Prevalence of HBV precore/core promoter variants in the United States

Comparison of complete sequences of hepatitis B virus genotype C between inactive carriers and hepatocellular carcinoma patients before and after seroconversion

BACKGROUND

Most patients who acquire chronic hepatitis B virus (HBV) infection by perinatal transmission become inactive carriers (IC) after hepatitis B e (HBe) antigen seroconversion, whereas some patients have persistent abnormal serum transaminase levels and develop hepatocellular carcinoma (HCC) in the anti-HBe-positive phase. The aim of this study was to investigate the HCC-related mutations of HBV.

METHODS

Complete sequences of HBV were examined among eight IC and eight HCC patients infected with HBV genotype C before and after seroconversion.

RESULTS

The frequency of the T1653 mutation tended to be higher among HCC patients after seroconversion (16.7% vs. 62.5%; P = 0.086). The prevalence of a basal core promoter double mutation (T1762/A1764) was high among both IC and HCC patients after seroconversion (83.3% vs. 87.5%; P = 0.825). Among the HCC patients, a pre-S deletion mutant was detected in 62.5% patients before seroconversion, and in 37.5% patients after seroconversion. The core deletion mutant was also detected in 50% of HCC patients only before seroconversion. Deletion mutants of the pre-S or core region before seroconversion were significantly associated with HCC patients (0% vs. 62.5%; P = 0.007, 0% vs. 50%; P = 0.021, respectively).

CONCLUSIONS

Our data showed a significant association of pre-S and core deletion mutants before seroconversion with HCC development. The T1653 mutation after seroconversion was frequently found in HCC patients infected with HBV genotype C. These results suggest that mutations may be predictive factor for development of HCC.

Lamivudine/pegylated interferon alfa-2b sequential combination therapy compared with lamivudine monotherapy in HBeAg-negative chronic hepatitis B

BACKGROUND AND AIM

Monotherapy has been proven insufficient in achieving sustained control of chronic hepatitis B. We aimed to assess the efficacy of combined sequential administration of lamivudine and pegylated interferon alfa-2b in patients with hepatitis Be antigen (HBeAg)-negative chronic hepatitis B.

METHODS

Eighteen patients were given sequential combination treatment starting with 3 months of lamivudine monotherapy followed by 9 months of pegylated interferon alfa-2b (after a 3-month period of concomitant administration of the two drugs) and 24 patients received lamivudine monotherapy.

RESULTS

At the end of treatment, 88.9% of the patients who received sequential combination treatment and 70.8% of those who received lamivudine monotherapy had hepatitis B virus (HBV) DNA levels below 400 copies/mL (P = not significant). At the end of treatment, 72.2% of the patients who received sequential combination treatment and 70.8% of those who received lamivudine monotherapy achieved alanine aminotransferase normalization (P = not significant). After 12 months of follow up, 33.3% of the patients who received sequential combination treatment and 16.7% of those who received lamivudine monotherapy had HBV-DNA levels below 400 copies/mL (P = 0.4). After 12 months of follow up, 72.2% of the patients who received sequential combination treatment and 25.0% of those who received lamivudine monotherapy had normal alanine aminotransferase levels (P < 0.01). Twenty-five percent of the patients in the lamivudine monotherapy group had virological breakthrough compared to none in the sequential combination treatment group (P = 0.06).

CONCLUSIONS

Sequential combination treatment is able to improve sustained biochemical response rates and prevent the emergence of lamivudine-resistant mutants in patients with HBeAg-negative chronic hepatitis B.

Impaired intrahepatic hepatitis B virus productivity contributes to low viremia in most HBeAg-negative patients

BACKGROUND & AIMS

Knowledge of factors regulating transcriptional activity of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) may help in understanding mechanisms of viral decay and how these processes are thwarted in chronically HBV-infected patients.

METHODS

Liver biopsies from 119 treatment-naive chronically infected patients (42 HBeAg-positive and 77 HBeAg-negative) were determined for HBV transcriptional and replicative activity.

RESULTS

Significantly lower median serum HBV DNA (-4 log), intrahepatic HBV DNA (-2 log), and cccDNA (-1 log) amounts were measured in HBeAg-negative versus HBeAg-positive patients. Despite a good correlation found between intrahepatic amounts of progeny virions and serum HBV DNA in all patients, cccDNA levels did not correlate with serum titers in HBeAg-negative individuals. Analysis of HBV RNA transcripts showed that impaired virion productivity in HBeAg-negative individuals was due to lower steady-state levels of pregenomic RNA produced per cccDNA. Interestingly, preS/S RNA levels and serum HBsAg concentrations did not differ between HBeAg-positive and HBeAg-negative patients when normalized for cccDNA contents, showing that subviral particle production was not impaired in HBeAg-negative patients and correlated with cccDNA levels. Although the majority of HBeAg-negative individuals harbored cccDNA with common precore and/or basal core promoter mutations, occurrence of these variants was not responsible for reduced viral replication. Instead, replacement of wild-type cccDNA with core promoter mutants reestablished high virion productivity.

CONCLUSIONS

Lower viremia in HBeAg-negative individuals is not only due to lower cccDNA content but also to impaired virion productivity, which can arise without emergence of HBeAg variants and without affecting HBsAg production.

Epidemiology of chronic hepatitis B infection in France: risk factors for significant fibrosis--results of a nationwide survey

BACKGROUND

Epidemiological data concerning hepatitis B are scarce in France.

AIM

To describe epidemiological, clinical, virological and histological features of HBsAg-positive patients followed at non-academic hospitals in France.

METHODS

Clinical, biological, virological and histological data of all HBsAg-positive consecutive patients observed from April 1, 2001 to May 31, 2002 in participating centres were recorded prospectively. Multivariate analyses of factors associated with significant fibrosis and cirrhosis were performed.

RESULTS

Nearly 1166 HBsAg-positive patients were seen in the 58 centres: 671 males and 495 females from metropolitan France (32%) and from outside metropolitan France (68%); mean age 41 +/- 15 years. Twenty-nine percent of patients were probable HBsAg inactive carriers, while 50% had chronic hepatitis; 43% of these were HBeAg-positive and 57% HBeAg-negative. Liver biopsy had been performed in 558 (51%) patients; 205 (17.6%) patients had cirrhosis. By multivariate analysis, factors associated with significant fibrosis were: age >40 years (P < 0.05), HBeAg-negative status (P < 0.02) and histological activity (P < 0.0001). Factors associated with cirrhosis: age (P < 0.0001), platelet count <150 000/mm(3) (P < 0.0001) and viral co-infection (P < 0.03).

CONCLUSION

HBV infection represents a significant workload for hepatogastroenterologists at non-academic hospitals in France.

Natural history of hepatitis B virus infection: an update for clinicians

Hepatitis B virus (HBV) is a common viral pathogen that causes a substantial health burden worldwide. Significant progress has been made in the past few decades in understanding the natural history of HBV infection. A dynamic balance between viral replication and host immune response is pivotal to the pathogenesis of liver disease. In immunocompetent adults, most HBV infections spontaneously resolve, whereas in most neonates and infants they become chronic. Those with chronic HBV may present in 1 of 4 phases of infection: (1) in a state of immune tolerance, (2) with hepatitis B e antigen (HBeAg)positive chronic hepatitis, (3) as an inactive hepatitis B surface antigen carrier, or (4) with HBeAg-negative chronic hepatitis. Of these, HBeAg-positive and HBeAg-negative chronic hepatitis may progress to cirrhosis and its long-term sequelae including hepatic decompensation and hepatocellular carcinoma. Several prognostic factors, such as serum HBV DNA concentrations, HBeAg status, serum aminotransferases, and certain HBV genotypes, have been identified to predict long-term outcome. These data emphasize the importance of monitoring all patients with chronic HBV infection to identify candidates for and select optimal timing of antiviral treatment, to recognize those at risk of complications, and to implement surveillance for early detection of hepatocellular carcinoma.

