Chronic hepatitis B: past, present, and future

Entecavir resistance mutations rtL180M/T184L/M204V combined with rtA200V lead to tenofovir resistance

BACKGROUND

Tenofovir disoproxil fumarate (TDF) imposes a high genetic barrier to drug resistance and potently inhibits replication of multidrug-resistant hepatitis B virus. Few clinical cases with confirmed TDF-resistance have been reported to date.

METHODS AND RESULTS

Here, we report viral rebound in a patient with chronic hepatitis B who underwent TDF monotherapy and harboured a quadruple mutant consisting of classic entecavir (ETV)-resistance mutations (rtL180M/T184L/M204V) together with an rtA200V mutation in the reverse transcriptase gene. Sequencing analysis revealed that this quadruple mutant emerged as a major viral population. In vitro phenotyping demonstrated that the rtL180M/T184L/A200V/M204V mutant had moderate resistance to TDF treatment, with a 4.52-fold higher half maximal effective concentration than that of wild-type virus. Importantly, this patient with TDF resistance achieved virological suppression after TDF/ETV combination rescue therapy.

CONCLUSION

An rtL180M/T184L/A200V/M204V mutant with moderate resistance to TDF monotherapy was selected during sequential nucleoside analogue (NA) treatment in a stepwise manner. ETV/TDF combination therapy effectively suppressed replication of this TDF-resistant mutant. Our studies provide novel insights into the treatment of NA-naïve patients as well as patients with TDF resistance.

Efficient delivery of HBV NLS siRNAs into HepG2.2.15 cells for HBV inhibition through novel recombinant preS1‑tP proteins

Hepatitis B virus (HBV) infection and related liver complications remain severe public health problems worldwide. Previous investigations have shown that small interfering (si)RNAs can offer an effective strategy for the treatment of chronic hepatitis B. The present study aimed to develop a novel siRNA‑delivering system of therapeutic HBV nuclear localization sequence (NLS) siRNAs using the recombinant preS1‑truncated protamine (tP) proteins. The preS1 region of the LHB was used in place of scFv to construct the recombinant preS1‑tP proteins, which were applied to deliver siRNAs targeting the HBV NLS to inhibit HBV replication and infection in HepG2.2.15 cells overexpressing sodium taurocholate cotransporting polypeptide (NTCP). The results revealed that HepG2.2.15 cells with stable NTCP expression (HepG2.2.15‑NTCP cells) transfected with the recombinant lentivirus showed increased expression of NTCP genes. The HBV NLS siRNAs significantly suppressed HBV mRNA content and levels of HBsAg and HBeAg in the HepG2.2.15‑NTCP cells. Recombinant preS1‑tP proteins tagged with His and glutathione S‑transferase were found to enter into HepG2.2.15‑NTCP cells and bind with DNA. The HBV NLS siRNAs were delivered into HepG2.2.15‑NTCP cells by recombinant preS1‑tP proteins, which resulted in decreased expression of HBV mRNA, HBsAg and HBeAg, HBV DNA and covalently closed circular DNA in the HepG2.2.15‑NTCP cells. Therefore, the recombinant preS1‑tP proteins successfully delivered NLS siRNAs into HepG2.2.15 cells and repressed HBV infection and replication.

Performance verification and comparison of TianLong automatic hypersensitive hepatitis B virus DNA quantification system with Roche CAP/CTM system

AIM

To investigate and compare the analytical and clinical performance of TianLong automatic hypersensitive hepatitis B virus (HBV) DNA quantification system and Roche CAP/CTM system.

METHODS

Two hundred blood samples for HBV DNA testing, HBV-DNA negative samples and high-titer HBV-DNA mixture samples were collected and prepared. National standard materials for serum HBV and a worldwide HBV DNA panel were employed for performance verification. The analytical performance, such as limit of detection, limit of quantification, accuracy, precision, reproducibility, linearity, genotype coverage and cross-contamination, was determined using the TianLong automatic hypersensitive HBV DNA quantification system (TL system). Correlation and Bland-Altman plot analyses were carried out to compare the clinical performance of the TL system assay and the CAP/CTM system.

