Joint host-pathogen genomic analysis identifies hepatitis B virus mutations associated with human NTCP and HLA class I variation.

Evolutionary changes in the hepatitis B virus (HBV) genome could reflect its adaptation to host-induced selective pressure. Leveraging paired human exome and ultra-deep HBV genome-sequencing data from 567 affected individuals with chronic hepatitis B, we comprehensively searched for the signatures of this evolutionary process by conducting "genome-to-genome" association tests between all human genetic variants and viral mutations. We identified significant associations between an East Asian-specific missense variant in the gene encoding the HBV entry receptor NTCP (rs2296651, NTCP S267F) and mutations within the receptor-binding region of HBV preS1. Through in silico modeling and in vitro preS1-NTCP binding assays, we observed that the associated HBV mutations are in proximity to the NTCP variant when bound and together partially increase binding affinity to NTCP S267F. Furthermore, we identified significant associations between HLA-A variation and viral mutations in HLA-A-restricted T cell epitopes. We used in silico binding prediction tools to evaluate the impact of the associated HBV mutations on HLA presentation and observed that mutations that result in weaker binding affinities to their cognate HLA alleles were enriched. Overall, our results suggest the emergence of HBV escape mutations that might alter the interaction between HBV PreS1 and its cellular receptor NTCP during viral entry into hepatocytes and confirm the role of HLA class I restriction in inducing HBV epitope variations.

A genome-wide CRISPR/Cas9 screen identifies a role for Rab5A and early endosomes in hepatitis E virus replication.

Hepatitis E virus (HEV) is a major cause of acute hepatitis worldwide. As the other positive-strand RNA viruses, it is believed to replicate its genome in a membrane-associated replication complex. However, current understanding of the host factors required for productive HEV infection is limited and the site as well as the composition of the HEV replication complex are still poorly characterized. To identify host factors required for HEV RNA replication, we performed a genome-wide CRISPR/Cas9 screen in permissive human cell lines harboring subgenomic HEV replicons allowing for positive and negative selection. Among the validated candidates, Ras-related early endosomal protein Rab5A was selected for further characterization. siRNA-mediated silencing of Rab5A and its effectors APPL1 and EEA1, but not of the late and recycling endosome components Rab7A and Rab11A, respectively, significantly reduced HEV RNA replication. Furthermore, pharmacological inhibition of Rab5A and of dynamin-2, required for the formation of early endosomes, resulted in a dose-dependent decrease of HEV RNA replication. Colocalization studies revealed close proximity of Rab5A, the HEV ORF1 protein, corresponding to the viral replicase, as well as HEV positive- and negative-strand RNA. In conclusion, we successfully exploited CRISPR/Cas9 and selectable subgenomic replicons to identify host factors of a noncytolytic virus. This approach revealed a role for Rab5A and early endosomes in HEV RNA replication, likely by serving as a scaffold for the establishment of functional replication complexes. Our findings yield insights into the HEV life cycle and the virus-host interactions required for productive infection.

Inborn errors of type I interferon immunity in patients with symptomatic acute hepatitis E.

BACKGROUND AND AIMS: The clinical spectrum of human infection by HEV ranges from asymptomatic to severe acute hepatitis. Furthermore, HEV can cause diverse neurological manifestations, especially Parsonage-Turner syndrome. Here, we used a large-scale human genomic approach to search for genetic determinants of severe clinical presentations of HEV infection. APPROACH AND RESULTS: We performed whole genome sequencing in 3 groups of study participants with PCR-proven acute HEV infection: (1) 24 patients with symptomatic acute hepatitis E; (2) 12 patients with HEV-associated Parsonage-Turner syndrome; and (3) 16 asymptomatic blood donors (controls). For variant calling and annotation, we used GATK4 best practices followed by Variant Effect Predictor (VEP) and Annovar. For variant classification, we implemented the American College of Medical Genetics and Genomics/Association for Molecular Pathology Bayesian classification framework in R. Variants with a probability of pathogenicity >0.9 were considered damaging. We used all genes with at least 1 damaging variant as input for pathway enrichment analyses.We observed a significant enrichment of type I interferon response pathways in the symptomatic hepatitis group: 10 out of 24 patients carried a damaging variant in one of 9 genes encoding either intracellular viral sensors ( IFIH1 , DDX58 , TLR3 , POLR3B , POLR3C ) or other molecules involved in type I interferon response [interferon regulatory factor 7 ( IRF7 ), MYD88 , OAS3 , GAPDH ]. We did not find any enriched pathway in the Parsonage-Turner syndrome group or in the controls. CONCLUSIONS: Our results highlight the essential role of type I interferon in preventing symptomatic acute hepatitis E.

