Publications by authors named "Valentin Leducq"

Antibodies to programmed cell death 1 (PD-1), Programmed death-ligand 1 (PDL-1) and Cytotoxic-T-lymphocyte-associated protein 4 (CTLA-4) can revert HIV latency and enhance anti-HIV cytotoxic response but their impact on HIV proviral sequences and integration landscape in people with HIV (PWH) remain to be studied. Two PWH treated with PD-1/PDL-1 and one with PD-1/CTLA4 were studied among the ANRS-CO-24 OncoVIHAC cohort study. Matched integration site and proviral sequencing were performed pre- and post-treatment.

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Among the various genotypes of the human papillomavirus (HPV), the HPV16 genotype is the most oncogenic by far, and some (sub)lineages may be associated with an increased risk of cancer. Thus, characterizing the full genome is important to understand the link between the HPV16 genome variability and its transforming role. We set up a multiplex PCR approach combined with Oxford Nanopore Technologies for the HPV16 full-genome characterization.

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Objectives: Mutational dynamics of SARS-CoV-2 in immunocompromised hosts, although well documented, remain a relatively unexplored mechanism. This study aims to compare the viral replication load and genetic diversity of SARS-CoV-2 in immunocompromised patients and non-immunocompromised individuals (NICs) from two major hospitals in Paris from January 2021 to May 2023.

Methods: Cycle threshold (CT) values were measured by TaqPath COVID-19 RT-PCR (Thermo Fisher Scientific).

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  • - Kaposi's sarcoma-associated herpesvirus (KSHV) is linked to various diseases, and the currently used method for detecting antibodies, the indirect immunofluorescence assay (IFA), is lengthy and dependent on the tester's skill.
  • - A study compared IFA with an enzyme-linked immunosorbent assay (ELISA) for accuracy in detecting KSHV antibodies, revealing that ELISA demonstrated better sensitivity (94%) and maintained high specificity (100%), outperforming IFA (79% sensitivity).
  • - The study suggests ELISA is a more reliable alternative for diagnosing KSHV in patients, especially those with weakened immune systems or prior inconclusive IFA results, emphasizing the need for improved serological
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  • The study investigates the reemergence of Kaposi sarcoma (KS) in people living with HIV who are on antiretroviral therapy (ART), suggesting that age-related immune decline (immunosenescence) may play a role.
  • Researchers compared data, including immune responses and viral factors, from both HIV KS patients and classic KS patients who are HIV-uninfected, while also including age-matched controls.
  • Findings indicate that despite younger ages and favorable CD4 counts in HIV KS patients, their immune profiles are similar to those of older cKS patients, pointing towards the need for new strategies to prevent and treat KS in individuals receiving ART.
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Background: High-risk patients, often immunocompromised and not responding to vaccine, continue to experience severe coronavirus disease 2019 (COVID-19) and death. Monoclonal antibodies (mAbs) were shown to be effective to prevent severe COVID-19 for these patients. Nevertheless, concerns about the emergence of resistance mutations were raised.

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  • Immunocompromised individuals tend to experience longer SARS-CoV-2 infections, increasing the chances for new mutations, especially in the spike protein, which is important for vaccines.
  • A study in Paris analyzed samples from 444 immunocompromised patients and 234 healthcare workers, finding greater genetic diversity of the virus in the immunocompromised group.
  • The research indicated that mutations in the viruses from immunocompromised patients contributed to the evolution of new variants, suggesting potential concerns for immune response and severity of future infections.
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  • A study involving 20 COVID-19 cases identified cerebral microangiopathy in six patients, marked by changes in white matter and small artery diseases as seen on MRI.
  • The condition featured perivascular alterations such as vacuolization, macrophage clusters, and large axonal swellings, suggesting blood-brain barrier disruption without evidence of direct viral presence in the brain.
  • Detection of the SARS-CoV-2 spike protein in brain endothelial cells, particularly within the Golgi apparatus, indicates a unique interaction that might affect vascular permeability and contribute to long-term neurological effects of COVID-19.
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Although France was one of the most affected European countries by the COVID-19 pandemic in 2020, the dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) movement within France, but also involving France in Europe and in the world, remain only partially characterized in this timeframe. Here, we analyzed GISAID deposited sequences from January 1 to December 31, 2020 ( = 638,706 sequences at the time of writing). To tackle the challenging number of sequences without the bias of analyzing a single subsample of sequences, we produced 100 subsamples of sequences and related phylogenetic trees from the whole dataset for different geographic scales (worldwide, European countries, and French administrative regions) and time periods (from January 1 to July 25, 2020, and from July 26 to December 31, 2020).

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  • SARS-CoV-2, the virus that causes COVID-19, has a Spike protein that binds to the ACE2 receptor and is critical for the virus's interaction with the immune system.
  • Mutations in the Spike protein lead to different variants, each with unique traits regarding how easily they spread, their severity, and their ability to evade immune responses.
  • Since early 2021, several variants have emerged, with notable lineage changes indicating a rapid evolution of SARS-CoV-2, resulting in increased transmissibility and immune evasion capabilities.
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Reprogrammed metabolism is regarded as a hallmark of cancer and offers a selective advantage to tumor cells during carcinogenesis. The redox equilibrium is necessary for growth, spread and the antioxidant pathways are boosted following Reactive Oxygen Species (ROS) production to prevent cell damage in tumor cells. Human herpesvirus 8 (HHV-8), the etiologic agent of Kaposi sarcoma KS and primary effusion lymphoma (PEL), is an oncogenic virus that disrupts cell survival-related molecular signaling pathways leading to immune host evasion, cells growths, angiogenesis and inflammatory tumor-environment.

