Clinical outcome and virological characteristics of hepatitis B-related acute liver failure in the United States

Hepatitis B Vaccine: Four Decades on

Hepatitis B virus is a substantial contributor to cirrhosis and hepatocellular carcinoma (HCC) globally. Vaccination is the most effective method for prevention of hepatitis B and its associated morbidity and mortality, and the only method to prevent infection with hepatitis D virus. The hepatitis B vaccine has been used worldwide for more than four decades; it is available in a single- or triple-antigen form and in combination with vaccines against other infections. Introduction of the vaccine and administration at birth led to sustained decline in mother-to-child transmission, chronic hepatitis B, and HCC, however, global birth dose coverage remains suboptimal. In this review we will discuss different hepatitis B vaccine formulations and schedules, vaccination guidelines, durability of the response, and vaccine escape mutants, as well as the clinical and economic benefits of vaccination.

Transplantation of hepatitis D virus patients: Lifelong hepatitis B immunoglobulins?

The introduction of Hepatitis B Immunoglobulins (HBIg) prophylaxis at and after liver transplantation (LT) facilitated excellent long-term survival of transplant patients with chronic hepatitis B virus (HBV) infection. Several studies suggested that only short-term (i.e. 4-8 weeks) HBIg prophylaxis after LT followed by the long-term administration of HBV polymerase inhibitors prevents HBV recurrence. In hepatitis D virus (HDV)/HBV co-infected patients, the need for long-term HBIg prophylaxis on top of HBV polymerase inhibitors is unknown. HDV requires HBV surface antigen (HBsAg) for uptake into hepatocytes to subsequently establish HDV replication. Data on HDV recurrence and its impact on outcomes after LT are limited. In this review, we evaluated the available data on post-LT recurrence of HBV and/or HDV. Overall, HBIg prophylaxis was effective, but 10-13% of patients became HBsAg positive after LT. Only a single study from Turkey reported HDV recurrence, which was not observed in other LT centres. Since all studies administered continuous HBIg prophylaxis, the post-LT recurrence rates without HBIg prophylaxis remain unknown. In a German study, the clinical course and histopathological aspects of liver injury (inflammation, fibrosis and steatosis) were similar in post-LT patients on continuous HBIg and those who stopped HBIg after a median of 72 months. Discontinuation of HBIg in stable patients after LT for HBV/HDV co-infection did not lead to impaired overall survival or a higher recurrence rate in this long-term follow-up. In summary, discontinuation of HBIg after liver transplantation for HBV/HDV liver disease seems safe, but randomized controlled studies are needed before it can be generally recommended.

Relevance of HBx for Hepatitis B Virus-Associated Pathogenesis

The hepatitis B virus (HBV) counts as a major global health problem, as it presents a significant causative factor for liver-related morbidity and mortality. The development of hepatocellular carcinomas (HCC) as a characteristic of a persistent, chronic infection could be caused, among others, by the pleiotropic function of the viral regulatory protein HBx. The latter is known to modulate an onset of cellular and viral signaling processes with emerging influence in liver pathogenesis. However, the flexible and multifunctional nature of HBx impedes the fundamental understanding of related mechanisms and the development of associated diseases, and has even led to partial controversial results in the past. Based on the cellular distribution of HBx-nuclear-, cytoplasmic- or mitochondria-associated-this review encompasses the current knowledge and previous investigations of HBx in context of cellular signaling pathways and HBV-associated pathogenesis. In addition, particular focus is set on the clinical relevance and potential novel therapeutic applications in the context of HBx.

Review on hepatitis B virus precore/core promoter mutations and their correlation with genotypes and liver disease severity

Of 350 million people worldwide are chronically infected with hepatitis B virus (HBV) and are at risk of developing cirrhosis and hepatocellular carcinoma (HCC) later in life. HBV is the most diverse DNA virus, and its genome is composed of four open reading frames: Presurface antigen/surface antigen gene (preS/S), precore/core gene (preC/C), polymerase gene (P), and the X gene (X). HBV produces quasispecies naturally or in response to antiviral agents because of the absence of proofreading activity amid reverse transcription and a high replication rate. The virus has 10 genotypes (A to J) with different geographical distributions. There are various HBV mutations in the HBV genome, including preC/C mutations, preS/S mutations, P gene mutations, and X gene mutations. The core promoter region plays a vital part in the replication, morphogenesis and pathogenesis of the virus. The precore region also plays a crucial role in viral replication. Both core promoter and precore mutations rescue the virus from host immune surveillance and result in the formation of mutated strains that may have altered pathogenicity. preC/C mutations are associated with liver disease progression. Precore mutations stop hepatitis B e antigen (HBeAg) production and basal core promoter mutations downregulate HBeAg production. Mutations in the basal core promoter are also associated with increased HBV replication and an increased incidence of advanced liver diseases such as cirrhosis and HCC. The emergence of antiviral-resistant mutations is the main reason for treatment failure. This review focuses mainly on preC/C promoter mutations and their correlation with genotypes and liver disease severity. Thorough perception and knowledge of HBV genetic variety and mutants could be vital to discover techniques for the prognosis and control of HBV infection.

Hepatitis B Virus Genotypes and Antiviral Resistance Mutations in Romanian HIV-HBV Co-Infected Patients

Background and Objectives: Romania has one of the highest prevalence of hepatitis B virus (HBV) infection in human immunodeficiency virus (HIV) patients, mostly in those parenterally infected during childhood; nevertheless, there are scarce data on the virological profile of co-infection. The objective of this study was to assess the prevalence of HBV genotypes and antiviral resistance-associated mutations (RAMs) in these co-infected patients, in order to monitor the viral factors associated with the evolution of liver disease. Materials and Methods: HBV genotypes and RAMs were detected using nested PCR and line probe assays (INNO-LiPA HBV genotyping assay, and INNO-LiPA HBV DR v2, Innogenetics). Results: Out of 117 co-infected patients, 73.5% had detectable HBV-DNA, but only 38.5% presented an HBV viral load >1000 IU/mL. HBV genotype A was present in 66.7% of the cases and was dominant in patients parenterally infected during early childhood, who experienced multiple treatment regimens, with a mean therapy length of 15.25 years, and present numerous mutations associated with lamivudine (LAM) resistance, but very rarely active liver disease. HBV genotype D was detected in 33.3% of the cases, mostly in recently diagnosed injecting drug users who are treatment naïve, but, nevertheless, present RAMs in 63.5% of the cases, suggesting transmitted drug resistance, and display more frequently advanced liver fibrosis (36.1% vs. 12.3%; p = 0.033). The most frequently encountered RAMs are M204V/I: 48.8%, L180M: 33.3%, L80V: 28.8%, and V173L: 42.2%. There are no significant differences in the distribution of RAMs in patients infected with different HBV genotypes, except for the L80V and N236T mutations, which were more frequently found in HBV genotype A infections (p = 0.032 and p = 0.004, respectively). Conclusions: HBV genotypes A and D are the only genotypes present in HIV−HBV co-infected patients from Romania, with different distributions according to the infection route, and are frequently associated with multiple RAMs, conferring extensive resistance to LAM.

Epidemiology, Genotyping, Mutational and Phylogenetic Analysis of Hepatitis B Virus Infection in North-east India

BACKGROUND/OBJECTIVE

Hepatitis B virus (HBV) infection is a major public health problem globally. Northeast India is home to indigenous tribes with different ethnicity and high rates of drug abuse and HIV infection. The study was designed to estimate the burden of HBV infection across various spectrums of liver diseases from this region. HBV genotypes and subgenotypes play a role in the chronicity of disease, response to treatment and its progression. As very limited data are available from this region, we tried to elucidate the role of HBV genotypes, HBV mutants and their phylogenetic analysis.

