NS3 protease polymorphisms and genetic barrier to drug resistance of distinct hepatitis C virus genotypes from worldwide treatment‐naïve subjects

Hepatitis C virus (HCV) NS3 protease inhibitors have been primarily designed against genotype 1, the one with the lowest response to dual therapy. However, less evidence of their efficacy on non‐1 genotypes is available, and any such information is mostly concentrated on genotypes 2‐4. This study evaluated HCV protease resistance profiles in the major six HCV genotypes and identified genetic barrier (GB) profiles to each available protease inhibitor across HCV strains from different locations worldwide. We obtained 15 099 HCV sequences from treatment‐naïve subjects retrieved at the Los Alamos HCV Sequence Database. The wild‐type codons of different HCV genotypes were used to analyse the smallest number of nucleotide substitution steps required for changing that codon to the closest one associated with drug resistance. The 36L and 175L RAVs were found as genetic signatures of genotypes 2‐5, while the 80K RAV was found in all genotype 5 sequences. Genotypes 4 and 6 showed a higher GB to RAV mutations conferring resistance to telaprevir, while genotypes 2‐5 presented baseline resistance to that drug, carrying the 36L mutation. Genotype 4 had a higher GB to simeprevir resistance, requiring three substitutions to acquire the 155K mutation. Subtype 1b showed a higher GB than subtype 1a to resistance for most PIs, with RAVs at codons 36 and 155. Geographic disparities were also found in frequencies of certain RAVs in genotypes 2 and 3. Under a scenario of unprecedented evolution of anti‐HCV direct‐acting agents, the genetic composition of the circulating HCV sequences should be evaluated worldwide to choose the most appropriate/feasible therapeutic schemes with the highest genetic barriers to resistance.     

The presence of resistance mutations to protease and polymerase inhibitors in Hepatitis C virus sequences from the Los Alamos databank

Several new direct‐acting antiviral (DAA) drugs are in development for chronic hepatitis C viral (HCV) infection, and NS3‐NS4A serine protease and the NS5B RNA‐dependent RNA polymerase have been the major targets. HCV variants displaying drug‐resistant phenotypes have been observed both in vitro and during clinical trials. Our aim was to characterize amino acid changes at positions previously associated with resistance in protease (NS3) and polymerase (NS5B) regions from treatment‐naïve HCV patients infected with genotypes 1a, 1b and 3a. All 1383 NS3 protease sequences (genotype 1a = 680, 1b = 498 and 3a = 205) and 806 NS5B polymerase sequences (genotypes 1a = 471, 1b = 329, 3a = 6) were collected from Los Alamos databank. Genotype 3a protease sequences showed the typical low‐level resistance mutation V36L. NS3 sequences from other genotypes presented mutations on positions 36, 39, 41, 43, 54, 80, 109, 155 and 168 in a frequency lower than 2%, except for the mutation Q80R found in 35% of genotype 1a isolates. Polymerase sequences from genotype 3a patients showed five typical mutations: L419I, I424V, I482L, V499A and S556G. Two positions presented high polymorphism in the NS5B region from genotype 1a (V499A) and genotype 1b (C316N) subjects. Our results demonstrated a natural profile of genotype 3a that can be associated with the pre‐existence of HCV variants resistant to first‐generation protease inhibitors and to non‐nucleoside polymerase inhibitors. Likewise, genotype 1b isolates and genotype 1a sequences exhibited pre‐existing mutations associated with resistance to Palm II and Thumb I polymerase inhibitors, respectively.     

