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Ludowyke N, Phumiphanjarphak W, Apiwattanakul N, Manopwisedjaroen S, Pakakasama S, Sensorn I, Pasomsub E, Chantratita W, Hongeng S, Aiewsakun P, Thitithanyanont A. Target Enrichment Metagenomics Reveals Human Pegivirus-1 in Pediatric Hematopoietic Stem Cell Transplantation Recipients. Viruses 2022; 14:796. [PMID: 35458526 PMCID: PMC9025367 DOI: 10.3390/v14040796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Revised: 04/07/2022] [Accepted: 04/08/2022] [Indexed: 11/17/2022] Open
Abstract
Human pegivirus-1 (HPgV-1) is a lymphotropic human virus, typically considered nonpathogenic, but its infection can sometimes cause persistent viremia both in immunocompetent and immunosuppressed individuals. In a viral discovery research program in hematopoietic stem cell transplant (HSCT) pediatric patients, HPgV-1 was detected in 3 out of 14 patients (21.4%) using a target enrichment next-generation sequencing method, and the presence of the viruses was confirmed by agent-specific qRT-PCR assays. For the first time in this patient cohort, complete genomes of HPgV-1 were acquired and characterized. Phylogenetic analyses indicated that two patients had HPgV-1 genotype 2 and one had HPgV-1 genotype 3. Intra-host genomic variations were described and discussed. Our results highlight the necessity to screen HSCT patients and blood and stem cell donors to reduce the potential risk of HPgV-1 transmission.
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Affiliation(s)
- Natali Ludowyke
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (N.L.); (W.P.); (S.M.)
| | - Worakorn Phumiphanjarphak
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (N.L.); (W.P.); (S.M.)
- Pornchai Matangkasombut Center for Microbial Genomics, Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Nopporn Apiwattanakul
- Department of Pediatrics, Division of Hematology and Oncology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand; (N.A.); (S.P.); (S.H.)
| | - Suwimon Manopwisedjaroen
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (N.L.); (W.P.); (S.M.)
| | - Samart Pakakasama
- Department of Pediatrics, Division of Hematology and Oncology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand; (N.A.); (S.P.); (S.H.)
| | - Insee Sensorn
- Center for Medical Genomics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand; (I.S.); (W.C.)
| | - Ekawat Pasomsub
- Virology and Molecular Microbiology Unit, Department of Pathology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand;
| | - Wasun Chantratita
- Center for Medical Genomics, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand; (I.S.); (W.C.)
| | - Suradej Hongeng
- Department of Pediatrics, Division of Hematology and Oncology, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok 10400, Thailand; (N.A.); (S.P.); (S.H.)
| | - Pakorn Aiewsakun
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (N.L.); (W.P.); (S.M.)
- Pornchai Matangkasombut Center for Microbial Genomics, Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Arunee Thitithanyanont
- Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; (N.L.); (W.P.); (S.M.)
- Pornchai Matangkasombut Center for Microbial Genomics, Department of Microbiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
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Yu Y, Wan Z, Wang JH, Yang X, Zhang C. Review of human pegivirus: Prevalence, transmission, pathogenesis, and clinical implication. Virulence 2022; 13:324-341. [PMID: 35132924 PMCID: PMC8837232 DOI: 10.1080/21505594.2022.2029328] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Human pegivirus (HPgV-1), previously known as GB virus C (GBV-C) or hepatitis G virus (HGV), is a single-stranded positive RNA virus belonging to the genus Pegivirus of the Flaviviridae family. It is transmitted by percutaneous injuries (PIs), contaminated blood and/or blood products, sexual contact, and vertical mother-to-child transmission. It is widely prevalent in general population, especially in high-risk groups. HPgV-1 viremia is typically cleared within the first 1–2 years of infection in most healthy individuals, but may persist for longer periods of time in immunocompromised individuals and/or those co-infected by other viruses. A large body of evidences indicate that HPgV-1 persistent infection has a beneficial clinical effect on many infectious diseases, such as acquired immunodeficiency syndrome (AIDS) and hepatitis C. The beneficial effects seem to be related to a significant reduction of immune activation, and/or the inhabitation of co-infected viruses (e.g. HIV-1). HPgV-1 has a broad cellular tropism for lymphoid and myeloid cells, and preferentially replicates in bone marrow and spleen without cytopathic effect, implying a therapeutic potential. The paper aims to summarize the natural history, prevalence and distribution characteristics, and pathogenesis of HPgV-1, and discuss its association with other human viral diseases, and potential use in therapy as a biovaccine or viral vector.
