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Chen M, Xu Y, Li N, Yin P, Zhou Q, Feng S, Wu T, Wei L, Wang H, Fu Y, Li YP. Development of full-length cell-culture infectious clone and subgenomic replicon for a genotype 3a isolate of hepatitis C virus. J Gen Virol 2021; 102. [DOI: 10.1099/jgv.0.001704] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hepatitis C virus (HCV) genotype 3 is widely distributed, and genotype 3-infected patients achieve a lower cure rate in direct-acting antiviral (DAA) therapy and are associated with a higher risk of hepatic steatosis than patients with other genotypes. Thus, the study of the virology and pathogenesis of genotype 3 HCV is increasingly relevant. Here, we developed a full-length infectious clone and a subgenomic replicon for the genotype 3a isolate, CH3a. From an infected serum, we constructed a full-length CH3a clone, however, it was nonviable in Huh7.5.1 cells. Next, we systematically adapted several intergenotypic recombinants containing Core-NS2 and 5′UTR-NS5A from CH3a, and other sequences from a replication-competent genotype 2 a clone JFH1. Adaptive mutations were identified, of which several combinations facilitated the replication of CH3a-JFH1 recombinants; however, they failed to adapt to the full-length CH3a and the recombinants containing CH3a NS5B. Thus, we attempted to separately adapt CH3a NS5B-3′UTR by constructing an intragenotypic recombinant using 5′UTR-NS5A from an infectious genotype 3a clone, DBN3acc, from which L3004P/M in NS5B and a deletion of 11 nucleotides (Δ11nt) downstream of the polyU/UC tract of the 3′UTR were identified and demonstrated to efficiently improve virus production. Finally, we combined functional 5′UTR-NS5A and NS5B-3′UTR sequences that carried the selected mutations to generate full-length CH3a with 26 or 27 substitutions (CH3acc), and both revealed efficient replication and virus spread in transfected and infected cells, releasing HCV of 104.2 f.f.u. ml−1. CH3acc was inhibited by DAAs targeting NS3/4A, NS5A and NS5B in a dose-dependent manner. The selected mutations permitted the development of subgenomic replicon CH3a-SGRep, by which L3004P, L3004M and Δ11nt were proven, together with a single-cycle virus production assay, to facilitate virus assembly, release, and RNA replication. CH3acc clones and CH3a-SGRep replicon provide new tools for the study of HCV genotype 3.
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Affiliation(s)
- Mingxiao Chen
- Joint Program in Pathology, Department of Internal Medicine, Guangzhou Women and Children’s Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510623, PR China
| | - Yi Xu
- Joint Program in Pathology, Department of Internal Medicine, Guangzhou Women and Children’s Medical Center, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510623, PR China
| | - Ni Li
- Institute of Human Virology, Zhongshan School of Medicine, and Key Laboratory of Tropical Disease Control of Ministry of Education, Sun Yat-sen University, Guangzhou 510080, PR China
| | - Ping Yin
- Department of Clinical Laboratory, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou 510150, PR China
| | - Qing Zhou
- Institute of Human Virology, Zhongshan School of Medicine, and Key Laboratory of Tropical Disease Control of Ministry of Education, Sun Yat-sen University, Guangzhou 510080, PR China
| | - Shengjun Feng
- Institute of Human Virology, Zhongshan School of Medicine, and Key Laboratory of Tropical Disease Control of Ministry of Education, Sun Yat-sen University, Guangzhou 510080, PR China
| | - Tiantian Wu
- Institute of Human Virology, Zhongshan School of Medicine, and Key Laboratory of Tropical Disease Control of Ministry of Education, Sun Yat-sen University, Guangzhou 510080, PR China
| | - Lai Wei
- Beijing Tsinghua Changgung Hospital, Tsinghua University, Beijing 102218, PR China
| | - Haihe Wang
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, PR China
| | - Yongshui Fu
- Guangzhou Blood Center, Guangzhou 510095, PR China
| | - Yi-Ping Li