METHOD

We designed a prospective multicentric study, and included 7464 liver disease cases, 7432 blood donors and 650 health care workers, who were screened for HBV infection. HBV DNA positive patients were genotyped and subjected to surface protein, precore and core mutation and phylogenetic analysis.

RESULTS

The prevalence of HBV infection with respect to different types of liver diseases, blood donors and health care workers was 9.9% (1550/15,546). 49.5% (768/1550) cases were found to be HBV DNA positive. The most common genotype was found to be genotype D 74.2% (570/768), followed by genotype C 6.5% (50/768), A 4.4% (34/768) and I 0.9% (7/768).

CONCLUSION

This study highlights the high hepatitis B burden in Northeast India, reflecting lacunae in health care needs of the region. Also, the different genotype distribution and presence of mutations may translate into different rates of liver disease progression, prognosis and ultimately, clinical significance. However, further prospective cohort study from Northeast India is warranted, to elucidate the clinical significance of multiple genotypes and mutation in this unique population.

Genotype E: The neglected genotype of hepatitis B virus

Hepatitis B virus (HBV) (sub)genotypes A1, D3 and E circulate in sub-Saharan Africa, the region with one of the highest incidences of HBV-associated hepatocellular carcinoma globally. Although genotype E was identified more than 20 years ago, and is the most widespread genotype in Africa, it has not been extensively studied. The current knowledge status and gaps in its origin and evolution, natural history of infection, disease progression, response to antiviral therapy and vaccination are discussed. Genotype E is an African genotype, with unique molecular characteristics that is found mainly in Western and Central Africa and rarely outside Africa except in individuals of African descent. The low prevalence of this genotype in the African descendant populations in the New World, phylogeographic analyses, the low genetic diversity and evidence of remnants of genotype E in ancient HBV samples suggests the relatively recent re-introduction into the population. There is scarcity of information on the clinical and virological characteristics of genotype E-infected patients, disease progression and outcomes and efficacy of anti-HBV drugs. Individuals infected with genotype E have been characterised with high hepatitis B e antigen-positivity and high viral load with a lower end of treatment response to interferon-alpha. A minority of genotype E-infected participants have been included in studies in which treatment response was monitored. Of concern is that current guidelines do not consider patients infected with genotype E. Thus, there is an urgent need for further large-scale investigations into genotype E, the neglected genotype of HBV.

Infection courses, virological features and IFN-α responses of HBV genotypes in cell culture and animal models

BACKGROUND & AIMS

HBV consists of 9 major genotypes (A to I), 1 minor strain (designated J) and multiple subtypes, which may be associated with different clinical characteristics. As only cell lines expressing genotype D3 have been established, herein, we aimed to establish stable cell lines producing high-titer cell culture-generated HBV (HBVcc) of different genotypes and to explore their infectivity, virological features and responses to treatment.

METHODS

Stable cell lines producing high titers of HBV genotype A2, B2, C1, E, F1b and H were generated by transfecting plasmids containing a replication-competent 1.3x length HBV genome and an antibiotic marker into HepG2 cells that can support HBV replication. Clones with the highest levels of HBV DNA and/or HBeAg were selected and expanded for large-scale purification of HBVcc. HBVcc of different genotypes were tested in cells and a humanized chimeric mouse model.

RESULTS

HBVcc genotypes were infectious in mouse-passaged primary human hepatocytes (PXB cells) and responded differently to human interferon (IFN)-α with variable kinetics of reduction in HBV DNA, HBeAg and HBsAg. HBVcc of all genotypes were infectious in humanized chimeric mice but with variable kinetics of viremia and viral antigen production. Treatment of infected mice with human IFN-α resulted in modest and variable reductions of viremia and viral antigenemia. HBVcc passaged in humanized chimeric mice (HBVmp) infected PXB cells much more efficiently than that of the original HBVcc viral stock.

CONCLUSIONS

Herein, we generated stable cell lines producing HBV of various genotypes that are infectious in vitro and in vivo. We observe genotype-associated variations in viral antigen production, infection kinetics and responses to human IFN-α treatment in these models.

LAY SUMMARY

Stable cell lines producing high-titer cell culture-generated hepatitis B virus (HBV) of various genotypes were established. HBV genotypes showed stable infectivity in both in vitro and in vivo models, which are valuable tools for antiviral development.

Liver transplantation in acute liver failure due to Hepatitis B. Two clinical cases

Hepatitis B virus (HBV) related acute liver failure (ALF) is uncommon in our region, and there is limited HBV literature regarding the optimal management of these cases. In this article, we report two clinical cases of young men who have sex with men (MSM), both developed severe acute hepatitis caused by HBV, progressed to ALF and afterward required liver transplantation. Antiviral post-transplant treatment included entecavir without Hepatitis B Immunoglobulin (HBIG), and immunosuppression therapy with steroids, tacrolimus, and mycophenolate. Serologic follow-up showed early Hepatitis B surface Antigen (HBsAg) seroconversion, undetectable HBV viral load, and positive Anti-HBs titers. During later follow-up, Anti-HBs titers gradually fell (<10mUI/L after six months), with normal liver function. DISCUSSION: In cases of HBV-related ALF, the liver develops a robust immune response, leading to, an early undetectable viral load and seroconversion, with loss of HBsAg, and the appearance of Anti-HBs as a result of the inflammatory response. The management varies depending on whether this is a de novo acute infection or a reactivation of a previous chronic infection. In both cases, the use of antiviral therapy is recommended, with entecavir or tenofovir, among others, but the use of specific HBIG is supported only in ALF related to chronic HBV infection. The optimal length of the antiviral therapy after liver transplantation is still under discussion. CONCLUSION: These cases of HBV related ALF with an early HBsAg seroconversion demonstrates the relevance of requesting IgM antibody against hepatitis B core antigen (anti-HBc IgM) for the etiological study of ALF with negative HBsAg. Usage of HBIG does not seem essential during the post-transplantation period in these cases.

Treatment and Prevention of Acute Hepatitis B Virus

This article reviews the incidence of acute hepatitis B virus (HBV) infection, its clinical course, strategies to prevent acute HBV infection in susceptible individuals, and the management of patients with acute HBV.

Variable Proportions of Phylogenetic Clustering and Low Levels of Antiviral Drug Resistance among the Major HBV Sub-Genotypes in the Middle East and North Africa

