and SIV

Islam

Moni

Tanaka

et al. 2020

EJMED

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This study compared different detection methods of human/simian immunodeficiency virus (HIV/SIV) infections in the cell line systems; notably, i) Indirect immunofluorescence assay (IFA), ii) integrated proviral DNA detection, iii) detection of syncytia, iv) measurement of reverse transcriptase (RT) activity. RTs of various retroviruses require cations, including Mg2+, Mn2+, Ni2+, and Cu2+, for their enzyme-activities. The study further compared the roles of Mg2+ and Mn2+ as cofactors for RT activities of freshly harvested HIV-1, HIV-2, and SIV. The NP-2/CD4/coreceptor cells were seeded for overnight and infected with viral inoculums at a multiplicity of infection (MOI) 1.0. The cells were passaged regularly in a 2-3 days interval and maintained up to 2 weeks. Infected cells were detected by indirect immunofluorescence assay (IFA). Multinucleated giant cells (MGC) in syncytia were quantified by Giemsa-staining. Proviral DNA was detected by PCR, and reverse transcriptase (RT) activity was measured. Two different cations, Mg2+ and Mn2+ were used as cofactors for RT assay. We found all the strains of HIV-1, HV-2 and SIV to infection in the cell line conveniently. IFA had identified all the viral infections in the infected cells. Proviral DNA detection, syncytia formation was observed in the infected cells. We found a better performance of Mg2+ as cofactor over Mn2+ in RT assay for HIV-1, HIV-2, SIV. Different four detection techniques of HIV/SIV infections show high level of agreement in the NP-2-based cell line system. Mg2+ remains a better cofactor for RT.

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Can HIV reverse transcriptase activity assay be a low-cost alternative for viral load monitoring in resource-limited settings?

Cited by 3 publications

References 39 publications

Growth in children infected with HIV receiving anti‐retroviral therapy in Vietnam

Growth in children infected with HIV receiving anti‐retroviral therapy in Vietnam

Assessment of the Cavidi ExaVir Load Assay for Monitoring Plasma Viral Load in HIV-2-Infected Patients

Magnesium Functions as Superior Co-factor for Measuring Reverse Transcriptase Activity of HIV-1, HIV-2, and SIV

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