HBV core sequence: definition of genotype-specific variability and correlation with geographical origin

Comparative Transcriptional Signature Analysis of Peripheral Blood Mononuclear Cells in Early Stage of Hepatitis B-related Hepatocellular Carcinoma

Background: Hepatocellular carcinoma (HCC) is a prevalent and life-threatening tumor with high morbidity and mortality. Proper prediction and prognosis are incredibly stressed to diagnose HCC and increase patient survival. Objectives: This research aims to evaluate gene expression levels of pre-differentiated transcripts for those suffering from chronic hepatitis B (CHB) and HCC. Methods: To examine the previously analyzed peripheral blood mononuclear cells (PBMCs) transcriptomic array data, we selected seven differentially expressed genes (DEGs) in normal versus CHB and CHB versus HCC (CD44, SP3, USP8, E2F2, UFM1, IFN regulative factor binding protein 2 (IRF2BP2), and T-cell intracellular antigen 1 (TIA1)). The study included individuals with treatment-naïve CHB (n = 30) and primary HCC (n = 25) and healthy controls (n = 15). Subsequently, the expression of genes was assayed using qRT-PCR. A phylogenetic evaluation was performed using direct sequencing of HBsAg. Results: In HCC patients, 60% (n = 15) were HBeAg-positive. HBeAg was negative in all CHB patients, but all were anti-HBe-positive. The hepatitis B virus (HBV) load of HCC patients was more than that of CHB subjects. All patients were of the Iranian race and HBV D genotype. The expression of five transcriptional markers (CD44, SP3, USP8, E2F2, and UFM1) was higher in HCC patients than in CHB and healthy subjects, which was similar to the initial microarray data analysis. Conclusions: Transcriptional signatures may be related to the pathogenesis of HCC and used as diagnostic biological markers for the initial monitoring and prediction of HCC.

Occult Hepatitis B Infection among Hemodialysis in Tabriz, Northwest of Iran: Prevalence and Mutations within the S Region

Regardless of the extensive screening for the detection of hepatitis B surface antigen (HBsAg), hemodialysis (HD) patients are still severely at the risk of occult hepatitis B virus infection (OBI), especially in developing countries. OBI is defined as the presence of HBV DNA with undetectable HBsAg in the liver and/or Serum. This study aims to determine the prevalence of OBI in HD patients in Tabriz Province, northwest of Iran, and inquire about the mutations in the detected HBsAg. In this cross-sectional descriptive study, ELISA method assessed serum and plasma samples of 118 HBsAg-negative patients undergoing HD treatment for HBV serological markers (HBsAg and Anti-HBc). Specific primers by nested polymerase chain reaction have been utilized to examine HBV DNA; also, direct sequencing of surface genes was carried out to characterize the viral genotypes and S gene mutations. Finally, followed by real-time PCR, the quantity of viral load in OBI-positive patients was determined. A total of 118 HD patients were included (63.6% were male and 36.4% female), with an overall mean age of 60.8 ± 12.8 years old. The prevalence of antihepatitis B core antibody (Anti-HBc) in the study population was 26.3% (31/118). Five patients (4.2%) were positive for HBV DNA and labeled OBI-positive; their plasma HBV-DNA load was less than 100 IU/ml. Following the phylogenetic analysis, the samples with OBI roughly belonged to genotype D, subtype ayw2 and only two had mutations within the S ’gene’s major hydrophilic region (MHR), including T123I, C124F, and P127T. This study reports the prevalence of OBI in the HBsAg-negative HD patients being at a rate of 4.2%, which can be a clinically vital consideration in this region. HBV serologic screening approaches need to be renewed to cover nucleic acid testing in the setting of hemodialysis and all the other high-risk groups associated with it (i.e., blood and organ donors).

Detection and Quantification of Hepatitis B Virus Genomes in Peripheral Blood Mononuclear Cells of Chronic Hepatitis B Virus Infection, Cirrhosis, and Hepatocellular Carcinoma Patients

Background: Several studies have revealed that the hepatitis B virus (HBV) exists in peripheral blood mononuclear cells (PBMCs). It remains poorly understood whether HBV DNA and covalently closed circular DNA (cccDNA) can emerge in PBMCs of patients with different stages of HBV infection. Objectives: This study aimed to compare the detection of HBV DNA and quantification and presence of cccDNA within PBMC from patients with chronic hepatitis B (CHB), cirrhosis, and hepatocellular carcinoma (HCC). Methods: The present study was conducted on 120 participants (30 CHB patients, 30 cirrhosis patients, 30 HCC patients, and 30 healthy controls) from Tehran, Iran. HBV serological markers were tested by enzyme-linked immunosorbent assay (ELISA). PBMCs of all individuals were assayed for HBV DNA detection, quantification, and the presence of cccDNA. Results: Of 90 HBV patients, 58 (64.4%) were positive for HBV DNA in PBMCs. HBV DNA was detected in PBMCs isolated from 13/30 CHB, 20/30 cirrhosis, and 25/30 HCC patients. In addition, 6 (20%) CHB, 13 (43.3%) cirrhosis, and 16 (15.3%) HCC patients were cccDNA positive. The HBV viral loads in serums were statistically higher than the HBV viral loads of PBMCs (P < 0.001). A positive correlation was found between HBV DNA loads in serums and PBMCs of patients. Moreover, HBV DNA quantity of serums and PBMCs showed a significant association in terms of hepatitis B e antigen (HBeAg) status. Conclusions: HBV quantity in PBMCs correlated with serum HBV viral loads. HBV genomes in PBMCs may be a risk factor for HBV disease progression.

