[A history of virology]. / Une histoire de la virologie.

Virology was born at the end of the 19th century from the recognition of so-called filterable infectious agents that passed through filters designed to retain bacteria. The study of these agents, in particular the tobacco mosaic virus and bacteriophages, has shown the originality of their structural and physico-chemical properties while stimulating the development of molecular biology. Animal viruses, in addition to their own characterization, have served as probes to explore the molecular functioning of eukaryotic cells, including genome organization, transcriptional regulation and mechanisms of oncogenesis. In the early 1960s, a precise definition of virions and mode of virus replication as well as an internationally recognized classification based on the molecular properties of these agents were published. Understanding the pathophysiology of viral infections over the past decades has led to the identification of many new viruses and the development of standardized procedures for virological diagnosis, specific antiviral chemotherapy and effective vaccinations. Combined with the success of more basic studies, these advances have contributed to the exceptionally positive record of virology over the past hundred year.

Title: Une histoire de la virologie. Abstract: La virologie est née à la fin du XIXe siècle de la reconnaissance d'agents infectieux, dits filtrables, qui franchissaient les filtres destinés à retenir les bactéries. L'étude de ces agents, en particulier celle du virus de la mosaïque du tabac et les bactériophages, a conduit à montrer l'originalité de leurs propriétés structurales et physico-chimiques, tout en stimulant le développement de la biologie moléculaire. Les virus des animaux, en plus de leur caractérisation, ont servi de sondes pour explorer le fonctionnement moléculaire des cellules eucaryotes, notamment l'organisation du génome, la régulation transcriptionnelle et les mécanismes d'oncogenèse. Au début des années 1960, une définition précise des virions et du mode de réplication des virus, ainsi qu'une classification internationalement reconnue fondée sur les propriétés moléculaires de ces agents, ont été publiées. Au cours des dernières décennies, la compréhension de la physiopathologie des infections virales a conduit à identifier de nombreux nouveaux virus et à développer des procédures standardisées de diagnostic virologique, une chimiothérapie antivirale spécifique et des vaccinations efficaces. Associées au succès des études plus fondamentales, ces avancées ont contribué au bilan exceptionnellement positif de la virologie au cours des cent dernières années.

[COVID-19 - The vaccine miracle must include strictness and caution]. / Covid-19 - Le miracle vaccinal doit inclure rigueur et prudence.

Outside of SARS-CoV-2 vaccines, there is little positive outlook for the control of Covid-19 epidemic. Schematically, two antagonistic and extreme strategies have been proposed, zero-covid and herd immunity. Between the two, often oscillating measures, based on medical but also societal and political considerations, have been taken without any major effect on the course of the epidemic. Vaccines are a game-changer by providing a real opportunity to sustainably protect everyone against infection and eliminate the circulation of the virus. The Pfizer, Moderna and AstraZeneca vaccines, the three currently authorized in France, overall induce remarkable protection rates of 95 %, 94 % and 70 % respectively. The surprise came from that this efficacy was obtained after a rapid development, by targeting only the viral protein S as antigen, and by using the administration of expression vectors innovative in vaccinology, consisting of either messenger RNA or recombinant adenovirus. However, bringing the epidemic under control requires a well-organized mass vaccination campaign. It also requires careful monitoring of many parameters such as the occurrence of adverse events, duration of induced immunity, vaccine efficacy against emerging variants of SARS-CoV-2, interest or not of vaccinating people already infected, vaccination of immunocompromised patients. Vaccination must be accompanied by the maintenance of barrier measures and gestures and an amplification of clinical and biological investigations both to validate its effectiveness on the Covid-19 epidemic and to prepare for future developments in vaccinology.

HIV and AIDS: a philatelic medical review.

The postage stamp can serve as a means of promoting the social, educational and philanthropic aspects of the fight against diseases in general and infectious diseases (such as AIDS, associated with HIV infection) in particular. The recent but eventful history of this virus and the disease that it causes has prompted the issue of a considerable number of postage stamps worldwide - barely fewer than the number dedicated to combating tuberculosis and malaria. The present semiotic review of 356 international postage stamps on HIV/AIDS is the first to have used a multicriterion evaluation grid based on the interpretation of indices, icons, and symbols. The stereotypes and the most novel representations and the messages conveyed on the cultural and ideological levels are thus characterized with regard to the disease's historical, scientific and epidemiological contexts. This analysis concludes with a humanist plea as an illustration of Hippocratic and Galenic values: prevention, education, solidarity, empathy, healthcare, and research.

