HBV genotypes in India: do they influence disease severity?

Hepatitis B virus genotypes in precision medicine of hepatitis B-related hepatocellular carcinoma: Where we are now

Hepatitis B virus (HBV) infection is a major player in chronic hepatitis B that may lead to the development of hepatocellular carcinoma (HCC). HBV genetics are diverse where it is classified into at least 9 genotypes (A to I) and 1 putative genotype (J), each with specific geographical distribution and possible different clinical outcomes in the patient. This diversity may be associated with the precision medicine for HBV-related HCC and the success of therapeutical approaches against HCC, related to different pathogenicity of the virus and host response. This Editorial discusses recent updates on whether the classification of HBV genetic diversity is still valid in terms of viral oncogenicity to the HCC and its precision medicine, in addition to the recent advances in cellular and molecular biology technologies.

Hepatitis B virus genotypes influence clinical outcomes: A review

Hepatitis B virus (HBV) is a hepatotropic virus that affects approximately 296 million people worldwide. A crucial step to HBV replication is the transcription of its infectious DNA from its viral RNA intermediate. The production of the RNA intermediate hinges on reverse transcription, and therefore the lack of proofreading in that process commonly yields mutants and has led to nine well-described genotypes (A-I) and over 30 known sub-genotypes of the virus. The influence of genotype on HBV infection outcomes, which include fibrosis progression, cirrhosis, and hepatocellular carcinoma (HCC), remain uncertain. This review aims to analyze the influence of HBV genotype on the risk of development of these outcomes. The response to current and future HBV therapies is considered. Further study of larger and more diverse samples will hopefully resolve outstanding uncertainties.

Current Challenges and Future Perspectives of Diagnosis of Hepatitis B Virus

It is estimated that approximately 260 million people worldwide are infected with the hepatitis B virus (HBV), which is one of the leading causes of liver disease and liver cancer throughout the world. Compared with developed countries, low-income and middle-income countries have limited access to resources and advanced technologies that require highly specialized staff for HBV diagnosis. In spite of the heavy burden caused by hepatitis B virus, 90% of people are still undiagnosed. The World Health Organization (WHO) goal of eliminating hepatitis B by 2030 seems very difficult to achieve due to the existing diagnostic infrastructure in low-resource regions. The majority of diagnostic laboratories still use hepatitis B surface antigen (HBsAg)-based tests. WHO's elimination plan is at risk of derailment due to phases like the window period, immune control, and occult HBV infection (OBI) not being detected by standard tests. Here, in this article, we are focusing on various diagnostic platforms for the better diagnosis of HBV. The aim of the elimination of HBV can only be achieved by detecting all phases of HBV infection, which can be executed by a combined approach of using new marker assays along with advanced pretesting and testing methods.

Critical Updates on Chronic Hepatitis B Virus Infection in 2021

Chronic hepatitis B virus (HBV) infection is a global healthcare burden in the form of chronic liver disease, cirrhosis, liver failure and liver cancer. There is no definite cure for the virus and even though extensive vaccination programs have reduced the burden of liver disease in the future population, treatment options to eradicate the virus from the host are still lacking. In this review, we discuss in detail current updates on the structure and applied biology of the virus in the host, examine updates to current treatment and explore novel and state-of-the-art therapeutics in the pipeline for management of chronic HBV. Furthermore, we also specifically review clinical updates on HBV-related acute on chronic liver failure (ACLF). Current treatments for chronic HBV infection have seen important updates in the form of considerations for treating patients in the immune tolerant phase and some clarity on end points for treatment and decisions on finite therapy with nucleos(t)ide inhibitors. Ongoing cutting-edge research on HBV biology has helped us identify novel target areas in the life cycle of the virus for application of new therapeutics. Due to improvements in the area of genomics, the hope for therapeutic vaccines, vector-based treatments and focused management aimed at targeting host integration of the virus and thereby a total cure could become a reality in the near future. Newer clinical prognostic tools have improved our understanding of timing of specific treatment options for the catastrophic syndrome of ACLF secondary to reactivation of HBV. In this review, we discuss in detail pertinent updates regarding virus biology and novel therapeutic targets with special focus on the appraisal of prognostic scores and treatment options in HBV-related ACLF.