Hepatitis E virus RNA-dependent RNA polymerase is involved in RNA replication and infectious particle production.

BACKGROUND AND AIMS: Hepatitis E virus (HEV) is one of the most common causes of acute hepatitis worldwide. Its positive-strand RNA genome encodes three open reading frames (ORF). ORF1 is translated into a large protein composed of multiple domains and is known as the viral replicase. The RNA-dependent RNA polymerase (RDRP) domain is responsible for the synthesis of viral RNA. APPROACH AND RESULTS: Here, we identified a highly conserved α-helix located in the RDRP thumb subdomain. Nuclear magnetic resonance demonstrated an amphipathic α-helix extending from amino acids 1628 to 1644 of the ORF1 protein. Functional analyses revealed a dual role of this helix in HEV RNA replication and virus production, including assembly and release. Mutations on the hydrophobic side of the amphipathic α-helix impaired RNA replication and resulted in the selection of a second-site compensatory change in the RDRP palm subdomain. Other mutations enhanced RNA replication but impaired virus assembly and/or release. CONCLUSIONS: Structure-function analyses identified a conserved amphipathic α-helix in the thumb subdomain of the HEV RDRP with a dual role in viral RNA replication and infectious particle production. This study provides structural insights into a key segment of the ORF1 protein and describes the successful use of reverse genetics in HEV, revealing functional interactions between the RDRP thumb and palm subdomains. On a broader scale, it demonstrates that the HEV replicase, similar to those of other positive-strand RNA viruses, is also involved in virus production.

[siRNA therapeutics : Current options and perspectives]. / Traitements à siRNA : état des lieux et perspectives.

Biomedical research and the pharmaceutical industry constantly explore new therapeutic strategies. A growing understanding of genetic diseases has enabled the development of «gene therapies¼. These can act either by inducing the expression of deficient genes or by silencing pathological ones. Therapies using small interfering RNA (siRNA) form a new class of treatments capable of targeting and specifically inhibiting a gene of interest. First by using lipid nanoparticles and then by engineering specific chemical modifications, progress has been made in delivering siRNA specifically into hepatocytes, representing a particular interest in the field of hepatology. The aim of this review article is to describe the mode of action of siRNA therapeutics, to review currently available treatments as well as their application, and to enumerate future treatment possibilities that are still under development.

La recherche biomédicale et l'industrie pharmaceutique s'intéressent au développement constant de nouvelles thérapies. Notre compréhension grandissante des maladies génétiques a permis le développement de nouvelles thérapies, dites « thérapies géniques ¼. Celles-ci peuvent viser à induire l'expression d'un gène lorsqu'il est déficient ou au contraire l'inhiber lorsqu'il est délétère. Les thérapies à siRNA (small interfering RNA) représentent une nouvelle classe de traitements permettant de cibler et d'inhiber spécifiquement un gène d'intérêt. Grâce à l'utilisation de nanoparticules lipidiques puis à l'aide de modifications chimiques spécifiques, des mécanismes efficaces ont été développés pour délivrer les siRNA dans les cellules du foie, représentant un intérêt particulier en hépatologie. Le but de cet article est de résumer le mode d'action des traitements à siRNA, de discuter des traitements disponibles et leur application ainsi que ceux en cours de développement.

