Use of sequence analysis of the NS5B region for routine genotyping of hepatitis C virus with reference to C/E1 and 5' untranslated region sequences

Influence of hepatitis C virus and IL28B genotypes on liver stiffness

OBJECTIVE

Liver fibrosis has been associated with hepatitis C virus (HCV) genotype and genetic variation near the interleukin 28B (IL28B) gene, but the relative contribution is unknown. We aimed to investigate the relation between HCV genotypes, IL28B and development of liver stiffness.

PATIENTS AND METHODS

This cross-sectional study consists of 369 patients with chronic hepatitis C (CHC). Liver stiffness was evaluated using transient elastograhy (TE). Factors associated with development of liver fibrosis were identified by logistic regression analysis.

RESULTS

We identified 369 patients with CHC. 235 were male, 297 Caucasians, and 223 had been exposed to HCV through intravenous drug use. The overall median TE value was 7.4 kPa (interquartile range (IQR) 5.7-12.1). HCV replication was enhanced in patients carrying the IL28B CC genotype compared to TT and TC (5.8 vs. 5.4 log10 IU/mL, p = 0.03). Patients infected with HCV genotype 3 had significantly higher TE values (8.2 kPa; IQR, 5.9-14.5) compared to genotype 1 (6.9 kPa; IQR, 5.4-10.9) and 2 (6.7 kPa; IQR, 4.9-8.8) (p = 0.02). Within patients with genotype 3, IL28B CC genotype had the highest TE values (p = 0.04). However, in multivariate logistic regression, using various cut-off values for fibrosis and cirrhosis, only increasing age (odds ratio (OR) 1.09 (95% confidence interval (CI), 1.05-1.14 per year increment)), ALT (OR 1.01 (95% CI, 1.002-1.011), per unit increment) and HCV genotype 3 compared to genotype 1 (OR 2.40 (95% CI, 1.19-4.81), were consistently associated with cirrhosis (TE>17.1 kPa).

CONCLUSIONS

Age, ALT and infection with HCV genotype 3 were associated with cirrhosis assessed by TE. However, IL28B genotype was not an independent predictor of fibrosis in our study.

Evaluation of a hepatitis C virus (HCV) antigen assay for routine HCV screening among men who have sex with men infected with HIV

BACKGROUND

For detection of early HCV infection and reinfection, commercial HCV-RNA tests are available. However, these tests are relatively time-consuming and expensive. A commercially available test that may supplement current screening methods, targets the HCV core protein.

METHODS

During five waves of anonymous surveys at the Amsterdam STI clinic between 2009-2012, all HIV-infected MSM (N=439) were tested for HCV-antibodies (AxSYM HCV 3.0, Abbott), and HCV-RNA (TMA Versant, Siemens). To evaluate the potential value of the ARCHITECT HCV antigen (HCV-Ag) assay (Abbott), all HCV-RNA-positive sera (N=31) were tested with this assay, as well as two HIV-infected HCV-RNA-negative controls. In addition, all included samples were tested for alanine aminotransferase (ALT).

RESULTS

Among 439 HIV-infected MSM, 31 (7.1%) tested positive for HCV-RNA; the HCV-Ag assay showed concordant positive results for 31/31 (100%). A substantial number of MSM, i.e., 5/31 (16.1%), had detectable HCV-RNA but were HCV-seronegative at the time of screening and were presumed to have been recently infected. Concordant HCV-RNA-negative results were obtained in 57/60 control-samples. Specificity was 95.0% (95% CI: 86.1-99.0). The detection limit was between 3.0 and 3.7 Log10 IU/mL, irrespective of HCV genotype/subtype. ALT concentrations were elevated (i.e.,>40 U/L) in 9/31 (29.0%) HCV-RNA positive MSM, including 1/5 (20.0%) MSM with recent HCV-infection.

CONCLUSIONS

The HCV-Ag assay proved a valuable screening tool for detection of active HCV infection among HIV-infected MSM with and without anti-HCV. Adding ALT to current screening methods would improve case finding marginally. We therefore recommend implementation of routine HCV-Ag screening for populations at risk for HCV-(re)infection.

Modeling HCV disease in animals: virology, immunology and pathogenesis of HCV and GBV-B infections

Hepatitis C virus (HCV) infection has become a global public health burden costing billions of dollars in health care annually. Even with rapidly advancing scientific technologies this disease still poses a significant threat due to a lack of vaccines and affordable treatment options. The immune correlates of protection and predisposing factors toward chronicity remain major obstacles to development of HCV vaccines and immunotherapeutics due, at least in part, to lack of a tangible infection animal model. This review discusses the currently available animal models for HCV disease with a primary focus on GB virus B (GBV-B) infection of New World primates that recapitulates the dual Hepacivirus phenotypes of acute viral clearance and chronic pathologic disease. HCV and GBV-B are also closely phylogenetically related and advances in characterization of the immune systems of New World primates have already led to the use of this model for drug testing and vaccine trials. Herein, we discuss the benefits and caveats of the GBV-B infection model and discuss potential avenues for future development of novel vaccines and immunotherapies.

Nationwide experience of treatment with protease inhibitors in chronic hepatitis C patients in Denmark: identification of viral resistance mutations

Background and Aims

The first standard of care in treatment of chronic HCV genotype 1 infection involving directly acting antivirals was protease inhibitors telaprevir or boceprevir combined with pegylated-interferon and ribavirin (triple therapy). Phase III studies include highly selected patients. Thus, treatment response and development of viral resistance during triple therapy in a routine clinical setting needs to be determined. The aims of this study were to investigate treatment outcome and identify sequence variations after triple therapy in patients with chronic HCV genotype 1 infection in a routine clinical setting.

Methods

80 patients, who initiated and completed triple therapy in Denmark between May 2011 and November 2012, were included. Demographic data and treatment response were obtained from the Danish Database for Hepatitis B and C. Direct sequencing and clonal analysis of the RT-PCR amplified NS3 protease were performed in patients without cure following triple therapy.

Results

38 (47%) of the patients achieved cure, 15 (19%) discontinued treatment due to adverse events and remained infected, and 27 (34%) experienced relapse or treatment failure of whom 15 of 21 analyzed patients had well-described protease inhibitor resistance variants detected. Most frequently detected protease variants were V36M and/or R155K, and V36M, in patients with genotype 1a and 1b infection, respectively.

Conclusions

The cure rate after triple therapy in a routine clinical setting was 47%, which is substantially lower than in clinical trials. Resistance variants towards protease inhibitors were seen in 71% of patients failing therapy indicating that resistance could have an important role in treatment response.

A complete molecular biology assay for hepatitis C virus detection, quantification and genotyping

INTRODUCTION

Molecular biology procedures to detect, genotype and quantify hepatitis C virus (HCV) RNA in clinical samples have been extensively described. Routine commercial methods for each specific purpose (detection, quantification and genotyping) are also available, all of which are typically based on polymerase chain reaction (PCR) targeting the HCV 5' untranslated region (5'UTR). This study was performed to develop and validate a complete serial laboratory assay that combines real-time nested reverse transcription-polymerase chain reaction (RT-PCR) and restriction fragment length polymorphism (RFLP) techniques for the complete molecular analysis of HCV (detection, genotyping and viral load) in clinical samples.

METHODS

Published HCV sequences were compared to select specific primers, probe and restriction enzyme sites. An original real-time nested RT-PCR-RFLP assay was then developed and validated to detect, genotype and quantify HCV in plasma samples.

RESULTS

The real-time nested RT-PCR data were linear and reproducible for HCV analysis in clinical samples. High correlations (> 0.97) were observed between samples with different viral loads and the corresponding read cycle (Ct - Cycle threshold), and this part of the assay had a wide dynamic range of analysis. Additionally, HCV genotypes 1, 2 and 3 were successfully distinguished using the RFLP method.

CONCLUSIONS

A complete serial molecular assay was developed and validated for HCV detection, quantification and genotyping.

Signatures of protective memory immune responses during hepatitis C virus reinfection

BACKGROUND & AIMS

Development of a vaccine against hepatitis C virus (HCV) has been hindered by our limited understanding of immune correlates of protection during real-life exposure to the virus. We studied the immune response during HCV reinfection.

