Replication of clinical hepatitis B virus isolate and its application for selecting antiviral agents for chronic hepatitis B patients

AIM: To establish a cell model harboring replicative clinical hepatitis B virus (HBV) isolates and evaluate its application in individualized selection of anti-HBV agents for chronic hepatitis B (CHB) patients. METHODS: The full-length HBV genomic DNA from 8 CHB patients was amplified by polymerase chain reaction (PCR). All the patients were treated with lamivudine for at least seven months and finally became resistant to lamivudine. The amplified HBV DNA fragments were inserted into pHY106 vectors by Sap Ⅰ?digestion. The recombinant plasmids containing 1.1 copies of HBV genome were transiently transfected into Huh7 cell line, and the levels of HBsAg, HBeAg and intercellular HBV replicative intermediates were determined by ELISA and Southern blot analysis, respectively, with or without lamivudine and adefovir treatment. The antiviral treatment with adefovir was administered to the patients and analyzed in parallel. RESULTS: A total of 25 independent HBV isolateswere obtained from the sera of 8 patients, each patient had at least two isolates. One isolate from each individual was selected and subcloned into pHY106 vector, including 5 isolates with YVDD mutation and 3 isolates with YIDD mutation. All recombinant plasmids harboring HBV isolates were transfected into Huh7 cells. The results indicated that HBV genome carried in HBV replicons of clinical HBV isolates could effectively replicate and express in Huh7 cells. Adefovir, but not lamivudine, inhibited HBV replication both in vitro and in vivo, and in vitro inhibition was dose-dependent. CONCLUSION: The novel method described herein enables individualized selection of anti-HBV agents in clinic and is useful in future studies of antiviral therapy for CHB.

慢性乙型肝炎患者接受核(苷)酸类似物抗病毒治疗后血清HBV-DNA的表达及临床意义

目的探讨慢性乙型肝炎(CHB)患者接受核(苷)酸类似物(NAs)抗病毒治疗后血清乙型肝炎病毒脱氧核糖核酸(HBV-DNA)的表达及临床意义。方法回顾性分析2021年1月至2022年10月河南省人民医院83例采用NAs抗病毒治疗的CHB患者临床资料,根据血清学应答标准将其分为应答组(46例)和未应答组(37例)。比较两组基线资料、治疗前及治疗3、6、12个月时血清HBV-DNA水平;绘制受试者工作特征(ROC)曲线,以曲线下面积(AUC)检验血清HBV-DNA对CHB患者NAs抗病毒治疗未应答的预测价值。结果治疗前,应答组和未应答组HBV-DNA比较,差异无统计学意义(P>0.05);两组治疗前至治疗12个月的HBV-DNA呈下降趋势,组间、时点、交互效应有统计学意义(P<0.05)。绘制ROC曲线显示,治疗3个月时HBV-DNA对CHB患者NAs抗病毒治疗未应答的预测价值较低(AUC=0.694,P=0.002),治疗6个月时HBV-DNA对CHB患者NAs抗病毒治疗未应答具有一定预测价值(AUC=0.751,P<0.001)。结论血清HBV-DNA表达在CHB患者NAs抗病毒治疗前后变化明显,且治疗6个月时血清HBV-DNA可作为抗病毒治疗未应答的预测指标。

Prevention and management of hepatitis B virus reactivation in patients with hematological malignancies in the targeted therapy era

