Precore mutation enhances viral replication to facilitate persistent infection especially in HBeAg-negative patients.

Naturally occurred precore (PC, G1896A) and/or basal core promoter (BCP, A1762T/G1764A) mutations are prevalent in chronic HBV-infected patients, especially those under HBeAg-negative status. However, the replicative capacity of HBV with PC/BCP mutations remains ambiguous. Herein, meta-analysis showed that, only under HBeAg-negative status, the serum HBV DNA load in patients with PC mutation was 7.41-fold higher than those without the mutation. Both PC mutation alone and BCP â€‹+ â€‹PC mutations promoted HBV replication in cell and hydrodynamic injection mouse models. In human hepatocyte chimeric mouse model, BCP â€‹+ â€‹PC mutations led to elevated replicative capacity and intrahepatic core protein accumulation. Mechanistically, preC RNA harboring PC mutation could serve as mRNA to express core and P proteins, and such pgRNA-like function favored the maintenance of cccDNA pool under HBeAg-negative status. Additionally, BCP â€‹+ â€‹PC mutations induced more extensive and severe human hepatocyte damage as well as activated endoplasmic reticulum stress and TNF signaling pathway in livers of chimeric mice. This study indicates that HBeAg-negative patients should be monitored on HBV mutations regularly and are expected to receive early antiviral treatment to prevent disease progression.

Acute hepatitis B in pregnancy with surprisingly rapid clearance of serum HBs antigen associated with a favourable outcome.

Acute hepatitis B (AHB) is usually asymptomatic, but it can progress to chronic hepatitis B (HB) defined by HB surface antigen (HBsAg) persisting beyond 6 months. Nevertheless, the delay of HBsAg seroclearance is not well-defined. During pregnancy, the immune system of the pregnant women is altered and delayed HBsAg loss can be observed, leading to chronic infection. Here, we present an uncommon case of AHB in a pregnant woman in whom rapid HBsAg seroclearance (52 days after AHB) was associated with a favourable outcome (no injury to liver). This patient received tenofovir disoproxil fumarate promptly after diagnosis. The case raises questions about the use of antiviral treatment in AHB. This is generally not recommended in AHB, but it would be potentially useful in pregnant women to reduce the risk of chronic HB infection and could also prevent the transmission of the maternal precore mutation, thus reducing the significant risk of fulminant hepatitis in the infant. This case also highlights the impact of the hepatitis B virus (HBV) genotype and precore/core mutations on the clinical course of the disease.

Spontaneous reactivation of hepatitis B virus with a frameshift mutation in the precore region in an elderly hepatitis B virus carrier with lifestyle-related diseases.

A 76-year-old woman with spontaneous reactivation of hepatitis B virus (HBV) without any immunosuppressants who had been successfully treated with tenofovir alafenamide fumarate (TAF) was reported. The patient was admitted to our hospital because of acute exacerbation of the liver function and jaundice. She had been found to have chronic HBV infection with a normal liver function and had been treated for lifestyle-related diseases, such as diabetes mellitus, dyslipidemia and hypertension, for over 10 years at a local clinic. At admission, her serum HBV DNA was high (7.3 log IU/mL), and anti-hepatitis B core protein immunoglobulin M was slightly elevated (1.47 S/CO). Due to the absence of known risk factors for HBV reactivation, the reactivation was regarded as "spontaneous". After the initiation of the nucleotide analog TAF, her liver function gradually improved with a decrease in the HBV DNA load. Her HBV genome was typed as subgenotype B1 and possessed a frameshift mutation due to an insertion of T after nucleotide (nt) 1817 and G to A mutations at nt 1896 and nt 1899 (G1896A/G1899A) in the precore region as well as serine to glutamine substitution of amino acid 21 in the core protein. In addition to these viral mutations, aging and complications of lifestyle-related diseases in the present case may have been responsible for the spontaneous HBV reactivation. Careful observation and management of aged HBV carriers with underlying diseases are needed even when persistent HBV infection is free from symptoms and liver dysfunction and no immunosuppressive conditions are involved.

Human hepatocytes apoptosis induced by replication of hepatitis B virus subgenotypes F1b and F4: Role of basal core promoter and preCore mutations.

