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

Unveiling the dynamics of hepatitis C virus transmission among injection drug users and men who have sex with men: A comprehensive study in Japan

AIM

In Japan, despite low nationwide hepatitis C (HCV) incidence, new infections among people who inject drugs (PWID) and men who have sex with men (MSM) hinder HCV elimination. We explored HCV transmission dynamics and screened HCV recombination within these populations.

METHODS

This cross-sectional study recruited HCV-infected patients from Osaka National Hospital, Osaka, Japan, from January 2010 to September 2023. Data from questionnaires and medical records were analyzed. Serum samples collected before anti-HCV treatment underwent HCV RNA extraction, and sequencing of full core (576 bp) and NS5B (267 bp) regions using the Sanger method. Genotype distribution was determined by phylogenetic analysis, and recombinant screening was conducted.

RESULTS

A total of 115 patients were categorized into non-MSM PWID (31), MSM PWID (15), MSM non-PWID (25), and non-MSM non-PWID (44). Positive amplification rates were 99.1% (114/115) for the full-core region, and 96.5% (111/115) for NS5B. No intergenotypic recombination was detected. The predominant genotype in non-MSM PWID was 2a (58%), whereas genotype 1b was most common in MSM PWID, MSM non-PWID, and non-MSM non-PWID groups (79%, 64%, and 68%, respectively). Nucleotide sequence similarity of 94.75%-100% was found in HCV strains from MSM PWID and MSM non-PWID in both full-core and NS5B regions, whereas strains from non-MSM PWID and non-MSM non-PWID were distinct.

CONCLUSION

The findings suggest that the transmission route in PWID is determined by MSM status, whereas MSM groups showed the same transmission route regardless of PWID. HCV control measures should be focused not only on PWID, but also on MSM to achieve HCV elimination in Japan.

Real-world performance of the NeuMoDx™ HCV Quant Test for quantification of hepatitis C virus (HCV)-RNA

Quantification of hepatitis C virus (HCV)-RNA in serum or plasma samples is an essential parameter in HCV diagnostics. Here, the NeuMoDx™Molecular System (Qiagen) was tested for the most common HCV genotypes and compared to the cobas c6800 system (Roche). HCV-RNA from 131 plasma/serum samples from chronically infected patients was determined in parallel on the NeuMoDx and c6800 systems. Linearity was analysed using the four most common HCV genotypes (1-4) in our cohort. The coefficient of variation (CV) within (intra-assay) and between (inter-assay) runs was calculated based on HCV-RNA concentration. Quantitative HCV-RNA results were highly correlated on both test systems (R2 = 0.7947; y = 0.94 x + 0.37). On average, the NeuMoDx and c6800 HCV RNA levels showed a mean difference of only 0.05 log10 IU/mL but with a broad distribution (±1.2 2 x SD). The NeuMoDx demonstrated very good linearity across all HCV genotypes tested at concentrations between 1.7 and 6.2 log10 IU/mL (R2 range: 0.9257-0.9991) with the highest mean coefficient of determination for genotype 1 (R2 = 0.9909). The mean intra- and inter-assay CV for both serum and plasma samples was <5 %. The NeuMoDx HCV-RNA Assay demonstrates high subtype-independent comparability, linearity, and reproducibility for the quantification of HCV-RNA in serum and plasma samples from chronically infected patients.

HCV 6a was expanding and became the predominant subtype among blood donors between 2004 and 2019 in Guangdong, China

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Currently, HCV 6a has replaced 1b as the most prevalent subtype in blood donors in Guangdong.

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HCV 6a was the predominant subtype in males and older donors, while 1b predominated in females and younger donors.

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HCV 6a may expand from Guangdong to other districts of China, and is worthy of attention.

