Rapid and sensitive assays for determination of hepatitis B virus (HBV) genotypes and detection of HBV precore and core promoter variants

Hepatitis B virus preS2Δ38-55 variants: A newly identified risk factor for hepatocellular carcinoma

BACKGROUND & AIMS

Although HBV is a major cause of death in Africa, its genetic variability has been poorly documented. This study aimed to address whether HBV genotype and surface gene variants are associated with HBV-related liver disease in The Gambia.

METHODS

We conducted a case-control study nested in the Prevention of Liver Fibrosis and Cancer in Africa programme. Consecutive treatment-naive patients with chronic HBV infection and detectable viral load were recruited: 211 controls with no significant liver disease and 91 cases (56 cirrhosis and 35 HCC cases). HBV genotypes and surface gene variants were determined by Sanger sequencing or next-generation sequencing (NGS) in serum DNA. Aflatoxin B1 (AFB1)-specific codon 249 TP53 mutation was determined by NGS in circulating cell-free plasma DNA.

RESULTS

In phylogenetic analysis, 85% of individuals carried HBV genotype E, 14% genotype A, and 1% A/E recombinant viruses. Surface gene variants were more frequently observed in cases (43% and 57% in cirrhosis and HCC cases, respectively) than controls (25%; p <0.001), with preS2 deletions between nucleotides 38-55 (preS2Δ38-55) being the main genetic variant detected. In multivariable analysis, HBeAg seropositivity, low HBsAg levels, and HDV seropositivity were significantly associated with cirrhosis and HCC, whilst older age, higher viral load, genotype A, preS2Δ38-55, and AFB1 exposure were only associated with HCC. There was a multiplicative joint effect of preS2Δ38-55 variants with HBeAg seropositivity (odds ratio [OR] 43.1 [10.4-177.7]), high viral load >2,000 IU/ml (OR 22.7 [8.0-64.9]), HBsAg levels <10,000 IU/ml (OR 19.0 [5.5-65.3]), and AFB1 exposure (OR 29.3 [3.7-230.4]) on HCC risk.

CONCLUSIONS

This study identified a hotspot for HBV preS2 deletions as a strong independent factor for HCC in The Gambia, with HBV genotypes and AFB1 exposure contributing to the high liver cancer risk.

LAY SUMMARY

Although HBV-related liver disease is highly prevalent in sub-Saharan Africa, the associated virological characteristics are poorly studied. Using clinical data from African patients chronically infected with HBV, an assessment of the virological variability (genotypes and mutations) and exposure to AFB1, a toxin often contaminating food, was carried out. Our results show that HBV genotypes, the presence of a highly prevalent mutant form of HBV, and AFB1 exposure contribute to the high liver cancer risk in this population.

A short note on HBV infection

HBV-related liver sickness or hepatocellular carcinoma is common worldwide. Therefore, it is of interest to document the current trends in hepatitis prevention, diagnosis, treatment and care.

Molecular signature of hepatitis B virus regulation by interferon-γ in primary human hepatocytes

AIM

A complete cure for chronic hepatitis B virus (HBV) infection requires elimination of covalently closed circular DNA; however, this remains to be clinically achieved. Interferon (IFN)-γ, a type II IFN, is produced by intrahepatic cytotoxic T lymphocytes and has non-cytolytic antiviral potential. However, the mechanism by which IFN-γ regulates HBV infection has not been fully elucidated. Thus, we developed an in vitro HBV infection assay system and analyzed the molecular signature of HBV regulation by IFN-γ.

METHODS

The in vitro HBV infection assay system was established in primary human hepatocytes infected with HBV derived from the plasmid containing 1.3-mer HBV genome, and treated with IFN-γ. The antiviral effects and signaling pathways of IFN-γ were examined using microarray, and assessed by siRNA knockdown experiments of the related genes.

RESULTS

IFN-γ treatment suppressed both HBV propagation and transcription as efficiently as IFN-α. Microarray analysis showed that IFN-γ stimulation induced the activation of both IFN-γ and IFN-α signaling, regulating HBV covalently closed circular DNA. HBV production was decreased by IFN-γ through Janus kinase/signal transducer and activator of transcription signaling and interferon-stimulated genes, such as 2'-5'-oligoadenylate synthase 2 and apolipoprotein B mRNA editing enzyme catalytic subunit 3G.

CONCLUSIONS

IFN-γ can suppress HBV propagation and transcription in hepatocytes by activating specific intracellular signaling pathways in hepatocytes, and suggests the future application of these particular signaling pathways or genes for the complete elimination of HBV.

Molecular Microbiology

Background

Nucleic acid (NA) amplification techniques are now commonly used to diagnose and manage patients with infectious diseases. The growth in the number of Food and Drug Administration–approved test kits and analyte-specific reagents has facilitated the use of this technology in clinical laboratories. Technological advances in NA amplification techniques, automation, NA sequencing, and multiplex analysis have reinvigorated the field and created new opportunities for growth. Simple, sample-in, answer-out molecular test systems are now widely available that can be deployed in a variety of laboratory and clinical settings. Molecular microbiology remains the leading area in molecular pathology in terms of both the numbers of tests performed and clinical relevance. NA-based tests have reduced the dependency of the clinical microbiology laboratory on more traditional antigen detection and culture methods and created new opportunities for the laboratory to impact patient care.

Content

This chapter reviews NA testing as it applies to specific pathogens or infectious disease syndromes, with a focus on those diseases for which NA testing is now considered the standard of care and highlights the unique challenges and opportunities that these tests present for clinical laboratories.

Nationwide overview of the distribution of hepatitis B virus genotypes in Brazil: a 1000-sample multicentre study

The influence of hepatitis B virus (HBV) genotypes in the natural history of the disease and its response to antiviral treatment have been addressed in many studies. In Brazil, studies on HBV genotype circulation have been restricted to specific population groups and states. Here, we have conducted a nationwide multicentre study with an unprecedented sample size representing all Brazilian regions in an effort to better understand the viral variants of HBV circulating among chronic carriers. Seven HBV genotypes were found circulating in Brazil. Overall, HBV/A was the most prevalent, identified in 589 (58.7 %) samples, followed by HBV/D (23.4 %) and HBV/F (11.3 %). Genotypes E, G, C and B were found in a minor proportion. The distribution of the genotypes differed markedly from the north to the south of the country. While HBV/A was the most prevalent in the North (71.6 %) and Northeast (65.0 %) regions, HBV/D was found in 78.9 % of the specimens analysed in the South region. HBV/F was the second most prevalent genotype in the Northeast region (23.5 %). It was detected in low proportions (7 to 10 %) in the North, Central-West and Southeast regions, and in only one sample in the South region. HBV/E was detected in all regions except in the South, while monoinfection with HBV/G was found countrywide, with the exception of Central-West states. Our sampling covered 24 of the 26 Brazilian states and the Federal District and is the first report of genotype distribution in seven states. This nationwide study provides the most complete overview of HBV genotype distribution in Brazil to date and reflects the origin and plurality of the Brazilian population.