HCV 3b亚型全长序列测定及基线耐药相关置换的分析

目的探讨二代测序法(NGS)在HCV 3b全长序列及基线耐药相关置换(RAS)检测中的应用。方法从1例2016年7月在广州血液中心献血的献血者(HCV RNA阳性)血浆中提取核酸,经序列非依赖性扩增后,构建测序文库并采用illumina Hiseq进行深度测序,然后通过生物信息学方法分析HCV全长序列、病毒基因分型以及针对直接抗病毒药物(DAA)的基线RAS。结果NGS获得8.4 Gb原始测序数据,序列数(reads)超过56 M。经生物信息学分析获得HCV全长序列,平均测序深度为488007,基因分型结果为3b亚型。病毒氨基酸序列里含有12个RAS,分别是NS3区域的Y56H、Q80K、Q80R、A156G,NS5A区域的M28G、Q/A30G、Q/A30K、L31F、L31M、Y93H,以及NS5B区域的S282T和V321A,其中位于NS5A区域的Q/A30K和L31M属于高丰度RAS(99.16%和98.37%),其余10个RAS丰度较低(<0.5%)。结论NGS用于HCV 3b亚型的全长序列检测和基因分型,最终鉴定出基线RAS,对于HCV 3b的流行病学研究和DAA治疗方案的制订有重要意义。     

In vitro resistance profile of hepatitis C virus NS5A inhibitor velpatasvir in genotypes 1 to 6

Velpatasvir is a pan‐genotypic hepatitis C virus (HCV) NS5A inhibitor, which is used with sofosbuvir for treatment of infection with HCV genotypes 1‐6. In vitro resistance studies were performed to characterize NS5A changes that might confer reduced velpatasvir susceptibility in vivo. Resistance selection studies using HCV replicon cells for subtypes 1a, 1b, 2a, 2b, 3a, 4a, 5a and 6a identified NS5A resistance‐associated substitutions (RASs) at nine positions, most often 28M/S/T, 31F/I/M/P/V and 93D/H/N/S. In subtype 1a, RASs were selected at positions 31 and/or 93, while in subtype 1b, replicons with two or more RASs at positions 31, 54 or 93 were selected. Y93H was selected in subtypes 1a, 1b, 2a, 3a and 4a. In subtype 5a or 6a, L31P or P32L/Q was selected, respectively. Velpatasvir susceptibility of 358 replicons from genotypes 1 to 6 containing one or more NS5A RASs was also evaluated. The majority (63%) of subtypes 1a and 1b single RAS‐containing replicons retained susceptibility to velpatasvir (<2.5‐fold change in EC₅₀). High levels of resistance to velpatasvir were observed for six single mutants in subtype 1a, including M28G, A92K, Y93H/N/R/W and for one mutant, A92K, in subtype 1b. Most single mutants in subtypes 2a, 2b, 3a, 4a and 5a displayed low levels of reduced velpatasvir susceptibility. High‐level resistance was observed for C92T and Y93H/N in subtype 2b, Y93H/S in 3a, and L31V and P32A/L/Q/R in 6a, and several double mutants in these subtypes. Overall, velpatasvir maintained activity against most common RASs that are known to confer resistance to first‐generation NS5A inhibitors.     

Genotype diversity of hepatitis C virus (HCV) in HCV‐associated liver disease patients in Indonesia

Background: Hepatitis C virus (HCV) genotype distribution in Indonesia has been reported. However, the identification of HCV genotype was based on 5′‐UTR or NS5B sequence. Aims: This study was aimed to observe HCV core sequence variation among HCV‐associated liver disease patients in Jakarta, and to analyse the HCV genotype diversity based on the core sequence. Methods: Sixty‐eight chronic hepatitis (CH), 48 liver cirrhosis (LC) and 34 hepatocellular carcinoma (HCC) were included in this study. HCV core variation was analysed by direct sequencing. Results: Alignment of HCV core sequences demonstrated that the core sequence was relatively varied among the genotype. Indeed, 237 bases of the core sequence could classify the HCV subtype; however, 236 bases failed to differentiate several subtypes. Based on 237 bases of the core sequences, the HCV strains were classified into genotypes 1 (subtypes 1a, 1b and 1c), 2 (subtypes 2a, 2e and 2f) and 3 (subtypes 3a and 3k). The HCV 1b (47.3%) was the most prevalent, followed by subtypes 1c (18.7%), 3k (10.7%), 2a (10.0%), 1a (6.7%), 2e (5.3%), 2f (0.7%) and 3a (0.7%). HCV 1b was the most common in all patients, and the prevalence increased with the severity of liver disease (36.8% in CH, 54.2% in LC and 58.8% in HCC). These results were similar to a previous report based on NS5B sequence analysis. Conclusion: Hepatitis C virus core sequence (237 bases) could identify the HCV subtype and the prevalence of HCV subtype based on core sequence was similar to those based on the NS5B region.     

