Chronic hepatitis C: genotypes 4 to 9

Pharmacophore-Assisted Covalent Docking Identifies a Potential Covalent Inhibitor for Drug-Resistant Genotype 3 Variants of Hepatitis C Viral NS3/4A Serine Protease

The emergence of drug-resistance-inducing mutations in Hepatitis C virus (HCV) coupled with genotypic heterogeneity has made targeting NS3/4A serine protease difficult. In this work, we investigated the mutagenic variations in the binding pocket of Genotype 3 (G3) HCV NS3/4A and evaluated ligands for efficacious inhibition. We report mutations at 14 positions within the ligand-binding residues of HCV NS3/4A, including H57R and S139P within the catalytic triad. We then modelled each mutational variant for pharmacophore-based virtual screening (PBVS) followed by covalent docking towards identifying a potential covalent inhibitor, i.e., cpd-217. The binding stability of cpd-217 was then supported by molecular dynamic simulation followed by MM/GBSA binding free energy calculation. The free energy decomposition analysis indicated that the resistant mutants alter the HCV NS3/4A-ligand interaction, resulting in unbalanced energy distribution within the binding site, leading to drug resistance. Cpd-217 was identified as interacting with all NS3/4A G3 variants with significant covalent docking scores. In conclusion, cpd-217 emerges as a potential inhibitor of HCV NS3/4A G3 variants that warrants further in vitro and in vivo studies. This study provides a theoretical foundation for drug design and development targeting HCV G3 NS3/4A.

One-step real-time PCR assay for detection and quantification of RNA HCV to monitor patients under treatment in Brazil

The Brazilian Public Health Service provides freely αPEG-IFN to treat patients infected with HCV. The primary goal of HCV therapy is the long-term elimination of HCV from the blood to reduce the risk of HCV associated complications and death. Patient viremia affects the treatment duration and response, thus influencing clinical decisions. We developed a high-throughput method to perform the quantification of RNA hepatitis C virus (HCV) virus load in plasma samples to monitor patients under treatment. The method is based on a duplex detection, in a one-step real-time RT-PCR assay and it has been validated according to the rules established by the official Brazilian regulatory agency (ANVISA). This new method was compared to a commercial kit (Cobas/Taqman HCV Test v2.0 - Roche), showing virus load results with significant correlation between them (p = 0,012) using commercial and clinical panels. In addition, 611 samples from patients treated with peguilated alfa-interferon (αPEG-IFN) from different regions of Brazil were analyzed. Our one-step real-time RT-PCR assay demonstrated good performance in viral load measurement and in treatment course monitoring, with acceptable sensitivity and specificity values.

Genotype and genetic variation of HCV infections with low-risk factors in Putian coastal regions, China

Hepatitis C virus (HCV) infection is one of the leading causes of death and morbidity associated with liver disease. Risk factors identified for the transmission of HCV include contaminated blood products, intravenous drug use, body piercing, an infected mother at birth, sexual activity, and dental therapy, among others. However, the exact diversity of the HCV genotype and genetic variation among patients with low-risk factors is still unknown. In this study, we briefly described and analysed the genotype distribution and genetic variation of HCV infections with low-risk factors using molecular biology techniques. The results suggested that genotype 1b was predominant, followed by genotypes 2a and 1a. Genetic variations in the 5' UTR sequences of HCV were identified, including point mutations, deletions, and insertions. The frequency of genetic variations in 1b was higher than in 2a. This study provides considerable value for the prevention and treatment of liver disease caused by HCV among patients with low-risk factors and for the development of HCV diagnostic reagents and vaccines.

The NS4A Cofactor Dependent Enhancement of HCV NS3 Protease Activity Correlates with a 4D Geometrical Measure of the Catalytic Triad Region

We are developing a 4D computational methodology, based on 3D structure modeling and molecular dynamics simulation, to analyze the active site of HCV NS3 proteases, in relation to their catalytic activity. In our previous work, the 4D analyses of the interactions between the catalytic triad residues (His57, Asp81, and Ser139) yielded divergent, gradual and genotype-dependent, 4D conformational instability measures, which strongly correlate with the known disparate catalytic activities among genotypes. Here, the correlation of our 4D geometrical measure is extended to intra-genotypic alterations in NS3 protease activity, due to sequence variations in the NS4A activating cofactor. The correlation between the 4D measure and the enzymatic activity is qualitatively evident, which further validates our methodology, leading to the development of an accurate quantitative metric to predict protease activity in silico. The results suggest plausible “communication” pathways for conformational propagation from the activation subunit (the NS4A cofactor binding site) to the catalytic subunit (the catalytic triad). The results also strongly suggest that the well-sampled (via convergence quantification) structural dynamics are more connected to the divergent catalytic activity observed in HCV NS3 proteases than to rigid structures. The method could also be applicable to predict patients’ responses to interferon therapy and better understand the innate interferon activation pathway.

Current Treatment Options in Patients with Hepatitis C Virus Genotype 6

Approximately 3% of the world's population is chronically infected with hepatitis C virus (HCV). In some southeast Asian countries the prevalence of HCV (∼6%-7%) far exceeds that seen in the United States (1.8%). The lesser known HCV genotype 6 (HCV-6) is also common in patients from southeast Asia and the surrounding regions. Most data on direct-acting antivirals (DAAs) to date have been derived from clinical trials conducted in Western countries, where HCV-6 is rare. The standard of care for patients with HCV-6 is still pegylated interferon and ribavirin. However, data are emerging for several DAA combinations.