Hepatitis Viruses B and D and Human Immunodeficiency Virus Infections in Hemodialysis Patients in the South of Iran: Prevalence and Genotypes

BACKGROUND

Hepatitis B virus (HBV), hepatitis D virus (HDV), and human immunodeficiency virus (HIV) are transmitted by blood transfusion. Thus, hemodialysis (HD) patients are more prone to become the carriers of these infections due to their treatment demands.

OBJECTIVES

The aim of this study was to assess the prevalence of HBV and HIV infections among HD patients in Bandar Abbas, Iran, 2015.

PATIENTS AND METHODS

A total of 153 patients with chronic renal failure undergoing HD at Shahid Mohammadi hospital in Bandar Abbas were examined for hepatitis B surface antigen (HBsAg), anti- hepatitis C virus, and anti-HIV over a period of 2 months. Thereafter, all of the specimens were evaluated for HBV-DNA, HDV-RNA and HIV-RNA using polymerase chain reaction (PCR) and further techniques. All statistical analyses were carried out using SPSS version 12 for Windows with the t-test and chi-square (χ(2)) test.

RESULTS

Both kinds of assay determined that nine (5.88%) patients were HBV positive (HBsAg-positive), whereas no HIV- and HDV-positive patients were diagnosed. All of the diagnosed HBV samples belonged to genotype D; the prevalence of HBV is associated with age, duration of HD, history of blood transfusion, and using shared HD devices.

CONCLUSIONS

In conclusion, the prevalence of HBV infection was low in the south of Iran, but genotype D represented the major HBV genotype in this population. Among the variables, age, duration of HD, history of blood transfusion, and using shared HD devices influenced the prevalence of HBV among HD patients.

A Treatment Algorithm for the Management of Chronic Hepatitis B Virus Infection in the United States: 2015 Update

Chronic hepatitis B (CHB) continues to be an important public health problem worldwide, including in the United States. An algorithm for managing CHB was developed by a panel of United States hepatologists in 2004 and subsequently updated in 2006 and 2008. Since 2008, additional data on long-term safety and efficacy of licensed therapies have become available and have better defined therapeutic options for CHB. The evidence indicates that potent antiviral therapy can lead to regression of extensive fibrosis or even cirrhosis, thus potentially altering the natural history of CHB. In addition, appropriate choice of antiviral agent can minimize the risk of resistance. This updated algorithm for managing CHB is based primarily on evidence from the scientific literature. Where data were lacking, the panel relied on clinical experience and consensus expert opinion. The primary aim of antiviral therapy for CHB is durable suppression of serum hepatitis B virus (HBV) DNA to low or undetectable levels. CHB patients who have HBV DNA >2000 IU/mL, elevated alanine aminotransferase level, and any degree of fibrosis should receive antiviral therapy regardless of their hepatitis B e antigen status. CHB patients with HBV DNA >2000 IU/mL and elevated alanine aminotransferase level but no evidence of fibrosis may also be considered for antiviral therapy. Approved antiviral therapies for CHB are interferon alfa-2b, peginterferon alfa-2a, lamivudine, adefovir, entecavir, telbivudine, and tenofovir, although the preferred first-line treatment choices are peginterferon alfa-2a, entecavir, and tenofovir. In determining choice of therapy, considerations include efficacy, safety, rate of resistance, method of administration, duration, and cost.

Precore/Core promoter variants to predict significant fibrosis in both HBeAg positive and negative chronic hepatitis B

BACKGROUND & AIMS

Assessing fibrosis is essential in patients with chronic hepatitis B (CHB). The objective was to investigate the relationship between fibrosis, host and viral factors to identify non-invasive markers of significant fibrosis in a large cohort of unselected, well-characterized, treatment-naïve CHB patients.

METHODS

Three hundred and seventy-seven HBsAg-positive patients (97 HBeAg-positive and 280 HBeAg-negative, genotypes A to E) who had liver biopsy were consecutively included. Host and viral factors (ALT, HBsAg and HBV-DNA levels, HBV genotype and precore (PC)/basal core promoter (BCP) variants) were determined on the day of the biopsy. Fibrosis stage was assessed using METAVIR score.

RESULTS

Thirty-nine percent of the patients had significant fibrosis (METAVIR F ≥ 2). On univariate analysis, the stages of fibrosis F ≥ 2 were associated with older age (P < 0.0001), male gender (P = 0.01), higher ALT and HBV-DNA levels (P < 0.0001 and P = 0.0003, respectively), the presence of BCP (P < 0.0001) and BCP/PC variants (P < 0.0001). On multivariate analysis, age (P < 0.0001), the presence of HBV variants (P < 0.0001), HBV-DNA level (P = 0.0006) and ALT level (P = 0.02) were independently associated with significant fibrosis. The diagnostic accuracy of the combination (age, ALT, HBV-DNA, HBV variants) in predicting fibrosis F ≥ 2 was evidenced by a c-index of 0.76 (CI 95% 0.71-0.81).

CONCLUSIONS

We identified strong independent risk factors (age, ALT, HBV-DNA, HBV variants) predicting significant fibrosis (F ≥ 2) independently of HBeAg status in patients with CHB. Patients with BCP variants have a higher risk of severe liver disease. The detection of these mutants may help to predict significant fibrosis (F ≥ 2).

Retrospective study of the prevalence and clinical significance of hepatitis B virus precore and basal core promoter variants

BACKGROUND

Hepatitis B virus (HBV) precore (PC) and basal core promoter (BCP) variants are well known; however, their prevalence in North America is unclear, especially among hepatitis B e antigen-negative patients.

OBJECTIVE

To investigate the prevalence of PC⁄BCP mutations and their clinical significance.

METHODS

One hundred twenty-eight patients positive for both hepatitis B surface antigen and hepatitis B e antibody were selected, and PC⁄BCP mutations were identified using a line probe assay. The subjects' charts were reviewed for race⁄ethnicity, HBV genotype, HBV viral load, sex, liver enzyme levels, imaging and biopsy results up to 10 years before the study.

RESULTS

The prevalence of PC and BCP variants were 47.6% and 62.5%, respectively. Older age was associated with aspartate aminotransferase-to-platelet index ratio (APRI) ≥0.7 (P=0.011) and abnormal imaging⁄biopsy results (P=0.0008). Although the presence of BCP variant(s) was associated with APRI ≥0.7 (P=0.029), it was not associated with abnormal imaging⁄biopsy results. The combination of age ≥50 years and the presence of BCP variant(s) was associated with abnormal imaging⁄biopsy results, suggestive of either cirrhosis or hepatocellular carcinoma (not observed with PC mutation). Neither sex or genotype, or median HBV viral load showed significant influence on any of these outcomes.

CONCLUSIONS

The present study suggests that the prevalence of PC and BCP mutations are higher than what has been previously reported. One potential explanation would be increased immigration in the past decade. Considering the potential public health and clinical implications of these variants, long-term multicentre and prospective studies could further unravel the uncertainty around these variants.

Genetic characterization and genotyping of hepatitis B virus (HBV) isolates from donors with an occult HBV infection

BACKGROUND AND OBJECTIVES

Screening of Thai blood donors has resulted in the detection of donors with an occult HBV infection (OBI), where HBsAg is undetectable, but hepatitis B virus (HBV) DNA is present in serum in low concentrations. This study was designed to determine whether the occurrence of OBI in donors was linked to the HBV genotype and possibly to mutations in the surface (S) and core (C) gene regions.

