Hepatitis B virus carriers without precore mutations in hepatitis B e antigen-negative stage show more severe liver damage

Hepatitis B virus sequencing and liver fibrosis evaluation in HIV/HBV co-infected Nigerians

OBJECTIVES

Molecular characteristics of hepatitis B virus (HBV), such as genotype and genomic mutations, may contribute to liver-related morbidity and mortality. The association of these characteristics with liver fibrosis severity in sub-Saharan Africa is uncertain. We aimed to characterise molecular HBV features in human immunodeficiency virus (HIV)/HBV co-infected Nigerians and evaluate associations between these characteristics and liver fibrosis severity before and after antiretroviral therapy (ART) initiation.

METHODS

HIV/HBV co-infected Nigerians underwent liver fibrosis estimation by transient elastography (TE) prior to and 36 months after ART initiation. Basal core promoter/precore (BCP/PC) and preS1/preS2/S regions of HBV were sequenced from baseline plasma samples. We evaluated associations between HBV mutations and liver fibrosis severity by univariate and multivariable regression.

RESULTS

At baseline, 94 patients underwent TE with median liver stiffness of 6.4 (IQR 4.7-8.7) kPa. Patients were predominantly infected with HBV genotype E (45/46) and HBe-antigen negative (75/94, 79.8%). We identified BCP A1762T/G1764A in 15/35 (43%), PC G1896A in 20/35 (57%), 'a' determinant mutations in 12/45 (26.7%) and preS2 deletions in 6/16 (37.5%). PreS2 mutations were associated with advanced fibrosis in multivariable analysis. At follow-up, median liver stiffness was 5.2 (IQR 4.1-6.6) kPa. No HBV molecular characteristics were associated with lack of fibrosis regression, although HIV virologic control, body mass index (BMI) and baseline CD4+ T-cell count were associated with a decline in fibrosis stage.

CONCLUSION

Frequent BCP/PC and preS1/preS2/S mutations were found in ART-naïve HIV/HBV co-infected Nigerians. Median liver stiffness declined after initiation of ART, regardless of pre-ART HBV mutational pattern or virologic characteristics.

High association of T1858-G1896 precore mutations with impaired base pairing and high hepatitis B virus DNA levels in HBeAg-negative chronically infected patients

The progression of liver disease in hepatitis B virus (HBV) infection is fostered by active virus replication. Mutations in the basal core promoter (BCP) and precore (PC) regions of the HBV genome are known to have an impact on viral replication. The aim of the present study was to assess the correlation of mutation profiles in the BCP and PC regions with the viral load in HBeAg-negative chronically infected patients. The HBV genotype, BCP/PC mutations, serum HBV DNA levels, and associated serological markers were analyzed in 92 HBeAg-negative chronically infected patients. Sequence analysis of the BCP and PC regions revealed variability of 19% and 24.1%, respectively. This variability was primarily associated with five critical positions (1753, 1762, 1764, 1896 and 1899). An elevated HBV viral load (>20,000 IU/ml) was classically correlated with F2-F4 liver fibrosis, elevated serum alanine aminotransferase levels, 1762/1764 and 1753 combination mutations, and surprisingly, with an 1858T-1896G double mutation that impairs base pairing at the base of the bulge in the ε encapsidation signal. An analysis of covariance confirmed the independent nature of the relationship between the 1858T-1896G double mutation and the HBV viral load. In conclusion, independently of conventional parameters, this study demonstrates that a high serum HBV DNA level was also associated with PC 1858-1896 mutations. These BCP/PC mutations may have important clinical implications as predictive factors for HBV DNA increase.

Impact of HBV genotypes A and D genetic variability on infection evolution

HBV is characterized by a high genetic variability, which is the basis of its classification into eight genotypes (A-H). HBV infection is associated with different outcomes, from self-limiting acute hepatitis to active chronic hepatitis, asymptomatic carriage, and occult infection. The aim of this study was to analyze the genetic variability of HBV genotypes A and D isolates from 79 cases of self-limiting acute hepatitis and chronic hepatitis, in order to identify HBV variants associated with resolution or chronicity of acute HBV infection. The entire preS-S sequence and a fragment of 346 bp of the preC-C region, containing Enhancer II and Basal Core Promoter sequences, were analyzed. A phylogenetic analysis of preS/S region showed that the 45.45% (15/33) of isolates from acute hepatitis cases were genotype A compared to 8.69% (4/46) of chronic hepatitis cases. (p = 0.0002). Mutations associated with immune-escape (T131N, D144A/E, G145K), amino acid polymorphisms in "a determinant" domain of S protein and mutations/deletions in preC/C region were found in isolates from acute and chronic hepatitis B cases. In this study mutations/deletions in preS-S and preC-C regions, usually associated with fulminant acute hepatitis, advanced forms of liver disease and increased risk for HCC, were identified in HBV strains of genotype A and D obtained both from patients with self-limiting acute HBV infection and from persistent infected patients. This founding probably is due to the natural viral evolution under host immune response and to the circulation of a wide variety of HBV strains in our geographic area because of the ancient introduction of genotype D and the migrant fluxes from North Africa. Moreover, the analysis of circulation of new HBV antigenic variants is fundamental for the epidemiological surveys and for the evaluation of the impact of viral evolution on vaccine prophylaxis strategies.

Variability in the precore and core promoter regions of HBV strains in Morocco: characterization and impact on liver disease progression

Background

Hepatitis B virus (HBV) is one of the most common human pathogens that cause aggressive hepatitis and advanced liver disease (AdLD), including liver cirrhosis and Hepatocellular Carcinoma. The persistence of active HBV replication and liver damage after the loss of hepatitis B e antigen (HBeAg) has been frequently associated with mutations in the pre-core (pre-C) and core promoter (CP) regions of HBV genome that abolish or reduce HBeAg expression. The purpose of this study was to assess the prevalence of pre-C and CP mutations and their impact on the subsequent course of liver disease in Morocco.

Methods/Principal Findings

A cohort of 186 patients with HBeAg-negative chronic HBV infection was studied (81 inactive carriers, 69 with active chronic hepatitis, 36 with AdLD). Pre-C and CP mutations were analyzed by PCR-direct sequencing method. The pre-C stop codon G1896A mutation was the most frequent (83.9%) and was associated with a lower risk of AdLD development (OR, 0.4; 95% CI, 0.15–1.04; p = 0.04). HBV-DNA levels in patients with G1896A were not significantly different from the other patients carrying wild-type strains (p = 0.84). CP mutations C1653T, T1753V, A1762T/G1764A, and C1766T/T1768A were associated with higher HBV-DNA level and increased liver disease severity. Multiple logistic regression analysis showed that older age (≥40 years), male sex, high viral load (>4.3 log₁₀ IU/mL) and CP mutations C1653T, T1753V, A1762T/G1764A, and C1766T/T1768A were independent risk factors for AdLD development. Combination of these mutations was significantly associated with AdLD (OR, 7.52; 95% CI, 4.8–8; p<0.0001).

Conclusions

This study shows for the first time the association of HBV viral load and CP mutations with the severity of liver disease in Moroccan HBV chronic carriers. The examination of CP mutations alone or in combination could be helpful for prediction of the clinical outcome.