[Metabolism and therapeutic monitoring of azathioprine in gastroenterology and hepatology]. / Métabolisme et suivi thérapeutique de l'azathioprine en gastroentérologie et hépatologie.

Azathioprine keeps an important place in the treatment of inflammatory bowel disease and autoimmune hepatitis. This molecule has a narrow therapeutic margin, associated with a risk of toxicity, particularly hematological and hepatic. Its complex metabolism is subject to genetic polymorphisms that are reflected in the inter-individual variability observed in the response to treatment and its tolerance profile. Hence, its use requires a good knowledge of this molecule. Treatment is initiated after a preliminary workup, followed by a progressive titration of the dosage while closely monitoring possible toxicities. Monitoring of blood levels of metabolites (including active ones) helps guide personalized dose adjustment.

L'azathioprine garde actuellement une place importante dans le traitement des maladies inflammatoires chroniques de l'intestin et de l'hépatite autoimmune. Il s'agit d'une molécule à marge thérapeutique étroite, associée à un risque de toxicité, notamment hématologique et hépatique. Son métabolisme complexe est influencé par des polymorphismes génétiques qui sont reflétés dans la variabilité interindividuelle observée dans la réponse au traitement et le profil de tolérance. Son utilisation nécessite donc une bonne connaissance de cette molécule. L'instauration du traitement se fait après un bilan préalable, puis une titration progressive des posologies, tout en surveillant étroitement les éventuelles toxicités. Le monitoring des concentrations sanguines des métabolites (notamment actifs) permet de guider l'adaptation personnalisée des posologies.

[Short telomere syndrome in adults: a rare entity that should be evoked]. / Syndrome des télomères courts chez l'adulte†: une entité rare qu'il faut savoir évoquer.

Short telomere syndrome (STS) is a group of rare, often underrecognized, diseases caused by defects in telomere-maintenance genes, leading to abnormal telomere shortening and associated with diverse multi-organ manifestations. In pediatric patients, STS typically presents with mucocutaneous or gastrointestinal lesions, bone marrow failure and neoplasia. In adulthood, aplastic bone marrow disease, liver disease and pulmonary fibrosis are classic clinical manifestations. At present, medical treatment options for STS remain limited. Danazol, a synthetic androgenic hormone, can slow down telomere shortening and thus limit the progression of the disease. Finally, hematopoietic, hepatic and pulmonary transplantation, sometimes combined, may be discussed in a multidisciplinary setting in certain situations.

Le syndrome des télomères courts (STC) est un groupe de maladies rares dues à un défaut dans les gènes de maintenance des télomères, provoquant leur raccourcissement anormal et des manifestations cliniques multiorganiques. Dans l'enfance, le STC se présente par des lésions mucocutanées et gastro-intestinales, une insuffisance médullaire et des néoplasies. À l'âge adulte, une atteinte médullaire aplasiante, hépatique, et une fibrose pulmonaire sont des manifestations cliniques classiques. Les options thérapeutiques pour le STC restent limitées. Le danazol, une hormone androgène synthétique, permet, parfois, de freiner le raccourcissement télomérique et de limiter la progression de la maladie. Finalement, les transplantations hématopoïétique, hépatique et pulmonaire sont discutées dans certaines situations de manière multidisciplinaire.

The histologic presentation of hepatitis E reflects patients' immune status and pre-existing liver condition.