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  • * Recovered COVID-19 patients who received one vaccine dose showed the strongest neutralizing response, while vaccinated naïve patients had high levels against earlier variants but lower activity against the Omicron variant.
  • * The surrogate assays demonstrated a good correlation with VNT results, indicating they could serve as reliable alternatives for analyzing neutralization capabilities on a larger scale, especially against resistant variants like Beta and Omicron.
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  • Monkeypox virus (MPXV) is currently spreading among men who have sex with men, particularly through close contact during sexual activities, prompting research on its distribution in the human body.
  • A study at Pitié-Salpêtrière Hospital in Paris analyzed samples from 50 men with confirmed MPXV infections across multiple anatomical sites, revealing that skin, anus, and throat had higher rates of positive samples and viral loads compared to blood, urine, and semen.
  • Over a two-week period, the proportion of positive samples from these sites significantly decreased, indicating a reduction in viral presence as the infection progressed.
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  • Large-scale screening for SARS-CoV-2 is crucial for controlling outbreaks, but new variants like Delta and Omicron may affect the reliability of rapid diagnostic tests (RDTs).
  • A study compared clinical and virological data from Delta and Omicron infections and found that the sensitivity of RDTs was significantly lower for Omicron (53.8%) compared to Delta (74.7%).
  • The research revealed that higher viral loads (VL) were present in Delta cases, which correlated with better test performance, suggesting that RDT sensitivity varies based on the variant, and repeated testing may be necessary if Omicron is suspected.
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  • The study examined healthcare-associated COVID-19 (HA-COVID-19) from September to November 2020 at Sorbonne University Hospital, revealing 209 reported cases and a significant mortality rate of 31.5% among HA-COVID-19 patients.
  • The incidence of HA-COVID-19 was closely linked to community-associated cases (CA-COVID-19) and infections among healthcare workers (HCWs), indicating considerable nosocomial transmission.
  • Whole-genome sequencing (WGS) played a crucial role in cluster investigations, helping to identify transmission routes and excluding a third of initially assigned cases, thus aiding in enhancing infection prevention and control strategies.
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Objectives: We evaluated a real-time quantitative PCR (qPCR) for detection of the (TP) genome in clinical samples through simultaneous detection of two genomic targets.

Methods: We performed qPCR with TaqMan technology using two TP genes, and , as targets, with an internal positive control. The qPCR assay was compared with syphilis diagnosis based on a combination of clinical examination, serological results and inhouse nested PCR (nPCR).

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Human Herpesvirus 8 (HHV-8) is associated with three main severe orphan malignancies, Kaposi's sarcoma (KS), multicentric Castleman's disease (MCD), and primary effusion lymphoma (PEL), which present few therapeutic options. We identified the antimalarial primaquine diphosphate (PQ) as a promising therapeutic candidate for HHV-8-associated PEL and KS. Indeed, PQ strongly reduced cell viability through caspase-dependent apoptosis, specifically in HHV-8-infected PEL cells.

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France went through three deadly epidemic waves due to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), causing major public health and socioeconomic issues. We proposed to study the course of the pandemic along 2020 from the outlook of two major Parisian hospitals earliest involved in the fight against COVID-19. Genome sequencing and phylogenetic analysis were performed on samples from patients and health care workers (HCWs) from Bichat (BCB) and Pitié-Salpêtrière (PSL) hospitals.

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Kaposi's sarcoma-associated herpesvirus (KSHV), also called human herpesvirus 8 (HHV-8), is an oncogenic virus belonging to the family. The viral particle is composed of a double-stranded DNA harboring 90 open reading frames, incorporated in an icosahedral capsid and enveloped. The viral cycle is divided in the following two states: a short lytic phase, and a latency phase that leads to a persistent infection in target cells and the expression of a small number of genes, including LANA-1, v-FLIP and v-cyclin.

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Human herpesvirus 8 (HHV8) is endemic in Africa, although studies of this infection are rare in Congo. We evaluated seroprevalence and HHV-8 diversity among people living with HIV. We included 353 patients receiving highly active antiretroviral therapy.

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Environmental factors were reported to increase the risk of human herpesvirus 8 (HHV-8) transmission. In a population of men who have sex with men (MSM), we found evidence that chemsex was associated with human herpesvirus 8 seropositivity in vivo and that poppers induced HHV-8 virion production in vitro. Our finding may explain the higher HHV-8 transmission in MSM.

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There are concerns about neutralizing antibodies' (NAbs') potency against severe acute respiratory syndrome coronavirus 2 variants. Despite decreased NAb titers elicited by BNT162b2 vaccine against VOC202012/01 and 501Y.V2 strains, 28/29 healthcare workers (HCWs) had an NAb titer ≥1:10.

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