Hepatitis B Virus Genotypes and Lamivudine Resistance Mutations in HIV/Hepatitis B Virus-Coinfected Patients

BACKGROUND

Differences in subtypes, hepatitis B early antigen (HBeAg)-negative variants, and drug resistance mutations all seem to influence the clinical and therapeutic outcome in patients with chronic hepatitis B virus (HBV) infection. Information available on the prevalence and distribution of distinct HBV variants in HIV-positive patients is scarce.

METHODS

All HIV-infected patients with persistent serum hepatitis B surface antigen and detectable HBV viremia were identified in a reference HIV clinic located in Madrid, Spain. HBV load, subtypes, precore (PC) and basal core promoter (BCP) variants, and lamivudine (LAM) resistance mutations were analyzed.

RESULTS

A total of 81 HBV/HIV-coinfected patients (4.1%) were identified in a population of 1968 HIV-positive patients. Plasma specimens with detectable HBV viremia could be obtained from 62 subjects, and this was the study population that underwent further virologic characterization. HBV genotype distribution was as follows: A (n = 27), D (n = 27), E (n = 1), F (n = 2), and G (n = 3). Two patients had mixed HBV genotypes (A/E and A/F). HBV subtype A was predominant (74%) among patients infected through sexual contact, whereas HBV-D was most frequent (74%) among intravenous drug users (P < 0.001). PC/BCP mutants were more frequent in patients with HBV-D than in those with HBV-A (63% vs. 18%; P < 0.01). Median time on LAM was 40 months; patients with HBV-A tended to show LAM resistance mutations more often (53% vs. 44%) and to develop them earlier (35 vs. 45 months) than patients with HBV-D. The dual L180M + M204V/I mutant was the predominant resistance pattern, although a triple rt173V + 180M + 204V, which acts as a vaccine escape mutant, was found in 1 individual. In the multivariate analysis, patients with LAM resistance mutations were significantly more frequently HBeAg-positive and older than individuals with wild-type HBV. Hepatitis-delta was recognized in 13 (21%) of these 62 HBV viremic patients, with no association with specific HBV variants.

CONCLUSION

Risk transmission group, age, and positive serum HBeAg are the main determinants of distinct HBV virologic variants, including HBV genotypes and LAM-resistant mutants, in HBV/HIV-coinfected patients.

Comparison of hepatitis B virus subgenotypes in patients with acute and chronic hepatitis B and absence of lamivudine-resistant strains in acute hepatitis B in Japan

Hepatitis B virus (HBV) has been classified into eight genotypes and can be further divided into several subgenotypes that have different geographic distributions. Because of increased human migration, the prevalence of rare subgenotypes is increasing in Japanese patients with acute hepatitis B. Lamivudine-resistant strains of HBV have begun to emerge in association with chronic hepatitis B. The aim of this study was to investigate the distribution of HBV subgenotypes and lamivudine-resistant strains in patients in Japan with acute hepatitis B. One hundred twenty-three patients with acute hepatitis B and 123 with chronic hepatitis B were studied. HBV subgenotypes and lamivudine-resistance mutations were determined by direct sequencing of the preS and polymerase region, respectively. HBV subgenotypes Aa (n=3), Ae (n=23), Ba (n=7), Bj (n=3), Cs (n=7), Ce (n=76), D (n=2), and H (n=2) were detected in patients with acute hepatitis. In patients with chronic hepatitis, HBV subgenotypes Ae (n=4), Ba (n=1), Bj (n=18), and Ce (n=100) were found. Non-common Japanese subgenotypes, that is, non-Bj and non-Ce, were detected more frequently in patients with acute hepatitis (35.8%) than in patients with chronic hepatitis (4.1%) (Odds ratio, 0.076; 95%CI, 0.029-0.200; P<0.0001). Lamivudine-resistance mutations were detected in chronic hepatitis patients with breakthrough hepatitis but not in other patients. In conclusion, the prevalence of uncommon Japanese HBV subgenotypes is expected to increase, although lamivudine-resistant strains have not yet been found in patients with acute hepatitis B.

Treatment of hepatitis B with lamivudine and tenofovir in HIV/HBV-coinfected patients: factors associated with response

As therapy for human immunodeficiency virus (HIV) infection evolves, optimizing hepatitis B virus (HBV) treatment and identifying factors that impact its response in the HIV/HBV-coinfected population is critical. We identified retrospectively 45 HBV/HIV-coinfected patients with detectable HBV DNA by the Bayer VERSANT HBV 3.0 bDNA assay (limit of quantification 2000 copies/mL) at baseline and/or year 1 of therapy. Patients were divided into three groups based on the active HBV agent in their antiretroviral regimen: group 1 (n = 15) received lamivudine; group 2 (n = 10), lamivudine plus tenofovir and group 3 (n = 20), lamivudine followed by lamivudine plus tenofovir. HBV genotypes and resistance profiles were determined by the Bayer Trugene HBV 1.0 assay. More patients in group 2 achieved HBV DNA suppression below 2000 copies/mL (80%), loss of HBe antigen (HBeAg) (40%) and loss of HBeAg and gain of anti-HBe (20%) than did patients in group 1 or 3. More patients with HBV genotype A, achieved HBV DNA suppression <2000 copies/mL than did patients with non-A genotypes [74% (26/35) vs 20% (2/10)], respectively (P = 0.003). Risk for virological nonresponse was significant in those with non-A genotypes [odds ratio (OR) 11.1; 95% CI: 2.0-50], previous HIV therapy (OR 6.5; 95% CI: 1.2-35) and <90% compliance (OR 3.7; 95% CI: 0.99-14.3). Simultaneous therapy with lamivudine/tenofovir suppresses HBV DNA more effectively than lamivudine or tenofovir added to lamivudine. More patients infected with HBV genotype A responded than the non-A patients, regardless of therapeutic regimen, compliance or prior HIV therapy.

Correlation of hepatitis B virus (HBV) genotypes and mutations in basal core promoter/precore with clinical features of chronic HBV infection

BACKGROUND/AIMS

To investigate the correlation of hepatitis B virus (HBV) genotypes and basal core promoter (BCP) and precore (PC) mutations in patients with chronic hepatitis B.

METHODS

HBV genotyping, nucleotide mutation, serum HBV DNA level and serological markers were analyzed in 121 patients with chronic HBV infection using INNO-LiPA HBV genotyping, polymerase chain reaction (PCR) product-based sequencing, fluorescence quantitative PCR and enzyme-linked immunosorbent assays respectively.