Number of mutations within CTL-defined epitopes of the hepatitis B Virus (HBV) core region is associated with HBV disease progression

The virologic determinants of progressive liver disease associated with hepatitis B virus (HBV) remain unclear. Previous investigations have associated HBV disease with specific mutations but this association may be confounded by HBV genotype, HLA haplotype of the infected individual or both. The association between non-synonymous mutations located within putative cytotoxic T-lymphocyte directed epitopes (CDE) of the HBV core region and disease states was investigated. Subjects infected with HBV were enrolled from a clinical cohort in Seoul, Korea, and HBV core gene sequences were analyzed for mutational patterns inside and outside of CDE with respect to subject demographics and HBV-related disease states. No specific mutation or pattern of mutations were associated with progressive disease states; however, individuals with cirrhosis and hepatocellular carcinoma had greater numbers of non-synonymous mutations within CDE when compared to those with chronic HBV infection who were HBeAg positive (P = 0.007 and 0.026, respectively). In conclusion, this study demonstrates that HBV disease progression is associated with viral escape mutations that are a marker of CTL activity. These data suggest that the number of non-synonymous mutations in the HBV core region may predict HBV disease progression better than any single mutation or pattern of mutations.

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.

An outbreak of hepatitis B with high mortality in India: association with precore, basal core promoter mutants and improperly sterilized syringes

In 2009, an outbreak of hepatitis B with high mortality was observed in Sabarkantha district, Gujarat state, India with 456 cases and 89 deaths. Hospitalized patients with self-limiting disease (152, AVH)) and fulminant hepatic failure (39, FHF including 27 fatal and 12 survivals) were investigated. These were screened for diagnostic markers for hepatitis viruses, hepatitis B virus (HBV) genotyping and mutant analysis. Complete HBV genomes from 22 FHF and 17 AVH cases were sequenced. Serosurveys were carried out in the most and least affected blocks for the prevalence of HBV and identification of mutants. History of injection from a physician was associated with FHF and AVH cases. Co-infection with other hepatitis viruses or higher HBV DNA load was not responsible for mortality. Four blocks contributed to 85.7% (391/456) of the cases and 95.5% (85/89) mortality while two adjacent blocks had negligible mortality. Sequence analysis showed the presence of pre-core and basal core promoter mutants and 4 amino acid substitutions exclusively among FHF cases. None of the self-limiting patients exhibited these dual mutations. Genotype D was predominant, D1 being present in all FHF cases while D2 was most prevalent in AVH cases. Probably due to violation of accepted infection control procedures by the qualified medical practitioners, HBV prevalence was higher in the affected blocks before the outbreak. Gross and continued use of HBV contaminated (mutant and wild viruses) injection devices led to an explosive outbreak with high mortality with a striking association with pre-C/BCP mutants and D1 genotype.

Spontaneous increases in alanine aminotransferase levels in asymptomatic chronic hepatitis B virus-infected patients

BACKGROUND & AIMS

No information is available about the frequency or factors that predict spontaneous increases in alanine aminotransferase (ALT) levels in asymptomatic Indian patients with chronic hepatitis B virus (HBV) infection who are HB e antigen (HBeAg) negative and have normal ALT levels.

METHODS

We followed 217 asymptomatic patients with chronic HBV who were HBeAg negative, anti-HBe antigen (anti-HBe) positive, and had normal ALT levels. Spontaneous increases in ALT levels (ALT flares) were considered to be >2-fold the upper limit of normal (ULN) and were accompanied by HBV DNA levels>or=10(5) copies/mL or a 100-fold increase from the previously measured level.

RESULTS

During a median follow-up period of 69.0 months, spontaneous ALT flares occurred in 43 patients (an annual rate of 4.3%), with cumulative probabilities of 10.8% and 47.3% after 5 and 10 years, respectively. Based on multinomial logistic regression, the probability of an ALT flare correlated with age>or=30 years at presentation (odds ratio [OR], 5.31; 95% confidence interval [CI]: 1.53-18.39; P=.008), male sex (OR, 4.54; 95% CI: 1.01-20.76; P=.05), and presence of a precore mutation (OR, 10.99; 95% CI: 3.67-32.92; P<.001). The median time to spontaneous ALT flare after enrollment was 25 months (range, 1-128 months; 10th percentile=3.4 months).

CONCLUSIONS

In asymptomatic patients with chronic HBV infection who have normal ALT levels and are HBeAg negative, the annual rate of ALT flares was 4.3%. Precore mutants, male sex, and age>or=30 years at presentation are independent predictors for an ALT flare. A follow-up every 3 months can capture up to 90% of flares and would help identify patients who require antiviral therapy.

Associations between hepatitis B virus genotype and mutants and the risk of hepatocellular carcinoma

Background

The risk of hepatocellular carcinoma (HCC) increases with increasing level of hepatitis B virus (HBV) in serum (viral load). However, it is unclear whether genetic characteristics of HBV, including HBV genotype and specific genetic mutations, contribute to the risk of HCC. We examined the HCC risk associated with HBV genotypes and common variants in the precore and basal core promoter (BCP) regions.

Methods

From January 5, 1991, to December 21, 1992, baseline blood samples were collected from 2762 Taiwanese men and women who were seropositive for HBV surface antigen but had not been diagnosed with HCC; the samples were tested for HBV viral load by real-time polymerase chain reaction and genotyped by melting curve analysis. Participants who had a baseline serum HBV DNA level greater than 10⁴ copies/mL (n = 1526) were tested for the precore G1896A and BCP A1762T/G1764A mutants by direct sequencing. Incident cases of HCC were ascertained through follow-up examinations and computerized linkage to the National Cancer Registry and death certification profiles. A Cox proportional hazards model was used to estimate the risk of HCC associated with HBV genotype and precore and BCP mutants after adjustment for other risk factors. All statistical tests were two-sided.

Results

A total of 153 HCC cases occurred during 33 847 person-years of follow-up. The HCC incidence rates per 100 000 person-years for participants infected with HBV genotype B or C were 305.6 (95% confidence interval [CI] = 236.9 to 388.1) and 785.8 (95% CI = 626.8 to 972.9), respectively. Among participants with a baseline HBV DNA level of at least 10⁴ copies/mL, HCC incidence per 100 000 person-years was higher for those with the precore G1896 (wild-type) variant than for those with the G1896A variant (955.5 [95% CI = 749.0 to 1201.4] vs 269.4 [95% CI = 172.6 to 400.9]) and for those with the BCP A1762T/G1764A double mutant than for those with BCP A1762/G1764 (wild-type) variant (1149.2 [95% CI = 872.6 to 1485.6] vs 358.7 [95% CI = 255.1 to 490.4]). The multivariable-adjusted hazard ratio of developing HCC was 1.76 (95% CI = 1.19 to 2.61) for genotype C vs genotype B, 0.34 (95% CI = 0.21 to 0.57) for precore G1896A vs wild type, and 1.73 (95% CI = 1.13 to 2.67) for BCP A1762T/G1764A vs wild type. Risk was highest among participants infected with genotype C HBV and wild type for the precore 1896 variant and mutant for the BCP 1762/1764 variant (adjusted hazard ratio = 2.99, 95% CI = 1.57 to 5.70, P < .001).