MATERIALS AND METHODS

Mutations in the S and C gene regions in 48 Thai donors with OBI were mapped by sequencing. Genotyping was determined with the INNO-LiPA test and by phylogenetic analysis of sequences from the S and C genes.

RESULTS

The majority of OBI samples were genotype C (81·3%) with 6·3% of samples being genotype B. In addition, two genotype I isolates were identified. Mutations in the S region (100%) were found especially in loop 1 of the major hydrophilic loop (MHL) at positions I110L, T114S, T126I and S113T, whereas mutations in the C region (65%) were within the basal core promoter region (position A1762T/G1764A) and precore region (position G1896A).

CONCLUSION

The majority of OBI samples were HBV genotype C, although genotype I, which is newly emerging in Thailand, was also detected. The study demonstrated that OBI was probably not associated with a particular HBV genotype or with certain mutations in the S and C gene regions. However, mutations in the C gene region which could potentially impair viral replication and HBsAg production and potentially lead to OBI were identified.

Molecular epidemiology of hepatitis B virus in Córdoba, Argentina

BACKGROUND

The analysis of the genomes of hepatitis B virus (HBV) identifies phylogenetic variants called genotypes, which may lead to distinct biological and clinical behaviors.

OBJECTIVES

The aim of this study was to describe the current molecular epidemiology and genetic diversity of HBV in Córdoba, Argentina.

STUDY DESIGN

A total of 52 HBV samples, 40 from HBV mono-infected and 12 from human immunodeficiency virus (HIV)-HBV co-infected patients, were sequenced in the S gene and in the basal core promoter-precore (BCP-pC) region.

RESULTS

Presence of subgenotypes F1b (35%) and F4 (17.5%), subgenotype A2 (37.5%), C (5.0%) (subgenotype could not be defined) and D (5.0%) (subgenotype D2, and the other could not be defined) were observed among mono-infected patients. The co-infected individuals displayed a different genotype distribution: sub-genotype A2 was the most common (75.0%), followed by subgenotype F1b (25.0%).

CONCLUSIONS

These results showed two epidemiologic scenarios: the mono-infected population may represent the ethnic composition of the current human population of Córdoba, where the Amerindian (genotype F) and European origins (subgenotype A2) account for the 90% of the samples; for the co-infected patients, the high prevalence of subgenotype A2 resemble previous analyses from Buenos Aires. In addition, mutations in hepatitis B surface antigen (HBsAg), polymerase and BCP-pC regions were identified, mainly in chronic or co-infected patients.

An improved method for simple and efficient hepatitis B virus genome cloning

The genetic variation of hepatitis B virus (HBV) is associated with a natural history of infection and with a response to antiviral therapy. Current attempts to investigate the genetic variation within patients infected with HBV have characterized only the subgenomic region or a limited number of full-length genomes. In this study, a simple and efficient full-length HBV cloning method, which is independent of restriction digestion and ligation, from a clinical sample is presented. The full-length HBV amplified from patients' sera serves as two megaprimers and contains two ends that are homologous to the insertion site of a newly constructed plasmid. This method could enable the extension of the plasmid backbone by DNA polymerase. To improve the cloning efficiency, a LacZ gene fragment was incorporated into the middle of the insertion site in the plasmid and was used for blue-white screening. Through optimization and evaluation, a high success rate of positive clones (90%) from an individual patient was obtained. Thus, this study provides a simple, efficient, and convenient method for full-length HBV cloning from many clinical samples, and this method could greatly facilitate studies concerning the genetic variation of HBV.

Full genome ultra-deep pyrosequencing associates G-to-A hypermutation of the hepatitis B virus genome with the natural progression of hepatitis B

Human APOBEC3 (A3) cytosine deaminases are antiviral restriction factors capable of editing the genome the hepatitis B virus (HBV). Despite the importance of the human A3 protein family for the innate immune response little is known about the clinical relevance for hepatitis B. The aim of this study was to utilize ultra-deep pyrosequencing (UDPS) data to analyse the phenomenon of G-to-A hypermutation of the complete HBV genome and to relate it to fundamental characteristics of patients with chronic hepatitis B. By analysing the viral population of 80 treatment naïve patients (47 HBeAg-positive and 33 HBeAg-negative), we identified an unequal distribution of G-to-A hypermutations across the genome. Our data indicate that G-to-A hypermutation occurs predominantly in a region between nucleotide positions 600 and 1800 a region which is usually single stranded in matured HBV particles. This implies that A3 likely edits HBV in the virion. Hypermutation rates for HBeAg-negative patients were more than 10-fold higher than those of HBeAg-positive patients. For HBeAg-negative patients higher hypermutation rates were significantly associated with the degree of fibrosis. Additionally, we found that for HBeAg-positive chronic hepatitis G-to-A hypermutation rates were significantly associated with the relative prevalence of the G1764A mutation, which is related to HBeAg seroconversion. In total, our data imply an important association of hypermutation mediated by A3 deaminases with the natural progression of chronic hepatitis B infections both in terms of HBeAg seroconversion and disease progression towards cirrhosis.

A novel HBV genotypes detecting system combined with microfluidic chip, loop-mediated isothermal amplification and GMR sensors

Genotyping of hepatitis B virus (HBV) can be used for clinical effective therapeutic drug-selection. A novel microfluidic biochip for HBV genotyping has been fabricated, for the first time, integrating loop-mediated isothermal amplification (LAMP), line probes assay (LiPA) and giant magnetoresistive (GMR) sensors. Coupling LAMP with LiPA in microfluidic chip shortened reaction time substantially, and combining LAMP with GMR sensor enabled limit of detection to attain 10 copies mL(-1) target HBV DNA molecules in 1 h. Furthermore, the independent designed GMR sensors and microfluidic chip can decrease manufacturing cost and patient's test-cost, and facilitate GMR detector repeating use for signal detection. In addition, the detection system has a lower background signal owing to application of superparamagnetic nanoclusters. And it can be expected to use for multiple target molecules synchronous detection in microfluidic chip based on a characteristic of stationary reaction temperature of LAMP. In conclusion, the neoteric detecting system is well suitable for quick genotyping diagnosis of clinical HBV and other homothetic biomolecule detection in biological and medical fields.

Serum levels of interferon-gamma-inducible protein 10 and response to peginterferon therapy in HBeAg-positive chronic hepatitis B

BACKGROUND & AIMS

Serum levels of interferon-gamma inducible protein 10 (IP-10) are a marker for immune activity, and may predict response to peginterferon (PegIFN) therapy in chronic hepatitis B.

METHODS

IP-10 was measured at baseline and on-treatment week 12 in 210 HBeAg-positive patients treated with PegIFN for 52 weeks. Response to treatment was assessed at 6 months post-treatment and defined as HBeAg loss, combined response (HBeAg loss with HBV DNA <10,000 c/ml) or HBsAg loss.