METHODS

We analyzed blood samples from participants in the Montreal Acute Hepatitis C Injection Drug User Cohort Study who were reinfected with HCV from 2009 to 2012. Five patients spontaneously resolved their second infection and 4 developed chronic infections. We monitored the phenotypic and functional dynamics of HCV-specific memory T cell responses in all subjects during natural re-exposure and re-infection.

RESULTS

Populations of CD4(+) and CD8(+) T cells with HCV-specific polyfunctional memory were expanded in all 5 individuals who resolved 2 successive HCV infections. We detected CD127(hi) HCV-specific memory CD8(+) T cells before reinfection regardless of a subject's ability to clear subsequent infections. Protection against viral persistence was associated with the expansion of a CD127(neg), PD1(lo) effector memory T cells at the peak of the response. We also observed broadening of T-cell response, indicating generation of de novo T-cell responses. The 4 individuals who failed to clear their subsequent infection had limited expansion of HCV-specific CD4(+) and CD8(+) memory T cells and expressed variable levels of the exhaustion marker PD1 on HCV-specific CD8(+) T cells. Dominant epitope regions of HCV strains isolated from patients with persistent reinfection had sequence variations that were not recognized by the pre-existing memory T cells.

CONCLUSIONS

Protection from persistent HCV reinfection depends on the magnitude, breadth, and quality of the HCV-specific memory T-cell response. Sequence homology among viruses and ability of T cells to recognize multiple strains of HCV are critical determinants of protective memory.

Hepatitis C virus infection in the human immunodeficiency virus infected patient

Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) share the same transmission routes; therefore, coinfection is frequent. An estimated 5-10 million individuals alone in the western world are infected with both viruses. The majority of people acquire HCV by injection drug use and, to a lesser extent, through blood transfusion and blood products. Recently, there has been an increase in HCV infections among men who have sex with men. In the context of effective antiretroviral treatment, liver-related deaths are now more common than Acquired Immune Deficiency Syndrome-related deaths among HIV-HCV coinfected individuals. Morbidity and mortality rates from chronic HCV infection will increase because the infection incidence peaked in the mid-1980s and because liver disease progresses slowly and is clinically silent to cirrhosis and end-stage-liver disease over a 15-20 year time period for 15%-20% of chronically infected individuals. HCV treatment has rapidly changed with the development of new direct-acting antiviral agents; therefore, cure rates have greatly improved because the new treatment regimens target different parts of the HCV life cycle. In this review, we focus on the epidemiology, diagnosis and the natural course of HCV as well as current and future strategies for HCV therapy in the context of HIV-HCV coinfection in the western world.

Hepatitis C virus (HCV) antibody dynamics following acute HCV infection and reinfection among HIV-infected men who have sex with men

BACKGROUND

A decline of hepatitis C virus (HCV) antibody titers (anti-HCV), ultimately resulting in seroreversion, has been reported following clearance of viremia in both acute and chronic HCV infection. However, frequency of seroreversion remains unknown in human immunodeficiency virus (HIV)/HCV-coinfected patients. We describe anti-HCV dynamics among HIV-infected men who have sex with men (MSM) following acute HCV infection and reinfection.

METHODS

Primary acute HCV infection was assumed when a subject was anti-HCV negative prior to the first positive HCV RNA test. Anti-HCV was measured at least annually in 63 HIV-infected MSM, with a median follow-up of 4.0 years (interquartile range [IQR], 2.5-5.7 years). Time from HCV infection to seroconversion, and from seroconversion to seroreversion, was estimated using the Kaplan-Meier method. Longitudinal anti-HCV patterns were studied using a random-effects model to adjust for repeated measures.

RESULTS

Median time from HCV infection to seroconversion was 74 days (IQR, 47-125 days). Subjects who cleared HCV RNA (n = 36) showed a significant decrease in anti-HCV levels (P < .001). Among 31 subjects with sustained virologic response (SVR), anti-HCV became undetectable during follow-up in 8; cumulative incidence of seroreversion within 3 years after seroconversion was 37% (95% confidence interval, 18%-66%). Eighteen subjects became reinfected during follow-up; this coincided with a subsequent increase in anti-HCV reactivity.

CONCLUSIONS

A decline of anti-HCV reactivity was associated with HCV RNA clearance. Seroreversion was very common following SVR. Upon reinfection, anti-HCV levels increased again. Monitoring anti-HCV levels might therefore be an effective alternative for diagnosis of HCV reinfection.

The genetic diversity and evolutionary history of hepatitis C virus in Vietnam

Vietnam has a unique history in association with foreign countries, which may have resulted in multiple introductions of the alien HCV strains to mix with those indigenous ones. In this study, we characterized the HCV sequences in Core-E1 and NS5B regions from 236 Vietnamese individuals. We identified multiple HCV lineages; 6a, 6 e, 6h, 6k, 6l, 6 o, 6p, and two novel variants may represent the indigenous strains; 1a was probably introduced from the US; 1b and 2a possibly originated in East Asia; while 2i, 2j, and 2m were likely brought by French explorers. We inferred the evolutionary history for four major subtypes: 1a, 1b, 6a, and 6 e. The obtained Bayesian Skyline Plots (BSPs) consistently showed the rapid HCV population growth from 1955 to 1963 until 1984 or after, corresponding to the era of the Vietnam War. We also estimated HCV growth rates and reconstructed phylogeographic trees for comparing subtypes 1a, 1b, and HCV-2.

Phylogeography and epidemic history of hepatitis C virus genotype 4 in Africa

HCV genotype 4 is prevalent in many African countries, yet little is known about the genotype׳s epidemic history on the continent. We present a comprehensive study of the molecular epidemiology of genotype 4. To address the deficit of data from the Democratic Republic of the Congo (DRC) we PCR amplified 60 new HCV isolates from the DRC, resulting in 33 core- and 48 NS5B-region sequences. Our data, together with genotype 4 database sequences, were analysed using Bayesian phylogenetic approaches. We find three well-supported intra-genotypic lineages and estimate that the genotype 4 common ancestor existed around 1733 (1650-1805). We show that genotype 4 originated in central Africa and that multiple lineages have been exported to north Africa since ~1850, including subtype 4a which dominates the epidemic in Egypt. We speculate on the causes of the historical intra-continental spread of genotype 4, including population movements during World War 2.

Nine additional complete genome sequences of HCV genotype 6 from Vietnam including new subtypes 6xb and 6xc

We completely sequenced nine HCV-6 variants from Vietnam. They are grouped into six lineages beyond the 24 assigned subtypes, 6a-6xa, and 14 unclassified lineages that have been recently described with full-length genomes. Co-analysis with reference sequences in the NS5B region identified additional 22 such lineages, which made the total taxonomic number of HCV-6 increased to 66 that might be recognized at the subtype level. Because two of these six lineages revealed in this study each had >3 epidemiologically unlinked isolates identified, we proposed to assign them new subtypes 6xb and 6xc in following the eXtended format recently recommended in the expanded HCV nomenclature.

Performance comparison of the versant HCV genotype 2.0 assay (LiPA) and the abbott realtime HCV genotype II assay for detecting hepatitis C virus genotype 6

The Versant HCV genotype 2.0 assay (line probe assay [LiPA] 2.0), based on reverse hybridization, and the Abbott Realtime HCV genotype II assay (Realtime II), based on genotype-specific real-time PCR, have been widely used to analyze hepatitis C virus (HCV) genotypes. However, their performances for detecting HCV genotype 6 infections have not been well studied. Here, we analyzed genotype 6 in 63 samples from the China HCV Genotyping Study that were originally identified as genotype 6 using the LiPA 2.0. The genotyping results were confirmed by nonstructural 5B (NS5B) or core sequence phylogenetic analysis. A total of 57 samples were confirmed to be genotype 6 (51 genotype 6a, 5 genotype 6n, and 1 genotype 6e). Four samples identified as a mixture of genotypes 6 and 4 by the LiPA 2.0 were confirmed to be genotype 3b. The remaining two samples classified as genotype 6 by the LiPA 2.0 were confirmed to be genotype 1b, which were intergenotypic recombinants and excluded from further comparison. In 57 genotype 6 samples detected using the Realtime II version 2.00 assay, 47 genotype 6a samples were identified as genotype 6, one 6e sample was misclassified as genotype 1, and four 6a and five 6n samples yielded indeterminate results. Nine nucleotide profiles in the 5' untranslated region affected the performances of both assays. Therefore, our analysis shows that both assays have limitations in identifying HCV genotype 6. The LiPA 2.0 cannot distinguish some 3b samples from genotype 6 samples. The Realtime II assay fails to identify some 6a and all non-6a subtypes, and it misclassifies genotype 6e as genotype 1.

