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The quantification of infectious virus particles is fundamental to perform in vitro virology studies. To determine the number of hepatitis B virus (HBV) genome-containing particles in vitro, the genome equivalents (GEq) are measured using quantitative PCR (qPCR). However, in addition to infectious virions, HBV DNA-containing, non-infectious HBV particles are also produced in vitro, which can lead to an over-estimation of the number of infectious HBV particles when analyzed by qPCR. Here, we establish an end-point dilution assay that can precisely determine the number of infectious HBV particles. The cell-based HBV infection assay uses a 384-well plate format and enables the calculation of the 50% tissue culture infective dose (TCID 50 ) in a semi-automated manner. Cell culture-derived HBV (HBVcc), produced by either stable HBV-replicating cells (HepAD38) or HBV-infected HepG2-NTCP cells, as well as patient-derived HBV sera were serially diluted and used to infect naïve target cells. Applying the end-point dilution assay, we infected HepG2-NTCP cells with PEG precipitated HBV derived from HepAD38-and HepG2-NTCPsec+ cell supernatants, calculated the TCID 50 /mL, converted to plaque-forming units (PFUs), and generated the specific infectivity (ratio of PFU/GEq). As a result, a TCID 50 /mL of 7.22 × 10 6 and 2.16 × 10 6 , and the specific infectivity of 1/13,816 and 1/8798 were calculated for HepAD38 and HepG2-NTCPsec+ cell supernatants, respectively. The specific infectivity further increased by approximately 2-fold after removal of non-infectious "naked" particles by immunoprecipitation. Purification of HepAD38 cell supernatants by heparin columns increased the TCID 50 /mL and specific infectivity by 18- and 15-fold, respectively. Interestingly, non-purified patient-derived HBV sera from two individuals had a specific infectivity of 1/88 and 1/3609. After converting TCID 50 to multiplicity of infection (MOI) values, we inoculated HepG2-NTCP cells with HBVcc based on GEq or MOI values and demonstrated that MOI-based infection leads to more reproducible infection rates. Furthermore, the assay was validated using serially diluted lamivudine, an HBV replication inhibitor, inhibiting HBV DNA secretion and infectious viral progeny by approx. 56- and 470-fold, respectively. Interestingly, we identified dexmedetomidine (DMM), an alpha-2 adrenergic agonist, inhibiting the secretion of infectious viral progeny by approx. 6-fold, without interfering in the secretion of HBV DNA. Taken together, we developed an assay that is suitable for the standard quantification of infectious HBV particles. We identified DMM as a novel inhibitor that exclusively interferes with the secretion of infectious HBV particles without affecting the secretion of HBV genomes. This end-point dilution assay enables the precise determination of the number of infectious HBV particles, assessment of the specific infectivity and stability of HBV particles, and identification of novel classes of HBV inhibitors., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The risk of reactivation of resolved hepatitis B virus (HBV) in hepatitis B surface antigen (HBsAg)-negative multiple myeloma patients after daratumumab has not been reported. Among 93 patients with daratumumab treatment, reactivation occurred in 6 patients (6.5%) with one hepatic failure. This is the first report demonstrating a considerable risk of reactivation of resolved HBV after daratumumab., (© The Author(s) 2021. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Although hepatitis B virus (HBV) integration into the cellular genome is well known in HCC (hepatocellular carcinoma) patients, its biological role still remains uncertain. This study investigated the patterns of HBV integration and correlated them with TERT (telomerase reverse transcriptase) alterations in paired tumor and non-tumor tissues. Compared to those in non-tumors, tumoral integrations occurred less frequently but with higher read counts and were more preferentially observed in genic regions with significant enrichment of integration into promoters. In HBV-related tumors, TERT promoter was identified as the most frequent site (38.5% (10/26)) of HBV integration. TERT promoter mutation was observed only in tumors (24.2% (8/33)), but not in non-tumors. Only 3.00% (34/1133) of HBV integration sites were shared between tumors and non-tumors. Within the HBV genome, HBV breakpoints were distributed preferentially in the 3' end of HBx, with more tumoral integrations detected in the preS/S region. The major genes that were recurrently affected by HBV integration included TERT and MLL4 for tumors and FN1 for non-tumors. Functional enrichment analysis of tumoral genes with integrations showed enrichment of cancer-associated genes. The patterns and functions of HBV integration are distinct between tumors and non-tumors. Tumoral integration is often enriched into both human-virus regions with oncogenic regulatory function. The characteristic genomic features of HBV integration together with TERT alteration may dysregulate the affected gene function, thereby contributing to hepatocarcinogenesis.