RESULTS

The detection limit of the TL system was 10 IU/mL, and its limit of quantification was 30 IU/mL. The differences between the expected and tested concentrations of the national standards were less than ± 0.4 Log₁₀ IU/mL, which showed high accuracy of the system. Results of the precision, reproducibility and linearity tests showed that the multiple test coefficient of variation (CV) of the same sample was less than 5% for 10²-10⁶ IU/mL; and for 30-10⁸ IU/mL, the linear correlation coefficient r² = 0.99. The TL system detected HBV DNA (A-H) genotypes and there was no cross-contamination during the “checkerboard” test. When compared with the CAP/CTM assay, the two assays showed 100% consistency in both negative and positive sample results (15 negative samples and 185 positive samples). No statistical differences between the two assays in the HBV DNA quantification values were observed (P > 0.05). Correlation analysis indicated a significant correlation between the two assays, r² = 0.9774. The Bland-Altman plot analysis showed that 98.9% of the positive data were within the 95% acceptable range, and the maximum difference was -0.49.

CONCLUSION

The TL system has good analytical performance, and exhibits good agreement with the CAP/CTM system in clinical performance.

Provider, Patient, and Practice Factors Shape Hepatitis B Prevention and Management by Primary Care Providers

GOALS

To evaluate provider knowledge, attitudes and barriers to hepatitis B virus (HBV) care and management practices across diverse primary care settings.

BACKGROUND

Factors influencing adherence to recommended HBV screening and management guidelines are poorly defined.

MATERIALS AND METHODS

Providers across various health care settings in San Francisco were surveyed. Multivariate analyses were used to identify factors associated with recommended HBV screening, vaccination, and disease monitoring.

RESULTS

Of 277 (41.3%) responding providers, 42% reported performing HBV screening in >50% of at-risk patients, and 49%, HBV vaccination in >50% of eligible patients. Most reported appropriate monitoring of a majority of HBV-infected patients with alanine aminotransferase (79%) and HBV viral load (67%) every 6 to 12 months, but performed any hepatocellular carcinoma screening in 49%. Provider factors significantly associated with HBV screening were speaking an Asian language [odds ratio (OR), 3.27], offering HBV treatment (OR, 3.00), having >25% of Asian patients in practice (OR, 2.10), practicing in safety net settings (OR, 7.51) and having higher barrier score (OR, 0.74). Appropriate HBV monitoring was associated with provider speaking an Asian language (OR, 3.43) and provider age (OR, 0.68/decade). Hepatocellular carcinoma screening was associated with having >25% of patients speaking English as a second language (OR, 4.26) and practicing in safety net settings (OR, 0.14).

CONCLUSIONS

Rates of adherence to HBV guidelines were suboptimal irrespective of practice setting and were influenced by certain provider, patient and practice factors. This study reinforces the importance of engaging primary care providers in development, dissemination, and implementation of evidence-based HBV practice guidelines.

Gender disparity in chronic hepatitis B: Mechanisms of sex hormones

Hepatitis B virus (HBV) is a common human pathogen transmitted worldwide, and its chronic infection is a well-known risk factor for hepatocellular carcinoma (HCC). The sex disparity of HBV-related liver diseases has been noticed for a long time, which could be attributed to sex hormone effects, other than gender behaviors or environmental impact. This difference is experimentally confirmed in HBV transgenic mice, as well as in immunocompetent mice receiving hydrodynamic delivery of HBV. Androgen and estrogen pathways were identified to play opposite regulations of HBV transcription by targeting viral enhancer I at molecular level. In addition to the direct effects on HBV life cycle, sex hormones may be also involved in the immune response to HBV infection and the progression of associated liver diseases, although the detailed mechanisms are still unclear. Besides, several unaddressed issues such as HBV entry, microRNA profiles, viral integration, and adaptability in which androgen and estrogen axes might be involved are warranted to be delineated. The comprehensive understanding of the sex disparity in HBV virology and pathogenesis will be helpful to provide newly biomarkers for clinical diagnosis and develop novel drugs to manage HBV-related HCC patients.

