Precore G1896A Mutation Research Articles

HBV precore G1896A mutation promotes growth of hepatocellular carcinoma cells by activating ERK/MAPK pathway

Chronic hepatitis B virus (HBV) infection is one of the leading causes of hepatocellular carcinoma (HCC). The HBV genome is prone to mutate and several variants are closely related to the malignant transformation of liver disease. G1896A mutation (G to A mutation at nucleotide 1896) is one of the most frequently observed mutations in the precore region of HBV, which prevents HBeAg expression and is strongly associated with HCC. However, the mechanisms by which this mutation causes HCC are unclear. Here, we explored the function and molecular mechanisms of the G1896A mutation during HBV-associated HCC. G1896A mutation remarkably enhanced the HBV replication in vitro. Moreover, it increased tumor formation and inhibited apoptosis of hepatoma cells, and decreased the sensitivity of HCC to sorafenib. Mechanistically, the G1896A mutation could activate ERK/MAPK pathway to enhanced sorafenib resistance in HCC cells and augmented cell survival and growth. Collectively, our study demonstrates for the first time that the G1896A mutation has a dual regulatory role in exacerbating HCC severity and sheds some light on the treatment of G1896A mutation-associated HCC patients.

LCR based quick detection of hotspot G1896A mutation in patients with different spectrum of hepatitis B

G1896A switch is one of the hotspots in subjects affected with hepatitis B. This hotspot mutation is observed in all the different spectrum of hepatitis B, and it has a very dangerous and a long lasting effect. The major purpose of the study was to screen G1986A mutations at a large scale and also to establish ligase chain reaction as a mutation testing tool. Polymerase chain reaction (PCR) and Nucleotide Sequencing was done to identify the G1896A mutation in the precore region of the genome. All the 331 HBV positive patients were screened. Almost 29% (24/82) of the cases remarkably had the presence of G1896A mutation confirmed by LCR and direct sequencing.The precore G1896A mutation is responsible for one third of the patients suffering from precore stop codon mutation. It clearly exhibits that LCR is 100% in sync with direct sequencing and is extremely reliable and the results are highly reproducible.

Virological and Clinical Characteristics of Hepatitis B Virus Genotype A.

Hepatitis B virus (HBV) infection is one of the most prevalent chronic viral infections in humans. The overall prevalence of hepatitis B surface antigen (HBsAg) is reported to be 3.6%; however, it varies depending upon the geographic area. HBV is classified into ten genotypes (A through J) on the basis of an intergroup genomic divergence of > 8%. Specifically, HBV genotype A exhibits several unique virological and clinical characteristics and can be further classified into seven subtypes. Among them, subtype A2 or Ae (A2/[e]) is occasionally responsible for nosocomial infection and among homosexual males. Regarding virological factors, the G1896A precore mutation is rarely observed in genotype A as it would disrupt an essential stem-loop structure in the ε signal essential for pregenomic RNA packaging. HBV genotype A also harbors a 6-nucleotide C-terminal insertion in the hepatitis B-e antigen (HBeAg) precursor, resulting in a variable-length HBeAg protein product observed in serum of positive patients. These molecular traits likely contribute to the specific clinical presentation of genotype A-infected patients, such as mild acute hepatitis B (AHB), longer persistence of HBsAg positivity in AHB, and increased chronicity after AHB in adults. However, genotype A shows a better response to interferon than other genotypes in chronic hepatitis B patients. Here, we review the virological and clinical characteristics of HBV genotype A that will be useful in elucidating the association among persistent viral infection, host genetic factors, and treatment in future studies.

Sequence analysis and functional characterization of full-length hepatitis B virus genomes from Korean cirrhotic patients with or without liver cancer

This study aimed to identify and characterize mutations in the hepatitis B virus (HBV) genome associated with advanced liver diseases. The 3.2-kb HBV genome of the C2 subgenotype was amplified from sera of 18 cirrhotic Korean patients with (10) or without (8) hepatocellular carcinoma (HCC), and two clones per patient were characterized by transient transfection experiments in human hepatoma cells. While A1762T/G1764A core promoter mutations were highly prevalent in both groups, the G1896A precore mutation to abolish hepatitis B e antigen (HBeAg) expression was more common in HCC clones (55% vs. 20%). High replication capacity was mostly found in HCC clones and associated with core promoter mutations, whereas more non-HCC clones harbored a nonfunctional core gene (34% vs. 8%). Large in-frame deletions in the preS region were found in 60% of HCC clones and 38% of non-HCC clones. They removed the first 11 residues of large envelope protein or impaired small envelope protein expression, or deleted a neutralizing epitope in the preS2 domain. Additional point mutations prevented middle envelope protein expression, or caused nonsense mutations in the preS or S region to truncate large and/or small envelope protein. Consequently, many clones were unable to express or secrete hepatitis B surface antigen (HBsAg). In conclusion, mutations associated with the advanced stage of chronic HBV infection are complex and diverse. Host immune pressure most likely selected for mutations in the HBV genome to abolish or reduce HBeAg or HBsAg production, to enhance genome replication, or to escape neutralizing antibodies. Some of these mutations may contribute to liver cirrhosis or HCC development.

