Clinical and serological variation between patients infected with different Hepatitis B virus genotypes

Resistant mutations within the hepatitis B virus reverse transcriptase sequence in treatment failure patients with chronic HBV infection in Vietnam

OBJECTIVES

We conducted this study to describe whether mutations in the gene coding for the enzyme reverse transcriptase (RT) were related to drugs used in the treatment of hepatitis B in Vietnam.

METHODS

Patients receiving antiretroviral therapy with evidence of treatment failure were included in the study. The RT fragment was cloned using the polymerase chain reaction technique after being extracted from patients' blood samples. The nucleotide sequences were analysed using Sanger method. The HBV drug resistance database contains mutations associated to resistance to existing HBV therapies. Medical records were accessed to collect information on patient parameters, such as treatment, viral load, biochemistry, and blood count.

RESULTS

Resistance mutations to lamivudine, telbivudine, and entecavir were found in the highest proportion (75-91.7%) of HBV samples from patients who had failed antiretroviral therapy. Only 20.8% of HBV strains had mutations exhibiting adefovir resistance, while none had mutations conferring tenofovir resistance. M204I/V, L180M, and L80I are frequent variants linked with resistance to lamivudine, telbivudine, and entecavir. In contrast, the A181L/T/V mutation was detected predominantly in tenofovir-resistant HBV strains. Following the drug resistance mutation test, patients achieved the greatest virological response after 24 weeks of therapy with tenofovir and entecavir at a daily dose of one tablet.

CONCLUSION

Lamivudine, telbivudine, and entecavir were all highly resistant to the RT enzyme modifications in 24 treatment failure patients, with M204I/V, L180M, and L80I being the most prevalent mutations. Tenofovir resistance mutations have not been found in Vietnam.

Biological features of hepatitis B virus strains associated with fulminant hepatitis

Accumulating evidence suggests that hepatitis B virus (HBV) biological features may influence the course and clinical manifestations of infection and possibly the development of fulminant hepatitis (FH). Since HBV is not a cytocidal virus, virus-induced liver damage results from an interplay between the virus replication and the host's defense. Therefore, viral factors contributing to enhanced replication, induction of a stronger immune attack or apoptosis of hepatocytes could be crucial in development of FH. Numerous mutations in basal core promoter, pre-C, C and S regions of the HBV genome contribute to development of FH by different mechanisms, including enhanced viral replication, the loss of a decoy for immune response, unbalanced expression of viral proteins and retention of unprocessed cytotoxic proteins in hepatocytes.

Prevalence of Hepatitis B Virus, Genotypes, and Mutants in HBsAg-Positive Patients in Meerut, India

Background

Genetic changeability of hepatitis B virus (HBV) signifies a challenge for the sensitivity of immunologic and molecular diagnostics. Therefore, knowing the spread of HBV genotypes (GENs) and mutation has considerable impacts on treatment strategies, vaccination program, diagnosis, and prevention. The present study aimed to detect HBV GENs and mutants in HBsAg-positive patients.

Methods

The study conducted on 4927 patients in Meerut, India, between March 2013 and April 2017. The blood specimens were analyzed for HBsAg using an ELISA kit, then the blood samples from HBsAg-positive patients were subjected to HBeAg assay and DNA isolation. Amplification of the HBV DNA of pre-S gene and pre-core or basal core promoter region were performed by RT-PCR and sequenced to analyze both GEN and mutation.

Results

According to the results, 245 cases were positive for HBsAg, and 55 were HBeAg-positive. With regard to HBV DNA levels, 16 samples were found positive in PCR assay with 7 (43.8%) less than 2000 IU/mL, 4 (25%) between >2000 and 20,000 IU/mL, and 5 (3.25%) >20,000 IU/mL. No mutations were detected in GENs B and A. The prevalence of HBV GENs B and A were 68.8% (n = 11) and 31.25% (n = 6), respectively.

Conclusion

GEN-B was more prevalent in comparison to GEN-A. The genetic diversity of HBV and distribution of its GENs and mutation improve the current knowledge of epidemiological, clinical and virological patterns of hepatitis B in this region, which help physicians to prescribe proper antiviral/interferon therapy according to current genotyping pattern.

Potential resistant mutations within HBV reverse transcriptase sequences in nucleos(t)ide analogues-experienced patients with hepatitis B virus infection

This study was performed to analyze the potential resistant mutations within HBV reverse transcriptase (RT) sequences against nucleos(t)ide analogues (NA). HBV DNA RT region spanning from amino acid 169 to 250 was amplified and sequenced from 435 HBV patients who experienced NA treatment. Among study’s cohort, genotypes B and C infected patients were 55.9% and 44.1%, respectively. Mutations were recorded in 54.7% (238/435) patients at 22 positions. Genotype C displayed significant higher frequency of potential NA resistant mutations than genotype B (63.0% vs. 48.1%, P = 0.003). Moreover, eight mutation sites, including 180, 181, 191, 200, 202, 221, 229 and 224, in genotype C showed significant higher frequencies than in genotype B. In contrast, mutation at site 236 was more common in genotype B. Notably, 11 mutations at position 169, 202, 250, 173, 180, 200, 207, 214, 237, 242 and 245 coexisted with M204I or V. Substitutions at nine non-classical mutation sites (191, 207, 213, 218, 221, 224, 229, 238 and 242) were detected in patients with virological breakthrough. Particularly, tenofovir (TDF) resistance was observed in one patient undergoing TDF monotherapy and experienced several NA treatment before. These results might provide clinical useful information under antiviral therapy.

Hepatitis B virus in Mar del Plata, Argentina: Genomic characterization and evolutionary analysis of subgenotype F1b

The aim is to describe the molecular epidemiology and perform a genomic characterization of hepatitis B virus (HBV) circulating in Mar del Plata and to identify the origin and diversification patterns of the most prevalent genotype. The S gene and the region encompassing the X gene, basal core promoter (BCP), and precore (preC) was analyzed in 56 samples. They were genotyped as: 80% F1b, 9% A2, 7% D3, and 2% D1. A recombinant F4/D2 genome was detected. The double substitution G1764A/A1762T at the BCP (reduced HBeAg expression) was found in 20% F1b, 2% A2, 2% D1, and 2% D3 samples. A unique D3 presented the G1896A substitution at the preC (HBeAg negative phenotype). A 13% of the samples showed mutations at the HBsAg "a" immunodeterminant (escape from neutralizing antibodies). Mutations at the polymerase (antiviral resistance) were found in 52% of the samples. Coalescent analysis of subgenotype F1b, the most prevalent in the city, showed that viral diversification in Mar del Plata started by year 2000. F1b was the most prevalent genotype detected, being a characteristic of actual HBV infections in Mar del Plata. Local HBV exhibit clinically relevant mutations, but a minority of them was shown to be associated to potential vaccination escape or antiviral resistance. Nevertheless, further studies are needed to determine whether any of these mutants could pose a threat to prevention, diagnosis, or treatment.