Real-world utility of HCV core antigen as an alternative to HCV RNA testing: Implications for viral load and genotype

Following positive serology, the gold standard confirmatory test of hepatitis C virus (HCV) infection is detection of HCV RNA by PCR. We assessed the utility of HCV core antigen testing to identify active infection among those positive for anti-HCV antibodies, when introduced to routine testing. We identified serum samples that were tested at a single laboratory in Scotland from June 2011to December 2017. Serum samples testing positive for HCV antibodies (HCV Ab positive) followed by reflex HCV core antigen (Ag) testing during the study period were identified. Those patients for whom a PCR test was requested on the baseline sample were also identified. For this group, the sensitivity and specificity of HCV Ag as a diagnostic tool were assessed using HCV PCR as gold standard. In our cohort of 744 patients, we demonstrated a sensitivity of 82.1% (95% CI 77.1%-86.2%) and a specificity of 99.8% (95% CI 98.6%-100%). Genotype 3 was associated with increased odds of a false-negative result (OR = 3.59, 95% CI: 1.32-9.71), and reduced odds of a false negative were associated with older age (odds ratio (OR)=0.92, 95% CI: 0.88-0.97 per year) and viral load (OR = 0.10, 95% CI: 0.05-0.21 per log₁₀ IU/ml). While the implementation of HCV core antigen testing for diagnosis could lead to significant cost savings in national screening programmes, our data suggest that a significant proportion of HCV-infected individuals may be missed. These findings have implications for HCV diagnosis and determination of viral clearance after treatment, particularly in low- and middle-income regions, where genotype 3 is prevalent.

Association of HCV genotype with viral load among Iranian blood donors: a penalized logistic regression

Background: Hepatitis C virus (HCV) is a blood born virus and the leading cause of advanced hepatitis disease. HCV genotype 3a is predominant among Iranian blood donors. The aim of this study was to evaluate the relationship between HCV genotype and HCV viral load. Methods: In this analytical cross-sectional study 106 anti-HCV positive and HCV RNA positive blood donors referred to Iranian blood centers across the county were entered. HCV viral loads were determined by an in-house one step Taq Man Real-Time RT-PCR assay. Penalized logistic regression was performed for data analysis. STATA software version 13 was used for statistical analysis. Results: The mean age was 37.94 ± 9.04 years ranged from 19 to 58 years. Male gender included 104 (98.1%) of subjects. 31, 10 and 65 subjects were infected with genotypes1a, 1b, and 3a, respectively. The mean viral load was 1.44 × 106 ± 4.5× 105 IU/ml. HCV viral load was not significantly different among subjects infected with HCV genotypes 1, 1.49 × 10 6 ± 4.57 × 10 6 IU/ml compare to genotype 3, 1.40 × 10 6 ± 5.58 4.58 × 106 IU/ml (p=0.93). Conclusion: Although not significant, the frequency of subjects with high viral load (> 800,000 IU/ml) was higher in subjects infected with genotype 3 than those of genotype 1. No associations were found between demographic characteristics and HCV genotype. Although the study was unable to find any association between HCV genotype and HCV viral load/ HCV viral load group, it highlighted the role of high viral load in the high circulation of HCV genotype 3a among Iranian blood donors.

HCV genotype 6 prevalence, spontaneous clearance and diversity among elderly members of the Li ethnic minority in Baisha County, China

The epidemiology of hepatitis C virus varies widely across geographical regions and ethnic groups. Our previous study showed that 6 strains isolated from Baisha County, Hainan Island, China, were all new genotype 6 (gt6) subtypes which differed significantly from subtypes of other regions. In the current study, we conducted a comprehensive epidemiological survey of HCV in the Li ethnic group, native to Baisha County. Anti-HCV antibodies were detected by 2 independent ELISAs in all participants, and positive results confirmed by the recombinant immunoblot assay (RIBA) and HCV RNA viral loads were measured. Univariate chi-square test and multivariable logistic regression analyses were used to determine the risk factors for HCV infection and spontaneous clearance rates. Indeterminate RIBA results were excluded or included in analyses; consequently, findings were expressed as a range. Direct sequencing of partial regions within NS5B and E1 was employed for genotyping. Among 1682 participants, 117 to 153 were anti-HCV positive (7.0%-9.1%), with 42.7%-52.6% confirmed to have cleared infection. Anti-HCV positivity was associated with older age (≥60 years) (OR = 0.02, 95% CI 0.01-0.05, P < 0.01) and surgery (OR = 2.75, 95% CI 1.36-5.57, P < 0.01), with no significant difference found between the HCV infection group and the HCV spontaneous clearance group. The gt6 subtype distribution characteristics of Baisha County were unique, complex and diverse. The sequences did not cluster with known gt6 subtypes but formed 4 Baisha community-specific groups. HCV infection in members of the Li minority ethnic group is characterized by high prevalence rates in the elderly, high spontaneous clearance rates and broad gt6 diversity.