Hepatitis due to hepatitis B virus(HBV)reactivation can be serious and potentially fatal,but is preventable.HBV reactivation is most commonly reported in patients receiving chemotherapy,especially rituximab-containing therapy for hematological malignancies and those receiving stem cell transplantation.Patients with inactive and even resolved HBV infection still have persistence of HBV genomes in the liver.The expression of these silent genomes is controlled by the immune system.Suppression or ablation of immune cells,most importantly B cells,may lead to reactivation of seemingly resolved HBV infection.Thus,all patients with hematological malignancies receiving anticancer therapy should be screened for active or resolved HBV infection by blood tests for hepatitis B surface antigen(HBsAg)and antibody to hepatitis B core antigen.Patients found to be positive for HBsAg should be given prophylactic antiviral therapy.For patients with resolved HBV infection,there are two approaches.The first is pre-emptive therapy guided by serial HBV DNA monitoring,and treatment with antiviral therapy as soon as HBV DNA becomes detectable.The second approach is prophy-lactic antiviral therapy,particularly for patients receiving high-risk therapy,especially anti-CD20 monoclonal antibody or hematopoietic stem cell transplantation.Entecavir and tenofovir are the preferred antiviral choices.Many new effective therapies for hematological malignancies have been introduced in the past decade,for example,chimeric antigen receptor(CAR)-T cell therapy,novel monoclonal antibodies,bispecific antibody drug conjugates,and small molecule inhibitors,which may be associated with HBV reactivation.Although there is limited evidence to guide the optimal preventive measures,we recommend antivi-ral prophylaxis in HBsAg-positive patients receiving novel treatments,including Bruton’s tyrosine kinase inhibitors,B-cell lymphoma 2 inhibitors,and CAR-T cell therapy.Further studies are needed to determine the risk of HBV reactivation with these agents and the best prophylactic strategy.

Past,present,and future of long-term treatment for hepatitis B virus

The estimated world prevalence of hepatitis B virus(HBV)infection is 316 million.HBV infection was identified in 1963 and nowadays is a major cause of cirrhosis and hepatocellular carcinoma(HCC)despite universal vaccination programs,and effective antiviral therapy.Long-term administration of nucleos(t)ide analogues(NA)has been the treatment of choice for chronic hepatitis B during the last decades.The NA has shown a good safety profile and high efficacy in controlling viral replication,improving histology,and decreasing the HCC incidence,decompensation,and mortality.However,the low probability of HBV surface antigen seroclearance made necessary an indefinite treatment.The knowledge,in recent years,about the different phases of the viral cycle,and the new insights into the role of the immune system have yielded an increase in new therapeutic approaches.Consequently,several clinical trials evaluating combinations of new drugs with different mechanisms of action are ongoing with promising results.This integrative literature review aims to assess the knowledge and major advances from the past of hepatitis B,the present of NA treatment and withdrawal,and the future perspectives with combined molecules to achieve a functional cure.

Antiviral therapy and resistance with hepatitis B virus infection

Hepatitis B virus （HBV） infection is still the most common cause of hepatocellular carcinoma and liver drrhosis world wide. Recently, however, there has been quite dramatic improvement in the understanding of HBV assodated liver disease and its treatment. It has become dear that high viral replication is a major risk factor for the development of both cirrhosis and hepatocellular carcinoma. Early studies have shown lamivudine lowers the risk of HBV associated complications. There are currently three nucleos（t）ides licensed, in addition to interferon, and there are more drugs coming to the market soon. Interferon or its pegylated counterpart are still the only options for treatment with defined end points, while nudeos（t）ides therapy is used mostly for long term treatment. Combination therapies have not been shown to be superior to monotherapy in naive patients, however, the outcome depends on how the end point is defined. Interferon plus lamivudine achieves a higher viral suppression than either treatment alone, even though Hbe-seroconversion was not different after a one year treatment. HBV-genotypes emerge as relevant factors, with genotypes ＂A＂ and ＂B＂ responding relatively well to interferon, achieving up to 20% HBsAg clearance in the case of genotype ＂A＂. In addition to having a defined treatment duration, interferon has the advantage of lack- ing resistance selection, which is a major drawback for lamivudine and the other nucleos（t）ides. The emergence of resistance against adefovir and entecavir is some- what slower in na＇fve compared to lamivudine resistant patients. Adefovir has a low resistance profile with 3%, 9%, 18%, and 28% after 2, 3, 4, and 5 years, respectively, while entecavir has rarely produced resistance in naive patients for up to 3 years.