Characterization of Occult Hepatitis B Virus Infection Among Iranian Patients with Behcet's Disease; Correlation with Clinical Status

Background: Behcet's disease (BD) is a chronic multisystem vasculitis with an unknown etiology. During the past years, several reports are published on the occult hepatitis B infection (OBI), the presence of hepatitis B virus (HBV) DNA in the absence of HBsAg, in rheumatic diseases. Objectives: The current study aimed to, firstly, investigate the prevalence of OBI in patients with BD, and, secondly, its potential association with the clinical and therapeutic status of BD. Methods: HBV serological markers and HBV DNA were evaluated in 220 consecutive BD patients to detect OBI. Demographic and clinical data of OBI positive and negative groups were compared. Results: The mean age of patients was 39.24 (± 10.57), and 134 (62.9%) were male. The mean disease duration was 14.13 (± 8.63) years. No HBsAg positive case was found, but HBV DNA was found in 19 (8.6%) patients. The median viral load value was 475.84 copy/mL. We compared clinical data of 10 OBI positive and 156 OBI negative BD patients with complete and accessible data. There was no difference between the two groups concerning demographic characteristics (age, sex, and disease duration), different clinical manifestations, or types of medications (immunomodulatory, cytotoxic, and corticosteroids). Conclusions: This is the first study showing a rather high prevalence of OBI among BD patients. We did not find any correlation between OBI positivity and different clinical manifestations, medications, or HLA-B51. Further studies are needed on a larger group of patients and by molecular HBV evaluation (as well as serologic) regarding this possible association.

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.

Nucleotide Substitutions in Hepatitis B Viruses Derived from Chronic HBV Patients

Background

Mutations in the S gene (HBsAg), pre-core (PC), and basic core promoter (BCP) of the hepatitis B virus (HBV) infection are correlated with disease progression. This study assessed the frequency of mutations in the S gene, PC, and BCP regions in chronic hepatitis B (CHB) patients.

Methods

104 formerly known CHB patients who visited Tehran Hepatitis centers, were included. The viral load of samples was determined based on the TaqMan method. Regions of the S gene, PC and BCP were amplified by the nested PCR. Positive PCR products were sequenced and analyzed.

Results

33 successfully sequenced S gene region revealed all the derived strains were genotype D, with the majority (90.9%) belonging to the ayw2 subtype, and the rest (9.1%) to the ayw1 subtype. The prevalence of mutations was found to be 51.0% and 18.0% in the HBsAg and the Major Hydrophilic Region, respectively. 70.0% of amino acid changes within HBsAg occurred in different immune epitopes, of which 27.0% and 72.0% were located in B cell and Th epitopes, respectively. 26 successfully sequenced PC and BCP regions showed at least one mutation in 84.6% of the HBV strains. The PC and BCP mutations were G1896A (61.0%), G1899A (23.0%), A1762T/G1764A (23.0%) and G1764T/C1766G (26.0%). None of the strains with A1762T/G1764A mutation carried the G1764T/C1766G mutant.

Conclusions

Our results showed common mutations within HBsAg, occurring in immune epitopes, a high rate of G1896A mutations in the PC region, and a negative correlation between the emergence of A1762T/G1764A mutation and the G1764T/C1766G mutant in the BCP region.

Molecular analysis of occult hepatitis B infection among Iranian HIV-positive patients

Aim: The aims of this study were to find out the prevalence of occult hepatitis B infection (OBI) in HIV-1 patients, as well as to analyze the mutational patterns of OBI-positive individuals. Materials & methods: 172 HBsAg-negative, HIV-1-positive patients were selected according to data extracted from questionnaires. HBV serologic and molecular assays were performed. An extensive mutational analysis was applied using direct sequencing on HBsAg. Results: Thirty-one samples (18%) were OBI positive. Among 24 available OBI-positive samples, 17 (71%) contained at least one mutation only within ‘a’ determinant region of HBsAg. A stretch of mutations was found between amino acid positions 121 and 136. The physicochemical properties of individual amino acid substitutions and their potential impacts on 3D structure of ‘a’ determinant mutants were also determined. Conclusion: HBV serologic assays are not reliable markers to exclude occult HBV infection in HIV-positive patients.