Hepatitis B virus genotypes and mutations in the basal core promoter and pre-core/core in chronically infected patients in southern Brazil: a cross-sectional study of HBV genotypes and mutations in chronic carriers

INTRODUCTION

In Brazil, little data exist regarding the distribution of genotypes in relation to basal core promoter (BCP) and precore/core mutations among chronic hepatitis B virus (HBV) carriers from different regions of the country. The aim of this study was to identify HBV genotypes and the frequency of mutations at the BCP and precore/core region among the prevalent genotypes in chronic carriers from southern Brazil.

METHODS

Nested-polymerase chain reaction (nested-PCR) products amplified from the S-polymerase gene, BCP and precore/core region from 54 samples were sequenced and analyzed.

RESULTS

Phylogenetic analysis of the S-polymerase gene sequences showed that 66.7% (36/54) of the patients were infected with genotype D (D1, D2, D3), 25.9% (14/54) with genotype A (A1, A2), 5.6% (3/54) with subgenotype C2, and 2% (1/54) with genotype E. A comparison of virological characteristics showed significant differences between genotypes A, C and D. The comparison between HBeAg status and the G1896A stop codon mutation in patients with genotype D revealed a relationship between HBV G1896A precore mutants and genotype D and hepatitis B e antigen (HBeAg) seroconversion. Genotype D had a higher prevalence of the G1896A mutation and the presence of a thymine at position 1858. Genotype A was associated with a higher prevalence of the G1862T mutation and the presence of a cytosine at position 1858.

CONCLUSIONS

HBV genotype D (D3) is predominant in HBV chronic carriers from southern Brazil. The presence of mutations in the BCP and precore/core region was correlated with the HBV genotype and HBeAg negative status.

Genetic variability of hepatitis B virus in Uruguay: D/F, A/F genotype recombinants

Hepatitis B virus (HBV) infection is a serious global health problem. Approximately 2 billion people worldwide have been infected, and approximately 350 million individuals currently suffer from HBV-induced chronic liver infection, which causes 600,000 deaths annually from chronic hepatitis, cirrhosis and hepatocellular carcinoma. HBV is classified in eight genotypes (A-H), and two more have been proposed (I-J). In this paper, complete genome sequences of nine Uruguayan HBV are reported. Five samples belong to genotype F1b and one to genotype A2. Three HBV recombinants were detected: A1/F1b, A2/F1b and D3/F1b. The following mutations were detected: a G1896A substitution, a 33-nucleotide deletion from position 2896 to 2928 in the Pre-S1 region involving Pre-S1 residues 3-13, a 33-nt deletion in the Pre-S1 region involving nt 2913-2945 and Pre-S1 residues 9-19. More F genotypes strains than expected were detected in this study, supporting the hypothesis that there are more people of indigenous origin than declared in our population. Also, one third of the samples analyzed were recombinants. This cannot be explained by the low HBV prevalence in Uruguay, but a high HBV infection rate in drug addicts and dialysis patients could act in favor of multiple-genotype HBV infections that could lead to recombination.

Molecular identification of hepatitis B virus genotypes/subgenotypes: revised classification hurdles and updated resolutions

The clinical course of infections with the hepatitis B virus (HBV) substantially varies between individuals, as a consequence of a complex interplay between viral, host, environmental and other factors. Due to the high genetic variability of HBV, the virus can be categorized into different HBV genotypes and subgenotypes, which considerably differ with respect to geographical distribution, transmission routes, disease progression, responses to antiviral therapy or vaccination, and clinical outcome measures such as cirrhosis or hepatocellular carcinoma. However, HBV (sub)genotyping has caused some controversies in the past due to misclassifications and incorrect interpretations of different genotyping methods. Thus, an accurate, holistic and dynamic classification system is essential. In this review article, we aimed at highlighting potential pitfalls in genetic and phylogenetic analyses of HBV and suggest novel terms for HBV classification. Analyzing full-length genome sequences when classifying genotypes and subgenotypes is the foremost prerequisite of this classification system. Careful attention must be paid to all aspects of phylogenetic analysis, such as bootstrapping values and meeting the necessary thresholds for (sub)genotyping. Quasi-subgenotype refers to subgenotypes that were incorrectly suggested to be novel. As many of these strains were misclassified due to genetic differences resulting from recombination, we propose the term "recombino-subgenotype". Moreover, immigration is an important confounding facet of global HBV distribution and substantially changes the geographic pattern of HBV (sub)genotypes. We therefore suggest the term "immigro-subgenotype" to distinguish exotic (sub)genotypes from native ones. We are strongly convinced that applying these two proposed terms in HBV classification will help harmonize this rapidly progressing field and allow for improved prophylaxis, diagnosis and treatment.

Variability in the precore and core promoter region of the hepatitis B virus genome

There is increasing evidence that hepatitis B virus (HBV) infections with different genotypes and subgenotypes differ in response to treatment and long-term prognosis. The differences emerge from variability within the genomes that leads to structural deviations at the pregenomic level and to changes at the translational level. Naturally occurring HBV strains covering the four major genotypes A-D were obtained from 393 patients and part of the genome was amplified using polymerase chain reaction (PCR), sequenced, and analyzed for mutational differences in the precore and core promoter regions. The study confirmed that core promoter and precore mutations occur at key positions (A1762T, G1764A, G1896A, and G1899A), and that the proportions of strains with seroconvertion in patients differ between the four HBV genotypes. A rare double mutation (C1857T together with G1897A) was observed, and C1856T was found together with the emerging G1898A mutation, which itself was found to be more widespread geographically than previously described. We found a novel mutation (T1850C), never before observed in human HBV strains but known from woodchuck hepatitis virus (WHV). A novel association of mutation C1773T with G1764T, C1766A, and G1757A was also found within a site already suggested to be a putative binding site for HNF-3. This novel association is proposed by us to be of importance for additional binding of HNH-2 to this site and is a better indicator of the emergence of the double mutation G1764T and C1766A than the G1757A mutation proposed previously.