Intergenotype recombinant analysis of full-length hepatitis B virus genomes from 516 Chinese patients with different illness categories.

This study aimed to reveal characteristics and clinical relevance of HBV intergenotypic recombinants. Serum samples of 516 patients from Northern China were collected, including 131 with acute hepatitis B (AHB), 239 with chronic hepatitis B (CHB), and 146 with acute-on-chronic liver failure (ACLF). Full-length HBV genomes were sequenced and HBV genotypes were analyzed. Genotypes C, B, D, and intergenotypic recombinants were detected in 71.12% (367/516), 19.96% (103/516), 0.78% (4/516), and 8.14% (42/516) of the patients. The latter comprised 21 with AHB, 10 with CHB, and 11 with ACLF; and the occupations of intergenotypic recombinants in AHB, CHB, and ACLF groups were 16.03%, 4.18%, and 7.53% (P < 0.01), respectively. HBV B/C and C/D hybrids accounted for 85.71% (36/42) and 14.29% (6/42) of the intergenotypic recombinants. In AHB and CHB groups, serum HBV DNA levels were significantly lower in patients with intergenotypic recombinants than those without intergenotypic recombinants. Difference in basal core promoter A1762T/G1764A mutations and precore G1896A mutation incidences was not significant between B/C recombinant and genotypes B or C virus, although the significance was there between genotypes B and C viruses. Clonal sequence analysis showed that intergenotypic recombinant viral strains existed in single or in concomitance with other genotype virus. Phenotypic analysis showed that viral replication capacity was similar between recombinant and non-recombinant strains in tested samples. Taken together, the occurrence of intergenotypic recombinant HBV is relatively low in HBV-infected patients in Northern China, and intergenotypic recombinant HBV infection is likely favorable to induce an acute course of disease. J. Med. Virol. 89:139-145, 2017. © 2016 Wiley Periodicals, Inc.

Hepatitis B virus precore G1896A mutation in chronic liver disease patients with HBeAg negative serology from North India.

Hepatitis B with precore stop codon mutation is related with severe liver damage in HBeAg negative patients. It is of utmost importance to screen the G1896A precore mutation. The study was designed to assess the impact of G1986A mutations in patients with different clinical spectra of the liver disease by PCR–LCR. 210 HBV positive patients with HBeAg negative serology of different kind of liver diseases (AVH = 72, FH = 21, CH = 79, Cirrhosis = 20 and HCC = 18) were screened. Patients were screened for the presence or absence of precore G1896A mutation by PCR–LCR. Direct nucleotide sequencing was done to confirm the results of LCR. Precore mutant in HCC was 94.4% (17/18), 85.7% (18/21) in FH, 60% (12/20) in liver cirrhosis, 48.1% (38/79) in chronic hepatitis and 27.7% (20/72) in AVH cases. The serum ALT level was statistically significant between HBeAg negative WT and G1896A mutants in chronic hepatitis cases. ALT level and HBV DNA level was slightly raised in the pre core mutant but and was not significant. Genotype D had a higher prevalence (79.5%) as compared to genotype A (20.5%). The mutations detected by PCR–LCR were in 100% concordance with direct sequencing. The exceptionally high prevalence of G1896A in FH and HCC demonstrates that the precore mutants are strongly associated with the progression of liver diseases in patients with HBeAg negative serology. The findings are also suggestive of screening HBV precore G1896A mutation particularly in HBeAg negative cases. The precore G1896A mutation increases proportionately in severe form of liver diseases. LCR can be a suitable tool for screening of G1896A mutations.

Viral factors and outcome of chronic hepatitis B revisited.