Evaluation of adherence to oral antiviral hepatitis B treatment using structured questionnaires

AIM:To assess adherence rates to nucleos(t)ide analogues(NUCs) therapy in patients with chronic hepatitis B virus infection and determine factors associated with adherence.METHODS:The questionnaire study was conducted in the liver clinics at Concord Repatriation General Hospital.All patients who were currently taking one or more NUCs were asked to complete a structured,selfadministered 32-item questionnaire.Adherence was measured using visual analogue scales.The patient’s treating clinician was also asked to assess their patient’s adherence via a structured questionnaire.RESULTS:A total of 80 patients completed the questionnaire.Sixty six percent of the patients(n = 49) reported optimal adherence whilst 25(33.8%) graded their adherence to NUCs as suboptimal.Thirty four(43%) patients reported to have omitted taking their NUCs sometime in the past.Recent non-adherence was uncommon.Amongst the patients who reported skipping medications,the most common reason cited was 'forgetfulness'(n = 27,56.25%).Other common reasons included:ran out of medications(n = 5,10.42%),being too busy(n = 4,8.33%) and due to a change in daily routine(n = 5,10.42%).Patients who reported low adherence to other prescription pills were also more likely to miss taking NUCs(P = 0.04).Patients who were under the care of a language-discordant clinician were also more likely to report suboptimal adherence to NUCs(P = 0.04).CONCLUSION:Adherence rates were much less than that expected by the physician and has potential adverse affect on long term outcome.Communication and education appear central and strategies need to be implemented to improve ongoing adherence.

Long term outcome of antiviral therapy in patients with hepatitis B associated decompensated cirrhosis

AIM To investigate survival rate and incidence of hepatocellular carcinoma(HCC) in patients with decompensated cirrhosis in the antiviral era.METHODS We used the Korean Health Insurance Review and Assessment. Korea's health insurance system is a public single-payer system. The study population consisted of 286871 patients who were prescribed hepatitis B antiviral therapy for the first time between 2007 and 2014 in accordance with the insurance guidelines.Overall, 48365 antiviral treatment-na?ve patients treated between 2008 and 2009 were included, and each had a follow-up period ≥ 5 years. Data were analyzed for the 1 st decompensated chronic hepatitis B(CHB) and treatment-na?ve patients(n = 7166). RESULTS The mean patient age was 43.5 years. The annual mortality rates were 2.4%-19.1%, and 5-year cumulative mortality rate was 32.6% in 1^(st) decompensated CHB treatment-na?ve subjects. But the annual mortality rates sharply decreased to 3.4%(2.4%-4.9%, 2-5 year) after one year of antiviral treatment. Incidence of HCC at first year was 14.3%, the annual incidence of HCC decreased to 2.5%(1.8%-3.7%, 2-5 year) after one year. 5-year cumulative incidence of HCC was 24.1%. Recurrence rate of decompensated event was 46.9% at first year, but the annual incidence of second decompensation events in decompensated CHB treatment-na?ve patients was 3.4%(2.1%-5.4%, 2-5 year) after one year antiviral treatment. 5-year cumulative recurrence rate of decompensated events was 60.6%. Meanwhile, 5-year cumulative mortality rate was 3.1%, and 5-year cumulative incidence of HCC was 11.5% in compensated CHB treatment-na?ve patients.CONCLUSION Long term outcome of decompensated cirrhosis treated with antiviral agent improved much, and incidence of hepatocellular carcinoma and mortality sharply decreased after one year treatment.

Hepatitis B reactivation in patients receiving direct-acting antiviral therapy or interferon-based therapy for hepatitis C:A systematic review and meta-analysis

AIM To assess the incidence of hepatitis B virus(HBV) reactivation in patients receiving direct-acting antiviral agent(DAA)-based therapy or interferon(IFN)-based therapy for hepatitis C and the effectiveness of preemptive antiHBV therapy for preventing HBV reactivation.METHODS The Pub Med, MEDLINE and EMBASE databases were searched, and 39 studies that reported HBV reactivation in HBV/hepatitis C virus coinfected patients receiving DAAbased therapy or IFN-based therapy were included. The primary outcome was the rate of HBV reactivation. The secondary outcomes included HBV reactivation-related hepatitis and the effectiveness of preemptive anti-HBV treatment with nucleos(t)ide analogues. The pooled effects were assessed using a random effects model. RESULTS The rate of HBV reactivation was 21.1% in hepatitis Bsurface antigen(HBs Ag)-positive patients receiving DAAbased therapy and 11.9% in those receiving IFN-based therapy. The incidence of hepatitis was lower in HBs Agpositive patients with undetectable HBV DNA compared to patients with detectable HBV DNA receiving DAA therapy(RR = 0.20, 95%CI: 0.06-0.64, P = 0.007). The pooled HBV reactivation rate in patients with previous HBV infection was 0.6% for those receiving DAA-based therapy and 0 for those receiving IFN-based therapy, and none of the patients experienced a hepatitis flare related to HBV reactivation. Preemptive anti-HBV treatment significantly reduced the potential risk of HBV reactivation in HBs Agpositive patients undergoing DAA-based therapy(RR = 0.31, 95%CI: 0.1-0.96, P = 0.042).CONCLUSION The rate of HBV reactivation and hepatitis flare occurrence is higher in HBs Ag-positive patients receiving DAA-based therapy than in those receiving IFN-based therapy, but these events occur less frequently in patients with previous HBV infection. Preemptive anti-HBV treatment is effective in preventing HBV reactivation.