Hepatitis B virus (HBV) infection remains a major public health threat in the Middle East and North Africa (MENA). Phylogenetic analysis of HBV can be helpful to study the putative transmission links and patterns of inter-country spread of the virus. The objectives of the current study were to analyze the HBV genotype/sub-genotype (SGT) distribution, reverse transcriptase (RT), and surface (S) gene mutations and to investigate the domestic transmission of HBV in the MENA. All HBV molecular sequences collected in the MENA were retrieved from GenBank as of 30 April 2021. Determination of genotypes/SGT, RT, and S mutations were based on the Geno2pheno (hbv) 2.0 online tool. For the most prevalent HBV SGTs, maximum likelihood phylogenetic analysis was conducted to identify the putative phylogenetic clusters, with approximate Shimodaira-Hasegawa-like likelihood ratio test values ≥ 0.90, and genetic distance cut-off values ≤ 0.025 substitutions/site as implemented in Cluster Picker. The total number of HBV sequences used for genotype/SGT determination was 4352 that represented a total of 20 MENA countries, with a majority from Iran (n = 2103, 48.3%), Saudi Arabia (n = 503, 11.6%), Tunisia (n = 395, 9.1%), and Turkey (n = 267, 6.1%). Genotype D dominated infections in the MENA (86.6%), followed by genotype A (4.1%), with SGT D1 as the most common in 14 MENA countries and SGT D7 dominance in the Maghreb. The highest prevalence of antiviral drug resistance was observed against lamivudine (4.5%) and telbivudine (4.3%). The proportion of domestic phylogenetic clustering was the highest for SGT D7 (61.9%), followed by SGT D2 (28.2%) and genotype E (25.7%). The largest fraction of domestic clusters with evidence of inter-country spread within the MENA was seen in SGT D7 (81.3%). Small networks (containing 3-14 sequences) dominated among domestic phylogenetic clusters. Specific patterns of HBV genetic diversity were seen in the MENA with SGT D1 dominance in the Levant, Iran, and Turkey; SGT D7 dominance in the Maghreb; and extensive diversity in Saudi Arabia and Egypt. A low prevalence of lamivudine, telbivudine, and entecavir drug resistance was observed in the region, with almost an absence of resistance to tenofovir and adefovir. Variable proportions of phylogenetic clustering indicated prominent domestic transmission of SGT D7 (particularly in the Maghreb) and relatively high levels of virus mobility in SGT D1.

2020 position statement and recommendations of the European Liver and Intestine Transplantation Association (ELITA): management of hepatitis B virus-related infection before and after liver transplantation

BACKGROUND

Prophylaxis of HBV recurrence is critical after liver transplantation in HBV patients. Despite new prophylactic schemes, most European LT centres persist on a conservative approach combining hepatitis B immunoglobulin (HBIG) and nucleos(t)ides analogues (NA).

AIM

This setting prompted the European Liver Intestine Transplantation Association (ELITA) to look for a consensus on the prevention of HBV recurrence.

METHODS

Based on a 4-round Delphi process, ELITA investigated 16 research questions and established 50 recommendations.

RESULTS

Prophylaxis should be driven according to 3 simplified risk groups: Low and high virological risk patients, with undetectable and detectable HBV DNA pre-LT, respectively, and special populations (HDV, HCC, poorly adherent patients). In low-risk patients, short-term (4 weeks) combination of third-generation NA+ HBIG, or third generation NA monotherapy can be considered as prophylactic options. In high-risk patients, HBIG can be discontinued once HBV DNA undetectable. Combined therapy for 1 year is advised. HBV-HCC patients should be treated according to their virological risk. In HDV/HBV patients, indefinite dual prophylaxis remains the gold standard. Full withdrawal of HBV prophylaxis following or not HBV vaccination should only be attempted in the setting of clinical trials. Organs from HBsAg+ve donors may be considered after assessment of risks, benefits, and patient consent. They should not be used if HDV is present. In poorly adherent patients, dual long-term prophylaxis is recommended. Budget impact analysis should be taken into account to drive prophylactic regimen.

CONCLUSIONS

These ELITA recommendations should stimulate a more rational and homogeneous approach to HBV prophylaxis across LT programs.

Persistence of Hepatitis B Virus Infection: A Multi-Faceted Player for Hepatocarcinogenesis

Hepatitis B virus (HBV) infection has a multi-dimensional effect on the host, which not only alters the dynamics of immune response but also persists in the hepatocytes to predispose oncogenic factors. The virus exists in multiple forms of which the nuclear localized covalently closed circular DNA (cccDNA) is the most stable and the primary reason for viral persistence even after clearance of surface antigen and viral DNA. The second reason is the existence of pregenomic RNA (pgRNA) containing virion particles. On the other hand, the integration of the viral genome in the host chromosome also leads to persistent production of viral proteins along with the chromosomal instabilities. The interferon treatment or administration of nucleot(s)ide analogs leads to reduction in the viral DNA load, but the pgRNA and surface antigen clearance are a slow process and complete loss of serological HBsAg is rare. The prolonged exposure of immune cells to the viral antigens, particularly HBs antigen, in the blood circulation results in T-cell exhaustion, which disrupts immune clearance of the virus and virus-infected cells. In addition, it predisposes immune-tolerant microenvironment, which facilitates the tumor progression. Thus cccDNA, pgRNA, and HBsAg along with the viral DNA could be the therapeutic targets in the early disease stages that may improve the quality of life of chronic hepatitis B patients by impeding the progression of the disease toward hepatocellular carcinoma.

Factors influencing the durability of hepatitis B vaccine responses

The World Health Organization recommends the implementation of universal hepatitis B (HB) vaccination, and global coverage for this vaccine reached 84% in 2015. In Japan, the policy aimed at preventing mother-to-child transmission of HB virus (HBV) initially commenced as a specific vaccination program for infants born to mothers who were positive for HB surface antigen. In 2016, universal HB vaccination was implemented in this country to cover unvaccinated individuals at risk of horizontal HBV transmission. Although HB vaccination has been shown to be highly efficacious and safe, the issues of vaccine non-responders and of the loss of antibodies directed against HB surface antigen (anti-HBs) in HB vaccine recipients remain. To gain better insight into these problems, we previously performed an immunological analysis on adult vaccine recipients after they received an initial HB vaccination. We found that the course of successful HB vaccination is composed of the following distinct phases: 1) acquisition of anti-HBs antibody, 2) attainment of high anti-HBs antibody titers, and 3) maintenance of acquired anti-HBs antibody levels. In this review, we describe the significance of HB vaccination and suggest a potential means of improving the impact of HB vaccination based on our immunological analysis.

Molecular Mechanisms during Hepatitis B Infection and the Effects of the Virus Variability

The immunopathogenesis and molecular mechanisms involved during a hepatitis B virus (HBV) infection have made the approaches for research complex, especially concerning the patients’ responses in the course of the early acute stage. The study of molecular bases involved in the viral clearance or persistence of the infection is complicated due to the difficulty to detect patients at the most adequate points of the disease, especially in the time lapse between the onset of the infection and the viral emergence. Despite this, there is valuable data obtained from animal and in vitro models, which have helped to clarify some aspects of the early immune response against HBV infection. The diversity of the HBV (genotypes and variants) has been proven to be associated not only with the development and outcome of the disease but also with the response to treatments. That is why factors involved in the virus evolution need to be considered while studying hepatitis B infection. This review brings together some of the published data to try to explain the immunological and molecular mechanisms involved in the different stages of the infection, clinical outcomes, viral persistence, and the impact of the variants of HBV in these processes.

Prevalence of hepatitis B virus genotypes among patients with liver disease in Eritrea

Eritrea is an East African multiethnic country with an intermediate endemicity for hepatitis B. Our aim was to establish the most prevalent genotypes of hepatitis B virus (HBV) among patients with liver disease. A total of 293 Eritrean patients with liver disease who were hepatitis B surface antigen (HBsAg) positive were enrolled. All sera were tested for liver transaminases, HBV DNA viral load, and hepatitis B seromarkers including HBsAg, anti-HBcAb (total), HBeAg, and anti-HBeAb. Those reactive for HBsAg and anti-HBc (total) were further tested for HBV genotyping. The median (interquartile range) of HBV DNA viral load and ALT levels were 3.47 (1.66) log IU/mL and 28 (15.3) IU/L, respectively. Using type-specific primer-based genotyping method, 122/293 (41.6%) could be genotyped. Irrespective of mode of occurrence, HBV genotype D (21.3%) was the predominant circulating genotype, followed by genotypes C (17.2%), E (15.6%), C/D (13.1%), and C/E (10.7%). Genotypes C/D/E (7.4%), A/D (4.9%), D/E (4.1%), A (2.5%), and B, A/E, B/E, and A/D/C (0.8%) were also present. HBV in Eritrea is comprised of a mixture of HBV genotypes. This is the first study of HBV genotyping among patients with liver disease in Eritrea.