Conclusions

HBV genotype C and specific alleles of BCP and precore were associated with risk of HCC. These associations were independent of serum HBV DNA level.

Role of genotype and precore/basal core promoter mutations of hepatitis B virus in patients with chronic hepatitis B with acute exacerbation

OBJECTIVE

The results of long-term, follow-up studies show that the severity and frequency of acute exacerbation of chronic hepatitis B virus (HBV) are associated with the development of liver cirrhosis in chronic HBV infection. The aim of this study was to investigate the relationship between virological factors of HBV and the severity of acute exacerbation.

MATERIAL AND METHODS

Fifty-one chronic hepatitis B patients with symptomatic acute exacerbation without antiviral therapy were enrolled in the study. Genotype of HBV was determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Precore (A1896) and basal core promoter (BCP) mutations (T1762 & A1764) were determined by PCR and direct sequencing.

RESULTS

Thirty-nine patients had genotype B, 11 patients had genotype C, and 1 patient had an unclassified genotype. Thirty-two patients had precore mutation and 24 patients had BCP mutation. After adjusting for age, gender, aspartate aminotransferase (ASAT) level, albumin level, and platelet count by multiple logistic regression test, precore mutation had a protective effect on the occurrence of hepatic decompensation (p=0.046), and genotype and BCP mutations were not associated with the occurrence of hepatic decompensation.

CONCLUSIONS

HBV precore mutation may confer less severe liver disease during acute exacerbation of chronic HBV. Genotype and BCP mutations did not have a significant association with the occurrence of hepatic decompensation.

Virologic and histologic features of chronic hepatitis B virus-infected asymptomatic patients with persistently normal ALT

BACKGROUND & AIMS

There is a paucity of data on hepatitis B virus (HBV) DNA levels and histologic lesions in patients with chronic HBV (CHBV) infection and persistently normal alanine aminotransferase (ALT) levels (PNALT). We studied the ALT, HBV DNA levels, and spectrum of histologic lesions in such patients.

METHODS

One thousand three hundred eighty-seven incidentally detected asymptomatic hepatitis B surface antigen (HBsAg)-positive patients with >/=1-year follow-up and either PNALT (n = 189; hepatitis B e antigen [HBeAg(+)], 73; HBeAg(-), 116) or persistently or intermittently elevated ALT (PIEALT; n = 1198; HBeAg(+), 530; HBeAg(-), 668) were included.

RESULTS

In the PIEALT and PNALT patients, baseline DNA >/=5-log copies/mL was seen in 73.8% and 60.3% in HBeAg(+) (P = .018) and 76% and 35.3% in HBeAg(-) (P < .001) patients and histologic fibrosis stage >/=2 in 65.5% and 40.2% in HBeAg(+) (P < .001) and 63.9% and 13.8% in HBeAg(-) (P < .001) patients, respectively. Approximately 21% of HBeAg(-) patients with PNALT and HBV DNA <5-log copies/mL had histologically active liver disease (histologic activity index >/=3 and/or fibrosis stage >/=2).

CONCLUSIONS

A fair proportion of patients with CHBV infection with PNALT have HBV DNA >/=5-log copies/mL and significant histologic fibrosis. Use of ALT and HBV DNA levels without resorting to liver biopsy to define "inactive carrier state" in HBeAg(-) PNALT patients may miss histologically significant disease in a proportion of patients.

Clinical and virological characteristics of hepatitis B virus subgenotypes Ba, C1, and C2 in China

Hepatitis B virus (HBV) subgenotypes Ba, C1 (Cs), and C2 (Ce) are the most prevalent HBV variants in China. To investigate the virological characteristics of these subgenotypes and their clinical implications, we enrolled a cohort of 211 patients in the Guangdong Province of China, including 132 with chronic hepatitis B virus infection (CH), 32 with liver cirrhosis (LC), and 47 with hepatocellular carcinoma (HCC) according to clinical examination, liver function test, and ultrasonograph results. Overall, HBV Ba was found in 51.2% (108/211), HBV C1 in 33.6% (71/211), and HBV C2 in 15.2% (32/211) of the cases. The distribution of HBV genotype C was greater among patients in the LC and HCC groups than among patients in the CH group, while the distribution of HBV genotype B was greater among the CH patients than among the LC and HCC patients. No significant differences in clinical features were found among patients with HBV Ba, C1, and C2. Virologically, HBV C1 had the strongest association with the A1762T G1764A double mutation, while the mutation at position 1896 resulting in A (1896A) was uncommon. In contrast, HBV Ba had the highest frequency of 1896A but the lowest of A1762T G1764A, and HBV C2 had intermediate frequencies of these mutations. Mutations of 1653T and 1753V were specifically associated with HBV C2 and C1, respectively. Multivariate analyses showed that the 1653T, 1753V, and A1762T G1764A mutations and patient age significantly increased the risk of HCC development. In conclusion, HBV Ba, C1, and C2 have different mutation patterns in the enhancer II/core promoter/precore region. Therefore, genotyping and detecting the 1653T and 1753V mutations, in addition to the A1762T G1764A double mutation, might have important clinical implications as predictive risk factors for hepatocarcinogenesis.

Long-term results of interferon alpha monotherapy in patients with HBeAg-negative chronic hepatitis B

We sought to evaluate the long-term results of interferon-alpha (IFN-alpha) therapy in patients with hepatitis B e antigen (HBeAg)-negative chronic hepatitis B. Eighty HBeAg-negative naive patients (62 men; mean age, 39.9 years) who received IFN-alpha for 6 months were studied. Alanine aminotransferase normalization with undetectable HBV-DNA by molecular hybridization was accepted as response. All patients but 1 were precirrhotic stage. At the end of treatment, 44 (55%) patients responded, and they were followed for a mean of 59.5 months (range, 18-132). Twenty-seven patients (61.4%) showed recurrence (63% in first year). Responses at 6 months and at the end of the follow-up period 42.5% and 30% (including 7 patients without end treatment response), respectively. Recurrence of HBV replication was not detected after the 2-years follow-up period. Histologic improvement was observed in 83.3% patients with end-of-follow-up response. HBsAg became negative in 4 patients (5%). On multivariate analysis, younger age (P = .04) and lower GGT level (P = .037) were independent factors for prediction of end-of-follow-up response. Nearly half of the patients with HBeAg-negative chronic hepatitis B responds to IFN-alpha at the end of therapy. Despite the high recurrence rates, response continues in about one third of patients after a mean of 59.5 months.

Hepatitis B genotypes: relation to clinical outcome in patients with chronic hepatitis B in Saudi Arabia

AIM

To identify the most common hepatitis B virus (HBV) genotype in Saudi Arabia, and correlate the prevailing genotypes with the clinical outcome of patients.