Background/aims: The role of hepatitis B virus (HBV) integration into the host genome in hepatocarcinogenesis following hepatitis B surface antigen (HBsAg) seroclearance remains unknown. Our study aimed to investigate and characterize HBV integration events in chronic hepatitis B (CHB) patients who developed hepatocellular carcinoma (HCC) after HBsAg seroclearance., Methods: Using probe-based HBV capturing followed by next-generation sequencing technology, HBV integration was examined in 10 samples (seven tumors and three non-tumor tissues) from seven chronic carriers who developed HCC after HBsAg loss. Genomic locations and patterns of HBV integration were investigated., Results: HBV integration was observed in six patients (85.7%) and eight (80.0%) of 10 tested samples. HBV integration breakpoints were detected in all of the non-tumor (3/3, 100%) and five of the seven (71.4%) tumor samples, with an average number of breakpoints of 4.00 and 2.43, respectively. Despite the lower total number of tumoral integration breakpoints, HBV integration sites in the tumors were more enriched within the genic area. In contrast, non-tumor tissues more often showed intergenic integration. Regarding functions of the affected genes, tumoral genes with HBV integration were mostly associated with carcinogenesis. At enrollment, patients who did not remain under regular HCC surveillance after HBsAg seroclearance had a large HCC, while those on regular surveillance had a small HCC., Conclusion: The biological functions of HBV integration are almost comparable between HBsAg-positive and HBsAgserocleared HCCs, with continuing pro-oncogenic effects of HBV integration. Thus, ongoing HCC surveillance and clinical management should continue even after HBsAg seroclearance in patients with CHB.

Background: The effect of prophylactic antiviral therapy (AVT) on survival of patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) remains unknown. This study aimed to determine whether prophylactic AVT could improve long-term survival in patients undergoing transarterial chemotherapy (TAC)., Methods: Between 2002 and 2016, 2860 newly diagnosed HBV-related patients with HCC treated with TAC were screened to analyze 2 groups based on prophylactic use of antivirals. Treatment effects were analyzed using propensity score (PS) matching (1:1) separately for the entire cohort and each subgroup. The primary endpoint was overall survival., Results: A total of 1547 patients met the inclusion criteria and 1084 were PS matched for the 2 groups. Median follow-up duration was 16.55 months. In the entire unmatched cohort, patients receiving prophylactic AVT survived significantly longer than those who did not. Among AVT-untreated patients, baseline high viremia and HBV reactivation during treatment were significantly associated with shorter survival. Regarding types of antivirals, survival was significantly longer for patients receiving high-potency antivirals than those receiving low-potency antivirals. Survival differed with antiviral response. In the PS-matched cohort, the prophylactic AVT group survived significantly longer than the nonprophylactic group, irrespective of viral status or tumor stage. Prophylactic AVT remained an independent factor for survival. The association of prophylactic AVT with decreased risk of mortality persisted in patient subgroups after adjusting for baseline risk factors. Sensitivity analyses also confirmed estimated treatment effects., Conclusions: Prophylactic AVT is associated with significantly improved long-term survival among patients undergoing TAC. High-potency antivirals are indicated for this approach.Hepatitis B virus-associated morbidity is a well-known complication during transarterial chemotherapy (TAC). Our large-scale study demonstrated that prophylactic therapy with high-potency antivirals provides a significantly better survival in TAC-treated patients, irrespective of baseline viremia status or tumor stage., (© The Author(s) 2019. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail: journals.permissions@oup.com.)