Acute-on-Chronic Liver Failure From Chronic-Hepatitis-B, Who Is the Behind Scenes

Acute-on-chronic liver failure (ACLF) is an acute syndrome accompanied with decompensation of cirrhosis, organ failure with high 28-day mortality rate. Systemic inflammation is the main feature of ACLF, and poor outcome is closely related with exacerbated systemic inflammatory responses. It is well known that severe systemic inflammation is an important event in chronic hepatitis B (CHB)-ACLF, which eventually leads to liver injury. However, the initial CHB-ACLF events are unclear; moreover, the effect of these events on host immunity as well as that of immune imbalance on CHB-ACLF progression are unknown. Here, we investigate the initial events of ACLF progression, discuss possible mechanisms underlying ACLF progression, and provide a new model for ACLF prediction and treatment. We review the characteristics of ACLF, and consider its plausible immune predictors and alternative treatment strategies.

Biological features of hepatitis B virus strains associated with fulminant hepatitis

Accumulating evidence suggests that hepatitis B virus (HBV) biological features may influence the course and clinical manifestations of infection and possibly the development of fulminant hepatitis (FH). Since HBV is not a cytocidal virus, virus-induced liver damage results from an interplay between the virus replication and the host's defense. Therefore, viral factors contributing to enhanced replication, induction of a stronger immune attack or apoptosis of hepatocytes could be crucial in development of FH. Numerous mutations in basal core promoter, pre-C, C and S regions of the HBV genome contribute to development of FH by different mechanisms, including enhanced viral replication, the loss of a decoy for immune response, unbalanced expression of viral proteins and retention of unprocessed cytotoxic proteins in hepatocytes.

The genetic variability of hepatitis B virus subgenotype F1b precore/core gene is related to the outcome of the acute infection

AIM

To assess the association of viral and host genetic variability with the outcome of acute infection with hepatitis B virus subgenotype F1b (HBV/F1b).

METHODS

The cohort consisted of 26 patients with acute HBV/F1b infection who exhibit different outcomes: spontaneous resolution (n = 10), progression to chronic hepatitis (n = 10) and acute liver failure (n = 6). HLA SNPs (rs3077, rs9277542, rs2856718 and rs7453920) were determined. The S gene and core promoter/precore/core region were direct sequenced, and this latter region was also ultra-deep sequenced. Mean number of mutations, mutation rate, Shannon entropy, positive selection sites and mutational patterns of quasispecies were compared between groups.

RESULTS

HLA SNPs were associated with spontaneous resolution or progression to chronic hepatitis, but not with the development of acute liver failure. The mean number of mutations in the S gene was similar among the three groups. Patients with spontaneous resolution had the lowest number of mutations, mutation rates and Shannon entropy values in the precore/core compared to the other two groups. Ten positive selection sites mapped on HLA-restricted epitopes were related to progression to chronic hepatitis and acute liver failure. Mutations T1753C, A1762T, G1764A, C1766T, T1768A G1896A, G2092T and T2107C were associated with acute liver failure and progression to chronic hepatitis.

CONCLUSION

Highly heterogeneous and complex HBV precore/core carrying specific point mutations, combined with the host HLA background, were associated with a worse clinical outcome of acute HBV/F1b infection.

Management of Fulminant Hepatitis B

Purpose of Review

Acute HBV infection and acute exacerbations of chronic HBV infection can cause acute liver injury (ALI) or fulminant hepatitis (FH). At this stage, spontaneous survival is poor, less than 25%. The purpose of this review is to provide an overview of specific management of patients with HBV-ALI/FH.

Recent Findings

Acute HBVinfection and acute exacerbations of chronic HBVinfection can cause acute liver injury (ALI) or fulminant hepatitis (FH). Spontaneous survival at this stage is poor. It is urgent to distinguish between these two entities so that antiviral therapy can be initiated rapidly. Although the indications for antiviral therapy are clear for HBV reactivation, there is no true consensus regarding ALI/FH related to acute HBV infection. The global management of HBV-related FH does not differ from that implemented for other causes of FH, i.e. close cardiorespiratory and neurological monitoring, treatment with acetylcysteine, organ support in the event of organ failure (haemodynamic, renal, respiratory) and albumin dialysis. Liver transplantation remains the only alternative when certain criteria for a poor prognosis are met. A recurrence of HBV infection on the graft can be prevented post-transplant by the administration of HBIG and antiviral therapy for HBV, the modalities varying depending on the risk of recurrence.

Hepatitis B virus infection in children and adolescents

Hepatitis B virus (HBV) infection is a major cause of acute and chronic liver disease and associated morbidity and mortality worldwide. Vertical (mother-to-child) and horizontal early childhood transmission are the main routes of HBV transmission and are responsible for most chronic infections, including among adults who bear the greatest burden of morbidity and mortality. Universal hepatitis B immunisation at birth and in infancy is the key strategy for global elimination of HBV infection, and has been highly effective in reducing new vertical infections. However, global progress in scale-up of HBV testing and treatment has been slow in adults and children. In this Series paper, we summarise knowledge on the epidemiology, natural history, and treatment of chronic HBV infection in adolescents and children, and we highlight key differences from HBV infection in adults. The estimated global prevalence of HBV infection in children aged 5 years or younger is 1·3%. Most children are in the high-replication, low-inflammation phase of infection, with normal or only slightly raised aminotransferases; cirrhosis and hepatocellular carcinoma are rare. Although entecavir is approved and recommended for children aged 2-17 years, and tenofovir for those aged 12-18 years, a conservative approach to treatment initiation in children is recommended. Key actions to address current policy gaps include: validation of non-invasive tests for liver disease staging; additional immunopathogenesis studies in children with HBV infection; long-term follow-up of children on nucleoside or nucleotide analogue regimens to inform guidance on when to start treatment; evaluation of different treatment strategies for children with high rates of HBV replication; and establishment of paediatric treatment registries and international consortia to promote collaborative research.

Clinical Outcome and Viral Genome Variability of Hepatitis B Virus-Induced Acute Liver Failure

Acute hepatitis B virus (HBV) infection remains a frequent cause of acute liver failure (ALF) worldwide. ALF occurs in 0.1%-0.5% of infected patients. The aim of this study was to scrutinize the outcome of patients with HBV-induced ALF and mutational patterns of HBV variants, which might contribute to ALF. From 2005 to 2016, 42 patients were treated for HBV-induced ALF in the University Hospital Essen, Germany. Clinical and virological data from these patients were collected. As a control, 38 patients with acute hepatitis B (AHB) without liver failure were included. The HBV genome was sequenced by next-generation sequencing (NGS). Mutations that were found by NGS were analyzed in vitro. Of 42 patients, 8 had ALF without spontaneous recovery (NSR): Seven patients underwent liver transplantation (LT) and one patient died before LT. Of 42 patients, 34 (81%) had spontaneous recovery (SR) and cleared the infection, achieving either anti-HBs seroconversion or hepatitis B surface antigen (HBsAg) loss. HBV genotype (GT)-D was the most frequent GT in patients with ALF. Mutations in HBV core, preS2, and small hepatitis B surface antigen (SHB) were more frequent in patients with ALF-NSR compared with those with ALF-SR or AHB. Amino acid deletions (del; 16-22 and 20-22) in preS2 and SHB mutation L49R were exclusively detected in patients with ALF-NSR. In vitro analyses reveal that these mutations did not influence HBsAg secretion or infectivity. Conclusion: HBV GT-D and increased variability in HBV core, preS2 region, and SHB are associated with a worse clinical outcome of acute HBV infection.