Viral hepatitis in hemodialysis: An update

Hepatitis outbreaks in hemodialysis (HD) patients and staff were reported in the late 1960s, and a number of hepatotropic viruses transmitted by blood and other body fluids have been identified. Hepatitis B virus (HBV) was the first significant hepatotropic virus to be identified in HD centers. HBV infection has been effectively controlled by active vaccination, screening of blood donors, the use of erythropoietin and segregation of HBV carriers. Hepatitis delta virus is a defective virus that can only infect HBV-positive individuals. Hepatitis C virus (HCV) is the most significant cause of non-A, non-B hepatitis and is mainly transmitted by blood transfusion. The introduction in 1990 of routine screening of blood donors for HCV contributed significantly to the control of HCV transmission. An effective HCV vaccine remains an unsolved challenge; however, pegylation of interferon-alfa has made it possible to treat HCV-positive dialysis patients. Unexplained sporadic outbreaks of hepatitis by the mid-1990s prompted the discovery of hepatitis G virus, hepatitis GB virus C and the TT virus. The vigilant observation of guidelines on universal precaution and regular virologic testing are the cornerstones of the effective control of chronic hepatitis in the setting of HD. Major recent advances in the viral diagnosis technology and the development of new oral, direct-acting antiviral agents allow early diagnosis and better therapeutic response. The current update will review the recent developments, controversies and new treatment of viral hepatitis in HD patients.

Current status and emerging challenges in the treatment of hepatitis C virus genotypes 4 to 6

Hepatitis C virus (HCV) genotypes 4, 5 and 6 are mainly present in Africa, the Middle East and Asia and they have been less extensively studied with respect to epidemiology, natural disease history and therapeutic endpoints. Response rates to a 48-wk combined peginterferon/ribavirin treatment range to 40%-69% for HCV 4, 55%-60% for HCV 5 and 60%-90% for HCV 6. Response-guided schedules are recommended to optimize the outcomes of peginterferon/ribavirin treatment in HCV 4 and, in form of preliminary data, for HCV 6, but no data are yet available to support such an individualization of therapy for HCV 5. Recently, the direct-acting antivirals (DAAs) with pan-genotypic activities simeprevir, sofosbuvir and daclatasvir have been recommended in triple regimens with peginterferon/ribavirin for the treatment of HCV genotypes 4 to 6 infections. In the future, DAA-based interferon-free therapies are awaited to drastically improve treatment outcomes in HCV. However, efforts to improve treatment outcomes with peginterferon/ribavirin should continue, as the HCV 4-6 infected population is mainly based in resource-limited settings with restricted access to the costly DAAs.

Meta-analysis: influence of host and viral factors in patients with chronic hepatitis C genotype 4 treated with pegylated interferon and ribavirin

The burden of hepatitis C virus genotype 4 (HCV-4) is high in Africa and East Mediterranean countries. Previous reports estimate sustained virologic response (SVR) rates in HCV-4 to be ∼20-70%. However, many of these studies are limited by different study designs and small sample sizes. Our aim was to evaluate treatment outcome and host/viral factors on SVR in HCV-4 patients treated with pegylated interferon and ribavirin (PEG IFN+RBV) in a systematic and quantitative manner. A comprehensive literature search in MEDLINE and EMBASE for 'genotype 4' was conducted in November 2013. Abstracts from American Association for the Study of Liver Diseases, Asian Pacific Study of the Liver, Digestive Disease Week, and European Association for the Study of the Liver in 2012/2013 were reviewed. Inclusion criteria were original studies with at least 25 treatment-naive HCV-4 patients treated with PEG IFN+RBV. Exclusion criteria were coinfection with HIV, hepatitis B virus, or other genotypes. Effect sizes were calculated using random-effects models. Heterogeneity was determined by Cochrane Q-test (P<0.05) and I statistic (>50%). We included 51 studies (11 102 HCV-4 patients) in the primary analysis. Pooled SVR was 53% [95% confidence interval (CI): 50-55%] (Q-statistic=269.20, P<0.05; I=81.43). On subgroup analyses, SVR was significantly associated with lower viral load, odds ratio (OR) 3.05 (CI: 1.80-5.17, P<0.001); mild fibrosis, OR 3.17 (CI: 2.19-4.59, P<0.001); and favorable IL28B polymorphisms, rs12979860 CC versus CT/TT, OR 4.70 (CI: 2.87-7.69, P<0.001), and rs8099917 TT versus GT/GG, OR 5.21 (CI: 2.31-11.73, P<0.001). HCV-4 patients treated with PEG IFN+RBV may expect SVR rates of ∼50%. Lower viral load, mild fibrosis, and favorable IL28B (rs12979860 CC and rs8099917 TT) are positively associated with SVR.

Do differences exist between chronic hepatitis C genotypes 2 and 3?

INTRODUCTION

Six genotypes of the hepatitis C virus (HCV) have been identified thus far, and their distribution is well defined. Genotype 1, which is the most prevalent worldwide, is always compared to genotypes 2 and 3, particularly in terms of treatment response. However, little is known about the differences between genotypes 2 and 3 because these genotypes are analyzed together in most studies. Therefore, the aim of this study was to evaluate differences in the clinical, epidemiological, laboratory, and histological parameters between HCV-2 and HCV-3.

METHODS

Patients with chronic hepatitis C infected with genotypes 2 and 3 were studied retrospectively and compared according to clinical, laboratory, and histological aspects. Hepatitis C virus-ribonucleic acid (HCV-RNA) was analyzed quantitatively by TaqMan® real-time PCR, and the HCV genotype was determined by sequencing the 5'-untranslated region.

RESULTS

A total of 306 patients with chronic HCV-2 (n=50) and HCV-3 (n = 256) were studied. Subtype 2b (n=17/50) and subtype 3a (n=244/256) were the most prevalent among patients infected with HCV-2 and HCV-3, respectively. The mean age was 47 ± 10 years, and there was a predominance of men in the group studied (61%). Comparative analysis between HCV-2 and HCV-3 showed a younger age (p=0.002), less prevalence of arterial hypertension (p=0.03), higher serum albumin levels (p=0.01), more advanced stage of liver fibrosis (p=0.03), and higher frequency of steatosis in patients with HCV-3 (p=0.001). After multivariate regression analysis, all the variables, except serum albumin, remained as variables associated with HCV-3 in the final model.