Influencing Factors on the Outcome and Prognosis of Patients With HBV Infction: Seven Years Follow-up

BACKGROUND

Hepatitis B virus (HBV) is one of the most common chronic viral infections in the world. Iran has a low to intermediate HBV prevalence and approximately 1.5 million people are living with HBV infection. The impact of HBV in Iran is unknown and given the very low levels of alcohol consumption, this region provides an opportunity to examine the impact of isolated chronic HBV infection.

OBJECTIVES

To examine and evaluate outcome and prognosis of HBV in Iran.

PATIENTS AND METHODS

A longitudinal cohort study dating from 2003-2010 was performed. The patients were assessed six months after their first visit and then during periodic visits for the subsequent seven years. The patients' medical history, route of diagnosis of infection, family history, and liver diseases status including: carrier state of HBV, chronic HBV, cirrhosis, and HCC were recorded. Descriptive and analytic statistics were performed, using SPSS software version 18.

RESULTS

275 HBsAg positive patients, who had completed a 7 year follow up period, were selected. The annual incidence rate for chronic hepatitis B in inactive carrier states and cirrhosis were 0.46% and 0.2% respectively. Over seven years, the rate of inactive carriers decreased by eight percent (They turned into chronic HBV or became HBSAg negative). No significant association was found between HBSAg seroclearance, HBeAg seroconversion and the outcome in the end of each year of follow up. Different treatment regimens did not have any statistically significant difference regarding HBeAg seroconversion. There was no significant association between the outcome and different habitual characteristics, especially smoking, as well as family history on HBsAg, HBsAb, HBeAg, and Anti-HBeAg. Values of platelets and ALT showed a significant change during the follow ups. Annual incidence rate of HCC in the present study was in the range of other studies.

CONCLUSIONS

These data confirm and extend data from other populations showing a low incidence of significant change in chronic HBV infection in short term with good responses to currently available therapeutics.

Frequency and clinical significance of core promoter and precore region mutations in Tunisian patients infected chronically with hepatitis B

Genetic variability of hepatitis B virus (HBV) in the C gene and its association with the different stages of chronic liver disease has been studied inadequately with controversial results. The objectives of the current study were to determine the frequency of core promoter and precore mutations in chronic hepatitis B in Tunisia and to evaluate their impact on viral replication and disease progression. Sequencing was performed in upstream regulatory sequence (URS), pre-core (PreC) and basal core promoter (BCP) regions for 123 chronic infected patients by HBV genotype D at different status of disease. Mutations were detected in 98.4% of cases, affecting URS, BCP and Pre-C in 95.1%, 95.9% and 87.8% respectively. Multi-mutations increased significantly from asymptomatic carrier to advanced liver disease status. G1896A (74.8%), G1764A/T/C (71.5%), G1899A (54.4%) and T1678C (52%) were the most common. Special attention should be paid to A1703T, T1678C/G-A1703T, and A1652G-A1679G mutations probably specific of Tunisians sequences; they were observed in 40.6%, 41.5% and 30.1% respectively. A1679G/C, T1753C/G/A, A1762T/G and A1762T-G1764A were more prevalent in older patients. High DNA levels were associated with G1899A or G1764T/C-C1766G-C1799G and advanced liver disease with mutations at positions 1762, 1764 and/or 1899 alone or in double or triple mutations. It was also shown that substitutions at nucleotides 1762, 1764 and 1899 have an impact on the disease progression. It is the first report for specific mutations in the URS region for genotype D. It should be completed by studying eventual correlation with clinical progression and the response to treatment.

Atypical serological profiles in hepatitis B virus infection

During hepatitis B virus (HBV) infection, at least four antigen-antibody systems are observed: HBsAg and anti-HBs; preS antigen and anti-preS antibody; HBcAg and anti-HBc; and HBeAg and anti-HBe. Through the examination of these antigen-antibody systems, hepatitis B infection is diagnosed and the course of the disorder may be observed. Although the serologic findings that allow both the diagnosis of HBV infection as well as assessing of its clinical course are already well established, the dynamics of viral proteins expression and of the antibodies production may vary during the infection natural course. This causes the HBV infection to be occasionally associated with the presence of uncommon serological profiles, which could lead to doubts in the interpretation of results or suspicion of a serological result being incorrect. This paper is dedicated to the discussion of some of these profiles and their significance.

Molecular characterization of hepatitis B virus X gene in chronic hepatitis B patients

Background

HBV-X protein is associated with the pathogenesis of HBV related diseases, specially in hepatocellular carcinomas of chronic patients. Genetic variability of the X gene includes genotypic specific variations and mutations emerging during chronic infection. Its coding sequence overlaps important regions for virus replication, including the basal core promoter. Differences in the X gene may have implications in biological functions of the protein and thus, affect the evolution of the disease. There are controversial results about the consequences of mutations in this region and their relationship with pathogenesis. The purpose of this work was to describe the diversity of HBV-X gene in chronic hepatitis patients infected with different genotypes, according to liver disease.

Methods

HBV-X gene was sequenced from chronic hepatitis B patient samples, analyzed by phylogeny and genotyped. Nucleotide and aminoacid diversity was determined calculating intragenetic distances. Mutations at 127, 130 and 131 aminoacids were considered in relation to liver disease.

Results

The most prevalent genotype detected in this cohort was F (F1 and F4), followed by D and A. Most of the samples corresponding to genotypes A and F1 were HBeAg(+) and for genotypes D and F4, HBeAg(−) samples were represented in a higher percentage. Intragenetic distance values were higher in HBeAg(−) than in positive samples for all genotypes, and lower in overlapped regions, compared to single codification ones. Nucleotide and aminoacid diversities were higher in HBeAg(−), than in HBeAg(+) samples.

Conclusions

Independently of the infecting genotypes, mutations at any of 127, 130 and/or 131 aminoacid positions and HBeAg(−) status were associated with mild liver disease in this cohort.

Hepatitis B virus gene mutations in liver diseases: a report from New Delhi

OBJECTIVES

The study was designed to characterize the surface, core promoter, precore/core region sequences for the presence of mutations in hepatitis B virus (HBV) associated with different liver diseases.