RESULTS

Forty (33.0%), 77 (63.6%), two (1.7%) and two (1.7%) patients had genotypes B, C, B/C and D infections respectively. Significant differences were found in serum HBV DNA levels (log10 copies/ml: 6.18 vs. 5.61, P=0.042) and mutations at nucleotide (nt) 1762/1764 (71.4% vs. 42.5%, P=0.002) between genotypes C- and B-infected patients. There were significant differences in the mean age, serum biochemical parameter levels and mutation rates in BCP/PC among hepatitis e antigen (HBeAg)-positive and -negative chronic hepatitis B (CHB) and liver cirrhosis (LC) groups.

CONCLUSION

Genotypes C and B are predominant in China, and the frequent nt 1762/1764 mutation, which occurs commonly in HBeAg-negative CHB, especially in genotype C patients, may be associated with the progress of chronic HBV infection.

Cost effectiveness of entecavir versus lamivudine with adefovir salvage in HBeAg-positive chronic hepatitis B

OBJECTIVE

To evaluate the cost effectiveness of treatment of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) with entecavir compared with lamivudine with adefovir salvage, based primarily on the results of a recent 2-year, randomised, multicentre, clinical trial (n = 709). Previous economic analyses have been limited by the lack of comparative clinical data for entecavir and lamivudine beyond 1-year duration and for salvage therapy.

METHODS

We conducted a cost-utility analysis using a Markov model from a US-payer perspective over a lifetime time horizon. The hypothetical cohort was 35-year-old patients with HBeAg-positive CHB. We evaluated 2 years of treatment with entecavir 0.5mg/day versus lamivudine 100mg/day, plus addition of adefovir 10mg/day for patients who developed virologic breakthrough due to resistance to either drug. In a scenario analysis, we considered adefovir plus lamivudine combination therapy for treatment-naive patients. Clinical and economic inputs ($US, year 2006 values) were derived from publicly available data, and probabilistic sensitivity analyses were conducted to evaluate uncertainty in the results.

RESULTS

The estimated 10-year cumulative incidence of cirrhosis for patients initiated on entecavir was 2.3% lower than for those on lamivudine (20.5% vs 22.8%). The discounted incremental cost per QALY gained was $US7600 in the base-case analysis, and the 95% central range from probabilistic sensitivity analysis was $US2500-$US19 100. Combination therapy for treatment-naive patients led to an increase in costs without improvement in patient outcomes compared with entecavir monotherapy.

CONCLUSIONS

Our analysis suggests entecavir improves health outcomes in a cost-effective manner compared with lamivudine with adefovir salvage or combination therapy, and highlights the importance of using evidence-based effectiveness estimates in economic studies of CHB therapies.

Chronic hepatitis B: current epidemiology in the Americas and implications for management

Hepatitis B virus (HBV) remains a serious health threat in many parts of the world. Although its prevalence is lower in the Americas than in Asia, Africa and the Middle East, it is responsible for significant morbidity and mortality in North, Central and South America. There is a nonuniform pattern of distribution throughout this region, with HBV prevalence related to geographical, social and cultural factors that predispose certain individuals to infection. This report details the incidence, modes of viral transmission of hepatitis B in the Americas and clinical course of disease in different regions of the Americas. Additionally, the implications for management focusing on issues predominant in high-risk populations are presented.

Precore/basal core promoter mutants and hepatitis B viral DNA levels as predictors for liver deaths and hepatocellular carcinoma

AIM: To conduct a retrospective study in 400 chronic hepatitis B patients in order to identify hepatitis B viral factors associated with complications of liver disease or development of hepatocellular carcinoma.

METHODS: The mean follow-up time was 83.6 ± 39.6 mo. Alpha-fetoprotein test and abdominal ultrasound were used for cancer surveillance. Hepatitis B basal core promoter mutants, precore mutants, genotypes, hepatitis B viral DNA (HBV DNA) level and hepatitis B e antigen (HBeAg) were measured. Univariate analysis and logistic regression were used to assess odds ratios for viral factors related to liver deaths and hepatocellular carcinoma development.

RESULTS: During follow-up, 38 patients had liver deaths not related to hepatocellular carcinoma. On multivariate analysis, older age [odds ratio: 95.74 (12.13-891.31); P < 0.0001], male sex [odds ratio: 7.61 (2.20-47.95); P = 0.006], and higher log₁₀ HBV DNA [odds ratio: 4.69 (1.16-20.43); P < 0.0001] were independently predictive for these liver related deaths. Also, 31 patients developed hepatocellular carcinoma. Multivariate analysis showed that older age [odds ratio: 26.51 (2.36-381.47); P = 0.007], presence of precore mutants [odds ratio: 4.23 (1.53-19.58); P = 0.02] and presence of basal core promoter mutants [odds ratio: 2.93 (1.24-7.57); P = 0.02] were independent predictors for progression to hepatocellular carcinoma.

CONCLUSION: Our results show that high levels of baseline serum HBV DNA are associated with non-hepatocellular carcinoma-related deaths of liver failure, while genetic mutations in the basal core promoter and precore regions are predictive for development of hepatocellular carcinoma.

Molecular analysis of hepatitis B virus isolates in Mexico: Predominant circulation of hepatitis B virus genotype H

AIM: To determine the genotypes in Mexican hepatitis B virus (HBV) isolates and characterize their precore and core promoter mutations.

METHODS: Forty-nine HBV isolates of Mexico obtained from sera of 15 hepatitis patients, 6 hemodialysis patients, 20 men seeking HIV testing, and 8 AIDS patients were analyzed. HBV isolates were amplified by PCR, and genotyped by line probe assay (INNO-LiPA HBV Genotyping; INNOGENETICS N V, Ghent, Belgium). HBV genotype confirmation was performed by DNA sequencing part of the sAg region. Precore and core promoter mutation characterization was performed by line probe assay (INNO-LiPA HBV PreCore; INNOGENETICS N V, Ghent, Belgium).

RESULTS: Overall, HBV genotype H was found in 37 (75.5%) out of the 49 isolates studied. HBV genotypes G, A, and D were found in 5 (10.2%), 4 (8.2%), and 3 (6.1%) isolates, respectively. HBV genotype H was predominant in isolates from hemodialysis patients (100%), hepatitis patients (80%), and men seeking HIV testing (75%), and accounted for half of infections in AIDS patients (50%). Six (12.2%) out of the 49 HBV isolates showed both wild type and mutant populations at precore codon 28. These mixed wild type and precore mutant populations were observed in one HBV genotype A isolate and in all HBV genotype G isolates. A dual variant core promoter mutation was observed in 1 (2%) of the isolates, which was genotype H.

CONCLUSION: HBV genotype H is highly predominant in HBV isolates of Mexico followed by genotypes G, A and D. A low frequency of precore and core promoter mutations is observed in HBV Mexican isolates.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Characteristics of patients with chronic hepatitis B in France: predominant frequency of HBe antigen negative cases

BACKGROUND/AIMS

An increasing prevalence of HBe antigen (HBeAg) negative chronic hepatitis B has been recently reported in many countries. The aim of this study was to analyze the frequency and the characteristics of HBeAg-negative as compared with HBeAg-positive chronic hepatitis B in France.