CONCLUSIONS

Clinical and histological differences exist between HCV-2 and HVC-3, which suggests the need for separate analyses of these genotypes.

Comparative molecular dynamics simulation of Hepatitis C Virus NS3/4A protease (Genotypes 1b, 3a and 4b) predicts conformational instability of the catalytic triad in drug resistant strains

The protease domain of the Hepatitis C Virus (HCV) nonstructural protein 3 (NS3) has been targeted for inhibition by several direct-acting antiviral drugs. This approach has had marked success to treat infections caused by HCV genotype 1 predominant in the USA, Europe, and Japan. However, genotypes 3 and 4, dominant in developing countries, are resistant to a number of these drugs and little progress has been made towards understanding the structural basis of their drug resistivity. We have previously developed a 4D computational methodology, based on 3D structure modeling and molecular dynamics simulation, to analyze the active sites of the NS3 proteases of HCV-1b and 4a in relation to their catalytic activity and drug susceptibility. Here, we improved the methodology, extended the analysis to include genotype 3a (predominant in South Asia including Pakistan), and compared the results of the three genotypes (1b, 3a and 4a). The 4D analyses of the interactions between the catalytic triad residues (His57, Asp81, and Ser139) indicate conformational instability of the catalytic site in HCV-3a and 4a compared to that of HCV-1b NS3 protease. The divergence is gradual and genotype-dependent, with HCV-1b being the most stable, HCV-4a being the most unstable and HCV-3a representing an intermediate state. These results suggest that the structural dynamics behavior, more than the rigid structure, could be related to the altered catalytic activity and drug susceptibility seen in NS3 proteases of HCV-3a and 4a.

My treatment approach to chronic hepatitis C virus

The treatment of chronic hepatitis C virus (HCV) is evolving rapidly. In 2014, the standard of care and new backbone of HCV treatment is the polymerase inhibitor sofosbuvir (SOF). Our treatment approach in patients with HCV genotype 1 is 12 weeks of SOF, peginterferon (PEGINF), and ribavirin (RBV). In patients with cirrhosis or extrahepatic manifestations of HCV who cannot tolerate PEGINF, we use 12 weeks of SOF and simeprevir. The latter is less costly and more effective than SOF and RBV for 24 weeks. Our treatment approach in all patients with genotype 2 is SOF and RBV for 12 weeks. Hepatitis C virus genotype 3 is now the most costly and difficult to cure. Our approach to treatment-naive patients with genotype 3 is SOF and RBV for 24 weeks. In patients who have previously undergone PEGINF and RBV treatment, we use PEGINF, SOF, and RBV for 12 weeks, which is equally if not more effective and less costly than SOF and RBV for 24 weeks. Patients with cirrhosis who cannot tolerate PEGINF should be treated for 24 weeks with SOF and RBV, although the sustained virologic response is suboptimal.

HCV F1/F2 patients: treat now or continue to wait

The treatment of chronic HCV is evolving rapidly. In 2014, three new oral antiviral agents, simeprevir, faldeprevir and sofosbuvir will become available for patients with HCV genotype 1. These agents have far less side effects than the first generation protease inhibitors telaprevir and boceprevir. Treatment will therefore be easier for patients to tolerate but still require peginterferon and ribavirin (PEGINF/RBV). The first IFN free therapy, sofosbuvir (SOF) and ribavirin (RBV), will also become available in 2014. This treatment is highly effective for patients with HCV genotype 2. However, SVR rates with SOF/RBV appear to be similar to that achieved with PEGINF/RBV in patients with HCV genotype 3. The first IFN-free all oral antiviral therapy combination for patients with HCV genotype 1 may be available late in 2014 or early 2015. The factors which should be considered when deciding whether to treat a patient with HCV now or to delay treatment until IFN free therapies are available is discussed.

Review article: the epidemiology and therapy of chronic hepatitis C genotypes 4, 5 and 6

BACKGROUND

The global burden of hepatitis C (HCV) infection is mostly found in Africa, the Middle East and Asia, where HCV genotypes 4, 5 and 6 are common. The literature on these genotypes is sparse and this synopsis will review characteristics of patients infected with these genotypes.

AIM

To review characteristics of patients infected with HCV genotypes 4, 5 and 6.

METHODS

PubMed search for 'hepatitis C' AND 'genotype 4', 'hepatitis C' AND 'genotype 5', and 'hepatitis C' AND 'genotype 6' was conducted and relevant articles were reviewed.

RESULTS

Intravenous drug use is generally responsible for HCV genotype 4 infection in developed countries, but unsafe medical practices cause most cases of HCV genotypes 4, 5 and 6 in endemic countries. The sustained virological response (SVR) rate for patients with HCV genotype 4 who receive pegylated interferon and ribavirin for 48 weeks ranges from 40% to 70% in various small studies. The SVR rate is in the 60-70% range for HCV genotype 5 and 70-80% range for HCV genotype 6 following 48 weeks with pegylated interferon and ribavirin. Preliminary data suggest that a shorter course of 24 weeks of pegylated interferon and ribavirin may be acceptable for HCV genotype 6, with an SVR rate of approximately 70%.

CONCLUSIONS

The current standard-of-care therapy for HCV genotypes 4, 5 and 6 is pegylated interferon and ribavirin for 48 weeks. A shorter course with 24 weeks of therapy may be considered for patients with genotype 6. Newer and much more effective therapies may be forthcoming in the next few years.