RESULTS

Median baseline IP-10 levels were 158 pg/ml. Higher baseline IP-10 was associated with more HBV DNA, HBeAg and HBsAg decline from week 4 onwards, and IP-10 was higher in patients who achieved HBeAg loss (p=0.001) and combined response (p=0.052). A combination of high IP-10 (>150 pg/ml) with absence of precore (PC) and core promoter (BCP) mutants strongly predicted combined response and HBsAg loss: 48% of patients with high IP-10 and no detectable mutants achieved a combined response (p<0.001). A minimal non-significant decline from baseline was observed to week 12 (0.015 log pg/ml, p=0.52 compared to baseline), but decline was somewhat more pronounced in patients who achieved HBeAg loss (0.05 logpg/ml, versus an increase of 0.05 in patients without HBeAg loss, p=0.04).

CONCLUSIONS

Higher pre-treatment IP-10 levels are associated with an increased probability of HBeAg loss after PegIFN therapy. A combination of high baseline IP-10 and absence of PC and BCP mutants identified patients with the highest probability of combined response and HBsAg loss. There appears little use for on-treatment quantification of IP-10 for prediction of response to PegIFN.

Precore and core promoter mutants are associated with higher HBeAg seroconversion but low disease remission rates in HBV patients treated with nucleos(t)ide analogues

HBeAg seroconversion in HBV patients is considered an important event. We determined precore (PC) and base core promoter (BCP) mutations in 137 HBeAg-positive nucleos(t)ide analogues (NA) treated patients by INNO-LiPA HBV PreCore assay (Innogenetics). The majority of patients with nongenotype A had PC/BCP mutants present at baseline (P = 0.02). During 29 months of therapy, 45 patients achieved HBeAg seroconversion. Probability of HBeAg seroconversion was higher in patients with PC and/or BCP mutants (P = 0.01). After HBeAg seroconversion, patients with BCP mutants had more HBeAg relapse (P = 0.07), and PC mutants less often achieved HBV DNA < 2000 IU/mL (P = 0.07).

Efficacy of tenofovir in patients with Lamivudine failure is not different from that in nucleoside/nucleotide analogue-naive patients with chronic hepatitis B

We evaluated the efficacy of tenofovir disoproxil fumarate (TDF) in patients with lamivudine failure (LAM-F) in comparison with that in nucleoside/nucleotide analogue (NA)-naïve patients with chronic hepatitis B (CHB). The criteria for inclusion were being NA naïve or having previous LAM-F and receiving TDF therapy for at least 6 months. Biochemical and virological tests were performed at the baseline, at 3-month intervals in the first year, and every 6 months thereafter. The primary outcome measure for efficacy was a complete virological response (CVR), defined as an HBV DNA level of <20 IU/ml. CVR rates were calculated by Kaplan-Meier analysis, and a multivariate Cox proportional-hazard model was generated in order to find predictive factors independently associated with the time to a CVR. We included 197 patients in the study (136 males; mean age, 43 ± 12 years; 105 patients were NA naïve). Sixty-five patients had hepatitis B e antigen (HBeAg)-positive CHB. The median duration of TDF treatment was 29 (range, 6 to 52) months. Seventy-one patients (77%) in the LAM-F group were treated with TDF add-on therapy. The CVR rates of the NA-naïve and LAM-F groups were comparable in HBeAg-negative (94% versus 96% at month 36, P = 0.10) and HBeAg-positive patients (67% versus 83% at month 36, P = 0.48). According to the multivariate Cox regression model, only HBeAg positivity (hazard ratio [HR], 0.39; 95% confidence interval [CI], 0.26 to 0.59; P < 0.001) and a high baseline HBV DNA level (HR, 0.44; 95% CI, 0.29 to 0.67; P < 0.001) had a significant influence on the time to a CVR. The similar cumulative CVR rates during the follow-up show that TDF has comparable efficacy in lamivudine-experienced and NA-naïve patients, and the presence of resistance mutations did not alter the response rates.

The distribution of hepatitis B virus genotypes in Thailand

Phylogenetic analysis was performed on hepatitis B virus (HBV) strains obtained from 86 hepatitis B surface antigen (HBsAg) positive donors from Thailand originating throughout the country. Based on the S gene, 87.5% of strains were of genotype C while 10.5% were of genotype B, with all genotype B strains obtained from patients originating from the central or the south Thailand. No genotype B strains were found in the north of Thailand. Surprisingly, one patient was infected with a genotype H strain while another patient was infected with a genotype G strain. Complete genome sequencing and recombination analysis identified the latter as being a genotype G and C2 recombinant with the breakpoint around nucleotide position 700. The origin of the genotype G fragment was not identifiable while the genotype C2 fragment most likely came from strains circulating in Laos or Malaysia. The performance of different HBsAg diagnostic kits and HBV nucleic acid amplification technology (NAT) was evaluated. The genotype H and G/C2 recombination did not interfere with HBV detection.

Close monitoring of hepatitis B surface antigen levels helps classify flares during peginterferon therapy and predicts treatment response

Background. Alanine aminotransferase (ALT) flares occur frequently during peginterferon (PEG-IFN) therapy. We related occurrence of flares to presence of precore (PC) and/or basal core promoter (BCP) mutants and studied kinetics of hepatitis B e antigen (HBeAg) and hepatitis B surface antigen (HBsAg) levels during flares.

Methods. Fifty of 214 (23%) patients treated with PEG-IFN ± lamivudine for 52 weeks experienced flares. Flares were host-induced (ALT elevation followed by HBV DNA decline, n = 19), virus-induced (HBV DNA increase with subsequent ALT elevation, n = 17) or indeterminate (n = 14). Presence of wild-type (WT) or non-WT (detectable PC/BCP mutants) was studied by lineprobe assay.

Results. Fifty-eight percent of host-induced flares occurred in WT HBV patients, whereas 94% of virus-induced flares occurred in patients with PC and/or BCP mutants (P = .003). HBsAg loss was only achieved in patients with a host-induced flare, and WT patients with a host-induced flare cleared HBsAg in 64% of cases. Serum HBsAg levels declined after a host-induced flare, whereas virus-induced flares were accompanied by stable or increasing levels of HBsAg. Patients with a host-induced flare achieved a mean HBsAg reduction of 3.24 log IU/mL, compared with 0.25 log IU/mL in virus-induced flares (P < .001). Patients who achieved a decline in HBsAg of >0.5 log IU/mL within 4 weeks after the flare cleared HBsAg in 64% (7 of 11) of cases.

Conclusions. Host-induced flares are associated with WT virus and may result in decline and clearance of HBV DNA, HBeAg, and HBsAg. Monitoring of HBsAg levels during and after flares may help predict a favorable treatment outcome.