METHODS

Patients were consecutively recruited from the hepatology clinics of two tertiary care referral centers. Patients were categorized into 4 different groups: group 1, patients with hepatitis B and normal liver enzymes; group 2, patients with hepatitis B and abnormal liver enzymes but without cirrhosis; group 3, patients with hepatitis B and liver cirrhosis; group 4, patients with hepatitis B and hepatocellular carcinoma. All patients had a positive hepatitis B surface antigen (HBsAg). Genotyping of HBV was performed by nested PCR-mediated amplification of the target sequence and hybridization with sequence-specific oligonucleotides.

RESULTS

Seventy patients were enrolled in this study. They were predominantly male (72.9%) in their mid-forty's (mean age 47 years). Forty-nine (70%) patients were hepatitis B envelope antigen (HBeAg) negative. The majority of patients (64%) acquired HBV through unknown risk factors. Hepatitis B genotyping revealed that 57 patients (81.4%) were genotype D, 1 patient (1.4%) had genotype A, 1 patient (1.4%) had genotype C, and 4 patients (5.7%) had genotype E, while 7 patients (10%) had mixed genotype (4 patients ADG, 1 patient DE, 1 patient DF, and 1 patient ADFG). Based on univariate analysis of genotype D patients, significant predictors of advanced liver disease were age, gender, aspartate transaminase, alanine transaminase, albumin, bilirubin, and alkaline phosphatase (all P < 0.001). In multivariate analysis decreased hemoglobin (r = -0.05; 95% CI: -0.08 to -0.03; P = 0.001) and albumin levels (r = -0.004; 95% CI: -0.007 to -0.001; P = 0.002) were highly significant predictors of advanced liver disease. In patients with HBV genotype D, HBeAg negativity was found to increase across advancing stages of liver disease (P = 0.024).

CONCLUSION

This study highlights that the vast majority of Saudi patients with chronic hepatitis B have genotype D. No correlation could be observed between the different genotypes and epidemiological or clinical factors. The relationship between genotype D and HBeAg status in terms of disease severity needs to be further elucidated in larger longitudinal studies.

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

BACKGROUND/AIMS

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Hepatitis B virus reactivation in patients receiving chemotherapy for malignancies: role of precore stop-codon and basic core promoter mutations

Hepatitis B virus (HBV) strains carrying the precore stop-codon mutation (A1896) have been considered among the predisposing factors for reactivation during chemotherapy for malignancies. The role of the T1762/A1764 basic core promoter (BCP) mutations has not been fully evaluated. We aimed to record any changes in HBV serological markers after reactivation, detect the presence of A1896 and BCP mutations and evaluate the type of cytotoxic drugs involved. We retrospectively screened eight patients presenting with HBV reactivation following chemotherapy for malignancies. The chemotherapy regimens used included corticosteroids (CSs), fludarabine and cyclophosphamide/adriamycine. The INNO-LiPA HBV PreCore kit was used for the detection of the A1896 and BCP mutations. Six patients who were hepatitis B surface antigen (HBsAg)-(+)/hepatitis B e antigen (HBeAg)-(-) before chemotherapy, had disease reactivation following a mean of four cycles of chemotherapy. Four survived and two died of hepatic failure. At the time of reactivation, all six patients carried the A1896 and five of them the BCP mutations. The remaining two patients were HBsAg-(-)/anti-HBs-(+)/anti-hepatitis B core (HBc)-(+)/HBeAg-(-) before chemotherapy. One of them reverted to HBeAg-(+) status but remained HBsAg-(-), while the other became HBsAg-(+)/HBeAg-(+), following three and eight cycles of fludarabine treatment, respectively. The former carried the A1896 and the latter the wild-type virus. Both died from causes associated with their haematological disease. All but one of our patients with HBV reactivation during chemotherapy carried the precore stop-codon and BCP mutations. Whether this occurs more frequently in such patients than those carrying the wild-type virus needs further investigation. Fludarabine should be added to the list of drugs inducing HBV reactivation. HBV reactivation following fludarabine treatment occurred in HBsAg-(-) patients who had been anti-HBs-(+).

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.

Low HBV-DNA levels in end-stage renal disease patients with HBeAg-negative chronic hepatitis B

In end-stage renal disease patients treated by hemodialysis with HBeAg-negative chronic hepatitis B virus (HBV) infection, the evaluation of the presence of viral replication is essential in the assessment for renal transplantation. Data on HBV viral load, prevalence of precore mutations, as well as the influence of HCV coinfection on HBV-DNA levels in this group of patients is scarce. The aim of this study was to determine the HBV viral load in HBsAg-positive/HBeAg-negative hemodialysis patients; to compare HBV-DNA levels between isolated HBV infection carriers and HBV-HCV coinfected patients, and to evaluate the prevalence of precore mutations in these patients. Fifty hemodialysis patients with chronic HBeAg-negative HBV infection were studied. Viral load was determined by PCR (Amplicor HBV Monitor-Roche). The detection of precore mutations was made by sequencing. Of a total of 50 patients, 76% were male, with a mean age of 44 +/- 11 years. Anti-HCV was positive in 56% of patients. HBV-DNA was undetectable in 58% of patients; 24% had HBV-DNA <10,000 copies/ml, 12% between 10,000-100,000 copies/ml, and only 6% had HBV-DNA >100,000 copies/ml. There was no difference in the viral load of patients infected only by HBV and HBV-HCV co-infected patients (P = 0.96). Precore mutations were detected in only 8% of cases. In conclusion, hemodialysis patients with HBeAg-negative HBV infection had a low viral load. Precore mutations were infrequent and the presence of anti-HCV has not influenced the levels of HBV-DNA.

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

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

Complete genomic sequence and phylogenetic relatedness of hepatitis B virus isolates from Iran

Hepatitis B virus (HBV) is one of the main etiological agents of acute and chronic liver disease that is still a major public health problem in the world. Numerous HBV isolates have grouped into eight genotypes, A to H, based on the complete genome sequence. To date, no study has been carried out on the complete HBV genome sequence in Iran. The objective of this study was to investigate the complete genome sequence organization and phylogenetic analysis of the five HBV strains, which obtained from Iranian chronic infected patients. Results showed that Iranian strains were closely related to each other, with 97-100% nucleotide similarity. Phylogenetic analysis based on the complete genome sequences and the precore/core gene sequences revealed that all strains were of genotype D, sub-genotype D1 with bootstrap value 100 and 99%, respectively. The S gene encoded Arg122, Pro127, and Lys160 corresponding to subtype ayw2. Iranian HBV isolates had closely related with Turkish HBV strains. All strains had a nucleotide length of 3,182 base pair (bp) except IR-P4 strain, with a 3,185 bp in length and with a unique Phe89 insertion in the X gene. The intragenotypic divergence of the complete genome sequence of Iranian strains was 1.8% and the intergenotypic in genotype D was 3.8% and with the other genotypes was 7.9-15.4%. In conclusion, this study revealed that the HBV genotype D, sub-genotype D1, subtype ayw2 dominates in the Iranian infected patients. A single Phe89 insertion in the X gene of the one Iranian strain with an unforeseen length of 3185 bp was identified.

