Effect of lamivudine therapy on the serum covalently closed-circular (ccc) DNA of chronic hepatitis B infection

Role of hepatitis B virus in development of hepatocellular carcinoma: Focus on covalently closed circular DNA

Chronic infection with hepatitis B virus (HBV) remains a major global health problem, especially in developing countries. It may lead to prolonged liver damage, fibrosis, cirrhosis, and hepatocellular carcinoma. Persistent chronic HBV infection is related to host immune response and the stability of the covalently closed circular DNA (cccDNA) in human hepatocytes. In addition to being essential for viral transcription and replication, cccDNA is also suspected to play a role in persistent HBV infections or hepatitis relapses since cccDNA is very stable in non-dividing human hepatocytes. Understanding the pathogenicity and oncogenicity of HBV components would be essential in the development of new diagnostic tools and treatment strategies. This review summarizes the role and molecular mechanisms of HBV cccDNA in hepatocyte transformation and hepatocarcinogenesis and current efforts to its detection and targeting.

The Effectiveness of Antiviral Treatments for Patients with HBeAg-Positive Chronic Hepatitis B: A Bayesian Network Analysis

This network analysis is to determine the most effective treatment in HBeAg-positive patients. PubMed databases were searched for randomized controlled trials. Bayesian network meta-analysis was used to calculate the pairwise hazard ratios, 95% credible intervals, and ranking of surrogate outcomes. 9 studies were identified. The results show that NA add-on PEG IFN might be a better antiviral approach for HBeAg-positive patients in end point of treatment, with a comparable results of nucleoside/nucleotide analogs (NA), PEG IFN, PEG IFN add-on NA, PEG IFN combined NA, and PEG IFN combined placebo in alanine aminotransferase (ALT) normalization and HBV DNA undetectable. Cumulative probabilities of being the most efficacious treatment were NA add-on PEG IFN (30%) for HBeAg loss. The second efficacious (23%) is HBeAg seroconversion. This network analysis shows that NA add-on PEG IFN might be a better antiviral approach for HBeAg-positive patients in end point of treatment. But the long-term efficiency should be further determined.

A Highly Sensitive and Robust Method for Hepatitis B Virus Covalently Closed Circular DNA Detection in Single Cells and Serum

Despite implications of persistence of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) in the development of hepatocellular carcinoma (HCC), little is known about serum cccDNA in HBV-infected diseases. We developed a cccDNA-selective droplet digital PCR (ddPCR) to assess cccDNA content and dynamics across different stages of HCC development. One hundred forty-seven serum samples and 35 formalin-fixed, paraffin-embedded tumor tissues were derived from patients with HCC or HBV hepatitis/cirrhosis. After specific amplification and selective digestion, probe-based ddPCR was used to quantify cccDNA copy numbers in single cells and clinical samples. The cccDNA in single HepG2.2.15 cells ranged from 0 to 10.8 copies/cell. Compared with non-HCC patients, HCC patients showed a higher cccDNA-positive rate (89.9% versus 53.2%; P = 4.22 × 10^-6) and increased serum cccDNA contents (P = 0.002 and P = 0.041 for hepatitis and cirrhosis patients, respectively). Serum cccDNA ranged from 84 to 1.07 × 10⁵ copies/mL. Quantification of serum cccDNA and HBV-DNA was an effective way to discriminate HCC patients from non-HCC patients, with areas under the curve of receiver operating characteristic of 0.847 (95% CI, 0.759-0.935; sensitivity, 74.5%; specificity, 93.7%). cccDNA-selective ddPCR is sensitive to detect cccDNA in single cells and different clinical samples. Combined analysis of serum cccDNA and HBV-DNA may be a promising strategy for HBV-induced HCC surveillance and antiviral therapy evaluation.

Detection of HBV Covalently Closed Circular DNA

Chronic hepatitis B virus (HBV) infection affects approximately 240 million people worldwide and remains a serious public health concern because its complete cure is impossible with current treatments. Covalently closed circular DNA (cccDNA) in the nucleus of infected cells cannot be eliminated by present therapeutics and may result in persistence and relapse. Drug development targeting cccDNA formation and maintenance is hindered by the lack of efficient cccDNA models and reliable cccDNA detection methods. Southern blotting is regarded as the gold standard for quantitative cccDNA detection, but it is complicated and not suitable for high-throughput drug screening, so more sensitive and simple methods, including polymerase chain reaction (PCR)-based methods, Invader assays, in situ hybridization and surrogates, have been developed for cccDNA detection. However, most methods are not reliable enough, and there are no unified standards for these approaches. This review will summarize available methods for cccDNA detection. It is hoped that more robust methods for cccDNA monitoring will be developed and that standard operation procedures for routine cccDNA detection in scientific research and clinical monitoring will be established.

Hepatitis B viral infection of hepatic progenitor cells. Resolving unresolved questions?

Accumulated data to date do not entirely explain the; propensity of the hepatitis B virus (HBV) to cause chronic infections in newborns; failure of antiviral agents to resolve infections or precise mechanism whereby HBV causes hepatocellular carcinoma (HCC). Based on the increased numbers of hepatic stem/progenitor cells (HPCs) present within the neonatal liver, the refractoriness of these cells to the effects of interferons and xenobiotics and their ability to undergo malignant transformation, we hypothesize that HBV infection of HPCs could explain these and perhaps other clinical features of chronic HBV.

New paradigms in hepatitis B management: only diamonds are forever

INTRODUCTION

The hepatitis B virus (HBV) causes chronic hepatitis B (CHB) in ∼350 million people worldwide who have an increased risk of end-stage liver disease and/or hepatocellular carcinoma.

SOURCES OF DATA

Several peer-reviewed papers featuring new approaches to anti-HBV management. Additionally, we also reviewed recent abstract presentations at international congresses.