METHODS

Eight hundred and sixty-five patients with histologically proven chronic hepatitis B seen in 26 University centers were included. The proportion with HBeAg-negative chronic hepatitis B was 72% and higher in patients born in Africa, Middle East, Eastern, and Southern Europe than in those of French or Asian origin. HBeAg-negative patients were significantly older (p<0.001) and had lower ALT levels and HBV DNA serum levels (p<0.01) than HBeAg-positive patients. An unknown source of infection was more prevalent in HBeAg-negative patients (p<0.05). Fibrosis score (p<0.05) and proportion of cirrhosis (p<0.01) were significantly higher in HBeAg-negative patients. Age older than 50 years, male gender and viral load lower than 5 logs10 copies/mL were independently associated with cirrhosis.

RESULTS

HBeAg-negative chronic hepatitis B is predominant in France. This observation is important for an optimized clinical management and future therapeutic trials in chronic hepatitis B.

Hepatitis B virus genotypes, precore and core promoter variants among predominantly Asian patients with chronic HBV infection in a Canadian center

BACKGROUND AND AIMS

The epidemiology of hepatitis B virus (HBV) infection in North America may be changing as a result of immigration from endemic countries. The purpose of this study was to determine the prevalence of HBV genotypes, precore (PC) and core promoter (CP) variants, and the proportion of patients meeting treatment criteria for HBV.

METHODS

A cross-sectional study of consecutive HBV patients attending a Canadian tertiary liver center was conducted. HBV DNA was quantified by polymerase chain reaction assay. HBV genotypes and variants were determined using a line probe assay.

RESULTS

Two hundred and seventy-two patients were enrolled; 200 were not receiving treatment at enrollment, of whom 116 were men and 84 women with a mean age 42+/-14 years. Among this group, 177 (88%) patients were Asian and 19 (10%) were Caucasian and 69 (35%) patients were hepatitis B e antigen (HBeAg) positive. Genotypes B and C were found in 42% and 50% untreated patients, respectively; while CP and PC were detected in 52% and 43% patients, respectively. Approximately 20% patients not receiving treatment (29% HBeAg positive, 14% HBeAg negative) met AASLD guidelines for antiviral therapy. If lower cutoff values for alanine aminotransferase and HBV DNA levels were used, 49% patients would qualify for treatment.

CONCLUSIONS

The vast majority of patients at a Canadian tertiary referral center were Asian. Virological and clinical characteristics of these patients reflect their country of origin. Our findings highlight the need to monitor the changing patterns of HBV infection in countries with large immigrant populations.

Hepatitis B: the pathway to recovery through treatment

Hepatitis B is a major public health problem in the world today. Since 1985, the number of reported cases has declined as a direct result of universal immunization of neonates, vaccination of at-risk populations, lifestyle or behavioral changes in high-risk groups, refinements in the screening of blood donors, and the use of virally inactivated or genetically engineered products in patients with bleeding disorders. New and potent antiviral agents being developed and evaluated provide hope and optimism for those who are chronically infected with hepatitis B virus. Prevention remains the most effective strategy in the global management of hepatitis B virus. Universal immunization programs prevent hepatitis B virus transmission and circumvent acute and chronic infection.

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.

Prevalence of hepatitis B virus precore stop codon mutations in chronically infected children

AIM: To find out whether there is a significant difference in the prevalence of the precore stop codon mutation between HBeAg positive and anti-HBe positive children.

METHODS: We investigated a large pediatric population of 155 European children (mean age 10.9 years) with chronic hepatitis B by PCR and direct sequencing. Ninety were HBeAg positive and 65 had seroconversion to anti-HBe. Additionally genotyping was performed.

RESULTS: Seventy-four (48%) of the sequenced HBV strains were attributed to genotype D and 81 (52%) to genotype A. In the group of 90 HBeAg positive patients, 2 (2.2%) 1896-G-to-A transitions leading to precore stop codon mutation were found, and in the group of 65 anti-HBe positive children, 5 (7.7%) were identified harbouring HBeAg-minus mutants. The difference was not statistically significant (P= 0 .13).

CONCLUSIONS: HBeAg minus variants as predominant viral HB strains play a minor role in the course of chronic hepatitis B in European children.

A prospective study of the evolution of lamivudine resistance mutations in patients with chronic hepatitis B treated with lamivudine

Lamivudine resistance has been described in subjects with chronic hepatitis B infections, associated with mutations in the viral polymerase gene. The objective of this study was to estimate the emergence rate of lamivudine-resistant viral strains and their consequences over a 2-year period. We evaluated 283 lamivudine-naïve subjects with chronic hepatitis B. Clinical and virological features were assessed at inclusion and every 6 months thereafter. Viral DNA was characterized using polymerase chain reaction (PCR)-based sequencing. Potential risk factors for the emergence of lamivudine resistance mutations were assessed using logistic regression analysis. The annualized incidence rate for viral polymerase mutations was 22%. The only independent risk factor identified was high viral load, at inclusion. Detectable viral DNA and elevated transaminases were more frequent in subjects harbouring mutant viral strains, and these underwent a lower rate of hepatitis B e seroconversion. All subjects responded favourably to treatment, with no difference in symptoms between the two groups. This prospective cohort study identified lamivudine-resistant mutations emerging in 22% of subjects, yearly, which were apparently not associated with clinical aggravation over the study period.

Selecting appropriate management strategies for chronic hepatitis B: who to treat

BACKGROUND

Hepatitis B virus (HBV) infection is a significant problem. In the United States estimates indicate that 0.3% of the population (1.25 million individuals) have chronic hepatitis B infection.

METHODS

Review of published practice guidelines and literature on management of hepatitis B to determine: 1) Which persons in Western populations are at the highest risk for HBV infection and should be screened for HBV seromarkers to identify those who are chronically infected and those who need to be protected with hepatitis B vaccine; 2) The importance of regular monitoring in persons with chronic hepatitis B, the frequency of monitoring, and which tests should be performed; 3) How to identify the patients who are appropriate candidates for antiviral therapy.

RESULTS

Recommendations for screening, diagnosis, monitoring, and treatment of chronic HBV infection are reviewed. Important differences are discussed between the Practice Guidelines for chronic hepatitis B developed by the American Association for the Study of Liver Diseases (AASLD), the European Association for the Study of the Liver (EASL), and the Asian Pacific Association for the Study of the Liver (APASL). In addition, this article reviews which patients who are no covered by these Guidelines might be candidates for antiviral therapy.

DISCUSSION

Established practice guidelines provide direction to providers for the diagnosis and management of chronic HBV infection to reduce the risk of serious sequelae. However, not all patients with chronic hepatitis B are identified, and many of those who are diagnosed do not receive adequate management and follow-up.

Natural history of chronic hepatitis B virus infection: what we knew in 1981 and what we know in 2005

Remarkable progress has been made in our understanding of the natural history of chronic hepatitis B virus (HBV) infection in the past 25 years. Availability of sensitive HBV DNA assays and application of sophisticated immunological techniques led to the recognition that HBV replication persists throughout the course of chronic HBV infection, and host immune response plays a pivotal role in HBV-related liver disease. Knowledge of the HBV genome organization and replication cycle led to the unraveling of HBV genotypes and molecular variants, which contribute to the heterogeneity in outcome of chronic HBV infection. The natural course of chronic HBV infection is now perceived as consisting of 4 phases: immune tolerance, immune clearance [hepatitis B e antigen (HBeAg)-positive chronic hepatitis], inactive carrier state, and reactivation (HBeAg-negative chronic hepatitis B). Understanding the dynamic nature of chronic HBV infection is crucial in the management of HBV carriers and underscores the need for long-term monitoring. Accumulating evidence indicates that antiviral therapy can prevent progression of HBV-related liver disease, particularly among patients with sustained response. Newer antiviral therapies with improved efficacy and decreased risk of resistance may lead to a complete revision of the chapter on the natural history of chronic HBV infection on the occasion of the golden jubilee of Hepatology.