Validation and comparison of different PCR-based methods for detection of hepatitis B virus precore region mutants

Hepatitis virus variants detection is useful in clinical practice; however, methods that are used for their identification may influence the results significantly. Three PCR-based assays for quantitation of G1896A precore HBV mutants: two allele specific PCRs, single tube (single-AS-PCR) with enzymatic restriction or separate tubes (twin-AS-PCR) and one oligohybridization assay (OA) with three probes were developed and standardized. Wild type and mutant plasmids and 10 sera were used as reference. All methods had sensitivity limits of 10(4)copies/ml and their specificity encompassed 3 logs (10(4)-10(7)copies/ml) with dynamic ranges of logs for OA, twin-AS-PCR and single-AS-PCR, respectively. Single-AS-PCR and OA detected minor viral populations when their relative prevalence was at least 10% of the overall viral population whereas their detection by twin-AS-PCR ranged from 0.1 to 10% for samples with 10(7) and 10(5)copies/ml viral loads, respectively. Twin-AS-PCR was the most sensitive to detect the minor viral population, whereas single-AS-PCR and OA were more accurate to quantify the relative proportions of the two viral populations independently of the overall viral load. In conclusion, an accurate characterization of HBV precore heterogeneity should be warranted by a careful choice of the most appropriate assay according to the aim of the study.

The relationship between HBV-DNA levels and cirrhosis-related complications in Chinese with chronic hepatitis B

We studied the hepatitis B virus (HBV)-DNA levels below which the development of cirrhosis-related complications became unlikely in chronic hepatitis B (CHB). Seventy-nine Chinese CHB patients with cirrhosis-related complications and 158 age-, sex- and HBeAg status-matched patients without complications were enrolled. The precore and core promoter mutations were detected by the Line Probe assay (LiPA). HBVDNA levels were determined by Digene assay and Cobas Amplicor Monitor test. Patients with complications had higher HBVDNA levels than those without complications (P = 0.02). HBeAg-positive patients with complications had similar alanine transferase (ALT) and HBVDNA levels and frequency of precore mutations, but higher frequency of core promoter mutations (P = 0.003), compared with those without complications. Anti-HBe-positive patients with complications had higher ALT and HBVDNA levels (P < 0.01) but similar frequency of precore and core promoter mutations, compared with those without complications. Anti-HBe patients (24.5%) with complications had HBVDNA levels <10(4) copies/mL. The major factor for the development of cirrhotic complications was viral loads but cirrhotic complications continued to develop in patients with HBVDNA levels below 10(4) copies/mL.

A novel accurate amplification created restriction site method for determination of the wild type and the precore mutant hepatitis B virus variants

The most commonly occurring hepatitis B virus (HBV) mutation is the G to A mutation at nucleotide 1896 in the precore region. The aim of this study was to develop a novel accurate amplification created restriction site (ACRS) method for determination of the TGG wild type and the TAG precore mutant HBV variants. Two conserved and consensus specific and diagnostic primers introducing BstXI and XagI cleavage sites were designed in order to determine the G1896 wild type and the A1896 precore mutant HBV variants in all HBV genotypes. The results of the ACRS method were compared with sequencing data. With the ACRS method, three different patterns could be distinguished for the wild type, the precore mutant and mixed infection HBV variants. The results of the ACRS method on 30 HBV isolates revealed the TAG precore mutant in 50% (15/30), the TGG wild type variant in 30% (9/30) and the mixed infection in 20% (6/30). The sequencing data of these samples were in agreement with the ACRS results. The ACRS method is a rapid and cost-effective technique for detecting both the TGG wild type and the TAG HBV precore mutant variants. It can be carried out for follow-up of G1896A precore mutant variant in hepatitis B virus infected subjects at routine molecular diagnostic laboratories.

High frequency of the 1896 precore mutation in patients and blood donors with hepatitis B virus infection from the Indian subcontinent

AIM

Hepatitis B virus (HBV) e antigen (HBeAg)-negative variants are reported to harbor 1896 precore mutants, and predict a worse clinical outcome. The aim of this study was to estimate the incidence of a precore mutation (1896) in both patients with chronic hepatitis B (CH-B) infection and blood donors in a tertiary care hospital in south India.

METHODS

One hundred and twenty-two consecutive HBV DNA-positive CH-B patients (group I) and 102 HBsAg-positive 'healthy' blood donors (group II) were recruited. Samples found to be positive for HBV DNA were further studied. A nested PCR was used for the detection of HBV DNA. The 1896 precore mutation was detected using PCR-restriction fragment length polymorphism (RFLP). Nucleotide sequencing was performed on representative samples to confirm PCR-RFLP findings. The study population was stratified comprising: group IA: 17 HBeAg-positive CH-B patients; group IB: 105 HBeAg-negative CH-B patients; group IIA: 12 HBeAg-positive blood donors; and group IIB: 55 HBeAg-negative blood donors.

RESULTS

There was no significant difference in the HBeAg-positive status between groups I and II. Significantly higher levels of alanine transaminase (ALT) were seen in groups IA and IB than in groups IIA and IIB, respectively (p = 0.033; p = 0.004). A significantly higher proportion of CH-B patients (32.7%) were positive for anti-HBc IgM compared with the blood donor groups (10.4%; p = 0.0006). Among the HBeAg-negative subjects, 69% of the CH-B patients and 65% of the blood donors showed evidence of 1896 precore mutant. This infection included the 1896 mutant exclusively or mixed infection involving the 1896 mutant and 1896 wild-type.

DISCUSSION

The absence of detectable HBeAg in most of the viremic blood donors and patients emphasizes the need for HBV DNA testing irrespective of HBeAg status. Mixed infection was detected in a higher proportion (42.6%) of CH-B patients than in blood donors (26.8%; p = 0.031). Among those with mixed infection, a significant proportion (44.2%) of CH-B patients, had ALT levels greater than the upper limit of normal (ULN), as compared with the blood donor groups (16.6%; p = 0.036).

CONCLUSIONS

The majority of CH-B patients and blood donors were negative for HBeAg despite their positive HIV DNA status. About two-thirds of the HBsAg-positive blood donors were viremic. Mixed infection was detected more frequently in CH-B patients and appears to be associated with more pronounced liver damage, as indicated by increased ALT levels.

Clinical significance of hepatitis B virus genotypes, variants, and mutants

Emerging evidence suggests that hepatitis B virus (HBV) genotypes may influence the rate of spontaneous and interferon-induced hepatitis B e antigen (HBeAg) seroconversion as well as the natural history of liver disease. In contrast, the dinical significance of precore and core promoter variants associated with HBeAg negative liver disease is less certain in light of the many competing host and virologic factors noted in reported studies. HBV surface mutants are primarily associated with prior vaccine or hepatitis B immune globulin exposure and do not appear to have untoward virulence or association with occult HBV infection. Polymerase mutants with reduced drug sensitivity and phenotypic resistance are commonly detected in patients receiving prolonged antiviral therapy and have a variable impact on disease outcomes. The introduction of additional nucleoside/nucleotide analog agents will likely lead to the development of further unique polymerase mutants with varying pathogenicity and cross-resistance to existing drugs.