- Institute of Human Virology, Zhongshan School of Medicine, and Key Laboratory of Tropical Disease Control of Ministry of Education, Sun Yat-sen University, Guangzhou 510080, PR China
- Department of Infectious Diseases, The Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai 519000, PR China
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Substitution of the CD81 Binding Site and β-Sandwich Area in E2 of HCV in Cambodia. Viruses 2020; 12:v12050551. [PMID: 32429467 PMCID: PMC7290788 DOI: 10.3390/v12050551] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 05/13/2020] [Accepted: 05/14/2020] [Indexed: 12/14/2022] Open
Abstract
The high genetic variability of hepatitis C virus (HCV) is the main obstacle to developing a vaccine. E2 has attracted attention for vaccine development because targeting this protein could potentially overcome issues related to the genetic diversity of HCV. In this study, we analyzed HCV genes in the general population of Cambodia and investigated the E2 locus as a candidate for vaccine development. HCV sero-epidemiological surveys were conducted between the period 2010 and 2014, with an HCV RNA–positive rate of 1.3% (11/868). Follow-up blood samples were collected from four anti-HCV– and HCV RNA– positive patients (genotype 1b: 2 cases, 6e: 1 case, 6r: 1 case) after 4.12 years. Analysis of HCV full-length nucleotide sequences in paired specimens revealed that the mutation rates of HCV genotypes 1b and 6e/6r were 1.61–2.03 × 10−3 and 2.52–2.74 × 10−3 substitutions/site/year, respectively. Non-synonymous substitutions were detected in HVR1, the front layer of the CD81 binding site, and the β-sandwich, but not in the N-terminal region or adjacent to the CD81 binding site. Therefore, we conclude that the CD81 binding site is a promising locus for HCV vaccine development.
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Xu R, Yu Y, Leitch ECM, Wang M, Huang K, Huang J, Tang X, Liao Q, Song D, Shan Z, Li C, Mclauchlan J, Rong X. HCV genotype 6 prevalence, spontaneous clearance and diversity among elderly members of the Li ethnic minority in Baisha County, China. J Viral Hepat 2019; 26:529-540. [PMID: 30629794 DOI: 10.1111/jvh.13062] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 11/16/2018] [Accepted: 11/25/2018] [Indexed: 01/01/2023]
Abstract
The epidemiology of hepatitis C virus varies widely across geographical regions and ethnic groups. Our previous study showed that 6 strains isolated from Baisha County, Hainan Island, China, were all new genotype 6 (gt6) subtypes which differed significantly from subtypes of other regions. In the current study, we conducted a comprehensive epidemiological survey of HCV in the Li ethnic group, native to Baisha County. Anti-HCV antibodies were detected by 2 independent ELISAs in all participants, and positive results confirmed by the recombinant immunoblot assay (RIBA) and HCV RNA viral loads were measured. Univariate chi-square test and multivariable logistic regression analyses were used to determine the risk factors for HCV infection and spontaneous clearance rates. Indeterminate RIBA results were excluded or included in analyses; consequently, findings were expressed as a range. Direct sequencing of partial regions within NS5B and E1 was employed for genotyping. Among 1682 participants, 117 to 153 were anti-HCV positive (7.0%-9.1%), with 42.7%-52.6% confirmed to have cleared infection. Anti-HCV positivity was associated with older age (≥60 years) (OR = 0.02, 95% CI 0.01-0.05, P < 0.01) and surgery (OR = 2.75, 95% CI 1.36-5.57, P < 0.01), with no significant difference found between the HCV infection group and the HCV spontaneous clearance group. The gt6 subtype distribution characteristics of Baisha County were unique, complex and diverse. The sequences did not cluster with known gt6 subtypes but formed 4 Baisha community-specific groups. HCV infection in members of the Li minority ethnic group is characterized by high prevalence rates in the elderly, high spontaneous clearance rates and broad gt6 diversity.