Fast, reliable and low cost user-developed protocol for detection, quantification and genotyping of hepatitis C virus

Early detection and genotyping of HCV infection is important for disease management. It is important to develop fast and cost-effective semi-automated techniques allowing an accurate and reproducible detection, quantification and genotyping of HCV. The proposed protocol includes a real-time RT-PCR assay for HCV detection/quantification and a type-specific one-tube RT-PCR assay for genotyping. Both assays detect genotypes 1-4 as intended. The limit of detection was 112IU/ml for the real-time assay and 600±278IU/ml (mean±SD) for the genotyping assay. Concordance between the real-time assay and AMPLICOR HCV v2.0 test was 100%. The real-time assay has wide linear dynamic range of detection and quantification and excellent reproducibility with 2% and 0.75% coefficients of variations, for inter- and intra-assays, respectively. The observed correlation with AMPLICOR HCV Monitor v2.0 kit was linear with the correlation coefficient of 0.988. The diagnostic specificity and sensitivity of the genotyping assay, tested on 102 samples, was 100% and 95%, respectively. The overall procedure of HCV diagnosis is completed within 6h in a closed system with minor contamination risk. In addition to being fast and cost-effective, this approach is reproducible and avoids post-PCR enzymatic and hybridization steps while detecting and genotyping HCV with high clinical sensitivity.

Prevalence of hepatitis C virus genotypes in risk groups in the Republic of Macedonia: a 5 years survey

The prevalence of hepatitis C virus (HCV) genotypes depends on geographical location. HCV genotyping is important for epidemiological investigations and treatment management. The aim of this study was to determine the HCV genotype prevalence in the most prominent risk groups in the Republic of Macedonia in the last 5 years and to evaluate its association with patient's age, gender, and mode of transmission. A total of 1,167 HCV positive patients, divided into three risk groups (intravenous drug use, chronic hemodialysis, and other risk factor), were genotyped using an in-house ASO hybridization method with genotype-specific oligonucleotide probes. The genotypes 1, 2, and 3 were present with 52.2%, 0.6%, and 47.0%, respectively. Genotype 1 was most prevalent in hemodialysis (89.0%) and other risk factor group (53.8%). It was found associated independently with hemodialysis, age >40 and female gender. Genotype 3 predominated in intravenous drug users (64.0%) and was associated significantly also with age ≤40 and male gender. Multivariable logistic regression analysis pointed out hemodialysis (P < 0.0001, Exp (B) = 12.0) as a positive predictor factor for genotype 1 and age ≤40 (P = 0.021, Exp (B) = 1.8) and intravenous drug use (P < 0.0001, Exp (B) = 8.4) as a positive predictor factors for genotype 3. In conclusion, the main transmission route of HCV infection in the Republic of Macedonia is intravenous drug use, followed by hemodialysis. HCV genotypes 1 and 3 dominate in these two most prominent risk groups in the Republic of Macedonia.

Prevalence of IL-28B and ITPA genotypes in Chinese Han population infected persistently with hepatitis C virus genotype 6 or HCV-1

The geographic distribution, demographics, epidemiology, host factors, and clinical characteristics of persistent HCV-6 infection in China need further characterization. This multicenter study enrolled 63 patients with persistent HCV-6 infection and 63 patients with persistent HCV-1 infection as controls. Blood biochemistry, quantitation of HCV RNA levels, and identification of host IL-28B genotypes (rs12979860, rs8099917, and rs12980275) and ITPA genotype (rs1127354) were performed to estimate potential variability in host factors that may affect response to treatment. The mean HCV-6 RNA level (3.8E6 IU/ml) was significantly higher than that in patients infected with HCV-1 (1.7E6 IU/ml; P < 0.001). Patients persistently infected with HCV-6 had a high prevalence of IL-28B rs12979860 CC genotype (92.1%), rs8099917 TT genotype (93.7%), and rs12980275 AA genotype (90.5%). Their prevalence in patients infected with HCV-1 was only modestly lower (82.5%, 84.1%, and 82.5%, respectively; P > 0.05). The inosine triphosphate pyrophosphatase (ITPA) SNP rs1127354 CC genotype was present in 66.7% of patients infected with HCV-6, comparable to that of patients infected with HCV-1 (65.1%; P > 0.05). There were no differences in the liver function, proportion of hepatic cirrhosis patients or patients with increased serum glucose between these two groups. Persistent HCV-6 infection in Chinese Han is found mainly in the southern China. Chinese Han with chronic HCV-1 or HCV-6 infection have IL-28B genotypes, suggesting responsiveness to interferon-based pharmacotherapy. Most patients (67%) possess the ITPA genotype associated with susceptibility to ribavirin-induced hemolysis. The routes of transmission for HCV-6 genotype were more diversified than HCV-1 genotype. The outbreak of HCV-6 infection through blood transfusion progressed faster than HCV-1.

A 3D structural model and dynamics of hepatitis C virus NS3/4A protease (genotype 4a, strain ED43) suggest conformational instability of the catalytic triad: implications in catalysis and drug resistivity

Egypt has the highest prevalence of hepatitis C virus (HCV) infection worldwide with a frequency of 15%. More than 90% of these infections are due to genotype 4, and the subtype 4a (HCV-4a) predominates. Moreover, due to the increased mobility of people, HCV-4a has recently spread to several European countries. The protease domain of the HCV nonstructural protein 3 (NS3) has been targeted for inhibition by several drugs. This approach has had marked success in inhibiting genotype 1 (HCV-1), the predominant genotype in the USA, Europe, and Japan. However, HCV-4a was found to resist inhibition by a number of these drugs, and little progress has been made to understand the structural basis of its drug resistivity. As a step forward, we sequenced the NS3 HCV-4a protease gene (strain ED43) and subsequently built a 3D structural model threaded through a template crystal structure of HCV-1b NS3 protease. The model protease, HCV-4a, shares 83% sequence identity with the template protease, HCV-1b, and has nearly identical rigid structural features. Molecular dynamics simulations predict similar overall dynamics of the two proteases. However, local dynamics and 4D analysis of the interactions between the catalytic triad residues (His57, Asp81, and Ser139) indicate conformational instability of the catalytic site in HCV-4a NS3 protease. These results suggest that the divergent dynamics behavior, more than the rigid structure, could be related to the altered catalytic activity and drug resistivity seen in HCV-4a.

