Molecular epidemiology of hepatitis B and C virus infections in Asia

Molecular epidemiology of hepatitis B virus (HBV) in Ethiopia: A review article

Hepatitis B virus (HBV) belongs to the family Hepadnaviridae and is the smallest human DNA virus, with a genome that is only 3200 nucleotides long. The absence of proofreading function in HBV reverse transcriptase provides a wide range of genetic variants for targeted outgrowth at different stages of infection. A number of sub genotypes and ten HBV genotypes (A through J) have been identified through analyses of the divergence of HBV genomic sequences. Numerous clinical outcomes, including the emergence of chronicity, the course of the disease, the effectiveness of treatment, and the response to vaccination, have been related to differences in genotype between HBV isolates. There are just seven studies that have been done in Ethiopia that examine the molecular epidemiology of HBV. Moreover, these studies haven't been compiled and reviewed yet. In this review, we looked at the genetic diversity and molecular epidemiology of HBV, the relationship between HBV genotypes and clinical outcomes, the immunopathogenesis of HBV, and finally the molecular epidemiology of HBV in Ethiopia. PubMed, Embase, and Google Scholar search engines were used to find relevant articles for the review. By using HBV genotyping, clinicians can better tailor vaccination decisions and antiviral therapy for patients with chronic hepatitis B who are more likely to experience the disease's progression.

Hepatitis B virus genotypes associated with pregnant women in Northern Thailand

BACKGROUND

Mother-to-child transmission of hepatitis B virus (HBV) is the major route of transmission causing persistent infection. The prevalence of HBV infection and HBV genotypes found in different geographical areas varies from country to country. Therefore, this study was conducted to identify the HBV genotypes in HBV-infected pregnant women in Northern Thailand.

METHODS

Stored blood samples that were collected from 145 HBsAg-positive pregnant women who gave birth at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand from 2017 to 2020 were analyzed. The partial nucleotide sequence of the S gene of HBV was amplified by nested PCR and sequenced. All sequences were analyzed phylogenetically together with the reference strains to define the HBV genotypes.

RESULTS

A total of 31 blood samples from 145 HBsAg-positive pregnant women were positive for HBV by nested PCR. The detected HBV strains were identified as presumptive subgenotypes C1 (77.4%; 24/31), B9 (9.7%; 3/31), C2 (3.2%; 1/31), B2 (3.2%; 1/31), B4 (3.2%; 1/31), and presumptive B4/C2 recombinant subgenotype (3.2%; 1/31).

CONCLUSIONS

The findings revealed that presumptive subgenotype C1 was the most common subgenotype circulating in pregnant women in Northern Thailand and accounted for 77.4% of cases, followed by presumptive subgenotypes B9, C2, B2, and B4. Furthermore, this study reported, for the first time in Thailand, the HBV genotypes and presumptive subgenotypes, particularly subgenotype B9 circulating in pregnant women.

Genetic diversity, haplotype analysis, and prevalence of Hepatitis B virus MHR mutations among isolates from Kenyan blood donors

BACKGROUND

The rapid spread of HBV has resulted in the emergence of new variants. These viral genotypes and variants, in addition to carcinogenic risk, can be key predictors of therapy response and outcomes. As a result, a better knowledge of these emerging HBV traits will aid in the development of a treatment for HBV infection. However, many Sub-Saharan African nations, including Kenya, have insufficient molecular data on HBV strains circulating locally. This study conducted a population-genetics analysis to evaluate the genetic diversity of HBV among Kenyan blood donors. In addition, within the same cohort, the incidence and features of immune-associated escape mutations and stop-codons in Hepatitis B surface antigen (HBsAg) were determined.

METHODS

In September 2015 to October 2016, 194 serum samples were obtained from HBsAg-positive blood donors residing in eleven different Kenyan counties: Kisumu, Machakos, Uasin Gishu, Nairobi, Nakuru, Embu, Garissa, Kisii, Mombasa, Nyeri, and Turkana. For the HBV surface (S) gene, HBV DNA was isolated, amplified, and sequenced. The sequences obtained were utilized to investigate the genetic and haplotype diversity within the S genes.

RESULTS

Among the blood donors, 74.74% were male, and the overall mean age was 25.36 years. HBV genotype A1 (88.14%) was the most common, followed by genotype D (10.82%), genotype C (0.52%), and HBV genotype E (0.52%). The phylogenetic analysis revealed twelve major clades, with cluster III comprising solely of 68 blood donor isolates (68/194-35.05%). A high haplotype diversity (Hd = 0.94) and low nucleotide diversity (π = 0.02) were observed. Kisumu county had high number of haplotypes (22), but low haplotype (gene) diversity (Hd = 0.90). Generally, a total of 90 haplotypes with some consisting of more than one sequence were observed. The gene exhibited negative values for Tajima's D (-2.04, p<0.05) and Fu's Fs (-88.84). Several mutations were found in 139 isolates, either within or outside the Major Hydrophilic Area (MHR). There were 29 mutations found, with 37.9% of them situated inside the "a" determinant. The most common mutations in this research were T143M and K122R. Escape mutations linked to diagnostic failure, vaccination and immunoglobulin treatment evasion were also discovered. Also, one stop-codon, W163STP, inside the MHR, was found in one sample from genotype A.

CONCLUSION

In Kenya, HBV/A1 is still the most common genotype. Despite limited genetic and nucleotide diversity, haplotype network analysis revealed haplotype variance among HBV genotypes from Kenyan blood donors. The virological properties of immune escape, which may be the source of viral replication endurance, were discovered in the viral strains studied and included immune-escape mutations and stop-codon. The discovery of HBsAg mutations in MHR in all isolates highlighted the need of monitoring MHR mutations in Kenya.

Worldwide Incidence and Mortality of Biliary Tract Cancer

Background and Aims

Biliary tract cancer (BTC) consists of a group of hepatic and perihepatic tumors that are in close proximity but are anatomically different, including gallbladder cancer (GBC), cholangiocarcinoma (extrahepatic and intrahepatic [ICC]), and ampulla of Vater cancer (AVC). Most epidemiologic research has focused on 1 or more anatomic subtypes, or does not differentiate BTC from hepatocellular carcinoma or other primary liver cancers. Here, we provide a descriptive update on global incidence and mortality rates for BTC, overall and by anatomic subtypes.

Methods

Age-standardized rates (per 100,000 person-years) were derived from the International Agency for Research on Cancer, Cancer Incidence in Five Continents, Volume XI (2008-2012; 22 countries), and the World Health Organization Mortality Database (2006-2016; 38 countries).

Results

BTC incidence varied by country, with the highest in Chile (14.35) and the lowest in Vietnam (1.25). Mortality rates for BTC were highest for the Republic of Korea (11.64) and lowest for the Republic of Moldova (1.65). BTC mortality rates increased over time in 24 of 34 countries. Patients aged ≥75 years had 5-10 times higher mortality rates than the overall BTC rate in all countries. In most countries, incidence rates were highest for GBC, and mortality rates highest for ICC, while both were lowest for AVC. Females had and died from GBC more frequently than males. For ICC, extrahepatic cholangiocarcinoma, and AVC, males trended toward higher incidence and mortality rates.