Emerging antivirals for the treatment of hepatitis B

Chronic infection with hepatitis B virus(HBV)constitutes a major global public health threat,causing substantial disease burdens such as liver cirrhosis and hepatocellular carcinoma,thus representing high unmet medical needs.Currently available therapies are safe,well tolerated,and highly effective in decreasing viremia and improving measured clinical outcomes with low rates of antiviral resistance.However,long-term management remains a clinical challenge,mainly due to the slow kinetics of HBV surface antigen clearance.In this article,we review emerging antivirals directed at novel targets derived from mechanisms of viral cellular entry,viral replication,viral assembly,and the host immune response,leading to preclinical and clinical trials for possible future therapeutic intervention.The recent therapeutic advances in the development of all categories of HBV inhibitors may pave the way for regimens of finite duration that result in long-lasting control of chronic hepatitis B infection.

Inhibition of hepatitis B virus replication by pokeweed antiviral protein in vitro

AIM: To explore the inhibitory effects of pokeweed antiviral protein seed (PAP-S) and PAP encoded by a eukaryotic expression plasmid on hepatitis B virus (HBV) replication in vitro. METHODS: HepG2 2.2.15 cells in cultured medium were treated with different concentrations of PAP-S. HBsAg, HBeAg and HBV DNA in supernatants were determined by ELISA and fluorescent quantitative PCR respectively. MTT method was used to assay for cytotoxicity. HepG2 were cotransfected with various amounts of PAP encoded by a eukaryotic expression plasmid and replication competent wild-type HBV 1.3 fold over- length plasmid. On d 3 after transfection, HBsAg and HBeAg were determined by using ELISA. Levels of HBV core-associated DNA and RNA were detected by using Southern and Northern blot, respectively. RESULTS: The inhibitory effects of PAP-S on HBsAg, HBeAg and HBV DNA were gradually enhanced with the increase of PAP concentration. When the concentration of PAP-S was 10 μg/mL, the inhibition rates of HBsAg, HBeAg and HBV DNA were 20.9%, 30.2% and 50%, respectively. After transfection of 1.0 μg and 2.0 μg plasmid pXF3H-PAP, the levels of HBV nucleocapside- associated DNA were reduced by 38.0% and 74.0% respectively, the levels of HBsAg in the media by 76.8% and 99.7% respectively, and the levels of HBeAg by 72.7% and 99.3% respectively as compared with controls. Transfection with 2 μg plasmid pXF3H-PAP reduced the levels of HBV nucleocapside-associated RNA by 69.0%.CONCLUSION: Both PAP-S and PAP encoded by a eukaryotic expression plasmid could effectively inhibit HBV replication and antigen expression in vitro, and the inhibitory effects were dose-dependent.

Retreatment of patients with treatment failure of directacting antivirals: Focus on hepatitis C virus genotype 1b