Age and gender distribution of hepatitis C virus genotypes in the metropolitan area of Naples

OBJECTIVE

To assess any time-related variations in the distribution of hepatitis C virus (HCV) genotypes in the metropolitan area of Naples, Italy.

METHODS

HCV genotypes were analysed in 255 HCV RNA-positive patients with chronic HCV infection, observed from 2009 to 2011, and compared with data pertaining to a sample of 176 HCV RNA-positive patients observed from 2006 to 2008.

RESULTS

In both periods of analysis, genotype 1b was predominant (51.8 and 48.3%, respectively), followed by genotype 2 (27.9 and 31.7%, respectively). These HCV genotypes were particularly prevalent in older patients, whereas genotypes 3a and 1a were observed more frequently in the younger population. Genotype 1b was particularly common in females compared to males in both study periods (39.3% of 89 males vs. 64.3% of 87 females in the 3-year period 2006-2008, p < 0.001; 41.5% of 118 males vs. 54.0% of 137 females in the period 2009-2011, p < 0.05). The prevalence of patients with genotype 1b in the age range 51-60 years was higher in the 2006-2008 period than in 2009-2011 (76.9 vs. 37.7%; p < 0.0005) and lower in the over 60 year olds (55.1 vs. 59.6%; p = 0.5).

CONCLUSION

Genotype 1b, historically the most prevalent in Italy, is still predominant; however, when comparing the two time periods, a cohort effect evidencing the increasing prevalence of genotype 1b among elderly patients was revealed.

Patients with HCV and F1 and F2 fibrosis stage: treat now or wait?

The current standard of care (SOC) for patients with chronic HCV genotype 1 is a combination of either boceprevir or telaprevir with peginterferon (PEG-IFN) and ribavirin (RBV). Although it is effective in a high percentage of patients, this treatment is associated with significant adverse events (AEs). The next generation of protease inhibitors, simeprevir and faldaprevir, will also be used with PEG-IFN/RBV. Interferon-free therapy with sofosbuvir appears promising and on the horizon for patients with genotypes 2 and 3, but may still be many years away for patients with HCV genotype 1. The factors which should be considered when deciding whether to treat a patient with HCV and mild fibrosis with the current SOC now, or to delay treatment until less toxic and/or more effective therapy is available is discussed.

Correlation of viral loads with HCV genotypes: higher levels of virus were revealed among blood donors infected with 6a strains

Background

Both HCV genotypes and viral loads are predictors of therapeutic outcomes among patients treated with α-interferon plus ribavirin; however, such correlation has only been studied for genotypes 1, 2, and 3 but not for genotype 6.

Methodology/Findings

299 voluntary blood donors were recruited who were HCV viremic. Their mean age was 31.8; the male/female ratio was 3.82 (225/59). The viral loads of HCV were measured using the COBAS AmpliPrep/COBAS TaqMan test (CAP/CTM) while HCV genotypes were determined by direct sequencing the partial NS5B region. HCV genotypes 1, 2, 3, and 6 were determined in 48.9%, 8.7%, 12.3%, and 30.1% of the donors, respectively, and the levels of mean viral loads in genotype 1 and 6 significantly higher than that of 2 and 3 (P<0.001). As a whole, the viral loads in male donors were higher than in female (P = 0.006). Moreover, the donors' gender and HCV genotypes are independently correlated with the measured viral loads.

Conclusion

HCV genotype 1 and 6 had significantly higher viral loads than genotype 2 and 3.

HCV genotype determination in monoinfected and HIV co-infected patients in Cuba

With the aim to characterize the HCV genotype distribution in Cuba, sera were collected from two subgroups: HCV-monoinfected and HCV/HIV co-infected patients. A combination of reverse transcription-PCR using genotype-specific primers, restriction fragment length polymorphism and sequencing was used to determine the genotype of 84 samples. Seventy-nine (94%) showed single infections (10 [12%] were genotype 1a and 69 [82%] genotype 1b) and 5 (6%) samples corresponded to mixed infections (2 [2%] with genotypes 1a/3a and 1 sample [1%] each with 1b/3a, 1b/4a and 1a/1b/3a). HCV/HIV co-infected subjects had a higher frequency of mixed infections (p=0.08), infection with genotype 3a (p=0.18) and for the first time genotype 4a was found. There was no association of any demographic characteristics with any specific genotype although HCV/HIV co-infected patients showed a tendency to have mixed genotypes in those older than 45 years of age (p=0.11). Phylogenetic analysis showed that HCV isolates clustered with subtypes 1b (n=15, maximal genetic distance 2.51%) and 1a (n=2, maximal genetic distance 0.35%). This report presents the prevalence of HCV genotypes in monoinfected and HIV co-infected patients, mixed HCV infections in HCV/HIV co-infected men who have sex with men with high-risk sexual practices and for the first time identifies that the uncommon genotype 4a can be present in a patient co-infected with HIV.

New insights into hepatitis C virus infection in the tribal-dominant part of Northeast India

Northeast India is known for the demographic heterogeneity of its tribal population, but there is no information about hepatitis C virus infection and associated risk factors. Anti-HCV was measured, HCV-RNA was detected based on the 5' UTR-core region, and genotyping was done by direct sequencing of the NS5b region. Antibodies to HCV were found in 13.7 % of the samples tested (96 out of 700), while HCV-RNA was positive in 73 % of the samples (70 out of 96) and in 5 out of 385 cases of occult HCV infection. Genotypes 1 to 4 were found respectively in 14.6, 7.3, 20, 30.8 %, and genotype 6 in 13.6 %, of the 75 HCV isolates. In acute viral hepatitis (AVH), the most prevalent genotype was 2a (28.6 %), while it was 4a (28 %) in chronic hepatitis C (CHC) and 29.4 % in cirrhosis. Males were more prone than females to HCV infection, and the highest numbers of cases of HCV infection were recorded in the age group of 40-49 years. The major risk factors were intravenous drug abuse (IVDU) (34.6 %), multiple sexual partners (20 %) and contact with professional barbers (38.6 %). The seroprevalence of HCV in Northeast India is higher than in the rest of India. This study highlights the fact that geographical variations occur with respect to HCV genotypes, which could influence the course and progress of different type of liver diseases seen in India.