AREAS OF AGREEMENT

There has been great progress in CHB therapy with the development of standard and pegylated interferon (i.e. PEG-IFN) as well as nucleos/tide analogs (NAs). IFN has both antiviral and immunomodulatory effects and through immune-mediated destruction of infected hepatocytes offers the possibility of finite therapy. However, this 'killing for a cure' antiviral strategy may not be tolerated in many, especially in cirrhotic patients. NAs inhibit viral reverse transcriptase, have few side effects and prevent liver disease progression, but cannot offer a cure as they have little effect on the resilient HBV covalently closed circular DNA (cccDNA) intermediate. Moreover, NAs such as tenofovir and entecavir offer a high genetic barrier to resistance, but are expensive and not readily available in many global regions.

GROWING POINTS

Despite significant treatment advances, there is increased recognition of the need for improved anti-HBV treatments, and new virologic tests for monitoring treatment response.

AREAS OF CONTROVERSY

The role of quantitative hepatitis B surface antigen, intrahepatic cccDNA levels and viral genotype in selecting treatment candidates and refining NA stopping rules.

AREAS TIMELY FOR DEVELOPING NEW RESEARCH

Potential new therapies include viral entry inhibitors, RNA interference technologies (i.e. RNAi) and small molecules that modulate cccDNA transcription, as well as novel immunomodulatory therapies to boost HBV-specific T cell responses. The ultimate goal of new tests and anti-HBV therapies is to reduce the burden and expense of life-long CHB treatment, as 'only diamonds are forever'.

High incidence of lamivudine-resistance-associated vaccine-escape HBV mutants among HIV-coinfected patients on prolonged antiretroviral therapy

BACKGROUND

Worldwide, frequent emergence of lamivudine (3TC)-resistant HBV mutants has been reported in HIV-HBV-coinfected patients during long-term antiretroviral therapy (ART) that contains 3TC as the sole anti-HBV drug. Three major patterns of mutations in HBV polymerase gene, namely single (rtM204V), double (rtL180M+rtM204V) and triple (rtV173L+rtL180M+rtM204V) mutations, are associated with 3TC-resistance; additionally, the triple mutation has vaccine-escape potential due to a corresponding change in overlapping surface gene. Data from India, a major reservoir for HIV and HBV infection, is lacking. Here we investigated the effect of long-term 3TC treatment on virological response for HBV and characterized the 3TC-resistant HBV mutations in a cohort of HIV-HBV-coinfected patients from eastern India.

METHODS

A cross-sectional study was performed in HIV-infected patients (n=563) receiving 3TC-containing ART for ≥6 months from the major ART centre of eastern India during 2011-2012. The hepatitis B surface antigen-positive HIV-infected patients (n=62) were categorized into four groups with comparable sample size according to the 3TC exposure for ≥6-<12 months (group I; n=15), ≥12-<24 months (group II; n=20), ≥24-<48 months (group III; n=13) and ≥48 months (group IV; n=14). Patients' plasma samples were examined for hepatitis B e antigen (HBeAg), HBV DNA, viral load and covalently closed circular DNA (cccDNA). HBV reverse transcriptase region was sequenced.

RESULTS

With a longer period of 3TC exposure, the frequency of HIV-HBV-coinfected patients having HBV DNA suppression decreased. The prevalence of HBeAg-positivity, serum HBV DNA load >2,000 IU/ml and 3TC-resistant mutations simultaneously increased. Remarkably, the 3TC-resistant triple mutation predominated over the double mutation in this cohort (32.26% versus 19.34%) and prevailed in significantly higher frequency among HBV viraemic patients experiencing 3TC for ≥48 months (60% versus 10%; P=0.03). Patients with 3TC-resistant triple mutants had HBV genotype-D, high serum HBV DNA load and elevated alanine aminotransferase level, and presence of cccDNA in their serum.

CONCLUSIONS

Considering this alarmingly high incidence of 3TC-resistant triple mutation and its possible clinical/public health implications, proper management of 3TC-resistance among HIV-HBV-coinfected patients is an urgent necessity in India.

Effects of entecavir on hepatitis B virus covalently closed circular DNA in hepatitis B e antigen-positive patients with hepatitis B

The aim of this study was to assess the effect of 48-week entecavir therapy on serum and intrahepatic hepatitis B virus, covalently closed circular DNA (HBV cccDNA) levels in hepatitis B e antigen (HBeAg)-positive patients. A total of 120 patients with HBeAg-positive chronic hepatitis were treated with entecavir for 48 weeks. Serum HBV markers, total HBV DNA, and HBV cccDNA levels were measured at baseline and week 48. Biopsies from 20 patients were available for both intrahepatic total HBV DNA and cccDNA testing at these timepoints. HBV cccDNA levels were decreased from a median level of 5.1×10⁶ copies/mL at baseline to a median level of 2.4×10³ copies/mL at week 48. Reduction magnitudes of HBV cccDNA in patients with normalized alanine aminotransferase levels and those undergoing HBeAg seroconversion were significantly greater than those in alanine aminotransferase-abnormal and HBeAg positive patients. Intrahepatic HBV cccDNA was decreased significantly after 48 weeks of treatment, but could not be eradicated. In conclusion, treatment of HBeAg-positive hepatitis B patients with entecavir for 48 weeks decreased serum and intrahepatic HBV cccDNA significantly, and the magnitude of HBV cccDNA reduction was related to total HBV DNA decrease, alanine aminotransferase normalization, and HBeAg seroconversion.

Development of magnetic capture hybridization and quantitative polymerase chain reaction for hepatitis B virus covalently closed circular DNA

BACKGROUND

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) served as a vital role in the life cycle of the virus and persistent infection. However, specific and quantitative methods for cccDNA detection have not been available.