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Affiliation(s)
- Ru Xu
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, Guangdong, China
| | - Yongjuan Yu
- Department of Clinical Laboratory, People's Hospital of Baisha Li Autonomous County, Hainan, China
| | | | - Min Wang
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, Guangdong, China
| | - Ke Huang
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, Guangdong, China
| | - Jieting Huang
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, Guangdong, China
| | - Xi Tang
- School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Qiao Liao
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, Guangdong, China
| | - Dandan Song
- School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - Zhengang Shan
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, Guangdong, China
| | - Chengyao Li
- School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
| | - John Mclauchlan
- MRC-University of Glasgow Centre for Virus Research, Glasgow, UK
| | - Xia Rong
- Institute of Clinical Blood Transfusion, Guangzhou Blood Center, Guangzhou, Guangdong, China.,School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou, Guangdong, China
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Abstract
INTRODUCTION Hepatitis C virus (HCV) is divided into 7 genotypes and 67 subtypes. HCV genotype studies reflect the viral transmission patterns as well as human migration routes. In a clinical setting, HCV genotype is a baseline predictor for the sustained virological response (SVR) in chronic hepatitis C patients treated with peginterferon or some direct acting antivirals (DAAs). The Versant HCV genotype 2.0 assay has been globally used for HCV genotyping over a decade. Areas covered: The assay is based on reverse hybridization principle. It is evolved from its former versions, and the accuracy and successful genotyping/subtyping rate are substantially improved. It shows an accuracy of 99-100% for genotypes 1-6. It can also reliably identify subtypes 1a and 1b. However, the assay does not allow a high resolution for many other subtypes. Reasons for indeterminate or inaccurate genotyping/subtyping results are discussed. Expert commentary: Genotyping helps to find the most efficacious and cost-effective treatment regimen. The rapid development of anti-HCV treatment regimens, however, is greatly simplifying laboratory tests. In the near future, the need for HCV genotyping and frequent serial on-treatment HCV RNA tests will decrease along with the wide use of the more potent and pan-genotypic DAA regimens.
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Affiliation(s)
- Ruifeng Yang
- a Peking University People's Hospital, Peking University Hepatology Institute , Beijing Key Laboratory of Hepatitis C and Immunotherapy for Liver Diseases , Beijing , China
| | - Lai Wei
- a Peking University People's Hospital, Peking University Hepatology Institute , Beijing Key Laboratory of Hepatitis C and Immunotherapy for Liver Diseases , Beijing , China
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Ordeig L, Garcia-Cehic D, Gregori J, Soria ME, Nieto-Aponte L, Perales C, Llorens M, Chen Q, Riveiro-Barciela M, Buti M, Esteban R, Esteban JI, Rodriguez-Frias F, Quer J. New hepatitis C virus genotype 1 subtype naturally harbouring resistance-associated mutations to NS5A inhibitors. J Gen Virol 2018; 99:97-102. [PMID: 29239718 DOI: 10.1099/jgv.0.000996] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Hepatitis C virus (HCV) is a highly divergent virus currently classified into seven major genotypes and 86 subtypes (ICTV, June 2017), which can have differing responses to therapy. Accurate genotyping/subtyping using high-resolution HCV subtyping enables confident subtype identification, identifies mixed infections and allows detection of new subtypes. During routine genotyping/subtyping, one sample from an Equatorial Guinea patient could not be classified into any of the subtypes. The complete genomic sequence was compared to reference sequences by phylogenetic and sliding window analysis. Resistance-associated substitutions (RASs) were assessed by deep sequencing. The unclassified HCV genome did not belong to any of the existing genotype 1 (G1) subtypes. Sliding window analysis along the complete genome ruled out recombination phenomena suggesting that it belongs to a new HCV G1 subtype. Two NS5A RASs (L31V+Y93H) were found to be naturally combined in the genome which could limit treatment possibilities in patients infected with this subtype.