Conclusion

The increasing incidence and mortality trends reported here indicate a need for improved prevention and treatment for all BTC subtypes.

Adolescents with chronic hepatitis C might be good candidates for direct-acting antiviral therapy

Three Japanese adolescents with chronic hepatitis C were treated by direct-acting antivirals (DAAs). No adverse events or laboratory abnormalities were observed during and after DAA therapy, and a sustained virological response was achieved in all cases. The emotional functioning of the patients and their mothers were improved after DAA therapy.

Genetic diversity of hepatitis B virus in Yunnan, China: identification of novel subgenotype C17, an intergenotypic B/I recombinant, and B/C recombinants

Yunnan is considered to be a geographical hotspot for the introduction, mutation and recombination of several viruses in China. However, there are limited data regarding the genotypic profiles of hepatitis B virus (HBV) in this region. In this study, we characterized 206 HBV strains isolated from chronic hepatitis B patients in Yunnan, China. Initial genotyping based on 1.5 kb sequences revealed that genotype C was the most prevalent at 52.4 % (108/206), followed by genotype B at 30.6 % (63/206) and unclassified genotypes at 17.0 % (35/206). To characterize the 35 unclassified strains, 32 complete HBV genomes were amplified and analysed; 17 isolates were classified within a known subgenotype, 8 were classified as B/C recombinants, 1 was classified as a B/I recombinant and 6 constituted a potentially novel C subgenotype that we designated as C17, based on the characteristics of a monophyletic cluster, >4 % genetic distances, no significant evidence of recombination and no epidemiological link among individuals. Thus, multiple subgenotypes - namely B1, B2, B4, C1, C2, C3, C4, C8 and C17 - and two distinct intergenotypic recombinants exist in Yunnan, China, highlighting the complex and diverse distribution pattern of HBV genotypic profiles.

Analysis of TRIM21 Genetic Variants on the Clinicopathologic Characteristics of Patients with Hepatocellular Carcinoma

Tripartite motif 21 (TRIM21) plays an important role in hepatocellular carcinoma (HCC). However, the gene polymorphisms of TRIM21 in HCC is not as well known. In this study, two single nucleotide polymorphisms (SNPs) in the TRIM21 gene, rs4144331, and re915956, were selected to investigate correlations between these SNPs and susceptibility to HCC. Two SNPs of the TRIM21 gene from 1196 controls without cancer and 394 HCC patients were analyzed using real-time polymerase chain reaction. These results were further analyzed to expound the associations between these TRIM21 polymorphisms and the risk of HCC as well as the impact of these SNPs on clinicopathological characteristics of HCC. After adjustment for other covariants, we observed that that younger patients (<65 years) with the TRIM21 rs915956 A allele had a probability of HCC (AOR = 3.153, 95% CI: 1.315–7.516, p = 0.010). Moreover, patients with a smoking habit who carried the T allele of rs4144331 had more probability of HCC (AOR = 2.940, 95% CI: 1.331–6.491, p = 0.008). In addition, we observed that the polymorphic T allele of rs4144331 led to distant metastasis. Thus, our findings suggest that genetic variations in TRIM21 may correlate to HCC and evaluate distant metastasis in patients with HCC.

Molecular and genetic characterization of hepatitis B virus among multitransfused thalassaemia patients in Islamabad, Pakistan

Background:

Hepatitis B virus (HBV) is the aetiological agent of transfusion-transmitted hepatitis globally. Beta thalassaemia major individuals are at greater risk of contracting HBV infection due to multiple blood transfusions required for the medical management of these patients. Based on HBV genetic variability, it is divided into 10 genotypes. The determination of HBV genotypes has significant implications for clinical management and treatment regimens.

Aim:

This study was performed to assess the HBV epidemiology and circulating genotypes in multi-transfused β-thalassemia major patients with the aim to be considered while formulating the treatment pattern taking into account particular needs of thalassaemia patients.

Materials and Methods:

This study was performed from September 2018 to June 2019, at the Department of Pathology and Transfusion Medicine, Shaheed Zulfiqar Ali Bhutto (SZAB) Medical University, Islamabad. A total of 2,260 thalassaemia patients were enrolled in the study. The study was endorsed by the Ethics Committee of the SZAB Medical University, Islamabad. The samples were serologically screened for HBsAg on the LIAISON® XL Murex HBsAg Quant assay (DiaSorin S.p.A., Italy) a chemiluminescence based immunoassay (CLIA). HBV quantitative PCR kit was used to measure the HBV DNA in serum samples. The HBV genotypes were determined using universal primers targeting the P1 and S1 region amplification.

Results:

Of 2,260 thalassaemia patients, 64.6% were males while 35.4% were females. The HBsAg was identified in 98 individuals (4.33%). The PCR analysis was done for these 98 patients and in this cohort, genotype D was 59.18% (n = 58), genotype A was 21.42% (n = 21) while genotype C was 19.38% (n = 19).

Conclusion:

The determination of HBV genotypes in the multi-transfused patients is key to the effective management of chronic HBV patients as the severity and course of the disease is dependent on a specific type of genotypes. Quality assured screening of donated blood will prevent the incidence of HBV in thalassaemia patients.

Genome-wide association study of the TP53 R249S mutation in hepatocellular carcinoma with aflatoxin B1 exposure and infection with hepatitis B virus

BACKGROUND

Exposure to dietary aflatoxin B1 (AFB1) induces DNA damage and mutation in the TP53 gene at codon 249, known as the TP53 R249S mutation, and is a major risk factor for hepatocellular carcinoma (HCC). AFB1 and the hepatitis B virus (HBV) together exert synergistic effects that promote carcinogenesis and TP53 R249S mutation in HCC.

METHODS

A genome-wide association study (GWAS) of whole genome exons was conducted using 485 HCC patients with chronic HBV infection. This was followed by an independent replication study conducted using 270 patients with chronic HBV infection. Immunohistochemistry was used to evaluate TP53 expression in all samples. This showed a correlation between codon 249 mutations and TP53 expression. Susceptibility variants for the TP53 R249S mutation in HCC were identified based on both the GWAS and replication study. The associations between identified variants and the expression levels of their located genes were analyzed in 20 paired independent samples.

RESULTS

The likelihood of positive TP53 expression was found to be higher in HCC patients with the R249S mutation both in the GWAS (P<0.001) and the replication study (P=0.006). The combined analyses showed that the TP53 R249S mutation was significantly associated with three single nucleotide polymorphisms (SNPs): ADAMTS18 rs9930984 (adjusted P=4.84×10-6), WDR49 rs75218075 (adjusted P=7.36×10-5), and SLC8A3 rs8022091 (adjusted P=0.042). The TP53 R249S mutation was found to be highly associated with the TT genotypes of rs9930984 (additive model, P=0.01; dominant model, P=6.43×10-5) and rs75218075 (additive model, P=0.002; dominant model, P=2.16×10-4). Additionally, ADAMTS18 mRNA expression was significantly higher in HCC tissue compared with its expression in paired non-tumor tissue (P=0.041), and patients carrying the TT genotype at rs9930984 showed lower ADAMTS18 expression in non-tumor tissue compared with patients carrying the GT genotype (P=0.0028). WDR49 expression was markedly lower in HCC tissue compared with paired non-tumor tissue (P=0.0011).