Background & Aims: As hepatitis B virus (HBV) spreads through the infected liver it is simultaneously secreted into the blood. HBV-susceptible in vitro infection models do not efficiently amplify viral progeny or support cell-to-cell spread. We sought to establish a cell culture system for the amplification of infectious HBV from clinical specimens., Methods: An HBV-susceptible sodium-taurocholate cotransporting polypeptide-overexpressing HepG2 cell clone (HepG2-NTCPsec+) producing high titers of infectious progeny was selected. Secreted HBV progeny were characterized by native gel electrophoresis and electron microscopy. Comparative RNA-seq transcriptomics was performed to quantify the expression of host proviral and restriction factors. Viral spread routes were evaluated using HBV entry- or replication inhibitors, visualization of viral cell-to-cell spread in reporter cells, and nearest neighbor infection determination. Amplification kinetics of HBV genotypes B-D were analyzed., Results: Infected HepG2-NTCPsec+ secreted high levels of large HBV surface protein-enveloped infectious HBV progeny with typical appearance under electron microscopy. RNA-seq transcriptomics revealed that HBV does not induce significant gene expression changes in HepG2-NTCPsec+, however, transcription factors favoring HBV amplification were more strongly expressed than in less permissive HepG2-NTCPsec-. Upon inoculation with HBV-containing patient sera, rates of infected cells increased from 10% initially to 70% by viral spread to adjacent cells, and viral progeny and antigens were efficiently secreted. HepG2-NTCPsec+ supported up to 1,300-fold net amplification of HBV genomes depending on the source of virus. Viral spread and amplification were abolished by entry and replication inhibitors; viral rebound was observed after inhibitor discontinuation., Conclusions: The novel HepG2-NTCPsec+ cells efficiently support the complete HBV life cycle, long-term viral spread and amplification of HBV derived from patients or cell culture, resembling relevant features of HBV-infected patients., Lay Summary: Currently available laboratory systems are unable to reproduce the dynamics of hepatitis B virus (HBV) spread through the infected liver and release into the blood. We developed a slowly dividing liver-derived cell line which multiplies infectious viral particles upon inoculation with patient- or cell culture-derived HBV. This new infection model can improve therapy by measuring, in advance, the sensitivity of a patient's HBV strain to specific antiviral drugs., (Copyright © 2019 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Background: Hepatic osteodystrophy has been reported in patients with various chronic liver diseases, including liver cirrhosis. However, it has not been well investigated in patients with hepatitis B virus infection. The aim of this study was to investigate the association between hepatitis B surface antigen (HBsAg) seropositivity and bone mineral density (BMD) in a population representative of normal Koreans., Methods: Subjects with both HBsAg and BMD levels examined during the 2008-2010 Korea National Health and Nutrition Examination Surveys were included. HBsAg-seropositive (+) subjects were compared with those who were HBsAg-seronegative (-). BMD was measured at the lumbar spine and femur by dual-energy X-ray absorptiometry. Multivariable logistic regression was performed for BMD ., Results: In total, 11,306 participants were included in this study, among which 423 (3.7 %) were HBsAg(+): 153 premenopausal female (3.4 %), 83 postmenopausal female (3.5 %), and 187 male (4.2 %). Multivariable logistic regression analysis adjusted for age and body mass index showed that HBsAg(+) male had significantly lower BMD of the femoral neck than HBsAg(-) male (0.810 ± 0.009 vs. 0.827 ± 0.002 g/cm(2), p = 0.035). Further adjustment for waist circumference, smoking, drinking, exercise, income, occupation, and vitamin D levels showed that HBsAg(+) male had significantly lower BMD of the femur neck (0.810 ± 0.010 vs. 0.831 ± 0.002 g/cm(2), p = 0.032) and lumbar spine (0.953 ± 0.011 vs. 0.974 ± 0.003 g/cm(2), p = 0.049) than HBsAg(-) male., Conclusions: HBsAg seropositivity was significantly associated with lower BMD in male. Future long-term prospective studies investigating bone turnover markers and hormones are needed to better understand the pathophysiology and clinical significance of chronic hepatitis B virus-related hepatic osteodystrophy.