Elevated serum osteopontin levels in chronic hepatitis C virus infection: association with autoimmune rheumatologic manifestations

Owing to the suggested role of osteopontin (OPN) in inflammation, autoimmunity and fibrosis, we investigated their serum concentrations in chronic hepatitis C virus (HCV) infected patients with and without autoimmune manifestations and correlated those levels to clinical manifestations and the histological severity of hepatic fibrosis. A total of 70 chronic HCV-infected patients (35 with and 35 without autoimmune rheumatic manifestations‏) were compared with 35 healthy volunteers matched for age and gender. Epidemiological, clinical, immunochemical and virological data were prospectively collected. OPN serum levels were assessed by an Enzyme Linked Immunosorbant Assay. The mean serum OPN levels were higher in HCV patients with autoimmune rheumatologic manifestations and in patients without; than that for the normal controls (p = 0.000). The mean OPN values progressively increased by increasing severity of liver fibrosis (p = 0.009). Multivariate analysis revealed that the presence of rheumatologic manifestations had the highest predictive value (b = 7.141, Beta = 0.414, p = 0.000) followed by liver fibrosis (b = 4.522, Beta = 0.444, p = 0.000) on the variation of OPN levels in our HCV patients. Among the group of patients with HCV and rheumatologic involvement, OPN serum levels were higher in patients with positive cryoglobulin and rheumatoid factor than in those without, and with systemic vasculitis than in those without. Correlation analysis didn't reveal any statistical significance of OPN with age, serum albumin, aminotransferases and viral load. Our data suggests OPN as a promising marker for HCV associated autoimmune rheumatologic involvement, particularly with regard to development of vasculitis and cryoglobinemia. In addition, it could serve as a biomarker to evaluate the severity of liver damages in HCV infected subjects.

APASL consensus statements and management algorithms for hepatitis C virus infection

The Asian Pacific Association for the Study of the Liver (APASL) convened an international working party on the "APASL Consensus Statements and Management Algorithms for Hepatitis C Virus Infection" in December, 2010, in order to revise "Asian Pacific Association for the Study of the Liver consensus statements on the diagnosis, management and treatment of hepatitis C virus infection (J Gastroenterol Hepatol 22:615-633, 2007)". The working party consisted of expert hepatologists from the Asian-Pacific region gathered at Makuhari, Chiba, Japan on 19 December 2010. New data were presented, discussed and debated to draft a revision. Participants of the consensus meeting assessed the quality of cited studies. Finalized recommendations are presented in this review.

Systematic review: epidemiology of hepatitis C genotype 6 and its management

BACKGROUND

Hepatitis C virus (HCV) genotype 6 is common among patients from Southeast Asia and the surrounding regions, where HCV prevalence is also high. HCV genotype 6 has great genetic diversity and different response to antiviral therapy compared with the more commonly known genotype 1.

AIM

Our goal was to provide a systematic review of the current literature on the epidemiology, classification and treatment of HCV genotype 6.

METHODS

A search using PubMed for 'hepatitis C' AND 'genotype 6' produced a total of 47 articles, of which 33 articles were found to be relevant and included in this review. Additional articles were identified using the reference lists of these 33 primary articles.

RESULTS

The prevalence of HCV genotype 6 is estimated to be as high as 50% in some regions of Southeast Asia with demonstrated significance among intravenous drug users and thalassemia major patients. Although previous line probe assays may have misclassified HCV genotype 6 as genotype 1, newer line probe assays can more accurately and reliably determine HCV genotype. Patients infected with HCV genotype 6 respond better to interferon-based therapy compared with those infected with genotype 1, although patient baseline clinical characteristics and side effect profiles are similar between HCV genotype 6 and other HCV genotypes.

CONCLUSIONS

Future studies should seek to clarify issues regarding early predictors for treatment response in patients with HCV genotype 6, and the impact of ethnic and genotypic factors to treatment response in HCV genotype 6 patients.

Chronic hepatitis C

The goal of antiviral therapy for patients with chronic hepatitis C virus (HCV) infection is to attain a sustained virologic response (SVR), which is defined as undetectable serum HCV-RNA levels at 6 months after the cessation of treatment. Major improvements in antiviral therapy for chronic hepatitis C have occurred in the past decade. The addition of ribavirin to interferon-alfa therapy and the introduction of pegylated interferon (PEG-IFN) have substantially improved SVR rates in patients with chronic hepatitis C. The optimization of HCV therapy with PEG-IFN and ribavirin continues to evolve. Studies are ongoing that use viral kinetics to tailor therapy to an individual's antiviral response and determine the ideal length of treatment to maximize the chance of SVR. Improved SVR can be achieved with new specific inhibitors that target the HCV NS3/4A protease and the NS5B polymerase. Several long-term follow-up studies have shown that SVR, when achieved, is associated with a very low risk of virologic relapse. Furthermore, antiviral therapy can reduce the morbidity and mortality rates associated with chronic hepatitis C by reducing fibrosis progression, the incidence of cirrhosis, and hepatocellular carcinoma.