Origin of hepatitis C virus genotype 3 in Africa as estimated through an evolutionary analysis of the full-length genomes of nine subtypes, including the newly sequenced 3d and 3e

We characterized the full-length genomes of nine hepatitis C virus genotype 3 (HCV-3) isolates: QC7, QC8, QC9, QC10, QC34, QC88, NE145, NE274 and 811. To the best of our knowledge, NE274 and NE145 were the first full-length genomes for confirming the provisionally assigned subtypes 3d and 3e, respectively, whereas 811 represented the first HCV-3 isolate that had its extreme 3' UTR terminus sequenced. Based on these full-length genomes, together with 42 references representing eight assigned subtypes and an unclassified variant of HCV-3, and 10 sequences of six other genotypes, a timescaled phylogenetic tree was reconstructed after an evolutionary analysis using a coalescent Bayesian procedure. The results indicated that subtypes 3a, 3d and 3e formed a subset with a common ancestor dated to ~202.89 [95% highest posterior density (HPD): 160.11, 264.6] years ago. The analysis of all of the HCV-3 sequences as a single lineage resulted in the dating of the divergence time to ~457.81 (95% HPD: 350.62, 587.53) years ago, whereas the common ancestor of all of the seven HCV genotypes dated to ~780.86 (95% HPD: 592.15, 1021.34) years ago. As subtype 3h and the unclassified variant were relatives, and represented the oldest HCV-3 lineages with origins in Africa and the Middle East, these findings may indicate the ancestral origin of HCV-3 in Africa. We speculate that the ancestral HCV-3 strains may have been brought to South Asia from Africa by land and/or across the sea to result in its indigenous circulation in that region. The spread was estimated to have occurred in the era after Vasco da Gama had completed his expeditions by sailing along the eastern coast of Africa to India. However, before this era, Arabians had practised slave trading from Africa to the Middle East and South Asia for centuries, which may have mediated the earliest spread of HCV-3.

Full-length genomes of 16 hepatitis C virus genotype 1 isolates representing subtypes 1c, 1d, 1e, 1g, 1h, 1i, 1j and 1k, and two new subtypes 1m and 1n, and four unclassified variants reveal ancestral relationships among subtypes

We characterized the full-length genomes of 16 distinct hepatitis C virus genotype 1 (HCV-1) isolates. Among them, four represented the first full-length genomes for subtypes 1d (QC103), 1i (QC181), 1j (QC329) and 1k (QC82), and another four corresponded to subtypes 1c (QC165), 1g (QC78), 1h (QC156) and 1e (QC172). Both QC196 and QC87 were assigned into a new subtype 1m, and QC113 and QC74 into another new subtype 1n. The remaining four (QC60, QC316, QC152 and QC180) did not classify among the established subtypes and corresponded to four new lineages. Subtypes 1j, 1k, 1m, 1n and the unclassified isolate QC60 were identified in Haitian immigrants. In the updated HCV nomenclature of 2005, a total of 12 subtypes of HCV-1 were designated. Including the data from the present study, all but subtype 1f now have their full-length genomes defined. Further analysis of partial NS5B sequences available in GenBank denoted a total of 21 unclassified lineages, indicating the taxonomic complexity of HCV-1. Among them, six have had their full-length genomes characterized. Based on the available full-length genome sequences, a timescale phylogenetic tree was reconstructed which estimated important time points in the evolution of HCV-1. It revealed that subtype 1a diverged from its nearest relatives 135 years ago and subtype 1b diverged from its nearest relatives 112 years ago. When subtypes 1a, 1j, 1k, 1m, 1n and six close relatives (all but one from Haitian immigrants) were considered as a whole, the divergence time was 176 years ago. This diversification was concurrent with the time period when the transatlantic slave trade was active. When taking all the HCV-1 isolates as a single lineage, the divergence time was 326 years ago. This analysis suggested the existence of a recent common ancestor for subtype 1a and the Haitian variants; a co-origin for subtypes 1b, 1i and 1d was also implied.

Characteristics of HCV co-infection among HIV infected individuals from an area with high risk of blood-borne infections in central China

OBJECTIVE

Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) co-infection has been proved to be a growing public health concern. The prevalence and genotypic pattern vary with geographic locations. Limited information is available to date with regard to HCV genotype and its clinical implications among those former commercial blood donor communities. The aims of this study were to genetically define the HCV genotype and associated clinical characteristics of HIV/HCV co-infected patients from a region with commercial blood donation history in central China.

METHODS

A cross sectional study, including 164 HIV infected subjects, was conducted in Shanxi province central China. Serum samples were collected and HCV antibody testing, AST and ALT testing were performed. Seropositive samples were further subjected to RT-PCR followed by direct sequence coupled with phylogenetic analysis of Core-E1 and NS5B regions performed in comparison with known reference genotypes.

FINDINGS

A total of 139 subjects were HCV antibody positive. Genotype could be determined for 88 isolates. Phylogenetic analysis revealed that the predominant circulating subtype was HCV 1b (65.9%), followed by HCV 2a (34.1%). The HCV viral load in the subjects infected with HIV1b was significantly higher than those infected with HCV 2a (P = 0.006). No significant difference for HCV RNA level was detected between ART status, CD4+ cell count level and HIV RNA level. Serum AST and ALT level were likely to increase with HCV RNA level, although no significance was observed. Those who had conducted commercial donation later than 1991 (OR 3.43, 95% CI: 1.12-10.48) and had a short duration of donation (OR 0.35, 95% CI: 0.13-0.96) were more likely to be infected with HCV 1b.

CONCLUSION

These results suggest that HCV subtype 1b predominates in this population, and the impact of HIV status and ART on HCV disease progression is not significantly correlated.

Tools for the diagnosis of hepatitis C virus infection and hepatic fibrosis staging

Hepatitis C virus (HCV) infection represents a major public health issue. Hepatitis C can be cured by therapy, but many infected individuals are unaware of their status. Effective HCV screening, fast diagnosis and characterization, and hepatic fibrosis staging are highly relevant for controlling transmission, treating infected patients and, consequently, avoiding end-stage liver disease. Exposure to HCV can be determined with high sensitivity and specificity with currently available third generation serology assays. Additionally, the use of point-of-care tests can increase HCV screening opportunities. However, active HCV infection must be confirmed by direct diagnosis methods. Additionally, HCV genotyping is required prior to starting any treatment. Increasingly, high-volume clinical laboratories use different types of automated platforms, which have simplified sample processing, reduced hands-on-time, minimized contamination risks and human error and ensured full traceability of results. Significant advances have also been made in the field of fibrosis stage assessment with the development of non-invasive methods, such as imaging techniques and serum-based tests. However, no single test is currently available that is able to completely replace liver biopsy. This review focuses on approved commercial tools used to diagnose HCV infection and the recommended hepatic fibrosis staging tests.

Genetic variability of the core protein in hepatitis C virus genotype 4 in Saudi Arabian patients and its implication on pegylated interferon and ribavirin therapy

Background

Hepatitis C virus (HCV) shows a remarkable genetic diversity, contributing to its high persistence and varied susceptibilities to antiviral treatment. Previous studies have reported that the substitution of amino acids in the HCV subgenotype 1b core protein in infected patients is associated with a poor response to pegylated interferon and ribavirin (PEG-IFN/RBV) combined therapy.

Objectives

Because the role of the core protein in HCV genotype 4 infections is unclear, we aimed in this study to compare the full-length core protein sequences of HCV genotype 4 between Saudi patients who responded (SVR) and did not respond (non-SVR) to PEG-IFN/RBV therapy.

Study design

Direct sequencing of the full-length core protein and bioinformatics sequence analysis were utilized.

Results

Our data revealed that there is a significant association between core protein mutations, particularly at position 70 (Arg⁷⁰Gln), and treatment outcome in HCV subgenotype 4d patients. However, HCV subgenotype 4a showed no significant association between core protein mutations and treatment outcome. In addition, amino acid residue at position 91 was well-conserved among studied patients where Cys⁹¹ is the dominant amino acid residue.