Genotypic subtyping of hepatitis C virus

Four subtypes of hepatitis C virus (HCV), Pt(I), K1(II), K2a(III) and K2b(IV), have been suggested based on the nucleotide sequences of the non-structural (NS) 5 region. A fifth subtype from Japanese patients, Tr(V), which shows a less than 68% homology in nucleotide sequence when compared with other subtypes has been identified. A one-step method which enables a quick determination of subtype using polymerase chain reaction with a mixed primer set deduced from the sequence of each subtype has been developed. Using this technique, the subtypes of 418 out of 478 Japanese patients (87.4%) were determined. The incidence of each subtype in Japan was as follows: K1(II), 307 (73.4%); K2a(III), 74 (17.7%); K2b(IV), 28 (6.7%); and Tr(V), 3 (0.7%). This one-step subtyping technique should be useful for studying the epidemiology or biology of the HCV.     

Genotypes and multiple infections with hepatitis C virus in patients with haemophilia A in Japan

SUMMARY. Hepatitis C virus (HCV) RNA was tested for, and HCV genotypes determined, in 96 patients with haemophilia A in Japan. Of 88 patients aged ≥ 10 years, 74 (84%) were positive for HCV RNA at a frequency higher than that in patients aged less than 10 years (one of eight, 13% P <0.001). Genotype I/1a was detected in 30 (40%), II/1b in 12 (16%), III/2a in eight (11%), IV/2b in five (7%) and V/3a in 12 (16%); mixed infection with HCV of two different genotypes was identified in the remaining nine (12%). This distribution was markedly different from that in 767 Japanese HCV carriers without haemophilia, in whom II/1b accounted for the majority (68.7%), I/1a was rare (0.5%), V/3a was absent, and mixed infection was observed rarely (1.3%). Mixed infection was transient in all of the seven haemophilic patients who were followed for 1 to 7 years. One of them was infected with genotype II/ 1b and an unclassifiable genotype, which showed nucleotide sequence similarity to genotype 4c from Zaire (82% homology in the El gene) and to 4a from Egypt (91% homology in a part of the NS5b region). In this patient, HCV of genotype II/1b disappeared while that of group 4 survived during a 4-year observation period. These results indicate different epidemiology of HCV genotypes in Japanese haemophiliacs, attributable to HCV contaminating factor VIII imported in the past, and an increased opportunity in haemophiliacs for mixed infection with HCV of different genotypes.     

Replacement of hepatitis C virus genotype 1b by genotype 2 over a 10-year period in Venezuela

BACKGROUND: Changes in hepatitis C virus (HCV) genotype distribution with time have been reported in several countries. GOALS: To explore eventual changes in HCV genotype distribution in Venezuela over a 10 years period. STUDY: HCV genotype was determined by direct sequencing of the 5' noncoding region, in 236 isolates circulating in patients treated during years 2005 to 2006. Genotype distribution was compared with the one observed in 43 patients followed during years 1994 to 1996. RESULTS: The prevalence HCV genotype 1 and 2 was 70% and 26%, respectively, in patients followed during years 1994 to 1996. The frequency of genotype 2 was significantly increased to 41% (P=0.04) in patients treated during years 2005 to 2006. A significant reduction in HCV genotype 1b prevalence (48% to 27%, P=0.01) was also observed after this 10 years period, whereas the prevalence of HCV genotype 1a did not change over time (22% vs. 27%, NS). Transfusion was more significantly associated with infection with HCV genotype 1b than with other genotypes (52% vs. 20%, P=0.002). CONCLUSIONS: HCV subtype 1b seems to have been displaced by HCV genotype 2 in a relatively short period, without increase in the frequency of genotype 3. The low frequency of HCV genotype 3 in Venezuela might be due to the fact that intravenous drug use in Venezuela is less common than in other countries. The implementation of anti-HCV testing in blood banks since 1994 in Venezuela, might have contributed to the reduction in the frequency HCV genotype 1b infection.     