Infection with the hepatitis E virus (HEV) is one of the main causes of acute hepatitis worldwide. Given that, the histopathology of hepatitis E is relatively poorly characterized, and it is unclear what exactly determines its remarkable variability. The aim of our study was a systematic analysis of hepatitis E histology, especially with regard to the clinical setting. Fifty-two liver samples (48 biopsies, 1 liver explant, 3 autopsy livers) from 41 patients with molecularly proven hepatitis E (28 HEV genotype (gt) 3, three gt 1, one gt 4 and 9 undetermined gt) were systematically evaluated for 33 histopathologic features. Following one approach, the biopsies were assigned to one of five generic histologic patterns. In another approach, they were subjected to hierarchical clustering. We found that 23/41 (56%) patients were immunocompromised, whereas 18 (44%) had no known immunosuppression. Five patients (12%) had pre-existing liver disease (LD). The histopathologic spectrum ranged from almost normal to acute, chronic, and steato-hepatitis to subtotal necrosis, and was thus distributed across all five generic patterns. Hierarchical clustering, however, identified three histopathologic clusters (C1-C3), which segregated along the immune status and pre-existing LD: C1 comprised mostly patients with pre-existing LD; histology mainly reflected the respective LD without pointing to the additional hepatitis E. C2 comprised mostly immunocompetent patients; histology mainly displayed florid hepatitis. C3 comprised mostly immunocompromised patients; histology mainly displayed smoldering hepatitis. Accordingly, C1-C3 differed markedly with respect to their clinical and histopathologic differential diagnoses. Hierarchical clustering suggests three groups with distinct histopathologies, indicating biologically different manifestations of hepatitis E. The association of histopathologic changes with the patient's immune status and pre-existing LD plausibly explains the diversity of hepatitis E histopathology, and suggests that these factors are the crucial underlying determinants. We expect our results to improve patient management by guiding the clinico-pathologic diagnosis of hepatitis E.

Hemostatic Alterations in Patients With Cirrhosis: From Primary Hemostasis to Fibrinolysis.

In the setting of liver cirrhosis (LC), profound hemostatic changes occur, which affect primary hemostasis, coagulation, and fibrinolysis. They involve prohemorrhagic and prothrombotic alterations at each of these steps. Patients with cirrhosis exhibit multifactorial thrombocytopenia and in vitro thrombocytopathy, counterbalanced by increased von Willebrand factor. The resultant shift is difficult to assess, but overall these changes probably result in a rebalanced primary hemostasis. Concerning coagulation, the reduced activity of coagulation factors is counterbalanced by an increase in factor VIII (produced by liver sinusoidal endothelial cells), a decrease of the natural anticoagulants, and complex changes, including changes in circulating microparticles, cell-free DNA, and neutrophil extracellular traps. Overall, these alterations result in a procoagulant state. As for fibrinolysis, increased tissue-type and urokinase-type plasminogen activators, a relatively decreased plasminogen activator inhibitor 1, and decreased levels of thrombin-activatable fibrinolysis inhibitor and α2-antiplasmin are counterbalanced by decreased plasminogen and a decreased fibrin clot permeability. Whether and how these changes shift fibrinolysis remains to be determined. Overall, the current consensus is that in patients with cirrhosis, the hemostasis is shifted toward a procoagulant state. We review the published evidence for the concept of LC as a prothrombotic state, discuss discordant data, and highlight the impact of the underlying cause of LC on the resultant imbalance.

[Advances in gastroenterology and hepatology 2020]. / Gastroentérologie et hépatologie.

The year 2020 has been dominated by the coronavirus disease 2019 (COVID-19) pandemic, with important lessons learned also in gastroenterology and hepatology. Major advances, however, have also been made in other areas, a selection of which is highlighted in this article.

L'année 2020 a été marquée par la pandémie de Covid-19. Un certain nombre d'enseignements de cette pandémie ont pu être tirés également en gastroentérologie et en hépatologie. D'autre part, des progrès importants ont aussi été réalisés en dehors du Covid-19, dont une sélection est présentée dans cet article.

[Autoimmune hepatitis: 2021 update]. / Hépatite autoimmune : mise au point 2021.

Autoimmune hepatitis is a rare disease which can present as acute or chronic forms and can be difficult to diagnose due to its variable clinical presentation. The disease arises in genetically susceptible individuals and several triggers have been identified. The diagnosis is based on the presence of autoantibodies, elevated transaminases and serum immunoglobulin G levels as well as a compatible histology. First-line immunosuppressive treatment strategies lead to clinical remission in most patients. In case of non-response, second-line therapies can be used and in case of hepatocellular insufficiency, liver transplantation remains an excellent option.