OBJECTIVES

Our aim was to develop and primarily evaluate a quantitative method for HBV cccDNA based on magnetic capture hybridization and quantitative PCR technology.

MATERIALS AND METHODS

The functionalized-nanoparticles specifically to capture HBV cccDNA, located on both sides of relaxed circle DNA (rcDNA) gap, were designed. Then, magnetic capture hybridization and quantitative PCR (MCH-qPCR) assay were developed and its performance was primarily evaluated with cccDNA standards and serum samples of patients with chronic hepatitis B.

RESULTS

Specific nanoparticles of cccDNA capture were prepared and a magnetic capture hybridization and quantitative assay method for cccDNA was developed successfully. The limit of detection was 90 IU/mL, and a good linear relationship in the range of 10(2)-10(6) IU/mL was revealed (r(2) = 0.994) with the MCH-qPCR. Compared with directly real-time PCR, a high content of HBV DNA did not affect the detection of cccDNA for the MCH-qPCR method, and there was no cross-reactivity between cccDNA and rcDNA.

CONCLUSIONS

The novel MCH-qPCR method has good sensitivity and specificity. It could meet the requirement of clinical routine detection.

Levels of hepatitis B virus replicative intermediate in serum samples of chronic hepatitis B patients

Hepatitis B virus (HBV) cccDNA levels is an absolute marker of HBV replication in the liver of HBV infected patients. This study aimed to quantify the HBV cccDNA levels in sera and liver tissue samples of treatment naïve patients with chronic hepatitis B. Eighty one chronic hepatitis B (CHB) treatment naïve patients were enrolled from January 2009 to June 2011. Total HBV DNA and HBV cccDNA levels were quantified using sensitive real time PCR assay. The mean age of recruited patients was 34 ± 11.5 years. Fifty four (66.7%) patients were HBeAg negative. Liver tissue samples were available from 2 HBeAg positive and 21 HBeAg negative CHB patients. The amount of total intrahepatic HBV DNA ranged from 0.09 to 1508.92 copies/cell. The median intrahepatic HBV cccDNA was 0.31 and 0.20 copies/cell in HBeAg positive and HBeAg negative cases, respectively. Serum HBV cccDNA was detectable in 85.2 % HBeAg positive and 48.1% HBeAg negative CHB patients. Median serum HBV cccDNA was 46,000 and 26,350 copies/mL in HBeAg positive and HBeAg negative subjects, respectively. There was a significant positive correlation between the levels of intrahepatic total HBV DNA and intrahepatic HBV cccDNA (r = 0.533, p = 0.009). A positive correlation was also seen between serum HBV cccDNA levels and serum HBV DNA levels (r = 0.871, p < 0.001). It was concluded that serum HBV cccDNA could be detectable in higher proportion of HBeAg positive patients compared to HBeAg negative patients. Moreover, the median level of serum HBV cccDNA was significantly higher in HBeAg positive patients in contrast to HBeAg negative subjects.

Chronic hepatitis B treatment initiation and modification patterns in five European countries: a 2-year longitudinal, non-interventional study

BACKGROUND

Chronic hepatitis B (CHB) is an important health concern, but there are few studies describing its management in different countries. This prospective, longitudinal, non-interventional study aimed to assess differences in CHB management in five European countries (Germany, France, Poland, Romania and Turkey).

METHODS

Data were collected from CHB patients' records between 2008 and 2010. Patients were stratified by treatment status at baseline (treated or untreated). The primary objective was to estimate the probability of a CHB management modification (treatment initiation or change) among patients from each country during a 2-year follow-up.

RESULTS

A total of 1,267 patients were included (567 treated, 700 untreated). Baseline characteristics between countries and treatment status groups were broadly comparable. Most patients had an alanine aminotransferase measurement in the 12 months prior to baseline; proportions of patients with an HBV DNA assessment varied by country and treatment status. The Kaplan-Meier-estimated probability of any treatment modification ranged from 9.4% (Turkey) to 30.1% (Poland) at 12 months and 10.0% (Turkey) to 40.0% (Poland) at 24 months. Modifications were more common in treated than untreated patients. The most frequently reported reasons for modifying treatment were HBV-DNA-related. The majority of treated patients were treated with monotherapy; however, choice of therapy differed between countries.

CONCLUSIONS

This is the first longitudinal study describing CHB management in European countries. Differences were observed in treatment and monitoring between countries, but alanine aminotransferase and HBV DNA levels consistently emerged as key tests in the management of CHB in all five countries.

Role of molecular diagnostics in the management of viral hepatitis B

INTRODUCTION

Despite the availability of a safe and effective vaccine, chronic hepatitis B virus (HBV) infection continues to be a global health concern with an estimated 350 - 400 million people infected worldwide. Globally, HBV is the leading cause of chronic liver disease that may progress to cirrhosis and hepatocellular carcinoma. Therefore, accurate diagnosis and classification of the disease are important to determine whether therapy is needed.

AREAS COVERED

The review contains an overview of recent data on the existing and emerging developments in the molecular diagnostic and monitoring tools for chronic liver disease.

EXPERT OPINION

Monitoring of HBV viral load is the most widely used method in assessing liver disease severity, predicting development of cirrhosis and hepatocellular carcinoma, deciding initiation of antiviral therapy, assessing treatment response as well as early detection of emergence of drug resistance. Some recent studies have downplayed the importance of viral load in HBV management. Phenotyping/genotyping methods can establish emergent resistance to antivirals. Increasing number of reports suggest that clinical outcome and efficacy of antiviral treatment might vary with HBV genotype and precore/core promoter mutants. The importance of covalently closed circular DNA is also becoming apparent in this regard. Further studies on the development of newer molecular methods for a better management of chronic hepatitis B (CHB) will minimize morbidity in CHB.