Chronic hepatitis caused by hepatitis C virus showing a discrepancy between serogroup and genotype because of intergenotypic 2b/1b recombination: A pitfall in antiviral therapy with direct‐acting antivirals

A 40‐year‐old male patient with virologic relapse after daclatasvir plus asunaprevir therapy for a serogroup 1 hepatitis C virus (HCV) infection visited our hospital for retreatment. Virologic examinations revealed that a genotype 2b HCV strain carrying both NS3‐S122N / D168A and NA5A‐R30Q / L31M / Q54H / Y93H mutations had relapsed. The patient received sofosbuvir plus ribavirin therapy, but virologic relapse occurred once again. Sequencing of the HCV genome clarified an intergenotypic recombination of 2b and 1b with an estimated crossover point between nucleotides 3114 and 3115, corresponding to the N‐terminal end of the NS3 region (DDBJ/EMBL/GenBank databases accession no. LC273304). The NS5B‐S282T mutation was not detected in the HCV strain, and resistance‐association substitutions in the NS3 and NS5A regions were similar to those at baseline. Direct sequencing of the core and NS4A regions corresponding to the targeting sites of genotyping and serogrouping, respectively, is useful to determine the combination of direct‐acting antivirals when a discrepancy is observed between the serogroup and genotype of HCV strains.     

贵州地区HCV感染者基因型分布特征

目的 探讨贵州地区丙型肝炎患者HCV基因型分布特征,为HCV感染的防控和个体化治疗提供临床依据。方法 选取2011年9月-2018年10月贵阳市公共卫生救治中心1211例HCV RNA阳性的丙型肝炎患者,采用PCR直接测序法,与GenBank中已知的HCV序列进行对比,获得HCV基因型及亚型,并分析其分布与性别、年龄、民族、地区、感染途径等因素的关系。计数资料组间比较采用χ2检验或Fisher确切概率法。结果 1211例HCV感染者共检出4种基因型和11种基因亚型,其中以1b型(26.84%)、3b型(27.17%)和6a型(24.28%)为主。不同HCV基因型在男女感染者中分布差异有统计学意义(χ2=15.428,P=0.009),其中男性以3b型为主(29.34%),女性以1b型为主(32.21%)。不同HCV基因型分布在各年龄组中差异有统计学意义(χ2=67.439,P<0.001),≤18岁组与≥60岁组以1b型为主(分别为66.67%、58.93%),而19~39岁组以3b型(28.93%)、6型(29.29%)为主,40~59岁组以1b型(29.54%)、3b型(27.33%)和6型(24.28%)为主。各种感染途径的HCV基因型分布差异有统计学意义(χ2=153.916,P<0.001),感染方式以静脉药瘾为主(57.97%),其次是性接触和有创美容(均为8.42%);经静脉药瘾、有创美容感染HCV者均以3b型为主(分别为31.48%、32.35%),性接触感染者多为HCV 6型(36.27%)。不同民族、贵州地区间HCV基因型分布差异均无统计学意义(P值均>0.05)。结论 贵州地区HCV基因型分布呈多样性,3b、1b、6a型为主要流行株,存在HCV 6型中的多种少见基因亚型,且在不同的年龄、性别、感染途径方面HCV基因型分布存在差异。     

Changing pattern of clinical epidemiology on hepatitis C virus infection in southwest china

Background

The changing pattern of hepatitis C virus (HCV) infection could have a significant impact on future medical prevention practices and therapies.