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Affiliation(s)
- Laura Ordeig
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
| | - Damir Garcia-Cehic
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
- Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Josep Gregori
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
- Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029, Madrid, Spain
- Roche Diagnostics SL, Sant Cugat del Vallès, 08174, Barcelona, Spain
| | - Maria Eugenia Soria
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
| | - Leonardo Nieto-Aponte
- Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029, Madrid, Spain
- Liver Pathology Unit, Department of Biochemistry and Microbiology, HUVH, 08035, Barcelona, Spain
| | - Celia Perales
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
- Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Meritxell Llorens
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
| | - Qian Chen
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
| | - Mar Riveiro-Barciela
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
- Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029, Madrid, Spain
| | - Maria Buti
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
- Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029, Madrid, Spain
- Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - Rafael Esteban
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
- Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029, Madrid, Spain
- Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - Juan Ignacio Esteban
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
- Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029, Madrid, Spain
- Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - Francisco Rodriguez-Frias
- Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029, Madrid, Spain
- Liver Pathology Unit, Department of Biochemistry and Microbiology, HUVH, 08035, Barcelona, Spain
- Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
| | - Josep Quer
- Liver Unit, Liver Disease Laboratory-Viral Hepatitis, Internal Medicine Department, Vall d'Hebron Institut Recerca (VHIR)-Hospital Universitari Vall d'Hebron (HUVH), 08035, Barcelona, Spain
- Universitat Autònoma de Barcelona, Bellaterra, 08193, Barcelona, Spain
- Centro de Investigación Biomédica en Red (CIBER) de Enfermedades Hepáticas y Digestivas (CIBERehd) del Instituto de Salud Carlos III, 28029, Madrid, Spain
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Open Label Study of 8 vs. 12 Weeks of Ledipasvir/Sofosbuvir in Genotype 6 Treatment Naïve or Experienced Patients. Am J Gastroenterol 2017; 112:1824-1831. [PMID: 29087397 DOI: 10.1038/ajg.2017.399] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/15/2017] [Indexed: 02/07/2023]
Abstract
OBJECTIVES Hepatitis C genotype 6 (HCV-GT6) is one of the most prevalent genotypes in Southeast Asia. Ledipasvir and sofosbuvir fixed-dose combination (LDV/SOF FDC) for 12 weeks has been shown to be effective for multiple HCV genotypes including treatment-naïve HCV-6. Our goal was to examine treatment outcomes in a diverse HCV-6 population. METHODS We prospectively enrolled 60 HCV-GT6 patients at four US centers. Treatment -naïve without cirrhosis patients received open-labeled LDV/SOF FDC orally once a day for 8 weeks; All cirrhotic and/or treatment-experienced patients received LDV/SOF FDC for 12 weeks. The primary outcome was sustained virological response 12 weeks after therapy (SVR12). Secondary outcomes were adverse events (AEs) and/or serious adverse events (SAEs). All patients gave written consent. RESULTS Overall mean age was 58±10 and 58% were male. All patients were Asian and foreign born. The 8-week group included 20 patients (33.3%) and the 12-week included 40 patients (66.7%). There were 2 (5%) patients with decompensation, 3 with liver cancer (7.5%), and 14 with prior treatment (35%) in the 12-week group. SVR12 was 95.0% for the 8-week group (19/20) and 95.0% for the 12-week group (38/40). AEs included fatigue (5%), insomnia (3.3%), headache (1.7%), and nausea (1.7%); however, all patients completed the intended treatment duration. There were two treatment-unrelated SAEs. CONCLUSIONS LDV/SOF FDC for 8 or 12 weeks was safe and effective for patients without cirrhosis or prior treatment failure as well as for patients with cirrhosis and/or prior treatment failure, respectively.