CONCLUSIONS

TP53 expression is significantly associated with the R249S mutation in HCC. Our collective results suggest that rs9930984, rs75218075, and rs8022091 are associated with R249S mutation susceptibility in HCC patients exposed to AFB1 and HBV infection.

Hepatitis B Virus Genotypes in the Kingdom of Bahrain: Prevalence, Gender Distribution and Impact on Hepatic Biomarkers

Background: Approximately 400 million people are infected with Hepatitis B virus (HBV) around the world, which makes it one of the world’s major infectious diseases. The prevalence of HBV genotypes and predictive factors for risk are poorly known in the Kingdom of Bahrain. Objectives: The aim of the present study was to investigate the prevalence of HBV genotypes, its correlation with demographic factor sand impacts on hepatic biomarkers. Materials and Methods: Venous blood samples were collected from 82 HBV positive patients (48 males, 34 females). The extraction of HBV DNA, PCR amplification, and genotyping were done to classify different genotypes (A, A/D, B, B/D, C, D, D/E, E). HBV genotypes association with gender, nationality, mode of transmission, and liver cirrhosis complication was determined by descriptive statistic and univariate analysis of variance (ANOVA). For liver function test, unpaired t-test and ANOVA were performed. Results: The predominant genotype among patients under study was genotype D (61%), followed by genotype A (10%), and lowest frequency was found for undetermined genotype (1%). In general, there was no significant association between the different genotypes and some demographical factors, serological investigations, and liver function test. The prevalence of HBV genotypes was higher in male patients as compared to female patients and higher in non-Bahraini than in Bahraini. Patients with the dominant genotype D showed higher than the normal maximum range for alanine aminotransferase (ALT) (mean = 45.89) and Gamma-glutamyl transferase (GGT) (mean = 63.36). Conclusions: The most common HBV genotype in Bahrain was genotype D, followed by genotype A. Further studies involving the sources of transmission and impact of hepatic biomarker in Bahrain are required to enhance the control measures of HBV infections.

FUT2 genetic variants as predictors of tumor development with hepatocellular carcinoma

Lewis antigens related to the ABO blood group are fucosylated oligosaccharides and are synthesized by specific glycosyltransferases (FUTs). FUTs are involved in various biological processes including cell adhesion and tumor progression. The fucosyltransferase-2 gene (FUT2) encodes alpha (1,2) fucosyltransferase, which is responsible for the addition of the alpha (1,2)-linkage of fucose to glycans. Aberrant fucosylation occurs frequently during the development and progression of hepatocellular carcinoma (HCC). However, the association of FUT2 polymorphisms with HCC development has not been studied. Therefore, we aimed to investigate the association of FUT2 polymorphisms with demographic, etiological, and clinical characteristics and with susceptibility to HCC. In this study, a total of 339 patients and 720 controls were recruited. The genotypes of FUT2 at four single-nucleotide polymorphisms (SNPs; rs281377, rs1047781, rs601338, and rs602662) were detected by real-time polymerase chain reaction from these samples. Compared with the wild-type genotype at SNP rs1047781, which is homozygous for nucleotides AA, at least one polymorphic T allele (AT or TT) displayed significant association with clinical stage (p = 0.048) and tumor size (p = 0.022). Our study strongly implicates the polymorphic locus rs1047781 of FUT2 as being associated with HCC development.

24 year outcomes of hepatitis B vaccination in Hangzhou, China

To evaluate the impact of the universal infant HepB vaccination program on hepatitis B virus infection in Hangzhou, China. Hepatitis B incidences and HepB vaccination rates of Hangzhou from 1990 to 2003 were acquired from the historical paper-documents, while which were derived from China Information System for Diseases Control and Prevention and Zhejiang Information System for Immunization Program respectively from 2004 to 2013. A serology survey among person aged 0-59 y was conducted in Hangzhou in 2006. Participants were selected by stratified, multi-stage random sampling. Serum specimens were tested for HBsAg, anti-HBs , anti-HBc , HBeAg and anti-HBe by ELISA. For the past 24 years, hepatitis B incidence and mortality of Hangzhou declined dramatically (χ(2) = 3.2 × 10(4); χ(2) = 172.443; both P for trend < 0.001). Both urban and rural incidence descended (χ(2)urban = 1.904 × 10(4); χ(2)rural = 1.633 × 10(4) ; both P for trend < 0.001).Hepatitis B patients mainly concentrated in 20-40 y old; workers and farmers were the main infection occupations, which was varies in different years (χ(2) = 1.619 × 10(3), P < 0.001). Significant association was found between incidence of hepatitis B and HepB vaccination rate (r = 0 .946, χ(2) = 11.813, Pfor trend = 0.001). A total of 5605 participants aged 0-59 y included in this serological survey. The prevalence of HBsAg, anti-HBs, anti-HBc, HBeAg and anti-HBe were 6.19%, 45.83%, 57.25%, 0.62%, and 4.37%, respectively. Hangzhou has successfully integrated the HepB into routine immunization programs and this has had a significant impact on decreasing the incidence of hepatitis B infection.

The p53 mutation spectrum in hepatocellular carcinoma from Guangxi, China : role of chronic hepatitis B virus infection and aflatoxin B1 exposure

BACKGROUND & AIMS

p53 is one of the most frequently mutated human tumour suppressor genes. Chronic infection with hepatitis B virus (HBV) and exposure to aflatoxin B1 (AFB1) induces p53 mutations in hepatocellular carcinoma (HCC) tissue. The aims of present study are to investigate the p53 mutation spectrum in HBV- and AFB1-related hepatocarcinogenesis in patients with hepatocellular carcinoma (HCC) in Guangxi, China.

METHODS

Tumour and adjacent liver tissue were collected from 397 HCC patients who were subdivided into HBV(+)/AFB1(+), HBV(+)/AFB1(-), HBV(-)/AFB1(+) and HBV(-)/AFB1(-) four groups. All 11 exons of the p53 gene were PCR-amplified and sequenced. Immunohistochemistry was used to evaluate the effect of mutations on the expression of p53 protein.