The recent development of direct-acting antiviral agents(DAAs) against hepatitis C virus(HCV) infection could lead to higher sustained virological response(SVR) rates, with shorter treatment durations and fewer adverse events compared with regimens that include interferon. However, a relatively small proportion of patients cannot achieve SVR in the first treatment, including DAAs with or without peginterferon and/or ribavirin. Although retreatment with a combination of DAAs should be conducted for these patients, it is more difficult to achieve SVR when retreating these patients because of resistance-associated substitutions(RASs) or treatment-emergent substitutions. In Japan, HCV genotype 1 b(GT1 b) is founded in 70% of HCVinfected individuals. In this minireview, we summarize the retreatment regimens and their SVR rates for HCV GT1 b. It is important to avoid drugs that target the regions targeted by initial drugs, but next-generation combinations of DAAs, such as sofosbuvir/velpatasvir/voxilaprevir for 12 wk or glecaprevir/pibrentasvir for 12 wk, are proposed to be potential solution for the HCV GT1 b-infected patients with treatment failure, mainly on a basis of targeting distinctive regions. Clinicians should follow the new information and resources for DAAs and select the proper combination of DAAs for the retreatment of HCV GT1 b-infected patients with treatment failure.

Telbivudine:A new treatment for chronic hepatitis B

Three hundred and fifty million people worldwide are estimated to be chronically infected with hepatitis B virus. 15%-40% of these subjects will develop cirrhosis, liver failure or hepatocellular carcinoma during their life. The treatment of chronic hepatitis B has improved dramatically over the last decade merits to the advent of nucleoside/nucleotide analogues and the use of pegylated interferons. Approved drugs for chronic hepatitis B treatment include： standard interferon- alpha 2b, pegylated interferon-alpha 2a, lamivudine, adefovir dipivoxil, and entecavir. Unfortunately, these agents are not effective in all patients and are associated with distinct side effects. Interferons have numerous side effects and nucleoside or nucleotide analogues, which are well tolerated, need to be used for prolonged periods, even indefinitely. However, prolonged treatment with nucleoside or nucleotide analogues is associated with a high rate of resistance. Telbivudine is a novel, orally administered nucleoside analogue for use in the treatment of chronic hepatitis B. In contrast to other nucleoside analogues, Telbivudine has not been associated with inhibition of mammalian DNA polymerase with mitochondrial toxicity. Telbivudine has demonstrated potent activity against hepatitis B with a significantly higher rate of response and superior viral suppression compared with lamivudine, the standard treatment. Telbivudine has been generally well tolerated, with a low adverse effect profile, and at its effective dose, no dose- limiting toxicity has been observed. Telbivudine is one of the most potent antiviral agents for chronic hepatitis B virus and was approved by the FDA in late 2006.

Inhibition of hepatitis B virus by oxymatrine in vivo

AIM To investigate the anti-HBV effect ofoxymatrine (oxy) in vivo.METHODS HBV transgenic mice were producedby micro-injection of a 4.2kb fragmentcontaining the complete HBV genomes.Expression level of HBsAg and HBcAg in thetransgenic mice liver was determined byimmunohistochemical assay.RESULTS Four groups (6 mice in each group)were injected intraperitoneally with oxy at thedosage of 100,200, and 300 mg/kg or with salineonce a day for 30 days. Both HBsAg and HBcAgwere positive in livers of all the six mice in thecontrol group (injected with saline), and werepositive in livers of two mice in 100 mg/kg groupand 300mg/kg group. In 200mg/kg group,HBsAg and HBcAg were negative in livers of allthe six mice. Based on the results, 200 mg/kg isthe ideal dosage to explore the effect of oxy atdifferent time points. According to the oxytreatment time, mice were divided into fourgroups: 10 d, 20 d, 30 d and 60 d (4 mice in eachgroup). Each mouse underwent liver biopsy twoweeks before the treatment of oxy. Down-regulation of HBsAg and HBcAg appeared aftertreatment of oxymatrine for 10 d and 20 d, Dane-like particles disappeared after the treatment ofoxy for 20d under electron microscopy,however, the expression level of HBsAg andHBcAg returned to normal 60 d later after oxytreatment.CONCLUSION oxymatrine can reduce thecontents of HBsAg and HBcAg in transgenic miceliver, longer treatment time and larger dosagedo not yield better effects.