Mutational analysis of reverse transcriptase and surface proteins of patients with partial virological response during mono and combination antiviral therapies in genotype D chronic hepatitis B

Introduction

The mutational pattern of chronic Hepatitis B virus (HBV) is unclear in patients who show incomplete response to antiviral therapy. The aims of this study were 1) to determine the benefit of combination therapy with adefovir dipivoxil (ADV) and Lamivudine (LAM) versus ADV or LAM alone in maintaining virological, biochemical and histological responses and 2) to investigate the patterns of mutations in the reverse transcriptase and surface proteins of HBV with LAM and/or ADF-resistant in partially-responded chronic hepatitis B (CHB) patients.

Methods

The study group consisted of 186 chronic HBV carriers who were admitted to the Tehran Hepatitis Network from 2010 to 2013. We retrospectively selected 86 patients who partially responded to different nucleoside analogue regimens. After 48 weeks of therapy, five groups of patients were defined including eight Lamivudine (LAM) Group (I), 30 Adefovir (ADV) Group (II), 16 ADV add on LAM Group (III), 32 ADV+LAM Group (IV), and 100 controls (no therapy). Reverse transcriptase (RT) and surface genes were amplified and sequenced for mutational analysis.

Results

All groups showed differences between mean values for age, gender, alanine transaminase (ALT), aspartate transaminase (AST), and HBV DNA levels groups showed significant differences than other groups (p < 0.05). The mutation frequencies for groups were I (1.7%), II (1.39%), III (2.28%), IV (2.0%), and V (0.38%). T54N, L80I/V, I91L/V, L180M, M204I/V, Q215P/S, and F221Y/S showed the highest number of mutations in all groups with different frequencies. Four new, unreported mutations were found.

Conclusion

Those patients who failed to respond in the first 48 weeks, whether they were receiving mono or combination therapy, should be tested genotypically, for the early modification of treatment.

Characterization of Occult Hepatitis B Infection Among Injecting Drug Users in Tehran, Iran

BACKGROUND

Hepatitis B virus (HBV) infection is a major health problem worldwide.

OBJECTIVES

The aim of this study was to investigate the frequency of occult hepatitis B infection (OBI) and its associated risk factors, together with the molecular characterization of the virus in injecting drug users of Tehran.

PATIENTS AND METHODS

The study consisted of 229 injecting drug users. Serum samples were collected and tested for the presence of hepatitis B core antibody (HBcAb) and hepatitis B surface antigen (HBsAg) by an enzyme-linked immunosorbent assay (ELISA). HBV B virus DNA was extracted from the serum samples, and a fragment of the S gene was amplified using the nested polymerase chain reaction. The genotype, subgenotypes, subtype, and S gene mutation of HBV were determined by direct sequencing. A phylogenetic tree was constructed using the neighbor-joining method.

RESULTS

Sixty-four (28%) participants were HBcAb positive, 59 cases were HBcAb positive and HBsAg negative, and 5 cases were HBsAg positive. Hepatitis B DNA was found in three HBsAg-positive cases. Thirteen of 59 (22%) individuals were hepatitis B DNA positive. The phylogenetic tree of hepatitis B DNA showed the existence of genotype D. The only significant correlation was between sharing a syringe and OBI.

CONCLUSIONS

In comparison with the rate of HBcAb positivity reported in other Iranian studies, the rate was higher in the present study. There were a few variations, genotypes, and subtypes among the infected injecting drug users. Further investigations are needed to unravel the molecular characterization of OBI.

Lamivudine Resistance and Precore Variants in Iranian Patients With Chronic Hepatitis B: Correlation With Virological and Clinical Features

Background:

Long-term lamivudine therapy, despite its initial effectiveness against hepatitis B virus (HBV), is associated with the emergence of drug resistance mutations in polymerase protein.

Objectives:

The aim of the present study was to determine the prevalence of precore and lamivudine drug resistance mutations in lamivudine treated patients with chronic B hepatitis.

Patients and Methods:

Sequential sera were obtained from 88 chronic HBV carriers who received lamivudine for more than 24 months. Polymerase and precore regions were directly sequenced for these groups: I (before treatment), II, and III (12 and 24 months after treatment, respectively).

Results:

All patients (100%) were contained genotype D, subtype ayw2. One (1.1%), 12 (13.6%), and 22 (25%) members of groups I, II, and III had the replacement of either isoleucine or valine instead of methionine in tyrosine-methionine-aspartate-aspartate (YMDD) motif, respectively. The frequency of mutations from 0 time point to 12 and 24 months showed that there was an increasing trend between sequential samples (P < 0.001). In group I, 31 (35.2%); II, 36 (41.0%) and III, 41 (46.6%) members had the precore stop codon mutations. The frequency of mutations from 0 time point to 12 and 24 months showed that there was an ascending trend between sequential samples. Indeed, frequency of precore stop codon was significantly increased with the passage of time (P < 0.001).

Conclusions:

Presence of drug resistance mutations among the patients was significant. Precore mutations were common amongst Iranian HBV chronic carriers under lamivudine therapy and these mutations were accompanied by clinical relapse.