RESULTS AND CONCLUSIONS

P53 mutations were detected in 223 HCC samples, 13 adjacent liver tissue samples and only 1 of 68 normal liver tissue samples. The mutation sites concentrated at exon 4, 5, 6, 7, 8, 9 and no mutation was detected in exon 1, 2, 3, 10 and 11. The most frequently occurring mutation was in codon 249 (R249S) in exon 7. Patients in the HBV(+)/AFB1(+) and HBV(-)/AFB1(+) groups had significantly higher mutation rates compared with patients in the HBV(+)/AFB1(-) and HBV(-)/AFB1(-) groups. P53 mutation status and HBV/AFB1 status were independent predictors of tumour recurrence after surgery. Immunohistochemical analysis revealed that p53 gene mutations were correlated with the p53 expression. In Guangxi area, the significant association between AFB1-induced p53 mutations and the expression of p53 protein suggest an important role for p53 mutations in carcinogenesis of HCC.

Risk factors of hepatitis C virus transmission and genotype distribution in former blood donors from Chinese rural area

Background

Illegal commercial plasma and blood donation activities in the late 1980s and early 1990s caused a large number of hepatitis C virus (HCV) infections in rural areas of China. In the present study, we aimed to elucidate the risk factors of HCV RNA positivity and HCV genotype distribution in former blood donors.

Methods

A cross-sectional survey was carried out in a former blood donation village in rural Hebei Province, North China. All residents were invited for a questionnaire interview and testing for HCV antibodies as well as HCV nucleic acids. Questionnaires were administered to collect information about their personal status and commercial blood donation history. Nested PCR was used to amplify HCV nucleic acids in C/E1 region and NS5b region followed by genotyping and phylogenetic analysis. Univariate and multivariate logistic regression were used to analyze the distributions of HCV genotypes in different groups.

Results

A total of 512 blood samples were collected. Anti-HCV positive were 148 (28.5%) whereas RNA positive rate was 13.87%. Residents between 50 and 59 years old had the highest RNA positive rate (27/109, 24.77%) (P = 0.0051). Multivariate logistic regression model analysis revealed that plasma donation (OR = 8.666, 95% CI: 1.390-54.025) was the dominant risk factor of HCV infection. Furthermore, HCV subtypes 1b and 2a were found by genotyping and phylogenetic analysis. 36 samples (53.73%) were subtype 1b and 31 samples (46.27%) were subtype 2a.

Conclusions

Unsafe practices during illegal plasma donation led to a high risk of HCV infection. The identification of genotypes 1b and 2a as major HCV genotypes circulating in this region may help to predict the future burden of HCV related diseases and facilitate better medical treatment towards HCV carriers. These results are useful for public healthcare as well as disease control and surveillance.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-015-1535-6) contains supplementary material, which is available to authorized users.

Comparison of evolutionary patterns of different HBeAg status in HBV genotype B and C

The aim of this work was to investigate the different evolutionary patterns between HBeAg(+) and HBeAg(-) status of genotype B and genotype C of Hepatitis B virus (HBV). Complete HBV genome sequences were obtained from GenBank, and were classified as HBeAg(+) of genotype B, HBeAg(-) of genotype B, HBeAg(+) of genotype C, and HBeAg(-) of genotype C. The results showed that genotype B had lower diversity and a longer phylogenetic tree than genotype C. This means that genotype B was more conserved than genotype C. The genetic distance of HBeAg(+) was shorter than that of HBeAg(-) in genotype B. dN, dS, dN/dS of HBeAg(+) were lower than that of HBeAg(-). In addition, the Core and S genes had lower diversity, and were under lower selective pressure than other genes. We propose that by having different HBeAg HBV receives disparate immune selective pressures, however these different genotypes also receive disparate natural selective pressures. The evolutionary pattern of HBV could be one of the important factors that may affect viral replication in HBV infected patients and could therefore play an important role in the diseases progression.

Hepatitis C virus genotypes and association with viral load in yazd, central province of iran

BACKGROUND

Hepatitis C virus (HCV) is a major cause of liver disease. Infection with HCV is a global public health problem. The virus is classified into 6 genotypes and more than 80 subtypes named as a, b, c, etc. HCV genotyping has been an important parameter for the treatment of HCV infection.

OBJECTIVES

The main aim of this study was to estimate the prevalence of HCV genotypes in Yazd, central province of Iran. In addition, the study investigated whether there was any association between HCV load and genotypes.

PATIENTS AND METHODS

This descriptive cross-sectional study was performed on samples suspicious of HCV infection from March 2010 to June 2013. Peripheral blood sample was obtained and screened for anti-HCV antibodies using Enzyme-Linked Immunosorbent Assay (ELISA). Then sera of anti-HCV positive samples were analyzed using quantitative polymerase chain reaction method. Plasma samples were used to determine the HCV genotypes of 1a, 1b, 2, 3, and 4 in 191 infected patients.

RESULTS

One hundred fifty-two out of 191 (79.6%) samples were from male patients. The mean of the patients' age was 40.7 ± 11.9 years (range 21-75 years old). Sixty- three (33%) patients were included in 31-40 years group. The mean number of HCV in infected patients was 2.92 × 10(6) ± 1.85 × 10(6) copies/mL (Min: 508; Max: 2.75 × 10(8) copies/mL). HCV genotype 3 was the predominant genotype (50.3%) followed by subtypes 1a (38.7%) and 1b (6.8%). The distribution of other HCV genotypes showed genotype 2 in 1.6% and mixed genotypes in 2.6% of positive samples. Genotype 3 was predominant in all age groups except 21-30 years of age group. We were unable to find any significant difference between mean viral load of the patients infected with genotype 3 and those infected with genotype 1 (1a and 1b).

CONCLUSIONS

Findings of the present study showed that HCV genotype 3 was the predominant genotype followed by the subtypes 1a and 1b in Yazd, central province of Iran. In addition, there was no difference between HCV load and genotypes 1 and 3. HCV genotyping is recommended in other provinces of Iran.

Performance of two real-time PCR assays for hepatitis B virus DNA detection and quantitation

In-house developed real-time PCR (qPCR) techniques could be useful conjunctives to the management of hepatitis B virus (HBV) infection in resource-limited settings with high prevalence. Two qPCR assays (qPCR1 and qPCR2), based on primers/probes targeting conserved regions of the X and S genes of HBV respectively, were evaluated using clinical samples of varying HBV genotypes, and compared to the commercial Roche Cobas AmpliPrep/Cobas TaqMan HBV Test v2.0. The lower detection limit (LDL) was established at 104 IU/ml for qPCR1, and 91 IU/ml for qPCR2. Good agreement and correlation were obtained between the Roche assay and both qPCR assays (r = 0.834 for qPCR1; and r = 0.870 for qPCR2). Differences in HBV DNA load of > 0.5 Log10 IU/ml between the Roche and the qPCR assays were found in 49/122 samples of qPCR1, and 35/122 samples of qPCR2. qPCR1 tended to underestimate HBV DNA quantity in samples with a low viral load and overestimate HBV DNA concentration in samples with a high viral load when compared to the Roche test. Both molecular tools that were developed, used on an open real-time PCR system, were reliable for HBV DNA detection and quantitation. The qPCR2 performed better than the qPCR1 and had the additional advantage of various HBV genotype detection and quantitation. This low cost quantitative HBV DNA PCR assay may be an alternative solution when implementing national programmes to diagnose, monitor and treat HBV infection in low- to middle-income countries where testing for HBV DNA is not available in governmental health programmes.