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Affiliation(s)
- Yaqi Yu
- College of Life Sciences, Henan Normal University, Xinxiang, China.,Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
| | - Zhenzhou Wan
- Medical Laboratory of Taizhou Fourth People's Hospital, Taizhou, China
| | - Jian-Hua Wang
- Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Xianguang Yang
- College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Chiyu Zhang
- Shanghai Public Health Clinical Center, Fudan University, Shanghai, China
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Zimmerman J, Blackard JT. Human pegivirus type 1 infection in Asia-A review of the literature. Rev Med Virol 2021; 32:e2257. [PMID: 34038600 DOI: 10.1002/rmv.2257] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 05/13/2021] [Accepted: 05/17/2021] [Indexed: 12/16/2022]
Abstract
The human pegivirus type 1 (HPgV-1)-as known as hepatitis G virus and GB virus C-is a common single-stranded RNA flavivirus. Because few studies have demonstrated an association between HPgV-1 infection and disease, screening for HPgV-1 is not performed routinely. Nonetheless, a beneficial impact of HPgV-1 infection on HIV disease progression has been reported in multiple studies. Given the burden of HIV in Asia and the complex interactions between viral co-infections and the host, we provide a comprehensive overview of the existing data from Asia on HPgV-1 infection, including the prevalence and circulating genotypes in all Asian countries with data reported. This review highlights the research conducted thus far and emphasizes the need for additional studies on HPgV-1 across the Asian continent.
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Affiliation(s)
- Joseph Zimmerman
- Division of Digestive Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Jason T Blackard
- Division of Digestive Diseases, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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Yang N, Dai R, Zhang X. Global prevalence of human pegivirus-1 in healthy volunteer blood donors: a systematic review and meta-analysis. Vox Sang 2019; 115:107-119. [PMID: 31845353 DOI: 10.1111/vox.12876] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 11/22/2019] [Accepted: 11/26/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND AND OBJECTIVES The local prevalence of HPgV-1 has been reported from different countries worldwide, but the global prevalence of HPgV-1 remains unknown. The aim of this systematic review and meta-analysis was to gather data from the literature to estimate the prevalence of HPgV-1 in healthy volunteer blood donors in the world. MATERIALS AND METHODS We searched PubMed, EMBASE, Scopus and Google Scholar databases for records up to January 2019 and included studies reporting HPgV-1 virus prevalence amongst healthy volunteer blood donors based on the detection of HPgV-1 RNA. RESULTS In all, we included 79 studies for the systematic review and 63 for the meta-analysis. Based on the random effect meta-analysis of 35 468 volunteer blood donors, we found the global prevalence of HPgV-1 to be 3·1% (95% CI, 2·4-4·1). The pooled prevalences of HPgV-1 were 1·7% (95% CI, 1·1-2·6) in North America, 9·1% (95% CI, 6·4-12·7) in South America, 2·3% (95% CI, 2%, 2·8) in Europe and 2·4% (95% CI, 1·4-4) in Asia. Subgroup analyses based on age, gender or risk factors were not possible. CONCLUSION Approximately 3 in 100 blood donations worldwide are positive for HPgV-1 increasing the risk of infection from transfusion of their components to subsequent recipients. Further research on virus pathogenicity is required before recommending routine screening of HPgV-1 for healthy volunteer blood donors.