Validation of a sensitive and specific real-time PCR for detection and quantitation of hepatitis B virus covalently closed circular DNA in plasma of chronic hepatitis B patients

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) serves as a template for viral replication and plays a role in persistence of HBV infection. The origin and significance of cccDNA in plasma, however, are not well understood. A sensitive, specific, and reproducible real-time PCR for detection and quantitation of cccDNA in plasma of chronic hepatitis B patients was developed and validated. Four HBV DNA reference panels and 96 plasma samples of chronic hepatitis B patients are analyzed. Results are compared with total HBV DNA levels. This cccDNA assay had a lower limit of detection at 15 copies/PCR, a lower limit of quantitation at 91 copies/PCR, and a correlation coefficient (R) of 0.98 (p < 0.0001). HBV cccDNA can be detected in two of four international panels. Significant correlation is found between cccDNA and total HBV DNA levels in both panels (R = 0.96 and R = 0.43) and in samples of the chronic hepatitis B patients (R = 0.88, p < 0.0001). In 57 % of these samples cccDNA can be detected. Mean level of cccDNA is 0.16 % of total HBV load. Plasma HBV cccDNA levels are higher in HBeAg-positive samples than in HBeAg-negative samples (p < 0.0001). Total HBV DNA levels and HBV genotype do not influence cccDNA detection.

Correlation between intrahepatic hepatitis B virus cccDNA levels and other activity markers in patients with HBeAg-negative chronic hepatitis B infection

OBJECTIVE

The aim of this study was to demonstrate the relation between intrahepatic (IH) hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) levels and the other HBV replicative intermediates and hepatocyte expression of HBV antigens.

PATIENTS AND METHODS

Patients with hepatitis B surface antigen (HBsAg) positivity, hepatitis B early antigen negativity, serum HBV DNA levels 10 copies/ml or more, and constantly or intermittently increased alanine aminotransferase levels were included.

RESULTS

Fifty-nine patients were included. There was a good correlation between the levels of IH HBV cccDNA and serum HBV DNA (P<0.001). Serum HBsAg levels were weakly correlated with IH HBV cccDNA levels and moderately correlated with serum HBV DNA (r=0.322, P=0.017; r=0.489, P=0.001, respectively). There were no significant correlation between serum HBsAg level and histologic activity index groups (P=0.691), but stage 0, 1, and greater than 2 fibrosis groups were positively correlated with serum HBsAg levels (P=0.019). IH cccDNA and serum HBV DNA were significantly different in hepatitis B core antigen staining groups (P=0.008 and <0.001, respectively) but there was no significant correlation between HBsAg staining groups and HBV replication markers. There was a weak correlation between serum HBsAg levels and IH HBsAg and hepatitis B core antigen levels (r=0.333, P=0.012; r=0.366, P=0.006, respectively). In multivariate analysis, alanine aminotransferase, age, fibrosis stage, and serum HBsAg quantitation were the most important factors predicting IH HBV cccDNA level.

CONCLUSION

Histopathologic damage, serum HBV DNA levels, and IH HBV replication markers have a more complex and dynamic process. However, both serum and IH HBV replication markers provide important knowledge about the activity of the disease.

Quantitation of HBV covalently closed circular DNA in micro formalin fixed paraffin-embedded liver tissue using rolling circle amplification in combination with real-time PCR

BACKGROUND

The study aimed to develop an effective method to quantitate HBV covalently closed circular DNA (cccDNA) using small section of formalin fixed paraffin-embedded (FFPE) liver biopsy.

METHODS

Plasmid-safe ATP-dependent DNase (PSAD)-treated samples were subjected to rolling circle amplification (RCA) prior to real-time PCR mediated by cccDNA-selective primers. Human beta-actin gene was used as a reference control.

RESULTS

Compared to the classical method, i.e., PSAD digestion+real-time PCR, introduction of RCA increased the lower limit of detection for about 2 logs with good inter- and intra-assay reproducibility. HBV cccDNA was detected in 91.5% (119/130) of the FFPE samples. The cccDNA levels (copy/cell) between FFPE liver tissues and fresh frozen counterpart tissues were comparable. The median of cccDNA level in HBeAg-positive patients was higher than that in HBeAg-negative ones (52.60 vs. 31.25copies/cell, P<0.01). Intrahepatic cccDNA level was positively correlated with intrahepatic HBV total DNA level, but not obviously correlated with serum HBV DNA or alanine aminotransferase levels.

CONCLUSIONS

The method could sensitively and specifically quantitate intrahepatic HBV cccDNA in micro FFPE liver biopsy tissue for evaluation of HBV replication status in the liver.

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.

Hepatitis B virology for clinicians

A basic understanding of the molecular events involved in the hepatitis B virus (HBV) life cycle is essential to better appreciate the natural history and atypical presentations of the disease and to develop individual management plans based on readily available virologic tests. With the improved knowledge gained from studying the molecular biology of HBV, novel approaches to inhibition of viral replication are being explored, such as viral entry inhibitors, nucleocapsid inhibitors, and inhibitors of viral assembly. However, the ultimate goal of therapy is to identify strategies to eliminate covalently closed circular DNA from infected hepatocytes. This article serves to introduce the clinically relevant aspects of the HBV life cycle as they pertain to patient management.