Conclusions

These findings provide a new insight into HCV genotype 4 among affected Saudi population where the knowledge of HCV core gene polymorphisms is inadequate.

Hepatitis C virus genotype 6: virology, epidemiology, genetic variation and clinical implication

Hepatitis C virus (HCV) is a serious public health problem affecting 170 million carriers worldwide. It is a leading cause of chronic hepatitis, cirrhosis, and liver cancer and is the primary cause for liver transplantation worldwide. HCV genotype 6 (HCV-6) is restricted to South China, South-East Asia, and it is also occasionally found in migrant patients from endemic countries. HCV-6 has considerable genetic diversity with 23 subtypes (a to w). Although direct sequencing followed by phylogenetic analysis is the gold standard for HCV-6 genotyping and subtyping, there are also now rapid genotyping tests available such as the reverse hybridization line probe assay (INNO-LiPA II; Innogenetics, Zwijnaarde, Belgium). HCV-6 patients present with similar clinical manifestations as patients infected with other genotypes. Based on current evidence, the optimal treatment duration of HCV-6 with pegylated interferon/ribavirin should be 48 wk, although a shortened treatment duration of 24 wk could be sufficient in patients with low pretreatment viral load who achieve rapid virological response. In addition, the development of direct-acting antiviral agents is ongoing, and they give high response rate when combined with standard therapy. Herein, we review the epidemiology, classification, diagnosis and treatment as it pertain to HCV-6.

Evaluation of the Abbott realtime HCV genotype II RUO (GT II) assay with reference to 5'UTR, core and NS5B sequencing

BACKGROUND

HCV genotyping is a critical tool for guiding initiation of therapy and selecting the most appropriate treatment regimen.

OBJECTIVE

To evaluate the concordance between the Abbott GT II assay and genotyping by sequencing subregions of the HCV 5'UTR, core and NS5B.

STUDY DESIGN

The Abbott assay was used to genotype 127 routine patient specimens and 35 patient specimens with unusual subtypes and mixed infection. Abbott results were compared to genotyping by 5'UTR, core and NS5B sequencing. Sequences were genotyped using the NCBI non-redundant database and the online genotyping tool COMET.

RESULTS

Among routine specimens, core/NS5B sequencing identified 93 genotype 1s, 13 genotype 2s, 15 genotype 3s, three genotype 4s, two genotype 6s and one recombinant specimen. Genotype calls by 5'UTR, core, NS5B sequencing and the Abbott assay were 97.6% concordant. Core/NS5B sequencing identified two discrepant samples as genotype 6 (subtypes 6l and 6u) while Abbott and 5'UTR sequencing identified these samples as genotype 1 with no subtype. The Abbott assay subtyped 91.4% of genotype 1 specimens. Among the 35 rare specimens, the Abbott assay inaccurately genotyped 3k, 6e, 6o, 6q and one genotype 4 variant; gave indeterminate results for 3g, 3h, 4r, 6m, 6n, and 6q specimens; and agreed with core/NS5B sequencing for mixed specimens.

CONCLUSIONS

The Abbott assay is an automated HCV genotyping method with improved accuracy over 5'UTR sequencing. Samples identified by the Abbott assay as genotype 1 with no subtype may be rare subtypes of other genotypes and thus require confirmation by another method.

Hepatitis C genotype distribution and homology among geographically disparate injecting drug users in Afghanistan

Hepatitis C virus (HCV) prevalence is high among injecting drug users in Afghanistan, but transmission dynamics are poorly understood. Samples from HCV-infected injecting drug users were sequenced to determine circulating genotypes and potential transmission linkages. Serum samples were obtained from injecting drug user participants in Hirat, Jalalabad, and Mazar-i-Sharif between 2006 and 2008 with reactive anti-HCV rapid tests. Specimens with detected HCV viremia were amplified and underwent sequence analysis. Of 113 samples evaluated, 25 samples (35.2%) were only typeable in NS5B, nine samples (12.7%) were only typeable in CE1, and 37 samples (52.1%) were genotyped in both regions. Of those with typeable HCV, all were Afghan males with a mean age of 31.1 (standard deviation [SD] ± 8.0) years and mean duration of injecting of 3.9 (SD ± 4.3) years. Most reported residence outside Afghanistan in the last decade (90.1%) and prior incarceration (76.8%). HCV genotypes detected were: 1a, (35.2%, n = 25), 3a (62.0%, n = 44), and 1b (2.8%, n = 2). Cluster formation was detected in NS5B and CE1 and were generally from within the same city. All participants within clusters reported being a refugee in Iran compared to 93.5% of those outside clusters. Only 22.2% (4/11) of those within clusters had been refugees in Pakistan and these four individuals had also been refugees in Iran. Predominance of genotype 3a and the association between HCV viremia and having been a refugee in Iran potentially reflects migration between Afghanistan and Iran among IDUs from Mazar-i-Sharif and Hirat and carry implications for harm reduction programs for this migratory population.

Hepatitis C virus reinfection following treatment among people who use drugs

Most new cases of hepatitis C virus (HCV) infections in the developed world are associated with injection drug use. However, treatment for people who inject drugs (PWID) is controversial, as successful treatment risks being followed by new infection. Reinfection after sustained virologic response has been reported, but is the risk so great that treatment should be withheld from this large HCV population? Preliminary evidence suggests that the reinfection incidence is low, but studies to date have been limited by small sample size and few cases of reinfection. In this review, we assess data from studies among PWID of HCV reinfection following treatment to give a reasonable estimate on how frequently reinfection appears and try to characterize those most at risk, The observation that spontaneous clearance of HCV reinfection following treatment occurs is suggestive of a partial protective immunity against persistent infection.

Epidemiology and treatment of hepatitis C genotypes 5 and 6

Chronic hepatitis C infection is a major global health problem. The WHO estimates the number of infected people worldwide to be approximately 170 million. The estimated number of hepatitis C virus (HCV)-infected people in Canada is approximately 250,000, with approximately 5000 Canadians newly infected each year. Based on the identification of genomic differences, HCV has been classified into six genotypes; genotype may influence the outcome of antiviral therapy. HCV genotypes 1, 2 and 3 are widely distributed throughout the world and have been the focus of the majority of epidemiological, natural course and treatment studies. Although HCV genotypes 5 and 6 are prevalent in certain geographical areas, they are studied less extensively. HCV genotypes 5 and 6 are uncommon in Canada and account for less than 5% of HCV-infected Canadians. However, immigration and travel can alter the epidemiology of these uncommon genotypes. The present article reviews and summarizes the available data regarding the epidemiology and treatment of HCV genotypes 5 and 6. Genotype 5 is endemic in the northern part of South Africa while genotype 6 is reported primarily in Asia. Available data show that 48 weeks of treatment with a combination of pegylated interferon and ribavirin lead to a higher sustained virological response compared with HCV genotypes 1 and 4. None of the approved direct-acting antiviral agents is currently recommended for the treatment of HCV genotypes 5 or 6.

Expanded classification of hepatitis C virus into 7 genotypes and 67 subtypes: updated criteria and genotype assignment web resource

The 2005 consensus proposal for the classification of hepatitis C virus (HCV) presented an agreed and uniform nomenclature for HCV variants and the criteria for their assignment into genotypes and subtypes. Since its publication, the available dataset of HCV sequences has vastly expanded through advancement in nucleotide sequencing technologies and an increasing focus on the role of HCV genetic variation in disease and treatment outcomes. The current study represents a major update to the previous consensus HCV classification, incorporating additional sequence information derived from over 1,300 (near-)complete genome sequences of HCV available on public databases in May 2013. Analysis resolved several nomenclature conflicts between genotype designations and using consensus criteria created a classification of HCV into seven confirmed genotypes and 67 subtypes. There are 21 additional complete coding region sequences of unassigned subtype. The study additionally describes the development of a Web resource hosted by the International Committee for Taxonomy of Viruses (ICTV) that maintains and regularly updates tables of reference isolates, accession numbers, and annotated alignments (http://talk.ictvonline.org/links/hcv/hcv-classification.htm). The Flaviviridae Study Group urges those who need to check or propose new genotypes or subtypes of HCV to contact the Study Group in advance of publication to avoid nomenclature conflicts appearing in the literature. While the criteria for assigning genotypes and subtypes remain unchanged from previous consensus proposals, changes are proposed in the assignment of provisional subtypes, subtype numbering beyond "w," and the nomenclature of intergenotypic recombinant.