METHODS

567 HBV associated patients with different liver diseases were enrolled in this study. All samples were analyzed for HBV surface, core promoter, precore/core region mutations and genotypes using PCR and direct sequencing.

RESULTS

HBV genotype D (72.8%) was the predominant type followed by genotype A (27.2%). The serum viral load of HBV was highest in HBsAg carriers group and lowest in patients with hepatocellular carcinoma. 17.9% patients with cirrhosis and 24.6% hepatocellular carcinoma cases were ADV-resistant with rtA181T/V mutations in the S-gene. A1896T was found more frequently in fulminant hepatic failure compared to acute viral hepatitis patients (p = 0.038). T1753V mutation was significantly higher in patients with cirrhosis of liver (34.6%) than in chronic hepatitis (18.9%) and hepatocellular carcinoma patients (21.2%; p = 0.001). T1762/A1764 mutation was observed in all the groups. C1914G core gene mutation was associated with the hepatocellular carcinoma (32.2%) compared to other groups. HBV genotype D predominated in comparison to genotype A. An increased frequency of precore mutation and BCP double mutations amongst the population studied was also observed.

CONCLUSION

Mutations such as T1762/A1764, T1753V and C1914G were usually associated with advanced forms of liver disease and had an increased risk of HCC. The nucleotide variability in the basal core promoter and precore regions possibly plays a role in the progression of HBV disease. Prospective studies on the sequence variations of the preC/C region of the HBV genome and the molecular mechanisms in relation to progression of liver disease would aid in better understanding of the biological significance of HBV strains in India.

The relationship between core promoter mutation of hepatitis B virus, viral load and hepatitis B e antigen status in chronic hepatitis B patients

The aim of this study is to detect the possible association of hepatitis B virus (HBV) core mutation, hepatitis B e antigen (HBeAg) status and the viral load in chronic hepatitis B (CHB) patients. Sixty-six patients with CHB were enrolled. Hepatitis markers and hepatitis C virus antibody (HCV-Ab) were tested using micro particle enzyme immunoassay kits. Viral load was measured by real-time polymerase chain reaction (PCR) and the mutation was analyzed by nested PCR followed by restriction fragment length polymorphism. Most of CHB patients were HBeAg (-ve). The HBeAg status did not have an influence on the presence or absence of T1762/A1764 mutation. HBV-DNA serum level was not significantly different in patients with core mutation and patients without core mutation in HBeAg (-ve) group, while in HBeAg (+ve) group HBV-DNA serum level was significantly higher in patients with core mutation. This study reports the predominance of HBeAg (-ve) and HBV core promoter mutation.

Hepatitis B virus S gene escape mutants

Hepatitis B virus (HBV) can be classified into nine immunological subtypes or eight genotypes. The most prevalent genotypes in Asia are genotypes B and C. HBV is transmitted parenteraly and can produce either asymptomatic or symptomatic disease. Although the consequences of acute hepatitis B can be severe, serious sequelae are associated with chronic infections. HBV seroprevalence ranges from intermediate (2%-7%) to high (≥8%) levels in Asia. Several strategies for the control and prevention of HBV infection have been found to be efficacious. They include vaccination and the administration of HBIG, interferon-a and nucleoside/nucleotide analogues. However, these procedures also apply selective pressures on HBV in infected individuals leading to the generation and accumulation of mutations in the S gene. Most of these mutations occur in the major hydrophilic region (MHR) of the S gene. These mutations create public health concerns as they can be responsible for reactivation of hepatitis B and occult hepatitis B infection. The inability to detect occult infections means that these individuals may become blood donors. This suggests that new strategies for donor evaluation and selection may need to be developed to protect the blood supply.

Quantitative assessment of the antiviral potencies of 21 shRNA vectors targeting conserved, including structured, hepatitis B virus sites

BACKGROUND & AIMS

RNA interference (RNAi) may offer new treatment options for chronic hepatitis B. Replicating via an RNA intermediate, hepatitis B virus (HBV) is known to be principally vulnerable to RNAi. However, beyond delivery, the relevant issues of potential off-target effects, target site conservation in circulating HBV strains, and efficacy of RNAi itself have not systematically been addressed, nor can the different existing data be quantitatively compared. The aim of this study was to provide such information.

METHODS

To focus on the intracellular RNAi process itself and minimise other variables affecting overall RNAi efficacy, we used a robust co-transfection system to quantitatively assess the relative potencies of 21 small-hairpin (sh) RNA vectors, targeting conserved sites throughout the HBV genome, against viral RNAs, proteins, nucleocapsids, and secreted virions under standardised conditions.

RESULTS

The approach enabled a distinct efficacy ranking, with the six most potent shRNAs achieving 95% reductions in virion formation, sequence-specifically and without detectable interferon induction, yet by differentially affecting different steps. Efficacy correlated poorly with predictions and was not principally abolished by target structure. Sequence comparisons suggest that truly conserved, RNAi-targetable sequences comprise less than 500 nucleotides of the circulating HBV genomes.

CONCLUSIONS

The HBV genome can harbour only a finite number of optimal target sites, but current predictions are poorly suited to constrain the number of possible candidates. However, the small size of the highly conserved sequence space suggests experimental identification as a viable option.

Relationship between distribution of HBV genotypes and liver diseases in Lhasa

AIM: To study the distribution of HBV genotypes and the clinical relevance of genotype with hepatitis B in Lhasa, Tibet Autonomous Region of China.

METHODS: Ninety two HBV-infected cases were analyzed for genotypes using gene chip technology. And association between its epidemiology, DNA content, liver function, gender and ethnicity was investigated.

RESULTS: Seventy-three HBV DNA positive cases with varying genotypes showed significant differences (χ² = 7.179, P < 0.05). Among HBV DNA positive samples, there were 32 cases of e antigen positive, and no significant difference was observed in the DNA content but significant difference was detected in the national e antigen positive rate (χ² = 8.423, P < 0.05). Genotypes B and C were mostly present in the Han nationality, while D-type existed mainly in Tibetan. ALB was lower in type D,C than in B, but GLB was higher in B. CHB and LC were mainly present in patients D and C genotypes (F = 3.832, P < 0.05).

CONCLUSION: The HBV genotype DNA load shows no difference and no significant association between liver function enzymes and disease conditions, and protein changes are more notable. Patients with C or D genotype are more vulnerable to disease progression than those with B genotype in Lhasa, Tibet region.