Presence of precore and core promoter mutants limits the probability of response to peginterferon in hepatitis B e antigen-positive chronic hepatitis B

Peginterferon (PEG-IFN) treatment of hepatitis B e antigen (HBeAg)-positive chronic hepatitis B (CHB) results in HBeAg loss in 30% of patients, but clearance of hepatitis B virus (HBV) DNA and hepatitis B surface antigen (HBsAg) from serum is less often achieved. We investigated whether the presence of precore (PC) and basal core promoter (BCP) mutants before PEG-IFN treatment affects serological and virological response. A total of 214 HBeAg-positive CHB patients treated with PEG-IFN ± lamivudine for 52 weeks in a global randomized trial were classified at baseline as wildtype (WT) or non-WT (detectable mutants at PC/BCP) by line-probe assay. Response was assessed at 6 months posttreatment and through long-term follow-up (LTFU). Mutants were detected in 64% of patients, in varying frequencies across HBV genotypes A through D. Patients with WT had higher baseline HBV DNA, HBeAg, and HBsAg levels than patients with non-WT. Patients with WT were more likely to achieve HBeAg loss with HBV DNA <10,000 copies/mL (response, 34 versus 11%, P < 0.001) and HBsAg clearance (18 versus 2%, P < 0.001) at week 78 than non-WT patients. Among WT patients who achieved HBeAg clearance at week 78, 78% had undetectable HBV DNA and 61% achieved HBsAg clearance at LTFU (versus 26% and 15% in non-WT patients, P < 0.001 for both). The presence of WT virus at baseline was an independent predictor of response (odds ratio [OR] 2.90, 95% confidence interval [CI]: 1.15-7.31, P = 0.023) and HBsAg clearance (OR 5.58, 95% CI: 1.26-24.63, P = 0.013) and patients with non-A genotypes with detectable mutants had a low probability of response.

CONCLUSION

The presence of only WT virus at baseline is a strong predictor of response (HBeAg loss with HBV DNA <10,000 copies/mL) to PEG-IFN for HBeAg-positive CHB. Patients with detectable PC and/or BCP mutants have a lower probability of response and are less optimal candidates for PEG-IFN therapy.

Polymorphisms near IL28B and serologic response to peginterferon in HBeAg-positive patients with chronic hepatitis B

BACKGROUND & AIMS

A limited number of patients with hepatitis B e antigen (HBeAg)-positive chronic hepatitis B respond to treatment with peginterferon alfa (PEG-IFN). We investigated whether IL28B genotypes are associated with response.

METHODS

We studied 205 HBeAg-positive patients who were treated with PEG-IFN (some were also treated with lamivudine) at 11 European and Asian hospitals; genotype analysis was performed for IL28B rs12980275 and rs12979860. Response was defined as HBeAg loss with the appearance of antibodies to hepatitis B e antigen (anti-HBe) at the end of PEG-IFN therapy (HBeAg seroconversion), along with HBeAg seroconversion and hepatitis B surface antigen clearance during long-term follow-up.

RESULTS

The patients were infected with hepatitis B virus (HBV) genotypes A (13%), B (20%), C (47%), and D (13%). The proportions of IL28B genotypes were 77%, 19%, and 5% for AA/AG/GG at rs12980275 and also for CC/CT/TT at rs12979860, respectively. IL28B genotype was significantly associated with HBeAg seroconversion at the end of treatment (P < .001); the adjusted odds ratio for seroconversion was 3.16 (95% confidence interval [CI], 1.26-8.52; P = .013) for AA versus AG/GG at rs12980275 after adjustment for HBV genotype, age, levels of HBV DNA and alanine aminotransferase, and combination therapy. IL28B genotype was independently associated with an increased probability of HBeAg seroconversion during long-term follow-up (adjusted hazard ratio [HR], 2.14; 95% CI, 1.14-4.31; P = .018 for AA vs AG/GG by Cox regression analysis). Similar results were obtained for rs12979860. IL28B genotype was also associated with hepatitis B surface antigen clearance (HR, 3.47 for AA vs AG/GG; 95% CI, 1.04-13.48; P = .042).

CONCLUSIONS

Polymorphisms near IL28B are independently associated with serologic response to PEG-IFN in patients with HBeAg-positive chronic hepatitis B.

Quick genotyping detection of HBV by giant magnetoresistive biochip combined with PCR and line probe assay

Genotyping of human hepatitis B virus (HBV) can be used to direct clinically effective therapeutic drug-selection. Herein we report that a quick genotyping method for human HBV was established by a specially designed giant magnetoresistive (GMR) biochip combined with magnetic nanoclusters (MNCs), PCR and line probe assay. Magnetic nanoclusters of around 180 nm in diameter were prepared and modified with streptavidin, and resultant streptavidin-modified magnetic nanoclusters were used for capturing biotin-labeled hybrid products on the detection interface of the sensor. The gene fragments of HBV's B and C gene types were obtained by PCR based on a template of B- and C-type plasmids. After gene fragments were hybridized with captured probes, streptavidin-modified magnetic nanoclusters could bind with biotin-conjugated gene fragments, and the resultant hydride products could be quickly detected and distinguished by the GMR sensor, with a detection sensitivity of 200 IU mL(-1) target HBV DNA molecules. The novel method has great potential application in clinical HBV genotyping diagnosis, and can be easily extended to other biomedical applications based on molecular recognition.

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

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

Seasonal variation in TP53 R249S-mutated serum DNA with aflatoxin exposure and hepatitis B virus infection

BACKGROUND

Chronic hepatitis B virus (HBV) infection and dietary aflatoxin B1 (AFB1) exposure are etiological factors for hepatocellular carcinoma (HCC) in countries with hot, humid climates. HCC often harbors a TP53 (tumor protein p53) mutation at codon 249 (R249S). In chronic carriers, 1762T/1764A mutations in the HBV X gene are associated with increased HCC risk. Both mutations have been detected in circulating cell-free DNA (CFDNA) from asymptomatic HBV carriers.

OBJECTIVE

We evaluated seasonal variation in R249S and HBV in relation to AFB1 exposure.

METHODS

R249S was quantitated by mass spectrometry in CFDNA in a cross-sectional survey of 473 asymptomatic subjects (237 HBV carriers and 236 noncarriers) recruited in three villages in the Gambia over a 10-month period. 1762T/1764A HBV mutations were detected by quantitative polymerase chain reaction. In addition, the HBV S gene was sequenced in 99 subjects positive for HBV surface antigen (HBsAg).

RESULTS

We observed a seasonal variation of serum R249S levels. Positivity for R249S and average concentration were significantly higher in HBsAg-positive subjects surveyed during April-July (61%; 5,690 ± 11,300 R249S copies/mL serum) than in those surveyed October-March [32% and 480 ± 1,030 copies/mL serum (odds ratio = 3.59; 95% confidence interval: 2.05, 6.30; p < 0.001)]. Positivity for HBV e antigen (HBeAg) (a marker of HBV replication) and viral DNA load also varied seasonally, with 15-30% of subjects surveyed between April and June HBeAg positive, compared with < 10% surveyed during other months. We detected 1762T/1764A mutations in 8% of carriers, half of whom were positive for R249S. We found HBV genotype E in 95 of 99 HBsAg-positive subjects.

CONCLUSION

R249S is detectable in CFDNA of asymptomatic subjects. Evidence of temporal and quantitative variations suggests an interaction among AFB1 exposure, HBV positivity, and replication on TP53 mutation formation or persistence.

Virologic and clinical characteristics of HBV genotypes/subgenotypes in 487 Chinese pediatric patients with CHB

Background

The association of hepatitis B virus (HBV) genotypes/subgenotypes with clinical characteristics is increasingly recognized. However, the virologic and clinical features of HBV genotypes/subgenotypes in pediatric patients remain largely unknown.