The interaction between HCV and nuclear receptor-mediated pathways

Hepatitis C virus (HCV) is presently the leading indication for liver transplantation in Western countries. Treatment for HCV infection includes a combination of pegylated interferon and ribavirin, which produces highly variable response rates. This reflects the lack of information regarding the roles of host and viral components during viral pathogenesis. Vital processes regulated by the liver, including metabolism, lipid homeostasis, cellular proliferation, and the immune response, are known to be systematically dysregulated as a result of persistent HCV infection. Nuclear receptors and their ligands are recognized as indispensable regulators of liver homeostasis. Pathways mediated by the nuclear receptor superfamily have been shown to be profoundly disrupted during HCV infection, leading to an increased importance in elucidating the exact nature of this complex relationship. Expanded understanding of the role of nuclear receptors in HCV infection may therefore be an essential step in the search for a more universally effective treatment.

Response to pegylated interferon and ribavirin in Asian American patients with chronic hepatitis C genotypes 1 vs 2/3 vs 6

Chronic hepatitis C is generally underappreciated in Asian Americans, and most pivotal studies were conducted in western countries and only included a small numbers of Asian patients. Our goal was to examine and compare treatment outcomes in these patients with genotypes 1 vs 2/3 vs 6. We performed a retrospective cohort study of 167 consecutive treatment-naïve Asian American patients treated with pegylated interferon (PEG IFN) plus ribavirin (RBV) at two community clinics in Northern California from 12/00 to 1/08. Primary outcome was sustained virological response rate by intention-to-treat analysis. The overall completion rate was 76%, and treatment adherence (completion of ≥ 75-80% PEG IFN + RBV dose for ≥ 75-80% of intended duration) was 74%. Significant depression was noted in only 4% of patients. Sustained virologic response in patients with genotype 6 treated for 48 weeks was similar to that seen in those with genotype 2/3 (74%vs 75%, P = 0.89) and significantly higher than those with genotype 1 (74%vs 49%, P = 0.016). On multivariate analysis inclusive of sex, age, body mass index (≤ 25 vs > 25) and viral load, only treatment adherence and genotype (2/3 and 6 treated for 48 weeks) were found to be significant predictors of sustained virologic response. We conclude that significant depression is rare in Asian American patients (4%). Patients with genotype 6 treated for 48 weeks appear to have a similar treatment response rate as patients with genotype 2/3 and a significantly higher response rate than those with genotype 1.

Risk factors, genotype 6 prevalence, and clinical characteristics of chronic hepatitis C in Southeast Asian Americans

PURPOSE

Although infection with hepatitis C virus (HCV) affects 32 million individuals from Southeast Asia, little is known about the mode of HCV acquisition and the epidemiology of chronic hepatitis C (CHC) in these individuals. Our goal was to examine risk factors for HCV acquisition, prevalence, and clinical characteristics of HCV genotype 6 compared with genotypes 1 and 2/3 in Southeast Asian (SEA) patients.

METHODS

We performed a cross-sectional study of 308 consecutive SEA Americans with CHC evaluated by five gastroenterologists from January 2000 to December 2008 at two community clinics in northern California via medical record review, using a case report form.

RESULTS

A significant proportion of patients (41%) could not recall any specific risk factors for HCV acquisition. The most commonly reported risk factor in patients who reported at least one risk factor was history of surgeries (34%), followed by blood transfusion (25%) and acupuncture (13%). Among patients with core sequence testing for HCV genotype (n = 181), the most common HCV genotypes were genotype 1 (42%) and genotype 6 (41%), followed by genotype 2/3 (17%). There were no major differences in the clinical and virological characteristics between the different genotype groups (1 vs. 2/3 vs. 6).

CONCLUSION

HCV genotype 6 is as common as genotype 1 in SEAs. Commonly known risk factors for HCV acquisition were not readily identifiable in a large proportion of SEA Americans (41%) and may not be useful in identifying at-risk individuals for HCV screening in this population.

Individualized treatment of chronic hepatitis C with pegylated interferon and ribavirin

Chronic infection with hepatitis C virus (HCV) is a major public health problem, with perhaps 180 million people infected worldwide. A significant proportion of these will eventually develop clinical complications, such as cirrhosis, liver decompensation and hepatocellular carcinoma. Sustained virological response (SVR) to antiviral therapy is associated with improvement in liver histology and survival free of liver-related complications. Great effort has been made to improve SVR rate by adapting the duration of therapy according to HCV genotype and to on-treatment response. Rapid virological response (RVR, undetectable HCV RNA at week 4) usually has a high positive predictive value for achieving SVR and early virological response (EVR, ≥ 2 log reduction or undetectable HCV RNA at week 12) exhibits a high negative predictive value for non-response. Individualized approach can improve cost-effectiveness of HCV antiviral therapy by reducing side effects and the costs of therapy associated with unnecessary exposure to treatment and through extending therapy for those with unfavorable features. This article summarizes recent data on strategies of individualized treatment in naïve patients with mono-infection by the different HCV genotypes. The management of common side effects, the impact of HCV infection on health-related quality of life and the potential applications of host genomics in HCV therapy are also briefly discussed.

The neglected hepatitis C virus genotypes 4, 5 and 6: an international consensus report

Abstract Hepatitis C virus (HCV) genotypes 4, 5 and 6 represent >20% of all HCV cases worldwide. HCV-4 is mainly seen in Egypt, where it represents 90% of all HCV cases. Antischistosomal therapy was the main cause of contamination there, followed by procedures performed by informal providers and traditional healers such as dental care, wound treatment, circumcision, deliveries, excision and scarification. It is also highly prevalent in sub-Saharan Africa and in the Middle East. In Europe, its prevalence has recently increased particularly among intravenous drug users and in immigrants. HCV-5 is mainly found in South Africa, where it represents 40% of all HCV genotypes, but four pockets of HCV-5 were found in France, Spain, Syria and Belgium and sporadic cases were found elsewhere. The mode of transmission is mainly iatrogenic and transfusion. HCV-6 is found in Hong Kong, Vietnam, Thailand and Myanmar and also in American and Australian from Asian origin. The response to treatment in HCV-4 is intermediate between HCV-1 and HCV-2 and HCV-3. A sustained viral response is achieved in 43-70% with pegylated interferon and ribavirin. It is higher in Egyptians than Europeans and Africans and is negatively related to insulin resistance and to the severity of fibrosis. It increases to >80% with 24 weeks of therapy only if a rapid virological response is achieved. In HCV-5, a sustained virological response is achieved in >60% with 48 weeks of therapy. HCV-6 is also considered an easy-to-treat genotype, leading to a response in 60-85% of cases.