Clinical Manifestations and Laboratory Tests of AECHB and Severe Hepatitis (Liver Failure)

This chapter describes the clinical symptoms and signs of AECHB and HBV ACLF, classification, grading of HBV ACLF and their features, diagnostic principles and standards in liver pathology, biochemistry, and virology of HBV ACLF.

Liver failure is defined as serious damage to the liver cause by a variety of etiologies, leading to liver function disorder or even decompensation, and clinical syndromes with coagulopathy, jaundice, hepatic encephalopathy, and ascites.

Severe hepatitis B can be indicated pathologically by apparent hepatocellular necrosis, including extensive multifocal, confluent, bridging, sub-massive or massive necrosis.

Laboratory tests during the course of severe exacerbation of chronic hepatitis B can reflect pathological changes and liver function in a timely manner, providing objective and informative reference data for evaluation of disease severity and treatment efficacy. Among the most important laboratory tests are those for prothrombin activity, international normalized ratio, and increases in total bilirubin concentration.

Severe hepatitis B is associated with interactions between the virus and host factors. Detection of HBV DNA, HBV genotype, quasispecies and HBV mutation can provide important theoretical bases for the prevention, control or mitigation of the progress of severe hepatitis B.

Noninvasive imaging modalities can be used to visualize the entire liver and parts of it. Measuring liver volume to evaluate liver size and liver reserve capacity is regarded as important in diagnosis, surgical approach and prognostic evaluation of patients with severe exacerbation of chronic hepatitis B and liver failure.

Model for End-Stage Liver Disease (MELD) is the first quantitative method developed to assess whether a patient with liver failure requires a liver transplant. The predictive value of the MELD model has been improved by the MELD-Na, iMELD, and MESO models. Several other valuable prognostic models have been developed. For example, for patients with HBV-ACLF, the established TPPM scoring system was found to be more predictive than MELD score.

Role of humoral immunity against hepatitis B virus core antigen in the pathogenesis of acute liver failure

Hepatitis B virus (HBV)-associated acute liver failure (ALF) is a dramatic clinical syndrome leading to death or liver transplantation in 80% of cases. Due to the extremely rapid clinical course, the difficulties in obtaining liver specimens, and the lack of an animal model, the pathogenesis of ALF remains largely unknown. Here, we performed a comprehensive genetic and functional characterization of the virus and the host in liver tissue from HBV-associated ALF and compared the results with those of classic acute hepatitis B in chimpanzees. In contrast with acute hepatitis B, HBV strains detected in ALF livers displayed highly mutated HBV core antigen (HBcAg), associated with increased HBcAg expression ex vivo, which was independent of viral replication levels. Combined gene and miRNA expression profiling revealed a dominant B cell disease signature, with extensive intrahepatic production of IgM and IgG in germline configuration exclusively targeting HBcAg with subnanomolar affinities, and complement deposition. Thus, HBV ALF appears to be an anomalous T cell-independent, HBV core-driven B cell disease, which results from the rare and unfortunate encounter between a host with an unusual B cell response and an infecting virus with a highly mutated core antigen.

Early predictors of acute hepatitis B progression to liver failure

BACKGROUND AND AIMS

1~4% of acute hepatitis B (AHB) cases in adults progresses to acute liver failure (ALF).The predictors of ALF and prognosis for patients with ALF are not clear. This study investigated some of predictive and prognostic factors for AHB progression to ALF.

METHODS

A retrospective analysis was used to assess the clinical and laboratory features of 293 patients diagnosed with AHB; the patients were divided into the following two groups: ALF (n = 13) and non-ALF (n = 280).

RESULTS

In total,13 of the 293 (4.43%) patients developed ALF (10 recovered、3 died). The variables of age, anti-HBc IgM titers≥10 S/CO, HBeAg negativity, and total bilirubin (TB) at admission were significantly higher in ALF patients than in non-ALF patients. Compared to non-ALF patients, ALF patients had significantly lower values for prothrombin time activity (PTA), serum albumin, and HBV DNA. At discharge, ALF patients had lower TB normalization rates and much faster clearance of HBsAg, HBeAg and HBVDNA than non-ALF patients. In multivariate analysis, TB≥5×upper limit of normal (ULN) and HBeAg negative status were independent predictors for ALF development at admission, with 84.6% sensitivity, 85.7% specificity, a likelihood ratio of 5.91 and an area under the receiver operating characteristics curve (AUROC) of 0.850.Those who died had lower levels of peak PTA (<20%) and higher levels of peak hepatic encephalopathy (HE) grade (III-IV) than those who recovered.

CONCLUSIONS

Of the patients with ALF, 23.1% died. TB≥5×ULN and HBeAg negative status were the most effective and practicable factors distinguishing ALF from AHB at admission before the onset of encephalopathy. Peak PTA<20% and/or HE grade III-IV were independent predictors of a high probability of death or a need for transplantation.

Long-Term Follow-Up of Acute Hepatitis B: New Insights in Its Natural History and Implications for Antiviral Treatment

Acute hepatitis B infection (AHB) is still a common viral acute hepatitis worldwide. As vaccination, antiviral treatment, and immigration are bound to affect the epidemiological landscape of HBV infections, and some of its aspects need to be investigated: (1) the circulation of vaccine escape mutants and of primary drug resistant strains; (2) the change in HBV genotype prevalence; and (3) the clinical implications of AHB and the probability of chronification. The serological, virological, and clinical parameters of 75 patients, acutely infected by HBV, were gathered for a retrospective study. Long-term follow up, either to complete seroconversion or for up to five years, was possible for 44 patients. Sequence analysis of the reverse transcriptase/HBsAg and precore regions was performed to investigate the molecular epidemiology and pathogenesis of recent infections by HBV. Genotype distribution in AHB in Italian patients was radically different from that of chronic infections, with a dramatic increase of extra-European genotypes (A1, F), suggesting that a proportion of AHBs are currently related to imported strains. None of the documented infections occurred in vaccinated individuals, while HBsAg variants (potentially vaccine escape variants) were rare and less prevalent than in chronic infections. No drug resistant strains were observed. Spontaneous viral clearance occurred in all but three cases. Time to viral clearance was inversely proportional to liver damage, but HBsAg titer on day 28 and, better still, HBsAg decay from day 0 to day 28 after admission, were the best predictors of chronification. They are, thus, potentially useful to guide antiviral treatment to prevent chronic evolution.

Applying the Molecular Adsorbent Recirculating System (MARS) in the Treatment of Acute Liver Failure (ALF) Case Report

Acute liver failure (ALF) is a rare but life-threatening illness with multiple organ failure. The short-term mortality rate exceeded 80 % despite modern approaches in treatment. Drugs, infections by hepatic viruses and toxins are the most common causes of ALF. Progressive jaundice, coagulation disorder and hepatic encephalopathy are dominated as a clinical signs of the illness. We present a case of a 36-year-old Caucasian woman hospitalized in ICU due to yellow discoloration of the skin and sclera, severe disseminated coagulopathy and hemodynamic instability. ALF is developed due to Hepatitis B Virus infection, resulting in hepatic toxicity as well as coma. General condition rapidly improved after applying of Molecular Adsorbent Recirculating System (MARS), an extracorporeal liver support system based on albumin dialysis. It is relatively expensive treatment that is used for the patient with hepatic encephalopathy grade 3 or 4 in our institution. In conclusion, an early administration of MARS significantly reveals subjective and objective clinical improvement in the case we presented.