Virological response to antiviral therapy at week 12 indicates a great reduction of intrahepatic hepatitis B virus DNA and cccDNA in HBeAg-positive chronic hepatitis B patients

Early virological response is considered to be a predictor for the outcome of anti-hepatitis B virus (HBV) therapy. To analyze its correlation to intrahepatic HBV DNA and covalently closed circular DNA (ccc)DNA, 71 hepatitis B virus e antigen (HBeAg)-positive chronic hepatitis B patients were recruited: 34 patients were treated with lamivudine; 13 with interferon-alpha2b; and 24 with sequential therapy of lamivudine-interferon-alpha2b for 48 weeks. Intrahepatic HBV DNA and cccDNA load were measured at the baseline and at Week 48. Fifty-seven patients had virological response at Week 12. Median decreases of serum HBV DNA in patients with or without virological response at Week 12 were 4.0 log(10) (max. 6.2, min. 2.2) and 1.1 log(10) (max. 2.1, min. 0) (Z = -5.766, P = 0.0000), respectively. At Week 48 they were 4.1 log(10) (max. 7.4, min. 1.0) and 2.3 log(10) (max. 7.5, min. 0.3) (Z = -2.760, P = 0.006), respectively. For intrahepatic HBV DNA load they were 1.3 log(10) (max. 4.3, min. -1.2) and 0.6 log(10) (max. 3.5, min. -0.8), respectively, and for HBV cccDNA load they were 1.1 log(10) (max. 4.8, min. -0.5) and 0.5 log(10) (max. 3.0, min. -0.8) (Z = -2.097, P = 0.036), respectively at Week 48. Step-wise logistic regression analysis indicated that the baseline intrahepatic HBV DNA load effected virological response at Week 12 [odds ratio (OR) 0.405; 95% confidence interval (CI) 0.174-0.944; P = 0.036] and HBeAg seroconversion at Week 48 (OR 0.292; 95% CI 0.131-0.649; P = 0.003). In conclusion, virological response at Week 12 indicated a great reduction of intrahepatic DNA and cccDNA load in HBeAg-positive CHB patients. The baseline intrahepatic HBV DNA load affected virological response at Week 12 and HBeAg seroconversion at Week 48.

Validation of a sensitive and specific real-time PCR for detection and quantitation of hepatitis B virus covalently closed circular DNA in plasma of chronic hepatitis B patients

Hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) serves as a template for viral replication and plays a role in persistence of HBV infection. The origin and significance of cccDNA in plasma however, is not well understood. A sensitive, specific, and reproducible real-time PCR for detection and quantitation of cccDNA in plasma of chronic hepatitis B patients was developed and validated. Four HBV DNA reference panels, and 96 plasma samples of chronic hepatitis B patients were analyzed. Results were compared with total HBV DNA levels, individual ALT levels and the Histology Activity Index (HAI). This cccDNA assay had a lower limit of detection at 15 copies/PCR, a lower limit of quantitation at 91 copies/PCR and a correlation coefficient (R) of 0.98 (P < 0.0001). cccDNA was detected in two of four international panels. Significant correlation was found between cccDNA and total HBV DNA levels in both panels (R = 0.96, and R = 0.43) and in samples of the chronic hepatitis B patients (R = 0.88, P < 0.0001). In 57% of these samples cccDNA was detectable. Mean level of cccDNA was 0.16% of total HBV load. Plasma cccDNA levels were higher in HBeAg positive samples than in HBeAg negative samples (4.91 log copies/ml vs. 3.88 log copies/ml, P < 0.0001). Levels of total HBV DNA and HBV genotype did not influence cccDNA detection. ALT levels and HAI-score were not correlated with plasma cccDNA levels. These findings suggest that cccDNA levels in plasma are not the result of increased hepatocyte degeneration, but indicate that other mechanisms might be responsible.

The significance of enzyme immunoassay for the assessment of hepatitis B virus core-related antigen following liver transplantation

PURPOSE

Recently, a new enzyme immunoassay for the detection of hepatitis B virus (HBV) core-related antigen (HBcrAg) has been reported. In this study, we proposed to account for feasibility of HBcrAg assay, and discuss the dynamics of HBV seen in patients following HBV-related living donor liver transplantation (LDLT).

METHODS AND RESULTS

This study involved 12 patients; 11 patients had positive serum HBcrAg, and 6 patients had negative HBV-DNA. In the post-operation period, all cases were negative for HBV-DNA and HBsAg in sera under prophylaxis therapy. At post-operation, 5 of the 12 had positive serum HBcrAg, and at stable state, 6 had positive serum HBcrAg postoperatively. The mean levels of HBcrAg following LDLT were significantly lower than those seen in the preoperative-operation stage.

CONCLUSION

This enzyme immunoassay is a readily utilizable marker of HBV replication in the post transplantation stage. Furthermore, the evaluation of HBV activity by HBcrAg assay must be studied to determine the appropriate prophylaxis for controlling replication of HBV following LDLT.

Correlation between serum hepatitis B virus core-related antigen and intrahepatic covalently closed circular DNA in chronic hepatitis B patients

Nucleos(t)ide analogues are utilized for the treatment of chronic HBV infection, and HBe seroconversion and HBV DNA levels are commonly used as markers of viral status and as primary treatment endpoints. Recently, a new assay was prepared for the detection of serum HBV core-related antigen (HBcrAg), consisting of HBcAg, HBeAg, and p22cr, which is a precore protein from amino acid -28 to at least amino acid 150, by coding the precore/core region. In this study, we examined the correlation between serum HBcrAg concentration and viral status by the analysis of serum HBeAg, HBsAg, peripheral HBV DNA, and intrahepatic covalently closed circular DNA (cccDNA) in 57 chronic hepatitis B patients. Intrahepatic cccDNA was detected in all 57 patients, 42 patients were HBcrAg-positive, and serum HBcrAg concentration level was closely correlated with cccDNA. Additionally, positive HBcrAg concentration level results were observed in 6 out of 13 HBsAg seroclearance patients and 20 out of 31 HBV DNA-negative patients. Moreover, the correlation between HBcrAg and cccDNA in these 31 HBV DNA-negative patients was statistically significant (r = 0.482, P = 0.006). These data suggest that serum HBcrAg concentration is well correlated with intrahepatic cccDNA level, and that the measurement of serum HBcrAg may be clinically useful for monitoring intrahepatic HBV viral status, especially in patients under treatment with nucleos(t)ide analogues.