HBV Integration-mediated Cell Apoptosis in HepG2.2.15

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer and the second leading cause of cancer deaths in the word. Hepatitis B virus (HBV) infection plays an important role in the development of HCC. However, the mechanisms by which HBV integration affects host cells remain poorly understood. HepG2.2.15 cell line is derived from HCC cell line HepG2 with stable transfection HBV expression. In this study, HepG2.2.15 cells showed decreased proliferation, G1 cell cycle arrest and increased apoptosis, when compared to HepG2 cells. HBV capture sequencing was conducted in both genome and transcriptome level, followed by RNA expression sequencing in HepG2.2.15. Here, CAMSAP2/CCDC12/DPP7/OR4F3 were found to be targets for HBV integration in both genome and transcriptome level, accompanied by alteration in their expression when compared to HepG2. Among these genes, DPP7 was the only one gene with HBV integration into its exon, meanwhile DPP7 expression level was also downregulated in HepG2.2.15 as compared to HepG2. Furthermore, DPP7 knockdown resulted in increased apoptosis through upregulation of the Bax/Bcl2 ratio in HepG2 cells. Our results suggest that HBV integration of DPP7 was involved in cell apoptosis.

Epidemiology of Hepatitis B Virus Infection in Bangladesh: Prevalence among General Population, Risk Groups and Genotype Distribution

Despite a considerable body of published research on hepatitis B in Bangladesh, researchers continue to lament the lack of reliable information about hepatitis B virus (HBV) infection epidemiology. The present review aims to provide a comprehensive survey of the literature with particular focus on a number of epidemiological questions, as well as a commentary on the trends of hepatitis B research as it has taken place in Bangladesh. The key themes to emerge from this review are: first, beyond noting a declining trend, it is difficult to provide conclusive estimates about HBV prevalence in the general population of Bangladesh. The majority of the studies, even the ones conducted on apparently healthy populations, fail to be adequately representative for the reasons explored in the article. Secondly, HBV infection in Bangladesh is sharply stratified across sociodemographic lines, which speaks to the role of awareness and risk exposure in HBV prevalence. Third, more research on occult infection rates is required to estimate the extent of risk posed by the current blood donation screening program, which relies exclusively on hepatitis B surface antigen as a biomarker. The same considerations apply for the comparative importance of vertical versus horizontal transmission and prevalence among particular risk groups like healthcare workers with high occupational exposure. Finally, while recent studies do allow us, albeit with some ambiguity, to draw conclusions about distribution of HBV genotypes in Bangladesh, there needs to be an added emphasis on molecular epidemiology. It is hoped that the present review, the first of its kind in Bangladesh, will serve as an up-to-date summary of the course HBV epidemiology research in Bangladesh has taken thus far, as well as crucial gaps to address going forward.

Genotyping and sero-virological characterization of hepatitis B virus (HBV) in blood donors, Southern Ethiopia

Hepatitis B virus (HBV) prevalence is highest in Sub-Saharan Africa including Ethiopia. HBV genotypes have distinct geographic distributions and play a role in course of infection and treatment management. However, in Ethiopia there is paucity of information about distribution of HBV genotypes. This study was done to determine genotype, mutation and sero-virological profiles of HBV isolates in Southern Ethiopia. Cross-sectional, laboratory based study was conducted on 103HBsAg sero-positive samples from a total of 2,237 screened blood donors. HBV serological markers and biochemical assays were done. Serum viral load was measured using quantitative real-time PCR. Partial HBV S-gene was amplified with nested PCR and sequenced. Bioinformatics tools were utilized to determine genotypes, serotypes and mutations. Of 103 HBsAg reactive serum samples, 14.6% and 70.9% were sero-positive for HBeAg and HBeAb, respectively. Ninety-eight samples gave detectable viral load with a median of 3.46(2.62-4.82) log IU/ml. HBeAg sero-positive donors carried elevated levels of viral load. Eighty five isolates were successfully amplified, sequenced and genotyped into 58 (68.2%) genotype A (HBV/A) and 27 (31.8%) genotype D (HBV/D). HBV serotypes found were adw2 (74.1%), ayw2 (24.7%), and ayw3 (1.2%). In twenty-four (28.2%) samples mutations in the major hydrophilic region (MHR) were observed. Donors infected with HBV/A had higher viral load and more frequent MHR mutation than HBV/D infected donors. This study illustrated distribution of HBV genotype A and D among blood donors in southern Ethiopia. It also demonstrated occurrence HBV variants that may influence clinical aspects of HBV infection. The study contributes in narrowing the existing gap of HBV molecular study in Ethiopia.