Genogeography and Immune Epitope Characteristics of Hepatitis B Virus Genotype C Reveals Two Distinct Types: Asian and Papua-Pacific

Distribution of hepatitis B virus (HBV) genotypes/subgenotypes is geographically and ethnologically specific. In the Indonesian archipelago, HBV genotype C (HBV/C) is prevalent with high genome variability, reflected by the presence of 13 of currently existing 16 subgenotypes. We investigated the association between HBV/C molecular characteristics with host ethnicity and geographical distribution by examining various subgenotypes of HBV/C isolates from the Asia and Pacific region, with further analysis on the immune epitope characteristics of the core and surface proteins. Phylogenetic tree was constructed based on complete HBV/C genome sequences from Asia and Pacific region, and genetic distance between isolates was also examined. HBV/C surface and core immune epitopes were analyzed and grouped by comparing the amino acid residue characteristics and geographical origins. Based on phylogenetic tree and geographical origins of isolates, two major groups of HBV/C isolates—East-Southeast Asia and Papua-Pacific—were identified. Analysis of core and surface immune epitopes supported these findings with several amino acid substitutions distinguishing the East-Southeast Asia isolates from the Papua-Pacific isolates. A west-to-east gradient of HBsAg subtype distribution was observed with adrq+ prominent in the East and Southeast Asia and adrq- in the Pacific, with several adrq-indeterminate subtypes observed in Papua and Papua New Guinea (PNG). This study indicates that HBV/C isolates can be classified into two types, the Asian and the Papua-Pacific, based on the virus genome diversity, immune epitope characteristics, and geographical distribution, with Papua and PNG as the molecular evolutionary admixture region in the switching from adrq+ to adrq-.

Natural history of chronic hepatitis B virus infection

Hepatitis B virus infection represents a major global health problem. Currently, there are more than 240 million chronically infected people worldwide. The development of chronic hepatitis B virus-mediated liver disease may lead to liver fibrosis, cirrhosis and eventually hepatocellular carcinoma. Recently, the discovery of the viral entry receptor sodium taurocholate cotransporting polypeptide has facilitated new approaches for a better understanding of viral physiopathology. Hopefully, these novel insights may give rise to the development of more effective antiviral therapy concepts during the next years. In this review, we will discuss the natural history of hepatitis B virus infection including the viral biology, the clinical course of infection and the role of the immune response.

Characterization of overt and occult hepatitis B virus infection among HTLV-1 positive healthy carriers in the Northeast of Iran; AN HTLV-I endemic area

To date, no studies have provided data on hepatitis B virus (HBV) prevalence among asymptomatic, healthy human T-lymphotropic virus (HTLV-I) positive carriers. This sero- and molecular epidemiology study was performed on patients in the Northeast of Iran, which is an endemic area for HTLV-I infection. A total of 109 sera were collected from HTLV-I positive healthy carriers who were admitted to Ghaem Hospital, Mashhad City. All were tested for HBV serology and subsequently, real time PCR was carried out on the samples, regardless of the results of the serology. Standard PCR and direct sequencing were applied on positive samples. All cases were negative for HBsAg, Anti-HBc, and anti-HBs were positive in 34 (31.1%), and 35 (32%) individuals, respectively. There were 19 (17.4%) cases that were positive only for anti-HBs, and they had already received HBV vaccine. 16 (15%) were positive for both anti-HBs and anti-HBc, indicating a past-resolved HBV infection. 18 (16.5%) were isolated as anti-HBc, and 56 (51.3%) were negative for all HBV serological markers. Only one subject (0.9%) had detectable HBV DNA (2153 copy/ml), and assigned as being an occult HBV infection. The low prevalence of HBsAg, despite the high percentage of anti-HBc positive cases, might be related to the suppression effect of HTLV-I on surface protein expression. The low prevalence of HBV infection among HTLV-I positive healthy carriers from an endemic region, indicates that the epidemiology of HTLV-I and HBV coinfection is related to the endemicity of HBV in that region, rather than HTLV-I endemicity.

Molecular epidemiology of hepatitis delta virus in the Western Pacific region

BACKGROUND

Hepatitis delta virus (HDV) is a defective RNA virus requiring the presence of the hepatitis B virus (HBV) for the completion of its life cycle. Active replication of HDV can lead to severe hepatitis, and although present worldwide has an irregular geographical distribution, especially in the Asian Pacific region.

OBJECTIVES

The aim of this study was to determine the prevalence and molecular epidemiology of HDV isolates in Oceania following the 1998 evaluation of the hepatitis B vaccine program.

STUDY DESIGN

Sera collected from 184 hepatitis B surface antigen (HBsAg) positive Pacific Islanders living in Micronesia, Polynesia and Melanesia were tested for HDV RNA.