CONCLUSION

This study represents an important reference point for the consensus classification of HCV variants that will be of value to researchers working in clinical and basic science fields.

Hepatitis C virus genotype diversity among intravenous drug users in Yunnan Province, Southwestern China

Background

Recently, high proportions (15.6%–98.7%) of intravenous drug users (IDUs) in China were found to be positive for hepatitis C virus (HCV). Yunnan Province is located in southwestern China and borders one of the world's most important opium-producing regions, thus it is an important drug trafficking route to other regions of China.

Methodology/Principal Findings

Here, we assessed 100 HCV-positive plasma samples from IDUs who were enrolled through the Kunming Center for Disease Control and Prevention in 2012. HCV C/E1 fragments were PCR-amplified and sequenced. We identified eight HCV subtypes (1a, 1b, 3a, 3b, 6a, 6n, 6u and 6v), of which genotype 6 was most predominant (frequency, 47%) followed by genotypes 3 (41%) and 1 (12%). HCV subtypes 6n (30%) and 3b (29%) were most common and were identified in 59% of the IDUs. We compared HCV genotypes among IDUs in Yunnan Province with those from other regions and found that the distribution patterns of HCV genotypes in Yunnan Province were similar to those in southern China, but different from those in eastern China. However, the distribution patterns of HCV subtypes varied among Yunnan Province and southern China, despite the shared similar genotypes. A comparison of the current data with those previously reported showed that the frequency of HCV genotype 6 increased from 25% to 47% within 5 years, especially subtypes 6a (5% to 15%) and 6n (11.2% to 30%). In contrast, the frequencies of subtypes 3b and 1b decreased by almost 50% within 5 years.

Conclusion/Significance

Our results provided further information to support the assertion that drug trafficking routes influence HCV transmission patterns among IDUs in Yunnan Province. The frequency of HCV genotypes and subtypes changed rapidly among IDUs in Yunnan Province and subtypes 6a and 6n may have originated in Vietnam and Myanmar, respectively.

Hepatitis C Virus NS5B Sequence-Based Genotyping Analysis of Patients From the Sharkia Governorate, Egypt

BACKGROUND

Chronic hepatitis C virus infection and its sequela are major health problems facing the Egyptian community. The high prevalence and spread rates of the disease require serious actions to stop or decrease these rates. Determination of HCV genotypes and subgenotypes adds significant knowledge about the epidemiology of the disease, and provides an added value in the decision making process of what strategy to follow and what therapy response to expect. The molecular epidemiology and genetic variability of HCV variants circulating in Egypt still need further analysis.

OBJECTIVES

The study was held to evaluate the genotype and subgenotype of the hepatitis c virus circulating in Sharkia as one of the large governorates of Egypt, which was not included in any study for genotyping of the virus before.

PATIENTS AND METHODS

The HCV molecular epidemiology in Sharkia governorate was studied using direct sequencing and further phylogenetic analysis of a partial NS5B region of the HCV genome from 63 patients. HCV genotype and subtype were successfully determined in 62 out of 63 patients.

RESULTS

The highest prevalent genotype was genotype 4a, which was found in 57 patients (92%) followed by 2 isolates (3%) with genotype 4o, 2 strains (3%) with genotype 1g and one isolate (2%) with genotype 4n.

CONCLUSIONS

This molecular epidemiology study revealed high prevalence of HCV genotype 4, subtype 4a among Egyptian patients residing in Sharkia governorate, Egypt.

Subtyping genotype 2 hepatitis C viruses from Tunisia: identification of two putative new subtypes

HCV variants were classified into six genotypes (1-6) subdivided into several subtypes with different geographic distribution worldwide. Previous studies conducted in Tunisia showed that genotype 1 counts for more than 80 % of circulating HCV genotypes and most of the isolates belong to subtype 1b. Genotype 2 comes in the second position, however, few sequences have been analyzed and published. In the present study, 89 isolates from Tunisian patients, typed as genotype 2 by the InnoLIPA commercial probe hybridization test, were sequenced in the NS5B and Core/E1 regions. All the isolates, clustered with the genotype 2 reference sequences, in the NS5B and in the Core/E1 region and the phylogenetic analyses in the two genomic regions were perfectly concordant: subtype 2c was the most frequent (58 out of 89, 65.1 %) and few isolates belonged to subtypes 2k(n = 10), 2i(n = 5), and 2b(n = 1). Fifteen isolates did not match with any of the reference sequences representing the genotype 2 subtypes, identified up-to-date. They divided into 2 separate clusters with high bootstrap values in both genomic regions. This study shows perfect concordance between the NS5B and the Core/E1 region suggesting that any of the two regions can be used for genotyping and that intergenotypic and intragenotypic recombinants are not very frequent, at least for HCV isolates from genotype 2. The present study also shows a predominance of subtype 2c among genotype 2 HCV isolates circulating in Tunisia, the co-circulation of minor subtypes (2k, 2i, and 2b) and proposes the possible existence of two other new subtypes.

Evolutionary dynamics of hepatitis C virus NS3 protease domain during and following treatment with narlaprevir, a potent NS3 protease inhibitor

Narlaprevir, a hepatitis C virus (HCV) NS3/4A serine protease inhibitor, has demonstrated robust antiviral activity in a placebo-controlled phase 1 study. To study evolutionary dynamics of resistant variants, the NS3 protease sequence was clonally analysed in thirty-two HCV genotype 1-infected patients following treatment with narlaprevir. Narlaprevir monotherapy was administered for one week (period 1) followed by narlaprevir/pegylated interferon-alpha-2b combination therapy with or without ritonavir (period 2) during two weeks, interrupted by a washout period of one month. Thereafter, all patients initiated pegylated interferon-alpha-2b/ribavirin combination therapy. Longitudinal clonal analysis was performed in those patients with NS3 mutations. After narlaprevir re-exposure, resistance-associated mutations at position V36, T54, R155 and A156 were detected in five patients in >95% of the clones. Narlaprevir retreatment resulted in a 2.58 and 5.06 log10 IU/mL viral load decline in patients with and without mutations, respectively (P=<0.01). After treatment, resistant variants were replaced with wild-type virus within 2-24 weeks in three patients. However, the R155K mutation was still observed 3.1 years after narlaprevir dosing in two patients in 5% and 45% of the viral population. Resistant variants could be detected early during treatment with narlaprevir. A slower viral load decline was observed in those patients with resistance-associated mutations detectable by direct population sequencing. These mutations disappeared within six months following treatment with the exception of R155K mutation, which persisted in two patients.

Molecular epidemiology and putative origin of hepatitis C virus in random volunteers from Argentina

AIM: To study the subtype prevalence and the phylogenetic relatedness of hepatitis C virus (HCV) sequences obtained from the Argentine general population, a large cohort of individuals was analyzed.

METHODS: Healthy Argentinian volunteers (n = 6251) from 12 provinces representing all geographical regions of the country were studied. All parents or legal guardians of individuals younger than 18 years provided informed written consent for participation. The corresponding written permission from all municipal authorities was obtained from each city or town where subjects were to be included. HCV RNA reverse transcription-polymerase chain reaction products were sequenced and phylogenetically analyzed. The 5’ untranslated region (5’UTR) was used for RNA detection and initial genotype classification. The NS5B polymerase region, encompassing nt 8262-8610, was used for subtyping.

RESULTS: An unexpectedly low prevalence of HCV infection in the general population (0.32%) was observed. Our data contrasted with previous studies that reported rates ranging from 1.5% to 2.5%, mainly performed in selected populations of blood donors or vulnerable groups. The latter values are in keeping with the prevalence reported by the 2007 Argentinian HCV Consensus (approximately 2%). HCV subtypes were distributed as follows: 1a (25%), 1b (25%), 2c (25%), 3a (5%), and 2j (5%). Two isolates ascribed either to genotype 1 (5%) or to genotype 3 (5%) by 5’UTR phylogenetic analysis could not be subtyped. Subtype 1a sequences comprised a highly homogeneous population and clustered with United States sequences. Genotype 1b sequences represented a heterogeneous population, suggesting that this genotype might have been introduced from different sources. Most subtype 2c sequences clustered close to the 2c reported from Italy and Southern France.