Current Scenario of Hepatitis B and Its Treatment in India

Hepatitis B is a significant public health problem in India, yet disease awareness is very low among the general population. The disease is mostly acquired horizontally, but the role of vertical transmission should not be underestimated. In spite of the fact that the majority of cases are e negative disease, most patients present in the advanced stage and even with hepatocellular carcinoma, the leading cause of which is hepatitis B. High-risk groups (especially tribals) also harbour significant disease burden and have a high prevalence of occult infection, supporting the potential of unknowingly spreading the disease. Findings on the relation of genotypes with disease severity or drug action have been conflicting. Though recently, oral antivirals with high genetic barrier to resistance have shown good viral suppression in the long term, e and s seroconversion is poor and relapse is universal upon therapy discontinuation. As no cure is possible with the currently available therapy, the target is long-term viral suppression by prolonged administration of oral antivirals; unfortunately, this leads to poor treatment adherence, which along with the high cost of therapy results in disease progression and spread of infection. At present, therefore, emphasis should be put on health education of the general and high-risk populations, along with health care workers to increase knowledge on such preventive measures as avoiding unsafe injection practices, high-risk sex, performing unnecessary injection and blood transfusion and providing proper screening of blood products; these efforts should be combined with intensive screening and aggressive vaccination programs, especially in high-risk groups and areas of high endemicity. Vaccination strategies are still below par and logistics should be developed for wider coverage; in addition, further research should be carried out on the efficacy and mode of usage for different types of vaccine.

Hepatitis B virus genotyping in chronic hepatitis B patients in southwestern Saudi Arabia

The distribution of hepatitis B virus genotypes in Saudi Arabia is largely unknown. To the best of our knowledge there are no data available about HBV genotypes in southwestern region of the country. This study aimed to determine the epidemiologic distribution of hepatitis B virus genotypes in chronic hepatitis B patients in southwestern region, and to verify possible correlations between these genotypes and the clinical symptoms. A total of 160 patients with chronic hepatitis B infection were enrolled in this study. Sera were tested for liver function tests, hepatitis B virus markers and DNA load by standard procedures. HBV genotyping was performed by 2-tube nested PCR for determination of six genotypes (A–F). Genotype D was the most common, found in 135 (84.4%) patients, followed by A (18; 11.3%) and E (7; 4.3%). The rate of HBeAg positivity in genotype D patients was significantly lower compared with that in genotype A and E patients (p = 0.01). There was no significant association between HBV genotypes and age, gender, liver function tests, or HBV DNA load. Genotypes D and E were predominant in chronic hepatitis B patients in southwestern Saudi Arabia. Awareness of hepatitis B virus serologic and genotypic patterns might help in the formulation of management plans, predicting clinical outcomes and updating prevention strategies.

Mutation profiling of the hepatitis B virus strains circulating in North Indian population

AIMS

The aim of this study was to investigate the genomic mutations in the circulating Hepatitis B virus strains causing infection in the Indian population. Further, we wanted to analyze the biological significance of these mutations in HBV mediated disease.

METHODS

222 HBsAg positive patients were enrolled in the study. The genotype and mutation profile was determined for the infecting HBV isolate by sequencing overlapping fragments. These sequences were analyzed by using different tools and compared with previously available HBV sequence information. Mutation Frequency Index (MFI) for the Genes and Diagnosis group was also calculated.