Hepatitis C virus genotyping methods: evaluation of AmpliSens(®) HCV-1/2/3-FRT compared to sequencing method

BACKGROUND

Hepatitis C virus (HCV) genotyping is important for treatment and epidemiological purposes. The objective of this study was to evaluate the performance of AmpliSens(®) HCV-1/2/3-FRT kit in comparison to sequencing method for genotyping.

METHODS

A total of 17 samples collected from December 2009 to January 2011 were analyzed. Reverse transcriptase polymerase chain reaction (PCR) was performed, followed by sequencing technique. Results were analyzed based on sequence information in GenBank. A second genotyping method (AmpliSens(®) HCV-1/2/3-FRT) was done, which differentiates HCV genotypes by means of real-time hybridization-fluorescence detection.

RESULTS

From 17 samples, four were untypeable by AmpliSens(®) HCV-1/2/3-FRT. Eleven of 13 (84.6%) results showed concordant genotypes. A specimen that was determined as genotype 3a by sequencing was genotype 1 by the AmpliSens(®) HCV-1/2/3-FRT. Another specimen that was genotype 1 by sequencing was identified as genotype 3 by AmpliSens(®) HCV-1/2/3-FRT.

CONCLUSION

HCV genotyping with AmpliSens(®) HCV-1/2/3-FRT using real-time PCR method provides a much simpler and more feasible workflow with shorter time compared to sequencing method. There was good concordance compared to sequencing method. However, more evaluation studies would be required to show statistical significance, and to troubleshoot discordant results. AmpliSens(®) HCV-1/2/3-FRT does differentiate between genotype but not until subtype level.

New Epitope Peptides Derived from Hepatitis C Virus (HCV) 2a Which Have the Capacity to Induce Cytotoxic T Lymphocytes in HLA-A2+HCV-Infected Patients

Because cytotoxic T lymphocytes (CTLs) play an important role in the specific immunotherapy of hepatitis C virus (HCV) infection, a series of CTL epitopes has been defined from HCV genotype 1a or 1b protein. Here, we attempted to identify HCV2a-derived epitopes that are capable of inducing HLA-A2-restricted and peptide-specific CTLs. Peripheral blood mononuclear cells (PBMCs) of HLA-A2+ HCV2ainfected patients or healthy donors were stimulated in vitro with each of the HCV2a-derived peptides, which were prepared based on the HLA-A2-binding motif, and their peptide-specific and HLA-A2-restricted cytotoxicities were examined. The HCV2a 432-441, HCV2a 716-724, and HCV2a 2251-2260 peptides were found to efficiently induce peptide-specific CTLs from the PBMCs of HLA-A2+ HCV2ainfected patients. Cytotoxicity was mainly mediated by CD8+ T cells in a HLA class I-restricted manner. These results indicate that the HCV2a 432-441, HCV2a 716-724, and HCV2a 2251-2260 peptides might be applicable for peptide-based immunotherapy of HLA-A2+ HCV2a-infected patients.

Hepatitis B virus genotypes from European origin explains the high endemicity found in some areas from southern Brazil

Southern Brazil is considered an area of low Hepatitis B endemicity, but some areas of higher endemicity have been described in the Southwest of Paraná and Santa Catarina states. The aim of this study was to evaluate viral genotypes circulating throughout Paraná state. PCR amplification and partial sequencing of the S gene was carried out in 228 samples from HBsAg positive candidate blood donors. Samples have been collected in seven different counties (Cascavel, Curitiba, Foz do Iguaçu, Francisco Beltrão, Maringá, Londrina and Paranaguá). The most common HBV genotype in Paraná state was D (82.9%; 189/228), followed by A (14.1%; 32/228). Genotypes F (1.3%; 3/228), C (1.3%; 3/228) and H (0.4%; 1/228) were also found. Distribution of genotypes was different in the studied counties, but genotype D was the most frequent in all of them. In Francisco Beltrão, all studied samples belonged to genotype D. The high prevalence of HBV genotype D in South of Brazil is explained by the intense migration of settlers from Europeans countries. Subgenotypes A1 and A2 were identified circulating in all cities where HBV/A was found. As observed in other areas of Brazil, HBV/A1 is more frequent than the HBV/A2 in Paraná state and its presence was significantly larger in black and mulatto individuals. Genotype C was found only in individuals with Asian ancestry from Londrina and Maringá. Most HBV/F sequences identified in this study were classified as subgenotype F2a that was previously described in Brazil. The sole case of subgenotype F4 was from Foz do Iguaçu city, near to Northern Argentina, where F4 is highly prevalent. The single genotype H sample was from Curitiba. This is the first case of this genotype described in Brazil. Further studies should be carried out to determine if more genotype H samples can be found in other populations from Brazil.

Near-full genome characterization of unclassified hepatitis C virus strains relating to genotypes 1 and 4

Near-full genome sequences are presented in this report for the first time of unclassified HCV strains amplified using RT-PCR from plasma of patients living in Cyprus. One strain appears to be a unique genotype-1-like isolate, displaying closer phylogenetic relationship to genotype 1 strains than other genotypes. Two isolates representing an unclassified variant of genotype 4 were also amplified, cases of which have been found elsewhere in the world in patients of central African origin and could now be assigned provisionally as new subtype 4v. The near-full genome nucleotide sequences of unclassified HCV isolates provide reference sequences of variants unknown previously, and contribute to the publicly available HCV sequence data to be used for diagnosis or research.

Prevalence of HBV infection among different HIV-risk groups in Hai Phong, Vietnam

Hepatitis B virus (HBV) infection in Hai Phong, northern Vietnam, was characterized by analyzing the prevalence and genotype distribution of HBV as well as co-infection with human immunodeficiency virus type 1 (HIV-1) among five different risk groups for HIV infection. Plasma samples were collected from intravenous drug users (n=760, anti-HIV-1 antibody positive rate: 35.9%), female sex workers (FSWs; n=91, 23.1%), seafarers (n=94, 0%), pregnant women (n=200, 0.5%), and blood donors (n=210, 2.9%) in 2007 [Ishizaki et al. (2009): AIDS Res Hum Retroviruses 25:175-182]. Samples were screened for the hepatitis B surface antigen (HBsAg) and anti-HBs antibody and analyzed genetically. The cumulative HBV incidence rate (HBsAg+anti-HBs) was 53.2% (10.7+42.5%) in intravenous drug users, 51.6% (11.0+40.6%) in FSWs, 54.3% (9.6+44.7%) in seafarers, 50.5% (12.5+38.0%) in pregnant women, and 51.0% (18.1+32.9%) in blood donors; there was no significant difference among these groups. Of 163 HBsAg-positive samples, 113 could be analyzed genetically. Phylogenetic analysis, based on the preS1 region, revealed genotype B4 was most prevalent (90/113; 79.6%), followed by C1 (17.7%), I1 (1.8%), and B2 (0.9%). There was no significant difference in HBV genotype distribution among different HIV infection-risk groups. The prevalence of HBsAg was 10.3% (31/301) in HIV-1-infected individuals and 12.5% (132/1,054) in non-HIV-1-infected individuals, which was not significant. In addition, no significant difference in HBV genotype distribution was observed between HBV/HIV-1 coinfected and HBV mono-infected groups. These results suggest that, although HBV and HIV-1 share modes of transmission, major transmission routes of HBV have been different from those of HIV-1 in Hai Phong, Vietnam.