Clinical, virologic and phylogenetic features of hepatitis B infection in Iranian patients

AIM: To characterize the clinical, serologic and virologic features of hepatitis B virus (HBV) infection in Iranian patients with different stages of liver disease.

METHODS: Sixty two patients comprising of 12 inactive carriers, 30 chronic hepatitis patients, 13 patients with liver cirrhosis and 7 patients with hepatocellular carcinoma (HCC) were enrolled in the study. The HBV S, C and basal core promoter (BCP) regions were amplified and sequenced, and the clinical, serologic, phylogenetic and virologic characteristics were investigated.

RESULTS: The study group consisted of 16 HBeAg-positive and 46 HBeAg-negative patients. Anti-HBe-positive patients were older and had higher levels of ALT, ASL and bilirubin compared to HBeAg-positive patients. Phylogenetic analysis revealed that all patients were infected with genotype D (mostly ayw2). The G1896A precore (PC) mutant was detected in 58.1% patients. HBeAg-negative patients showed a higher rate of PC mutant compared to HBeAg-positive patients (χ² = 9.682, P = 0.003). The majority of patients with HCC were HBeAg-negative and were infected with PC mutant variants. There was no significant difference in the occurrence of BCP mutation between the two groups, while the rate of BCP plus PC mutants was higher in HBeAg-negative patients (χ² = 4.308, P = 0.04). In the HBV S region, the genetic variability was low, and the marked substitution was P120T/S, with a rate of 9.7% (n = 6).

CONCLUSION: In conclusion, HBV/D is the predominant genotype in Iran, and the nucleotide variability in the BCP and PC regions may play a role in HBV disease outcome in HBeAg-negative patients.

Hepatitis B virus genotypes in southwest Iran: Molecular, serological and clinical outcomes

AIM: To investigate the associations of hepatitis B virus (HBV) genotype with HBeAg and anti-HBe status, alanine aminotransferase (ALT) levels and HBV-DNA detection in different groups of HBV-infected patients in southwest Iran.

METHODS: A total of 89 HBsAg-positive serum samples were collected from the same number of patients. All sera were then investigated to determine HBV DNA and serological markers. For all the polymerase chain reaction (PCR)-positive samples, biochemical, histopathological assays and genotyping were also performed.

RESULTS: Genotype D was the only type of HBV found in different clinical forms of acute and chronic infections. There was a high prevalence of HBeAg-negative HBV-infected patients with chronic hepatitis (52.7%). Out of 55 patients with chronic hepatitis, seven (12.7%) were diagnosed with cirrhosis. A significant association between the presence of anti-HBe antibody and an increase in ALT level, among either HBeAg-negative (P = 0.01) or HBeAg-positive (P = 0.026) patients, was demonstrated. No significant differences were observed between the clinical outcomes of HBeAg-positive and -negative individuals (P = 0.24).

CONCLUSION: Genotype D has been recognized as the only type of HBV found in different clinical forms of HBV infections, including cirrhosis, among the residents of southwest Iran. Anti-HBe possibly plays a role in disease progression in some patients with chronic hepatitis, at least for a period of disease.

HBVRegDB: annotation, comparison, detection and visualization of regulatory elements in hepatitis B virus sequences

BACKGROUND

The many Hepadnaviridae sequences available have widely varied functional annotation. The genomes are very compact (approximately 3.2 kb) but contain multiple layers of functional regulatory elements in addition to coding regions. Key regions are subject to purifying selection, as mutations in these regions will produce non-functional viruses.

RESULTS

These genomic sequences have been organized into a structured database to facilitate research at the molecular level. HBVRegDB is a comparative genomic analysis tool with an integrated underlying sequence database. The database contains genomic sequence data from representative viruses. In addition to INSDC and RefSeq annotation, HBVRegDB also contains expert and systematically calculated annotations (e.g. promoters) and comparative genome analysis results (e.g. blastn, tblastx). It also contains analyses based on curated HBV alignments. Information about conserved regions - including primary conservation (e.g. CDS-Plotcon) and RNA secondary structure predictions (e.g. Alidot) - is integrated into the database. A large amount of data is graphically presented using the GBrowse (Generic Genome Browser) adapted for analysis of viral genomes. Flexible query access is provided based on any annotated genomic feature. Novel regulatory motifs can be found by analysing the annotated sequences.

CONCLUSION

HBVRegDB serves as a knowledge database and as a comparative genomic analysis tool for molecular biologists investigating HBV. It is publicly available and complementary to other viral and HBV focused datasets and tools http://hbvregdb.otago.ac.nz. The availability of multiple and highly annotated sequences of viral genomes in one database combined with comparative analysis tools facilitates detection of novel genomic elements.

Variations in the core promoter/pre-core region in HBV genotype C in Japanese and Northern Vietnamese patients

Hepatitis B virus (HBV) subgenotypes Cs (C1) and Ce (C2) are common in East Asia. To investigate the genomic difference of HBV genotype C between two separated regions, 50 subgenotype Cs-infected Vietnamese and 70 subgenotype Ce-infected Japanese patients were enrolled for analysis. The patients were categorized to either a hepatocellular carcinoma group (HCC) or a non-HCC group including liver cirrhosis, chronic hepatitis, and asymptomatic carriers. HBV serology, HBV-DNA level, and variations in core promoter/pre-core region were examined. Phylogenetic analysis based on the full genome sequences and nucleotide sequences partly in the S gene and in the P gene revealed that all Japanese strains (70/70) were subgenotype Ce, and nearly all of the Vietnamese strains (50/51) were subgenotype Cs, excluding one subgenotype C5. C1858 and G1775 were common in the Vietnamese (64% and 40%) but not in the Japanese (0%). The prevalence of C/A1753 in Vietnamese was higher than that in the Japanese (32% vs. 17.1%), however the frequency of A1896 in the Japanese was significantly higher (32.9% vs. 12%, P < 0.05). Most of the Vietnamese patients with HCC had a high level of HBV-DNA, the Japanese HCC had a relatively low level. In the Vietnamese, C/A1753 and C1858 were associated closely with T1762A1764, higher HBV-DNA levels and higher HCC incidence. The multivariate analysis revealed that male, T1653 and C/A1753 were independent risk factors for HCC. The subgenotypes and unique mutations of HBV genotype C in the Vietnamese and Japanese differed, and C/A1753 and C1858 variants might play a role in the pathogenesis of liver disease in Vietnamese patients.

