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Joséphine Braun

Publications and source records attributed to Joséphine Braun.

6 recordsLinked to original sources
PubMed2005

Plasma virion reverse transcriptase activity and heat dissociation-boosted p24 assay for HIV load in Burkina Faso, West Africa.

BACKGROUND: In resource-limited settings, the requirement for inexpensive, easy-to-perform viral load monitoring has increased with greater antiretroviral drug availability. OBJECTIVES: To evaluate feasibility, in Burkina Faso, of a simple assay for plasma HIV reverse transcriptase (RT) activity quantification compared to heat dissociation-boosted (HDB) p24 antigen and RNA-based quantifications in plasma samples from HIV-infected patients. METHODS: : Plasma viraemia was quantified by RT activity, HDB-p24 and RNA copies in 84 samples from 70 HIV-1 group M-infected patients (82% non-B subtype, 93% treatment naive), including serial samples from nine patients. RESULTS: RT activity detected 86% of plasma samples containing measurable RNA copies; corresponding to 0, 93 and 100% of samples with 1.7-4.0 log(10), 4.1-4.8 log(10) and 4.9-6.7 log(10) RNA copies/ml, respectively. HDB-p24 detected 77% of plasma samples containing measurable RNA copies; corresponding to 27, 80 and 86% of samples with 1.7-4.0 log(10), 4.1-4.8 log(10) and 4.9-6.7 log(10) RNA copies/ml, respectively. Measurement error based on one-way analysis of variance between RT activity and HDB-p24 values with RNA copies showed good agreement with RT activity (ME, <10%), however poorer agreement was obtained with HDB-p24 values (ME, >10%). Patient follow up showed a similar pattern of viraemia with RNA and RT activity assays. CONCLUSION: Field trials in Burkina Faso support the practical use of plasma RT activity assay as an affordable alternative for HIV viral load determination in regions where RNA detection remains difficult to perform. HDB-p24 use requires further evaluation before being considered as an alternative method in African HIV-infected patient follow up.

Burkina Faso↗
PubMed2004

Phenotypic susceptibility to nonnucleoside inhibitors of virion-associated reverse transcriptase from different HIV types and groups.

OBJECTIVES: To evaluate a phenotype assay based on plasma reverse transcriptase (RT) to assess HIV susceptibility to nonnucleoside RT inhibitors (NNRTIs). To compare RT-based phenotype with recombinant virus assay (RVA) phenotype- and genotype-based analysis. To assess group O and HIV-2 susceptibility to NNRTIs in correlation with genotype polymorphisms. METHODS: RT activity was quantified and its susceptibility to efavirenz, nevirapine, and delavirdine measured as drug concentration resulting in 50% inhibition. RT phenotype was compared with genotype analysis. Eighteen plasma samples from 14 group M- and culture supernatants from 4 group M-, 9 group O-, and 7 HIV-2-infected patients were investigated. RT-based and RVA-based phenotypes were compared for identical plasma from 9 group M-infected patients. RESULTS: RT-based and RVA-based phenotypes were in complete agreement. RT-based phenotype- and genotype-predicted susceptibility were concordant for all but 1 group M samples. One plasma showed susceptibility to 3 NNRTIs by phenotypes, despite the presence of 101E and 106I/V residues. The HIV-2 RTs were totally resistant to the NNRTIs tested. Among HIV-1 group O, 6 were totally resistant to NNRTIs independently of the presence of the 181C mutation and 3 were susceptible to some NNRTIs. CONCLUSION: Plasma RT-based phenotype could be useful as a simple alternative for monitoring resistance to NNRTIs. This assay is suitable for highly divergent strains. It would be particularly useful for large epidemiologic survey of the natural HIV polymorphism and the potential impact in emergence of drug resistance, particularly to nevirapine, widely used to prevent mother-to-child transmission.

Anti-HIV Agents↗
PubMed2003

Plasma RNA quantification and HIV-1 divergent strains.

The diversity of HIV complicates viral load measurement for patient management and treatment monitoring. Numerous studies have shown that non-B group M variants can be underestimated and that group O strains are not detected by commercial tests. More recent versions of the kits used for previous studies have improved the quantification of non-B variants but are still unable to detect or correctly quantify group O strains. In this study, the authors evaluated the new Abbott LCx HIV RNA Quantitative viral load kit with a large collection of samples from Europe and central Africa. One hundred thirty-three group M samples, including 69 from patients infected with non-B variants, and 70 group O samples were tested. The LCx system was compared with the Cobas Amplicor HIV-1 Monitor v1.5 test and with a quantitative real-time polymerase chain reaction method based on LightCycler technology. The LCx and Cobas tests had similar quantification ranges for group M samples and a high degree of linearity (r2 = 0.9582). The LCx method quantified group O variants (31 of the 48 patients were quantifiable) and gave values within the range of those obtained with the LightCycler assay. The two assays were sensitive but showed only moderate linearity (r2 = 0.6195), probably because of higher diversity of group O strains and the use of primers and probes in different regions. In conclusion, the authors showed that the LCx kit allowed quantification of the large group M diversity and group O variants.

Cameroon↗
PubMed2003

A new quantitative HIV load assay based on plasma virion reverse transcriptase activity for the different types, groups and subtypes.

BACKGROUND: Plasma viral load monitoring is an integral part of the standard of care for HIV-infected patients in industrialized countries. In developing countries, viral load assay is either unaffordable or hindered by on-site maintenance and/or technical problems. OBJECTIVES: To evaluate a new and simple quantitative assay for plasma HIV reverse transcriptase (RT) activity; and to compare RT activity-based and RNA-based quantification in plasma samples from patients infected by different subtypes of HIV-1 group-M, HIV-1 group-O and HIV-2. METHODS: The RT-based viral load assay involves separation of the virion-protected RT and quantification of its activity with an enzyme immunoassay. Plasma viraemia was quantified both by RT activity and by RNA copies in 322 samples from 236 HIV-1 group M-infected patients, including serial samples from 54 patients. Samples from 49 patients infected by HIV-1 group O or HIV-2 were also tested. RESULTS: RT activity and RNA copies were detected in 70% of plasma samples; respectively 25% and 1% of samples contained detectable RNA copies or RT activity alone. Measured RT activity corresponded to 48%, 96% and 100% of samples with 1.7-4.0 log(10), 4.1-4.8 log(10) and 4.9-6.7 log(10) RNA copies/ml, respectively. The values of the two assays correlated independently of the HIV subtype (P < 0.0001) and group/type (P < 0.03). Patient follow-up showed a similar pattern of viraemia with the two assays. CONCLUSION: Plasma RT activity assay is a simple, cheap and reliable alternative for HIV viral load determination. As such, it could be particularly valuable for diagnosis and treatment monitoring in developing countries.

HIV Infections↗