Early Combination Therapy with Corticosteroid and Nucleoside Analogue Induces Rapid Resolution of Inflammation in Acute Liver Failure due to Transient Hepatitis B Virus Infection

Objective Patients with acute hepatitis B sometimes develop acute liver failure (ALF), which has a poor prognosis. The efficacy of nucleoside analogue (NA) monotherapy for ALF due to transient hepatitis B virus infection (HBV-ALF) remains controversial. Further investigations are necessary in nations with a shortage of donor livers for liver transplantation. In the present study, we aimed to clarify the efficacy of combination therapy with corticosteroid (CS) and NA in the treatment HBV-ALF. Patients We examined the clinical and biochemical features of 19 patients with HBV-ALF who were treated in the early stage of the disease between 2000 and 2015. Results Fourteen patients received CS and NA (CS + NA group) and 5 received NA monotherapy (NA group). Eleven patients (58%) survived and 8 (42%) died. The survival rates in the CS + NA and NA groups were 64% and 40%, respectively (p=0.60). The mean alanine aminotransferase (ALT) levels declined significantly at week 2 in both groups. The mean PT activities improved significantly at weeks 1 and 2 in the CS + NA group (p<0.05) but not in the NA group. None of the surviving patients developed persistent infection. Conclusion Combination therapy with CS and NA induces the rapid resolution of inflammation leading to a rapid recovery of the liver function. When it is administered at a sufficiently early stage, it would have a survival benefit and prevent persistent infection in HBV-ALF.

Atypical manifestations of hepatitis A virus infection

Acute hepatitis due to the hepatitis A virus usually has a short, benign and self-limited course, without causing chronic hepatitis. However, some cases have an atypical presentation, such as relapsing hepatitis, prolonged or persistent cholestasis, fulminant hepatic failure, or liver failure associated with autoimmune hepatitis. The typical clinical course of acute hepatitis A virus infection is spontaneous remission in 90% of the cases, but atypical cases have a prevalence that varies from less than 1 to 20%, depending on the manifestation (overall prevalence ∼7%). There is little information on the atypical clinical courses of hepatitis A virus infection and the lack of recognizing those presentations in clinical practice often results in carrying out numerous studies and treatments that not only are unnecessary, but can also be harmful. The aim of the present article was to describe 3 clinical cases of atypical hepatitis A infection and provide a literature review of such cases.

What is changed in HBV molecular epidemiology in Italy?

Hepatitis B virus (HBV) infection represents the most common cause of chronic liver diseases worldwide. Consequently, to the introduction of the universal HBV vaccination program, the prevalence of hepatitis B surface antigen was markedly reduced and less than 1% of the population of Western Europe and North America is chronically infected. To date, despite great advances in therapeutics, HBV chronic infection is considered an incurable disease. Ten hepatitis B virus genotypes (A-J) and several subgenotypes have been identified so far, based on intergroup divergences of 8% and 4%, respectively, in the complete viral genome. HBV-D genotype has been found throughout the world, with highest prevalence in the Mediterranean area. In the present review, several articles concerning HBV epidemiology, and phylogeny in Italy have been analyzed, mainly focusing on the changes occurred in the last decade.

How viral genetic variants and genotypes influence disease and treatment outcome of chronic hepatitis B. Time for an individualised approach?

Chronic hepatitis B virus (HBV) infection remains a global problem. Several HBV genotypes exist with different biology and geographical prevalence. Whilst the future aim of HBV treatment remains viral eradication, current treatment strategies aim to suppress the virus and prevent the progression of liver disease. Current strategies also involve identification of patients for treatment, namely those at risk of progressive liver disease. Identification of HBV genotype, HBV mutants and other predictive factors allow for tailoured treatments, and risk-surveillance pathways, such as hepatocellular cancer screening. In the future, these factors may enable stratification not only of treatment decisions, but also of patients at risk of higher relapse rates when current therapies are discontinued. Newer technologies, such as next-generation sequencing, to assess drug-resistant or immune escape variants and quasi-species heterogeneity in patients, may allow for more information-based treatment decisions between the clinician and the patient. This article serves to discuss how HBV genotypes and genetic variants impact not only upon the disease course and outcomes, but also current treatment strategies. Adopting a personalised genotypic approach may play a role in future strategies to combat the disease. Herein, we discuss new technologies that may allow more informed decision-making for response guided therapy in the battle against HBV.

EASL Clinical Practical Guidelines on the management of acute (fulminant) liver failure

The term acute liver failure (ALF) is frequently applied as a generic expression to describe patients presenting with or developing an acute episode of liver dysfunction. In the context of hepatological practice, however, ALF refers to a highly specific and rare syndrome, characterised by an acute abnormality of liver blood tests in an individual without underlying chronic liver disease. The disease process is associated with development of a coagulopathy of liver aetiology, and clinically apparent altered level of consciousness due to hepatic encephalopathy. Several important measures are immediately necessary when the patient presents for medical attention. These, as well as additional clinical procedures will be the subject of these clinical practice guidelines.

Association of Mutations in Toll-like Receptor 2 Signaling Genes With Fulminant Form of Hepatitis B-Related Acute Liver Failure

BACKGROUND

The fulminant form of hepatitis B-related acute liver failure (FHB-ALF) is a rare but highly fatal outcome of acute hepatitis B virus (HBV) infection. Its related host factors have not been studied to our knowledge.

METHODS

To identify functionally relevant biological pathway(8) in FHB-ALF pathogenesis, pathway enrichment analysis was conducted on a data set of rare case-specific variants derived from exomic sequencing of 10 unrelated cases. Key variants in identified pathways were validated using 312 controls with HBV disease. Mechanistic studies of a recurrent Toll-like receptor (TLR) 2 gene (TLR2) variant were performed in vitro and in vivo.

RESULTS

The TLR signaling pathway was highly enriched, with associated variants found in 9 of the 10 cases. Notably, a rare heterozygous single-nucleotide variation causing F679I mutation in TLR2 was identified in 2 unrelated cases. In vitro analysis demonstrated F679I to cause loss of function. In both heterozygous and homozygous TLR2 knockout mice, injection of HBV replicon plasmid resulted in more prominent alanine aminotransferase elevations and hepatic necroinflammation than in wild-type mice. Mechanistic analyses demonstrated reduced regulatory T-cell percentages in postexposure TLR2 knockout mice.

CONCLUSIONS

TLR2 signaling is very likely impaired in patients with FHB-ALF. The recurrence of rare case-specific TLR2 variant strongly suggests mechanistic contribution to fulminancy in HBV infection.

Prodromal fever indicates a high risk of liver failure in acute hepatitis B

OBJECTIVES

The role of prodromal fever in the clinical course of acute hepatitis B virus (HBV) infection is still largely unclear. This study was conducted to investigate the factors associated with prodromal fever and its role in the development of acute liver failure (ALF) in patients with acute hepatitis B (AHB).

METHODS

Inpatients with AHB diagnosed between January 2006 and December 2010 were evaluated and followed. Clinical manifestations, results of laboratory tests, and outcomes were compared between patients with and without prodromal fever. The diagnosis of AHB was based on the discrete onset of symptoms, jaundice, abnormal liver function tests, the detection of high-titer IgM antibody to hepatitis B core antigen (anti-HBc), and a compatible clinical history.