In the context of pathogenesis of HBV infection, HBV genotypes and mutants have been shown to affect the natural course of chronic infection and treatment outcomes. In this work, we studied the induction of apoptosis by the replication of HBV subgenotypes F1b and F4, and the naturally occurring mutants BCP and preCore. Both subgenotypes F1b and F4 HBV genome transfections induced cell death by apoptosis in human hepatocytes. The BCPdm (A1762T/G1764A) and preCore (G1896A) mutants induced higher levels of apoptosis than the wt virus. This increase in apoptosis was not associated with the enhanced viral replication of the variants. HBV-mediated apoptosis was independent of viral subgenotypes, and associated with the modulation of members of the regulatory Bcl-2 family proteins expression in the mitochondrial apoptotic pathway. Finally, the apoptosis induction increase observed for the preCore mutants suggests that HBeAg might have an anti-apoptotic effect in human hepatocytes.

Influence of the basal core promoter and precore mutation on replication of hepatitis B virus and antiviral susceptibility of different genotypes.

Mutations in the basal core promoter (BCP) and precore (PC) regions of the hepatitis B virus (HBV) are more common in genotypes B and C than in genotype A, suggesting that these mutations might affect replication competency depending on genotype. The purpose of the study was to investigate the influence of these mutations on the capacity of HBV for replication and antiviral drug susceptibility according to genotype. Genotypes A, B, and C of HBV strains with a BCP mutation, PC mutation, or BCP + PC mutation were made by site-directed mutagenesis. Replication competency of each construct and susceptibility to nucleos(t) ide analogues were tested in an Huh7 cell line. In genotype A, the BCP and BCP + PC mutations increased the viral replication around 6.5 times compared with the wild type, and the PC mutation alone similarly increased the viral replication around three times. In genotypes B and C, all three mutant types increased viral replication to a similar extent, regardless of mutation pattern. Interestingly, the BCP mutation appeared to have a greater effect on viral replication in genotype A than in genotypes B and C. This finding was unexpected because the BCP mutation is more common in HBV genotypes B and C. Moreover, the BCP, PC, and BCP + PC mutations decreased the sensitivity of HBV to antiviral agents to various degrees (2- to 10-fold) regardless of genotype. In conclusion, BCP and PC mutations increased viral replication regardless of HBV genotype and decreased in vitro antiviral susceptibility to the nucleos(t) ide analogues.

HBsAg, HBeAg and HBV DNA level changes and precore/basal core promoter mutations in the natural history of chronic hepatitis B in Indonesian patients.

INTRODUCTION: Chronic hepatitis B (CHB) is a state of complex interactions between the hepatitis B virus (HBV) and host. We studied the changes in hepatitis B surface antigen (HBsAg), hepatitis B 'e' antigen (HBeAg) and HBV DNA levels, considering the implications of HBV genotype, basal core promoter (BCP) A1762T/G1764A and precore G1896A mutations in CHB. METHODS: One hundred fifty-two treatment-naïve CHB patients were classified into immune-tolerant (IT), immune-clearance (IC), low/non-replicative (LR) and 'e'-negative hepatitis B (ENH) phases, based on HBeAg status, HBV DNA and ALT levels. HBV DNA was detected and quantified by polymerase chain reaction, then analyzed by sequencing. HBsAg and HBeAg levels were measured serologically. RESULTS: HBsAg and HBV DNA levels varied between CHB phases, with HBsAg highest in IT and lowest in LR, and HBV DNA high in IT and IC, and lowest in LR. Both markers increased in ENH. Correlation between HBsAg and HBV DNA was significant in IT and IC, modest in ENH, but missing in LR. HBeAg and HBV DNA levels were dissociated in HBeAg-positive patients. Genotypes B and C were similarly distributed, with precore mutations higher in HBeAg-negative patients and BCP mutations comparable in all phases. Temporal association between HBeAg seroconversion and an increase of BCP/precore mutations was observed. CONCLUSION: HBsAg and HBV DNA levels were high and correlated in early CHB phases and dissociated after HBeAg seroconversion, indicating different controls affecting HBV replication and HBsAg production. Selection of BCP/precore mutants may affect disease course and explain the HBeAg-HBV DNA dissociation, a precaution for clinical application of quantitative HBeAg.

Prevalence and clinical significance of hepatitis B Basal core promoter and precore gene mutations in southern Iranian patients.