Quantification of hepatitis B virus covalently closed circular DNA in peripheral blood and hepatic tissues of cirrhotic patients with hepatitis B

AIM: To investigate the distribution of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) in peripheral blood and liver tissues of liver cirrhosis patient with hepatitis B virus infection.

METHODS: DNA was extracted from serum and liver biopsy samples of 60 cirrhotic patients with hepatitis B virus infection. The serum samples were treated with Plasmid-Safe ATP dependent Dnase (PSAD), while the liver biopsy samples were digested with restriction enzymes MluI and PSAD to reduce non-HBV cccDNA; then the total HBV DNA and cccDNA were measured by the real-time PCR assay.

RESULTS: HBV cccDNA was negative in all the serum samples, but positive in 40% (24/60) hepatic biopsy samples. In HBeAg-positive, HBeAg-negative plus HBeAb-negative, and HBeAb-positive hepatic tissues, HBV cccDNA positive rate was 66.7%, 52.9% and 26.5%, respectively. Meanwhile, the positive rate had significant difference between HBeAg-positive group and HBeAb-positive group (P < 0.05). Intrahepatic cccDNA accounted for 0%-7.77% of total HBV DNA, and there was a significant correlation between intrahepatic cccDNA and total HBV DNA (r = 0.53, P < 0.01). Intrahepatic cccDNA had no correlation with the total HBV DNA in the serum samples, as well as with ALT and TBIL levels (r = 0.15, P = 0.25; r= 0.01, P = 0.94).

CONCLUSION: HBV cccDNA can not be detected in peripheral blood of cirrhotic patients with hepatitis B virus infection. Intrahepatic cccDNA accounts for a small proportion of the total HBV DNA. Replication of HBV is the most active in HBeAg-positive patients.

New developments in HBV molecular diagnostics and quantitative serology

New standardized assays for the quantification of hepatitis B virus (HBV) DNA have yielded insights into the association of HBV DNA levels with the relative risk of developing liver disease. Quantification of HBV DNA has also played a role in the management of chronic hepatitis B by allowing criteria to be established for determining patient eligibility for antiviral therapy, monitoring response, and identifying the development of resistance. In addition to serum HBV DNA levels, the HBV genotype may influence disease progression and response to therapy. However, many of the studies that have included genotype assessment do not compare across the range of genotypes, and current management guidelines do not incorporate genotype determination. More recently, quantitative assays for intrahepatic HBV replicative intermediates, as well as hepatitis B e antigen and hepatitis B surface antigen, indicate that these factors may have promise in identifying patients likely to respond to treatment. Additional work is needed to standardize and validate these assays before they can be considered to be of true diagnostic value. A wide variety of research techniques are being used to investigate chronic hepatitis B. Further evaluation is needed to decide which will have the greatest clinical applicability.

Should chronic HBV infected patients with normal ALT treated: debate

Alanine aminotransferase (ALT) levels have traditionally been used for treatment decisions in chronic hepatitis B virus (CHBV) infected patients. But recent data have raised doubts on this wisdom, as a significant proportion of CHBV infected patients with normal ALT have high HBVDNA levels and significant liver injury at presentation especially in areas of intermediate to high endemicity. A normal ALT value only identifies patients less likely to respond to current treatments, rather than patients who are not in need of the treatment. Patients with CHBV infection with normal ALT should be considered for treatment based on the HBV DNA levels and histological injury.

Effects of antiviral agents and HBV genotypes on intrahepatic covalently closed circular DNA in HBeAg-positive chronic hepatitis B patients

AIM: To evaluate the effects of antiviral agents and HBV genotypes on intrahepatic covalently closed circular DNA (ccc DNA) in HBeAg-positive chronic hepatitis B patients.

METHODS: Seventy-one patients received lamivudine (n = 35), or sequential therapy with lamivudine- interferon alpha 2b (IFN-α 2b, n = 24) for 48 wk, or IFN-α 2b (n = 12) for 24 wk. All subjects were followed up for 24 wk. Intrahepatic ccc DNA was measured quantitatively by PCR. HBV genotypes were analyzed by PCR-RFLP.

RESULTS: Sequential lamivudine- INF-α therapy, lamivudine and INF-α monotherapy reduced ccc DNA of 1.7 log, 1.4 log and 0.8 log, respectively (P < 0.05). Seventeen out of the 71 patients developed HBeAg seroconversion, the reduction of ccc DNA in the HBeAg seroconversion patients was more significant than that in the HBeAg positive patients (3.0 log vs 1.6 log, P = 0.0407). Twenty-four weeks after antiviral therapy withdrawal, 16 patients had a sustained virological response, the baseline intrahepatic ccc DNA in the patients with a sustained virological response was significantly lower than that in the patients with virological rebound (4.6 log vs 5.4 log, P = 0.0472). HBV genotype C accounted for 85.9% (n = 61), and genotype B for 14.1% (n = 10), respectively, in the 71 patients. There was no significant difference in the change of ccc DNA level between HBV genotypes C and B (2.1 log vs 1.9 log).

CONCLUSION: Forty-eight week sequential lamivudine-INF-α therapy and lamivudine monotherapy reduce ccc DNA more significantly than 24-wk INF-α monotherapy. Low baseline intrahepatic ccc DNA level may predict the long-term efficacy of antiviral treatment. HBV genotypes C and B have no obvious influence on ccc DNA load.

Virologic monitoring of hepatitis B virus therapy in clinical trials and practice: recommendations for a standardized approach

Treatment of chronic hepatitis B virus (HBV) infection is aimed at suppressing viral replication to the lowest possible level, and thereby to halt the progression of liver disease and prevent the onset of complications. Two categories of drugs are used in HBV therapy: the interferons, including standard interferon alfa or pegylated interferon alfa, and specific nucleoside or nucleotide HBV inhibitors that target the reverse-transcriptase function of HBV-DNA polymerase. The reported results of clinical trials have used varying definitions of efficacy, failure, and resistance based on different measures of virologic responses. This article discusses HBV virologic markers and tests, and their optimal use both for planning and reporting clinical trials and in clinical practice.