[HIV and AIDS: a philatelic medical review]. / VIH et sida : une revue philatélique médicale.

The postage stamp can serve as a means of promoting the social, educational and philanthropic aspects of the fight against disease in general and infectious diseases (such as AIDS, associated with HIV infection) in particular. The recent but eventful history of this virus and the disease that it causes has prompted the issue of a considerable number of postage stamps worldwide - barely fewer than the number dedicated to combating tuberculosis and malaria. The present semiotic review of 356 international postage stamps on HIV/AIDS is the first to have used a multicriterion evaluation grid based on the interpretation of indices, icons, and symbols. The stereotypes and the most novel representations and the messages conveyed on the cultural and ideological levels are thus characterized with regard to the disease's historical, scientific and epidemiological context. This analysis concludes with a humanist plea as an illustration of Hippocratic and Galenic values: prevention, education, solidarity, empathy, healthcare, and research.

[Covid-19, september 2020: fall storm warning]. / Covid-19, septembre 2020 : avis de tempête automnale.

The resurgence of the Covid-19 epidemic in the fall of 2020 in France and in many countries around the world raises many questions. The situation of SARS-CoV-2 infection in France after the first epidemic wave in spring 2020 approximatively indicates more than 30,000 deaths, 3 to 4 millions people infected, 50% asymptomatic infections. These data encourage us to modify the initial perception of this infection, which was imagined to be benign, with massive, homogeneous and rapid distribution ("tsunamic"), and comprising a large majority of asymptomatic forms. This invites us to reassess the hypothesis of a major role of superspreaders in the spread of the infection, which would be more limited and discontinuous ("saltatory") than expected, as for SARS-CoV-1 and MERS-CoV. The role of viral load in the transmission and clinical expression of infection also needs to be assessed. To fight against the spread of the epidemic, generalized confinement a posteriori appears to have a disproportionate cost compared to its effectiveness, whereas the application of barrier gestures (breathing mask, hand hygiene, social distancing) should be promoted without any restriction, along with the diagnosis and temporary isolation of infected persons. While the Covid-19 epidemic is a medical challenge for human societies, it is also a moral challenge that they may not ignore.

Arguments to Support a Viral Origin of Oral Squamous Cell Carcinoma in Non-Smoker and Non-Drinker Patients.

In some western countries, an increasing incidence of oral squamous cell carcinoma (OSCC) has been observed in non-smoker non-drinker patients (NSND), mostly in women with HPV-negative OSCC. In the context of the unknown etiology and mechanisms of tumorigenesis of OSCC in NSND, we discuss data supporting the hypothesis of a viral origin not related to HPV. OSCC from NSND are characterized by an antiviral DNA methylation and gene expression signature. Based on the similar increasing incidence of oral tongue SCC (OTSCC) and oropharyngeal SCC (OPSCC) in young women and men respectively, we hypothesize that changes in sexual behaviors may lead to an increasing incidence of herpesvirus in the oral cavity, especially HSV-2, similarly to what has already been described in HPV-positive OPSCC. Because viral genome integration has not been detected in OSCC from NSND, a "hit and run" viral mechanism involving epigenome deregulation could therefore play a key role at early steps of oral carcinogenesis in this population of patients. In conclusion, epidemiological, clinical and molecular data supports a "hit and run" viral origin of OSCC from NSND.

Evaluation of liver failure in a pediatric transplant recipient of a liver allograft with inherited chromosomally integrated HHV-6B.

BACKGROUND: Active infections of human herpesvirus 6B (HHV-6B) are frequent in immunocompromised recipients after transplantation. Nevertheless, they need to be distinguished from latent inherited chromosomally integrated genomes (iciHHV-6) present in about 1% of the population to avoid unnecessary administration of toxic antivirals. METHODS: A 5-year-old child presented with acute liver allograft rejection associated with HHV-6 DNA in plasma, which led to an unfavorable outcome. We investigated the possibility of HHV-6 infection derived from an iciHHV-6 present in the donor's liver using molecular and histopathology studies in various tissues, including quantification of HHV-6 DNA, genotyping, sequencing for antiviral resistance genes, relative quantification of viral transcripts, and detection of gB and gH viral proteins. RESULTS: The presence of iciHHV-6B was evidenced in the donor with signs of reactivation in the gallbladder and transplanted liver (detection of HHV-6B mRNA and late proteins). This localized expression could have played a role in liver rejection. Low viral loads in the recipient's plasma, with identical partial U39 sequences, were in favor of viral DNA released from the transplanted liver rather than a systemic infection. CONCLUSIONS: Determination of iciHHV-6 status before transplantation should be considered to guide clinical decisions, such as antiviral prophylaxis, viral load monitoring, and antiviral therapy.