RESULTS

Twenty of 54 patients with chronic hepatitis B (CHB) from Kiribati were positive for serum HDV RNA (37%), whilst sera from patients with CHB from Tonga (59), Fiji (42) and Vanuatu (29) were negative. The mean HDV RNA load for the 20 samples was 7.00log10copies/mL. Phylogenetic analysis revealed that the Kiribati HDV isolates were of genotype 1 and clustered with a previously published isolate from Nauru forming a distinct clade of Pacific HDV. All Micronesian isolates contained a serine at codon 202 of large hepatitis delta antigen (L-HDAg) demonstrating possible relatedness to strains of HDV-1 of African origin.

CONCLUSIONS

This study has confirmed endemic HDV infection in Micronesia and identified Kiribati as having amongst the highest prevalence for HDV viraemia in patients with CHB. Further investigations are ongoing into the origins of this unique HDV Pacific strain, and its inter-relationship with HBV.

Prevalence and molecular analysis of occult hepatitis B virus infection isolated in a sample of cryptogenic cirrhosis patients in iran

OBJECTIVES

The aims of this study are to investigate the prevalence of occult hepatitis B virus infection among patients with cryptogenic cirrhosis and to analyze the relationship between surface protein variability and occult hepatitis B virus infection, which may be related to the pathogenesis of occult hepatitis B virus infection in cryptogenic cirrhosis. Occult hepatitis B virus infection is a well-recognized clinical entity characterized by the detection of hepatitis B virus DNA in serum and/or liver in the absence of detectable hepatitis B virus surface antigen, with or without any serological markers of a past infection.

METHODS

Sera from patients with cryptogenic chronic liver disease were tested for hepatitis B virus DNA using both real-time and nested PCR. In the detected hepatitis B virus DNA samples, the surface gene was analyzed for mutations.

RESULTS

Hepatitis B virus DNA was detected in 38% of patients, all of whom had a viral load below 10,000 copies/mL. All hepatitis B virus belonged to genotype D. There were no significant associations between occult hepatitis B virus infection status and age, gender, ALT/AST levels, viral load or serologic markers of previous hepatitis B virus infection. There were 14 mutations found in 5 patients; 6 were in the major hydrophilic region, of which 4 were Y134F assigning for the "a" determinant region. All patients who acquired Y134F contained S207R (within HLA-A2-restricted CTL epitope) as a combination.

CONCLUSION

Hepatitis B virus surface antigen variants may arise as a result of natural selection to evade the immune surveillance of the infected host, and subsequently may go undetected by conventional hepatitis B virus surface antigen screening tests. Etiological diagnosis of cryptogenic cirrhosis is significantly underestimated with current serology testing methods alone.

Prevalence of hepatitis delta virus (HDV) infection in chronic hepatitis B patients with unusual clinical pictures

BACKGROUND

Probably 5% of the HBV carriers have HDV super infection. The risk of fulminant hepatitis, cirrhosis and hepatocellular carcinoma is higher in superinfection than the settings when HBV is alone.

OBJECTIVES

The aim of this study was to evaluate the prevalence of HDV in Iranian HBV isolates and to compare their clinical and virological pictures as well as their HDV genetic variations with other worldwide isolates.

PATIENTS AND METHODS

81 carriers with positive results for HBsAg with upper limit ranges of ALT and low or undetectable levels of HBV viral load who did not respond to HBV therapy were selected. After RT amplification of HDV Delta antigen, direct sequencing and phylogenetic study were performed to explore the genotype(s) and nucleotide/amino acid variations.

RESULTS

12 (14.8%) patients had positive results for both HDV RNA and anti-HDV. The mean ALT level was higher in HDV positive patients (75.9 U/ML) than HBV-mono-infected individuals; however, the mean HBV viral load was lower in coinfected patients than HBV-mono-infected patients. Phylogenetically, genotype I was the only detected genotype, and the most closely related isolates were of Turkish, Italian and Mongolian origin. Within the delta Ag, there were 326 nucleotide mutations, of which 111 and 215 were silent and missense, respectively. The total number of amino acid substitution was 148; most were located in known functional/epitopic domains. There was no correlation between the numbers of amino acid mutations, with clinical, virological status of the patients.

CONCLUSIONS

HDV should be suspected in HBV carriers with unusual clinical and virological pictures. Relatedness of Iranian HDV isolates to Italian and Turkish sequences proposed a common Caucasian origin for the distribution of HDV genotype I in this ethnic group.