High CD8 T cell percentage and HCV replication control are common features in HIV-1 controllers and HTLV-2-co-infected patients with a history of injection drug use

HTLV-2/HIV-1-coinfected patients and HIV-infected patients with natural HIV-1 control show an immune capacity that allows some control of viral infections. These two groups of patients have showed an immune capacity that allows them to have some control over viral infections, very strong control of HIV-1 replication in the case of HIV-1 controllers. The purpose of this retrospective cross-sectional study was to compare viral and immunologic parameters between three cohorts of Caucasian adult HIV-1-infected patients, including HIV-1 controllers (29 patients), HTLV-2/HIV-1 chronic progressors (56 patients), and HIV-1 chronic progressors (101 patients), followed in two different tertiary University Hospitals in Spain. Demographic parameters, nadir CD4 T cell count, CD4 and CD8 T cell counts and percentage, anti-HCV antibodies, HCV RNA load, HCV genotype, HIV-1 RNA loads, and anti-HTLV-2 antibodies were analyzed. HIV-1 controllers and HTLV-2/HIV-1 chronic progressors were younger and with shorter time since HIV-1 diagnosis compared to HIV-1 chronic progressors. HIV-1 controllers and HTLV-2/HIV-1 chronic progressors had significantly higher CD8 T cell percentage (p = 0.002 and p = 0.016, respectively) and lower levels of HCV RNA loads (0.015 and 0.007, respectively) compared to that of HIV-1 chronic progressors. Multivariate analyses showed that gender and HTLV-2 infection were independently associated to HCV RNA load, while only HTLV-2 infection was independently associated to CD8 T cell percentage. The implication of HTLV-2 infection in the control of HIV-1 and HCV infections is worth being further analyze.

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.

Hepatitis C Virus in mainland China with an emphasis on genotype and subtype distribution

Due to the low fidelity of the RNA-dependent RNA polymerase, Hepatitis C virus (HCV) mutates quite frequently. There are seven genetically divergent genotypes (GTs) distributed in the world, each of which contains several closely related subtypes. The peer-reviewed literatures reporting the prevalence rate of HCV GTs in Chinese hospitalized patients were identified by systematic searching of three electronic databases, and the prevalence rates were pooled through 137 qualified studies. The significant difference between HCV GT and HCV viral load and severity of hepatitis were analyzed under Chi-squared or Fisher's exact test. Data from epidemiological studies on hospitalized patients demonstrated that HCV GTs 1-6 have been found in China, of which 1b (62.78%(95% CI: 59.54-66.02%)) and 2a (17.39% (95% CI: 15.67-19.11%)) are the two predominant subtypes. HCV GTs and subtypes exhibits significant regional divergence. In North, Northwest, Northeast, East (except Jiangxi province) and Central China (except Hunan province), HCV-1b, 2a remain the two predominant subtypes; South China shows the most abundant genetic diversity that 14 subtypes were found, and HCV-3 in the Southwest China remains higher prevalent subtype than the other regions. In addition, co-infection in Liaoning province of Northeast China is the most diverse with 10 co-infection types, and Tibet has the highest rate of co-infection. The associations between HCV GTs and patients group, severity of illness and antiviral treatment efficacy were also discussed in this review.