Influence of hepatitis B virus X and core promoter mutations on hepatocellular carcinoma among patients infected with subgenotype C2

Hepatitis B virus (HBV) genotypes/subgenotypes and their related mutations in the HBV genome have been reported to be associated with hepatocellular carcinoma (HCC). To determine the HCC-associated mutations of the HBV genome in the entire X, core promoter, and precore/core regions, a cross-sectional control study was conducted comparing 80 Japanese patients infected with HBV C2 and suffering from HCC with 80 age-, sex-, and hepatitis B e antigen (HBeAg) status-matched patients without HCC (non-HCC group). Each HBeAg-positive group (31 with HCC; 29 without HCC) and HBeAg-negative group (49 with HCC; 51 without HCC) was also matched with respect to age and sex. The C1479, T1485, H1499, A1613, T1653, V1753, T1762/A1764, and A1896 mutations were frequent in this population. The prevalences of the T1653 mutation in the box alpha region and the V1753 and T1762/A1764 mutations in the basal core promoter region were significantly higher in the HCC group than in the non-HCC group (56% versus 30%, 50% versus 24%, and 91% versus 73% [P = 0.0013, P = 0.0010, and P = 0.0035, respectively]). The platelet count was significantly lower for the HCC group than for the non-HCC group (10.7 x 10(4) +/- 5.1 x 10(4) versus 17.3 x 10(4) +/- 5.1 x 10(4) platelets/mm(3) [P < 0.0001]). Regardless of HBeAg status, the prevalence of the T1653 mutation was higher in the HCC group (52% versus 24% [P = 0.036] for HBeAg-positive patients and 59% versus 33% [P = 0.029] for HBeAg-negative patients). In the multivariate analysis, the presence of T1653, the presence of V1753, and a platelet count of < or =10 x 10(4)/mm(3) were independent predictive factors for HCC (odds ratios [95% confidence intervals], 4.37 [1.53 to 12.48], 7.98 [2.54 to 25.10], and 24.39 [8.11 to 73.33], respectively). Regardless of HBeAg status, the T1653 mutation increases the risk of HCC in Japanese patients with HBV/C2.

Molecular epidemiological study of hepatitis B virus infection in two different ethnic populations from the Solomon Islands

The Solomon Islands is a multi-ethnic nation with a high rate of hepatitis B virus (HBV) infection. The prevalence relative to ethnicity was examined in relation to HBV infection, genotypes, and mutations. Asymptomatic populations (n = 564, 308 Melanesian and 118 Micronesian) from the Western Province were enrolled. Positive samples for Hepatitis B surface antigen (HBsAg) were examined for serological status, genotyping, viral load, and mutations of the basic core promoter (BCP) and pre-core (Pre-C) regions. The positive rate for HBsAg was 21.5%. The major Melanesian genotype was C (HBV/C), whereas the major Micronesian genotype was D (HBV/D). The prevalence of Hepatitis B e antigen (HBeAg) in serum was lower in carriers of HBV/D than of HBV/C. While the prevalence of the BCP mutation (T(1762)A(1764)) tended to be higher in HBV/C, that of the Pre-C mutation (T(1846)) was significantly higher in HBV/D (P < 0.0001). Genetic distance and phylogenetic analyses based on complete genome sequences were also carried out for two strains of HBV/C and two strains of HBV/D, and the findings were compared with those in the DDBJ/EMBL/GenBank database. The full-length sequence revealed that strains from the Solomon Islands were classified into subgenotype C3 (HBV/C3) and D4 (HBV/D4), and that the HBV/D strains were related closely to those from Papua New Guinea. HBV infection in the Solomon Islands is hyperendemic, and the genotype is ethnicity-specific. HBeAg appears to clear from the serum in young adulthood in HBV/D infection, which may be influenced by genotype-dependent features in relation to viral mutations.

Hepatitis B virus (HBV) genotypes in Egyptian pediatric cancer patients with acute and chronic active HBV infection

Background

There are eight genotypes of hepatitis B virus (A-H) and subgenotypes are recognized. Genotyping can be accomplished based on a partial sequence of HBV genome such as the pre-S or S gene. Several methods have been developed and used for HBV genotyping. This study was undertaken to determine the HBV genotypes in Egyptian pediatric cancer patients with acute and chronic liver disease.

Methods

HBV genotypes were determined in 22 patients who had acute forms of liver disease (AH) and in 48 patients with chronic active hepatitis (CAH). A type-specific primer based the nested-PCR method was employed in the HBV genotyping.

Results

This study showed that HBV infections in pediatric cancer patients are attributed predominantly to viral genotypes D and B that constituted 37.1% and 25.7%, respectively of the total infections. In addition, there was a relatively high prevalence of mixed infections of 15.7% among the studied group especially mixed A/D genotype infections. Genotype D was found significantly more often in patients with CAH than in patients with AH [23/48(47.9%) v 3/22 (13.6%)].

Conclusion

These findings show the distribution of HBV A-D genotypes in pediatric cancer Egyptian patients. Furthermore, our results indicate a markedly high prevalence of mixed A/D genotype infections in subjects with CAH and a possible association of mixed infections with the severity of liver diseases.

Hepatitis B virus genotypes in Europe

There are eight genotypes of hepatitis B virus (HBV). Most genotypes can be further divided into subgenotypes. HBV genotypes influence the course of disease and treatment, and show geographic preferences. In Europe, A and D are the main genotypes found. Genotype A is more prevalent in northern Europe, where genotype D is mainly found in countries surrounding the Mediterranean Sea and in Eastern Europe. Subgenotype A2 is the dominant subgenotype in Europe, but the geographic prevalence of the four subgenotypes found in genotype D is not yet clear. On treatment with interferon HBV, genotype A, compared to genotype D, showsbetter virological response and in a large proportion of patients, even development of anti-HBs. However, in the first year of treatment with lamivudine, higher rates of emergence of YMDD variants are observed in genotype A. This work summarizes the current knowledge on HBV genotypes in countries with low and intermediate HBV carriership from Europe.