Molecular epidemiology of hepatitis C infection in Cyprus within the general population and high-risk cohorts

Background

Initial data on the molecular epidemiology of HCV infection in Cyprus showed a highly polyphyletic infection and multiple points of introduction into the general population. The continuation and expansion of this investigation is presented here including high risk groups.

Findings

The samples include additional subjects from the general population, a group of inmates and HIV/HCV coinfected individuals, whose strains were amplified by RT-PCR and sequenced in partial Core-E1 and NS5B regions. The results confirm the broad genotype distribution and polyphyletic infection on the island, and no new subtypes were found. Monophyletic clusters between strains of the prisoners and the injecting drug users imply sharing of infected equipment, and highlight the risk of widespread transmission in these cohorts, although no spill-over to the general population was observed.

Conclusions

The results of this study underline the impact of population movements and high-risk population groups on the changing molecular epidemiology of HCV, with strains moving to Europe from Asia, Africa and Eastern Europe by means of immigration and modern transmission routes.

Virologic and clinical characteristics of HBV genotypes/subgenotypes in 487 Chinese pediatric patients with CHB

Background

The association of hepatitis B virus (HBV) genotypes/subgenotypes with clinical characteristics is increasingly recognized. However, the virologic and clinical features of HBV genotypes/subgenotypes in pediatric patients remain largely unknown.

Methods

Four hundred and eighty-seven pediatric inpatients with CHB were investigated, including 217 nucleos(t)ide analog-experienced patients. HBV genotypes/subgenotypes and reverse transcriptase (RT) mutations were determined by direct sequencing. The stage of fibrosis and degree of inflammatory activity were evaluated by the Metavir score system.

Results

Among 487 enrolled pediatric patients, HBV genotype C2 and B2 were the most two prevalent (73.7% and 21.1%). Comparing with HBV/B2 infected patients, no significant difference was observed in the incidence rate and mutant patterns of lamivudine- or adefovir-resistant mutations in HBV/C2 infected patients (P > 0.05). Importantly, we found that the degree of hepatic inflammation degree, fibrosis stage and ALT level were significantly higher in HBV/C2-infected HBeAg positive patients than it was in HBV/B2-infected ones.

Conclusions

The pediatric patients with HBV/C2 infection might be more susceptible to develop severe liver pathogenesis.

T3098C and T53C mutations of HBV genotype C is associated with HBV infection progress

OBJECTIVE

To analyze the association between mutation(s) in preS region of HBV and hepatitis B disease progress in Chinese patients with genotype C chronic HBV infection.

METHODS

Ninety-three patients with chronic genotype C HBV infection, including 24 asymptomatic carriers (ASC), 26 patients with chronic hepatitis B (CHB), 22 patients with liver cirrhosis (LC) and 21 HCC patients were investigated. Levels of HBV DNA, HBeAg, alanine aminotransferase (ALT), asparate transaminase (AST) were measured. HBV preS region was analyzed by PCR direct sequencing.

RESULTS

The prevalence of preS T3098C and T53C mutations of genotype C HBV was significantly higher in LC and HCC patients than ASC and CHB patients. The rate of T3098C mutation in ASC, CHB, LC, and HCC patients were 0.00% (0/24), 3.85% (1/26), 9.09% (2/22), and 30.77% (8/22), respectively (P=0.0015), while the rate of T53C mutation was 12.50% (3/24), 3.85% (1/26), 40.91% (9/22), and 42.31% (11/26), respectively (P=0.0012).

CONCLUSION

The frequency of genotype C HBV preS T3098C and T53C mutations is associated with hepatitis B infection progression

Clinical evaluation of a colorimetric oligonucleotide chip for genotyping hepatitis C virus

INTRODUCTION

Hepatitis C virus (HCV) is a major cause of chronic liver disease worldwide. It is associated with the development of end-stage liver disease and hepatocellular carcinoma. Studies have shown that determination of hepatitis C virus (HCV) genotypes is clinically important for prediction of the clinical course and the outcome of antiviral therapy. The aim of this study was to evaluate a colorimetric oligonucleotide chip, which can be used for the rapid and economical detection of the genotypes/subtypes of hepatitis C virus.

DESIGN AND METHODS

A total of 860 serum specimens were tested by an oligonucleotide chip genotyping test. Partial genotype results were compared with those obtained by sequencing method and INNOLiPA HCV II assay. The relative sensitivities of the methods were assessed by using the 5'NCR amplicon from the HCV RNA fluorescent amplicor HCV tests and Light Cycler.

RESULTS

Of 860 serum specimens tested for their genotypes/subtypes by the oligonucleotide array, 607 HCV positive serum samples could be typed by the sequencing method and 60 of 607 HCV positive serum specimens were typed by INNOLiPA HCV II method. Identification of genotype/subtypes by nucleotide sequencing and INNOLiPA HCV II assay showed respective coincidence rates of 99.8% and 96.7% with the HCV oligonucleotide chip results. And the colorimetric method exhibited 99.8% of relative sensitivity compared with the fluorescent amplicor HCV tests.

CONCLUSION

To our knowledge this oligonucleotide chip genotyping method offers a fast and convenient way to determine the genotype in large-scale settings. The tests can be easily adapted by a clinical diagnostic laboratory.

Molecular epidemiology of hepatitis C infection in Cyprus: evidence of polyphyletic infection

The genetic diversity of the hepatitis C virus (HCV) in Cyprus is investigated for the first time in this study. Nucleotide sequence analysis of the CORE-E1 and NS5B regions of the HCV genome was performed on blood plasma samples obtained from 77 HCV patients in Cyprus, collected during 2005-2008. The amplified products were sequenced and compared to reference HCV strains of known genotype and subtype in order to classify the isolates found in this study. Genotype could be determined for all strains, and subtype for all but four isolates. Phylogenetic analysis revealed that 51 patients were genotype 1, of which 38 were subtype 1b, 9 were 1a, and 1 was unclassified, one patient was genotype 2c, 13 were genotype 3a, nine were genotype 4, of which six were subtype 4a, and three were of unclassified subtype, one was genotype 5a, two patients seem to carry a possible 2k/1b recombinant strain, and no genotype 6 strains were found. This study demonstrated a genetic heterogeneity of HCV infection in Cyprus, with five of the six known HCV genotypes on the island, including unclassified isolates in genotypes 1 and 4, and also the apparent introduction of the 2k/1b recombinant strain in intravenous drug users.