CONCLUSION: HCV has a low prevalence of 0.32% in the studied general population of Argentina. The pattern of HCV introduction and transmission in Argentina appears to be a consequence of multiple events and different for each subtype.

Hepatitis C virus subtyping based on sequencing of the C/E1 and NS5B genomic regions in comparison to a commercially available line probe assay

Hepatitis C virus (HCV) genotype determination is required in clinical practice to establish the dose and duration of antiviral treatment. Although subtype identification does not impact on current therapy this is changing with new specific inhibitors of HCV enzymes and functions which are becoming available worldwide. These new drugs may yield different antiviral responses and resistance profiles. Accurate classification of HCV genotype and subtype is therefore crucial. An "in-house" method was developed for improving HCV subtyping and the results were compared with a second-generation line probe assay (LiPA) used extensively in Portugal. Phylogenetic analysis was undertaken of the C/E1 and NS5B genomic regions of HCV isolated from 72 prisoners with chronic HCV infection and from reference samples. Although LiPA is considered to be a good method for genotyping, HCV was subtyped in only 47.2% of cases compared with 95.8% of cases by the "in-house" method. Molecular data for both C/E1 and NS5B regions were obtained in 88.9% of the samples. Two out of 23 cases of subtype 1a were misclassified as subtype 1b by LiPA. A putative recombinant like RF1_2k/1b, two potential inter-genotypic recombinants 1b/4a and 3a/4a, and also a potential intra-genotypic recombinant 2q/2k in C/E1 and 2k/2a in NS5B were also identified. The "in-house" method enabled HCV to be subtyped accurately with the detection, in some cases, of recombinant viruses or dual HCV infections. Near full-length genomic analysis to characterize these potential recombinant viruses is planned.

Infection frequency of hepatitis C virus and IL28B haplotypes in Papua New Guinea, Fiji, and Kiribati

It has been estimated that there are more than 60 million Hepatitis C virus (HCV) carriers in the World Health Organisation's Western Pacific region (WHO-WPR), where liver cancer is among the top three causes of cancer death. WHO and the US Centres for Disease Control and Prevention report the prevalence of HCV in the South Pacific islands (countries within the WHO-WPR) to be high (5-10% and >2% respectively). However, since HCV is not tested for in many of these countries, there is sparse data available to support this assertion. We screened ∼2000 apparently healthy individuals from Papua New Guinea, Fiji and Kiribati and found a sero-prevalence of 2.0%, 0.1% and 0%, respectively. All sero-positive samples tested negative for HCV RNA. Curious as to why all the sero-positive individuals were negative for HCV-RNA, we also screened them for the HCV protective IL28B SNP markers rs12979860 and rs8099917. All antibody-positive participants bar one had HCV protective haplotypes. Our results suggest that HCV is present in these Pacific island countries, albeit at a prevalence lower than previous estimates. As none of our participants had undergone antiviral treatment, and therefore must have cleared infection naturally, we hypothesise that genotypes 1 and/or 4 are circulating in South Pacific Island people and that these peoples are genetically predisposed to be more likely to spontaneous resolve HCV infection than to become chronic carriers.

Whole genome pyrosequencing of rare hepatitis C virus genotypes enhances subtype classification and identification of naturally occurring drug resistance variants

BACKGROUND

 Infection with hepatitis C virus (HCV) is a burgeoning worldwide public health problem, with 170 million infected individuals and an estimated 20 million deaths in the coming decades. While 6 main genotypes generally distinguish the global geographic diversity of HCV, a multitude of closely related subtypes within these genotypes are poorly defined and may influence clinical outcome and treatment options. Unfortunately, the paucity of genetic data from many of these subtypes makes time-consuming primer walking the limiting step for sequencing understudied subtypes.

METHODS

 Here we combined long-range polymerase chain reaction amplification with pyrosequencing for a rapid approach to generate the complete viral coding region of 31 samples representing poorly defined HCV subtypes.

RESULTS

 Phylogenetic classification based on full genome sequences validated previously identified HCV subtypes, identified a recombinant sequence, and identified a new distinct subtype of genotype 4. Unlike conventional sequencing methods, use of deep sequencing also facilitated characterization of minor drug resistance variants within these uncommon or, in some cases, previously uncharacterized HCV subtypes.

CONCLUSIONS

 These data aid in the classification of uncommon HCV subtypes while also providing a high-resolution view of viral diversity within infected patients, which may be relevant to the development of therapeutic regimens to minimize drug resistance.

Characterization of full-length hepatitis C virus sequences for subtypes 1e, 1h and 1l, and a novel variant revealed Cameroon as an area in origin for genotype 1

In this study, we characterized the full-length genome sequences of seven hepatitis C virus (HCV) isolates belonging to genotype 1. These represent the first complete genomes for HCV subtypes 1e, 1h, 1l, plus one novel variant that qualifies for a new but unassigned subtype. The genomes were characterized using 19-22 overlapping fragments. Each was 9400-9439 nt long and contained a single ORF encoding 3019-3020 amino acids. All viruses were isolated in the sera of seven patients residing in, or originating from, Cameroon. Predicted amino acid sequences were inspected and unique patterns of variation were noted. Phylogenetic analysis using full-length sequences provided evidence for nine genotype 1 subtypes, four of which are described for the first time here. Subsequent phylogenetic analysis of 141 partial NS5B sequences further differentiated 13 subtypes (1a-1m) and six additional unclassified lineages within genotype 1. As a result of this study, there are now seven HCV genotype 1 subtypes (1a-1c, 1e, 1g, 1h, 1l) and two unclassified genotype 1 lineages with full-length genomes characterized. Further analysis of 228 genotype 1 sequences from the HCV database with known countries is consistent with an African origin for genotype 1, and with the hypothesis of subsequent dissemination of some subtypes to Asia, Europe and the Americas.

Ever closer to a prophylactic vaccine for HCV

Introduction

With 3 – 4 million new infections occurring annually, hepatitis C virus (HCV) is a major global health problem. There is increasing evidence to suggest that HCV will be highly amenable to a vaccine approach, and despite advances in treatment, a vaccine remains the most cost-effective and realistic means to significantly reduce the worldwide mortality and morbidity associated with persistent HCV infection.

Areas covered

In this review we discuss immune responses to HCV during natural infection, and describe how they may inform vaccine design. We introduce the current candidate vaccines for HCV and compare how these fare against the expected requirements of an effective prophylactic HCV vaccine in relation to the breadth, functionality, magnitude and phenotype of the vaccine-induced immune response.

Expert opinion

Although the correlates of immune protection against HCV are not completely defined, we now have vaccine technologies capable of inducing HCV-specific adaptive immune responses to an order of magnitude that are associated with protection during natural infection. The challenge next is to i) establish well-characterised cohorts of people at risk of HCV infection for vaccine efficacy testing and ii) to better understand the correlates of protection in natural history studies. If these can be achieved, a vaccine against HCV appears a realistic goal.

Sequencing assays for failed genotyping with the versant hepatitis C virus genotype assay (LiPA), version 2.0

For optimal antiviral therapy, the hepatitis C virus (HCV) genotype needs to be determined, as it remains a strong predictor of sustained viral response. In this study, we assessed the number of HCV genotyping results that could not be determined using the commercially available line probe assay (LiPA) (Versant hepatitis C virus genotype 2.0 assay) in a large international panel of samples from 9,874 HCV-positive patients. In-house sequencing assays targeting the 5' untranslated region (UTR), core region, NS3 region, and NS5B region of the HCV genome and phylogenetic analyses were used to resolve these LiPA failures. Among all cases, the genotypes of 51 samples (0.52%) could not be determined with the LiPA. These undetermined results were observed more frequently among samples from non-European regions (mainly the Arabian Peninsula). The use of sequencing assays coupled with phylogenetic analysis provided reliable genotype results for 86% of the LiPA failures, which exhibited higher rates of genotypes 4, 5, and 6 than did LiPA-resolved genotypes. As expected, the 5' UTR was not sufficiently variable for clear discrimination between genotypes 1 and 6, but it also resulted in errors in classification of some genotype 3 and 4 cases using well-known Web-based BLAST programs. This study demonstrates the low frequency of genotyping failures with the Versant hepatitis C virus genotype 2.0 assay (LiPA) and also underlines the need for a complex combination of sequences and phylogenetic analyses in order to genotype these particular HCV strains correctly.

