Impact of hepatitis B virus genotype F on in vitro diagnosis: detection efficiency of HBsAg from Amerindian subgenotypes F1b and F4

Contemporary and historical human migration patterns shape hepatitis B virus diversity

Infection by hepatitis B virus (HBV) is responsible for approximately 296 million chronic cases of hepatitis B, and roughly 880,000 deaths annually. The global burden of HBV is distributed unevenly, largely owing to the heterogeneous geographic distribution of its subtypes, each of which demonstrates different severity and responsiveness to antiviral therapy. It is therefore crucial to the global public health response to HBV that the spatiotemporal spread of each genotype is well characterized. In this study, we describe a collection of 133 newly sequenced HBV strains from recent African immigrants upon their arrival in Belgium. We incorporate these sequences-all of which we determine to come from genotypes A, D, and E-into a large-scale phylogeographic study with genomes sampled across the globe. We focus on investigating the spatio-temporal processes shaping the evolutionary history of the three genotypes we observe. We incorporate several recently published ancient HBV genomes for genotypes A and D to aid our analysis. We show that different spatio-temporal processes underlie the A, D, and E genotypes with the former two having originated in southeastern Asia, after which they spread across the world. The HBV E genotype is estimated to have originated in Africa, after which it spread to Europe and the Americas. Our results highlight the use of phylogeographic reconstruction as a tool to understand the recent spatiotemporal dynamics of HBV, and highlight the importance of supporting vulnerable populations in accordance with the needs presented by specific HBV genotypes.

Recombinant HBsAg of the Wild-Type and the G145R Escape Mutant, included in the New Multivalent Vaccine against Hepatitis B Virus, Dramatically Differ in their Effects on Leukocytes from Healthy Donors In Vitro

Immune-escape hepatitis B virus (HBV) mutants play an important role in HBV spread. Recently, the multivalent vaccine Bubo®-Unigep has been developed to protect against both wild-type HBV and the most significant G145R mutant. Here, we compared the effects of recombinant HBsAg antigens, wild-type and mutated at G145R, both included in the new vaccine, on activation of a human high-density culture of peripheral blood mononuclear cells (PBMC) in vitro. The antigens were used either alone or in combination with phytohemagglutinin (PHA). None of the antigens alone affected the expression of CD40, HLA-DR or CD279. Wild-type HBsAg enhanced CD86 and CD69 expression, and induced TNF-α, IL-10, and IFN-γ, regardless of the anti-HBsAg status of donor. In the presence of PHA, wild-type HBsAg had no effect on either of the tested surface markers, but increased IFN-γ and IL-10 and inhibited IL-2. In contrast, the G145R mutant alone did not affect CD86 expression, it induced less CD69, and stimulated IL-2 along with lowering levels of TNF-α, IL-10, and IFN-γ. The G145R mutant also suppressed PHA-induced activation of CD69. The dramatic differences in the immune responses elicited by wild-type HBsAg and the G145R mutant HBsAg suggest distinct adaptive capabilities of the G145R mutant HBV.

Analysis of the complete genome of HBV genotypes F and H found in Brazil and Mexico using the next generation sequencing method

INTRODUCTION AND OBJECTIVES

Hepatitis B Virus is classified into ten different genotypes (A- J). Genotypes F and H cluster apart from others in phylogenetic trees and is particularly frequent in the Americas. The aim of this study was to sequence complete genomes of samples of HBV genotypes F and H from Brazil and Mexico using next generation sequencing (NGS) and to study relevant characteristics for the disease associated with this virus.

MATERIALS AND METHODS

Ninety plasma samples with detectable HBV DNA belonging to the F (n=59) and H (n=31) genotypes were submitted to amplification of the complete HBV genome by three different methologies. Data analysis was developed using bioinformatics tools for quality assurance and comprehensive coverage of the genome. Sequences were aligned with reference sequences for subgenotyping and detecting variants in relevant positions. A phylogenetical tree was constructed using Bayesian methods.

RESULTS

HBV genome of 31 samples were amplified and 18 of them were sequenced (HBV/F=16 and HBV/H=2). One genotype F sample was co-infected with the F1b and F3 subgenotypes, while the other samples were all F2a subgenotype. Two genotype H samples clustered with other Mexican sequences. The main variants observed were found in preS and S genes (7/18) and mutations in the precore/core region (11/18).

CONCLUSIONS

A NGS methodology was applied to F and H genotypes samples from Mexico and Brazil to fully characterize their sequences. This methodology will be relevant for clinical and epidemiological studies of hepatitis B in Latin America.

Hepatitis B virus genotypes prevalence in patients from hepatology services in Ceará, Brazil

INTRODUCTION

Hepatitis B virus (HBV) infection is a public health problem; therefore, we aimed to report HBV genotypes in Ceará, Brazil.

METHODS

A total of 103 HBsAg-positive samples were subjected to HBV genotyping and subgenotyping.

RESULTS

The following genetic compositions of samples were found: F-54% (F2-83.33%), A-40% (A1-65%), D-6%, C2-1%, E-1%, and G-1%.

CONCLUSIONS

Some genotypes are only prevalent in certain parts of the world; however, the State of Ceará is a hub for migration and has one of the most important liver transplantation centers in Brazil, which can explain the prevalence of the F genotype.

Hepatitis B virus American genotypes: Pathogenic variants ?

Hepatitis B virus (HBV) chronic infection is responsible for almost 900.000 deaths each year, due to cirrhosis or hepatocellular carcinoma (HCC). Ten HBV genotypes have been described (A-J). HBV genotype F and H circulate in America. HBV genotypes have been further classified in subgenotypes. There is a strong correlation between the genetic admixture of the American continent and the frequency of genotypes F or H: a high frequency of these genotypes is found in countries with a population with a higher ratio of Amerindian to African genetic admixture. The frequency of occult HBV infection in Amerindian communities from Latin America seems to be higher than the one found in other HBV-infected groups, but its association with American genotypes is unknown. There is growing evidence that some genotypes might be associated with a faster evolution to HCC. In particular, HBV genotype F has been implicated in a frequent and rapid progression to HCC. However, HBV genotype H has been associated to a less severe progression of disease. This study reviews the diversity and frequency of autochthonous HBV variants in the Americas and evaluates their association to severe progression of disease. Although no significant differences were found in the methylation pattern between different genotypes and subgenotypes of the American types, basal core promoter mutations might be more frequent in some subgenotypes, such as F1b and F2, than in other American subgenotypes or genotype H. F1b and probably F2 may be associated with a severe presentation of liver disease as opposed to a more benign course for subgenotype F4 and genotype H. Thus, preliminary evidence suggests that not all of the American variants are associated with a rapid progression to HCC.