Objectives

The purpose of this study was to describe the changing pattern of HCV infection in southwest China using clinical epidemiology, and to assess the association between the genotypes distribution and certain potential risk factors.

Patients and Methods

A retrospective analysis which included 1208 subjects with chronic HCV registered at the Southwest Hospital (Chongqing, Southwest China) was performed. The information was reviewed and the data collected from clinical records and short telephone interviews when necessary. HCV genotypes were determined by nucleotide sequencing of the CE1 regions followed by phylogenic analysis with the published HCV genotype. HCV genotype distribution was analyzed according to the patients'' age, gender, risk exposure, and the initial risk exposure.

Results

Among the 1 208 patients, the HCV subtype 1b was the most prevalent (32.9%), followed by subtype 3b (18.9%), 6a (18.0%), 3a (12.8%) and 2a (10.4%), while subtypes 1a and 6k accounted for cases of HCV infection in only 9 and 3 cases respectively. Individuals older than 40 years were mainly infected with subtypes 1b and 2a, whereas younger patients were predominantly infected with genotypes 3 and 6. Subtypes 1b and 2a were observed more frequently among 44.4% and 16.0% patients respectively, with a history of invasive operations. Subtypes 3b and 6a constituted the majority of HCV infections among intravenous drug users (IDUs) (28.7% and 34.9%, respectively). A significant difference (P < 0.001) was observed between the HCV genotype distributions, according to the potential route of infection.

Conclusion

In southwest China, the most common remaining subtype is the 1b genotype, but this has declined significantly among young patients. This is followed by subtype 3b and 6a which has increased significantly, especially among young patients. The distribution of such genotypes was also variable according to gender and age. The changing pattern of HCV infection was associated with changes in the modes of HCV acquisition, which raises an alarm signal concerning the major steps that need to be taken in order to reduce such infections in southwest China.     

Enzyme-linked immunosorbent assay to detect hepatitis C virus serological groups 1 to 6

By conventional serological grouping methods, it is possible to determine hepatitis C virus (HCV) serological groups for genotypes 1a, and 1b, and genotypes 2a, and 2b, but not for other genotypes, i.e., 3a, 3b, 4a, 5a, and 6a. In this study, we attempted to serologically group HCV with the Murex HCV serotyping 1 to 6 assay (Murex Diagnostics, Kent, UK), using an enzyme-linked immunosorbent assay (ELISA) based on genotype-specific peptides from the NS4 region. The subjects of this study were 365 patients infected with HCV of genotype 1a, 1b, 2a, 2b, 3a, or 3b. The sensitivity of the assay was 100% in patients with genotype 1a, 82.7% in those with 1b, 68.5% in those with 2a, 84.2% in those with 2b, 50.0% in those with 3a, and 76.5% in those with genotype 3b. The overall sensitivity was 78.4%. The specificity of the assay was 100% in the subjects with genotype 1a, 98.8% in those with 1b, 98.4% in those with 2a, 96.9% in those with 2b, 100% in those with 3a, and 100% in those with genotype 3b. The overall specificity was 98.6%. The concordance of the assay was 100% in subjects with genotype 1a, 81.7% in those with 1b, 67.4% in those with 2a, 81.6% in those with 2b, 50.0% in those with 3a, and 76.5% in those with genotype 3b. The overall concordance was 77.5%. We believe it would be better to serotype with the Murex HCV serotyping 1 to 6 assay, if other than serological group (Gr) 1 or Gr 2 is suspected in particular ethnic groups or in subjects with an indeterminate result with the Immucheck HCV Gr assay (Kokusai, Kobe, Japan), assuming that the genotype must be other than 1a, 1b, 2a, or 2b. Received: October 22, 1998 / Accepted: February 26, 1999     

Pattern of hepatitis C virus genotypes and subtypes circulating in war-stricken Khyber Pakhtunkhwa,Pakistan: Review of published literature