Validation of a solid-phase electrochemical array for genotyping hepatitis C virus

Hepatitis C viral infection is a major cause of progressive liver disease. HCV genotype is one of the most significant baseline predictors of response to HCV antiviral therapy. The objective was to evaluate an HCV genotyping method that targets the 5'-untranslated region (UTR) to detect genotypes/subtypes using the GenMark eSensor® XT-8 system. The HCV amplicon of major genotypes/subtypes from the Roche TaqMan® HCV assay served as a template for the nested PCR followed by a direct analysis on the XT-8 detection system. The assay was validated for limit of detection (LOD), specificity, accuracy and precision. The LOD determined was below 175 IU/ml for all the subtypes except 6ab. The genotypes detected using this assay were in concordance with the LiPA assay. The high performance characteristics (LOD, specificity, intra- and inter-assay precision, and accuracy), make this assay particularly well suited for clinical HCV genotyping in order to guide antiviral therapy.

Relationship of interferon-γ-inducible protein-10 kDa with viral response in patients with various heterogeneities of hepatitis C virus genotype-4

INTRODUCTION

The role of serum interferon-γ-inducible protein-10 kDa (IP-10) level in the treatment of chronic hepatitis C genotype-4 (HCV-4) and its various subtypes remains unknown. We aimed to study the impact of pretreatment IP-10 levels on the sustained viral response (SVR) in HCV-4 patients (n=64) undergoing peginterferon α-2a/ribavirin therapy.

PATIENTS AND METHODS

Pretreatment IP-10 levels and HCV-4 subtypes (4a=48.4%, 4d=39%, others=12.5%) were measured and correlated with treatment responses. Variables significantly associated with SVR on univariate analysis were included in a multivariate logistic regression model.

RESULTS

Patients with SVR had lower pretreatment IP-10 levels (462.4±282.7 vs. 840.1±490.6 pg/ml; P=0.002), but the levels were not significantly different in those with a rapid (P=0.245) or an early viral response (P=0.221). IP-10 levels were similar across all subtypes. The pretreatment level was significantly lower in subtype 4d patients with SVR (465.9±349.1) compared with non-SVR patients (904.9±532.1; P<0.001), but not when compared with genotype 4a patients (564.7±288.9 vs. 658.6±374.9, respectively; P=0.330). IP-10 levels [odds ratio (OR), 0.998; 95% confidence interval (CI): 0.996-0.999; P=0.006], low viremia (OR, 8.852; 95% CI: 1.244-63.03; P=0.029), and early viral response (OR, 4.162; 95% CI: 1.023-16.94; P=0.046) were independent predictors of SVR. Receiver operating characteristic curve analysis identified a threshold IP-10 level of 359 pg/ml (area under receiver operating characteristic curve, 0.737; sensitivity, 81.8%; specificity, 45.2; positive predictive value, 43.9%; negative predictive value, 82.6%) for SVR.

CONCLUSION

Pretreatment serum IP-10 level is a predictor for SVR in HCV-4-infected patients. The baseline IP-10 level is significantly lower in responders among HCV genotype-4d patients as compared with 4a patients.

Genome sequence of the hepatitis C virus subtype 6n isolated from malaysia

We report the full genome sequence of hepatitis C virus (HCV) subtype 6n from Kuala Lumpur, Malaysia. Phylogenetic analysis of the isolate 10MYKJ032 suggests that Southeast Asia might be the origin for the HCV subtype 6n and highlights the possible spread of this lineage from Southeast Asia to other regions.

Genetic and functional characterization of the N-terminal region of the hepatitis C virus NS2 protein

The hepatitis C virus (HCV) NS2 protein has dual roles within the HCV life cycle. While well characterized as an autoprotease that cleaves the NS2/NS3 junction, NS2, primarily via its N-terminal region, is also involved in virion morphogenesis. In order to map the determinants necessary for infectious virus production and gain further insight into the multiple points at which NS2 may impact this process, a detailed mutational analysis of residues spanning amino acids (aa) 1 to 92 was performed. Initial block mutagenesis (5 or 7 amino acid residues) in both bicistronic and monocistronic HCV cell culture-based (HCVcc) genomes revealed that all but two blocks had various levels of impaired infectious virus production. None of these mutations affected RNA replication, indicating that the N-terminal region of NS2 is not required for NS2-3 processing and replicase assembly. Fine mapping identified 29 critical residues that, when mutated, yielded at least a 1 log decrease in infectious virus titers. These mutants were characterized further with respect to release of extracellular HCV RNA and core, intracellular infectivity, thermal stability of virus particles, and NS2 interactions. While the most severely debilitated mutants were impaired early in the assembly process, which is in agreement with previous reports, others targeted later steps of virus production, most notably egress. Thus, in addition to participating in early steps in virion assembly, this comprehensive mutagenesis study suggests yet another role for NS2 in later steps in virus production.

Analysis of HCV quasispecies dynamic under selective pressure of combined therapy

Background

The quasispecies composition of Hepatitis C virus (HCV) could have important implications with regard to viral persistence and response to interferon-based therapy. The complete NS5A was analyzed to evaluate whether the composition of NS5A quasispecies of HCV 1a/1b is related to responsiveness to combined interferon pegylated (PEG-IFN) and ribavirin therapy.

Methods

Viral RNA was isolated from serum samples collected before, during and after treatment from virological sustained responder (SVR), non-responder (NR) and the end-of-treatment responder patients (ETR). NS5A region was amplified, cloned and sequenced. Six hundred and ninety full-length NS5A sequences were analyzed.

Results

This study provides evidence that lower nucleotide diversity of the NS5A region pre-therapy is associated with viral clearance. Analysis of samples of NRs and the ETRs time points showed that genetic diversity of populations tend to decrease over time. Post-therapy population of ETRs presented higher genetic distance from baseline probably due to the bottleneck phenomenon observed for those patients in the end of treatment. The viral effective population of those patients also showed a strong decrease after therapy. Otherwise, NRs demonstrated a continuous variation or stability of effective populations and genetic diversity over time that did not seem to be related to therapy. Phylogenetic relationships concerning complete NS5A sequences obtained from patients did not demonstrate clustering associated with specific response patterns. However, distinctive clustering of pre/post-therapy sequences was observed. In addition, the evolution of quasispecies over time was subjected to purifying or relaxed purifying selection. Codons 157 (P03), 182 and 440 (P42), 62 and 404 (P44) were found to be under positive selective pressure but it failed to be related to the therapy.

Conclusion

These results confirm the hypothesis that a relationship exists between NS5A heterogeneity and response to therapy in patients infected with chronic hepatitis C.

Phylogenetic analysis of isolated HCV strains from tunisian hemodialysis patients

The present study describes the strains of hepatitis C virus (HCV) isolated from Tunisian hemodialysis patients. Thirty-three HCV strains isolated from different dialysis centers in Tunis City were amplified by RT-PCR in a region of the NS5b gene, genotyped by sequencing, and compared to international sequences by phylogenetic analysis. The phylogenetic tree showed that 16 HCV isolates have been identified as subtype 4k (48.5%), 7 as unspecified HCV-4 subtype (21.2%), 5 as subtype 4a et 1b (each 15.2%). The analysis of this tree revealed that the HCV-1b strains were closely related to Anglo-Saxon and European isolates, while the HCV-4 isolates are genetically similar to Egyptian and African strains. Phylogenic analysis of 33 Tunisian isolates with international HCV strains on a region of the NS5b gene demonstrated that the subtype 4k submerged the Tunis city and a new subtype of HCV4 seems to be suspect in this area.

Hepatitis C genotype 4: genotypic diversity, epidemiological profile, and clinical relevance of subtypes in Saudi Arabia

BACKGROUND/AIM

Hepatitis C virus genotypes 4 (HCV-4) is the most prevalent genotype in Saudi Arabia, although it's various subtypes, mode and route of transmission remains unknown. The aim of this study was to analyze (i) the variability of the HCV-4 subtypes, the route and source of HCV transmission and (ii) the influence of HCV-4 subtypes on their therapeutic response.

PATIENTS AND METHODS

Sixty-four HCV-4 patients were analyzed retrospectively for the prevalence of various sub-genotypes and the possible mode of transmission, and it was correlated with their treatment response to pegylated interferon (PEG-IFN) α-2a and ribavirin therapy.