Adefovir dipivoxil for the treatment of hepatitis B e antigen-negative chronic hepatitis B

BACKGROUND

Adefovir dipivoxil, a nucleotide analogue, demonstrated clinically significant antiviral activity in patients with chronic hepatitis B in phase 1 and 2 clinical trials.

METHODS

We randomly assigned 185 patients with chronic hepatitis B who were negative for hepatitis B e antigen (HBeAg) to receive either 10 mg of adefovir dipivoxil or placebo once daily for 48 weeks in a 2:1 ratio and a double-blind manner. The primary end point was histologic improvement.

RESULTS

At week 48, 64 percent of patients who had base-line liver-biopsy specimens available in the adefovir dipivoxil group had improvement in histologic liver abnormalities (77 of 121), as compared with 33 percent of patients in the placebo group (19 of 57, P<0.001). Serum hepatitis B virus (HBV) DNA levels were reduced to fewer than 400 copies per milliliter in 51 percent of patients in the adefovir dipivoxil group (63 of 123) and in 0 percent of those in the placebo group (0 of 61, P<0.001). The median decrease in log-transformed HBV DNA levels was greater with adefovir dipivoxil treatment than with placebo (3.91 vs. 1.35 log copies per milliliter, P<0.001). Alanine aminotransferase levels had normalized at week 48 in 72 percent of patients receiving adefovir dipivoxil (84 of 116), as compared with 29 percent of those receiving placebo (17 of 59, P<0.001). No HBV polymerase mutations associated with resistance to adefovir were identified. The safety profile of adefovir dipivoxil was similar to that of placebo.

CONCLUSIONS

In patients with HBeAg-negative chronic hepatitis B, 48 weeks of adefovir dipivoxil treatment resulted in significant histologic, virologic, and biochemical improvement, with an adverse-event profile similar to that of placebo. There was no evidence of the emergence of adefovir-resistant HBV polymerase mutations.

Influence of hepatitis B virus genotype on the long-term outcome of chronic hepatitis B in western patients

BACKGROUND & AIMS

The aim of this study was to investigate if the variable outcome of chronic hepatitis B may be related to hepatitis B virus (HBV) genotype.

METHODS

The clinical and virologic events observed over prolonged follow-up in 258 Spanish patients with chronic hepatitis B infected with different genotypes of HBV were compared.

RESULTS

The prevalence of genotype A, D, and F was 52%, 35%, and 7%, respectively. Concomitant sustained biochemical remission and clearance of HBV DNA occurred at a higher rate in genotype A- than in genotype D- (log-rank, 14.2; P = 0.002) or genotype F-infected patients (log-rank, 4.2; P = 0.03). The rate of hepatitis B surface antigen (HBsAg) clearance was higher in genotype A than in genotype D hepatitis (log-rank, 4.6; P = 0.03). Sustained remission and clearance of HBsAg were associated with infection with genotype A by Cox regression analysis. Seroconversion to antibody to hepatitis B e antigen (anti-HBe) was unrelated to HBV genotype, but the rate of sustained remission after seroconversion was higher in genotype A than in genotype D hepatitis both in patients who seroconverted to anti-HBe during follow-up (log-rank, 4.5; P = 0.03) and in patients with positive anti-HBe at baseline (log-rank, 6.66; P = 0.009). Death related to liver disease was more frequent in genotype F than in genotype A (P = 0.02) or genotype D (P = 0.002) hepatitis.

CONCLUSIONS

The long-term outcome of chronic hepatitis B is different in patients infected with HBV genotype A, D, or F.

Histologic activity of childhood chronic hepatitis B related to viremia levels, genotypes, mutations, and epidemiologic factors

BACKGROUND

Despite high viral load, children with chronic hepatitis B virus (HBV) infection may lack significant biochemical signs of liver dysfunction. Failure to develop abnormal liver chemistriesis is probably due to immunologic hyporeactivity. Despite the absence of biochemical abnormalities in these patients, there is still a risk for long-term complications. The pathogenic importance of viral load and genetic variability is less well studied in children than in adults.

METHODS

We evaluated viremia levels, genotypes, and mutations related to histologic evidence of liver damage in 71 HBV carriers, aged 2 to 18 years, all of non-Swedish origin.

RESULTS

None of the of 22 children who were hepatitis B e antigen (HBeAg) negative had severe liver disease or had HBV DNA levels greater than 10 copies/mL (mean 10 ); 3 (14%) of them had increased alanine aminotransferase (ALT). The 49 HBeAg-positive children had a mean HBV DNA level of 10 copies/mL, and increased ALT was seen in 28 (55%). Core promoter mutations (at nt 1764) or precore mutations (at codon 1, 2, or 28) were rare; they were seen in four and one HBeAg-positive children, and in four and nine HBeAg-negative children, respectively, without association to liver damage. C-1858 was associated with more liver inflammation. Genotype did not significantly influence liver damage. Children with horizontal transmission had a faster rate of seroconversion and more inflammation of the liver.

CONCLUSIONS

Severe HBeAg-negative hepatitis with high HBV DNA levels and mutations in the core promoter or precore regions seems to be less common in children than in adults. C-1858 strains may be more pathogenic, but this requires further study. Epidemiologic factors influence the course of infection.

'Hbe minus' mutants of hepatitis B virus. Molecular characterization and its relation to viral genotypes

The precore-core and S genes of HBV were directly sequenced from serum samples of 42 patients with chronic hepatitis B (16 hepatitis Be antigen [HBeAg]+and 26 anti-HBe+). Viral genotype A was identified in 12 cases, genotype D in 11 and genotype F in 19 cases. Precore mutations, mainly M1 (G1896A, stop at codon 28) were similarly found among viral genotypes A and D: seven cases (58%) and six cases (55%), respectively. The selection of M1 mutants from genotype D resulted in a more stable encapsidation signal but was less stable for genotype A precore mutants. Oddly enough, the encapsidation signal of M1 precore mutants from genotype F sequences were evenly distributed among less stable (genotype A M1 mutants) and more stable encapsidation signal (genotype D M1 mutants). This study shows that the selection of precore mutants that preclude the HBeAg expression, including the M1 mutation, does not necessarily depend on the stabilization of the encapsidation signal or the viral genotype In addition, the particular behavior of genotype F genomes at precore region is described.

Efficacy of lamivudine in HBeAg-negative chronic hepatitis B

Hepatitis B e antigen (HBeAg)-negative chronic hepatitis B results from infection with hepatitis B virus mutants unable to produce HBeAg. It accounts for 7-30% of patients with chronic hepatitis B virus (HBV) worldwide, with the highest rates reported for Mediterranean Europe and Asia. Interferon (IFN) is currently the only approved therapy for these patients, but it has an unfavorable tolerance profile and limited efficacy. Studies show that responses to IFN are lower in HBeAg-negative than in HBeAg-positive patients; joint HBV DNA loss/ALT normalization is obtained in 38-59% of HBeAg-negative patients treated for 4-24 months with a high rate of virological relapse (54-87%), at 6-24 months posttreatment. Lamivudine is a nucleoside analogue with potent antiviral properties against HBV. Studies show that response rates in HBeAg-negative and HBeAg-positive patients are equivalent. After 12 months of treatment, 65-96% of HBeAg-negative patients have joint HBV DNA loss/ALT normalization, although 48-74% of patients relapse within 1 year posttreatment. 60% of patients have histological improvement after 12 months of treatment. Lamivudine is well tolerated with a safety profile equivalent to that of placebo. The incidence of YMDD variants increases with extended lamivudine treatment, present in up to 57-64% of patients after 2 years. Their clinical impact is unclear; some studies show breakthrough infection associated with their emergence, whereas other studies show maintained response to lamivudine. Lamivudine has benefits over IFN in its safety and efficacy profile in this patient group. Extended lamivudine treatment beyond 2 years is an option, but further investigation is required to define stopping criteria and the impact of YMDD variants.