Survival and prognostic factors in hepatitis B virus-related acute-on-chronic liver failure

AIM:To investigate the survival rates and prognostic factors in patients with hepatitis B virus-related acuteon-chronic liver failure(HBV-ACLF).METHODS:Clinical data in hospitalized patients with HBV-ACLF admitted from 2006 to 2009 were retrospectively analyzed.Their general conditions and survival were analyzed by survival analysis and Cox regression analysis.RESULTS:A total of 190 patients were included in this study.The overall 1-year survival rate was 57.6%.Patients not treated with antiviral drugs had a significantly higher mortality[relative risk(RR)=0.609,P=0.014].The highest risk of death in patients with ACLF was associated with hepatorenal syndrome(HRS)(RR=2.084,P=0.026),while other significant factors were electrolyte disturbances(RR=2.062,P=0.010),and hepatic encephalopathy(HE)(RR=1.879,P<0.001).CONCLUSION:Antiviral therapy has a strong effect on the prognosis of the patients with HBV-ACLF by improving their 1-year survival rate.HRS,electrolyte disturbances,and HE also affect patient survival.

Novel approaches towards conquering hepatitis B virus infection

Currently approved treatments for hepatitis B virus （HBV） infection include the immunomodulatory agent, IFN-α, and nucleos（t）ide analogues. Their efficacy is limited by their side effects, as well as the induction of viral mutations that render them less potent. It is thus necessary to develop drugs that target additional viral antigens. Chemicals and biomaterials by unique methods of preventing HBV replication are currently being developed, including novel nucleosides and newly synthesized compounds such as capsid assembling and mRNA transcription inhibitors. Molecular therapies that target different stages of the HBV life cycle will aid current methods to manage chronic hepatitis B （CriB） infection. The use of immunomodulators and gene therapy are also under consideration. This report summarizes the most recent treatment possibilities for CHB infection. Emerging therapies and their potential mechanisms, efficacy, and pitfalls are discussed.

Inhibition of hepatitis B virus production by Boehmeria nivea root extract in HepG2 2.2.15 cells

AIM: To explore the anti-hepatitis B virus (HBV) effects of Boehmeria nivea (B. nivea) root extract (BNE) by using the HepG2 2.2.15 cell model system. METHODS: Hepatitis B surface antigen (HBsAg), hepatitis B virus e antigen (HBeAg), and HBV DNA were measured by using ELISA and real-time PCR, respectively. Viral DNA replication and RNA expression were determined by using Southern and Northern blot, respectively. RESULTS: In HepG2 2.2.15 cells, HBeAg (60%, P < 0.01) and particle-associated HBV DNA (> 99%, P < 0.01) secretion into supernatant were significantly inhibited by BNE at a dose of 100 mg/L, whereas the HBsAg was not inhibited. With different doses of BNE, the reduced HBeAg was correlated with the inhibition of HBV DNA. The anti-HBV effect of BNE was not caused by its cytotoxicity to cells or inhibition of viral DNA replication and RNA expression. CONCLUSION: BNE could effectively reduce the HBV production and its anti-HBV machinery might differ from the nucleoside analogues.

Long-term alpha interferon and lamivudine combination therapy in non-responder patients with anti-HBe-positive chronic hepatitis B:Results of an open,controlled trial

AIM: To investigate the safety and efficacy of long-term combination therapy with alpha interferon and lamivudine in non-responsive patients with anti-HBe-positive chronic hepatitis B.METHODS: 34 patients received combination treatment (1 month lamivudine, 12 month lamivudine+interferon, 6month lamivudine), 24 received lamivudine (12 months),24 received interferon (12 months). Interferon was administered at 6 MU tiw and lamivudine at 100 mg orally once daily. Patients were followed up for 6 months after treatment.RESULTS: At the end of treatment, HBV DNA negativity rates were 88 % with lamivudine+interferon, 99 % with lamivudine and 55 % with interferon, (P=0.004, combination therapy vs. interferon, and P=0.001 lamivudine vs.interferon), and serum transaminase normalization rates were 84 %, 91% and 53 % (P=0.01 combination therapy vs. interferon, and P=0.012 lamivudine vs. interferon). Six months later, HBV DNA negativity rates were 44 % with lamivudine+interferon, 33 % with lamivudine and 25 % with interferon, and serum transaminase normalization rates were 61%, 42 % and 45 %, respectively, without statistical significance. No YMDD variants were observed with lamivudine+interferon (vs. 12 % with lamivudine). The combination therapy appeared to be safe. CONCLUSION: Although viral clearance and transaminase normalization are slower with long-term lamivudine+interferon than that with lamivudine alone, the combination regimen seems to provide more lasting benefits and to protect against the appearance of YMDD variants. Studies with other regimens regarding sequence and duration are needed.

