Immune-escape mutations and stop-codons in HBsAg develop in a large proportion of patients with chronic HBV infection exposed to anti-HBV drugs in Europe

Background: HBsAg immune-escape mutations can favor HBV-transmission also in vaccinated individuals, promote immunosuppression-driven HBV-reactivation, and increase fitness of drug-resistant strains. Stop-codons can enhance HBV oncogenic-properties. Furthermore, as a consequence of the overlapping structure of HBV genome, some immune-escape mutations or stop-codons in HBsAg can derive from drug-resistance mutations in RT. This study is aimed at gaining insight in prevalence and characteristics of immune-associated escape mutations, and stop-codons in HBsAg in chronically HBV-infected patients experiencing nucleos(t)ide analogues (NA) in Europe. Methods: This study analyzed 828 chronically HBV-infected European patients exposed to ≥ 1 NA, with detectable HBV-DNA and with an available HBsAg-sequence. The immune-associated escape mutations and the NA-induced immune-escape mutations sI195M, sI196S, and sE164D (resulting from drug-resistance mutation rtM204 V, rtM204I, and rtV173L) were retrieved from literature and examined. Mutations were defined as an aminoacid substitution with respect to a genotype A or D reference sequence. Results: At least one immune-associated escape mutation was detected in 22.1% of patients with rising temporal-trend. By multivariable-analysis, genotype-D correlated with higher selection of ≥ 1 immune-associated escape mutation (OR[95%CI]:2.20[1.32-3.67], P = 0.002). In genotype-D, the presence of ≥ 1 immune-associated escape mutations was significantly higher in drug-exposed patients with drug-resistant strains than with wild-type virus (29.5% vs 20.3% P = 0.012). Result confirmed by ana

Construction de promoteurs chimères dirigeant l'expression d'un gène rapporteur dépendante de la protéine EBNA1 de l'EBV dans les cellules épithéliales

Le virus d'Epstein-Barr (EBV) est associé à de nombreuses tumeurs épithéliales, notamment aux carcinomes du nasopharynx et carcinomes mammaires. Etant donné l'importance du nombre de patients touchés par les carcinomes mammaires et l'association de l'EBV aux tumeurs de plus mauvais pronostic, il est essentiel de proposer de nouvelles approches thérapeutiques dont la cible serait les cellules épithéliales tumorales EBV positives. L'expression de gènes viraux dans les cellules tumorales de carcinomes à l'EBV est une voie hautement sélective pour cibler l'expression de vecteurs thérapeutiques dans les cellules tumorales. La présence de la protéine virale EBNA1 dans les cellules tumorales infectées par l'EBV peut être utilisée pour activer dans ces cellules l'expression de vecteurs contenant un couple promoteur cis-activateur. La fixation de la protéine EBNA1 sir des séquences répétées de la région de la famille de répétion FR active dans les lymphocytes B de nombreux promoteurs EBV spécifiques et ubiquitaires. Nous avons étudié la combinaison du couple FR/ EBNAI avec différents promoteurs, EBV spécifiques (LMP2A actif dans les cellules épithéliales de carcinome du nasopharynx) et ubiquitaires (RSV et SV40) sur l'état d'activation et d'expression d'un gène rapporteur, le gène de la luciférase dans les cellules épithéliales. L'état d'activation et d'expression des différents promoteurs dans les cellules épithéliales mammaires infectées ou non par l'EBV a montré que l'activité des promoteurs est augmentée dans ces cellules quand FR et EBNAI1 sont présents. Cependant, cette sensibilité au couple FR/EBNA1 varie en fonction des promoteurs et du type cellulaire...PARIS7-Villemin (751102101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Failure of Fourth-Generation Enzyme Immunoassay in HIV Screening and Plasma HIV-1 RNA Detection in Recent High-Risk Behavior

Acute HIV infection was not detected in a young man presenting symptoms of sexual disease infection using fourth-generation screening tests combining HIV-specific antibody and p24 antigen. Detection of plasma HIV-1 RNA concomitant with screening tests may be proposed in individuals presenting with a symptomatic sexually transmitted infection.</jats:p

Clinical Evaluation of BioPlex 2200 HIV Ag-Ab, an Automated Screening Method Providing Discrete Detection of HIV-1 p24 Antigen, HIV-1 Antibody, and HIV-2 Antibody

ABSTRACT Early and accurate diagnosis is essential for optimal therapeutic outcomes in patients infected with HIV. Currently, none of the commercially available fourth-generation assays differentiate HIV-1 and HIV-2 antibodies (Ab) or the HIV-1 p24 antigen (Ag). The aim of this study was to evaluate the performance of a novel assay, the BioPlex 2200 HIV Ag-Ab. This assay uses a multiplex flow immunoassay design allowing the simultaneous detection and identification of antibodies to HIV-1 (groups M and O), HIV-2, and the HIV-1 p24 antigen, in addition to providing a traditional composite result. A total of 1,505 routine serum samples were prospectively tested. Results were compared with those from the Architect HIV Combo assay. The sensitivity of the BioPlex 2200 was 100%. The specificity assessed on repeated false-positive samples was 99.5%. In addition, 524 frozen specimens from patients known to be infected with HIV-1 or HIV-2 were tested. Of these specimens, 420 were infected with HIV-1, including 156 of known genotypes, 86 were infected with HIV-2, 7 were infected with HIV-1 and HIV-2, and 11 were from patients with acute HIV infection. Sensitivity was 100% for the HIV genotypes tested. The differentiation capabilities of the BioPlex 2200 HIV Ag-Ab assay for HIV-1, HIV-2, dual HIV-1/HIV-2, and early infections were 100%, 90.7%, 100%, and 90.9%, respectively. The BioPlex 2200 is a sensitive and specific assay that offers advantages over conventional HIV combo assays, also referred to as fourth-generation assays, to accurately differentiate and report HIV-1 p24 antigen and HIV-1 and HIV-2 antibodies.</jats:p