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.

Hepatitis B virus genotypes, core promoter variants, and precore stop codon variants in patients infected chronically in North-Eastern Italy

The hepatitis B virus (HBV) genotypes distribution and the core promoter (CP)/precore (PC) variability were evaluated by a line probe assay in 272 patients infected chronically enrolled consecutively in an area of the North-Eastern Italy. Seven out of the eight genotypes were detected. Italian subjects (83% of the sample) were infected mainly by genotype D (73%) and A (26%); genotype F, and genotype H, were detected only in one subject. In foreigners, the genotype distribution reflected the distribution described for the areas of origin, that is, in Asia genotypes B, C, and D; in Africa genotypes A and E. CP and PC variants prevalence rates were 51% and 60%, respectively, and were significantly higher in Italian patients, probably in relation to their older age. In the analysis restricted to genotypes A and D, PC wild type was linked strongly to genotype A (OR = 4.08, 95% CI = 3.07-5.43, P < 0.0001). In genotype A-infected patients, only e seroconversion was associated significantly with CP variants. In genotype D-infected subjects, CP variants were linked significantly to older age and to a higher e seroconversion rate, while PC variants also showed a strong relationship with an ALT lower activity and a lower viral load. In multivariate analysis, HBeAg positivity was associated strongly and independently with younger age, genotype A and CP wild type. Independent determinants of higher viral loads were recognized by increasing age, in male gender and concomitant presence of HBeAg and the CP wild type virus.

Hepatitis B virus (HBV) DNA levels and the management of HBV-infected health care workers

Different guidelines exist for the management of hepatitis B virus (HBV)-infected health care workers (HCWs). Various HBV DNA levels are used as a cutoff level to determine whether an HBV-infected HCW is allowed to perform exposure-prone procedures (EPPs) or not. In this paper we discuss the factors that determine HBV DNA levels and the implications of different HBV DNA cutoff levels for EPP performing HCWs. If the level of HBV DNA in the serum of HCWs is used to determine acceptability for the conduct of EPPs, it is necessary to take into account the variability in time of HBV DNA levels in HBV carriers and the reliability and reproducibility of the molecular diagnostic test involved. The issue of standardization has to be addressed, before a universal, maximum level of viraemia for EPP performing HCWs can be introduced.

Hepatitis B virus genome variability and disease progression: the impact of pre-core mutants and HBV genotypes

The hepatitis B virus (HBV), a member of the Hepadnaviridae family, is prone to mutations due to its asymmetric replication via reverse transcription of an RNA intermediate. The estimated mutation rate of the hepadnavirus genome is 2 x 10(4) base substitutions/site/year. This mutation rate is approximately 100 times higher than that of other DNA viruses but between 100 and 1000 times lower than that of RNA viruses. Analyses of both naturally occurring viral variants and in vitro mutagenesis studies have identified some mutations that have a role in viral latency, pathogenesis of liver disease, immune escape, and resistance to antiviral therapy.

Chronic Hepatitis B and Viral Genotype: The Clinical Significance of Determining HBV Genotypes

The global health challenge posed by the hepatitis B virus (HBV) centres around the widespread distribution and the serious complications as a result of persistent infection with the virus. As with other chronic diseases mediated by pathogens such as human immunodeficiency virus (HIV) and hepatitis C virus (HCV), clinicians are searching for epidemiological, pathological and viral characteristics of HBV infection that may lead to more effective management of patients with chronic infection. Unlike HCV, the role of HBV genotype in disease progression, severity, response to therapy and drug resistance is still under investigation and just beginning to be clarified. This review examines the potential role of HBV genotype determination in the clinic with emphasis on how this genetic information may used to provide effective management for the treatment of patients with chronic hepatitis B.

Epidemiology of hepatocellular carcinoma

Year 2000 estimates of the incidence of cancer indicate that primary liver cancer remains the fifth most common malignancy in men and the eighth in women. The number of new cases has been predicted as 564,000, corresponding to 398,000 in men and 166,000 in women. The geographic areas at highest risk are located in Eastern Asia, Middle Africa, and some countries of Western Africa. Changes in incidence among migrant populations underline the predominant role of environmental factors in the etiology of primary liver cancer. In high-risk countries, the early cases of primary liver cancer occur already at ages 20 and above, underlying the impact of viral exposures early in life. In countries at low risk, primary liver cancer is rare before the 50s, translating the impact of late exposures with moderate risks and long latency intervals. Sex ratios are typically between 2 and 4. The incidence of primary liver cancer is increasing in several developed countries including the United States, and the increase will likely continue for several decades. The trend has a dominant cohort effect related to exposures to hepatitis B and C viruses. The variability of primary liver cancer incidence is largely explained by the distribution and the natural history of the hepatitis B and C viruses. The attributable risk estimates for the combined effects of these infections account for well over 80% of liver cancer cases worldwide. Primary liver cancer is the first human cancer largely amenable to prevention using hepatitis B virus vaccines and screening of blood and blood products for hepatitis B and C viruses.

Clinical and molecular characterization of chronic hepatitis B in Albania: a country that is still highly endemic for HBV infection

Albania is a Mediterranean country, still with a high endemicity level of hepatitis B virus (HBV) infection. The chronic hepatitis B profile was characterized in this geographical area and used as a model to investigate the impact of endemicity level on the prevalence of the two major forms of chronic hepatitis B (HBeAg-positive and HBeAg-negative chronic hepatitis B). A cross-sectional study was conducted among 62 chronic hepatitis B patients consecutively admitted to the most important tertiary health care center for the diagnosis and treatment of liver disease in Albania. HBV-DNA was measured with an in-house PCR with a sensitivity of 10(4) copies/ml which uses primers encompassing the pre-core/core region. PCR products were subjected to sequencing and oligohybridization assay. Of the 62 patients, 75.8% had HBeAg-negative chronic hepatitis B. Genotype D was found in all 39 patients with detectable HBV viremia, for whom the heterogeneity of the region modulating HBeAg expression was assessed. Basic core promoter (BCP) mutations (1762/1764) were observed more often in anti-HBe-positive and older patients. In more than 90% of the HBeAg-negative chronic hepatitis B patients with detectable viremia, HBV that carries the G to A pre-core mutation at nucleotide 1896 was found. Patients with HBeAg-positive chronic hepatitis B were younger than HBeAg-negative chronic hepatitis B patients, and for symptomatic and asymptomatic liver-disease patients, the age of peak prevalence was at least 10 years lower for HBeAg-positive chronic hepatitis B patients. In conclusion, the virological and clinical pattern of chronic hepatitis B in Albania is similar to that observed in other Mediterranean countries; it seems to be independent of the HBV endemicity level.