Background/aims: Adefovir dipivoxil (ADV) is a nucleotide analogue that is effective against lamivudine-resistant hepatitis B virus (HBV). The aim of this study was to determine the long-term clinical outcomes after ADV rescue therapy in decompensated patients infected with lamivudine-resistant HBV., Methods: In total, 128 patients with a decompensated state and lamivudine-resistant HBV were treated with ADV at a dosage of 10 mg/day for a median of 33 months in this multicenter cohort study., Results: Following ADV treatment, 86 (72.3%) of 119 patients experienced a decrease in Child-Pugh score of at least 2 points, and the overall end-stage liver disease score decreased from 16±5 to 14±10 (mean ± SD, P<0.001) during the follow-up period. With ADV treatment, 67 patients (56.3%) had undetectable serum HBV DNA (detection limit, 0.5 pg/mL). Virologic breakthrough occurred in 38 patients (36.1%) and 9 patients had a suboptimal ADV response. The overall survival rate was 89.9% (107/119), and a suboptimal response to ADV treatment was associated with both no improvement in Child-Pugh score (≥2 points; P=0.001) and high mortality following ADV rescue therapy (P=0.012)., Conclusions: Three years of ADV treatment was effective and safe in decompensated patients with lamivudine-resistant HBV.

The virologic determinants of progressive liver disease associated with hepatitis B virus (HBV) remain unclear. Previous investigations have associated HBV disease with specific mutations but this association may be confounded by HBV genotype, HLA haplotype of the infected individual or both. The association between non-synonymous mutations located within putative cytotoxic T-lymphocyte directed epitopes (CDE) of the HBV core region and disease states was investigated. Subjects infected with HBV were enrolled from a clinical cohort in Seoul, Korea, and HBV core gene sequences were analyzed for mutational patterns inside and outside of CDE with respect to subject demographics and HBV-related disease states. No specific mutation or pattern of mutations were associated with progressive disease states; however, individuals with cirrhosis and hepatocellular carcinoma had greater numbers of non-synonymous mutations within CDE when compared to those with chronic HBV infection who were HBeAg positive (P = 0.007 and 0.026, respectively). In conclusion, this study demonstrates that HBV disease progression is associated with viral escape mutations that are a marker of CTL activity. These data suggest that the number of non-synonymous mutations in the HBV core region may predict HBV disease progression better than any single mutation or pattern of mutations., (Copyright © 2011 Wiley Periodicals, Inc.)

Background: There are no convincing data supporting the routine use of pre-emptive therapy against HBV reactivation in various loco-regional therapies for hepatocellular carcinoma (HCC). This study investigated the incidence, severity and risk factors of HBV reactivation during loco-regional therapies., Methods: A total of 205 prospectively enrolled patients were classified in order of increasing intensity of loco-regional therapies: local ablation therapy (LAT; 43 patients), transarterial chemotherapy using adriamycin (TAC-ADR; 93 patients) or combined epirubicin-cisplatin (TAC-EC; 26 patients), and combined chemo-radiotherapy (TAC-EC+RT; 43 patients)., Results: During the follow-up, 62 (30.2%) patients developed HBV reactivation. Multivariate analysis identified HBV DNA levels >10⁴ copies/ml (P=0.041) and treatment option (P=0.001) to be independent predictors of HBV reactivation. There was a significant trend for increasing risk of reactivation with increasing intensity of therapy, with hazard ratios of 1.0 for LAT, 2.45 for TAC-ADR, 4.19 for TAC-EC and 10.17 for TAC-EC+RT. The severity of reactivated disease was also increased with increasing treatment intensity (P-value for trend <0.05). Only one of the patients with low-level viraemia receiving LAT alone developed reactivation, whereas a substantial number of patients with high-level viraemia eventually developed reactivation., Conclusions: High-level viraemia and high-level treatment intensity are the major risk factors for HBV reactivation during loco-regional therapy. Trends are evident for the increased risk and severity of reactivation with the aggressiveness of treatment. Pre-emptive antiviral therapy should be recommended for all patients with high-level viraemia irrespective of treatment option, or those undergoing any intensive therapy.