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Affiliation(s)
- Na Yang
- Yantai Central Blood Station, Yantai, China
| | - Run Dai
- Yantai Central Blood Station, Yantai, China
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Bhanich Supapol W, Remis RS, Raboud J, Millson M, Tappero J, Kaul R, Kulkarni P, McConnell MS, Philip AM, McNicholl JM, Roongpisuthipong A, Chotpitayasunondh T, Shaffer N, Butera S. Prevalence and correlates of GB virus C infection in HIV-infected and HIV-uninfected pregnant women in Bangkok, Thailand. J Med Virol 2010; 83:33-44. [DOI: 10.1002/jmv.21946] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Bayesian coalescent analysis reveals a high rate of molecular evolution in GB virus C. J Mol Evol 2008; 66:292-7. [PMID: 18320258 DOI: 10.1007/s00239-008-9087-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 01/24/2008] [Accepted: 02/08/2008] [Indexed: 12/22/2022]
Abstract
GB virus C/hepatitis G (GBV-C) is an RNA virus of the family Flaviviridae. Despite replicating with an RNA-dependent RNA polymerase, some previous estimates of rates of evolutionary change in GBV-C suggest that it fixes mutations at the anomalously low rate of approximately 10(-7) nucleotide substitution per site, per year. However, these estimates were largely based on the assumption that GBV-C and its close relative GBV-A (New World monkey GB viruses) codiverged with their primate hosts over millions of years. Herein, we estimated the substitution rate of GBV-C using the largest set of dated GBV-C isolates compiled to date and a Bayesian coalescent approach that utilizes the year of sampling and so is independent of the assumption of codivergence. This revealed a rate of evolutionary change approximately four orders of magnitude higher than that estimated previously, in the range of 10(-2) to 10(-3) sub/site/year, and hence in line with those previously determined for RNA viruses in general and the Flaviviridae in particular. In addition, we tested the assumption of host-virus codivergence in GBV-A by performing a reconciliation analysis of host and virus phylogenies. Strikingly, we found no statistical evidence for host-virus codivergence in GBV-A, indicating that substitution rates in the GB viruses should not be estimated from host divergence times.
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Castelain S, Francois C, Bonte D, Baron A, Horle B, Morel V, Pautard B, Duverlie G. Epidemiological and quantitative study of GBV-C infection in french polytransfused children. J Med Virol 2004; 73:596-600. [PMID: 15221905 DOI: 10.1002/jmv.20131] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
From 1999 to 2002, 246 serum samples taken from polytransfused children were tested for the presence of GB virus C (GBV-C) RNA using a real-time reverse transcription-polymerase chain reaction (RT-PCR) assay. This assay was based on the TaqMan technology and allowed viral load determination in infected children with a dynamic range from 10(3) to 10(7) genome equivalent (gEq) copies/ml. The limit of detection was estimated to 619 gEq copies/ml with a > or = 95% probability of a positive result. Thirty five sera were found to be GBV-C RNA positive, corresponding to a prevalence of GBV-C of 14.2%. The mean viral load was high, i.e., 6 +/- 1.4 log (range 3.22-7.42) gEq copies/ml, but low viral loads were also detected. Sequencing of the 5'-untranslated region (UTR) identified a majority of genotype 2 strains (82%) distributed into two subtypes, 88.5% genotype 2a and 11.5% genotype 2b. In conclusion, GBV-C active infection is very frequent in exposed populations such as polytransfused children. GBV-C RNA quantitation using real-time assay may be useful for diagnosis and follow-up of the natural history of GBV-C infection.
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Affiliation(s)
- S Castelain
- Virologie, Centre Hospitalo Universitaire, Amiens, France
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Abstract
Infections with hepatitis B and C viruses (HBV, HCV) are widespread in human populations throughout the world, and are major causes of chronic liver disease and liver cancer. HBV, HCV and the related hepatitis G virus or GB virus C (referred to here as HGV/GBV-C) are capable of establishing persistent, frequently lifelong infections characterized by high levels of continuous replication. All three viruses show substantial genetic heterogeneity, which has allowed each to be classified into a number of distinct genotypes that have different geographical distributions and associations with different risk groups for infection. Information on their past transmission and epidemiology might be obtained by estimation of the time of divergence of the different genotypes of HCV, HBV and HGV/GBV-C using knowledge of their rates of sequence change. While information on the latter is limited to short observation periods and is therefore subject to considerable error and uncertainty, the relatively recent times of origin for genotype of each virus predicted by this method (HCV, 500-2000 years; HBV, 3000 years; HGV/GBV-C, 200 years) are quite incompatible with their epidemiological distributions in human populations. They also cannot easily be reconciled with the recent evidence for species-associated variants of HBV and HGV/GBV-C in a range of non-human primates. The apparent conservatism of viruses over long periods implied by their epidemiological distributions instead suggests that nucleotide sequence change may be subject to constraints peculiar to viruses with single-stranded genomes, or with overlapping reading frames that defy attempts to reconstruct evolution according to the principles of the 'molecular clock'. Large population sizes and intense selection pressures that optimize fitness may be additional factors that set virus evolution apart from that of their hosts.