RESULTS

HBV Genotype D was found in 55% (n = 121) of the patient group and genotype A was found in 30% (n = 66) of samples. The majority (52%) of the HBV-infected individuals in the present study were HBeAg-negative in all the age groups studied. Spontaneous drug associated mutations implicated in resistance to antiviral therapy were also identified in about quarter of our patients, which is of therapeutic concern. The MFI approach used in the study indicated that Core peptide was the most conserved region in both genotypes and Surface peptide had highest mutation frequency. Few mutations in X gene (T36A and G50R) showed high frequency of association with HCC. A rare recombinant strain of HBV genotype A and D was also identified in the patient group.

CONCLUSIONS

HBV genotype D was found out to be most prevalent. More than half of the patients studied had HBeAg negative disease. Core region was found to be most conserved. Drug Associated mutations were detected in 22% of the patient group and T36A and G50R mutations in X gene were found to be associated with HCC.

Hepatitis B virus genetic variants: biological properties and clinical implications

Hepatitis B virus (HBV) causes a chronic infection in 350 million people worldwide and greatly increases the risk of liver cirrhosis and hepatocellular carcinoma. The majority of chronic HBV carriers live in Asia. HBV can be divided into eight genotypes with unique geographic distributions. Mutations accumulate during chronic infection or in response to external pressure. Because HBV is an RNA-DNA virus the emergence of drug resistance and vaccine escape mutants has become an important clinical and public health concern. Here, we provide an overview of the molecular biology of the HBV life cycle and an evaluation of the changing role of hepatitis B e antigen (HBeAg) at different stages of infection. The impact of viral genotypes and mutations/deletions in the precore, core promoter, preS, and S gene on the establishment of chronic infection, development of fulminant hepatitis and liver cancer is discussed. Because HBV is prone to mutations, the biological properties of drug-resistant and vaccine escape mutants are also explored.

Meta-analysis: The association of hepatitis B virus genotypes and hepatocellular carcinoma

BACKGROUND

A meta-analysis on the risk of hepatocellular carcinoma (HCC) among hepatitis B virus (HBV) genotypes is warranted as the current data are conflicting.

AIM

To investigate the relative risk of HCC among the four major HBV genotypes (A-D).

METHODS

A meta-analysis was performed based on literature search from electronic databases and bibliography between 1950 and 2012. All abstracts with keywords 'hepatitis B', 'hepatocellular carcinoma' and 'genotype' were screened. Studies were included if they reported HBV genotype as an exposure and HCC as an outcome.

RESULTS

Nine hundred and eighty-eight abstracts were found through literature search, among them 43 studies were eligible for this meta-analysis. A total of 14,545 patients with an average age of 43 years were included; 71% were male patients and 17% had cirrhosis. In 33 studies, HCC was found in 1541/6060 (25%) genotype C vs. 550/4417 (12%) genotype B HBV-infected patients [odds ratio (OR) = 2.05, 95% confidence interval (CI) = 1.52-2.76, P < 0.001]. No difference in the risk of HCC was found among genotype A (71/517, 14%) vs. genotype D (170/1506, 11%) HBV-infected patients in 14 studies (OR = 0.94, 95% CI = 0.67-1.32). In 10 studies, the risk of HCC was also found higher among genotype C (498/1659, 30%) than genotype A&D (103/1403, 7%) HBV-infected patients (OR = 2.34, 95% CI = 1.63-3.34, P < 0.001). Subgenotype Ce and Cs HBV-infected patients had similar risk on HCC (OR = 1.13, 95% CI = 0.76-1.67, P = 0.54). On funnel plot analysis, there was no significant publication bias in all comparisons.

CONCLUSION

Genotype C hepatitis B virus is associated with a higher risk of hepatocellular carcinoma than other major hepatitis B virus genotypes.

Hepatitis B virus genotyping: is the time ripe for routine clinical use?

Hepatitis B is one of the major causes of end-stage liver disease and liver cancer worldwide. A number of host and viral factors influence the disease course and outcomes. One such viral factor is hepatitis B virus (HBV) genotypes. There are eight major HBV genotypes described from various geographic regions of the world. Although direct sequencing appears to be the gold standard for HBV genotyping, it is expensive and laborintensive and therefore cannot be applied for routine clinical use. The newer molecular methods including serotyping have made genotyping easier and simple to apply to large number of samples rapidly. The data collected mainly over the last decade have suggested that HBV genotypes may have a bearing over the natural course of the disease and its response to therapy. This review summarizes the available literature and highlights how genotyping could be incorporated into routine clinical practice in order to improve delivery of care to HBV-infected individuals.