Variability of the preC/C region of hepatitis B virus genotype A from a South African cohort predominantly infected with HIV

Hepatitis B virus (HBV) is a serious global health problem, and HBV genotype is an important determinant of disease progression and treatment outcome. The aim of this study was to assess variations of the precore/core (preC/C) region in HBV genotype A. Sequencing of the preC/C and surface (S) genes of HBV was performed on plasma samples from 20 HBV/HIV co-infected and 5 HBV mono-infected individuals. All preC/C study sequences clustered with subgenotype A1, except for two which clustered with subgenotype D4 reference strains. The nucleotide and amino acid variability was far higher in the preC/C region than in the S region. Mutations associated with reduction or failure of HBV e-antigen (HBeAg) production were observed, with a preC start codon mutation being common (24%). Other mutations (e.g., P5H/L and I97L) associated with severe liver disease were also noticed, some of which were located in the major histocompatibility restricted sites. PreC/C intergenotype nucleotide divergence was >7%, while subgenotypes differed by 2.5-7%. Several study sequences were highly divergent from other African subgenotype A1 strains. This study showed that HBeAg-negative chronic hepatitis B is underestimated in subgenotype A1, and also highlighted the variant South African A1 strains. The major advantage of preC/C sequencing is that it informs patient management as HBeAg-negative chronic hepatitis B responds poorly to conventional interferon-α therapy, and some guidelines treat HBeAg-negative chronic hepatitis B differently from HBeAg-positive chronic hepatitis B. These data suggest that subgenotype A1 may be more involved in severe HBV-related diseases.

Hepatitis B virus surface protein mutations clustered mainly in CTL immune epitopes in chronic carriers: results of an Iranian nationwide study

Mutations within the coding region of hepatitis B surface antigen (HBsAg) have been found naturally in chronic carriers. To characterize the mutations of HBsAg from Iranian chronic carriers who were vaccine and/or medication naive. The surface genes from 360 patients were amplified and directly sequenced. The distribution of amino acid substitutions was classified according to different immune epitopes of the surface protein. All isolates belonged to genotype D. 222 (61.6%) of 360 patients contained at least one amino acid substitution. 404 (74.5%) of 542 amino acid changes occurred in different immune epitopes of HBsAg, of which 112 (27.7%) in 32 residues of B-cell epitopes (62 in the 'a' determinant); 111 (27.4%) in 32 residues of T helper; and 197 (48.7%) in 32 residues inside cytotoxic T lymphocyte (CTL) epitopes. One Th (186-197) and two CTL (28-51 and 206-215) epitopes were found to be hotspot motifs for the occurrence of 213 (52.7%) substitutions. 20 stop codons were identified in different epitopes. There was a significant association between amino acid substitutions and anti-HBe seropositivity; however, the correlation between such changes with viral load and ALT levels was not significant. In chronic hepatitis B virus(HBV) carriers, positive selection in particular outside the 'a' determinant appeared to exert influence on the surface proteins. These changes could be immune escape mutations naturally occurring due to the host immune surveillance especially at the T-cell level.

Naturally occurring core immune-escape and carboxy-terminal mutations\truncations in patients with e antigen negative chronic hepatitis B

INTRODUCTION

Hepatocellular injury is often progressive in patients with hepatitis B e antigen negative chronic hepatitis B (HBeAg -ve CHB). There is scant data on association of core mutations occurring in patients with HBeAg -ve CHB with severity of liver disease.

MATERIALS AND METHODS

Hundred and eighteen patients with chronic infection who were HBeAg negative, anti-HBe, and HBV DNA positive were enrolled. Precore and core regions were amplified, sequenced, and analyzed for precore, T helper, cytotoxic T lymphocytes (CTLs), B-cell epitope, and core carboxy-terminal region mutations.

RESULTS

Majority of patients were infected with HBV genotype D: 96 (81%) [D1: 16, D2: 55 and D5: 25] followed by genotype A1: 15 (13%) and genotype C: 7 (6%) [C1: 5 and unidentified subgenotype C: 2]. Classical (A1896) as well as nonclassical precore region mutations were detected in 30 (25%) and in 9 (7.6%) patients, respectively. Core immune escape, core carboxy-terminal mutations and truncations were detected in 61 (52%), 11 (9.3%), and 14 (12%) patients, respectively. Three core immune escape mutations were significantly higher in patients with coexisting precore stop codon compared with patients without precore stop codon mutation, cT12S (43 vs. 8%, p < 0.001), cS21T (16 vs. 3.4%, p < 0.026), and cE77D (30 vs. 4.5%, p < 0.002). When frequency of core immune escape mutations was compared among CHB and decompensated patients, and cT12S: (27 vs. 10%, p < 0.05), cS21T (16 vs. 1.35%, p < 0.01), cT67P/N: (20 vs. 4%, p < 0.001), cE113D (11.37 vs. 1.35%, p < 0.05), and cP130T/Q (7 vs. 0%, p < 0.001) mutations were found to be significantly higher in decompensated patients.

CONCLUSION

Core immune-escape mutations cT12S, cS21T, cT67P, cE113D, and cP130T/Q are significantly higher in decompensated liver disease patients and could influence the severity of liver disease in HBeAg -ve CHB patients.

High prevalence of occult hepatitis B virus infection in children born to HBsAg-positive mothers despite prophylaxis with hepatitis B vaccination and HBIG

BACKGROUND & AIMS

Occult hepatitis B virus (HBV) infection is a well-recognized clinical entity characterized by the detection of HBV DNA in serum and/or liver in the absence of detectable hepatitis B surface antigen (HBsAg). The frequency of the diagnosis depends on the relative sensitivity of both HBsAg and HBV DNA assays. We aimed at determining the prevalence of occult HBV infection in a high risk group of children who developed HBV infection despite immunoprophylaxis.