Assessment of HCV genotypes in Yunnan Province of Southwest China

Recently, we reported that the frequency of hepatitis C virus (HCV) genotypes and subtypes has rapidly changed among intravenous drug users (IDUs) in Yunnan Province over the last 5 years; this is especially true for subtype 6a which has increased in frequency from 5 to 15%. Here, we assessed 120 HCV-positive plasma samples from the general population (GP). HCV NS5B fragments were amplified and sequenced by PCR. We identified four HCV genotypes (1, 2, 3 and 6) and seven HCV subtypes (1b, 2a, 3a, 3b, 6a, 6n, and 6k) in this population. Genotype 3 was predominant, with a distribution frequency of 0.484, followed by genotype 1 (0.283), genotype 6 (0.133) and genotype 2 (0.100). HCV subtypes 3b (frequency 0.292) and 1b (frequency 0.283) were the most common subtypes. A comparison of the current data with previous results reported for IDUs showed that the distribution frequencies of genotypes 1, 2 and 6 were significantly different between patients in the GP and IDUs (P < 0.05). Among the HCV subtypes, the distribution frequencies of 1b, 2a, 6a, and 6n were significantly different between patients in the GP and IDU groups (P < 0.05). Moreover, Phylogenetic analyses showed that HCV subtype 6a strains isolated from IDUs and the GP were intermixed and not separately clustered. HCV subtype 6a was predominant not only among IDUs but also among those in the GP in the Guangdong Province and Vietnam. However, HCV subtype 6a was predominant only among IDUs and not among those in the GP in the Yunnan and Guangxi Provinces. Our results indicate that the HCV subtype 6a could rapidly spread across China.

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.

Association of genotypes with viral load and biochemical markers in HCV-infected Sindhi patients

The presented study had two objectives. The first was to examine distributions of Hepatitis C Virus (HCV) genotypes in Sindh, Pakistan, where HCV is prevalent. The other was to explore clinically relevant relationships between the genotypes, viral load (measured by real-time polymerase chain reaction assays) and biochemical markers. For this, 1471 HCV-infected patients in six cities in Sindh were recruited and sampled. HCV genotype distributions varied among the cities, but genotype 3a was most prevalent, followed by 3b, 1a and 1b (detected in 51.5, 22.7. 9.25 and 3.2% of the cases, respectively). No type-specific sequences were detected in serum samples from 189 (12.8%) of the 1471 patients. Frequencies of low (<200,000IU/mL serum), intermediate (200,000-600,000IU/mL serum) and high (>600,000IU/mL serum) viral loads were respectively 45.4, 16.5 and 38.1% for patients infected with genotype 3, and 16.9, 36.9 and 46.2%, respectively, for patients with other genotypes. Infection with genotype 1a was associated with significantly higher (p<0.005) alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase titers than infection with genotype 3a. The results will help in the formulation of treatment strategies.

Factors associated with hepatitis C virus RNA levels in early chronic infection: the InC3 study

Improved understanding of natural history of hepatitis C virus (HCV) RNA levels in chronic infection provides enhanced insights into immunopathogenesis of HCV and has implications for the clinical management of chronic HCV infection. This study assessed factors associated with HCV RNA levels during early chronic infection in a population with well-defined early chronic HCV infection. Data were from an international collaboration of nine prospective cohorts studying acute HCV infection (InC(3) study). Individuals with persistent HCV and detectable HCV RNA during early chronic infection (one year [±4 months] postinfection) were included. Distribution of HCV RNA levels during early chronic infection was compared by selected host and virological factors. A total of 308 individuals were included. Median HCV RNA levels were significantly higher among males (vs females; 5.15 vs 4.74 log IU/mL; P < 0.01) and among individuals with HIV co-infection (vs no HIV; 5.89 vs 4.86; P = 0.02). In adjusted logistic regression, male sex (vs female, adjusted odds ratio [AOR]: 1.93; 95%CI: 1.01, 3.69), interferon lambda 4 (IFNL4) rs12979860 CC genotype (vs TT/CT; AOR: 2.48; 95%CI: 1.42, 4.35), HIV co-infection (vs no HIV; AOR: 3.27; 95%CI: 1.35, 7.93) and HCV genotype G2 (vs G3; AOR: 5.40; 95%CI: 1.63, 17.84) were independently associated with high HCV RNA levels (>5.6 log IU/mL = 400 000 IU/mL). In conclusion, this study demonstrated that IFNL4 rs12979860 CC genotype, male sex, HIV co-infection and HCV genotype G2 are associated with high HCV RNA levels in early chronic infection. These factors exert their role as early as one year following infection.