Infection due to hepatitis C virus(HCV) is a major cause of fibrosis and hepatocellular carcinoma in Pakistan. In the current review, pattern of HCV genotypes and subtypes in Khyber Pakhtunkhwa province was ascertained in light of the available literature. After thorough analysis, genotype 3(58.27%) was determined to be the leading HCV genotype,followed by genotypes 2(12.39%), 1(9.54%) and 4(0.86%). The proportions of genotypes 5 and 6 were recorded as 0.09% and 0.22% respectively. Subtype wise, 3 a accounted for 48.67%, followed by subtype 2 a(10.91%), 3 b(9.43%), 1 a(5.84%), 1 b(3.66%), 2 b(1.45%) and genotype 4 with its undefined subtypes contributed a portion of0.86%. The cumulative share of subtypes 1 c, 2 c, 3 c, 5 a and 6 a was less than 1%. In11.51% cases, the subtype was untypeable while in 7.17% cases mixed subtypes were recorded. Gender wise, proportions of most HCV subtypes were marginally higher among males as compared to females. On the basis of studied groups, 3 a was pervasive among all groups except in intravenous drug users where 2 a was the major HCV subtype.Similarly, based on various geographical locations(provincial divisions), subtype 3 a revealed a ubiquitous distribution. Conclusively, HCV 3 a persists to be the principal subtype across the province of Khyber Pakhtunkhwa. The considerable number of untypeable subtypes in most studies urges for an improved genotyping system on the basis of local sequence data and practice of sequencing for determination of underlying subtype in untypeable cases. Further, studies on identification of subtypes transmission pattern are imperative for assessment of transmission origin and reinforcement of efficient control strategies. In addition, the current review emphasizes the need of attention toward HCV risk groups and ignored southern side of Khyber Pakhtunkhwa province for better holistic understanding of HCV genotype distribution pattern in the province.     

The genotype analysis of the hepatitis C virus in Heilongjiang Province,China

Introduction: Hepatitis C virus (HCV) infection is a major public health issue. HCV genotype identification is clinically important to tailor the dosage and duration of treatment, and recombination in intra-patient populations of HCV may lead to the generation of escape mutants, as previously observed for other RNA viruses. Up to now, there is no study assessing HCV genotypes and subtypes in Heilongjiang Province, China.Methods: To determine genotype and phylogenetic analysis of HCV in Heilongjiang Province is crucial. In this study, we amplified 3 genome regions (5’UTR, E1, and NS5B) of 30 HCV patients in Heilongjiang Province, amplified products were analyzed by bioinformatics.Results: We found that 23 specimens had concordant subtypes in the 3 gene regions (2a and 1b), 7 HCV patients were considered the recombinants, the recombination pattern of the 7 HCV patients in the 5’UTR, E1, and NS5B region as followed: 1b/2a/1b, 2a/2a/1b, 1b/2a/2a, 1b/2a/1b, 1b/2a/1b, 1b/2a/1b, 2a/2a/1b.Conclusions: The findings in the present study showed that a higher recombination rate (23%) than other researches, and the recombination of 2a/1b in the 5’UTR, E1, and NS5B region was only found in the present study up to now.     

Distribution of hepatitis C virus genotypes in patients with chronic hepatitis C infection in Western Turkey.

