Caractérisation des bases moléculaires de la résistance à un inhibiteur de la protéase du virus de l'immunodéficience humaine de type 1 (VIH-1) (le darunavir)

L utilisation répandue des inhibiteurs de la protéase (IPs) dans la prise en charge de l infection à VIH-1 est accompagnée par l émergence de souches virales avec une résistance croisée au sein de cette classe qui à long terme peut compromettre l efficacité des IPs. Il est donc important de connaître et de comprendre les différents mécanismes impliqués dans la résistance, notamment à l IP de dernière génération: le darunavir. Dans un premier temps, nous avons déterminé le profil de mutations associées à la réponse virologique au darunavir/ritonavir chez des patients infectés par le VIH-1 et déjà traités par des IPs. Nous avons identifié huit mutations avec un impact négatif sur la réponse virologique et deux avec un effet positif, et ainsi construit un score génotypique prédictif de la réponse virologique sur notre population. Dans un deuxième temps, nous avons déterminé les mutations de résistance sélectionnées lors d un échec au darunavir et les facteurs associés à la sélection de ces mutations. Ces facteurs sont un haut niveau de charge virale à l initiation, un petit nombre d inhibiteurs nucléosidiques de la transcriptase inverse utilisés simultanément avec le darunavir, et la présence du codon sauvage à la position L76V. Nous avons confirmé que des déterminants génétiques dans la protéase et dans gag affectent le risque de sélection de mutations de résistance au darunavir. Ainsi, la résistance au darunavir peut être expliquée par des mécanismes complexes impliquant des interactions entre les différentes mutations présentes sur l ensemble du génome. Des études complémentaires sont maintenant nécessaires pour évaluer l utilité de leur détection en pratique clinique.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

HIV Replication Is Not Controlled by CD8+ T Cells during the Acute Phase of the Infection in Humanized Mice.

HIV replication follows a well-defined pattern during the acute phase of the infection in humans. After reaching a peak during the first few weeks after infection, viral replication resolves to a set-point thereafter. There are still uncertainties regarding the contribution of CD8(+) T cells in establishing this set-point. An alternative explanation, supported by in silico modeling, would imply that viral replication is limited by the number of available targets for infection, i.e. CD4(+)CCR5(+) T cells. Here, we used NOD.SCID.gc(-/-) mice bearing human CD4(+)CCR5(+) and CD8(+) T cells derived from CD34(+) progenitors to investigate the relative contribution of both in viral control after the peak. Using low dose of a CCR5-tropic HIV virus, we observed an increase in viral replication followed by "spontaneous" resolution of the peak, similar to humans. To rule out any possible role for CD8(+) T cells in viral control, we infected mice in which CD8(+) T cells had been removed by a depleting antibody. Globally, viral replication was not affected by the absence of CD8(+) T cells. Strikingly, resolution of the viral peak was equally observed in mice with or without CD8(+) T cells, showing that CD8(+) T cells were not involved in viral control in the early phase of the infection. In contrast, a marked and specific loss of CCR5-expressing CD4(+) T cells was observed in the spleen and in the bone marrow, but not in the blood, of infected animals. Our results strongly suggest that viral replication during the acute phase of the infection in humanized mice is mainly constrained by the number of available targets in lymphoid tissues rather than by CD8(+) T cells

Impact of CD8 T cell depletion on early viral replication in HIV-infected NSG HuMice

<p>(a) Representative FACS profile of a CD8/CD4 staining in CD45⁺CD3⁺ cells from the blood 50 days after injection of PBS or 10 mg/kg of a chimeric anti-CD8 depleting antibody (+MT807R1) in 17 weeks-old NSG HuMice. (b) Viral loads (VL) were determined by Cobas Roche PCR in 17 to 36-weeks old NSG HuMice infected with 15 to 25 ng p24 of CCR5-tropic viruses 3 days after injection of PBS or the CD8-depleting antibody (CD8-depleted) (c) Area under the curve (AUC) was determined based on viremia in the blood of HuMice treated with PBS or the CD8-depleting antibody (CD8-depleted) and infected 3 days later with a CCR5-tropic HIV (Bal or NL4A8). (n.s = p>0.05 from a Mann-Whitney test).</p

Specific deletion of CD4⁺CCR5⁺ T cells in the periphery but not in the blood.

<p>Frequencies of CCR5⁺ in CD45⁺CD3⁺CD4⁺ T cells (a) and of CD4⁺ in CD45⁺CD3⁺ T cells (b) measured in the blood before and 23 days after infection of HIV-infected NSG HuMice (ns = not significant from a Wilcoxon matched-pairs signed rank test) (c) A representative FACS profile showing depletion of CCR5⁺ cells in the spleen of an infected animal is pictured. Numbers indicate the frequency of positive-cells in the depicted gate. FMO = Fluorescence minus one (d) Frequencies of CCR5⁺ cells in human CD45⁺CD3⁺ cells from the spleen and the bone marrow (BM) 37 days after HIV infection (HIV+). In this experiment, 25 weeks-old NSG HuMice were infected with 50 ng p24 of CCCR5-tropic HIV. Control mice (HIV^-) are non-infected NSG HuMice from two independent experiments euthanized at 13 and 17 weeks of age. Statistical significance was determined using the Holm-Sidak method, with alpha = 5.0%.</p