Methods

Four hundred and eighty-seven pediatric inpatients with CHB were investigated, including 217 nucleos(t)ide analog-experienced patients. HBV genotypes/subgenotypes and reverse transcriptase (RT) mutations were determined by direct sequencing. The stage of fibrosis and degree of inflammatory activity were evaluated by the Metavir score system.

Results

Among 487 enrolled pediatric patients, HBV genotype C2 and B2 were the most two prevalent (73.7% and 21.1%). Comparing with HBV/B2 infected patients, no significant difference was observed in the incidence rate and mutant patterns of lamivudine- or adefovir-resistant mutations in HBV/C2 infected patients (P > 0.05). Importantly, we found that the degree of hepatic inflammation degree, fibrosis stage and ALT level were significantly higher in HBV/C2-infected HBeAg positive patients than it was in HBV/B2-infected ones.

Conclusions

The pediatric patients with HBV/C2 infection might be more susceptible to develop severe liver pathogenesis.

Evaluation of intra-host variants of the entire hepatitis B virus genome

Genetic analysis of hepatitis B virus (HBV) frequently involves study of intra-host variants, identification of which is commonly achieved using short regions of the HBV genome. However, the use of short sequences significantly limits evaluation of genetic relatedness among HBV strains. Although analysis of HBV complete genomes using genetic cloning has been developed, its application is highly labor intensive and practiced only infrequently. We describe here a novel approach to whole genome (WG) HBV quasispecies analysis based on end-point, limiting-dilution real-time PCR (EPLD-PCR) for amplification of single HBV genome variants, and their subsequent sequencing. EPLD-PCR was used to analyze WG quasispecies from serum samples of patients (n = 38) infected with HBV genotypes A, B, C, D, E and G. Phylogenetic analysis of the EPLD-isolated HBV-WG quasispecies showed the presence of mixed genotypes, recombinant variants and sub-populations of the virus. A critical observation was that HBV-WG consensus sequences obtained by direct sequencing of PCR fragments without EPLD are genetically close, but not always identical to the major HBV variants in the intra-host population, thus indicating that consensus sequences should be judiciously used in genetic analysis. Sequence-based studies of HBV WG quasispecies should afford a more accurate assessment of HBV evolution in various clinical and epidemiological settings.

Mutations in TP53 and CTNNB1 in Relation to Hepatitis B and C Infections in Hepatocellular Carcinomas from Thailand

Hepatocellular carcinoma (HCC) may develop according to two major pathways, one involving HBV infection and TP53 mutation and the other characterized by HCV infection and CTNNB1 mutation. We have investigated HBV/HCV infections and TP53/CTNNB1 mutations in 26 HCC patients from Thailand. HBV DNA (genotype B or C) was detected in 19 (73%) of the cases, including 5 occult infections and 3 coinfections with HCV. TP53 and CTNNB1 mutations were not mutually exclusive, and most of TP53 mutations were R249S, suggesting a significant impact of aflatoxin-induced mutagenesis in HCC development.

Development and validation of a hepatitis B virus DNA sequencing assay for assessment of antiviral resistance, viral genotype and surface antigen mutation status

The objective of this study was to develop a DNA sequencing assay that examines sensitively and reliably all conserved domains of the reverse transcriptase-encoding region of the HBV genome for antiviral resistance-associated mutations while simultaneously producing ample information for precise genotyping and determination of HBsAg mutation. This assay was used to examine 1000 de-identified HBV DNA positive samples with known viral loads from a broad-based, unselected patient population from across the United States. Of these, 946 were assayed successfully. Antiviral resistance-associated mutations were identified in 104 samples. The escape mutation sG145R in the surface antigen was identified in 0.8% of patient samples. Infections with genotypes A, B, C, D, E, F, G and H were observed in 36.6%, 19.6%, 21.7%, 13.5%, 3.6%, 0.7%, 2.2%, and 0.5% of patient samples respectively. Fifteen samples (1.6%) appeared to harbor infections with multiple genotypes as shown by the presence of double peaks throughout sequence electropherograms. The limit of detection of this assay was approximately 150IU/mL.

Molecular methods in the diagnosis and management of chronic hepatitis B

Chronic hepatitis B (CHB) infection remains a major global problem but the recent advances in molecular methods have revolutionized the diagnosis and management of CHB. Hepatitis B virus (HBV) DNA quantitation is the most useful molecular marker for the diagnosis and management of CHB. There is increasing evidence that the clinical outcome and efficacy of antiviral therapy for CHB could vary with the infecting HBV genotype, core promoter and precore mutations. Early identification of drug resistance is imperative in the management of CHB. The molecular methods for HBV DNA quantitation, HBV genotyping, the identification of mutants, genotypic and phenotypic methods for monitoring drug resistance and their utility and limitations for use in the diagnosis and monitoring of CHB are discussed in this article.

A study of genotypes, mutants and nucleotide sequence of hepatitis B virus in Pakistan: HBV genotypes in pakistan

BACKGROUND

Hepatitis B virus (HBV) genotypes and mutations are gaining importance in determining the clinical course of chronic liver disease.

OBJECTIVES

To determine and compare the distribution of HBV genotypes and genomic variations in Pakistan to other parts of the world.

PATIENTS AND METHODS

We conducted a prospective study at Aga Khan University Hospital from December 2006 to December 2008. HBV genotype was determined in 257 HBV DNA-positive patients. Patients were divided into two groups according to HBeAg positivity. Mutations in the pre-core and core promoter regions of HBV were determined in HBeAg-negative patients by line probe INNOLIPA assay.

RESULTS

The mean±SD age of patients was 28±5 years; there were 201 (78%) men. HBeAg was positive in 219 (85%) patients and negative in 38 (15%). HBeAg-positive patients were younger than HBeAg-negative patients (95% vs 21% in ≤30 years, p<0.001). HBV genotype D found in 247 (96.2 %) patients followed by a combined infection with HBV genotype B+D in 9 (3.3%) and 1 (0.5%) with genotype A. The mutations identified in 38 HBeAg-negative patients were T1762/A1764 in 21 (55.2%), PC mutant in 7 (18.4%), T1762/A1764/PC mutant in 2 (5%) and T1762/A1764/PC wild mutation in 1 (2%); no mutation identified in 7 (18.4%). Phylogenetic analysis did not show any significant differences between HBV genotype D isolated from Pakistan and those isolated from other parts of the world.

CONCLUSIONS

HBV genotype D is predominant in Pakistan, irrespective of HBeAg status. PC and BCP mutations were found in significant numbers of patients infected with genotype D. The HBV genotype D isolates from Pakistan are identical to the sequences isolated from other parts of the world.

INNO-LiPA HBV genotyping is highly consistent with direct sequencing and sensitive in detecting B/C mixed genotype infection in Chinese chronic hepatitis B patients and asymptomatic HBV carriers

BACKGROUND

Different HBV genotypes have effect on the progression and outcome of chronic hepatitis B (CHB) and on the response to antiviral therapy. Accurate and sensitive genotyping methods are needed in clinical practice.