Clinical implications of HIV and hepatitis B co-infection in Asia and Africa

Hepatitis B virus (HBV) is the leading cause of chronic liver disease and liver-related death worldwide, with the majority of these cases occurring in areas of Africa and Asia where HBV prevalence is high. Many of the countries that are affected by hepatitis B are also affected by a high HIV burden, leading to frequent HIV/HBV co-infection. The consequences of co-infection, including increased liver-related morbidity and mortality, increased hepatitis B viral replication, immune reconstitution to HBV in the setting of antiretroviral therapy, and hepatotoxicity from antiretroviral drugs, are especially important in regions with expanding antiretroviral programmes. Little data, however, are available on HIV/HBV co-infection from regions with high chronic hepatitis B prevalence. This Review discusses the epidemiology, natural history, pathogenesis, and management of HIV/HBV co-infection from these areas. Topics for future research relevant to HIV/HBV co-infection in Africa and Asia are also highlighted.

Hepatitis B virus (HBV) genotypes/subgenotypes in China: mutations in core promoter and precore/core and their clinical implications

BACKGROUND

The association of hepatitis B virus (HBV) genotypes with clinical course of infection is increasingly recognized.

OBJECTIVES

In order to investigate the genetic diversity of HBV and its clinical implications, 241 HBV-infected patients including 34 with hepatocellular carcinoma (HCC) were enrolled in this study.

METHODS

HBV genotyping was performed with an ELISA assay. HBV subgenotypes were determined by PCR-RFLP. HBV core promoter/precore/core mutations were analyzed by direct sequencing.

RESULTS

The overall prevalence of HBV/B and C was 65% and 33%, respectively. Among HBV/C, 42% were Cs/C1 and 58% were Ce/C2. The HBV/C1 was only found in the patients originating from Southern China (p=0.0001). Among HCC patients, HBV/C2 was only found in the elder age group (> or =51 years; p<0.05) and HBV/Ba was associated with young HCC patients (<35 years). Mutations associated with HCC were V1753 and T1762/A1764 (p<0.01). The prevalence of the V1753 was higher in HBV/C1 strains (p<0.04), A1898 was only found among HBV/C1 (p=0.056). T1762/A1764 was frequently demonstrated in both subgenotypes. The T1858 (90%) and A1896 (40%) mutations were most frequent in HBV/C2 (p<0.008).

CONCLUSIONS

HBV/C1 and HBV/C2 have distinct geographic distributions in China. V1753 in addition to T1762/A1764 double mutation in the basal core promoter region seems to be associated with HCC development, especially in the patients with HBV/C1.

Detection and quantification of hepatitis B virus DNA by SYBR green real-time polymerase chain reaction

A single-round real-time polymerase chain reaction (PCR) assay based on SYBR green dye technology for the detection and quantification of hepatitis B virus (HBV) DNA in serum was evaluated and compared with a qualitative nested PCR and the Cobas Amplicor HBV Monitor assay (Roche Molecular Diagnostics, Milan, Italy). The performance of the real-time PCR assay was evaluated in a routine clinical laboratory setting with a total of 212 clinical specimens. The sensitivity of the real-time PCR corresponded to 31 IU/ml (70 copies/ml), and comparison with the qualitative nested PCR showed significant concordance for 94% of samples. The linear curve over 7 log units, spanning 10(3)-10(9) IU/ml (2.28 x 10(3) to 2.28 x 10(9) copies/ml), was observed in the quantitative determination. The interexperimental variability coefficient of the assay ranged from 0.22 to 0.39 and the intraexperimental variability coefficient from 0.24 to 0.41. By excluding values outside of the dynamic ranges of both tests, the HBV Monitor and the real-time PCR gave an agreement within +/-1 log unit for 90% of samples, while those for the remaining 10% were found to be above 1 log unit but less than 1.5 log units. When the results inside and outside the dynamic range of the HBV Monitor were examined, 90% of the results were in agreement. In conclusion, the real-time PCR based on SYBR green technology proved suitable for routine diagnostic purposes, showing good sensitivity, high specificity, high reproducibility, and good linearity over a broad dynamic range of quantification.

Acute hepatitis B virus infection by genotype F despite successful vaccination in an immune-competent German patient

BACKGROUND

Hepatitis B Virus (HBV) infection is a leading cause of chronic hepatitis and liver cirrhosis worldwide, and efficient protection can usually be achieved by vaccination that is based on recombinant HBsAg protein from HBV genotype A and D.

RESULTS

Here we report the case of a fully immune-competent German patient that acquired a symptomatic acute HBV infection during adulthood despite a complete and formally successful vaccination, which had resulted in anti-HBs titers considered protective. Further phylogentic analysis identified an infection with the rare genotype F of HBV, possibly acquired in Spain, without apparent aberrations in the immunodominant 'a' determinant domain of the envelope gene. However, sequence comparisons revealed that all reported genotype F isolates display marked differences from the other genotypes in this domain which serves as an epitope for humoral immune responses.

CONCLUSIONS

The rare HBV genotype F, as detected in this immune-competent, previously vaccinated patient, has marked sequences differences in the envelope/polymerase gene. Therefore, current HBV vaccines based on genotype A and D may not result in full protective immunity towards viral strains from genotype F.

Specific mutations in enhancer II/core promoter of hepatitis B virus subgenotypes C1/C2 increase the risk of hepatocellular carcinoma

BACKGROUND/AIMS

Hepatitis B virus genotype C (HBV/C) has been classified into two geographically distinct subgenotypes; HBV/C1/Cs (Southeast Asia) and HBV/C2/Ce (East Asia).

METHODS

Viral differences in enhancer II/core promoter and precore regions between the subgenotypes and their association with hepatocellular carcinoma (HCC) were assessed in a matched cross-sectional control study of 118 carriers (from Hong Kong) with HBV/C1/Cs (48.0 years, 81% male, 40% HBeAg+, 44% HCC) and 210 HBV/C2/Ce (172 from Japan, 38 from Hong Kong) (50.2 years, 78% male, 30% HBeAg+, 46% HCC).

RESULTS

Univariate analyses showed that mutation V1753 was predictive for HCC among HBeAg-positive-C1/Cs-carriers (P=0.0055), and T1653 among HBeAg-positive-C2/Ce-carriers (P=0.018), and T1653 or V1753 or T1762/A1764 among HBeAg-negative-C2/Ce-carriers (P<0.05). In the multivariate analysis on all HBV/C subjects, independent predictive factors for HCC were subgenotype C2/Ce (odds ratio, 4.21; 95% confidence interval, 1.07-16.23), T1653 (3.64; 1.93-6.86), V1753 (3.07; 1.66-5.65) and T1762/A1764 (2.58; 1.21-5.49) mutations, age (50 years), gender (male) and HBeAg (positive).