Virus-host interactions during chronic hepatitis B virus (HBV) infection allow the distinction of several phases, defined according to virological, biochemical and histological profiles: immune-tolerant (IT) [HBeAg-positive, very high serum level of HBV DNA, normal serum alanine aminotransferase (ALT) level without significant liver necroinflammation activity and fibrosis], immune-reactive (HBeAg-positive, high HBV DNA and ALT levels with moderate to severe liver activity and fibrosis) and the inactive carrier state, which follows HBeAg seroconversion and reflects host immune control of the HBV infection (HBeAg-negative, low HBV DNA level, normal ALT level without liver damage in most cases). An HBeAg-negative chronic hepatitis B (CHB) phase (HBeAg-negative, HBV DNA level above 2,000–20,000 IU/mL, normal/high ALT level and histological signs of CHB) occurs in patients who have achieved HBeAg seroconversion or in inactive carriers due to HBV reactivation [1]. Basal core promoter (BCP) mutations have been reported to possibly modulate HBV replication [2–4] and could thus impact the natural course of CHB. In addition, BCP mutations (the more common are the BCP A1762T/G1764A dual mutations) and precore G1896A mutation lead to the impairment and abolishment, respectively, of HBeAg production [5], and they have been reported in patients with HBeAg-negative CHB occurring under immune pressure to control HBV infection. Importantly, the more common BCP dual mutations have been shown to increase the risk of developing hepatocellular carcinoma (HCC) [6, 7]. Turyadi et al. [8] carried out a cross-sectional study to characterize the relationships between viral factors and the natural history of CHB within the Indonesian population. In their study, Turyadi et al. assessed the correlations between viral parameters [serum HBsAg, HBeAg and HBV DNA levels, HBV genotype and BCP (A1762T/G1764A)/ precore (G1896A) mutations] in different stages of HBV infection within a cohort of 152 treatment-naive Indonesian patients. Patients were categorized into the four phases of CHB, denoted IT, immune-clearance (IC, i.e, immunereactive phase), low/non-replicative (LR, i.e., inactive carrier state) and HBeAg-negative CHB (ENH). The authors showed that HBsAg and HBV DNA serum levels were both at a high level and strongly correlated in the early phases of CHB (i.e., IT and IC), but a tendency to separate from one another occurred after HBeAg seroconversion. A moderate correlation between serum HBV DNA and serum HBsAg titers was found in the ENH phase, and no correlation was observed in the LR phase. These important results are consistent with previous studies [9, 10] and suggest that the control of HBV replication by the immune system does not hamper HBsAg production. In this study, a temporal relationship between HBeAg seroconversion and an increase of prevalence of patients with This is an editorial to the article available at doi:10.1007/s12072-0139438-z

Occult and Overt HBV Co-Infections Independently Predict Postoperative Prognosis in HCV-Associated Hepatocellular Carcinoma

Objective and BackgroundThe roles of chronic hepatitis B virus (HBV) co-infection (CI) in carcinogenesis of hepatitis C virus (HCV)-associated hepatocellular carcinoma (HCC) remained controversial. To gain new insights into this issue, we investigated the postoperative prognostic value of HBVCI in HCV-associated HCC.MethodsA study cohort of 115 liver tissues obtained from the noncancerous parts of surgically removed HCV-associated HCCs were subjected to virological analysis in a tertiary care setting. Assayed factors included clinicopathological variables, tissue amounts of viral genomes, genotypic characterization of viruses, as well as the presence of overt (serum HBsAg positive) or occult (serum HBsAg negative but tissue HBV-DNA positive) HBVCI. Cox proportional hazard model was used to estimate postoperative survivals.ResultsOf the 115 patients, overt and occult HBVCIs were detected in 35 and 16 patients, respectively. Multivariate analysis revealed that tumor size >3 cm (adjusted hazard ratio (AHR), 2.079 [95% confidence interval, 1.149∼3.761]), alpha-fetoprotein >8 ng/mL (AHR, 5.976 [2.007∼17.794]) albumin <4 g/dL(AHR, 2.539 [1.399∼4.606]), ALT >50 U/L (AHR,1.086 [1.006∼1.172]), presence of occult HBVCI (AHR, 2.708 [1.317∼5.566]), and absence of overt HBVCI (AHR, 2.216 [1.15∼4.269]) were independently associated with unfavorable disease-free survival. Patients with occult HBVCI had a shorter disease-free (P = 0.002), a shorter overall survival (P = 0.026), a higher bilirubin level (P = 0.003) and a higher prevalence of precore G1896A mutation (P = 0.006) compared with those with overt HBVCI.ConclusionOccult and overt HBVCI served as independent predictors for postoperative survival in HCV-associated HCC.

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

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. 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. 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. 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.