RESULTS

A total of 618 AHB inpatients were identified during the study period, of whom 102 (16.5%) had prodromal fever and 41 (6.6%) developed ALF. Prodromal fever indicated more severe liver injury and was independently associated with hepatitis B e antigen (HBeAg) negativity. The occurrence of ALF was more common in febrile patients than in non-febrile patients (18.6% vs. 4.3%, p<0.001). Multivariate logistic regression showed prodromal fever and temperature >38.0°C to be independently associated with the risk of ALF, with an odds ratio (95% confidence interval) of 3.5 (1.4-8.6) and 7.1 (2.6-19.7), respectively.

CONCLUSIONS

AHB patients with prodromal fever, which is associated with a lack of HBeAg due to HBV mutation, are at high risk of ALF. Febrile patients with AHB should be managed with particular care.

Hepatitis B immunopathogenesis and immunotherapy

Worldwide there are over 248 million chronic carriers of HBV of whom about a third eventually develop severe HBV-related complications. Due to the major limitations of current therapeutic approaches, the development of more effective strategies to improve therapeutic outcomes in chronic hepatitis B (CHB) patients seems crucial. Immune activation plays a critical role in spontaneous viral control; therefore, new modalities based on stimulation of the innate and adaptive immune responses could result in the resolution of infection and are promising approaches. Here, we summarize the HBV immunopathogenesis, and discuss the encouraging results obtained from the promising immune-based innovations, such as therapeutic vaccination, cytokine therapy, cell-based therapies and blocking inhibitory receptors, as current and future immunotherapeutic interventions.

Diagnosis of hepatitis B

Hepatitis B virus (HBV) infection is a major global health problems leading to severe liver disease such as cirrhosis and hepatocellular carcinoma (HCC). HBV is a circular, partly double-stranded DNA virus with various serological markers: hepatitis B surface antigen (HBsAg) and anti-HBs, anti-HBc IgM and IgG, and hepatitis B e antigen (HBeAg) and anti-HBe. It is transmitted by sexual, parenteral and vertical route. One significant method to diminish the burden of this disease is timely diagnosis of acute, chronic and occult cases of HBV. First step of HBV diagnosis is achieved by using serological markers for detecting antigens and antibodies. In order to verify first step of diagnosis, to quantify viral load and to identify genotypes, quantitative or qualitative molecular tests are used. In this article, the serological and molecular tests for diagnosis of HBV infection will be reviewed.

Acute Liver Failure: Diagnosis and Management

Acute liver failure is life threatening liver injury with coagulopathy and hepatic encephalopathy within 26 weeks and generally, in the absence of preexisting liver disease. Fulminant liver failure occurs when hepatic encephalopathy occurs within 8 weeks of jaundice. The majority of patients with ALF are women with the median age of 38 years. In the United States, drug induced liver injury including acetaminophen causes the majority of ALF cases. The etiology of ALF should be determined, if possible, because many causes have a specific treatment. The mainstay for ALF is supportive care and liver transplantation, if necessary. There are multiple prognostic criteria available. Prognosis can be poor and patients should be referred to a liver transplantation center as soon as possible.

Characteristics, Diagnosis and Prognosis of Acute-on-Chronic Liver Failure in Cirrhosis Associated to Hepatitis B

The diagnostic and prognostic criteria of acute-on-chronic liver failure (ACLF) were developed in patients with no Hepatitis B virus (HBV) cirrhosis (CANONIC study). The aims of this study were to evaluate whether the diagnostic (CLIF-C organ failure score; CLIF-C OFs) criteria can be used to classify patients; and the prognostic score (CLIF-C ACLF score) could be used to provide prognostic information in HBV cirrhotic patients with ACLF. 890 HBV associated cirrhotic patients with acute decompensation (AD) were enrolled. Using the CLIF-C OFs, 33.7% (300 patients) were diagnosed as ACLF. ACLF was more common in the younger patients and in those with no previous history of decompensation. The most common organ failures were ‘hepatic’ and ‘coagulation’. As in the CANONIC study, 90-day mortality was extremely low in the non-ACLF patients compared with ACLF patients (4.6% vs 50%, p < 0.0001). ACLF grade and white cell count, were independent predictors of mortality. CLIF-C ACLFs accurately predicted short-term mortality, significantly better than the MELDs and a disease specific score generated for the HBV patients. Current study indicates that ACLF is a clinically and pathophysiology distinct even in HBV patients. Consequently, diagnostic criteria, prognostic scores and probably the management of ACLF should base on similar principles.

Prevalence of mutations within major hydrophilic region of hepatitis B virus and their correlation with genotypes among chronically infected patients in Egypt

BACKGROUND AND STUDY AIMS

Mutations within the major hydrophilic region (MHR) of the hepatitis B surface antigen (HBsAg) have been reported in relation to viral persistence by evasion from vaccine and immunotherapy, severity of liver disease and lack of detection by commercial kits. The aim of this study was to elucidate the circulation of hepatitis B virus (HBV) genotypes, subgenotypes and serotypes in Egypt, with recognition of the pattern and prevalence of MHR mutations possibly occurring during the course of the disease.

PATIENTS AND METHODS

Eighty-eight samples from patients with chronic HBV infection were included in the study. The surface protein-encoding gene (S gene) in the HBV genome was subjected to amplification and partial sequencing.

RESULTS

Based on phylogenetic analysis, only genotype D was found circulating among patients. The majority of isolates belonged to subgenotype D3 (86.3%), followed by D7 (8%), then D5 (3.4%) and lastly D1 (2.3%). Two subtypes were identified: ayw2 (97%) and ayw3 (2%). The 'w' sub-determinant was not defined in one isolate (1%). A significant proportion of patients (13/88, 14.8%) exhibited mutations in the MHR, 10 of whom harboured mutations in the 'a' determinant region and three outside. The first loop comprised four patients with three mutations (P127S, P127T and Y134F). The second loop contained six patients, all with one mutation, S143L, which was most frequently encountered in this study (6.8%).

CONCLUSIONS

We conclude that genotype D, subgenotype D3 and HBsAg subtype ayw2 are the most common types circulating in Egypt, which account for 100%, 86.3% and 97% of the population, respectively, with a moderate degree of MHR mutations.

Polymorphisms in sodium taurocholate cotransporting polypeptide are not associated with hepatitis B virus clearance in Chinese Tibetans and Uygurs

An association between polymorphisms in the sodium taurocholate cotransporting polypeptide (NTCP) and the natural course of hepatitis B virus (HBV) infection in the Chinese Han population has been noted. However, it is not known whether these polymorphisms are associated with the risk of developing chronic HBV infection in other racial or ethnic populations. Accordingly, we conducted a candidate single nucleotide polymorphism (SNP) association study in Tibetan and Uygur HBV-infected patients. A total of 1302 subjects including 871 Tibetans and 431 Uygurs were recruited. According to their serological and clinical characteristics, each ethnic group was divided into two groups comprising spontaneous clearance individuals and persistently infected patients. Three SNPs were genotyped by a high resolution melting curve methodology. Among the SNPs, rs2296651 exhibited a minor allele frequency of <0.01. The frequency of allele A at rs4646287 was much higher in Tibetans (9.4% for Tibetans and 4.6% for Uygurs, p<0.001) than in Uygurs, but the frequency of allele A at rs7154439 was the opposite (15.7% for Tibetans and 20.5% for Uygurs, p=0.002). Irrespective of race, no significant differences in the frequency distributions of the three SNP alleles or genotypes were observed between the case and clearance groups. Moreover, none of the NTCP haplotypes were statistically different between the two groups. Data from the Tibetan patients could be grouped by HBeAg status, viral load and HBV genotype; however, no significant differences were found in the SNP genotype distribution for each characteristic. In conclusion, the NTCP polymorphisms we identified tended to be ethnicity-dependent. For Tibetans and Uygurs, no association of the three SNPs (rs7154439, rs4646287 and rs2296651) and their haplotypes with HBV chronicity was observed. Examination of SNPs in NTCP for their specific associations with the course of HBV infection in other ethnic minority groups is now required.