Molecular testing in the diagnosis and management of chronic hepatitis B

Hepatitis B virus (HBV) is an enveloped virus with a small (3.2-kb) partially double-stranded DNA genome that causes acute and chronic infections. The impact of these infections on public health worldwide is enormous, with an estimated prevalence of 2 billion acute infections and 360 million chronic infections globally. This review focuses on chronic hepatitis B and the molecular assays used in its diagnosis and management. Background information, including that about features of the hepatitis B virion, viral replication, and epidemiology of infection, that is important for understanding chronic hepatitis B and molecular diagnostic tests for HBV is provided. To facilitate an understanding of the utility of molecular testing for chronic hepatitis B, the four stages of chronic hepatitis B infection that are currently recognized, as well as an additional entity, occult hepatitis B, that can be diagnosed only by sensitive nucleic acid amplification methods, are reviewed in detail, including available therapeutic agents. The molecular diagnostic content focuses on tests for HBV DNA quantification, genotyping, and mutation detection (including precore/core promoter and antiviral resistance mutations). The discussion of these tests encompasses their current utility and performance characteristics, drawing from current clinical guidelines and other studies from the literature. In recognition of the continual evolution of this field, the final section describes emerging molecular markers with future diagnostic potential.

Serum HBV RNA is a predictor of early emergence of the YMDD mutant in patients treated with lamivudine

Lamivudine (LAM) is a nucleoside analogue widely used for the treatment of chronic hepatitis B virus (HBV) infection. Emergence of resistant strains with amino acid substitutions in the tyrosine-methionine-aspartate-aspartate (YMDD) motif of reverse transcriptase is a serious problem in patients on LAM therapy. The amount of covalently closed circular DNA in the serum is reported to be higher in patients who develop YMDD mutants than in those without mutants. However, there is no useful serum marker that can predict early emergence of mutants during LAM therapy. Analysis of patients who were treated with entecavir (n=7) and LAM (n=36) showed some patients had high serum levels of HBV RNA. Median serum levels of HBV RNA were significantly higher in patients in whom the YMDD mutant had emerged within 1 year (n=6, 1.688 log copies/ml) than in those in whom the YMDD mutant emerged more than 1 year after treatment (n=12, 0.456 log copies/ml, P=0.0125) or in whom the YMDD mutant never emerged (n=18, 0.688 log copies/ml, P=0.039). Our results suggest that HBV RNA is a valuable predictor of early occurrence of viral mutation during LAM therapy.

Quantitative analysis of HBV cccDNA from clinical specimens: correlation with clinical and virological response during antiviral therapy

Attempts to investigate changes in various forms of intrahepatic hepatitis B virus (HBV) DNA during antiviral therapy have been hampered by limitations in technologies and scarcity of adequate tissue for analysis. We used a sensitive, specific assay to detect and quantitate covalently closed circular DNA (cccDNA) from total intrahepatic HBV DNA in clinical liver specimens. Total HBV DNA and cccDNA from 21 needle-biopsy specimens were quantified, with levels ranging from 0.1 to 9.8 copies/cell and 0.3 to 491.0 copies/cell, respectively. Then, we performed the same determinations on baseline and week-52 liver needle-biopsy specimens from eight patients enrolled in a clinical trial and evaluated the association between intrahepatic HBV DNA levels and serological and virological endpoints. In most patients, levels of intrahepatic HBV DNA, including cccDNA, decreased over the 52-week study, regardless of therapy or serological outcome. Higher ratios of cccDNA to total HBV DNA were detected at week 52 than at baseline indicating a shift in predominance of nonreplicating virus in posttreatment specimens. In patients who achieved treatment-related or spontaneous hepatitis B e antigen (HBeAg) responses, including those harbouring tyrosine-methionine-aspartate-aspartate-mutant HBV, levels of intrahepatic and serum HBV DNA suppression were greater than those in patients without HBeAg responses. In conclusion, this pilot study of intrahepatic HBV replicative forms in patients with chronic hepatitis B indicated that total intrahepatic and, specifically, cccDNA levels are not static but change as a reflection of serological and virological events.

Efficacy of thymosin alpha-1 and interferon alpha in treatment of chronic viral hepatitis B: a randomized controlled study

AIM

To observe the efficiency and safety of thymosin-alpha1 treatment in patients with hepatitis B e antigen (HBeAg) and HBV DNA positive chronic hepatitis.

METHODS

Sixty-two patients were randomly divided into groups A and B. The patients in group A received subcutaneous injection of 1.6 mg thymosin-alpha1, twice a week (T-alpha1 group) for six months, and the patients in group B received 5 MU interferon alpha (IFN-alpha) each day for fifteen days, then three times weekly (IFN-alpha group) for six months. The results between two groups treated with and the group untreated with IFN-alpha which was followed up for 12 mo (historical control group consisting of 30 patients) were compared, and three groups were comparable between each other (P>0.05) at baseline (age, sex, clinical history, biochemical, and serological parameters).