Effects of hepatitis B virus mutations on its replication and liver disease severity.

Hepatitis B virus (HBV), nowadays, is one of the major human pathogens worldwide. Approximately, 400 million people worldwide have chronic HBV infection. Only 5% of persons infected during adulthood develop chronic infection. The reverse is true for those infected at birth or in early childhood, i.e. more than 90% of these persons progress to chronic infection. Currently, eight different genotypes o f HBV have been identified, differing in nucleotide sequence by greater than 8%. In addition, numerous subgenotypes have a l s o been recognized based on the nucleotide sequence variability of 4- 8%. It has invariably been found that these genotypes and mutations play a pivotal role in the liver disease aggravation and virus replication. The precore mutations (G1896A) and the double mutation (T1762/A1764) in the basal core promoter are important mutations that alter expression of the hepatitis B e antigen (HBeAg). The HBeAg is important for establishing viral persistence. The precore G1896A mutation abrogates the expression of HBeAg. Numerous other mutations alter the disease severity and progression. It is predictive that the infected patient has high risk of hepatocellular carcinoma if the genotype C is incriminated or if HBV possesses basal core promoter double mutation. Association of the remaining genotypes have been noted but with less degree than genotype C. Phenotypic assays of the different HBV protein markers with different molecular techniques illustrate the replication efficiency of the virus in cell lines. This review will discuss various mutations into their association with liver disease severity and progression as well as virus replication.

The Possible Role of TLR2 in Chronic Hepatitis B Patients with Precore Mutation

Recognition mechanisms of innate immune response help to improve immunotherapeutic strategies in HBeAg-negative chronic hepatitis B (CHB). Toll-like receptor 2 (TLR2) is an important component of innate immunity. In this study, the frequency of precore mutations of the hepatitis B virus (HBV) and serum TLR2 were evaluated in CHB patients. Fifty-one patients with chronic hepatitis B, negative for HBeAg and detectable HBV DNA, were examined for the presence of mutations in pre-core region of HBV genome by direct sequencing. Serum TLR2 was measured by enzyme-linked immunosorbent assay. Interactions of truncated HBeAg and TLR2 proteins were evaluated with molecular docking software. The G1896A pre-core mutation were detected in 29 (57%) which was significantly associated with higher concentration of serum TLR2 in comparison with patients without this mutation (4.8 ± 2.9 versus 3.4 ± 2.2 ng/mL, P = 0.03). There was also a significant correlation between serum ALT and TLR-2 (r = 0.46; P = 0.01). Docking results illustrated residues within the N-terminus of truncated HBeAg and TLR2, which might facilitate the interaction of these proteins. These findings showed the dominance of G1896A pre-core mutation of HBV variants in this community which was correlated with serum TLR2. Moreover TLR2 is critical for induction of inflammatory cytokines and therefore ALT elevation.

Investigation of DNA Sequence in the Basal Core Promoter, Precore, and Core Regions of Hepatitis B Virus from Tunisia Shows a Shift in Genotype Prevalence

BackgroundIn this study, we evaluated the prevalence of the most common mutations occurring in Enhancer II (EnhII), Basal Core Promoter (BCP), Precore (PC), and Core (C) regions of hepatitis B virus (HBV) genome.ObjectivesWe also investigated the correlation between HBV variants, their genotypes, and patients’ HBe antigen (HBeAg: soluble shape of the capsid antigen) status.Patients and MethodsWe retrieved viral DNA from 40 serum samples of Tunisian patients positive for hepatitis B surface antigen (HBsAg) and HBV DNA, amplified the above mentioned regions using specific primers, and sequenced the corresponding PCR (polymerase chain reaction) products. For further analysis purpose, the patients were divided into two groups: Group1 including 34 HBeAg-negative patients and Group2 with 6 HBeAg-positive patients.ResultsTwenty-one patients (52.5%) showed PC G1896A mutation and 11 (27.5%) carried A1762T/G1764A double mutations. These mutations were more frequent in HBeAg-negative patients than that in HBeAg-positive ones. Indeed, 58.8% of patients bearing G1896A mutation were HBeAg-negative while 16.7% were positive. In patients bearing T1762/A1764 double mutation, 29.4% were positive and 16.7% were negative. In addition, the A1896 mutation was restricted to HBV isolates that had wild-type T1858, while C1858 was rather linked to the occurrence of T1762/A1764 mutation. Interestingly, this study revealed a high frequency of genotype E. This frequency was important as compared to that of genotype D known to be predominant in the country as delineated in previous studies.ConclusionsPrevious results supported and showed that HBV strains present in Tunisia belonging to genotype D and, to a lesser extent, to genotype E, were prone to mutations in BCP/ PC regions. This observation was more obvious in HBV isolates from asymptomatic chronic carriers (AsC). The high mutational rates observed in our study might result from a mechanism of viral escape that plays an important role in the loss of HBeAg.