METHODS

The sera of 75 children born to HBsAg-positive mothers previously immunized by HBIG and prophylaxic vaccine regimen were assayed for HBV DNA by real-time PCR. Subsequently, the samples were tested using a sensitive standard PCR, with an independent set of primers for all HBV genes, and analyzed by direct sequencing.

RESULTS

HBV DNA was detected in 21/75 (28%) children, and ranged between 77 and 9240 copies/ml. All were positive for anti-HBs. Five (24%) children were found to be positive for anti-HBc, while anti-HBc-only positive individuals were not observed. Eight isolates (38%) did not carry any mutation. Thirteen infected children (62%) had at least one mutation in regions known to be involved in functional and/or immune epitope activity. Ten had G145R mutations.

CONCLUSIONS

HBV occult infection seems to be relatively frequent in immunized children born to HBsAg-positive mothers. HBsAg negativity is not sufficient to completely exclude HBV DNA presence. These findings emphasize the importance of considering occult HBV infection in hypo-endemic areas.

A rapid and reliable genotyping method for hepatitis B virus genotypes (A-H) using type-specific primers

Eight genotypes of HBV (A-H) are recognized. A simple, rapid, and more specific genotyping system for HBV involving PCR using type-specific primers is described. The complete genomes of 234 human HBV strains for all the genotypes submitted to GenBank were aligned. The type-specific primers were designed based on the differences in the sizes of bands for eight genotypes in two sets. This genotyping system was tested with 24 positive HBV DNA controls. PCR was performed using two sets of type-specific primers for each sample in two tube. All 24 samples were PCR positive and possessed type-specific bands. PCR mix containing set 1 primers revealed specific bands of genotypes B, C, F and G, whereas PCR mix containing set 2 primers revealed specific bands of genotypes A, D, E and H. Type-specific PCR products were identified accurately by their sizes in agarose gels. The simplicity and rapidity of this PCR assay may reduce the cost and complexity of recognizing these genotypes. This method may be useful for HBV genotyping in large-scale clinical and epidemiologic studies.

A new core promoter mutation and premature stop codon in the S gene in HBV strains from Iranian patients with cirrhosis

In order to define hepatitis B virus (HBV) mutational patterns in Iran, nucleotide sequences obtained from 91 patients and encompassing the precore, basal core promoter (BCP) and surface (S) regions, were compared. The patients were grouped as asymptomatic carriers, chronic active hepatitis or cirrhotic patients. Genotypes and mutations were determined by sequencing and phylogenetic analysis. All strains belonged to genotype D, and most of them to subgenotype D1. All but two strains specified ayw2, one ayw3 and one adw2 determinants. Two deletions of 8- or 20-bp were found in the X region in eight strains, six from patients with chronic active hepatitis. Eight of 21 strains from patients with cirrhosis harboured unusual mutations such as a stop codon at position 69 in the S region or a previously not described mutation in the BCP region ((1761)TC/ATTTG(1766)). All patients infected by strains with the stop codon mutation had detectable HBsAg and high viral load. The accumulation of mutations found in the BCP and S regions in HBV strains from patients with chronic active hepatitis and cirrhosis may predict disease progression in Iranian HBsAg carriers.

Construction and expression of eukaryotic plasmids containing lamivudine-resistant or wild-type strains of Hepatitis B Virus genotype C

AIM: To construct eukaryotic expression plasmids of full-length Hepatitis B Virus (HBV) genotype C genome, which contain lamivudine-resistant mutants (YIDD, YVDD) or wild-type strain (YMDD), and to observe the expression of HBV DNA and antigens [hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg)] of the recombinant plasmids in HepG2 cells.

METHODS: Three HBV full-length genomes were amplified from the plasmids pMD18T-HBV/YIDD, pMD18T-HBV/YVDD and pMD18T-HBV/YMDD, using PCR. Three recombinant plasmids were generated by inserting each of the PCR products into the eukaryotic expression vector pcDNA3.1 (+), between the EcoRI and HindIII sites. After being characterized by restriction endonuclease digestion, and DNA sequence analysis, the recombinant plasmids were transfected into HepG2 cells. At 48 and 72 h post-transfection, the levels of intracellular viral DNA replication were detected by real-time PCR, and the expression of HBsAg and HBeAg in the cell culture supernatant was determined by ELISA.

RESULTS: Restriction endonuclease digestion and DNA sequence analysis confirmed that the three recombinant plasmids were correctly constructed. After transfecting the plasmids into HepG2 cells, high levels of intracellular viral DNA replication were observed, and HBsAg and HBeAg were secreted into the cell culture supernatant.