Induced immunity against hepatitis B virus

Prevention of hepatitis B virus (HBV) infection with its consequent development of HBV chronic liver disease and hepatocellular carcinoma is a global mandatory goal. Fortunately, safe and effective HBV vaccines are currently available. Universal hepatitis B surface antigen HBV vaccination coverage is almost done. Growing knowledge based upon monitoring and surveillance of HBV vaccination programs has accumulated and the policy of booster vaccination has been evaluated. This review article provides an overview of the natural history of HBV infection, immune responses and the future of HBV infection. It also summarizes the updated sources, types and uses of HBV vaccines, whether in the preclinical phase or in the post-field vaccination.

Hepatitis B and C status among health care workers in the five main hospitals in eastern Libya

The aim of the present study was to determine the frequency of hepatitis B and C transmission to health care workers (HCWs) in five major hospitals in eastern Libya and to analyze how the risk of these infections are affected by the type of occupation, hospital work place and working period. From July 2008 to June 2009, 601 HCWs (mean age: 32.90 ± 8.85 years) were tested for HBV and HCV markers using ELISA techniques. Polymerase chain reaction (PCR) was performed on all positive samples of HBsAg and Anti-HCV antibody to determine the level of HBV-DNA and HCV-RNA viremia, respectively. The overall frequency of HBsAg positivity was 1.8%. Anti-HBc, HBeAg and Anti-HBe antibodies were found in 8.5%, 0.7% and 8.0% of samples, respectively. The HBV-DNA level was positive in 55% of all HBsAg-positive samples. Approximately half of the HCWs (51.4%) were Anti-HBs antibody positive. The overall positivity rate of Anti-HCV antibodies was 2.0%, and HCV-RNA was positive in 33.3% of these samples. Overall, 52% of HCWs reported receiving full vaccination doses (three doses) against HBV infection. Among them, anti-HBs positivity was approximately 98.0%. 3.9% of those who never received any HBV vaccination dose were HBsAg positive, compared to 1.3% HBsAg positive in those HCWs who had received one or two doses of hepatitis B vaccine (p=0.01 for all comparisons). Nurses and nurse-aides had the highest rates of both HBsAg and Anti-HCV among the studied HCWs (HBsAg: 2.1% and 3.2%; Anti-HCV: 3.2% and 4.9%, respectively). It is noteworthy that doctors also had a relatively high prevalence rate of Anti-HCV (2.2%). Obstetric wards, isolation room, dialysis units and dentist work places had higher frequencies of HBV. HCV was found to be higher in the medical and surgical wards (the prevalence varied between 3% and 5.6%). There was no significant difference between HBsAg status and the work period of HCWs. In conclusion, universal precautions should be applied for the care of all patients by all HCWs. Further, HBV vaccines should be more readily available for Libyan HCWs by reinforcing current vaccination programs.

The natural course of chronic hepatitis B virus infection and its management

Chronic infection with the hepatitis B virus (HBV) runs a long natural course during which underlying changes in liver histology can progress to cirrhosis and hepatic decompensation, as well as to hepatocellular carcinoma. Therapeutic intervention is currently aiming at suppression of HBV replication by applying a number of pharmacological agents. For an optimum use of available therapies, good knowledge of the natural course of chronic infection, as well as of the role played by several viral, host, and environmental factors, is mandatory. The larger part of this chapter deals with how to treat the various subsets of patients with chronic hepatitis B (CHB), using mainly three first-line drugs: pegylated interferon-α2a, entecavir, and tenofovir, administered either in finite courses or indefinitely. The frequency of virological, serological, biochemical, and histological responses in the various subsets of patients, both during and after stopping treatment, is reviewed. It is stressed that the application of the highly potent antivirals entecavir and tenofovir, with acceptable safety records and with a high barrier to HBV resistance, represents major progress in the treatment of CHB. Despite the hitherto important developments in the treatment of viral hepatitis B, clinical cure of chronic HBV infection with HBsAg loss is achievable only in a few treated patients while eradication of HBV infection appears unrealistic. Development of new pharmacological agents acting at multiple targets of the replicative cycle of HBV may achieve higher efficacy and even cure of CHB.