BACKGROUND AND AIMS: To investigate the prevalence and pattern of PC and BCP mutations and their clinical significance in patients with genotype D chronic hepatitis B infection in the Fars province of southern Iran. MATERIALS AND METHODS: From January 2007 to March 2008, we evaluated 44 patients with chronic hepatitis B infection who were referred to our hepatology clinics affiliated with the Shiraz University of Medical Science. All Patients were HBeAg Negative and HBeAb positive. Basal core promoter and precore mutations in these patients were evaluated with clinical phenotype and laboratory tests. RESULTS: The mean age of the patients was 37.21 ± 10.54 years. Twenty-seven patients (61.4%) had no mutations, whereas 17 patients (38.6%) had mutations in the precore or basal core promoter regions or both. The mean serum ALT level in mutation-free patients was 59.74 ± 55.86 IUL, whereas patients with PC and BCP mutations had a mean serum ALT level of 71.35 ± 59.49 IUL. The mean serum AST level in patients with mutations was higher than for patients without mutations (59.53 ± 41.35 IUL vs. 40.65 ± 25.21 IUL, respectively). There was no statistically significant difference between the mutation and mutation-free groups in terms of age, sex, and liver enzyme levels (P > 0.05). Fourteen of the 44 patients (31.8%) had mutations in the precore region (G 1896A). 17 patients (38.6%) had mutations in basal core promoter region. CONCLUSION: This study revealed a high prevalence of precore and basal core promoter mutations in southern Iran. Although no statistically significant difference was noted in liver enzymes, patients with mutations had higher liver enzymes in comparison with mutation-free patients.

Prevalence of the precore G1896A mutation in Chinese patients with e antigen negative hepatitis B virus infection and its relationship to pre-S1 antigen

This study investigated the prevalence of the precore G1896A mutation in Chinese patients with hepatitis B e antigen (HBeAg) negative HBV infection and its relation to serum HBV pre-S1 antigen. The overall prevalence of the precore G1896A mutation was 72.6 percent in HBeAg-negative Chinese patients with detectable serum HBV DNA. The prevalence of the precore G1896A is significantly higher in Chinese HBeAg-negative patients with chronic hepatitis B than that in inactive HBV carriers with detectable serum HBV DNA. Serum pre-S1 and the precore G1896A mutation were simultaneously detected in most of Chinese HBeAg-negative patients.

Prevalence of the precore G1896A mutation in Chinese patients with e antigen negative hepatitis B virus infection and its relationship to pre-S1 antigen.

This study investigated the prevalence of the precore G1896A mutation in Chinese patients with hepatitis B e antigen (HBeAg) negative HBV infection and its relation to serum HBV pre-S1 antigen. The overall prevalence of the precore G1896A mutation was 72.6% in HBeAg-negative Chinese patients with detectable serum HBV DNA. The prevalence of the precore G1896A is significantly higher in Chinese HBeAg-negative patients with chronic hepatitis B than that in inactive HBV carriers with detectable serum HBV DNA. Serum pre-S1 and the precore G1896A mutation were simultaneously detected in most of Chinese HBeAg-negative patients.

Hepatitis B virus genotype E detected in Brazil in an African patient who is a frequent traveler

Genotype E of hepatitis B virus (HBV) has not been described in Brazil and is found mainly in Africa. Genotype A is the most prevalent in Brazil, and genotypes B, C, D, and F have already been reported. We report here an HBV genotype E-infected patient and some characterization of surface (S) protein, DNA polymerase (P) and precore/core (preC/C) coding regions based on the viral genome. The patient is a 31-year-old black man with chronic hepatitis B who was born and raised in Angola. He has been followed by a hepatologist in São Paulo, Brazil, since November 2003, and he is a frequent traveler to Latin America, Africa, and Europe. In 2003, he was diagnosed with HBV infection and started treatment with lamivudine with the later addition of adefovir dipivoxil. No known risk factor was identified. Serologically, he is HBsAg and anti-HBe positive, but HBeAg and anti-HBs negative. DNA sequence analysis of the S/P region confirmed that this patient is infected with genotype E, subtype ayw4. The preC/C region showed G1896A and G1899A mutations but no mutations in the basal core promoter. Nucleotide substitutions common in genotype E were also observed (C1772, T1858 and A1757). Although this is not an autochthonous case and there is no evidence of further spread, the description of this case in Brazil highlights the current risk of viral genotypes spreading with unprecedented speed due to constant travel around the world.