RESULTS

Positive history of blood or blood products transfusion was noted in 22 patients (34%), hemodialysis in 10 patients (15.6%), surgery in 7 patients (11%), and unknown etiology in 25 patients (39%). Prevalence of HCV-4 subtypes was 4a = 48.4% (31/64), 4d = 39% (25/64), 4n = 6.25% (4/64), and remaining combined (4m, 4l, 4r, 4o) 6.25% (4/64). No significant correlation between subtypes and the source of transmission was recognized ( P = 0.62). Sustained virological response in all HCV-4 patients was 64% (41/64), while in each subtypes separately it was 4a 77.4% (24/31), 4d 52% (13/25), and combined (4n, 4m, 4l, 4r, 4o) 62.5% (5/8) ( P = 0.046).

CONCLUSION

No obvious cause for the mode of HCV transmission was noted in majority of the patients. No significant correlation was observed between HCV-4 subtypes and the source of HCV infection. 4a and 4d subtypes were the most common in Saudi Arabia, and patients infected with 4a subtype responded significantly better to combination therapy than to 4d subtype.

Evidence for novel hepaciviruses in rodents

Hepatitis C virus (HCV) is among the most relevant causes of liver cirrhosis and hepatocellular carcinoma. Research is complicated by a lack of accessible small animal models. The systematic investigation of viruses of small mammals could guide efforts to establish such models, while providing insight into viral evolutionary biology. We have assembled the so-far largest collection of small-mammal samples from around the world, qualified to be screened for bloodborne viruses, including sera and organs from 4,770 rodents (41 species); and sera from 2,939 bats (51 species). Three highly divergent rodent hepacivirus clades were detected in 27 (1.8%) of 1,465 European bank voles (Myodes glareolus) and 10 (1.9%) of 518 South African four-striped mice (Rhabdomys pumilio). Bats showed anti-HCV immunoblot reactivities but no virus detection, although the genetic relatedness suggested by the serologic results should have enabled RNA detection using the broadly reactive PCR assays developed for this study. 210 horses and 858 cats and dogs were tested, yielding further horse-associated hepaciviruses but none in dogs or cats. The rodent viruses were equidistant to HCV, exceeding by far the diversity of HCV and the canine/equine hepaciviruses taken together. Five full genomes were sequenced, representing all viral lineages. Salient genome features and distance criteria supported classification of all viruses as hepaciviruses. Quantitative RT-PCR, RNA in-situ hybridisation, and histopathology suggested hepatic tropism with liver inflammation resembling hepatitis C. Recombinant serology for two distinct hepacivirus lineages in 97 bank voles identified seroprevalence rates of 8.3 and 12.4%, respectively. Antibodies in bank vole sera neither cross-reacted with HCV, nor the heterologous bank vole hepacivirus. Co-occurrence of RNA and antibodies was found in 3 of 57 PCR-positive bank vole sera (5.3%). Our data enable new hypotheses regarding HCV evolution and encourage efforts to develop rodent surrogate models for HCV.

Different HCV genotype distributions of HIV-infected individuals in Henan and Guangxi, China

Background

Due to shared transmission routes, hepatitis C virus (HCV) infection is highly prevalent among people infected with human immunodeficiency virus (HIV). Highly active antiretroviral therapy (HAART) is associated with hepatotoxicity, leading to the negative effects on patients with HIV/HCV co-infection. In order to provide valuable information for HCV management in this particular population, we investigated the HCV genotypes in HIV-infected individuals from Henan and Guangxi, the two provinces with the most HIV-infected cases in China.

Methods

Individuals, who acquired HIV infection through various risk routes, were recruited from Henan and Guangxi. Test of antibodies against HCV (anti-HCV) was conducted, and detection of HCV RNA was performed by PCR amplification. HCV subtypes were determined by direct sequencing of amplicons, followed by phylogenetic analysis.

Results

We recruited a total of 1,112 HIV-infected people in this present study. Anti-HCV was detected from 218 (50.1%) patients from Henan and 81 (12.0%) patients from Guangxi, respectively. The highest prevalence of HIV/HCV co-infection was observed from FBDs (former blood donors) (87.2%) in Henan and IDUs (intravenous drug users) (81.8%) in Guangxi, respectively. The seroprevalence rate of HCV among people with sexual contact was significantly higher in Henan than in Guangxi (18.7% vs. 3.5%, P<0.05). The positive rate of HCV RNA in Henan and Guangxi was 30.6% (133/435) and 11.2% (76/677), respectively. Moreover, we found that 20 anti-HCV negative samples were HCV positive by PCR amplification. HCV subtype 1b (52.7%) was predominant in Henan, followed by subtype 2a (41.9%). The most frequently detected subtypes in Guangxi were 6a (35.6%) and 3b (32.9%).

Conclusion

The HCV genotype distributions were different in HIV-infected people from Henan and Guangxi. HIV/HCV co-infection was not only linked to the transmission routes, but also associated with the geographic position.

Full-length genome sequences of five hepatitis C virus isolates representing subtypes 3g, 3h, 3i and 3k, and a unique genotype 3 variant

We characterized the full-length genomes of five distinct hepatitis C virus (HCV)-3 isolates. These represent the first complete genomes for subtypes 3g and 3h, the second such genomes for 3k and 3i, and of one novel variant presently not assigned to a subtype. Each genome was determined from 18-25 overlapping fragments. They had lengths of 9579-9660 nt and each contained a single ORF encoding 3020-3025 aa. They were isolated from five patients residing in Canada; four were of Asian origin and one was of Somali origin. Phylogenetic analysis using 64 partial NS5B sequences differentiated 10 assigned subtypes, 3a-3i and 3k, and two additional lineages within genotype 3. From the data of this study, HCV-3 full-length sequences are now available for six of the assigned subtypes and one unassigned. Our findings should add insights to HCV evolutionary studies and clinical applications.

Performance evaluation of the new Roche cobas AmpliPrep/cobas TaqMan HCV test, version 2.0, for detection and quantification of hepatitis C virus RNA

To evaluate the analytical performance and explore the clinical applicability of the new Roche cobas AmpliPrep/cobas TaqMan HCV test, v2.0 (CAP/CTM v2.0), a platform comparison was performed on panels and diagnostic samples with the Roche cobas AmpliPrep/cobas TaqMan HCV test (CAP/CTM v1.0), the Siemens Versant HCV RNA 3.0 branched DNA (bDNA) test, the Abbott m2000 RealTime HCV assay (Realtime assay), and the Siemens Versant HCV transcription-mediated amplification (TMA) test (TMA assay). The analytical performance of the CAP/CTM v2.0 on WHO and Acrometrix panels and clinical specimens of patients infected with HCV genotype 1, 2, 3, 4, 5, or 6 relative to that of the CAP/CTM v1.0 was significantly improved. In a qualitative comparison of the CAP/CTM v2.0 relative to the TMA assay on genotype 1 to 4 samples, the two tests proved to be almost equally sensitive. Response-guided therapy in one of five HCV genotype 4-infected patients previously tested with the CAP/CTM v1.0 would have significantly changed if tested with the CAP/CTM v2.0. In conclusion, the Roche CAP/CTM v2.0 has significantly better performance characteristics than the former CAP/CTM HCV v1.0 and the bDNA assay and performance characteristics comparable to those of the Realtime assay.

Molecular epidemiology of hepatitis C virus among different groups of people in the province of Fujian, China

Genotyping of hepatitis C virus (HCV) can provide valuable information for prognosis and treatment duration prediction. To explore the genetic diversity of HCV in Fujian Province, China, 112, 104 and 48 anti-HCV-positive serum samples were collected from volunteer blood donors, IDUs and patients, respectively, from Jan 2008 to Dec 2008 and were genotyped through sequence analysis, followed by phylogenetic analysis in the C/E1 and NS5B regions. Genotypes could be determined for 85.61 and 84.85 % of samples in the C/E1 and NS5B region, respectively. 6a was the most prevalent subtype, which accounted for 42.04 and 43.75 % in the C/E1 and NS5B region, respectively. Mixed infection and potential recombination were detected in this study. Kappa tests indicated that similar results were obtained by two genotyping methods targeting the C/E1 and NS5B regions. The differences in the main prevalent subtype between the three target groups suggest diversity of HCV prevalence in different populations.