L'hépatite autoimmune est une maladie rare, pouvant se présenter sous forme aiguë ou chronique et dont le diagnostic peut être difficile à poser en raison d'une présentation clinique variable. La maladie se développe chez des personnes génétiquement prédisposées et plusieurs événements déclencheurs ont été identifiés. Le diagnostic repose sur la présence d'autoanticorps spécifiques, d'une élévation des transaminases et des immunoglobulines G, ainsi que sur une histologie compatible. Les traitements de première ligne, immunosuppresseurs, permettent dans la plupart des cas d'obtenir une rémission clinique. En cas de non-réponse, des traitements de deuxième ligne sont disponibles et lors d'insuffisance hépatocellulaire, la transplantation hépatique reste une excellente option.

Very Low Hepatitis C Viral Loads in Treatment-naive Persons: Do They Compromise Hepatitis C Virus Antigen Testing?

BACKGROUND: Hepatitis C virus (HCV) antigen testing is less expensive than quantitative reverse-transcription polymerase chain reaction but has lower sensitivity for very low viral load (VLVL; HCV RNA ≤3000 IU/mL). Currently the benefits of antigen testing for screening are discussed, but data on prevalence and outcomes of persons with VLVL are scarce. METHODS: We assessed prevalence and predictors of VLVL by logistic regression in treatment-naive participants in the Swiss Hepatitis C Cohort Study. We analyzed if the last viral load after VLVL was low, compared cirrhosis and mortality in persons with and without VLVL, and evaluated the number of samples with VLVL that were reactive by antigen testing. RESULTS: We included 2533 treatment-naive persons with available quantitative HCV RNA testing results. Overall, 133 persons (5.3%) had a VLVL. Age 18-40 years, female sex, and human immunodeficiency virus coinfection were associated with VLVL. Of 72 persons with a viral load available after VLVL, 14% had a VLVL and 17% had spontaneous viral clearance. The prevalence and incidence of cirrhosis and mortality were comparable in persons with and without VLVL; all 24 persons with VLVL and cirrhosis had excessive alcohol consumption or immunosuppression. Overall, 33% of samples with VLVL were reactive by antigen testing. CONCLUSIONS: The frequency of VLVL was low. Among the persons who would probably be missed by antigen screening, some had a favorable disease course, but some had immunosuppression and liver cirrhosis. The benefit of HCV antigen testing for screening may be limited by the risk of missing patients with severe liver disease.

Recombinant Hepatitis E Viruses Harboring Tags in the ORF1 Protein.

Hepatitis E virus (HEV) is one of the most common causes of acute hepatitis and jaundice in the world. Current understanding of the molecular virology and pathogenesis of hepatitis E is incomplete, due particularly to the limited availability of functional tools. Here, we report the development of tagged HEV genomes as a novel tool to investigate the viral life cycle. A selectable subgenomic HEV replicon was subjected to random 15-nucleotide sequence insertion using transposon-based technology. Viable insertions in the open reading frame 1 (ORF1) protein were selected in a hepatoblastoma cell line. Functional insertion sites were identified downstream of the methyltransferase domain, in the hypervariable region (HVR), and between the helicase and RNA-dependent RNA polymerase domains. HEV genomes harboring a hemagglutinin (HA) epitope tag or a small luciferase (NanoLuc) in the HVR were found to be fully functional and to allow the production of infectious virus. NanoLuc allowed quantitative monitoring of HEV infection and replication by luciferase assay. The use of HA-tagged replicons and full-length genomes allowed localization of putative sites of HEV RNA replication by the simultaneous detection of viral RNA by fluorescence in situ hybridization and of ORF1 protein by immunofluorescence. Candidate HEV replication complexes were found in cytoplasmic dot-like structures which partially overlapped ORF2 and ORF3 proteins as well as exosomal markers. Hence, tagged HEV genomes yield new insights into the viral life cycle and should allow further investigation of the structure and composition of the viral replication complex.IMPORTANCE Hepatitis E virus (HEV) infection is an important cause of acute hepatitis and may lead to chronic infection in immunocompromised patients. Knowledge of the viral life cycle is incomplete due to the limited availability of functional tools. In particular, low levels of expression of the ORF1 protein or limited sensitivity of currently available antibodies or both limit our understanding of the viral replicase. Here, we report the successful establishment of subgenomic HEV replicons and full-length genomes harboring an epitope tag or a functional reporter in the ORF1 protein. These novel tools should allow further characterization of the HEV replication complex and to improve our understanding of the viral life cycle.