Recurrent herpetic keratitis despite antiviral prophylaxis: A virological and pharmacological study.

Recurrent herpes simplex keratitis (HSK) is a leading infectious cause of blindness in industrialized countries. Antiviral prophylaxis (AVP) may fail to prevent recurrence of HSK due to viral resistance, inadequate dosing, or poor patient compliance. In this prospective multicenter study, we enrolled immunocompetent patients with recurrent HSK despite AVP. Ocular samples were tested by PCR for herpes simplex virus 1 (HSV-1). HSV-1 drug resistance was assessed with a genotypic assay based on UL23 and UL30 gene sequencing. After curative full dose valacyclovir (VACV) treatment was started, peak and trough acyclovir (ACV) plasma concentrations were measured, and patient compliance to AVP was assessed with a questionnaire. The study sample was comprised of 43 patients. Six (14%) patients were positive for HSV-1 using PCR, of whom 5 (83%) harbored genotypically ACV-resistant (ACVR) virus, due to mutations in UL23 (n = 4) or UL30 (n = 1). Disease duration was statistically significantly longer in patients with viral resistance compared to other HSK patients [35.5 ± 23.4 years (range, 6.8-68.4 years) versus 11.1 ± 12.3 years (range, 0.8-56.3 year) respectively; Mann-Whitney p = 0.01)]. While patients were treated with full dose VACV, trough ACV plasma concentrations were below the threshold for ACV sensitivity in 9.5% of cases, and compliance was poor in 5.3% of cases. To summarize, HSV-1 resistance to ACV seems to be a significant cause of failure of prophylaxis in patients with HSK and is associated with longer disease duration. Most PCR-positive samples contained genotypically ACVR virus and identification may aid in adapting treatment. Incomplete 24-h drug coverage may also explain some cases of failure of prophylaxis.

Ancient Recombination Events between Human Herpes Simplex Viruses.

Herpes simplex viruses 1 and 2 (HSV-1 and HSV-2) are seen as close relatives but also unambiguously considered as evolutionary independent units. Here, we sequenced the genomes of 18 HSV-2 isolates characterized by divergent UL30 gene sequences to further elucidate the evolutionary history of this virus. Surprisingly, genome-wide recombination analyses showed that all HSV-2 genomes sequenced to date contain HSV-1 fragments. Using phylogenomic analyses, we could also show that two main HSV-2 lineages exist. One lineage is mostly restricted to subSaharan Africa whereas the other has reached a global distribution. Interestingly, only the worldwide lineage is characterized by ancient recombination events with HSV-1. Our findings highlight the complexity of HSV-2 evolution, a virus of putative zoonotic origin which later recombined with its human-adapted relative. They also suggest that coinfections with HSV-1 and 2 may have genomic and potentially functional consequences and should therefore be monitored more closely.

Cytokine and cellular responses to human herpesvirus-6B in patients with B-acute lymphoblastic leukemia.

Primary infection with human herpesvirus-6 (HHV-6), is followed by its lifelong persistence in the host. Most T-cell responses to HHV-6 have been characterized using peripheral blood from healthy adults; however, the role of HHV-6 infection in immune modulation has not been elucidated for some diseases. Therefore, in this study the immune response to HHV-6 infection in patients with B-acute lymphoblastic leukemia (B-ALL) was analyzed. HHV-6 load was quantified in blood samples taken at the time of diagnosis of leukemia and on remission. The same concentrations of anti- and pro-inflammatory cytokines (IL-4, IL-1, IL-6, IL-8, IL-12p70, IL-17a, TNF-α and IFN-γ) were detected in plasma samples from 20 patients with and 20 without detectable HHV-6 virus loads in blood. Characterization of T-cell responses to HHV-6 showed low specific T-cells frequencies of 2.08% and 1.46% in patients with and without detectable viral loads, respectively. IFN-γ-producing T cells were detected in 0.03%-0.23% and in 0%-0.2% of CD4+T cells, respectively. Strong production of IL-6 was detected in medium supernatants of challenged T-cells whatever the HHV-6 status of the patients (973.51 ± 210.06 versus 825.70 ± 210.81 pg/mL). However, concentrations of TNF-α and IFN-γ were low. Thus, no association between plasma concentrations of cytokines and detection of HHV-6 in blood was identified, suggesting that HHV-6 is not strongly associated with development of B-ALL. The low viral loads detected may correspond with latently infected cells. Alternatively, HHV-6B specific immune responses may be below the detection threshold of the assays used.

