Genotyping of hepatitis B virus isolated from chronic hepatitis B patients in the south of Turkey by DNA cycle-sequencing method

A Recent Prevalence of Hepatitis B Virus (HBV) Genotypes and Subtypes in Asia: A Systematic Review and Meta-Analysis

Background and Aim: Despite introducing the hepatitis B virus (HBV) vaccine, the incidence of the Hepatitis B virus globally is still a major health concern. This systematic review and meta-analysis were conducted to provide detailed information on the prevalence of HBV genotypes and subtypes in circulation in Asia. Methods: A systematic search for articles describing the prevalence of HBV genotypes and subtypes in Asia was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. Results: Our search returned 207 eligible articles involving 49,279 genotypes and 7457 subtypes representing 28 Asian countries. A meta-analysis was performed on our eligible studies using the Random effect Model. The pooled prevalence of HBV genotypes showed that genotype C (30.9%) (95% CI, 27.5–34.5%; I2 = 97.57%; p < 0.001) was the most common HBV genotype in Asia, followed by genotype B (17.8%) (95% CI, 15.5–20.4%; I2 = 97.26%; p < 0.001) and genotype D (15.4%) (95% CI, 11.8–19.8%). Vietnam had the highest prevalence of genotype B, Lebanon had the highest prevalence of genotypes C, and Jordan had the highest prevalence of genotype D. There was variation in genotypic prevalence with respect to the target genes for HBV genotyping. Reverse dot blot hybridization had the highest estimate of genotypes B and C. HBV subtype C2 (40.0%) (95% CI, 33.3–47.0) is the most prevalent HBV subtype. Conclusion: Evidence from this study reveals that HBV genotypes C and B are the most dominant HBV genotypes in Asia, and HBV subtype C2 is more endemic in Asia.

Characterization of hepatitis B virus in Turkish blood donors, and the prevalence of the SP1 splice variant

Hepatitis B is a disease of the liver that can manifest acutely, or persist chronically as a result of infection with the hepatitis B virus (HBV). Turkey has a moderate endemicity level of HBV infection, and all data published to date has shown this to be of genotype D, predominantly of subgenotype D1. However the sequences of very few full genomes have been published. The aim of this study was to characterize the molecular profile of hepatitis B virus in asymptomatic, first-time Turkish blood donors. The results confirm that genotype D, subgenotype D1 is the most prevalent HBV strain in Turkey, accounting for 94% of cases. Subgenotypes D2 and D3 were present as minority strains (4% and 2%, respectively). A singly spliced HBV variant that is capable of forming defective HBV particles and has been associated with apoptosis and activation of T-cell responses was also detected in 52.5% of samples screened, co-circulating with wild type genomes.

Molecular analysis of HBV genotypes and subgenotypes in the Central-East region of Tunisia

Background

In Tunisia, country of intermediate endemicity for Hepatitis B virus (HBV) infection, most molecular studies on the virus have been carried out in the North of the country and little is known about other regions. The aim of this study was to determine HBV genotype and subgenotypes in Central-East Tunisia. A total of 217 HBs antigen positive patients were enrolled and determination of genotype was investigated in 130 patients with detectable HBV DNA. HBV genotyping methods were: PCR-RFLP on the pre-S region, a PCR using type-specific primers in the S region (TSP-PCR) and partial sequencing in the pre-S region.

Results

Three genotypes (D, B and A) were detected by the PCR-RFLP method and two (D and A) with the TSP-PCR method, the concordance between the two methods was 93%. Sequencing and phylogenetic analysis of 32 strains, retrieved the same genotype (D and A) for samples with concordant results and genotype D for samples with discordant results. The sequences of discordant genotypes had a restriction site in the pre-S gene which led to erroneous result by the PCR-RFLP method. Thus, prevalence of genotype D and A was 96% and 4%, respectively. Phylogenetic analysis showed the predominance of two subgenotypes D1 (55%) and D7 (41%). Only one strain clustered with D3 subgenotype (3%).

Conclusions

Predominance of subgenotype D7 appears to occur in northern regions of Africa with transition to subgenotype D1 in the East of the continent. HBV genetic variability may lead to wrong results in rapid genotyping methods and sequence analysis is needed to clarify atypical results.

Geographical and genetic diversity of the human hepatitis B virus

Hepatitis B virus (HBV) is one of the most widely distributed viruses that infect humankind. Distinct clinical and virological characteristics of the HBV-infection have been reported in different geographical parts of the world and are increasingly associated with genetic diversity of the infecting virus. HBV is classified into genotypes and subgenotypes that are associated with ethnicity and geography. The genetic diversity of HBV in its various aspects has been the subject of extensive investigations during the last few decades. Since molecular epidemiology research tools have become widely available, the number of new publications in this field has grown exponentially. This review summarises the recent publications on the geographical distribution of genetic variants of HBV, and proposes updated criteria for the identification of new genotypes and subgenotypes of the virus.