Hepatitis B virus basal core promoter mutations A1762T/G1764A are associated with genotype C and a low serum HBsAg level in chronically-infected HBeAg-positive Chinese patients

The present study was aimed to obtain baseline information of basal core promoter A1762T/G1764A and precore G1896A mutations of hepatitis B virus (HBV) in 192 HBeAg-positive chronically-infected Chinese patients, who were potential candidates for antiviral treatment. The detection of these mutations (including minor mutant subpopulations) was achieved by direct sequencing, whose sensitivity for minor mutant subpopulations identification was confirmed by clone sequencing. Patients enrolled were infected with either genotype B (46.35%) or C (53.65%) HBV identified by routine tests in our laboratory. The A1762T/G1764A or G1896A mutations were detected in 125specimens (125/192, 65.10%), in which 77 (77/125, 61.60%) existed as subpopulations. The A1762T/G1764A mutations were found to be more prevalent in genotype C than that in genotype B HBV [62.14% (64/103) vs. 20.22% (18/89), P<0.0001]. There is no statistically significant link between G1896A and genotypes. The emergence of A1762T/G1764A mutations was also found to be associated with an older age, an elevated ALT/AST level, and a lower HBsAg level in serum [wild-type vs. mutant: 4.57 (3.46–5.42) vs. 3.93 (2.51–5.36), P<0.0001]. In conclusion, HBV basal core promoter mutations A1762T/G1764A are associated with genotype C and a low serum HBsAg level in chronically-infected HBeAg-positive Chinese patients.

Fatal fulminant primary hepatitis B virus infections with G1896A precore viral mutants in southeastern France

Fulminant hepatitis has been shown to occur in about 1% of acute hepatitis B virus (HBV) infections, and its mortality rate is nearly 70%. Specific HBV genotypic features have been pointed out in fulminant acute hepatitis B worldwide, but these associations remain controversial. We describe all four primary HBV infections diagnosed in 2008 in our institution in Marseille, southeastern France, including two fatal cases. HBV genotypes were D or E. Precore G1896A HBV mutants were detected in both fatal fulminant primary HBV infections. Hepatitis B surface antigen and hepatitis B e antigen (HBeAg) were negative in two and three cases, respectively, despite HBV DNA detection. Primary HBV infection remains a cause of death in France. The impact of the precore G1896A mutation on the severity of AHB deserves to be assessed in larger studies in this country.

Quantification of complex precore mutations of hepatitis B virus by SimpleProbe real time PCR and dual melting analysis

Background Hepatitis B virus (HBV) precore G1896A mutation is associated with Hepatitis B e antigen (HBeAg) seroconversion. This mutation and the adjacent G1899A mutation also appear to associate with increased risk of hepatocellular carcinoma. Quantitative mutant dynamics may help determine the potential of these mutants as clinical biomarkers. However, a reliable method to quantify either mutant is not available, partly because the viral genome has polymorphisms in general and the precore mutations are complex. Objectives (1) To develop a reliable and ultrasensitive assay for the quantification of HBV G1896A and/or G1899A mutants. (2) To obtain preliminary data on the quantities of the precore mutants in patients. Study design A SimpleProbe real time PCR assay was developed to quantify the HBV precore mutants. Dual melting analysis and a primer-probe partial overlap approach were used to increase detection accuracy. A wild-type selective PCR blocker was also developed to increase mutant detection sensitivity. Results The assay correctly identified the precore sequence from all 62 patient samples analyzed. More than 97% of precore sequences in the GenBank can be recognized. Mutant detection sensitivity reached 0.001% using a wild type-selective PCR blocker. At least one precore mutant can be detected from all 20 HBeAg-positive individuals who were negative for precore mutations by DNA sequencing. Conclusions The reliability of this ultrasensitive mutation quantification assay was demonstrated. The same approaches may be useful for the detection of other clinically significant mutations. Evolution of the precore mutants warrants further studies.

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.