Background and Aim: Little is known about the role of hepatitis B virus (HBV) factors in the long-term prognosis of hepatocellular carcinoma (HCC) after resection. The objective of the present study was to identify the changing patterns of HBV levels and its effect on outcome after resection., Methods: This study recruited 188 patients with HBV-related HCC who underwent curative resection. Among the 188 patients, 115 were alive without recurrence at 12 months, and had serial measurements of viral levels., Results: The mean age was 53 years and the mean follow-up period was 48.5 months. With multivariate analysis, tumor size > 5 cm (P = 0.047), Child-Pugh class B (P = 0.017), vascular invasion (P = 0.028), and HBV DNA > 10(4) copies/mL at the time of resection (P = 0.003) were independently predictive of HCC recurrence for the entire population. For the 115 patients with serial measurements of viral levels, tumor size > 5 cm, HBV DNA > 10(4) copies/mL at resection, and the absence of sustained HBV DNA level < 10(4) copies/mL, the presence of cirrhosis, and elevated aminotransferase levels (> 40 IU/L) were marginally or significantly associated with HCC recurrence and overall survival. However, on multivariate analysis, sustained HBV DNA level < 10(4) copies/mL was the only factor for both low recurrence (P = 0.002; odds ratio [OR] 3.13; 95% confidence interval [CI] 1.55-6.35) and longer survival (P = 0.002; OR 3.76; 95% CI 1.61-8.78)., Conclusions: A high HBV replication state is among the most important predictors of adverse outcome after resection of HBV-related HCC. The sustained suppression of HBV below 10(4) copies/mL is a strong protective factor for long-term recurrence-free and overall survival., (© 2010 Journal of Gastroenterology and Hepatology Foundation and Blackwell Publishing Asia Pty Ltd.)

Background: Hepatocellular carcinoma (HCC) has a high tendency for recurrence after radical treatment. Apart from tumor and liver function parameters, little is known about the role of hepatitis B virus (HBV) factors in the recurrence of HCC. The objective of this study was to identify the potential relation between viral load and HCC recurrence in patients undergoing transarterial chemolipiodolization., Methods: This was a cohort study of 62 consecutive patients who had HBV-related HCC and achieved complete necrosis with transarterial chemolipiodolization. Risk factors, including viral load for posttreatment recurrence, were analyzed., Results: Overall, 32 of 62 patients (51.6%) developed a recurrence during the study period (7.2-37.5 months). Multivariate analysis established Child-Pugh Class B (P = .014), multiple tumors (P = .013), and high viral load (HBV DNA levels >10(5) copies/mL) at complete necrosis (P = .001) as independent risk factors for recurrence. On both univariate and multivariate analyses, high viral load at the time of complete necrosis was identified as the strongest factor for recurrence; moreover, its statistically significant effects still were observed even when conducting the analyses separately for both local recurrence (P = .018) and distant recurrence (P = .009)., Conclusions: Among individuals who underwent transarterial chemolipiodolization, high HBV viral load at complete necrosis was among the most important risk factors for posttreatment recurrence, irrespective of the locational pattern of recurrence. The current findings underscored the need for future work that tests the applicability of antiviral therapy to reduce the risk of HCC recurrence in this setting.

Background and Aims: The topographical distribution of hepatitis B core antigen (HBcAg) is related to the pathogenesis of liver damage caused by hepatitis B virus (HBV) infection. beta-catenin plays an important role in both intracellular adhesion and Wnt signaling transduction pathways. This study investigated the intrahepatic expression of HBcAg and beta-catenin in chronic HBV infection, and correlated the results with the degree of liver damage and viral replication., Method: Liver sections from 73 patients with chronic HBV infection were examined immunohistochemically for HBcAg and beta-catenin., Results: The distribution of HBcAg could be classified into four types: only nucleus (C-1), both nucleus and cytoplasm (C-2), only cytoplasm (C-3) and all negative for nucleus and cytoplasm (C-4). Significant differences in serum aminotransferase level, HBV DNA and necroinflammatory score were observed among the different distribution types, and as the distribution of HBcAg changed from C-1 to C-4, fibrosis stage and hepatitis B e antigen (HBeAg) negative/anti-HBe positive rate increased concurrently. The distribution of beta-catenin could be classified into two types: only membrane (B-1) and membrane with nucleus or cytoplasm (B-2). B-2 showed higher serum aminotransferase level and necroinflammatory score than B-1. Between B-1 and B-2, there was no significant difference in serum HBV DNA level or fibrosis stage., Conclusions: In chronic HBV infection, HBcAg distribution may change from C-1 to C-4 gradually, and in correlation with serum aminotransferase, and HBV DNA and HBeAg negative/anti-HBe positive rate. Nuclear or cytoplasmic distribution of beta-catenin, compared with exclusive membranous distribution of beta-catenin, is related to active hepatitis, but not viral replication.