Naturally occurring amino-acid substitutions to nucleos(t)ide analogues in treatment naive Turkish patients with chronic hepatitis B

Naturally occurring amino-acid substitutions in the hepatitis B virus (HBV) polymerase gene may be responsible for resistance to nucleoside/nucleotide (NUCs) analogues. To date, only pre-existing lamivudine resistance has been extensively studied. The aim of the present study was to determine the naturally occurring or pre-existing amino-acid substitutions related to NUCs in treatment naive Turkish patients with chronic hepatitis B (CHB). The investigation involved a total of 88 patients (65 males and 23 females; mean age, 34 years; range, 15-61 years) who were diagnosed with CHB between April 2008 and January 2009. According to HBeAg status, 66 patients were HBeAg-negative and 22 patients were HBeAg positive. Naturally occurring substitutions in the HBV polymerase region were detected by DNA sequencing in 17 (19%) and 30 (34%) patients, based on manual and geno2pheno tool database interpretation, respectively. Each amino-acid substitution appeared alone and included rtA194T, rtV214A, rtQ215S, rtI233V and rtN236T. The median values for viral load, ALT and AST were 3.3 log(10) (2.0-6.0) IU/mL, 36 (12-515) U/L and 27 (13-284) U/L, respectively, but these did not correlate with the observed amino-acid substitutions in the polymerase region. By direct sequencing, genotype D of HBV was found to still be dominant among Turkish patients. In conclusion, every patient who is diagnosed with CHB should be monitored before the start of treatment for more effective management of patient treatment options.

Liver steatosis in patients with chronic hepatitis B infection: host and viral risk factors

BACKGROUND

Liver steatosis (LS) and chronic infection with hepatitis B virus (HBV) are two common causes of chronic liver disease in Iran. LS is also a common histopathological feature of chronic hepatitis B (CHB). Association of chronic HBV infection and LS has not been extensively studied.

AIM

We investigated the prevalence of histological evidence of LS in a group of patients with chronic HBV infection undergoing liver biopsy and compared clinical data, laboratory features, and severity of hepatic fibrosis between patients both with and without steatosis.

METHODS

A total of 132 patients with CHB, undergoing liver biopsy for diagnostic purposes over a 2-year period were enrolled in this study. Clinical, biochemical, and histological factors that might have any kind of association with the presence of steatosis were evaluated.

RESULTS

Of the 132 patients with a liver biopsy, steatosis was present in 56 (42.4%) of the patients, of whom 36 (64%) had grade 1, 14 (25%) grade 2, and six (10.7%) grade 3. Our data showed that LS is not associated with age, sex, HBeAg, viral load, amount of fibrosis, serum cholesterol level, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase. Although body mass index, serum triglyceride, fasting blood glucose, and gamma-glutamyl transpeptidase showed significant correlation with LS in univariate analysis, in multivariate analysis only the serum triglyceride level was significantly correlated with LS.

CONCLUSION

Steatosis is a relatively common finding in CHB and metabolic host factors rather than viral factors responsible for the presence of steatosis in these patients.

Hepatic steatosis has no impact on the outcome of treatment in patients with chronic hepatitis B infection

BACKGROUND

Hepatic steatosis, as a predictive factor in treatment outcome, was not investigated in chronic hepatitis B (CHB). The aim of this retrospective analysis is to determine possible relationships between hepatic steatosis and treatment response in patients with CHB.

METHODS

One hundred forty patients with CHB [42 hepatitis B e antigen (HBeAg)-positive, 98 HBeAg-negative] were analyzed. Seventy-eight patients (55.7%) received pegylated interferon alpha 2a 180 mug/wk subcutaneously and 62 patients (44.3%) received pegylated interferon alpha 2a 180 mug/wk plus lamivudine 100 mg/d combination therapy.

RESULTS

The presence of steatosis was associated with increased body mass index and hyperlipidemia. The sustained virologic response (SVR) rates in HBeAg-negative patients were 36.2% and 31.5% in patients with and without steatosis, respectively (P>0.05). The SVR rates in HBeAg-positive patients were 39.6% and 33.3% in patients with and without steatosis, respectively (P>0.05). The prevalence of hepatic steatosis did not significantly affect the outcome of treatments in both groups. In pegylated interferon monotherapy group (group 1), SVR was 18/78 (23%) and in the pegylated interferon plus lamivudine combination group (group 2) SVR was 16/62 (26%), (P>0.05, NS). The independent factors affecting the treatment outcome were higher baseline alanine aminotransferase level and lower baseline viral load.

CONCLUSIONS

The prevalence of steatosis is a common finding in CHB infection; however, it is not associated with viral load and treatment outcome.