Downregulation of HLA Class II Molecules by G1896A Pre-Core Mutation in Chronic Hepatitis B Virus Infection

Over the past decade, increasing attention has been focused on the contribution of naturally occurring mutations in the hepatitis B virus (HBV) genome to the clinical course of the chronic infection. The aim of this study was to investigate the effect of the HBV pre-core mutation G1896A on the expression of HLA class II molecules and the core protein of hepatitis B in liver biopsies of chronic hepatitis B (CHB) infection. In 30 HBeAg-negative CHB patients the pre-core region of the HBV genome was amplified and sequenced to determine the presence of the mutation G1896A. Liver biopsies were scored based on the Histology Activity Index (HAI) system and immunohistochemistry (IHC) was performed to study the expression of HLA class II molecules on the antigen-presenting cells and the core protein in hepatocytes. We found that 19 of the 30 patients (63%) harbored the G1896A mutation. Compared to the patients without this mutation, those with G1896A had lower HAI scores (5.0 +/- 2.8 versus 7.9 +/- 4, p = 0.03). The study of the expression of HLA-II molecules in our patients revealed that subjects with the G1896A mutation had lower expression of HLA-II compared to wild-type infected subjects (1.87 +/- 0.6 versus 3.27 +/- 1.5, p < 0.01). Core protein expression was present in four patients (13.3%) who had higher HBV DNA levels than patients without core protein expression (3.81 +/- 0.78 versus 2.02 +/- 0.16, p < 0.001). These results suggest that the G1896A pre-core mutation may directly interfere with antigen presentation, most likely by decreasing the availability of HLA class II molecules, and this may result in less aggressive liver disease in HBeAg-negative CHB infection.

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.

Association of core promoter/precore mutations and viral load in e antigen‐negative chronic hepatitis B patients

Apart from core promoter A1762T/G1764A and precore G1896A mutations, other hepatitis B virus (HBV) mutants are detected in hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB). The aim of this study was to determine the effects of those mutants on clinical manifestation and viral loads of genotypes B and C HBV. Seventy-nine HBeAg-negative CHB patients with hepatitis flare were enrolled in this study and their HBV precore/core region were sequenced. Serial biochemical profiles and viral loads were assessed and compared. Fifty-three patients (67%) were infected by genotype B HBV and 26 (33%) were infected by genotype C HBV. The clinical manifestation and HBV viral loads were comparable between the two groups. However, genotype B was significantly associated with precore G1896A mutation (92.5%), and more mutations within nucleotide 1809-1817 were detected in patients infected by genotype B as compared with those infected by genotype C (18.9%vs 3.8%). Most of the cases had mutations at the -2, -3 or -5 position from the precore AUG initiation codon. Triple core promoter mutations T1753C/A1762T/G1764A [corrected] appeared to be linked to genotype C rather than genotype B HBV (19.2%vs 1.9%; P = 0.013). In multivariate analysis, the presence of either triple core promoter 1753/1762/1764 mutation or nucleotide 1809-1817 mutation was the only factor associated with lower HBV viral load (<70 Meq/mL) (odds ratio = 9.01; 95% CI 1.11-71.43; P = 0.04). In conclusion, minor HBV variants with mutations in the core promoter and precore region were detectable in genotypes B and C. Such HBV variants are genotype specific and related to viraemia levels.

Hepatitis B virus genotypes and G1896A precore mutation in 486 Spanish patients with acute and chronic HBV infection

This study aims to determine the prevalence of hepatitis B virus (HBV) genotypes (A-F) and their association with the G1896A precore mutation in 486 patients positive for HBV surface antigen. Genotypes were determined by RFLP and precore mutation by real-time PCR. Genotypes D (48.1%) and A (39.5%) were the most common, followed by F (4.1%) and B, C and E (<1%). The A to D ratio (A:D) was 1.4 in HBeAg+ chronic hepatitis B (CHB), 0.6 in HBeAg- CHB and 1.4 in HBeAg- inactive carriers. Distribution of these genotypes was different between HBeAg+ CHB and HBeAg- CHB (P = 0.02), and between HBeAg- CHB and HBeAg- inactive carriers (P = 0.009). Genotype A was the most prevalent in HBeAg+ CHB with elevated alanine aminotransferase (ALT) (68.6%) and genotype D in HBeAg+ CHB with fluctuating ALT (60.7%). There was a difference in genotype prevalence between chronic and acute infection (P = 0.03). The precore mutant correlated with high levels of HBV-DNA in genotype d HBeAg- CHB. Genotype D is not as highly prevalent in Spanish patients as would be expected in a Mediterranean area. The unequal prevalence of genotypes between acute and chronic infection suggests that genotype A is associated with a higher tendency to cause chronic infection.