Mannose-binding lectin (MBL) plays an important role in immune defense. This study was undertaken to investigate the association between hepatitis B virus infection and polymorphisms of MBL gene. We assessed the single nucleotide polymorphism at codon 54 in exon 1 of MBL in patients with hepatitis B virus infection and HBsAg negative controls in Korean population. A total of 498 enrolled subjects was classified into four groups. Group 1; Clearance, Group 2; Inactive healthy carrier, Group 3; Chronic hepatitis, Group 4; Liver cirrhosis. MBL gene polymorphisms at codon 54 led to three genotypes (G/G, G/A, A/A). When we divided subjects into clearance group (group 1) and persistence group (group 2-4), G/G genotype and A-allele carrier were observed in 55.6% and 44.4% in clearance group, 64.8% and 35.2% in persistence group (p=0.081), respectively. When hepatitis B virus persistent cases were divided into inactive healthy carrier (group 2) and disease progression group (group 3 and 4), MBL gene polymorphisms at codon 54 were not related to disease progression (p=0.166). MBL gene polymorphism at codon 54 was not associated with the clearance of hepatitis B virus infection nor progression of disease in chronic hepatitis B virus infection.

Background/aims: Lamivudine use in patients with decompensated cirrhosis B has been reported to improve the hepatic function and often delay the need for liver transplantation. In the present study, we evaluated the efficacy and safety of long-term lamivudine therapy in patients with decompensated cirrhosis by comparative study using a matched, untreated cohort., Methods: 41 patients with decompensated cirrhosis B were included for this study (31 male and 10 female; mean age, 50 years; mean observation period, 18 months). They were divided into two groups: a lamivudine treatment group and an untreated control group. 21 patients in the treatment group were treated with lamivudine 75 or 150 mg daily for at least 12 months. Biochemical and serologic markers were evaluated at two to three-month intervals for all patients. Clinical improvement was defined by a decrease in the Child-Pugh score of at least 2 points., Results: During the observation period, 62% (13/21) was responders, 33% (7/21) was breakthrough, and 5% (1/21) was non-responder in the treated group. The mean Child-Pugh score was significantly improved from 8.6 to 6.0 in the treatment group, but aggravated from 8.7 to 10.0 in the control group during the follow-up. The HBeAg seroconversion rate was 31% in the treatment group (5/16) and none in the control group (0/14). Clinical improvement was observed in fifteen of 21 in the treatment group (71%) and only one of 20 in the control group (5%). According to the treatment responses, clinical improvement was observed in ten of 13 responders (77%), four of 7 breakthrough (57%), and one non-responder., Conclusions: The long-term administration of lamivudine for patients with decompensated cirrhosis B is effective and safe, although breakthrough and non-response occurred in some patients.

Persistent hepatitis B virus (HBV) infection often leads to the development of chronic hepatitis, cirrhosis and hepatocellular carcinoma. There is a need to develop new antiviral approaches for the treatment of this disease. We have explored various nucleic acid-based strategies designed to inhibit HBV replication including: the use of antisense RNA and DNA constructs, DNA-based immunization techniques to stimulate broad-based cellular immune responses with particular emphasis on the generation of cytotoxic lymphocyte (CTL) activity to viral structural proteins, hammerhead ribozymes to cleave HBV pregenomic RNA in vitro and dominant negative HBV core mutant proteins as inhibitors of nucleocapsid formation within cells. In order to optimize these antiviral effects, various novel expression vectors have been developed to deliver such DNA constructs to cells. For example, adenoviral vectors carrying genes that encode for dominant negative proteins have been employed to transfect hepatocytes in vitro and in vivo. In addition, plasmid vectors have been produced to promote expression of HBV structural genes following injection into muscle cells as a means to stimulate the host's cellular and humoral immune response in the context of histocompatibility antigen (HLA) class I and II antigen presentation. These experimental approaches may have important implications for the generation of efficient antiviral effects during chronic HBV infection.