HLA-B alleles B*15:01 and B*15:02: opposite association with hepatitis C virus infection in Chinese voluntary blood donors

BACKGROUND

Although human leukocyte antigens (HLA) have been shown in association with the outcomes of hepatitis C virus (HCV) infection among different ethnic groups, such studies remain absent in China, where the HCV prevalence is higher than the global average.

METHODS

In this study, 426 HCV-infected and 709 uninfected blood donors were analyzed, among whom the HLA alleles were sequenced using a high-resolution genotyping method.

RESULTS

At the 2-digit level, none of the alleles showed a statistical difference between the HCV-infected and uninfected groups. However, at the 4-digit level, the HLA-B alleles B*15:01 and B*15:02 showed an opposite association with HCV infection, i.e. B*15:01 was significantly higher in the HCV-infected group (odds ratio, OR = 1.561, p = 0.010), while B*15:02 was significantly higher in the uninfected group (OR = 0.778, p = 0.016). We also identified a higher frequency of B*13:02 in the HCV-infected group (OR = 1.515, p = 0.009) and a higher frequency of B*07:05 in the uninfected group (OR = 0.299, p = 0.001).

CONCLUSIONS

The frequencies of four HLA alleles, B*07:05, B*13:02, B*15:01, and B*15:02, were found to be significantly different between the HCV-infected and uninfected blood donors in China, revealing an inverse relation of B*15:01 and B*15:02 with HCV infection. This finding suggests that the ethnic genetic variations of HLA may greatly affect the host immune responses against HCV.

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.

Increased prevalence of hepatitis C virus subtype 6a in China: a comparison between 2004-2007 and 2008-2011

Different hepatitis C virus (HCV) genotypes exhibit differences in disease pathogenesis and progression, as well as disease outcomes and response to therapy. Tracking the change of HCV genotypes in various epidemiological settings is critical for both disease surveillance and the development of improved antiviral treatment. Here, we tracked the changes in the prevalence of the HCV genotypes in China between 2004-2007 and 2008-2011. HCV-RNA-positive sera were collected from volunteer blood donors during the period 2008-2011. The genotypes were determined by phylogenic analysis using the NS5B and E1 sequences. Geographical and demographic distribution patterns related to the HCV genotypes obtained in 2008-2011 were compared with our previous study, which recorded data in the period 2004-2007. Pearson chi-square test and t-test were used to statistically analyze the results. In 2008-2011, HCV subtypes 1b and 6a were detected in 43.8 % (184/420) and 34.3 % (144/420), respectively. The male/female ratio was found to be higher for HCV genotype 6 than for genotypes 1 and 2. When compared with the period of 2004-2007, although no significant difference was found in gender or age for genotypes 1, 2, 3 and 6, the subtype 6a frequency was significantly increased from 11 % to 26.5 % in the blood donors from outside of Guangdong Province in 2008-2011. A pattern of increase in HCV subtype 6a was found in blood donors outside of Guangdong Province, indicating that HCV subtype 6a has rapidly spread from Guangdong to other regions of China over the past 10 years.

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.

Transmission dynamics of hepatitis C virus among intra venous drug users in the border state of Manipur, India

Intra venous drug users (IVDUs) are at high risk for hepatitis C virus (HCV) infection owing to their high rate of drug abuses. The north-eastern part of India has a high prevalence of IVDUs with Manipur being the worst hit state. The aim of the study was to document the molecular epidemiology, the patterns of HCV transmission, genomic variation and recombination events within HCV genome among IVDUs of Manipur, India. 91 anti-HCV sero-reactive blood samples were collected from IVDUs in Manipur. The samples were processed for RNA extraction, nested RT-PCR, sequencing and quantitative viral RNA estimation. Phylogeographic analysis of the sequenced core and NS5B regions of HCV genome was performed to determine the probable transmission route and recombinant HCV strains. 83 out of 91 anti-HCV seropositive samples were RNA positive (91.20%) based on 5'UTR of HCV genome by nested RT-PCR. Of the RNA positive samples, 73 paired partial core and NS5B gene were sequenced. Three major genotype and eight subtypes were detected while no recombinant strains were found. Individuals with genotype 1 had the mean viral load (5.94 ± 0.705 log10IU/ml) followed by genotype 3 (4.91 ± 0.49 log10IU/ml) and 6 (3.96 ± 0.32 log10IU/ml). The viral load was statistically significant among the male individuals at 4.822 ± 1.36 log10IU/ml compared to 4.767 ± 0.49 log10IU/ml for females (t=3.249, p<0.005). The phylogeographic results indicated 3b, 6h originated from Vietnam, 1a had Indian origin, 3a, 6k originated from southern China while 1b originated from Myanmar, respectively. The incidence of eight different subtypes in Manipur reflects the transmission of these strains from the "Golden Triangle" drug trafficking regions. Sequence analysis confirmed the transmission routes of HCV, which is linked to China and Vietnam for the newly emergent genotype 6 in north-eastern India.