METHODS

In this multicenter retrospective study, 504 HBV DNA positive serum or plasma samples of CHB patients or asymptomatic carriers were genotyped by INNO-LiPA HBV genotyping and direct sequencing. A part of the consistent and discrepant results were confirmed by clonal sequencing.

RESULTS

Except two samples with indeterminate results by INNO-LiPA, 463 had the same genotype results by INNO-LiPA and direct sequencing with a concordance of 92.23% (463/502). However 24 had completely inconsistent results by the two methods, seven of which were confirmed by clonal sequencing as the same genotype as by direct sequencing. Fifteen samples were determined as B/C mixed genotypes by INNO-LiPA but singe B or C genotype by direct sequencing, five of which were confirmed by clonal sequencing as B/C mixed infection. Further studies showed INNO-LiPA could detect 6% of genotype B and genotype C among mixed genotype samples at HBV DNA ≥3×10(3) IU/ml.

CONCLUSIONS

INNO-LiPA is accurate and sensitive in detecting B, C, D and B/C mixed genotype infection in Chinese CHB patients and asymptomatic carriers.

Prevalence of hepatitis B virus DNA polymerase mutations in treatment-naïve patients with chronic hepatitis B

BACKGROUND

One of the most important factors in treatment failure using nucleos(t)ide analogues in chronic hepatitis B is anti-viral resistance. Primary drug resistance refers to amino acid changes in the hepatitis B virus polymerase/reverse transcriptase (rt) that result in reduced susceptibility to anti-viral agents. Pre-existing drug resistance mutations may occur in untreated patients and may affect their treatment outcomes.

AIM

To determine the prevalence of hepatitis B DNA polymerase mutations in treatment-naïve patients.

METHODS

We used a direct PCR sequencing test to detect DNA polymerase mutations in 472 consecutive treatment-naïve patients at two community gastroenterology clinics in Northern California.

RESULTS

A majority of patients were Asians (>95%), had either genotype B or C (95%) and had no evidence of cirrhosis or liver cancer (94%). Mean age was 45 +/- 13 and mean hepatitis B virus DNA was 5.3 +/- 1.8 log(10) IU/mL. Most patients did not have any detectable mutations (82.4%). Some (16.7%) had mutations of unknown clinical significance (rtV207M/L/I) and only 4 patients had rtA181A/S, rtA194S or M250I.

CONCLUSIONS

No rtM204V/I or rtN236T mutations were observed in our study. Less than 1% of our patients had mutations that can be associated with primary resistance to existing anti-viral therapies for hepatitis B virus.

Quantitative detection of the M204V hepatitis B virus minor variants by amplification refractory mutation system real-time PCR combined with molecular beacon technology

Mutations in the highly conserved tyrosine-methionine-aspartate-aspartate (YMDD) motif are frequently associated with resistance to antivirals and represent a major concern in the treatment of hepatitis B virus (HBV) infection. Conventional methods fail to detect minority populations of drug-resistant viral quasispecies if they represent less than 25% of the total sample virus population. The amplification refractory mutation system real-time PCR (ARMS RT-PCR) was combined with molecular beacon technology using the LightCycler system. The samples from HBV patients selected for assay evaluation included (i) 57 samples from treatment-naïve patients for biological discriminatory ability (cutoff) estimation, (ii) 12 samples from patients with treatment failure that were M204V positive by sequencing, and (iii) 13 samples from patients with treatment failure that were negative for mutation at codon 204 by sequencing. The discriminatory ability of the assay was 0.25% when tested with laboratory-synthesized DNA target sequences. The median mutant-to-wild-type ratio for samples from naive patients tested positive for the wild type and for mutant variants was 0.01% (5th and 95th percentiles = 0.0001 and 0.04%, respectively). A value of 0.04% was selected as the biological cutoff of the assay of clinical samples. In all samples M204V positive by sequencing (12/12), the mutant variant was detected as the predominant population (range, 82.76 to 99.43%). Interestingly, in 5 (38%) of 13 samples negative by sequencing, the M204V variant was detected at a ratio above the biological cutoff (0.05 to 28%). The assay represents an efficient technique for the early detection and quantification of M204V variants before mutant strains emerge to dominate the population.

Use of the novel INNO-LiPA line probe assay for detection of hepatitis B virus variants that confer resistance to entecavir therapy

A line probe assay (INNO-LiPA DR, version 3) for the detection of hepatitis B virus mutations that confer resistance to entecavir therapy was evaluated. The INNO-LiPA DR assay is a highly sensitive assay that is easily applicable for the detection and monitoring of entecavir resistance-conferring mutations and is more sensitive than sequencing for the detection of mixed sequences.

The role of HBV genotype, core promoter and precore mutations in advanced liver disease in renal transplant recipients

BACKGROUND/AIMS

In renal transplant recipients (RTRs), chronic hepatitis B virus (HBV) infection may lead to poor outcomes. This study aimed to investigate the role of the HBV genotype, core promoter and precore mutations in advanced liver disease in RTRs.

METHODS

We retrospectively reviewed 51 RTRs positive for hepatitis B surface antigen (HBsAg). HBV genotype determination and direct sequencing of core promoter and precore regions were performed using the baseline and end-of-follow-up sera post-renal transplantation.

RESULTS

Alanine Transaminase (ALT) and HBV DNA levels were elevated after transplantation (66%). HBV genotypes B and C were found in 45 (88%) and 6 (12%) patients, respectively. There was no significant association of cirrhosis development with ALT, and hepatitis B-e antigen (HBeAg) levels, type of immunosuppressant, HBV genotype, T1762/A1764 and A1896 mutations, and duration of follow-up, except endpoint HBV DNA levels (> or =10(5)copies/ml). High T1762/A1764 mutation rates were associated with high HBV DNA levels (P=0.036) at the endpoint.

CONCLUSIONS

HBV DNA replication was enhanced in RTRs with T1762/A1764 mutation. Increased serum HBV DNA levels were associated with cirrhosis development. T1762/A1764 mutation and cirrhosis development did not show significant correlation because of small sample size and/or interventional anti-viral therapies during follow-up.

A treatment algorithm for the management of chronic hepatitis B virus infection in the United States: 2008 update

Chronic HBV infection is an important public health problem worldwide and in the United States. A treatment algorithm for the management of this disease, published previously by a panel of U.S. hepatologists, has been revised on the basis of new developments in the understanding of the disorder, the availability of more sensitive molecular diagnostic tests, and the licensure of new therapies. In addition, a better understanding of the advantages and disadvantages of new treatments has led to the development of strategies for reducing the rate of resistance associated with oral agents and optimizing treatment outcomes. This updated algorithm was based primarily on available evidence by using a systematic review of the literature. Where data were lacking, the panel relied on clinical experience and consensus expert opinion. The primary aim of antiviral therapy is durable suppression of serum HBV DNA to low or undetectable levels. Assays can now detect serum HBV DNA at levels as low as 10 IU/mL and should be used to establish a baseline level, monitor response to antiviral therapy, and survey for the development of drug resistance. Interferon alfa-2b, lamivudine, adefovir, entecavir, peginterferon alfa-2a, telbivudine, and tenofovir are approved as initial therapy for chronic hepatitis B and have certain advantages and disadvantages. Although all of these agents can be used in selected patients, the preferred first-line treatment choices are entecavir, peginterferon alfa-2a, and tenofovir. Issues for consideration for therapy include efficacy, safety, rate of resistance, method of administration, and cost.