Clinical outcome and virological characteristics of hepatitis B-related acute liver failure in the United States

The role of hepatitis B virus (HBV) genotypes in the outcome of acute HBV infection is unclear. In this study, we aimed to evaluate the clinical and virological features of patients with hepatitis B-related acute liver failure (HBV-ALF) in the US. Clinical and laboratory features of consecutive patients with HBV-ALF from the US ALF Study Group were analysed. Prevalence of HBV genotypes, precore stop (G1896A) and core promoter dual (T1762A, A1764T) variants among patients with HBV-ALF were compared with a cohort of 530 patients with chronic HBV infection. Thirty-four HBV-ALF patients were studied: mean age 41 years, 56% men, 25 had detectable HBV-DNA. HBV genotypes A, B, C and D were found in 36, 24, 8 and 32% patients, respectively. Precore stop and core promoter dual variants were detected in 32 and 44% of patients, respectively. Twenty-three (68%) patients survived: 14 after liver transplant, nine without transplant. Older age was the only independent factor associated with poor outcome. Compared with patients with chronic HBV infection, patients with ALF were more likely to be non-Asians (88% vs 44%, P = 0.005) and to have genotype D (32% vs 10%, P < 0.01). A higher prevalence of HBV genotype D persisted even after matching for race and HBeAg status (32% vs 16%, P = 0.007). We concluded that HBV genotype D was more frequently found in patients with HBV-ALF than those with chronic HBV infection in the US. Further studies are needed to determine if HBV genotypes play a role in the outcome of acute HBV infection.

In vitro resistance to interferon of hepatitis B virus with precore mutation

AIM: Chronic hepatitis B virus (HBV) infection is predominantly treated with interferon alpha (IFN-α), which results in an efficient reduction of the viral load only in 20-40% of treated patients. Mutations at HBV precore prevail in different clinical status of HBV infection. The roles of precore mutation in the progression of chronic hepatitis and interferon sensitivity are still unknown. The aim of this study was to explore if there was any relationship between HBV precore mutation and sensitivity to interferon in vitro.

METHODS: HBV replication-competent recombinant constructs with different patterns of precore mutations were developed. Then the recombinants were transiently transfected into hepatoma cell line (Huh7) by calcium phosphate transfection method. With or without IFN, viral products in culture medium were collected and quantified 3 d after transfection.

RESULTS: We obtained 4 recombinant constructs by orientation-cloning 1.2-fold-overlength HBV genome into pUC18 vector via the EcoRI and Hind III and PCR mediated site-directed mutagenesis method. All the recombinants contained mutations within precore region. Huh7 cells transfected with recombinants secreted HBsAg and HBV particles into the cell culture medium, indicating that all the recombinants were replication-competent. By comparing the amount of HBV DNA in the medium, we found that HBV DNA in medium reflecting HBV replication efficiency was different in different recombinants. Recombinants containing precore mutation had fewer HBV DNAs in culture medium than wild type. This result showed that recombinants containing precore mutation had lower replication efficiency than wild type. HBV DNA was decreased in pUC18-HBV1.2-WT recombinants after IFN was added while others with precore mutations were not, indicating that HBV harboring precore mutation was less sensitive to IFN in cell culture system.

CONCLUSION: These data indicate that HBV harboring precore mutation may be resistant to IFN in vitro.

Strong association between genotype F and hepatitis B virus (HBV) e antigen-negative variants among HBV-infected argentinean blood donors

A number of reports have indicated an increased risk of cirrhosis and hepatocellular carcinoma in hepatitis B virus (HBV)-infected individuals carrying HBV e antigen (HBeAg)-negative variants. Although distinct core promoter and precore mutations distributed according to geographical locality and viral genotype have been reported, epidemiological data from South America are still scarce. The prevalences of HBV genotypes and core promoter and precore polymorphisms in 75 HBeAg-negative Argentinean blood donors were surveyed. The observed frequencies of HBV genotypes were 64.0% for genotype F, 17.3% each for genotypes A and D, and 1.3% for genotype C. Genotype F strains were widely distributed and significantly more prevalent in the northern region of the country (P < 0.001). An overall high proportion of a stop codon mutation (UAG) at precore codon 28 (66.7%) was observed. Wild-type codon 28 (UGG) was present in 29.3% of the samples, and the remaining 4.0% of samples had mixed variants. The combination of A at nucleotide (nt) 1762 and G at nt 1764 of the core promoter was found in 58.7% of the samples. The variant profiles--T at nt 1762 and A at nt 1764 or A at nt 1762 and A at nt 1764--were detected in 28.0 and 1.3% of the samples, respectively. The observed core promoter polymorphisms could not be related to the ratio of HBeAg to anti-HBeAg antibody, HBV genotype, or precore codon 28 status. Nevertheless, a clear association of genotype F and a precore stop codon mutation was found (P < 0.05). In conclusion, HBV genotype F and mutant codon 28 strains predominated and were strongly associated in a geographically broad Argentinean blood donor population.

Natural History and Clinical Consequences of Hepatitis B Virus Infection

Despite the existence of Hepatitis B vaccination, hepatitis B virus (HBV) infection is still prevalent worldwide and accounts for significant morbidity and mortality. It is encouraging that majority of patients do recover from the acute infection, however, those that progress to chronic disease state is at great risk of developing complications such as hepatocellular carcinoma, cirrhosis and liver failure. Hepatitis B virus infection can be influenced by many factors such as host immune status, age at infection, and level of viral replication. The discovery about the existence of various genotypes and its association with different geographic distribution as well as the knowledge regarding mutant species has aid us in better understanding the nature of HBV infection and in delivering better care for patients. It is especially important to recognize those individuals with HBeAg-negative chronic HBV as they have a poorer prognosis compare with their counterparts, HBeAg-positive. Tremendous progress has been made over the years in understanding the behavior and clinical course of the disease; however, the natural history of HBV is complex and we still have much to explore and learn.

Development of a molecular-beacon assay to detect the G1896A precore mutation in hepatitis B virus-infected individuals

The 1896 precore (PC) mutation is the most frequent cause of hepatitis B virus e-antigen (HBeAg)-negative chronic hepatitis B virus (HBV) infection. Detection of the 1896 PC mutation has application in studies monitoring antiviral therapy and the natural history of the disease. Identification of this mutation is usually performed by direct sequencing, which is both costly and laborious. The aim of this study was to develop a rapid, high-throughput assay to detect the 1896 PC mutation using real-time PCR and molecular-beacon technology. The assay was initially standardized on oligonucleotide targets and plasmids containing the wild-type (WT) and PC mutation and then tested on plasma samples from children with HBV DNA of >10(6) copies/ml. Nine individuals were HBeAg negative and suspected to harbor HBeAg mutations, while 12 children were HBeAg positive and selected as controls. Ninety percent (19 of 21) of plasma samples tested with molecular beacons were in complete agreement with sequencing results. The remaining 10% (2 of 21) of samples were identified as heterogeneous mixtures of WT and mutant virus by molecular beacons, though sequencing found only a homogeneous mutant in both cases. Overall, the 1896 PC mutation was detected by this assay in 55.5% of the children with HBeAg-negative infection. In summary, this assay is a rapid, sensitive, and specific technique that effectively discriminates WT from 1896 PC mutant HBV and may be useful in clinical and epidemiological studies.