Epidemiology of hepatitis B and C viruses: a global overview

This article reviews the prevalence, disease burden, genotype distribution, and transmission patterns of hepatitis B virus (HBV) and hepatitis C virus in the 6 World Health Organization regions. The global epidemiology of hepatitis B and C demonstrates a predominantly declining prevalence of the diseases. Improvement in the control of hepatitis B has been largely achieved with implementation of a more universal HBV vaccine program, although a large gap still remains in the effort toward global prevention of hepatitis B. The transmission of hepatitis C has been greatly impacted by mandatory screening of blood donors in most countries in the world, although intravenous drug use continues to be a major source of infection. Public education regarding the risks of exposure to infected paraphernalia as well as household items such as razors is necessary in the continuing effort to curb this disease.

Higher rate of sustained virologic response in chronic hepatitis C genotype 6 treated with 48 weeks versus 24 weeks of peginterferon plus ribavirin

OBJECTIVES

Infection with hepatitis C virus (HCV) genotype 6 is common in patients from parts of China and Southeast Asia. No study to date has examined the treatment response to peginterferon and ribavirin (PEG IFN + RBV) in these patients, or the effects of treatment duration on sustained virologic response (SVR) rates.

METHODS

We performed a retrospective study of 190 consecutive Asian-American patients who were diagnosed with HCV genotype 6 at a gastroenterology clinic in northern California between 2001 and 2004, 66 of whom were treatment-naïve and subsequently completed 24 wk of IFN + RBV or PEG IFN + RBV or 48 wk of PEG IFN + RBV therapy. The primary outcome was SVR.

RESULTS

There was no statistical difference in SVR of 31 patients treated with 24 wk of IFN + RBV and in 23 patients treated with 24 wk of PEG IFN + RBV (51.6%vs 39%, P= 0.363). The SVR in 12 patients treated with 48 wk of PEG IFN + RBV was significantly higher than that in those treated for only 24 wk (75%vs 39%, P= 0.044).

CONCLUSIONS

Treatment-eligible patients with HCV genotype 6 should be treated with a full course of 48 wk as tolerated. Larger prospective studies of patients with HCV genotype 6 are needed to confirm the optimal treatment duration with PEG IFN + RBV.

The emerging importance of chronic hepatitis C infection in Asian Americans

OBJECTIVES

To study the demographics, epidemiology, and natural history of chronic hepatitis C in Asian Americans.

METHODS

This retrospective survey describes 260 Asian Americans with chronic hepatitis C referred to one tertiary center.

RESULTS

Ninety-two percent of patients were born in Asia. Fifty-one percent reported a history of unsafe therapeutic injections, which was a risk factor only in those with exposure outside the United States (p < 0.0001). A history of transfusion was reported in 41% of patients and was more frequent in those with exposure within the Unites States (p < 0.0001). Only 3.8% reported a history of intravenous drug abuse, which was more frequent in those with exposure within the United States (p < 0.0001). Hepatitis C genotype 1 was detected in 64.2% of patients, genotype 2 in 18.3%, and genotype 6 in 11.3%. Genotype 1 had a significantly lower sustained virologic response rate (32.8%) to interferon treatment, compared with genotype 2 (77.8%) or 6 (69.2%). During a mean follow-up of 6 yr, 26 patients developed hepatocellular carcinoma (HCC). Logistic regression model revealed fibrosis stage 4 (odds ratio [OR] 8.87, 95% confidence interval [CI] 2.97-26.48, p < 0.0001), age at presentation (55 vs 35 yr--OR 3.45, 95% CI 1.22-9.75, p= 0.0194), and baseline albumin level (3.0 vs 4.0 mg/dL--OR 3.47, 95% CI 1.02-11.76, p= 0.0464) were independent predictive factors for HCC development.

CONCLUSIONS

Asian Americans with a history of unsafe therapeutic injections must be screened for chronic hepatitis C. Antiviral treatment should be initiated prior to development of cirrhosis. Surveillance for HCC must be routinely performed in cirrhosis patients.

Serum islet cell autoantibodies during interferon alpha treatment in patients with HCV-genotype 4 chronic hepatitis

Chronic hepatitis C virus (HCV) infection is a leading cause of end-stage liver disease worldwide and HCV genotype 4 (HCV4) is predominant in African and Middle Eastern countries. It is well established that interferon-a (IFNa) treatment for HCV may trigger serum autoantibodies against pancreatic islet cells (ICA) in a subgroup of patients. Available data on the incidence of ICA during IFNa therapy for chronic HCV4 infection are not conclusive. We investigated the appearance of ICA in 40 naïve Egyptian patients (38 males, 32 +/- 6 years) with histologically defined chronic HCV4 infection undergoing IFNa treatment at a dose of 9-million U/week for 24 weeks. Serum samples were collected at baseline and following IFNa therapy and ICA were detected using indirect immunofluorescence. Baseline evaluation indicated that 2/40 (5%) patients had detectable serum ICA. After the completion of the treatment scheme, 12/38 (32%) previously ICA negative patients became ICA positive; however, no patient developed impaired glucose tolerance (IGT) or diabetes during follow-up. In conclusion, we submit that IFNa treatment for chronic hepatitis C (CHC) may induce serum ICA in one-third of Egyptian patients with HCV4. These autoantibodies, however, do not lead to alterations in glucose metabolism.