Genetic variation of hepatitis B virus and its significance for pathogenesis

Hepatitis B virus (HBV) has a worldwide distribution and is endemic in many populations. Due to its unique life cycle which requires an error-prone reverse transcriptase for replication, it constantly evolves, resulting in tremendous genetic variation in the form of genotypes, sub-genotypes, and mutations. In recent years, there has been considerable research on the relationship between HBV genetic variation and HBV-related pathogenesis, which has profound implications in the natural history of HBV infection, viral detection, immune prevention, drug treatment and prognosis. In this review, we attempted to provide a brief account of the influence of HBV genotype on the pathogenesis of HBV infection and summarize our current knowledge on the effects of HBV mutations in different regions on HBV-associated pathogenesis, with an emphasis on mutations in the preS/S proteins in immune evasion, occult HBV infection and hepatocellular carcinoma (HCC), mutations in polymerase in relation to drug resistance, mutations in HBV core and e antigen in immune evasion, chronicalization of infection and hepatitis B-related acute-on-chronic liver failure, and finally mutations in HBV x proteins in HCC.

Virological Characteristics of Acute Hepatitis B in Eastern India: Critical Differences with Chronic Infection

Hepatitis B Virus (HBV) manifests high genetic variability and is classifiable into ten genotypes (A-J). HBV infection can lead to variable clinical outcomes, ranging from self-limiting acute hepatitis to active chronic hepatitis, cirrhosis and hepatocellular carcinoma. The present study characterizes HBV strains circulating among patients with acute (AHB) and chronic HBV infection (CHB). Among a total of 653 HBsAg positive cases, 40 manifested acute infection. After sequencing the surface(S), basal core promoter/pre-core(BCP/PC) and the X gene regions, phylogenetic tree was constructed using MEGA4 by neighbor-joining method. Statistical robustness was established with bootstrap analysis. Nucleotide diversity was determined by Shannon entropy per site using the Entropy program of the Los Alamos National Laboratories. Analyses of acute patients revealed that HBV/D2 is the major circulating sub-genotype and commonly associated with sexual promiscuity and the age group between15-30 years. Comparison of AHB and CHB patients revealed that HBeAg positivity, ALT levels and genotype D were significantly high in AHB, whereas CHB patients were predominantly male, had a high viral load, and were commonly associated with genotype C. The frequencies of mutations in the S, BCP/PC, and X gene were low in AHB as compared to CHB. Drug resistant mutations were not detectable in the polymerase gene of AHB. Average nucleotide diversity in AHB was considerably low as compared to CHB. Further, the highest average ΔH (average difference in entropy between chronic and acute infection) was observed in the BCP/PC region implying that this region was most vulnerable to mutations upon HBV persistence, especially in case of genotype C. Additionally, among all substitutions, the A1762T and G1764A BCP mutations were the strongest indicators of chronicity. In conclusion, the study exhibits a general portrait of HBV strains circulating among acute hepatitis B patients in Eastern India and their intricate differences with chronic patients which should be useful from the clinical point of view.

Genomic Diversity of Hepatitis B Virus Infection Associated With Fulminant Hepatitis B Development

CONTEXT

After five decades of Hepatitis B Virus (HBV) vaccine discovery, HBV is still a major public health problem. Due to the high genetic diversity of HBV and selective pressure of the host immune system, intra-host evolution of this virus in different clinical manifestations is a hot topic of research. HBV infection causes a range of clinical manifestations from acute to chronic infection, cirrhosis and hepatocellular carcinoma. Among all forms of HBV infection manifestations, fulminant hepatitis B infection possesses the highest fatality rate. Almost 1% of the acutely infected patients develop fulminant hepatitis B, in which the mortality rate is around 70%.

EVIDENCE ACQUISITION

All published papers deposited in Genbank, on the topic of fulminant hepatitis were reviewed and their virological aspects were investigated. In this review, we highlight the genomic diversity of HBV reported from patients with fulminant HBV infection.

RESULTS

The most commonly detected diversities affect regulatory motifs of HBV in the core and S region, indicating that these alterations may convert the virus to an aggressive strain. Moreover, mutations at T-cell and B-cell epitopes located in pre-S1 and pre-S2 proteins may lead to an immune evasion of the virus, likely favoring a more severe clinical course of infection. Furthermore, point and frame shift mutations in the core region increase the viral replication of HBV and help virus to evade from immune system and guarantee its persistence.

CONCLUSIONS

Fulminant hepatitis B is associated with distinct mutational patterns of HBV, underlining that genomic diversity of the virus is an important factor determining its pathogenicity.

Genotypes and viral variants in chronic hepatitis B: A review of epidemiology and clinical relevance

The Hepatitis B Virus (HBV) has a worldwide distribution and is endemic in many populations. It is constantly evolving and 10 genotypic strains have been identified with varying prevalences in different geographic regions. Numerous stable mutations in the core gene and in the surface gene of the HBV have also been identified in untreated HBV populations. The genotypes and viral variants have been associated with certain clinical features of HBV related liver disease and Hepatocellular carcinoma. For example Genotype C is associated with later hepatitis B e antigen (HBeAg) seroconversion, and more advanced liver disease. Genotype A is associated with a greater risk of progression to chronicity in adult acquired HBV infections. Genotype D is particularly associated with the precore mutation and HBeAg negative chronic hepatitis B (CHB). The genotypes prevalent in parts of West Africa, Central and South America, E, F and H respectively, are less well studied. Viral variants especially the Basal Core Promotor mutation is associated with increased risk of fibrosis and cancer of the liver. Although not currently part of routine clinical care, evaluation of genotype and viral variants may provide useful adjunctive information in predicting risk about liver related morbidity in patients with CHB.

Epidemiology of HBV subgenotypes D

The natural history of hepatitis B virus infection is not uniform and affected from several factors including, HBV genotype. Genotype D is a widely distributed genotype. Among genotype D, several subgenotypes differentiate epidemiologically and probably clinically. D1 is predominant in Middle East and North Africa, and characterized by early HBeAg seroconversion and low viral load. D2 is seen in Albania, Turkey, Brazil, western India, Lebanon, and Serbia. D3 was reported from Serbia, western India, and Indonesia. It is a predominant subgenotype in injection drug use-related acute HBV infections in Europe and Canada. D4 is relatively rare and reported from Haiti, Russia and Baltic region, Brazil, Kenya, Morocco and Rwanda. Subgenotype D5 seems to be common in Eastern India. D6 has been reported as a rare subgenotype from Indonesia, Kenya, Russia and Baltic region. D7 is the main genotype in Morocco and Tunisia. D8 and D9 are recently described subgenotypes and reported from Niger and India, respectively. Subgenotypes of genotype D may have clinical and/or viral differences. More subgenotype studies are required to conclude on subgenotype and its clinical/viral characteristics.