Prophylaxis by doravirine-lamivudine-tenofovir disoproxil fumarate or elvitegravir-cobicistat-emtricitabine-tenofovir alafenamide after sexual exposure to HIV

Abstract HIV post- exposure prophylaxis (PEP) is a prevention tool for individuals with a recent potential exposure to HIV. Doravirine has been available since 2019 in combination with tenofovir disoproxil fumarate and lamivudine and has not been evaluated as a PEP. DOR/3TC/TDF is our department’s most commonly prescribed PEP treatment since 2021. This study evaluates the completion rate of the DOR/3TC/TDF as compared to EVG/c/FTC/TAF for PEP, which was the regimen prescribed until 2020 in our hospital. This retrospective observational study was conducted between January 2020 and September 2021. The subjects included consecutively were adults who consulted for an HIV sexual exposure accident and for whom DOR/3TC/TDF in 2021 or EVG/c/FTC/TAF in 2020 was prescribed. The outcomes were the completion rate to the end of treatment (28 days), the seroconversion rate, and the description of side effects. During the study period, 311 people were included: 140 treated with DOR/3TC/TDF and 171 treated with EVGc/FTC/TAF. Considering subjects with a follow-up visit, the completion rate was 96.8% (90/93) in the DOR/3TC/TDF group, and 94.6% (123/130) in the EVG/c/FTC/TAF group (p-value: 0.53). The number of people lost to follow-up was nearly equivalent in both groups: 27.1% (38/140) in the DOR/3TC/TDF group and 23.4% (40/171) in the EVG/c/FTC/TAF group (p-value: 0.45). A side effect was described for 38% (36/94) in the DOR/3TC/TDF group, and 29.7% (38/128) in the EVG/c/FTC/TAF group. No cases of seroconversion were observed. DOR/3TC/TDF appears to have a similar safety profile to EVG/c/FTC/TAF. Due to its lower cost, it seems to be a treatment option for consideration in the context of HIV-exposure accidents

Evaluation of a rapid diagnostic assay for detection of SARS CoV-2 antigen in nasopharyngeal swab

International audienc

Virological efficacy of switch to DTG plus 3TC in a retrospective observational cohort of suppressed HIV-1 patients with or without past M184V: the LAMRES study

International audienceObjectives: The aim of this study was to assess the efficacy of dolutegravir plus lamivudine (DTG + 3TC) in a large set of virologically suppressed HIV-1 infected individuals with or without past M184V mutation. Methods: This observational study included individuals who switched to DTG + 3TC with ≥1 genotype before switch. Survival analysis was used to evaluate the role of past M184V on virological rebound (VR) or blips after DTG + 3TC switch. Results: A total of 712 individuals followed in several clinical centres in France, Italy and Spain were analysed. Past M184V was present in 60 (8.4%) individuals. By 3 years after switch, the overall probability of VR and blips was 6.7% and 6.9%, respectively, without any statistical significance according to the presence/absence of past M184V. A significantly higher probability of VR was found in individuals harbouring M184V before DTG + 3TC with a duration of virological suppression (Ts) ≤.3.5 years compared to others (M184V + Ts ≤.3.5 years: 22.7%; M184M + Ts ≤.3.5 years: 9.0%; M184V + Ts > 3.5 years: 7.8%; M184M + Ts > 3.5 years: 4.9%; P = 0.007). This finding was not confirmed in multivariable models adjusting for behavioural and demographic variables. Genotypic resistance test after VR under DTG + 3TC was available for 8/39 individuals; one poorly adherent individual developed M184V. No resistance to INIs was found. Conclusion: In this retrospective observational study, the probability of VR and blips in patients switching to DTG + 3TC was very low after 3 years of treatment regardless M184V. The effect of a short duration of previous virological suppression in individuals with M184V remains troubling and needs ad hoc clinical trials to be confirmed

Description of the L76V resistance protease mutation in HIV-1 B and "non-B" subtypes.

OBJECTIVE: To describe the prevalence of the L76V protease inhibitors resistance-associated mutation (PI-RAM) in relation with patients' characteristics and protease genotypic background in HIV-1 B- and "non-B"-infected patients. METHODS: Frequency of the L76V mutation between 1998 and 2010 was surveyed in the laboratory database of 3 clinical centers. Major PI-RAMs were identified according to the IAS-USA list. Fisher's and Wilcoxon tests were used to compare variables. RESULTS: Among the overall 29,643 sequences analyzed, the prevalence of L76V was 1.50%, while was 5.42% in PI-resistant viruses. Since 2008 the prevalence of L76V was higher in "non-B"-infected than in B-infected patients each year. Median time since diagnosis of HIV-1 infection and median time under antiretroviral-based regimen were both shorter in "non-B"- than in B-infected patients (8 vs 11 years, P<0.0001; and 7 vs 8 years, P = 0.004). In addition, "non-B"-infected patients had been pre-exposed to a lower number of PI (2 vs 3, P = 0.016). The L76V was also associated with a lower number of major PI-RAMs in "non-B" vs B samples (3 vs 4, P = 0.0001), and thus it was more frequent found as single major PI-RAM in "non-B" vs B subtype (10% vs 2%, P = 0.014). CONCLUSIONS: We showed an impact of viral subtype on the selection of the L76V major PI-RAM with a higher prevalence in "non-B" subtypes observed since 2008. In addition, in "non-B"-infected patients this mutation appeared more rapidly and was associated with less PI-RAM