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Affiliation(s)
- P Simmonds
- Laboratory for Clinical and Molecular Virology, University of Edinburgh, Summerhall, Edinburgh EH9 1QH, UK.
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Abstract
The spread and origins of hepatitis C virus (HCV) in human populations have been the subject of extensive investigations, not least because of the importance this information would provide in predicting clinical outcomes and controlling spread of HCV in the future. However, in the absence of historical and archaeological records of infection, the evolution of HCV and other human hepatitis viruses can only be inferred indirectly from their epidemiology and by genetic analysis of contemporary virus populations. Some information on the history of the latter may be obtained by dating the time of divergence of various genotypes of HCV, hepatitis B virus (HBV) and the non-pathogenic hepatitis G virus (HGV)/GB virus-C (GBV-C). However, the relatively recent times predicted for the origin of these viruses fit poorly with their epidemiological distributions and the recent evidence for species-associated variants of HBV and HGV/GBV-C in a wide range of non-human primates. The apparent conservatism of viruses over long periods implied by these latter observations may be the result of constraints on sequence change peculiar to viruses with single-stranded genomes, or with overlapping reading frames. Large population sizes and intense selection pressures that optimize fitness may be the factors that set virus evolution apart from that of their hosts.
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Affiliation(s)
- Peter Simmonds
- Laboratory for Clinical and Molecular Virology, University of Edinburgh, Summerhall, Edinburgh EH9 1QH, UK1
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Cuceanu NM, Tuplin A, Simmonds P. Evolutionarily conserved RNA secondary structures in coding and non-coding sequences at the 3' end of the hepatitis G virus/GB-virus C genome. J Gen Virol 2001; 82:713-722. [PMID: 11257175 DOI: 10.1099/0022-1317-82-4-713] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hepatitis G virus (HGV)/GB virus C (GBV-C) causes persistent, non-pathogenic infection in a large proportion of the human population. Epidemiological and genetic evidence indicates a long-term association between HGV/GBV-C and related viruses and a range of primate species, and the co-speciation of these viruses with their hosts during primate evolution. Using a combination of covariance scanning and analysis of variability at synonymous sites, we previously demonstrated that the coding regions of HGV/GBV-C may contain extensive secondary structure of undefined function (Simmonds & Smith, Journal of Virology 73, 5787-5794, 1999 ). In this study we have carried out a detailed comparison of the structure of the 3'untranslated region (3'UTR) of HGV/GBV-C with that of the upstream NS5B coding sequence. By investigation of free energies on folding, secondary structure predictive algorithms and analysis of covariance between HGV/GBV-C genotypes 1-4 and the more distantly related HGV/GBV-C chimpanzee variant, we obtained evidence for extensive RNA secondary structure formation in both regions. In particular, the NS5B region contained long stem-loop structures of up to 38 internally paired nucleotides which were evolutionarily conserved between human and chimpanzee HGV/GBV-C variants. The prediction of similar structures in the same region of hepatitis C virus may allow the functions of these structures to be determined with a more tractable experimental model.
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Affiliation(s)
- N M Cuceanu
- Laboratory for Clinical and Molecular Virology, University of Edinburgh, Summerhall, Edinburgh EH9 1QH, UK1
| | - A Tuplin
- Laboratory for Clinical and Molecular Virology, University of Edinburgh, Summerhall, Edinburgh EH9 1QH, UK1
| | - P Simmonds
- Laboratory for Clinical and Molecular Virology, University of Edinburgh, Summerhall, Edinburgh EH9 1QH, UK1
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Mison L, Hyland C, Poidinger M, Borthwick I, Faoagali J, Aeno U, Gowans E. Hepatitis G virus genotypes in Australia, Papua New Guinea and the Solomon Islands: a possible new Pacific type identified. J Gastroenterol Hepatol 2000; 15:952-6. [PMID: 11022839 DOI: 10.1046/j.1440-1746.2000.02225.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND Hepatitis G Virus (HGV)/GB Virus-C (GBV-C) is a newly discovered RNA virus. Nucleotide sequence comparison and phylogenetic studies of the 5' untranslated region (5'UTR) within the viral genome have identified at least three different types which have provisionally been classified as type 1 (West African origin), type 2 (North American origin) and type 3 (Asian origin). METHODS AND RESULTS The products of RT-PCR were sequenced by using blood donors and patients infected with HGV/GBV-C in Australia, Papua New Guinea and the Solomon Islands to investigate the genotype distribution in this area of the world. All the Australian isolates showed strong sequence homology with type 2, while the Papua New Guinea and Solomon Islands sequences were more closely related, but differ from type 3, which has previously been reported from isolates studied within Asia. CONCLUSIONS Phylogenetic analysis suggests that these latter sequences are either a new HGV/GBV-C Pacific type or a subtype of the Asian type RNA virus. Isolates homologous with type 1 were not identified in these population groups.