HCV genotypes, characterization of mutations conferring drug resistance to protease inhibitors, and risk factors among blood donors in São Paulo, Brazil

Background

Hepatitis C virus (HCV) infection is a global health problem estimated to affect almost 200 million people worldwide. The aim of this study is to analyze the subtypes and existence of variants resistant to protease inhibitors and their association with potential HCV risk factors among blood donors in Brazil.

Methods

Repeat anti-HCV reactive blood donors are systematically asked to return for retest, notification, and counseling in which they are interviewed for risk factors for transfusion-transmitted diseases. We analyzed 202 donors who returned for counseling from 2007 to 2010 and presented enzyme immunoassay- and immunoblot-reactive results. The HCV genotypes and resistance mutation analyses were determined by the direct sequencing of the NS5b and NS3 regions, respectively. The HCV viral load was determined using an in-house real-time PCR assay targeting the 5′-NCR.

Results

HCV subtypes 1b, 1a, and 3a were found in 45.5%, 32.0%, and 18.0% of the donors, respectively. The mean viral load of genotype 1 was significantly higher than that of the genotype 3 isolates. Subtype 1a was more frequent among young donors and 3a was more frequent among older donors. Protease inhibitor-resistant variants were detected in 12.8% of the sequenced samples belonging to genotype 1, and a higher frequency was observed among subtype 1a (20%) in comparison to 1b (8%). There was no difference in the prevalence of HCV risk factors among the genotypes or drug-resistant variants.

Conclusions

We found a predominance of subtype 1b, with an increase in the frequency of subtype 1a, in young subjects. Mutations conferring resistance to NS3 inhibitors were frequent in treatment-naïve blood donors, particularly those infected with subtype 1a. These variants were detected in the major viral population of HCV quasispecies, have replicative capacities comparable to nonresistant strains, and could be important for predicting the response to antiviral triple therapy.

Analysis of hepatitis C virus subgenotypes in patients in Heilongjiang province

AIM: To analyze the distribution of different hepatitis C virus (HCV) subgenotypes in Heilongjiang province, China.

METHODS: Serum samples from 1 313 patients with HCV infection, including 627 (47.75%) males and 686 (52.25%) females, were subgenotyped using multiplex nested PCR assay. The associations of HCV subgenotypes with gender, age, viral load, and ALT level were analyzed.

RESULTS: Of 1 313 patients, 927 (70.60%) were successfully subgenotyped. Among typable subgenotypes, 1b⁺/2a^- was found in 388 (41.86%) cases, 2a⁺/1b^- in 318 (34.30%) cases, 1b+2a in 197 (21.25%) cases, and 1a+/2b in 24 (2.59%) cases. The percentage of patients with 2a⁺/1b^- subgenotype was significantly higher in females (37.50%) and patients with HCVRNA of (1.000-9.999) × 10⁴ (54.55%), ALT level >200 (60.87%) or ≤ 40 (41.02%) (all P < 0.05). The percentage of patients with 1b⁺/2a^- subgenotype was significantly lower in patients with HCVRNA of (1.000-9.999) × 10⁴ (24.24%) or ALT level >200 (13.04%) (both P < 0.05).

CONCLUSION: Genotypes 1b and 2a are the most prevalent genotypes in Heilongjiang province. The distribution of different HCV subgenotypes is associated with gender, viral load, and ALT level.