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HCV Genotype 6 Increased the Risk for Hepatocellular Carcinoma Among Asian Patients With Liver Cirrhosis. Am J Gastroenterol 2017; 112:1111-1119. [PMID: 28440303 DOI: 10.1038/ajg.2017.123] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 03/14/2017] [Indexed: 02/06/2023]
Abstract
OBJECTIVES Hepatitis C virus (HCV) infection is a well-documented risk factor for hepatocellular carcinoma (HCC). Seven HCV genotypes have been classified, and the genotypes show a great variety of geographic distribution. HCV genotype 6 is prevalent in Southeast Asia and has been less studied than the other genotypes. METHODS This follow-up study was designed to evaluate the natural history of HCV genotype 6. The cohort enrolled 851 Asian patients consisting of 222 with HCV genotype 6 and 629 with other genotypes. The incidence of HCC per 1,000 person-years of various HCV genotypes was estimated by dividing the new HCC cases to the person-years of follow-up. The adjusted hazards ratios (HRs) with 95% confidence intervals (CIs) were estimated by Cox's proportional hazards models. RESULTS After 4072 person-years of follow-up, there were 96 newly-developed HCC cases, confirming an incidence of 23.6 per 1000 person-years. By stratifying cirrhosis at study entry, the cumulative risk of HCC among HCV genotype 6 vs. non-6 was 2.9 vs. 2.2% for those without cirrhosis (P=0.45) and 76.2% (95% CI: 55.6-96.8%) vs. 36.2% (95% CI: 28.7-39.1%) for those with cirrhosis (P<0.05), respectively. Among patients with cirrhosis, HCV genotype 6 was significantly associated with HCC compared to patients with non-6 genotypes, with the adjusted HR=2.12 (1.33-3.39), P<0.05. In a model treating patients with genotypes other than 1 or 6 as the reference, the adjusted HR for HCC for HCV genotypes 1 and 6 were 1.13 (0.56-2.27) and 2.34 (1.12-4.86), respectively. CONCLUSIONS Among patients with cirrhosis, those with HCV genotype 6 infection should be given high priority for antiviral therapy to decrease HCC risk and for vigilant adherence to HCC surveillance.
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Bukh J. The history of hepatitis C virus (HCV): Basic research reveals unique features in phylogeny, evolution and the viral life cycle with new perspectives for epidemic control. J Hepatol 2016; 65:S2-S21. [PMID: 27641985 DOI: 10.1016/j.jhep.2016.07.035] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Accepted: 07/29/2016] [Indexed: 12/11/2022]
Abstract
The discovery of hepatitis C virus (HCV) in 1989 permitted basic research to unravel critical components of a complex life cycle for this important human pathogen. HCV is a highly divergent group of viruses classified in 7 major genotypes and a great number of subtypes, and circulating in infected individuals as a continuously evolving quasispecies destined to escape host immune responses and applied antivirals. Despite the inability to culture patient viruses directly in the laboratory, efforts to define the infectious genome of HCV resulted in development of experimental recombinant in vivo and in vitro systems, including replicons and infectious cultures in human hepatoma cell lines. And HCV has become a model virus defining new paradigms in virology, immunology and biology. For example, HCV research discovered that a virus could be completely dependent on microRNA for its replication since microRNA-122 is critical for the HCV life cycle. A number of other host molecules critical for HCV entry and replication have been identified. Thus, basic HCV research revealed important molecules for development of host targeting agents (HTA). The identification and characterization of HCV encoded proteins and their functional units contributed to the development of highly effective direct acting antivirals (DAA) against the NS3 protease, NS5A and the NS5B polymerase. In combination, these inhibitors have since 2014 permitted interferon-free therapy with cure rates above 90% among patients with chronic HCV infection; however, viral resistance represents a challenge. Worldwide control of HCV will most likely require the development of a prophylactic vaccine, and numerous candidates have been pursued. Research characterizing features critical for antibody-based virus neutralization and T cell based virus elimination from infected cells is essential for this effort. If the world community promotes an ambitious approach by applying current DAA broadly, continues to develop alternative viral- and host- targeted antivirals to combat resistant variants, and invests in the development of a vaccine, it would be possible to eradicate HCV. This would prevent about 500 thousand deaths annually. However, given the nature of HCV, the millions of new infections annually, a high chronicity rate, and with over 150 million individuals with chronic infection (which are frequently unidentified), this effort remains a major challenge for basic researchers, clinicians and communities.
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Affiliation(s)
- Jens Bukh
- Copenhagen Hepatitis C Program (CO-HEP), Department of Infectious Diseases and Clinical Research Centre, Hvidovre Hospital and Department of Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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