Application of hepatitis B virus replication mouse model

AIM:To evaluate the value of the hepatitis B virus(HBV) replication mouse model with regard to several aspects of the study of HBV biology.METHODS:To evaluate the HBV replication mouse model in detecting the efficacy of anti-HBV agents,the interferon inducer polyinosinic-polytidylin acid(polyIC) and nucleotide analogues adefovir and entecavir were administered to mice injected with wild type pHBV4.1,and the inhibiting effect of these agents on HBV DNA replication was evaluated.To identify the model's value in a replication ability study of HBV drug-resistant mutants and a HBx-minus mutant,telbivudine resistance mutants(rtM204I,ayw subtype),adefovir resistance mutants(rtA181V + rtN236T,ayw subtype) and HBxminus mutants were injected respectively,and their corresponding HBV DNA replication intermediates in mouse liver were assessed.RESULTS:Compared with the wild type HBV replication mouse model without antiviral agent treatment,the HBV DNA replication intermediates of the polyICtreated group were decreased 1-fold;while in the entecavir-and adefovir-treated groups,the levels of HBV DNA replication intermediates were inhibited 13.6-fold and 1.4-fold,respectively.For the mouse models injected with telbivudine resistance mutant,adefovir resistance mutant and HBx-minus mutant,HBV DNA replication intermediates could still be detected,but the levels of HBV DNA replication intermediates of these mutants decreased 4.5-fold,5.6-fold and 2.9-fold respectively,compared with the mouse model with wild type HBV plasmid.CONCLUSION:The HBV replication mouse model we established was a useful and convenient tool to detect the efficacy of antiviral agents and to study the replication ability of HBV mutants in vivo.

Current trends in management of hepatitis B virus reactivation in the biologic therapy era

Hepatitis B virus (HBV) reactivation represents an emerging cause of liver disease in patients undergoing treatment with biologic agents. In particular, the risk ofHBV reactivation is heightened by the use monoclonalantibodies, such as rituximab (anti-CD20) and alemtuzumab (anti-CD52) that cause profound and longlasting immunosuppression. Emerging data indicatethat HBV reactivation could also develop following theuse of other biologic agents, such as tumor necrosis factor (TNF)-α inhibitors. When HBV reactivation is di-agnosed, it is mandatory to suspend biologic treatmentand start antiviral agents immediately. However, preemptive antiviral therapy prior to monoclonal antibodyadministration is crucial in preventing HBV reactivationand its clinical consequences. Several lines of evidencehave shown that risk of HBV reactivation is greatlyreduced by the identifi cation of high-risk patients andthe use of prophylactic antiviral therapy. In this article, we discuss current trends in the management of HBV reactivation in immunosuppressed patients receiving biologic therapy, such as rituximab, alemtuzumab and TNF-α antagonists.

Prediction models for development of hepatocellular carcinoma in chronic hepatitis B patients

Chronic hepatitis B(CHB)-related hepatocellular carcinoma(HCC)is a major health problem in Asian-Pacific regions.Antiviral therapy reduces,but does not completely prevent,HCC development.Thus,there is a need for accurate risk prediction to assist prognostication and decisions on the need for antiviral therapy and HCC surveillance.A few risk scores have been developed to predict the occurrence of HCC in CHB patients.Initially,the scores were derived from untreated CHB patients.With the development and extensive clinical application of nucleos(t)ide analog(s)(NA),the number of risk scores based on treated CHB patients has increased gradually.The components included in risk scores may be categorized into host factors and hepatitis B virus factors.Hepatitis activities,hepatitis B virus factors,and even liver fibrosis or cirrhosis are relatively controlled by antiviral therapy.Therefore,variables that are more dynamic during antiviral therapy have since been included in risk scores.However,host factors are more difficult to modify.Most existing scores derived from Asian populations have been confirmed to be accurate in predicting HCC development in CHB patients from Asia,while these scores have not offered excellent predictability in Caucasian patients.These findings support that more relevant variables should be considered to provide individualized predictions that are easily applied to CHB patients of different ethnicities.CHB patients should receive different intensities of HCC surveillance according to their risk category.