Influence of age and HBeAg status on the correlation between HBV DNA and hepatic inflammation and fibrosis in chronic hepatitis B patients

AIMS

The purpose of this study was to examine the correlation between serum HBV DNA level and the severity of hepatic inflammation and fibrosis in patients with chronic hepatitis B.

METHODS

Liver function, serological markers of HBV and serum HBV DNA quantification were assayed in 215 CHB patients who also underwent liver biopsy. Liver pathology was regarded as the evaluation criteria to evaluate the correlation between serum HBV DNA level and the severity of liver inflammation and fibrosis.

RESULTS

Of the 215 patients, 136 were HBeAg-positive and 79 were HBeAg-negative; 134 patients had mild hepatic inflammation and fibrosis and 81 had significant hepatic inflammation and fibrosis in pathological diagnosis. We found that positive correlation between the severity of hepatic inflammation and fibrosis and serum HBV DNA level was only present in HBeAg-negative patients but not HBeAg-positive patients (P < 0.001). Patients' age was a key factor influencing the correlation between serum HBV DNA level and the severity of hepatic inflammation and fibrosis. the cutoff values to predict the severity of hepatic inflammation and fibrosis were 33.5 and 36 years, respectively. Using 35 years as the cutoff value, positive correlation between serum HBV DNA level and hepatic inflammation and fibrosis was observed in both HBeAg-positive and HBeAg-negative patients aged ≥ 35 years (P < 0.05), however no correlation was observed in HBeAg-positive patients aged <35 years.

CONCLUSIONS

There was positive correlation between serum HBV DNA level and hepatic inflammation and fibrosis in both HBeAg-positive and HBeAg-negative patients' aged ≥ 35 years, but in patients aged <35 years, positive correlation was only observed in HBeAg-negative patients.

Differences in metabolites of different tongue coatings in patients with chronic hepatitis B

Tongue coating is one of the important foundations of tongue diagnosis in traditional Chinese medicine (TCM) and plays an important role in reflecting the occurrence, development, and prognosis of the disease. However, its material basis is still poorly understood. In this study, a urinary metabonomic method based on gas chromatography coupled to mass spectrometry (GC/MS) was developed. The distinct clustering in metabolic profile was observed from Group A (thick yellow coating in patients with chronic hepatitis B), Group B (thick white coating in patients with chronic hepatitis B), and Group C (thin white coating with healthy humans) using orthogonal projections to latent structures (OPLS). Based on the variable of importance in the project (VIP) values, some significantly changed metabolites have been identified. These changes were related to the disturbance in energy metabolism, amino acid metabolism, nucleotide metabolism, and gut microflora, which were helpful to understand the material basis leading to the formation of tongue coating. This study demonstrated that tongue coating may have an objective material basis.

The immunopathogenetic role of autoantibodies in canine autoimmune hepatitis: lessons to learn from human autoimmune hepatitis

Autoimmune hepatitis (AIH) is not a disease entity restricted to man, but it can be found in other animals including canines. An increasing number of studies have focused on the immunopathogenesis of human autoimmune hepatitis (hAIH), but little is known of what triggers canine autoimmune hepatitis (cAIH). Several drugs, toxins, microbial and viral agents are able to induce autoantibodies and indeed immune-mediated chronic canine hepatitis with immunological and serological features similar of those seen in the human disease. We discuss the features of cAIH paying attention to the autoantibody profile of the disease in comparison to that seen in hAIH. We also discuss the immunomodulatory role of specific molecular signaling pathways such as those mediated by tumor growth factor and p38 mitogen-activated kinase in the induction of AIH, and the potential of these molecules to act as targets of specialized immunotherapeutic interventions. Review of the literature indicates that we have more to learn for the delineation of autoantibody profile and the antigen-specific immunoregulatory mechanisms involved in the pathogenesis of cAIH from the human disease, rather than the other way around.