Ground glass hepatocytes contain pre-S mutants and represent preneoplastic lesions in chronic hepatitis B virus infection

The discovery of "ground glass" hepatocytes (GGH) that contain hepatitis B virus (HBV) surface antigens by Hadziyannis and Popper in 1973 represents a historical landmark in the pathology of chronic HBV infection. Different types of GGH have been correlated to the expression patterns of surface/core antigens and the stages of virus replication. The original two types (designated types I & II) of GGH were found to contain specific pre-S mutants with deletions over either pre-S1 or pre-S2 regions, respectively. Type II GGH consistently harbor pre-S2 deletion mutants, which can escape from immune attack and grow preferentially to form clusters. Both types of pre-S mutants can induce endoplasmic reticulum (ER) stress and oxidative DNA damage. The pre-S2 mutants, albeit inducing a weaker level of ER stress signals, could additionally initiate ER stress-independent retinoblastoma/adenovirus E2 promoter binding factor/cyclin A signaling through their interaction with c-Jun activation domain binding protein 1 to degrade p27, illustrating the growth advantage of type II GGH. The combined effects of genomic instability and the proliferation of hepatocytes harboring pre-S mutants could potentially lead to hepatocarcinogenesis over the decades of chronic HBV infection. The presence of pre-S mutants in sera was reported to carry a high risk of developing hepatocellular carcinoma (HCC). Furthermore, transgenic mice harboring pre-S2 mutant plasmids have been shown to develop a dysplastic change of hepatocytes and HCC. Therefore, in addition to being a histological marker of chronic HBV infection, GGH, particularly type II GGH, may represent the preneoplastic lesions of HBV-related HCC.

New complex recombinant genotype of hepatitis B virus identified in Vietnam

A novel variant of hepatitis B virus was identified in Vietnam. This strain (HBV-VH24) had a novel intergenotypic recombination between genotypes A, C, and G. VH24 showed high similarity (98.3 to 98.9%) to the "aberrant strains" among Vietnamese isolates reported by Hannoun et al. (C. Hannoun et al., J. Gen. Virol. 81:2267-2272, 2000) and also had similar breakpoints of recombination. Phylogenetic analysis of the complete genome of these strains formed a separate clade. Furthermore, their pre-S/S gene-encoded seven unique conserved amino acid residues were not present in other genotypes. These findings support the designation of the new genotype I.

Hepatitis B virus infection contributes to oxidative stress in a population exposed to aflatoxin B1 and high-risk for hepatocellular carcinoma

Biomarkers of hepatitis B virus (HBV) infection, aflatoxin B1 (AFB1) exposure and oxidative stress were detected in 71 hepatocellular carcinoma (HCC) patients and 694 controls from southern China. Plasma level of AFB1-albumin-adducts (AAA) and protein carbonyl content (PCC) were significantly higher in the 71 HCC cases than in any age/gender matched HBV sero-status groups (p<0.001). HCC patients positive for the p53-249 G-T mutation had a marginally higher level of PCC than those negative for the mutation (p=0.077). HBV infection had a prominent influence on the association between AFB1 exposure and oxidative stress biomarkers in the controls. Our study indicates a significant contribution from HBV infection to oxidative stress in a population with AFB1 exposure which might substantially increase risk for HCC in this region.

Hepatitis B virus (HBV) genotype and YMDD motif mutation profile among patients infected with HBV and untreated with lamivudine

OBJECTIVES

A few reports exist on hepatitis B virus (HBV) genotype distribution in Iran; however the sample sizes of these studies are insufficient. The first objective of this study was to determine the HBV genotype distribution with a large sample size (147 specimens). The second objective was to determine the incidence of the lamivudine-resistant YMDD mutant profile among HBV-infected patients not treated with lamivudine; some studies have reported that YMDD mutants are detectable even before antiviral treatment.

METHODS

We used two cost-effective PCR-based methods that have been developed in-house: gap-PCR and artificially created restriction site-PCR (ACRS-PCR). Also, 11 samples were randomly selected and bi-directionally sequenced and subjected to phylogenetic analysis.

RESULTS

Gap-PCR results revealed genotype D of HBV in all patients, and ACRS-PCR results disclosed the absence of mutation within the YMDD motif before antiviral therapy in the study population. Phylogenetic analysis supported the former genotyping results with the segregation of all Iranian HBV isolates in the genotype D branch with a high bootstrap value (99%, 1000 replicates).

CONCLUSIONS

The present study using two cost-effective methods showed that genotype D of HBV is dominant among Iranian HBV-infected subjects, and HBV lamivudine-resistant strains do not exist naturally among Iranian patients not treated with lamivudine.

Hepatitis B virus genotypes in children and adolescents in Japan: before and after immunization for the prevention of mother to infant transmission of hepatitis B virus

The genotype distribution of hepatitis B virus (HBV) was investigated in 118 children in Japan. One hundred and sixteen children (98%) had chronic HBV infection, and the remainder had acute hepatitis. Genotyping of HBV was determined by PCR and sequencing analysis in the S gene. Genotype C (86%) was the most frequent, followed by genotype B (9%), D (2.5%), and A (1.0%). Transmission routes of HBV to children were from mothers in 91 patients (77%), fathers in 8 (6.5%), mother or father in 1 (1%), family members other than the parents in 5 (4%), and unknown in 13 (11.5%). The relationship between routes of HBV transmission and HBV genotypes was studied. Eighty-eight (97%) of 91 children of mother-to-infant transmission were genotype C, while 13 (49%) of 27 children of the routes other than the mother to infant transmission were genotype C. The number of children with genotype C who were infected from their mothers was significantly higher than those with genotype B, D, or A (P < 0.01). In conclusion, HBV genotypes influence not only clinical characteristics but also the mechanisms of inter-personal HBV transmission.

Hepatitis C virus genotype distribution in Myanmar: Predominance of genotype 6 and existence of new genotype 6 subtype

AIM

This study was performed to determine the prevalence and distribution of hepatitis C virus (HCV) genotypes in Myanmar.

METHODS

A total of 1333 peripheral blood samples were collected from four different border cities of Myanmar. The anti-HCV antibody-positive serum samples were identified. HCV was genotyped by reverse transcriptase polymerase chain reaction, direct DNA sequencing and phylogenetic analysis on the partial core genome.

RESULTS

The overall prevalence of HCV infection was 11.6% (154/1333). Regionally, it was 13.5% (47/349) in the north-eastern city, 12.8% (64/501) in the north-western city, 4.2% (16/380) in the southern city and 26.2% (27/103) in the western city. HCV was genotyped in 145/154 (94.2%) samples. Genotype 6 was the most prevalent genotype in this study (71/145, 49%), followed by genotype 3 (57/145, 39.3%), genotype 1 (16/145, 11%), and genotype 2 (1/145, 0.7%). Genotype 6 was mostly found in the northern cities and genotype 3 in the southern and western cities of Myanmar. Multiple HCV genotypes/subtypes were successfully characterized as 1a, 1b, 2a, 3a, 3b, 6m, 6n, and a new 6 subtype. Among them, subtype 6n was the most predominant subtype (38.6%), followed by subtype 3b (29.7%), 3a (9.6%), 6m (9%), 1b (6.9%), 1a (4.1%), new 6 subtype (1.4%) and 2a (0.7%). Subtype 6n was more widely distributed in the northern cities whereas subtype 3b was more common in the western city. The newly discovered genotype 6 subtype was from the northern cities.

