•WHO p24 Ag analytical sensitivity with the Access combo assay was 0.22 IU/mL.•The assay detected up to 11 of the 30 seroconversion panels earlier vs other assays.•Three seroconversion panels were ...detected by the assay two bleeds before other kits.•The specificity for blood donor samples was 99.97 % with the assay.•The assay had 99.76 % specificity in hospitalized patient samples.
Fourth-generation HIV immunoassays have been developed to reduce the window period of detection during seroconversion period, allowing for the detection of early and established infections. The aim of this work was to evaluate a newly developed assay, Access HIV Ag/Ab combo on the novel high throughput DxI 9000 Access Immunoassay Analyzer (Beckman Coulter, Inc.). The assay allows for simultaneous qualitative detection and differentiation of HIV-1 p24 antigen and HIV-1/2 antibodies.
Assay performance was compared to two gold standard assays, the Abbott Architect HIV Ag/Ab Combo and Roche Elecsys HIV Duo, and assessed in a multicenter study, using a wide panel of samples (n > 9000, clinical samples and viral lysates) representative of genetic diversity for both antibodies and antigens, early phases of infection, negative, and cross-reacting samples.
The clinical sensitivity was 100 % for clinical samples as well as for viral lysates. Data on viral lysates and early detection on seroconversion panels showed a better result with the Access assay. Analytical sensitivity showed a limit of p24 detection determined around 0.2 IU/mL. The overall specificity was 99.91 %, and no interference was found using the potentially cross-reactive samples.
In conclusion, the Access HIV Ag/Ab combo assay demonstrated its ability for accurate diagnosis of chronic as well as primary HIV infections on the DxI 9000 Analyzer, despite the high level of genetic diversity of these viruses.
Objectives To estimate the prevalence of transmitted drug resistance mutations and non-B subtype circulation in antiretroviral-naive chronically HIV-1-infected patients in France. Methods Resistance ...mutations were sought in samples from 530 newly diagnosed HIV-1-infected patients from October 2006 to March 2007. Protease and reverse transcriptase mutations were identified from the 2007 Stanford Resistance Surveillance list. Results Reverse transcriptase and protease resistance mutations were determined in 466 patients with duration of seropositivity <5 years. 42% of patients were infected with non-B subtype strains (CRF02 18.3%). The overall prevalence of viruses with protease or reverse transcriptase mutations was 10.6% (95% confidence interval 6.7–16.3). The prevalence of protease inhibitor, nucleoside reverse transcriptase inhibitor and non-nucleoside reverse transcriptase inhibitor resistance-associated mutations was 4.7%, 5.8% and 2.8%, respectively. Frequency of resistance was not different in patients infected with B (9.5%) and non-B (CRF02 7.8% and other 11.2%) subtypes. Baseline characteristics such as gender, age, transmission group, country of transmission, disease stage, CD4 counts and viral load were not associated with the prevalence of transmitted drug resistance. Conclusions In France in 2006/2007, the prevalence of transmitted drug-resistant variants was 10.6%. Prevalence of transmitted drug resistance was comparable in B and non-B subtypes. Prevalence of non-B subtypes is still rising.
The report highlights an epidemiological change in the circulation of respiratory viruses in pediatric populations due to strategies adopted against COVID-19 pandemic. COVID-19 has resulted in a ...significant increase in requests for multiplex respiratory research to identify the virus responsible for the symptoms. The diagnostic needs have increased, and the number of samples analyzed in 2021-2022 is equal to the samples analyzed over the four epidemic periods preceding the pandemic. The report suggests the importance of active surveillance of respiratory viruses' circulation and new recommendations for respiratory virus detection in pediatric patients.
Highlights • HIV-1 RNA was quantified over the range of 40 to 107 copies/mL. • HIV-1 Group M subtypes A-D, F-H, J, K, CRFs AB, AE, AG, and Groups N & O validated. • Tested fresh and frozen human ...plasma (ACD-A and EDTA). • Incorporates 2 Internal Quantification Standards. • Lot to lot consistency traceable to WHO International Standard
HIV-1 diversity poses major challenges to viral load assays because genetic polymorphisms can impede nucleic acid detection. In addition to the on-going viral diversification within the HIV-1 group M ...pandemic, HIV-1 genetic diversity is further increased by non-group M infections, such as HIV-1 groups O (HIV-1-O), N and P. We here conducted a systematic evaluation of commercially available PCR assays to detect HIV-1-O isolates. We collected 25 primary HIV-1-O isolates covering all genetic clusters within HIV-1-O. Subsequently, this panel of isolates was tested on eight commercially available quantitative and five qualitative HIV-1 PCR-based assays in serial dilutions. Sequence analyses were performed for severe cases of underquantification or lack of detection. We observed differences between the assays in quantification that depended on the HIV-1-O isolate’s subgroup. All three tested HIV-1-O subgroup IV isolates were underquantified by the Roche CAP/CTM >800-fold compared to the Abbott RealTime assay. In contrast, the latter assay underquantified several subgroup I isolates >200-fold. Notably, the Xpert HIV-1 Viral Load test from Cepheid failed to detect two of the HIV-1-O isolates, whereas the Roche Cobas 8800 assay readily detected all isolates. Comparative sequence analyses identified polymorphisms in the HIV-1-O long-terminal repeat and integrase genes that likely underlie inadequate nucleic acid amplification. Potential viral load underquantification should be considered in therapeutic monitoring of HIV-1-O-infected patients. Pre-clinical assessments of HIV-1 diagnostic assays could be harmonized by establishing improved and internationally standardized panels of HIV-1 isolates that cover the dynamic diversity of circulating HIV-1 strains.