Comparison of three Roche hepatitis B virus viral load assay formats

Two FDA-approved (in vitro diagnostic [IVD]) hepatitis B virus (HBV) viral load assays, the manual Cobas TaqMan HBV Test for use with the High Pure System (HP) and the automated Cobas AmpliPrep/Cobas TaqMan HBV Test v2.0 (CAP/CTM), were compared to a modified (not FDA-approved) version of the HP assay by automating the DNA extraction using the Total Nucleic Acid Isolation (TNAI) kit on the Cobas AmpliPrep. On average, CAP/CTM measurements were 0.08 log IU/ml higher than HP results (n = 206), and TNAI results were 0.17 log IU/ml higher than HP results (n = 166). The limit of detection (LOD), as determined by probit analysis using dilutions of the 2nd HBV international standard, was 10.2 IU/ml for CAP/CTM. The data sets for HP and TNAI were insufficient for probit analysis; however, there was 100% detection at ≥ 5 or ≥ 10 IU/ml for TNAI and HP, respectively. Linearity was demonstrated between 60 and 2,000,000 IU/ml, with slopes between 0.95 and 0.99 and R(2) values of >0.99 for all assays. Total precision (log percent coefficient of variance [CV]) was between 0.8% and 2.1% at 4.3 log IU/ml and between 1.4% and 4.9% at 2.3 log IU/ml. Correlation of samples, reproducibility, linearity, and LOD were acceptable and similar in all assays. The CAP/CTM assay and, to a lesser extent, the TNAI assay reduced hands-on time due to automation. There were no instances of contamination detected in negative samples during the course of the study, despite testing several samples up to 9.6 log IU/ml. The incidence of false-positive negative controls in HP and CAP/CTM clinical testing was <0.5% over 6 to 7 months of testing.

Serum angiotensin-converting enzyme level as a marker of fibrosis in patients with chronic hepatitis B

BACKGROUND

and aims: Hepatitis B virus (HBV) infection is a public health problem and affects nearly 350 million people worldwide. The present study was conducted in order to investigate the role of circulating angiotensin-converting enzyme (ACE) in the context of renin-angiotensin-aldosterone in newly diagnosed chronic hepatitis B infection. Moreover the association between liver fibrosis and serum ACE levels was also investigated.

MATERIALS AND METHODS

The study was performed on 50 chronic hepatitis B (CHB) patients (24 males, 26 females; median age 39.4 years, range 18-63) and 20 healthy controls. The clinical features of CHB patients including demographics, laboratory and liver biopsy findings were summarized. Serum ACE levels were measured by using commercially available kits.

RESULTS

Serum median ACE levels were 48.4 (14-83) U/L and 26.2 (12-48) U/L for the CHB patients and controls, respectively. Serum ACE levels were significantly higher in patients with CHB compared with the control group (p<0.001). Twenty-two patients (44%) had advanced liver fibrosis (Ishak score >2) and 28 patients (56%) had mild liver fibrosis (Ishak score ≤ 2). Mean serum levels of ACE were significantly higher among patients with advanced fibrosis as compared with those without advanced fibrosis (60.3±14.2 U/L vs. 39.0±10.5 U/L, p<0.001). Receiver operating characteristic (ROC) curve analysis suggested that the optimum ACE level cut-off point for advanced fibrosis was 52.5 U/L (sensitivity: 81.8%, specificity: 82.1%, PPV 78.3%, NPV 85.2%, accuracy 82%, AUC: 0.890).

CONCLUSIONS

Our study showed that elevated circulating ACE levels are commonly observed in CHB patients. This finding was more prominent in patients with advanced fibrosis in liver. When evaluating a patient along with other parameters, the inclusion of ACE levels in the evaluation of CHB patients may grant additional prognostic information.