Human Herpesviruses 6A, 6B, and 7.

Human roseoloviruses include three different species, human herpesviruses 6A, 6B, and 7 (HHV-6A, HHV-6B, HHV-7), genetically related to human cytomegalovirus. They exhibit a wide cell tropism in vivo and, like other herpesviruses, induce a lifelong latent infection in humans. In about 1% of the general population, HHV-6 DNA is covalently integrated into the subtelomeric region of cell chromosomes (ciHHV-6). Many active infections, corresponding to primary infections, reactivations, or exogenous reinfections, are asymptomatic. They also may cause serious diseases, particularly in immunocompromised individuals, including hematopoietic stem-cell transplant (HSCT) and solid-organ transplant recipients, and acquired immunodeficiency syndrome (AIDS) patients. This opportunistic pathogenic role is formally established for HHV-6 infection and less clear for HHV-7. It mainly concerns the central-nervous system, bone marrow, lungs, gastrointestinal tract, skin, and liver. As the best example, HHV-6 causes both exanthema subitum, a benign disease associated with primary infection, and severe encephalitis associated with virus reactivations in HSCT recipients. Diagnosis using serologic and direct antigen-detection methods currently exhibits limitations. The most prominent technique is the quantification of viral DNA in blood, other body fluids, and organs by means of real-time polymerase-chain reaction (PCR). The antiviral compounds ganciclovir, foscarnet, and cidofovir are effective against active infections, but there is currently no consensus regarding the indications of treatment or specifics of drug administration. Numerous questions about HHV-6A, HHV-6B, HHV-7 are still pending, concerning in particular clinical impact and therapeutic options in immunocompromised patients.

[Diagnosis and practice of virological monitoring of infections by the human herpesviruses 6A and 6B]. / La pratique du diagnotic et du suivi virologiques des infections par les herpesvirus humains 6A et 6B.

The diagnosis of the infection by the human herpesviruses 6A and 6B (HHV-6A, HHV-6B) is based on a direct and an indirect approaches. Serological methods are mainly used to ask primary infection diagnosis and carry out epidemiological studies. However, limitations are numerous with, in particular, the existence of cross-reactivity with other herpesviruses, and the inability to differentiate the two kinds of HHV-6. Initially based on virus isolation in cell culture, direct diagnosis evolved with the development of gene amplification methods that provide sensitivity and specificity, and allow viral quantitation in many biological systems and the identification of present species. Its main current indications are the identification of active infection, the identification of the integrated form of HHV-6 (iciHHV-6, inherited chromosomally integrated HHV-6) and the monitoring of the effectiveness of antiviral treatment.

Complementary assays for monitoring susceptibility of varicella-zoster virus resistance to antivirals.

The emergence of varicella-zoster virus (VZV) resistance to current antivirals as acyclovir (ACV) constitutes a hindrance to antiviral treatment effectiveness of VZV infections, especially in immunocompromised patients. The molecular mechanisms of VZV resistance reported so far rely on the presence of mutations within thymidine kinase (TK, ORF36) and DNA polymerase (ORF28) viral genes. The aim of this work was to develop reliable and complementary diagnostic methods to detect VZV antiviral resistance: (i) a genotypic assay based on TK and DNA polymerase genes sequencing, (ii) a plaque reduction assay to determine antiviral 50% effective concentrations, and (iii) a functional assay to evaluate in vitro phosphorylation activity of recombinant TKs. As a whole, this study included the analysis of 21 VZV clinical isolates and 62 biological samples from patients experiencing VZV infection. Genetic analysis revealed 3 and 9 new amino acid changes that have not been previously described within the highly conserved TK and DNA polymerase, respectively. Then, VZV isolates bearing newly identified mutations considered as natural polymorphisms were characterized as susceptible to ACV using plaque-reduction assay in MeWo cells. In parallel, the impact of TK changes on ACV phosphorylation activity was examined using a nonradioactive in vitro enzymatic assay.

High conservation of herpes simplex virus UL5/UL52 helicase-primase complex in the era of new antiviral therapies.