HIV-1 viral load testing is now recommended by the World Health Organization for every patient receiving antiretroviral therapy (ART).
The objective of this study is to evaluate the performance of ...commercial assays for their ability to quantify HIV-1 strains currently circulating in France.
The performances of the Generic HIV-RNA assay from Biocentric were compared to those of the Roche CAP/CTM v1.5, Roche CAP/CTM v2.0 and Abbott m2000 RealTime HIV-1 assays. A total of 1885 HIV-1 plasma samples were tested, including 684 samples from patients included in the ANRS-Primo Cohort.
We found a good concordance of quantification between the Roche v2.0 and the Biocentric assays, both of which were superior to the Roche v1.5 assay. We show moderate agreement between techniques; however, CRF02_AG strains and undetermined viruses were underestimated when quantified with the Roche CAP/CTM v2.0. In contrast, a comparison of the Biocentric and Abbott assay results showed strong agreement between assays, indicating that both are well suited for quantification of CRF02_AG strains. Moreover, a 2% underestimation of the B subtypes was observed with the Biocentric assay.
These results have implications for viral load monitoring in Western Africa, where CRF02_AG strains are highly prevalent. Closer epidemiological surveillance and evaluation of commercial assays are still necessary to better evaluate the impact of the genetic evolution of circulating viruses on HIV-RNA quantification in the regions most affected by the HIV-1 epidemic.
This work provides a detailed study on the physico-chemical characterization of a mechanized silver-gold alloy@mesoporous silica shell/pseudorotaxane nano-assembly using two main complementary ...techniques: XPS and NMR (liquid- and solid-state). The pseudorotaxane nanovalve is composed of a stalk (N-(6-aminohexyl)-aminomethyltriethoxysilane)/macrocycle (cucurbit6uril (CB6)) complex anchored to the silica shell leading to a silica/nanovalve hybrid organic-inorganic interface that has been fully characterized. The stalk introduction in the silica network was clearly demonstrated by XPS measurements, with the Si 2p peak shifting to lower energy after grafting, and through the analysis of the C 1s and N 1s core peaks, which indicated the presence of CB6 on the nanoparticle surface. For the first time, the complex formation on nanoparticles was proved by high speed (1)H MAS NMR experiments. However, these solid state NMR analyses have shown that the majority of the stalk does not interact with the CB6 macrocycle when formulated in powder after removing the solvent. This can be related to the large number of possible organizations and interactions between the stalk, the CB6 and the silica surface. These results highlight the importance of using a combination of adapted and complementary highly sensitive surface and volume characterization techniques to design tailor-made hybrid hierarchical structured nano-assemblies with controlled and efficient properties for potential biological purposes.
To determine natural phenotypic susceptibility of non-group M HIV-1 to integrase strand transfer inhibitors (INSTIs) in a large panel of 39 clinical strains from groups O, N and P and to identify ...genotypic polymorphisms according to susceptibility levels.
Susceptibility to raltegravir, elvitegravir and dolutegravir was evaluated in 36 HIV-1/O, 2 HIV-1/N and 1 HIV-1/P strains plus an HIV-1/M reference strain. IC50 values were determined after 3 days, and fold changes (FCs) were calculated relative to the HIV-1/M strain. Genotypic polymorphism was determined by amplification of codons 19-263 of the integrase; the natural occurrence of resistance-associated mutations was analysed using the main resistance algorithms and the IAS-USA list. VESPA analysis of the strain sequences was used to determine a signature pattern associated with higher FC.
Similar IC50 results were observed for the three drugs. Based on the value for the HIV-1/M reference strain, the data showed FC values <2.5 for raltegravir and dolutegravir, whereas the distribution for elvitegravir was heterogeneous, with FC > 10 for six strains (15%). Analysis of the non-M integrase sequences showed a high level of polymorphism without a major genotypic impact; it also revealed mutations that may be associated with the highest FC values obtained for elvitegravir.
Our phenotypic data showed that non-M strains are globally susceptible to the three currently used INSTIs, but the impact of the high FC values observed for some strains with elvitegravir needs to be explored. Clinical data are now needed to confirm these phenotypic results.
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