OBJECTIVE: The primary aim of this study was to determine the recent distribution of various genotypes of hepatitis C virus (HCV) in patients with chronic HCV infection in Western Turkey. Additional objectives were to determine whether there are any associations of genotype with gender and age, and to determine the nucleotide similarities and risk factors of non-1 HCV genotypes. METHODS: Serum samples from 345 patients (176 male, 169 female; mean age 53.3+/-12.7 years, range 10-81 years) with chronic HCV infection were analyzed in this study. Viral genotypes were determined by a restriction fragment length polymorphism (RFLP)-based in-house assay. To confirm genotypes for the samples with band patterns other than genotype 1, the 5' UTR was amplified and sequenced. RESULTS: Genotype 1 was observed in 335 of the 345 patients (97.1%). Of these, 34 patients showed infection with subtype 1a (9.9%) and 301 with subtype 1b (87.2%). Genotypes 2, 3, and 4 were determined in 0.9%, 1.4%, and 0.6% of the patients, respectively. Patients infected with type 1 were significantly older than patients infected with non-1 genotypes; however no significant differences were recorded in gender distribution. CONCLUSIONS: Genotypes other than genotype 1 are quite rare; these are possibly acquired in other countries. Turkish patients with chronic hepatitis C still represent a rather homogenous group with genotypic diversity encountered rarely.     

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

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

中国兰州地区丙型肝炎病毒感染的基因型分布特征

目的了解中国兰州地区丙型肝炎病毒（HCV）感染基因型分布特点。方法筛选41例来自兰州的HCVRNA阳性患者血清样品,扩增HCV5′非编码区（5’NCR）,得到257bp的聚合酶链反应（PCR）产物,并对这些产物进行测序。然后将所得序列与GenBank参考序列比对,并作同源性分析和进化分析。结果 41例样品中共检出1b型感染25例（61.0%）,1c型感染8例（19.5%）,2a型4例（9.8%）,1a型3例（7.3%）,3b型感染1例（2.4%）。结论兰州地区的基因型分布以1b型为主,并首次在中国检出1c型感染,且感染率仅低于1b型;此外还检出2a、1a和3b;未检出4、5和6型等基因型。     

Genotype distribution amongst hepatitis C patients in The Netherlands

BACKGROUND: The prevalence of the genotypes of the hepatitis C virus (HCV) differs according to geographical location. In the United States and in European countries, the majority of patients are infected with genotype 1, 2 or 3. There is a lack of data on the distribution of HCV genotypes in The Netherlands. METHODS: The current survey determined the distribution of HCV genotypes amongst recently genotyped patients seen by physicians treating hepatitis C in The Netherlands. RESULTS: Almost half of the 351 patients (49.3%) were infected with genotype 1. Genotype 3 was the second most dominant genotype with a prevalence of 29.3%. Genotypes 2 and 4 were found in 9.7 and 10.5% of the patients, respectively. For 61.5% of the patients (n=216), the subtype was available. For genotype 1 the prevalence of subtype 1a and 1b was very similar, while for genotype 3 a large majority of patients were infected with subtype 3a. CONCLUSION: This survey gives the first estimation of the distribution of HCV genotypes amongst unselected HCV patients in The Netherlands.     

Effect of mutation in the hepatitis C virus nonstructural 5B region on HCV replication

Background We have reported that the presence of a mutation at the hepatitis C virus (HCV) nonstructural protein 5B (NS5B), defined as a change in amino acids at sites specific for a different reported genotype, was related to complete response (CR) to interferon (IFN) therapy in patients with chronic hepatitis C (CHC) with genotype 1b. The present study assessed the impact of the NS5B mutation on the replication of HCV in these patients.Methods Genotype-specific mutations of HCV NS5B were determined by direct sequencing. We measured HCV-RNA titers in serum by real-time detected polymerase chain reaction (PCR), and serum HCV core protein levels (as a marker of HCV-RNA replication) were measured using an enzyme immunoassay in patients with CHC genotype 1b. RNA-dependent RNA polymerase (RdRp) activity was measured by Behrens method in liver cirrhosis patients infected with HCV (n = 13) and in those infected with hepatitis B virus (HBV; n = 2).Results The titers of HCV-RNA (n = 44) and the levels of HCV core protein (n = 41) were significantly lower in patients with the HCV genotype 1b mutant compared with wild-type HCV (P < 0.05). RdRp activity in liver tissue did not show any correlation with the HCV NS5B mutation.Conclusions HCV NS5B genotype-specific mutations in HCV genotype 1b may influence HCV replication.