The emergence of herpes simplex virus (HSV) resistance to current antiviral drugs, that all target the viral DNA polymerase, constitutes a major obstacle to antiviral treatment effectiveness of HSV infections, especially in immunocompromised patients. A novel and promising class of inhibitors of the HSV UL5/UL52 helicase-primase (HP) complex has been reported to hinder viral replication with a high potency. In this study, we describe the low natural polymorphism (interstrain identity >99.1% at both nucleotide and amino acid levels) of HSV HP complex subunits pUL5 and pUL52 among 64 HSV (32 HSV-1 and 32 HSV-2) clinical isolates, and we show that the HSV resistance profile to the first-line antiviral drug acyclovir (ACV) does not impact on the natural polymorphism of HSV HP complex. Genotypic tools and polymorphism data concerning HSV HP complex provided herein will be useful to detect drug resistance mutations in a relevant time frame when HP inhibitors (HPIs), i.e., amenamevir and pritelivir, will be available in medical practice.

[Viral infections of human central nervous system]. / Infections virales du système nerveux central chez l'homme.

The viruses that can infect the central nervous system of humans are numerous and form a heterogeneous group with respect to their structural, functional and epidemiological properties. The pathophysiological mechanisms leading to associated neurological diseases, mainly meningitis and encephalitis, also are complex and often intertwined. Overall, neurological clinical symptoms correspond either to acute viral diseases associated with primary infections or to acute, subacute or chronic diseases associated with persistent viral infections. The frequent severity of the clinical situation requires in all cases the practice of virological diagnosis for which the PCR techniques applied to cerebrospinal fluid samples occupy a prominent place. The severity of clinical manifestations justifies the use of prophylactic vaccination when available and antiviral treatment as soon as the causative virus is identified or suspected.

Où en est la recherche sur les antiviraux ?

Research for novel antivirals: where are we going? Antiviral drugs have become a critical component of anti-infective treatments, as illustrated by the development of antiretrovirals and antiviral drugs directed against hepatitis B and C viruses. Several other molecules are used in clinical practice against herpesviruses, adenoviruses, poxviruses, papillomaviruses and influenza viruses. Current antivirals often target viral enzymes involved in the replication of viral genomes. They also target the early stages of binding and intracellular penetration of viral particles and the late steps leading to their assembly, maturation and release. Most nucleoside analogs such as acyclovir and nucleotide analogs such as cidofovir, require phosphorylation prior to inhibit the activity of DNA or RNA polymerases through mechanisms of competition and optionally termination. Foscarnet, a pyrophosphate analog, makes this inhibition directly without any modification. Antiretrovirals also include protease, integrase and entry inhibitors while the neuraminidase inhibitors have proven to be effective against influenza viruses. Research for novel drugs aims at increasing the number and specificity of antivirals to overcome the current limitations of antiviral chemotherapy which include the inability to eradicate latent viral infections, emergence of resistance, adverse effects related to cell toxicity and cost. It is essential that economic imperatives do not block or distort the expected progresses in this particularly innovative field of contemporary medicine.

Où en est la recherche sur les antiviraux ? Les antiviraux sont devenus une composante essentielle des traitements anti-infectieux, comme cela est illustré par le développement des antirétroviraux et des antiviraux dirigés contre les virus des hépatites B et C. Plusieurs autres molécules sont utilisées en pratique clinique contre les herpèsvirus, adénovirus, poxvirus, papillomavirus et virus grippaux. Les antiviraux actuels ciblent fréquemment des enzymes virales impliquées dans la réplication des génomes viraux. Ils ciblent aussi les étapes précoces de fixation et de pénétration intracellulaire des particules virales, ainsi que les étapes tardives conduisant à leur assemblage, leur maturation et leur libération. La plupart des analogues nucléosidiques tels que l'aciclovir, et les analogues nucléotidiques tels que le cidofovir, nécessitent une phosphorylation préalable pour inhiber, par un mécanisme de compétition et éventuellement de terminaison, l'activité d'une ADN ou d'une ARN polymérase. Le foscarnet, analogue de pyrophosphate, exerce cette inhibition directement sans modification. Les antirétroviraux incluent également des inhibiteurs de protéase, d'intégrase et d'entrée du virus, alors que les inhibiteurs de la neuraminidase ont montré leur efficacité contre les virus grippaux. La recherche sur les antiviraux vise à augmenter leur nombre et leur spécifi- cité d'action pour dépasser les limitations actuelles de la chimiothérapie antivirale que sont l'impossibilité à éradiquer les infections virales latentes, l'émergence de la résistance, les effets indésirables liés à la relative toxicité cellulaire et le coût. Il est essentiel que les impératifs économiques ne viennent pas bloquer ou biaiser les progrès attendus dans un domaine particulièrement innovant de la médecine contemporaine.