Prevalence of Genotype D and Precore/Core Promoter Mutations in Hepatitis B Virus-infected Population of North India

Hepatitis B virus (HBV) isolates (21) from Punjab (North India) were studied for genotype distribution and precore/core promoter mutations. Assays of alanine aminotransaminase (ALT) and HBeAg were performed in all isolates. Genotypes were determined in all the samples by restriction fragment length polymorphism and the precore/core promoter mutations were studied by amplification and by direct sequencing of precore/core promoter region. Sixty-two percent of the isolates had higher ALT levels and 57% of the isolates were HBeAg negative. It was observed that 90% of the isolates were HBV D genotype (subgenotype D1 and D2) and 10% of the isolates were HBV A genotype (subgenotype A1). Amplification and sequencing of the precore/core promoter region showed 1762(A-T) and 1764(G-A) mutations in 29% and 19% of the isolates, respectively. 1809(C/T) mutation was observed in 71% of the isolates under study. Novel precore and core promoter mutations like 1690(A), 1695(A/T/G), 1700(A/C), 1703(c), 1850(A) and 1915(A/G) were observed in HBV-infected population of the state of Punjab (North India). Deletion and insertional mutations were also observed in some patients. (J CLIN EXP HEPATOL 2011;1:73-76).

Hepatitis B virus: from diagnosis to treatment

During the next few decades, vaccination against hepatitis B virus (HBV) will dramatically change the epidemiological profile of this worldwide infection especially when Heath Policies encourage including HBV vaccination program for the newborns. However, it is still estimated that more than 2000millions living people have met HBV. Symptomatic hepatitis with jaundice is less frequent than asymptomatic infection; however, as much as 350millions of individuals remain chronically infected by HBV. In these cases, the need for efficient antiviral therapy remains clear when a viral replication is observed to control the risk of progression and the need for liver transplantation, which represents the only end-stage treatment. Indeed, patients having chronic hepatitis B (CHB) can now be successfully treated using nucleos(t)ide analogs (NA) or pegylated interferon (PEG-IFN). Therefore, beside vaccination, prevention of the progression of the disease to cirrhosis and liver decompensation, leading to end-stage liver disease and/or to hepatocellular carcinoma, by inhibiting viral replication seems to represent the best approach to improve survival. At last but not least, co-morbidities and other viral infections, leading also to chronic liver cirrhosis or liver inflammation such as the specific satellite delta virus (HDV), human immunodeficency virus (HIV) and/or hepatitis C (HCV) virus, are able to accelerate the progression and have to be taken in account. Interestingly, in treated infection, the dogma of the irreversibility of the liver fibrosis, when the cirrhosis is constituted, is tumbling down. In this review, we will focus on the clinical, virological and therapeutic aspects of hepatitis B infection in order to expose the proposals to follow-up and treat HBV-infected patients and the prevention of drug-resistant HBV mutants that frequently arise, leading to treatment failure and progression to liver disease.

Novel method for genotyping hepatitis B virus on the basis of TaqMan real-time PCR

Chronic infection with hepatitis B virus (HBV) is an important cause of cirrhosis and cancer of the liver. HBV is currently classified into eight genotypes, A to H. Accumulated evidence shows that the genotype influences both the clinical course of infection and the response to treatment. We describe a new method for genotyping based on TaqMan real-time PCR, which identifies all HBV genotypes without post-PCR processing. In this assay, each sample is processed in four multiplex real-time PCRs, each targeting two or three genotype-specific segments of HBV. By analyzing 185 samples representing all genotypes and different proportions of genotype mixtures, we could validate high accuracy of the assay. We conclude that this new assay represents a significant advancement for both diagnostics and clinical research because it is accurate, practical, and based on a technique that is well established in many virological laboratories.