Palmitoylation mediates membrane association of hepatitis E virus ORF3 protein and is required for infectious particle secretion.

Hepatitis E virus (HEV) is a positive-strand RNA virus encoding 3 open reading frames (ORF). HEV ORF3 protein is a small, hitherto poorly characterized protein involved in viral particle secretion and possibly other functions. Here, we show that HEV ORF3 protein forms membrane-associated oligomers. Immunoblot analyses of ORF3 protein expressed in cell-free vs. cellular systems suggested a posttranslational modification. Further analyses revealed that HEV ORF3 protein is palmitoylated at cysteine residues in its N-terminal region, as corroborated by 3H-palmitate labeling, the investigation of cysteine-to-alanine substitution mutants and treatment with the palmitoylation inhibitor 2-bromopalmitate (2-BP). Abrogation of palmitoylation by site-directed mutagenesis or 2-BP treatment altered the subcellular localization of ORF3 protein, reduced the stability of the protein and strongly impaired the secretion of infectious particles. Moreover, selective membrane permeabilization coupled with immunofluorescence microscopy revealed that HEV ORF3 protein is entirely exposed to the cytosolic side of the membrane, allowing to propose a model for its membrane topology and interactions required in the viral life cycle. In conclusion, palmitoylation determines the subcellular localization, membrane topology and function of HEV ORF3 protein in the HEV life cycle.

Resistance-associated substitutions in patients with chronic hepatitis C virus genotype 4 infection.

Data on the prevalence of resistance-associated substitutions (RASs) and their implications for treatment with direct-acting antivirals (DAAs) are sparse in European patients with HCV genotype 4. This study investigated RASs before and after DAA failure in different genotype 4 subtypes and evaluated retreatment efficacies. Samples of 195 genotype 4-infected patients were collected in the European Resistance Database and investigated for NS3, NS5A and NS5B RASs. Retreatment efficacies in DAA failure patients were analysed retrospectively. After NS5A inhibitor (NS5Ai) failure, subtype 4r was frequent (30%) compared to DAA-naïve patients (5%) and the number of NS5A RASs was significantly higher in subtype 4r compared to 4a or 4d (median three RASs vs no or one RAS, respectively, P < .0001). RASsL28V, L30R and M31L pre-existed in subtype 4r and were maintained after NS5Ai failure. Typical subtype 4r RASs were located in subdomain 1a of NS5A, close to membrane interaction and protein-protein interaction sites that are responsible for multimerization and hence viral replication. Retreatment of 37 DAA failure patients was highly effective with 100% SVR in prior SOF/RBV, PI/SOF and PI/NS5Ai failures. Secondary virologic failures were rare (n = 2; subtype 4d and 4r) and only observed in prior NS5Ai/SOF failures (SVR 90%). In conclusion, subtype 4r harboured considerably more RASs compared to other subtypes. A resistance-tailored retreatment using first- and second-generation DAAs was highly effective with SVR rates ≥90% across all subtypes and first-line treatment regimens.

[Early TIPS: a practical review after 15 years of scientific evidence]. / Early TIPS†: une revue pratique après 15 ans d'évidence scientifique.