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Affiliation(s)
- L Mison
- Australian Red Cross Blood Service, Queensland, Brisbane.
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Handajani R, Lusida MI, Suryohudoyo P, Adi P, Setiawan PB, Nidom CA, Soemarto R, Katayama Y, Fujii M, Hotta H. Prevalence of GB virus C/Hepatitis G virus infection among various populations in Surabaya, Indonesia, and identification of novel groups of sequence variants. J Clin Microbiol 2000; 38:662-8. [PMID: 10655364 PMCID: PMC86171 DOI: 10.1128/jcm.38.2.662-668.2000] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A molecular epidemiological study was performed to investigate the prevalence of GB virus C/hepatitis G virus (GBV-C/HGV) infection among various populations in Surabaya, Indonesia. The prevalence of GBV-C/HGV RNA, determined by reverse transcription-PCR for a portion of the NS3 region of the viral genome, was 2.7% (4 of 150) among randomly collected blood donor sera, which were all negative for both hepatitis B virus surface antigen and antibodies against hepatitis C virus (HCV). On the other hand, the prevalence among anti-HCV-positive blood donors was 17.8% (13 of 73), with the ratio being significantly higher than that observed with the anti-HCV-negative blood donors (P < 0.001). A high prevalence of GBV-C/HGV infection was also observed among patients with chronic liver disease, such as chronic hepatitis (5.7%), liver cirrhosis (11. 5%), and hepatocellular carcinoma (7.0%), and patients on maintenance hemodialysis (29.0%). No correlation was observed between GBV-C/HGV viremia and serum alanine aminotransferase levels in the populations tested, suggesting the possibility that GBV-C/HGV does not cause apparent liver injury. Phylogenetic analysis of sequences of a portion of the 5' untranslated region and the E1 region of the viral genome identified, in addition to a previously reported then novel group of GBV-C/HGV variants (group 4), another novel group of variants (group 5). This result suggests that GBV-C/HGV can be classified into at least five genetic groups. GBV-C/HGV isolates of group 4 and group 5 were each shown to comprise approximately 40% of the total Indonesian isolates.
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Affiliation(s)
- R Handajani
- Departments of Biochemistry, Faculty of Medicine, Airlangga University, Surabaya, Indonesia
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Abstract
The recently discovered hepatitis G virus (HGV) or GB virus C (GBV-C) is widely distributed in human populations, and homologues such as HGV/GBV-CCPZ and GBV-A are found in a variety of different primate species. Both epidemiological and phylogenetic analyses support the hypothesis that GB viruses coevolved with their primate hosts, although their degree of sequence similarity appears incompatible with the high rate of sequence change of HGV/GBV-C over short observation periods. Comparison of complete coding sequences (8,500 bases) of different genotypes of HGV/GBV-C showed an excess of invariant synonymous sites (at 23% of all codons) compared with the frequency expected by chance (10%). To investigate the hypothesis that RNA secondary-structure formation through internal base pairing limited sequence variability at these sites, an algorithm was developed to detect covariant sites among HGV/GBV-C sequences of different genotypes. At least 35 covariant sites that were spatially associated with potential stem-loop structures were detected, whose positions correlated with positions in the genome that showed reductions in synonymous variability. Although the functional roles of the predicted secondary structures remain unclear, the restriction of sequence change imposed by secondary-structure formation provides a mechanism for differences in net rate of accumulation of nucleotide substitutions at different sites. However, the resulting disparity between short- and long-term rates of sequence change of HGV/GBV-C violates the assumptions of the "molecular clock." This places a major restriction on the use of nucleotide or amino acid sequence comparisons to calculate times of divergence of other viruses evolving under the same structural constraints as GB viruses.
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Affiliation(s)
- P Simmonds
- Department of Medical Microbiology, University of Edinburgh, Edinburgh EH8 9AG, United Kingdom.
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