CONCLUSIONS

The results indicate there are regional differences of HCV genotype distribution in Myanmar. There is a distinct geographic variation from other South-East Asian countries in terms of the existence of the new genotype 6 subtype.

Preliminary report of hepatitis B virus genotype prevalence in Iran

AIM: To determine the prevalence of hepatitis B virus (HBV) genotypes in Iranian hepatitis B surface antigen (HBsAg) carriers, chronic hepatitis B and cirrhotic patients.

METHODS: A total of 109 HBsAg-positive patients were included in this study. HBV genotypes were determined by using INNO-LiPA methodology which is based on the reverse hybridization principle.

RESULTS: The distribution of patients with different stages of liver disease was as follows: 95 (86.4%) chronic hepatitis, 11 (10%) liver cirrhosis, and 3 (2.7%) inactive carrier. Of the chronic hepatitis and liver cirrhosis patients, 26.4% were HBeAg-positive while 70% were HBeAg-negative. Genotype D was the only detected type found in all patients.

CONCLUSION: Classifying HBV into genotypes has to be cost-effective and clinically relevant. Our study indicates that HBV genotype D prevails in the Mediterranean area, Near and Middle East, and South Asia. Continued efforts for understanding HBV genotype through international co-operation will reveal further virological differences of the genotypes and their clinical relevance.

Phylogenetic, virological, and clinical characteristics of genotype C hepatitis B virus with TCC at codon 15 of the precore region

Hepatitis B virus (HBV) with T-1856 of the precore region is always associated with C-1858 (i.e., TCC at nucleotides 1856 to 1858), and it is reported only in genotype C HBV isolates. We aimed to investigate the phylogenetic, virological, and clinical characteristics of HBV isolates bearing TCC at nucleotides 1856 to 1858. We have previously reported on the presence of two major subgroups in genotype C HBV, namely, HBV genotype Cs (Southeast Asia) and HBV genotype Ce (Far East). We have designed a novel 5' nuclease technology based on the nucleotide polymorphism (C or A) at nucleotide 2733 to differentiate the two genotype C HBV subgroups. The mutations at the basal core promoter and precore regions were analyzed by direct sequencing. Among 214 genotype C HBV-infected patients, 31% had TCC, 37% had CCC, 3% had CTC, and 29% had CCT at nucleotides 1856 to 1858. All except one HBV strain with TCC at nucleotides 1856 to 1858 belonged to subgroup Cs, which has been reported only in Hong Kong; Guangzhou, China; and Vietnam. HBV with TCC at nucleotides 1856 to 1858 was associated with the G1898A mutation (64%). Patients infected with HBV harboring TCC had more liver cirrhosis than those infected with HBV harboring CCC (18% versus 5%; P = 0.008), and more of the patients infected with HBV harboring TCC were positive for HBeAg (58% versus 36%; P = 0.01) and had higher median alanine aminotransferase levels (65 IU/liter versus 49 IU/liter; P = 0.006); but similar proportions of patients infected with HBV harboring TCC and those infected with HBV harboring CCT had liver cirrhosis (18% versus 13%; P = 0.43). In summary, we report that HBV with TCC at nucleotides 1856 to 1858 of the precore region might represent a specific HBV strain associated with more aggressive liver disease than other genotype C HBV strains.

Identification of hepatitis C virus (HCV) 2a-derived epitope peptides having the capacity to induce cytotoxic T lymphocytes in human leukocyte antigen-A24+ and HCV2a-infected patients

Since virus-specific cytotoxic T lymphocytes (CTLs) play a critical role in preventing the spread of hepatitis C virus (HCV), vaccine-based HCV-specific CTL induction could be a promising strategy to treat HCV-infected patients. In this study, we tried to identify HCV2a-derived epitopes, which can induce human leukocyte antigen (HLA)-A24-restricted and peptide-specific CTLs. Peripheral blood mononuclear cells of HCV2a-infected patients or healthy donors were stimulated in vitro with HCV2a-derived peptides, which were prepared based on the HLA-A24 binding motif. As a result, three peptides (HCV2a 576-584, HCV2a 627-635, and HCV2a 1085-1094) efficiently induced peptide-specific CTLs from HLA-A24(+) HCV2a-infected patients as well as healthy donors. The cytotoxicity was exhibited by peptide-specific CD8(+) T cells in an HLA-A24-restricted manner. In addition, the HCV2a 627-635 peptide was frequently recognized by immunoglobulin G of HCV2a-infected patients. These results indicate that the identified three HCV2a peptides might be applicable to peptide-based immunotherapy for HLA-A24(+) HCV2a-infected patients.

Epidemiology of hepatitis C virus (HCV) infection

Hepatitis C virus remains a large health care burden to the world. Incidence rates across the world fluctuate and are difficult to calculate given the asymptomatic, often latent nature of the disease prior to clinical presentation. Prevalence rates across the world have changed as well with more countries aware of transfusion-related hepatitis C and more and more evidence supporting intravenous drug use as the leading risk factor of spread of the virus. This article reviews current hepatitis C virus prevalence and genotype data and examines the different risk factors associated with the virus.

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Autonomous activation of hepatitis B virus large surface protein

AIM: To construct the yeast expression vector of hepatitis B virus large surface protein (LHBs), and to study its autonomous activation.

METHODS: The Matchmaker GAL4 two-hybrid technique was used. The LHBs, pre-S1, pre-S2 and SHBs genes were amplified by polymerase chain reaction (PCR) with respective primers. The amplified PCR fragments were then subcloned into the EcoR I/BamH I sites (5'ands) of pGBKT7 vector to obtain the expression vectors including pGBKT7(-)-LHBs, pGBKT7(-)-preS1, pGBKT7(-)-preS2 and pGBKT7(-)-SHBs. This vectors were identifed by PCR and digestion of EcoR I/BamH I. After the constructed vectors were transformed into yeast AH109, the yeast cells were plated on synthetic dropout nutrient medium (SD/-Trp and SD/-Trp-His-Ade) containing x-a-gal for testing their autonomous activation.

RESULTS: The yeast expression vectors were constructed. The yeast cells transformed with pGBKT7-LHB and pGBKT7-preS1 vectors could grow well on both of the media. However, cells transformed with pGBKT7-preS2 and pGBKT7-SHBs vectors could only grow on the SD/-Trp medium.

CONCLUSION: The LHBs functions as a transcriptional transactivator, and serves as the functional GAL4 activation domain (AD) to activate transcription of reporter genes (ADE2, HIS3, MEL1 and LacZ). The autonomous activation of LHBs roots in its pre-S1 domain.