Gastrointestinal bleeding related to portal hypertension of cirrhosis is associated with a significant mortality risk (10-20 %). The transjugular intrahepatic portosystemic shunt (TIPS) reduces the hepatic venous pressure gradient. Several studies have evaluated early TIPS insertion (within 72h from diagnostic endoscopy) with the aim of improving outcomes in selected patients at high risk of failure to control bleeding and/or rebleeding. The majority reported an improvement of 6-week and 1-year survival rates and a decrease in failure to control bleeding and rebleeding. Here, we review the available data and discuss the limits of early TIPS in terms of patient identification and access to the procedure.

Les patients hospitalisés pour hémorragie digestive sur hypertension portale ont un risque élevé de mortalité (10-20%). La création d'un shunt portosystémique par voie transjugulaire (TIPS) permet de diminuer le gradient de pression entre le système porte et la circulation systémique (gradient portosystémique) réduisant ainsi le risque hémorragique. Chez des patients sélectionnés à haut risque de non-contrôle et/ou de récidive hémorragique, plusieurs études ont évalué l'intérêt de l'insertion précoce d'un TIPS (early TIPS) dans les 72 heures suivant l'endoscopie diagnostique. Elles observent en majorité une amélioration de la survie à 6 semaines et 1 an et une diminution du non-contrôle ou de la récidive hémorragique. Nous proposons ici une revue des études disponibles et discutons des limites de cette stratégie en termes d'accessibilité à la technique et d'identification des patients nécessitant encore régulièrement une discussion collégiale au cas par cas.

[Hepatocellular adenoma: update 2020]. / Adénomes hépatocellulaires†: update 2020.

Hepatocellular adenomas (HA) are rare benign liver tumors known to affect mainly women of reproductive age taking oral contraception. They can be complicated by hemorrhage or malignant transformation to hepatocellular carcinoma, especially when the size of the lesion exceeds 5 cm. Magnetic resonance imaging is the most specific tool for the non-invasive characterization of HA. The discovery of mutations underlying different specific HA phenotypes has allowed the establishment of a molecular classification that modified the management of this pathology.

Les adénomes hépatocellulaires (AH) sont des tumeurs bénignes du foie rares et connues pour affecter principalement les femmes en âge de procréer prenant une contraception orale. Ils peuvent se compliquer d'hémorragie ou de transformation en carcinome hépatocellulaire, en particulier lorsque la taille de la lésion dépasse 5 cm. L'imagerie par résonance magnétique est la technique la plus spécifique pour caractériser les AH de manière non invasive. La découverte de mutations spécifiques témoignant de l'existence de différents phénotypes d'AH a permis l'établissement d'une classification moléculaire qui a modifié la prise en charge de cette pathologie.

[SARS-CoV-2 infection and solid organ transplantation]. / Infection à SARS-CoV-2 et transplantation d'organes solides.

Transplantation has become a valid therapeutic option for an increasing number of patients with end-stage organ disease. The emergence of SARS-CoV-2 coronavirus infection and associated disease (COVID-19) has alarmed the transplant community, since recommendations for adequate follow-up of organ transplant recipients during the acute phase of a pandemic are limited. Furthermore, treatment options against COVID-19 disease and adequate adjustment of immunosuppression in at risk patients remain a concern. This review summarizes current knowledge on the incidence and clinical course of SARS-CoV-2 infection in patients with solid organ transplantation. It also discusses therapeutic strategies and provides general recommendations on how to proceed with transplantation programs in a time when health care resources may become scarce.

La transplantation d'organes permet de prolonger et d'améliorer la qualité de vie d'un nombre croissant de patients. Dans le contexte de la pandémie actuelle de l'infection au coronavirus SARS-CoV-2 et de la maladie qui en découle (COVID-19), la communauté de transplantation s'interroge sur le risque encouru par les patients greffés, sur la manière d'assurer un suivi adéquat d'une population à risque, et sur le schéma thérapeutique à adopter en cas de maladie avérée. Dans cet article nous décrivons les connaissances actuelles quant à l'incidence et à l'évolution de l'infection SARS-CoV-2 chez des patients greffés. En accord avec les sociétés de discipline, nous proposons des recommandations de prise en charge thérapeutique, et amenons quelques éléments de réflexion en tenant compte d'une possible limitation des ressources et d'une situation pandémique évolutive.