RESULTS

At the end of treatment, complete response, which was defined as alanine aminotransferase (ALT) normalization and HBV DNA and HBeAg loss, occurred in 9 of 29 (31.0%) patients in the T-alpha1 group and in 15 of 33 (45.5%) patients in the IFN-alpha group (chi2=1.36, P>0.05). After a follow-up period of six months, a complete response was observed in 14 of 29 (48.3%) patients in the T-alpha1 group and in 9 of 33 (27.3%) patients in the IFN-alpha group (chi2=2.93, P>0.05). Compared with the results observed in the historical control (HC) group untreated with IFN-alpha which was followed up for 12 mo, the rate of complete response was significantly higher in IFN-alpha group at the end of therapy (1 of 30 vs 15 of 33, chi2=14.72, P<0.001) and in the T-alpha1 group at the end of follow-up (1 of 30 vs 14 of 29, chi2=15.71, P<0.001). In T-alpha1 and IFN-alpha treatment groups, the area under (the plasma concentration time) curve (AUC) of negative HBV DNA and HBeAg was 34%, 17%, 31% and 19% smaller than that in the HC group. By the end of the follow-up period, the proportions of ALT normalization and negative HBV DNA in the T-alpha1 group were significantly higher than those in the IFN-alpha and HC groups. The odds of ALT normalization and negative HBV DNA at the end of the follow-up was three-fold higher in the T-alpha1 group than in the IFN-alpha group. Unlike IFN-alpha, T-alpha1 was well tolerated by all patients, and no side effects appeared in T-alpha1 group.

CONCLUSION

The results suggest that a 6-mo course of T-alpha1 therapy is effective and safe in patients with chronic hepatitis B. T-alpha1 is able to reduce HBV replication in patients with chronic hepatitis B. Furthermore, T-alpha1 is better tolerated than IFN-alpha and can gradually induce more sustained ALT normalization and HBV DNA and HBeAg loss. However, a response rate of 48.3% is still less ideal. A more effective therapeutic approach warrants further study.

Recommendations and potential future options in the treatment of hepatitis B

The natural history of chronic hepatitis B should be clearly defined before appropriate recommendations for treatment can be advocated. In patients who acquire the disease in early life, the complications of chronic hepatitis B continue to occur as a result of prolonged insidious damage to the liver, even in the low viraemic phase. Treatment that ends with hepatitis B e antigen seroconversion with hepatitis B virus DNA levels just below 10(5) copies/ml may not be sufficient. Patients with mild elevation of alanine aminotransferase levels are already at considerable risk of developing complications. Treatment strategy should aim at maximal and prolonged viral suppression to the lowest possible hepatitis B virus DNA levels. Nucleotide/nucleoside analogues will become the mainstay of treatment. Future treatment strategic plans should target maximising antiviral potency and minimising the chance of drug resistance.

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Significance of viral load, core promoter/precore mutations and specific sequences of polymerase gene in HBV-infected patients on 3-year lamivudine treatment

BACKGROUND

Comprehensive study on viral factors predicting treatment responsiveness to lamivudine is lacking.

AIMS

To define the significance of various viral factors and changes of viral population with lamivudine treatment.

PATIENTS AND METHODS

Hepatitis B virus (HBV) DNA levels at baseline, week 24, 52 and year 3 were measured in 80 patients on continuous lamivudine therapy for 3 years. Genotypes, core promoter/precore mutations, YMDD mutations, polymorphic sequence of polymerase gene (rt91 I/L, rt256S/C) were determined at baseline, week 12, 24 and 52. YMDD mutations were also determined at year 3.

RESULTS

High alanine aminotransferase levels and presence of core promoter/ precore mutations at baseline were associated with higher chance of achieving HBV DNA <1,000 copies/ml (good response) and higher rate of hepatitis Be antigen (HBeAg) seroconversion at week 52. Achieving HBV DNA levels <1,000 copies/mi at week 24 as well as baseline core promoter/precore mutations were associated with higher chance of achieving good response, higher rate of HBeAg seroconversion and lower rate of YMDD mutations at year 3. Lamivudine reversed core promoter mutations to wild type in 25% of patients. All 5 patients with rt256C had poor HBV DNA response, persistent HBeAg and YMDD mutations by year 3. There was no difference in treatment response between patients with genotype B and C.

CONCLUSIONS

Achieving HBV DNA levels <1,000 copies/ml at 24 week is the best target for short- and long-term treatment efficacy. Core promoter and precore mutations were associated with better treatment outcome, and rt256C polymorphism in the polymerase gene with poor response.

Detection of hepatitis B virus cccDNA with modified polymerase chain reaction

AIM: To establish a simple and fast hepatitis B virus covalently closed circular DNA(cccDNA) detecting method based on polymerase chain reaction(PCR) with satisfactory sensitivity and specificity.

METHODS: The cccDNA and the relaxed circular DNA (rcDNA) were extracted from HepG2.2.15 cells and supernatant, respectively, and then purified. Two pairs of specific PCR primes were designed to cover the single strand area of rcDNA. And two pairs of non-specific PCR primes were designed to cover the double strand area of rcDNA. Before and after digested by single-strand-specific mung bean nuclease(MBN), cccDNA and rcDNA samples were amplified by specific primes and non-specific primes. Whether the digested cccDNA can be amplified by specific primes, without amplifying the digested rcDNA, was observed. The PCR parameters such as substrate amount and circulation times were changed during amplification. The HBV genome plasmid was used as control; and the HBV samples from patient with hepatitis B was used for practical test.

RESULTS: Different amounts of rcDNA template were amplified by specific and non-specific primes. More than 10⁴ and 10² rcDNA template molecules were amplified by two pairs of specific and non-specific primes, respectively. The specific primes could not discriminate between rcDNA and cccDNA when the template molecules were overabundant. Before and after the digestion by MBN, different amounts of cccDNA were amplified by specific and non-specific primes; and after the digestion, rcDNA templates were amplified by non-specific primes, but not by specific primes. With this strategy, we found the virus samples from the serum of the patient with chronic hepatitis B contained mainly rcDNA and a small quantity of cccDNA, while the samples from hepatocytes contained mainly cccDNA.

CONCLUSION: The combination of MBN selective digestion and specific PCR amplification of the cccDNA is a simple, fast, sensitive and specific method for the detection of HBV cccDNA.