Hepatitis B prevention, diagnosis, treatment and care: a review

Hepatitis B virus (HBV) infection is a major cause of morbidity and mortality worldwide. Chronic hepatitis B (CHB) infection is associated with an increased risk of cirrhosis, hepatic decompensation and hepatocellular carcinoma (HCC). The likelihood of developing CHB is related to the age at which infection is acquired; the risk being lowest in adults and >90% in neonates whose mothers are hepatitis B e antigen positive. Treatment of CHB infection aims to clear HBV DNA and prevent the development of complications. There are currently seven drugs available for the treatment of CHB: five nucleos(t)ide analogues and two interferon-based therapies. Long-term treatment is often required, and the decision to treat is based on clinical assessment including the phase of CHB infection and the presence and extent of liver damage. A safe and effective HBV vaccine has been available since the early 1980s. Vaccination plays a central role in HBV prevention strategies worldwide, and a decline in the incidence and prevalence of HBV infection following the introduction of universal HBV vaccination programmes has been observed in many countries including the USA and parts of South East Asia and Europe. Post-exposure prophylaxis (PEP) with HBV vaccine +/- hepatitis B immunoglobulin is highly effective in preventing mother to child transmission and in preventing transmission following sharps injuries, sexual contact and other exposures to infected blood and body fluids. Transmission of HBV in the health care setting has become an increasingly rare event in developed nations. However, it remains a significant risk in developing countries reflecting the higher prevalence of CHB, limited access to HBV vaccination and PEP and a lack of adherence to standard infection control precautions.

Unsuccessful therapy with adefovir and entecavir-tenofovir in a patient with chronic hepatitis B infection with previous resistance to lamivudine: a fourteen-year evolution of hepatitis B virus mutations

Background

Complex mutants can be selected under sequential selective pressure by HBV therapy. To determine hepatitis B virus genomic evolution during antiviral therapy we characterized the HBV quasi-species in a patient who did no respond to therapy following lamivudine breakthrough for a period of 14 years.

Case Presentation

The polymerase and precore/core genes were amplified and sequenced at determined intervals in a period of 14 years. HBV viral load and HBeAg/Anti-HBe serological profiles as well as amino transferase levels were also measured. A mixture of lamivudine-resistant genotype A2 HBV strains harboring the rtM204V mutation coexisted in the patient following viral breakthrough to lamivudine. The L180M+M204V dominant mutant displayed strong lamivudine-resistance. As therapy was changed to adefovir, then to entecavir, and finally to entecavir-tenofovir the viral load showed fluctuations but lamivudine-resistant strains continued to be selected, with minor contributions to the HBV quasi-species composition of additional resistance-associated mutations. At the end of the 14-year follow up period, high viral loads were predominant, with viral strains harboring the lamivudine-resistance signature rtL180M+M204V. The precore/core frame A1762T and G1764A double mutation was detected before treatment and remaining in this condition during the entire follow-up. Specific entecavir and tenofovir primary resistance-associated mutations were not detected at any time. Plasma concentrations of tenofovir indicated adequate metabolism of the drug.

Conclusions

We report the selection of HBV mutants carrying well-defined primary resistance mutations that escaped lamivudine in a fourteen-year follow-up period. With the exception of tenofovir resistance mutations, subsequent unselected primary resistance mutations were detected as minor populations into the HBV quasispecies composition during adefovir or entecavir monotherapies. Although tenofovir is considered an appropriate therapeutic alternative for the treatment of entecavir-unresponsive patients, its use was not effective in the case reported here.

The Role of Antiviral Therapy for HBV-Related Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a highly prevalent and lethal cancer worldwide; despite the curative treatment for HCC, the rate of tumor recurrence after hepatectomy remains high. Tumor recurrence can occur early (<2 years) or late (>2 years) as metastases or de novo tumors. Several tumor factors were associated with HCC recurrence; high hepatitis B virus (HBV) load is the major risk factor for late recurrence of HCC after resection. Preoperative antiviral therapy improves liver function, and postoperative reduce HCC recurrence. In this paper, we focus on antiviral treatment to improve the liver function, prevent recurrence, and lengthen the overall survival for HBV-related HCC.