CONCLUSIONS

Our data indicate that T1653 and/or V1753 mutations in addition to T1762/A1764 are differently associated with HCC in context of HBeAg status among HBV/C1/Cs and C2/Ce-carriers. HBV/C subgenotypes have specific mutation patterns, which is probably responsible for increased carcinogenesis of HBV/C2/Ce.

Hepatitis B virus genotypes and precore/core-promoter mutations in Tunisian patients with chronic hepatitis B virus infection

OBJECTIVE

The aim of this study was to determine the frequency of genotype and precore/core-promoter mutations in chronic hepatitis B virus (HBV) infected individuals in Tunisia.

METHODS

We studied 164 Tunisian patients (38 HBeAg-positive and 126 HBeAg-negative) with chronic HBV infection. Genotypes and precore/core-promoter mutations were studied using Inno-LiPA and Multiplex-PCR and PCR-RFLP methodology.

RESULTS

Alanine aminotransferase (ALT) levels were higher in HBeAg-positive compared with HBeAg-negative patients (p<0.05). Patients with HBeAg-positive chronic hepatitis B were younger than HBeAg-negative chronic hepatitis B patients. The 164 genotypes were distributed as follows: 1 genotype A (0.6%), 1 genotype B (0.6%), 3 genotype C (1.82%), 139 genotype D (84.75%), and 20 mixed genotypes (12.2%). In the precore region (41.5%) of the patients had exclusively PC mutant and (50.9%) had a mixture of wild-type and variant sequences. PC variant was more commonly found in HBeAg-negative patients than in HBeAg-positive patients (94.5% vs. 87.8%), respectively. The mutations in the core promoter were more common in HBeAg-negative patients (65.4%) than in HbeAg-positive patients (18.2%). These results indicate that genotype D is predominant in Tunisia. Precore mutation occurred invariably among HBeAg-positive and HBeAg-negative patients, whereas core-promoter mutations were more frequently found in HBeAg-negative patients.

CONCLUSION

Analysis of these mutants may prove useful for clinical evaluation and choice of therapy.

Molecular epidemiology of hepatitis B virus in Latin America

Hepatitis B virus (HBV) is an etiological agent of acute and chronic liver disease existing throughout the world. The high genetic variability of HBV is reflected by eight genotypes (A to H), each one with a particular geographical prevalence. The global pattern of HBV genotypes is associated with the distribution of human populations among the different continents and may reflect the patterns of human migrations. Genotypes F and H are considered indigenous to Latin America. The most prevalent genetic group of Central and South America, genotype F, is subdivided into two subtypes and five clusters associated with defined geographic areas. Genotype H has been described in Mexico and Central America. This pattern provides a tool to reconstruct the initial immigration of ancestral Amerindians from Asia and their further spread through Central and South America. Other HBV genotypes found in different Latin American countries may reflect migration from other geographical areas into the region. Genotypes A and D are the signature of the European colonization that started in the sixteenth century, including slave trade from Africa. Genotypes B and C indicate the arrival of people from Southeast Asia. The impact of HBV genotypes on the natural course of HBV infection and response to treatment has been studied recently and controversial results have been obtained. The majority of the current information concerns with genotypes B and C. In contrast, very few data are available on the Latin American HBV genotypes F and H. It has been reported that liver failure and death may be more frequent in patients infected with genotype F. More studies are needed to assess the association between H13V genotypes and clinical course of infection, especially in Latin America.

Hepatitis B virus genotyping, core promoter, and precore/core mutations among Afghan patients infected with hepatitis B: A preliminary report

In spite of hepatitis B virus (HBV) vaccination, HBV infection remains an important public health problem worldwide. Although the HBV genotype distribution has been determined in some parts of South Central Asia, no survey has been conducted to determine the HBV genotype in Afghanistan. Twelve Afghan patients infected with HBV living in Afghanistan were enrolled in this study. Partial HBsAg and basic core promoter, precore, and core (BCP/preC/C) regions were amplified and subjected for direct sequencing. In parallel, precore G1896A mutation was also determined by an amplification-created restriction site method. Results revealed HBV genotype D (95% bootstrap value), sub-genotype D1 (98% bootstrap value), and subtype ayw2 in all Afghan isolates. Afghan isolates clustered in a separate branch in the D1 sub-genotype called D1', while supported by 82% bootstrap value. The percentage of intra-genotypic distance among Afghan isolates was 1.05% and inter-genotypic distance with the other genotype D was 2.87% and with other genotypes was 7.50%-11.1%. The wild-type, mixed infection, and precore mutant were found in six, two, and four HBV isolates, respectively. The A1762T/G1764A BCP dual mutation was found in one isolate. Three isolates presented single mutation in the BCP dual mutation region, whereas two showed a novel G1764T mutation. In conclusion, this preliminary study revealed HBV genotype D, sub-genotype D1, and subtype ayw2 of HBV among hepatitis B infected patients from Afghanistan. Further investigation should be carried out.

Correlations of HBV genotypes, mutations affecting HBeAg expression and HBeAg/ anti-HBe status in HBV carriers

This study was carried out to determine the effects of hepatitis B virus genotypes, core promoter mutations (A1762G1764-->T1762A1764) as well as precore stop codon mutations (TGG-->TAG) on HBeAg expression and HBeAg/ anti-HBe status. Study was also performed on the effects of codon 15 variants (C1858/ T1858) on the predisposition of precore stop codon mutations (TGG-->TAG). A total of 77 sera samples were analyzed. Fifty one samples were successfully genotyped of which the predominant genotype was genotype B (29/ 51, 56.9 %), followed by genotype C (16/ 51, 31.4 %). Co-infections by genotypes B and C were observed in four samples (7.8 %). To a lesser degree, genotypes D and E (2.0 % each) were also observed. For core promoter mutations, the prevalence was 68.8 % (53/ 77) for A1762G1764 wild-type and 14.3 % (11/ 77) for T1762A1764 mutant while 9.1 % (7/ 77) was co-infected by both strains. The prevalence of codon 15 variants was found to be 42.9 % (33/ 77) for T1858 variant and 16.9 % (13/ 77) for C1858 variant. No TAG mutation was found. In our study, no associations were found between genotypes (B and C) and core promoter mutations as well as codon 15 variants. Also no correlation was observed between HBeAg/ anti-HBe status with genotypes (B and C) and core promoter mutations.