Clinical and virological aspects of blood donors infected with hepatitis B virus genotypes B and C

Pathogenic and therapeutic differences among hepatitis B virus (HBV) genotypes have been documented. However, the association of virological characteristics with clinical differences among HBV genotypes remains unclear. We therefore studied the clinical and virological characteristics of Taiwanese volunteer blood donors infected with HBV genotypes B and C. HBV genotypes were determined in 300 candidate blood donors positive for HBV surface antigen (HBsAg), and sequences of the precore gene of the HBV genome were determined in 50 HBV e antigen (HBeAg)-positive and 50 HBeAg-negative blood donors. Of 300 HBsAg-positive blood donors, 10% had elevated serum aminotransferase levels and 27% were positive for HBeAg. HBV genotype distribution in 264 viremic carriers was as follows: B, 221 (83.7%); C, 39 (14.8%); F, 1 (0.4%); and mixed infection, 3 (1.1%). Blood donors with genotype C infection tended to have a higher frequency of HBeAg positivity and a higher serum HBV DNA level than those with genotype B infection. The frequency of precore stop codon mutation was significantly higher in HBeAg-negative blood donors than HBeAg-positive ones, irrespective of HBV genotypes. Meanwhile, only 5% of blood donors with genotype C infection had C-1858 strains. In conclusion, mixed infection of HBV genotypes indeed occurs, and genotype C has a higher serum HBV DNA level than genotype B. Precore stop codon mutation is common in HBeAg-negative HBV carriers, irrespective of HBV genotypes. In contrast, precore C-1858 strains are rarely identified in Taiwanese HBV genotype C.

Base-pair alterations in the epsilon-lower stem due to a novel double substitution in the precore gene of HBV-e negative variant were recovered by secondary mutations

The HBe negative phenotype, a natural precore mutant (G1896A/G1897A) of HBV with aborted HBeAg expression is known to cause chronic hepatitis. The destabilized C : G base-pairing in the lower stem of epsilon-hairpin due to G1896A substitution is reportedly compensated by a second C1858T mutation and suggested to play an important role in enhanced selection of the HBe negative variant. We undertook to investigate presence of such compensatory mutations at other positions by analyzing epsilon-sequences (nts. 1847-1907) as well as to look for their effect(s), if any, on the consensus sequence of the overlapping core-initiator of HBe negative HBV variants in CLD patients. Three of the 5 HBe negative patients had classical G1896A mutation having a second compensatory mutation at nt. 1858. One patient showed an additional G1897A substitution, presenting as a novel precore stop codon mutation (UGG-->UAA), followed by a compensatory mutation at position 1857. In the third patient, a G1899A substitution was seen which compensated the impaired U at position 1855. Other substitution and deletion mutations were also observed in the remaining epsilon-hairpin, which however, did not produce any compensatory mutation. Further, all the precore variants showed a conserved G at position 1904, important for the optimal context of their core-initiator which however, remained impaired with A (nt. 1850). Our results suggest that the nts. 1851-1859 and nts. 1895-1904 in the lower stem, and restoration of authentic base-pairings therein, maintain the structural integrity and stability of the epsilon-hairpin. This may have a role in the enhanced selection of the HBe negative variants and persistence of HBV infection in chronic liver disease patients.

Structural and functional heterogeneity of naturally occurring hepatitis B virus variants

Most organisms have developed sophisticated machineries to preserve their genomic integrity. On the contrary hepatitis B virus (HBV), like a lot of other viruses can undergo rapid and drastic sequence changes, especially if the virus has to cope with natural or therapy induced antiviral mechanisms in the host. Here, we try to summarize possible implications for the molecular pathogenesis of HBV based on the extensive research on the genetic variants of HBV.

Phylogenetic origin of hepatitis B virus strains with precore C-1858 variant

Mutations that prevent the expression of the hepatitis B e antigen frequently emerge in the immunoreactive phase of infection. The predominant mutation, the precore G-->A-1896 mutation, is restricted by the variability at position 1858 and is rare in strains with cytosine at nucleotide 1858. The C-1858 variant is characteristic of genotype A. It also occurs in genotypes C and F, but not in B, D, or E, explaining the geographical variation in the prevalence of precore mutants. C-1858 strains have been frequently observed in southeast Asia, but have not been phylogenetically characterized. By sequencing eight complete hepatitis B virus genomes, C-1858 variants of east Asian origin were found to constitute a phylogenetic entity within genotype C that probably diverged several hundred years ago. Further study of the distribution of this variant is warranted.

Low frequency of mutations in the core promoter and precore regions of hepatitis B virus in anti-HBe positive Brazilian carriers

BACKGROUND

Mutations in the core promoter and precore regions of the hepatitis B virus (HBV) genome, notably the double substitution (AGG to TGA) at nt positions 1762-1764 in the core promoter, and the precore stop codon mutation G to A at nt 1896, can often explain the anti-HBe phenotype in chronic carriers. However, the A1896 mutation is restricted to HBV isolates that have T at nt 1858. The double substitution at positions 1762-1764 has been described to occur preferentially in patients infected with strains showing C instead of T at nt 1858.

RESULTS

HBV DNAs from 29 anti-HBe Brazilian samples were characterized by nucleotide sequencing of PCR products from precore region. Among them, 18 isolates presented C at nt 1858 (mostly genotype A strains). The 11 remaining isolates (genotypes D and F) had T1858. The stop codon mutation at nt 1896 was found in seven isolates (24% of the total and 63% of the isolates that had T1858). The frequency of the double substitution at positions 1762-1764 was surprisingly low (20%) among C1858 isolates. An association between A1896 and TGA 1762-1764 mutations was observed among genotype D isolates: these showed either none of the two mutations or both. Furthermore, strains mutated at positions 1896 and/or 1762-1764 also presented an elevated number of other, less common substitutions in the core promoter and precore regions.

CONCLUSIONS

The data reported here are not in accordance with some reports from other parts of the world. In half of the isolates, none of the mutations previously described could explain the anti-HBe phenotype.

Rapid detection of genotypes and mutations in the pre-core promoter and the pre-core region of hepatitis B virus genome: correlation with viral persistence and disease severity

BACKGROUND/AIMS

We aimed to clarify the clinical relevance of hepatitis B virus pre-core mutant detection in patients with chronic hepatitis B using a newly developed assay.