Chronic hepatitis B

Interferon alpha, lamivudine, and adefovir are the three drugs currently approved for the treatment of chronic hepatitis B virus (HBV). There are pros and cons associated with the use of each drug. Individualization of therapy, based upon factors such as patient comorbidities, response to prior therapies, and stage of disease, is recommended. Patients with abnormal liver enzymes, indices of active viral replication (HBV DNA positive hepatitis B early antigen positive) or evidence of necroinflammatory activity on liver biopsy, and compensated liver disease are potential candidates for treatment with interferon, lamivudine, or adefovir. Patients with abnormal liver enzymes, indices of active viral replication (HBV DNA positive HB(e)Ag positive), and decompensated liver disease are candidates for treatment with lamivudine or adefovir. Consideration of liver transplantation should occur concurrently. Interferon alpha treatment results in hepatitis B surface antigen loss and sustained suppression of HBV DNA replication in 30% to 40% of treated patients. Loss of HBsAg occurs in nearly 10% of patients and a higher than expected frequency of HBsAg loss occurs long-term. The main limitation of therapy is the side effects and the need for parenteral administration. Additionally, interferon therapy is not applicable to all patient groups. Lamivudine achieves HB(e)Ag seroconversion in 15% to 20% of patients treated for 12 months, but (HBsAg) loss is rare. Reduction in HBV DNA to undetectable levels (by hybridization assay) during treatment is nearly universal, and histologic improvement is seen in about 55% of patients. The main limitation of lamivudine therapy is the development of drug resistance, which occurs in 20% of patients after 12 months and increases with duration of therapy (55% at 3 years). Adefovir achieves HB(e)Ag seroconversion in 12% of patients treated for 12 months, but HBsAg loss is rare. An average 3.5 log reduction in HBV DNA levels is and histologic improvement occurs in 50% to 60% of patients. It is effective against both wild-type and lamivudine-resistant HBV. The risk of drug resistance is low and estimated to be approximately 2% to 3% after 2 years of treatment. Several new antiviral agents are currently under evaluation in clinical trials. In addition, there are two drugs (tenofovir and emtricitabine) that have been approved for HIV infection and that have anti-HBV activity. In the future, combination therapy for chronic HBV infection can be anticipated. Utilization of two or more anti-HBV drugs would be predicted to enhance efficacy and reduce the likelihood of emergence of drug resistance.

Global epidemiology of hepatitis B virus

The burden of hepatitis B virus (HBV) disease and efforts to control infection will determine the future size of the population requiring treatment of HBV infection. To quantify the current prevalence of HBV infection and to reexamine the epidemiology of HBV infection, a structured review was conducted that focused on available primary literature for over 30 countries worldwide. The prevalence of chronic HBV infection continues to be highly variable, ranging over 10% in some Asian and Western Pacific countries to under 0.5% in the United States and northern European countries. The current global estimate of the number of HBV infected individuals is 350 million. Routes of transmission include vertical (mother to child or generation to generation through close contact and sanitary habits), early life horizontal transmission (through bites, lesions, and sanitary habits), and adult horizontal transmission (through sexual contact, intravenous drug use, and medical procedure exposure) and are evident to varying degrees in every country. Younger age at acquisition of infection continues to be the most important predictor of chronic carriage. However, the choice of serologic markers, temporal influences, and representativeness of the study population limit comparability of HBV seroprevalence results. HBV vaccination programs will decrease the future global burden of HBV infection and evidence of reduced burden is mounting in country-specific populations, but vaccination programs have still not been implemented in all countries, thereby maintaining reservoirs of infection and continued HBV transmission. Regardless of vaccination, large numbers of persons are infected with HBV or will become infected. Preventing the most severe HBV disease consequences in infected individuals, such as cirrhosis and hepatocellular carcinoma, will require appropriate therapeutic agents.

Primary liver cancer: worldwide incidence and trends

Estimates from the year 2000 indicate that liver cancer remains the fifth most common malignancy in men and the eighth in women worldwide. The number of new cases is estimated to be 564,000 per year, including 398,000 in men and 166,000 in women. In high-risk countries, liver cancer can arise before the age of 20 years, whereas, in countries at low risk, liver cancer is rare before the age of 50 years. Rates of liver cancer in men are typically 2 to 4 times higher than in women. The incidence of primary liver cancer is increasing in several developed countries, including the United States, and the increase will likely continue for some decades. The trend is a result of a cohort effect related to infection with hepatitis B and C viruses, the incidence of which peaked in the 1950s to 1980s. In selected areas of some developing countries, the incidence of primary liver cancer has decreased, possibly as a result of the introduction of hepatitis B virus vaccine. The geographic variability in incidence of primary liver cancer is largely explained by the distribution and the natural history of the hepatitis B and C viruses. The attributable risk estimates for the combined effects of these infections account for well over 80% of liver cancer cases worldwide. Primary liver cancer is the first human cancer largely amenable to prevention using hepatitis B virus vaccines and screening of blood and blood products for hepatitis B and C viruses.

Peginterferon alfa-2a alone, lamivudine alone, and the two in combination in patients with HBeAg-negative chronic hepatitis B

BACKGROUND

Available treatments for hepatitis B e antigen (HBeAg)-negative chronic hepatitis B are associated with poor sustained responses. As a result, nucleoside and nucleotide analogues are typically continued indefinitely, a strategy associated with the risk of resistance and unknown long-term safety implications.

METHODS

We compared the efficacy and safety of peginterferon alfa-2a (180 microg once weekly) plus placebo, peginterferon alfa-2a plus lamivudine (100 mg daily), and lamivudine alone in 177, 179, and 181 patients with HBeAg-negative chronic hepatitis B, respectively. Patients were treated for 48 weeks and followed for an additional 24 weeks.

RESULTS

After 24 weeks of follow-up, the percentage of patients with normalization of alanine aminotransferase levels or hepatitis B virus (HBV) DNA levels below 20,000 copies per milliliter was significantly higher with peginterferon alfa-2a monotherapy (59 percent and 43 percent, respectively) and peginterferon alfa-2a plus lamivudine (60 percent and 44 percent) than with lamivudine monotherapy (44 percent, P=0.004 and P=0.003, respectively; and 29 percent, P=0.007 and P=0.003, respectively). Rates of sustained suppression of HBV DNA to below 400 copies per milliliter were 19 percent with peginterferon alfa-2a monotherapy, 20 percent with combination therapy, and 7 percent with lamivudine alone (P<0.001 for both comparisons with lamivudine alone). Loss of hepatitis B surface antigen occurred in 12 patients in the peginterferon groups, as compared with 0 patients in the group given lamivudine alone. Adverse events, including pyrexia, fatigue, myalgia, and headache, were less frequent with lamivudine monotherapy than with peginterferon alfa-2a monotherapy or combination therapy.

CONCLUSIONS

Patients with HBeAg-negative chronic hepatitis B had significantly higher rates of response, sustained for 24 weeks after the cessation of therapy, with peginterferon alfa-2a than with lamivudine. The addition of lamivudine to peginterferon alfa-2a did not improve post-therapy response rates.