Diagnosis and management of chronic viral hepatitis: antigens, antibodies and viral genomes

Virological tools, including serological and molecular tools, are needed to diagnose chronic hepatitis B and C infections. They may also be useful to establish their prognosis, but they have found their principal application in guiding treatment decisions and assessing the virological responses to therapy. The goal of chronic hepatitis B therapy is to prevent progression of liver disease. This is achieved if HBV replication is durably abolished or significantly reduced. In HBeAg-positive patients, HBeAg clearance followed by the HBe seroconversion phase can be achieved. In HBeAg-negative patients, long-term antiviral suppression of viral replication is needed. The loss of HBsAg, eventually associated with an HBs seroconversion, is the most desirable endpoint of therapy but is rarely achieved. The efficacy endpoint of chronic hepatitis C treatment is the sustained virological response, defined by an undetectable HCV RNA in serum with a sensitive assay 24 weeks after the end of treatment. The HCV genotype and on-treatment viral kinetics can be used to tailor treatment dosages and duration.

[Virologic techniques for the diagnosis and monitoring of hepatitis B]

Both serologic and molecular tools are useful for the diagnosis, monitoring and therapeutic management of viral hepatitis associated with hepatitis B virus (HBV). Compared with the standard tests to detect viral antigens and the antibodies directed against them, real-time PCR techniques today make it possible to quantify viral DNA more sensitively and more precisely. They thus replace the techniques previously used in most virology laboratories. New markers, such as the HBV genotype or the amino-acid substitution profile associated with HBV resistance to nucleoside and nucleotide analogs (NRTIs), can also be characterized by techniques based on sequencing or reverse hybridization. There is not currently any consensus about the first-line treatment for chronic HBV infection. Patients with a wild-type virus (HBe antigen-positive), a moderate viral load, and elevated serum alanine aminotransferase (from 2 to 5 times the upper limit of normal) are good candidates for treatment with pegylated interferon-alpha. Patients who are HBe antigen-positive and do not respond to this first-line treatment, as well as patients with chronic e-antigen-negative hepatitis B, are candidates for prolonged treatment, probably lifelong, by nucleoside or nucleotide analogs. Whatever the HBe serologic status and treatment, the efficacy of antiviral treatment is assessed by repeated measurements of viral load and serum alanine aminotransferase levels, in principle, every 12-24 months. In patients who are HBe antigen-positive, the efficacy of antiviral treatment is shown by the loss of HBe antigen, followed by the appearance of anti-HBe antibodies (HBe seroconversion), a reduction in viral load below 2x10(4)IU/mL and normalization of serum aminotransferase. In patients who are HBe antigen-negative or HBe antigen-positive but do not seroconvert after short-term treatment and who receive nucleoside or nucleotide analogs, the treatment objective is for HBV DNA to become undetectable by real-time PCR. Nonetheless, this objective is not always met, and it is recommended that viral replication be maintained at the lowest possible level for the longest possible time (ideally, lifelong). In all cases, when a virologic response to treatment is observed (significant reduction in viral load) and is followed by a relapse characterized by a viral load augmentation of at least 1 Log(10)IU/mL relative to the nadir, viral resistance to treatment must be suspected, after treatment adherence has been verified.

Impact of the hepatitis B virus genotype on pre- and post-liver transplantation outcomes

Emerging data suggest that the hepatitis B virus (HBV) genotype and the precore and core promoter variants impact the outcome of orthotopic liver transplantation (OLT) for hepatitis B. The aim of this study was to determine if there is a correlation between HBV genotype, precore and core promoter variants, and pre- and post-OLT outcomes. Serum samples from patients participating in the National Institutes of Health HBV-OLT study were tested for HBV genotype and precore and core promoter variants. A total of 123 patients were studied: 43% were Asians, 46% were Caucasians, and 8% were African Americans. HBV genotypes A (35%) and C (35%) were the most prevalent, followed by genotypes D and B. Precore and core promoter variants were detectable in 44% and 90% of patients. Patients with genotype C were more likely to have hepatocellular carcinoma (HCC) at listing (P < 0.001). Waitlist mortality was highest among patients with genotype D, while posttransplant mortality was highest among patients with genotype C. Precore or core promoter variants did not correlate with pre- or post-OLT survival. In conclusion, in this US patient population, patients with genotype C were more likely to have HCC at the time of transplant listing and to die after transplant than patients with non-C genotypes. Patients with genotype D had the highest posttransplant survival, but this was offset by higher waitlist mortality. Our study suggests that HBV genotypes but not precore or core promoter variants may have an impact on pre- and post-OLT outcomes of hepatitis B patients.

Characteristics of hepatitis B virus genotype G coinfected with genotype H in chimeric mice carrying human hepatocytes

Accumulated evidence indicated that hepatitis B virus genotype G (HBV/G) is present exclusively in coinfection with other HBV genotypes. In Mexico, HBV/G from 6 men who had sex with men were coinfected with HBV/H. Phylogenetically complete genomes of the 6 Mexican HBV/G strains were closely related to previous ones from the US/Europe. Using uPA/SCID mice with human hepatocytes, monoinfection with HBV/G did not result in detectable HBV DNA in serum, whereas superinfection with HBV/G at week 10 inoculated HBV/H when HBV/H DNA was elevated to >10(7) copies/mL has enhanced the replication of HBV/G. The HBV/G was enhanced in another 3 inoculated with a serum passage containing HBV/G with a trace of HBV/H. Coinfection of mice with HBV/G and H induced fibrosis in the liver. In conclusion, the replication of HBV/G can be enhanced remarkably when it is coinfected with HBV/H. Coinfection with HBV/G may be directly cytopathic in immunosuppressive conditions.

A Systematic Review of T-cell Epitopes in Hepatitis B Virus: Identification, Genotypic Variation and Relevance to Antiviral Therapeutics

Background

The immune response to hepatitis B virus (HBV) is important for both viral control and disease pathogenesis. A detailed understanding of the HBV-specific T-cell responses may potentially lead to novel therapeutic strategies for HBV.

Methods

All English language journal articles (including articles in press) up to October 2007 were retrieved using searches of MEDLINE, EMBASE and the Cochrane Controlled Trial Registry. An extensive database of HBV sequences (SeqHepB) and GenBank were used to assess the degree of sequence variation in each epitope. The new standardized nomenclature for HBV amino acid position number was applied to all previously defined epitopes.

Results

Forty-four HBV-specific human leukocyte antigen (HLA) class I restricted and 32 HBV-specific HLA class II restricted epitopes have been defined and have been identified in all HBV genes. The majority of HLA class I restricted epitopes have been defined in HLA-A2-positive individuals in the setting of acute HBV infection. There is significant sequence variation of these epitopes within and between HBV genotypes. Newer HBV immunotherapeutics appear promising but are still in early phases of development.

Conclusions

Identification of HBV-specific epitopes in non-HLA-A2-positive individuals and recognition of genotypic variation across epitopes are important for the future development of novel immunotherapeutic strategies for the management of chronic HBV infection.