Prevalência de genótipos e de mutantes pré-core A-1896 do vírus da hepatite B e suas implicações na hepatite crônica, em uma população da Amazônia oriental / Prevalence of hepatitis B virus genotypes and the occurrence of precore mutation A-1896 and to correlate them with the clinical presentation of chronic hepatitis, in a population group of the eastern Amazon region

A infecção pelo virus da hepatite B apresenta amplo espectro de manifestações clínicas. Objetivando conhecer os genótipos do HBV mais prevalentes e determinar a ocorrência da mutação pré-core A-1896, em uma população da Amazônia oriental, correlacionando com o diagnóstico clínico, foram selecionados 51 pacientes portadores crônicos de HBsAg e HBV-DNA positivos e divididos em três grupos: grupo A (n=14, pacientes assintomáticos); grupo B (n=20, sintomáticos HBeAg positivos) e grupo C (n=17, sintomáticos HBeAg negativos), sendo usado o sequenciador automático ABI modelo 377 para identificação de genótipos e mutantes pré-core. Os resultados evidenciaram o genótipo A como o mais prevalente, 81,8%, 89,5% e 93,7%, nos grupos A, B e C, respectivamente. A mutação pré-core A-1896 foi encontrada em 11,5% (3/26), sendo todos assintomáticos. Concluiu-se que na população estudada o genótipo A foi o mais prevalente e houve baixa ocorrência do mutante pré-core A-1896, ambos não se constituindo fatores agravantes da doença hepática.

Hepatitis B virus (HBV) infection presents itself with a variety of clinical manifestations. The present work aims to describe the prevalence of HBV genotypes and the occurrence of precore mutation A-1896 in a population group of the Eastern Amazon region of Brazil and to correlate them with the clinical presentation of chronic HBV infection. 51 HBsAg carriers (HBV-DNA positive) were selected and divided into three groups: A (14 asymptomatic subjects), B (20 HBeAg positive symptomatic patients) and C (17 HBeAg negative symptomatic patients). Using an automa ed DNA sequencer ABI model 377 by sequencing for determined of genotypes and precore mutation. The results showed that the genotype A was the most commonly found (81,1%, 89,5% and 93,7% in groups A, B and C, respectively) and precore mutation A-1896 was described in 11,5% (3/26) of group A subjects. Genotype A of HBV was the most prevalent (89,1%) and low occurrence of precore mutation A-1896, both not associate with the worst outcome of the chronic infection of HBV.

The Prevalence and Clinical Significance of Precore and Core Promoter Mutations in Korean Patients with hronic Hepatitis B Virus Infection / 대한간학회지

BACKGROUND/AIMS: Precore and core promoter mutations of hepatitis B virus (HBV) have been reported in Korea but their prevalence and clinical significance have not been determined. The aims of this study were to determine the prevalence of precore and core promoter mutations and their relationships to hepatitis B e antigen (HBeAg) status, viral replication level, and severity of liver disease in Korea. METHODS: Among the patients who visited the Liver Diseases Clinics (Chung Ang University Hospital) between December 1998 and August 1999, 150 patients were randomly selected: 50 HBeAg-positive HBV-DNA positive patients by a branched DNA (bDNA) assay, 50 HBeAg-negative bDNA-positive patients, and 50 HBeAg-negative bDNA-negative patients. Serum HBV-DNA was amplified by a polymerase chain reaction (PCR) in these patients and the core promoter/precore HBV sequence was determined in 135 of the patients whose sera were positive for HBV-DNA by PCR. RESULTS: All of the 135 determined HBV-DNA sequences had HBV genotype with T at nucleotide 1858. Precore mutation (A1896) was detected in 95.7% of HBeAg-negative bDNA-positive patients and 94.9% of HBeAg-negative bDNA-negative patients. In HBeAg-positive patients 88% had wild type and 12% had mixture of wild type and A1896 mutant. Core promoter TA mutation (T1762/A1764) was detected in 93.5% of HBeAg-negative bDNA-positive patients, 94.9% of HBeAg-negative bDNA-negative patients and 74% of HBeAg-positive patients. No correlation was found between the presence of precore/core promoter mutations and liver disease severity or HBV-DNA levels. CONCLUSION: Precore stop codon mutation occurred almost invariably, along with HBeAg seroconversion, irrespective of subsequent viral replication levels or disease severity. Core promoter TA mutation was frequent both in the HBeAg-positive patients and HBeAg-negative patients irrespective of viral replication levels or disease severity.