Basal core promoter and precore mutations in the hepatitis B virus genome enhance replication efficacy of Lamivudine-resistant mutants

During chronic hepatitis B virus (HBV) infection, mutations in the precore (PC) or basal core promoter (BCP) region affecting HBV e antigen (HBeAg) expression occur commonly and represent the predominant virus species in patients with HBeAg-negative chronic hepatitis B. The PC mutation (G1896A+C1858T) creates a translational stop codon resulting in absent HBeAg expression, whereas BCP mutations (A1762T/G1764A) reduce HBeAg expression by transcriptional mechanisms. Treatment of chronic HBV infection with lamivudine (LMV) often selects drug-resistant strains with single (rtM204I) or double (rtL180M+rtM204V) point mutations in the YMDD motif of HBV reverse transcriptase. We cloned replication-competent HBV vectors (genotype A, adw2) combining mutations in the core (wild type [wt], PC, and BCP) and polymerase gene (wt, rtM204I, and rtL180M/M204V) and analyzed virus replication and drug sensitivity in vitro. Resistance to LMV (rtM204I/rtL180M+rtM204V) was accompanied by a reduced replication efficacy as evidenced by reduced pregenomic RNA, encapsidated progeny DNA, polymerase activity, and virion release. PC mutations alone did not alter virus replication but restored replication efficacy of the LMV-resistant mutants without affecting drug resistance. BCP mutants had higher replication capacities than did the wt, also in combination with LMV resistance mutations. All nine HBV constructs showed similar sensitivities to adefovir. In conclusion, BCP-PC mutations directly impact the replication capacity of LMV-resistant mutants. PC mutations compensated for replication inefficiency of LMV-resistant mutants, whereas BCP mutations increased viral replication levels to above the wt baseline values, even in LMV-resistant mutants, without affecting drug sensitivity in vitro. Adefovir may be an effective treatment when combinations of core and polymerase mutations occur.

Antiviral therapy for treatment-naïve hepatitis B virus patients

Hepatitis B virus infection is a major public health problem worldwide,responsible for considerable morbidity and mortality from chronic liver disease. It is estimated that there are 350 million hepatitis B virus carriers globally. The prevalence of chronic hepatitis B infection varies greatly in different regions of the world. In the United States, approximately 1.5 million people are infected and 50,000 to 100,000 new cases are reported annually despite the availability of effective vaccines. This article reviews various antiviral therapies for treatment naïve hepatitis B virus patients.

Eight genotypes (A-H) of hepatitis B virus infecting patients from San Francisco and their demographic, clinical, and virological characteristics

Clinical lines of evidence have been accumulated that hepatitis B virus (HBV) genotypes have characteristic geographical distributions and distinct clinical impact on liver diseases. The distribution of HBV genotypes was determined with reference to hepatitis B e antigen (HBeAg) and alanine aminotransferase (ALT) levels in 165 patients with hepatitis B in San Francisco. HBV genotypes were determined by enzyme-linked immunosorbent assay (ELISA) and the unclassified samples were sequenced within the S region for phylogenetic analysis. Genotype A occurred in 60 (36%) patients, B in 16 (10%), C in 56 (34%), D in 19 (12%), E in 1 (1%), F in 1 (1%), G in 8 (5%), and H in 4 (2%). Caucasians were infected predominantly with HBV genotype A (HBV/A) (38 of 57 [67%]), Asians with HBV/C (45 of 63 [71%]), and Hispanics with HBV/F and HBV/H (4 of 9 [44%]). Serum ALT levels were higher in the patients infected with HBV/A (P = 0.03) or HBV/G (P = 0.02) than HBV/C. HBeAg was more frequent in patients infected with HBV/G than HBV/C or HBV/D (7 of 8 [88%] vs. 25 of 56 [45%] or 6 of 19 [32%], P = 0.03 or 0.01). In conclusion, eight genotypes (A-H) were identified in San Francisco in association with various ethnicities and then influenced ALT levels as well as the prevalence of serum HBeAg. HBV genotype H might be identified by combination of preS2 serotpe bksf and HBsAg serotype adw.

Usefulness of dried blood samples for quantification and molecular characterization of HBV-DNA

The purpose of this study was to assess the use of dried blood spot (DBS) samples for hepatitis B virus (HBV) DNA quantification, HBV genotyping, and detection of G1896A precore mutants and variants in the YMDD polymerase motif. We studied DBS and serum samples from 82 patients with chronic HBV infection (23 hepatitis B e antigen [HBeAg]-positive and 39 HBeAg-negative), 20 HBeAg-inactive carriers, and 15 HBeAg-negative patients under lamivudine therapy (selected from chronic HBV patients). DBS samples consisted of approximately 20 microL of blood applied to 5-mm paper disks. HBV DNA quantification and HBV precore mutant detection were done using real-time polymerase chain reaction, HBV genotyping using restriction fragment length polymorphism, and YMDD variant detection by Inno-lipa assay. DBS and serum results were compared. HBV DNA was detected in a range of 10(2)-10(8) copies/mL, with low intra-assay and inter-assay variation (<10%). Median DBS HBV DNA (copies/mL) was: 3.7 x 10(6) in HBeAg-positive, 6.2 x 10(5) in HBeAg-negative, and 5.5 x 10(2) in inactive carriers (P <.05). HBV DNA was positive in serum (median 5 x 10(3) copies/mL) but negative in DBS for five inactive carriers. The correlation coefficient between HBV DNA concentration in DBS versus serum samples was r(2) = 0.96 (P <.001). The sensitivity of HBV DNA detection in DBS samples was 1 log(10) lower than in serum samples. Concordance between DBS and serum for HBV genotyping, and for precore mutant and YMDD variant detection was optimal. DBS storage for 7 days at room temperature and 21 days at -20 degrees C revealed no decrease in HBV DNA levels or integrity. In conclusion, the DBS sample is useful for HBV DNA quantification, genotyping, and detection of precore mutant and YMDD variants. All four determinations can be completed with a single drop of dried blood.

Viral hepatitis in 2003

PURPOSE OF REVIEW

This article discusses over 40 studies in the field of viral hepatitis that were published in 2003. Studies that reported novel findings of clinical relevance were selected after a MEDLINE search. This article focuses on hepatitis B and hepatitis C.

RECENT FINDINGS

In the United States, all genotypes of hepatitis B virus were reported, and precore and core promoter mutations were found in approximately a third of patients. The response to lamivudine was less durable than that induced by interferon. Adefovir dipivoxil was safe and effective for treatment-naive patients as well as for lamivudine-resistant patients. In acute hepatitis C infection, close monitoring of hepatitis C virus RNA and treatment of patients with persistent viremia is a reasonable alternative to immediate treatment of all patients. Noninvasive indices to predict liver fibrosis are currently being tested. Failure to achieve an early virologic response to pegylated interferon plus ribavirin can identify more than 95% patients who will not have a sustained response.

SUMMARY

The clinical significance of hepatitis B virus genotypes and viral variants continues to be elucidated worldwide. Long-term lamivudine treatment is safe, despite a rising rate of resistance. Adefovir appears to be safe and effective as initial therapy for chronic hepatitis B virus infection or for the management of lamivudine-resistant hepatitis B infection. Noninvasive indices for liver fibrosis require validation but may reduce the need for liver biopsy in the future. Newer agents for the treatment of hepatitis C virus infection show promise.

Hepatitis B: epidemiology and natural history

Chronic infection with hepatitis B and its sequelae remains a major global health concern. Despite recommendations and implementation of vaccination programs, the health and economic burdens are still significant. People in endemic areas and immigrants from these areas need to be adequately screened and treated. HBeAg-negative chronic hepatitis is increasingly recognized with additional challenges in management. Programs implementing primary prophylaxis strategies such as vaccination of high-risk adult and adolescent groups should continue.