Pan-Genotype Hepatitis E Virus Replication in Stem Cell-Derived Hepatocellular Systems.

BACKGROUND & AIMS: The 4 genotypes of hepatitis E virus (HEV) that infect humans (genotypes 1-4) vary in geographical distribution, transmission, and pathogenesis. Little is known about the properties of HEV or its hosts that contribute to these variations. Primary isolates grow poorly in cell culture; most studies have relied on variants adapted to cancer cell lines, which likely alter virus biology. We investigated the infection and replication of primary isolates of HEV in hepatocyte-like cells (HLCs) derived from human embryonic and induced pluripotent stem cells. METHODS: Using a cell culture-adapted genotype 3 strain and primary isolates of genotypes 1 to 4, we compared viral replication kinetics, sensitivity to drugs, and ability of HEV to activate the innate immune response. We studied HLCs using quantitative reverse-transcriptase polymerase chain reaction and immunofluorescence assay and enzyme-linked immunosorbent assays. We used an embryonic stem cell line that can be induced to express the CRISPR-Cas9 machinery to disrupt the peptidylprolyl isomerase A gene, encoding cyclophilin A (CYPA), a protein reported to inhibit replication of cell culture-adapted HEV. We further modified this line to rescue expression of CYPA before terminal differentiation to HLCs and performed HEV infection studies. RESULTS: HLCs were permissive for infection by nonadapted, primary isolates of HEV genotypes 1 to 4. HEV infection of HLCs induced a replication-dependent type III interferon response. Replication of primary HEV isolates, unlike the cell culture-adapted strain, was not affected by disruption of the peptidylprolyl isomerase A gene or exposure to the CYPA inhibitor cyclosporine A. CONCLUSIONS: Cell culture adaptations alter the replicative capacities of HEV. HLCs offer an improved, physiologically relevant, and genetically tractable system for studying the replication of primary HEV isolates. HLCs could provide a model to aid development of HEV drugs and a system to guide personalized regimens, especially for patients with chronic hepatitis E who have developed resistance to ribavirin.

Autoimmune liver serology before and after successful treatment of chronic hepatitis C by direct acting antiviral agents.

BACKGROUND AND AIMS: Chronic hepatitis C virus (HCV) infection is associated with a wide range of immunopathological manifestations, which are significantly improved by successful interferon-based treatment. There is paucity of data on the impact of interferon-free HCV clearance on immunopathological manifestations, which might be expected to disappear more frequently as compared to what reported in interferon-induced HCV-clearance. We have investigated liver autoimmune serology before and after interferon-free clearance of HCV by treatment with direct acting antiviral agents (DAA). METHOD: Patients within the Swiss Hepatitis C Cohort Study who underwent successful (SVR 12) HCV treatment with DAA were tested for autoimmune liver serology according to dedicated guidelines before and at least 6 months after end of treatment. RESULTS: A total of 235 patients were included; 62% males; median age 56 years; 27% with cirrhosis. Median time between end of DAA treatment and post-treatment serum sampling was 17 months. At least one autoantibody before treatment was found in 175 (74%) patients ; 32 (14%) were positive for 2 autoantibodies; no patient was positive for anti-SLA, anti-LC1 or typical AMA before or after DAA. ANA disappeared in 34%, SMA in 52% and anti-LKM1 in one of two patients after successful treatment, but, unexpectedly, one or more autoantibodies appeared in 27% of pre-treatment negative subjects. CONCLUSION: HCV clearance by DAA is associated with autoantibody disappearance in more than one third of the patients who were positive before treatment. However, the majority of the patients remain autoantibody-positive and 27% of those who were negative before treatment developed autoantibodies after DAA-induced HCV clearance. These data confirm that HCV infection is associated with autoimmunity and show that the autoimmune imprint persists after viral clearance by DAA, suggesting that long-term follow-up may be warranted.