CONCLUSION: Eukaryotic expression plasmids pcDNA3.1 (+)-HBV/YIDD, pcDNA3.1 (+)-HBV/YVDD or pcDNA3.1 (+)-HBV/YMDD, which contained HBV genotype C full-length genome, were successfully constructed. After transfection into HepG2 cells, the recombinant plasmids efficiently expressed HBV DNA, HBsAg and HBeAg. Our results provide an experimental basis for the further study of HBV lamivudine-resistant mutants.

Hepatitis B virus genotype B is associated with better response to thymosin alpha1 therapy than genotype C

Hepatitis B virus (HBV) genotype has been reported to correlate with response to interferon treatment in several studies. The relationship between HBV genotype and thymosin alpha1 (T-alpha1) treatment is unknown. We retrospectively examine HBV genotypes, precore and core promoter mutations in patients treated with Talpha1 and analyse the correlation between complete response [alanine aminotransferase (ALT) normalization plus seroclearance of HBeAg and HBV-DNA] and HBV genotype. It consisted 98 patients with chronic hepatitis B randomly allocating to three groups: (i) T6 group (n = 32) received a 26-week course of Talpha1 1.6 mg two times a week; (ii) T12 group (n = 34) received the same regimen as T6 group, but Talpha1 therapy extended for 52 weeks; (iii) T0 group (n = 32) served as a control and was followed up for 18 months without specific treatment. Stepwise logistic regression analysis showed that genotype (OR, 3.747; 95% CI, 1.066-13.170; P = 0.039), precore mutation (OR, 6.285; 95% CI, 1.874-21.086; P = 0.003) and Talpha-1 treatment (OR, 12.045; 95% CI, 2.220-65.354; P = 0.004) as independent factors associated with complete response. The complete response of Talpha-1 therapy was higher in patients with genotype B compared to patients with genotype C (52%vs 24%; P = 0.036) and in patients with precore mutation (64%vs 19%; P = 0.002). In conclusion, genotype, presence of precore mutation and Talpha-1 therapy were independent predictors to complete response. Genotype B, compared to genotype C, is associated with a higher response rate to T-alpha1 therapy.

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.

Genome-wide characterisation of hepatitis B mutations involved in clinical outcome

Infection with the hepatitis B virus (HBV) leads to different disease outcomes, which can be broadly divided into three categories: acute mild infection, 'fulminant' and chronic hepatitis (long-term persistent form of the infection). The factors that influence the development of these different disease states are poorly understood and may include viral polymorphisms. To investigate this possibility, we analysed 116 published complete HBV genomes for which we knew disease outcome and had access to associated information on patients (age, sex and geographic origin). Our best statistical model correctly classified 72% of the cases and retained age and sex of the patient, as well as 29 candidate mutations. With the exception of one mutation in the X gene, all were located in the viral polymerase, suggesting this gene plays a critical role in clinical outcome. Our results highlight the importance of the genetics of HBV strains in the evolution of the disease and demonstrate that disease outcome can be predicted to a surprisingly large extent with a limited number of host and viral factors.

Variability and conservation in hepatitis B virus core protein

Background

Hepatitis B core protein (HBVc) has been extensively studied from both a structural and immunological point of view, but the evolutionary forces driving sequence variation within core are incompletely understood.

Results

In this study, the observed variation in HBVc protein sequence has been examined in a collection of a large number of HBVc protein sequences from public sequence repositories. An alignment of several hundred sequences was carried out, and used to analyse the distribution of polymorphisms along the HBVc. Polymorphisms were found at 44 out of 185 amino acid positions analysed and were clustered predominantly in those parts of HBVc forming the outer surface and spike on intact capsid. The relationship between HBVc diversity and HBV genotype was examined. The position of variable amino acids along the sequence was examined in terms of the structural constraints of capsid and envelope assembly, and also in terms of immunological recognition by T and B cells.

Conclusion

Over three quarters of amino acids within the HBVc sequence are non-polymorphic, and variation is focused to a few amino acids. Phylogenetic analysis suggests that core protein specific forces constrain its diversity within the context of overall HBV genome evolution. As a consequence, core protein is not a reliable predictor of virus genotype. The structural requirements of capsid assembly are likely to play a major role in limiting diversity. The phylogenetic analysis further suggests that immunological selection does not play a major role in driving HBVc diversity.

Hepatitis B virus genotypes, core gene variability and ethnicity in the Pacific region

BACKGROUND/AIMS

The world-wide distribution of hepatitis B virus (HBV) genotypes follows a geographic pattern under the influence of ethnic background.

METHODS

Forty eight core genes from four pacific islands were compared with the following findings.

RESULTS

First, island-specific variant substitutions were found for only two out of four islands. Second, 11 amino acid and 90 nucleotide changes specific for pacific genotypes C and D were defined. Third, the nucleotide diversity of genotype C (all but one were silent) was greater than that of genotype D.

CONCLUSIONS

These results suggest an early appearance of genotype C in the pacific with few subsequent amino acid changes because of shared immunological responses across the region followed by random silent changes, some of which reflect isolation of individual island populations. Genotype D appeared later.