METHODS

Viral genotypes and pre-core mutations were studied in relation to viral persistence and liver disease severity using INNO-LiPA methodology. The study group included 151 patients with chronic hepatitis B, 85 positive for HBeAg (group I) and 66 positive for anti-HBe (group II).

RESULTS

The prevalence of viral genotypes in group I was: 64% A, 1% B, 15% C, 19% D, 0% E, 0% F and in group II: 39% A, 0% B, 2% C, 56% D, 2% E, 2% F (p<0.001). The prevalence of mutations at pre-core codon 28 (M2) was lower in group I (5%) than in group II (64%) (p<0.001). The prevalence of pre-core promoter mutations was also lower in group I (21%) than in group II (61%) (p<0.001). M2 mutations were more frequently detected in genotype D than in genotype A (p<0.001), while the other mutations were not influenced by viral genotype. Serum HBV DNA levels were significantly lower in group II versus group I (p<0.001), and in patients with any of the pre-core mutations versus wild-type sequence (p<0.01). Although cirrhosis was more frequent in group II (37%) versus group I (22%) and in patients with either one of the pre-core mutation (31%) versus wild-type sequence (25%), there was no statistical difference in liver severity assessed by ALT levels and Knodell score.

CONCLUSION

Pre-core mutants, whose molecular pattern is strongly dependent on viral genotypes, are associated with viral persistence in anti-HBe positive patients with ongoing chronic hepatitis B. The availability of this rapid assay should allow a precise monitoring of viral pre-core mutants during the course of chronic hepatitis B.

Mutations of the core promoter and response to interferon treatment in chronic replicative hepatitis B

In chronic replicative hepatitis B the significance of mutations in the basic core promoter (BCP), core upstream regulatory sequences (CURS) and negative regulatory element (NRE) for response to interferon (IFN) is unknown. A sequence analysis of the NRE, CURS, BCP, and precore region was performed from sera of 96 patients with chronic replicative hepatitis B (64 hepatitis B e antigen [HBeAg]-positive patients and 32 HBeAg-negative patients) treated with alfa-IFN (IFN-alpha). The overall sustained response (SR) rate to IFN was 30% with no significant difference between HBeAg-positive and HBeAg-negative patients. IFN responsiveness correlated to hepatitis B virus (HBV)-DNA levels, hepatitis B surface antigen (HBsAg) levels, the number of mutations in the complete BCP, especially nucleotide (nt) region 1753 to 1766 and mutations at nt 1762 and 1764. In HBeAg-positive hepatitis, SR to IFN was associated with a high number of mutations in the BCP (P <.04) and nucleotide region 1753 to 1766 (P <.015) as well as mutations at nucleotide 1764 (P <.007). In HBeAg-negative hepatitis, SR to IFN correlated with a low number of mutations in the BCP (P <.04) and nucleotide region 1753 to 1766 (P <.02) and a wild-type sequence at nt 1764 (P <.003). Prediction of IFN response was possible on the basis of nt 1764 in 77% of HBeAg-positive patients and 78% of HBeAg-negative patients. IFN response did not correlate with the occurrence of the 1896 mutation, mutations in the CURS or NRE, disease duration, ethnic origin of the patient, alanine transaminase (ALT) levels and HBV genotype. Our data suggest that HBV genome mutations located within the BCP are determinants of a response to IFN therapy.

A new genotype of hepatitis B virus: complete genome and phylogenetic relatedness

The hepatitis B virus (HBV) genotype was determined in a total of 121 plasma samples collected in France and the US from patients chronically infected with HBV. HBV genotype A was predominant in this collection, appearing in 66 samples (54%), while genotypes B, C, D, E and F occurred in 4 (3%), 14 (12%), 23 (19%), 1 (1%) and 0 (0%) of samples, respectively. However, the genotype of a total of 13 (11%) samples (2 from France, 11 from the US) could not be determined with the methodology used. Sequence analysis, and subsequent phylogenetic analysis of the complete genome and the individual open reading frames, showed that the virus isolate from these samples was 3248 bp long and, phylogenetically, did not cluster with any of the known genotypes. This strain was provisionally called HBV genotype G. Virus isolates that were obtained from geographically separated regions like France and the US were closely related to each other. All virus strains analysed contained some characteristic differences when compared to genotype A: a translational stop codon at aa 2 and 28 of the preCore region; a 36 nt (12 aa) insert in the amino-terminal part of the Core antigen (HBcAg); a 2 aa deletion in the carboxy-terminal part of HBcAg; and a 1 aa deletion in the preS1 open reading frame. The deduced amino acid sequence of HBsAg suggests that this newly discovered genotype G strain belongs to serological group adw2.

Long-term mutation rates in the hepatitis B virus genome

Mutations in the hepatitis B virus (HBV) genome have so far been investigated in cross-sectional or short-term longitudinal studies. Information about long-term changes is lacking due to the difficulty of sampling over long observation periods. In this study, a retrospective approach was used that allowed the analysis of changes in the viral genome from transmission to late stages of infection without the requirement for sampling early during this period. The entire viral genome was sequenced from serum samples of three mothers and their 10 adult children, who presumably had been infected vertically. The emergence of mutations between birth and sampling (mean 26.5 years) was assessed by comparing the individual sequences with the sequence of the strain assumed to have been transmitted. The mean differences from this sequence were 0.02 and 0. 28% in seven asymptomatic and one symptomatic hepatitis B e antigen (HBeAg)-positive carriers, respectively, and 0.62 % in five HBeAg-negative carriers. Mutations occurred throughout the genome and 88% of the mutations caused amino acid substitutions spread over all genes. In HBeAg-negative carriers, the number of nucleotide and amino acid changes was independent of the severity of liver disease and, except the (1762)AGG(1764)-->TGA changes, no specific mutation was associated with liver disease. In conclusion, by using a novel method it was found that the entire HBV genome is extremely stable over long periods of time during the HBeAg-positive phase if the immune response (inflammation) is weak, whereas an average of 20 mutations emerged after development of hepatitis and/or loss of HBeAg without association with clinical outcome.

Does hepatitis B virus (HBV) genotype influence the clinical outcome of HBV infection?

Between 5 and 10% of adults infected with the hepatitis B virus (HBV) develop a chronic infection lasting longer than 6 months, which may lead to advanced liver disease. HBV can be classified into six genotypic families: A, B, C, D, E and F, but only genotypes A and D are significantly represented in western Europe, where they account for some 90% of cases of infection with HBV. In the present study, we investigated a possible association between HBV genotype A or D and clinical outcome of the infection. We compared the prevalence of these genotypes in a group of patients with chronic active hepatitis to that of a group with acute resolving hepatitis. In patients with chronic active hepatitis, genotype A was found in 28 of 35 patients and genotype D in only four. The remaining three patients were infected with genotype non-A, non-D. In contrast, genotype D was found in 24 of 30 patients with acute hepatitis, whilst genotype A was found in only three patients of this group. Three were infected with genotype non-A, non-D. Our results show a clear association between genotype A and chronic outcome (Ficher's exact test: two-sided P-value, P < 0.0001). They suggest that HBV genotypes may play a role in the virus-host relationship. Possible mechanisms for such a role are discussed.