Chronic Hepatitis B Virus Carriers Research Articles

Genome-Wide Association Study Identifies a New Locus at 7q21.13 Associated with Hepatitis B Virus-Related Hepatocellular Carcinoma.

Purpose: Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. In China, chronic hepatitis B virus (HBV) infection remains the major risk factor for HCC. In this study, we performed a genome-wide association study (GWAS) among Chinese populations to identify novel genetic loci contributing to susceptibility to HBV-related HCC.Experimental Design: GWAS scan is performed in a collection of 205 HBV-related HCC trios (each trio includes an affected proband and his/her both parents), and 355 chronic HBV carriers with HCC (cases) and 360 chronic HBV carriers without HCC (controls), followed by two rounds of replication studies totally consisting of 3,796 cases and 2,544 controls.Results: We identified a novel association signal within the CDK14 gene at 7q21.13 (index rs10272859, OR = 1.28, P = 9.46 × 10-10). Furthermore, we observed that the at-risk rs10272859[G] allele was significantly associated with higher mRNA expression levels of CDK14 in liver tissues. Chromosome conformation capture assays in liver cells confirmed that a physical interaction exists between the promoter region of CDK14 and the risk-associated SNPs in strong linkage disequilibrium with the index rs10272859 at 7q21.13. This index rs10272859 also showed significant association with the survival of HCC patients.Conclusions: Our findings highlight a novel locus at 7q21.13 conferring both susceptibility and prognosis to HBV-related HCC, and suggest the CDK14 gene to be the functional target of the 7q21.13 locus. Clin Cancer Res; 24(4); 906-15. ©2017 AACR.

How to control highly endemic hepatitis B in Asia.

Chronic hepatitis B virus (HBV) infection is an enormous economic and social burden. Asian countries such as Vietnam, Mongolia, Laos, China, the Philippines, South Korea, Singapore and Cambodia have high or high-intermediate HBsAg prevalence. Most of the chronic HBV carriers in this region acquire their infection during early childhood or through mother-to-child transmission (MTCT). Asia has been highly successful in controlling HBV in the last 2 decades. For example, China has adopted a comprehensive strategy to control HBV and has offered universal HBV vaccination to infants since 1992. With increasing coverage and a timely birth dose of the HBV vaccine, the prevalence of HBsAg in that general population decreased from 9.75% in 1992 to 7.18% in 2006. The prevalence of HBsAg in the population <30years old decreased from 10.1% in 1992 to 2.6% in 2014. In addition, passive and active immunization has been increased and has successfully interrupted MTCT in recent years. Recent studies in China show that maternal antiviral therapy in the late trimesters of pregnancy could further reduce MTCT in mothers with a high viral load. First-line treatments such as entecavir and tenofovir as well as pegylated interferon alpha are recommended in Chinese guidelines and are on the Basic Medical Insurance reimbursement list. Increased awareness, access to and affordability of antiviral therapy will reduce HBV-related morbidity and mortality. The combined efforts of the government, the medical community, industry, civil society and the public should eliminate hepatitis B as a public threat by 2030.

Hepatitis B reactivation among 1962 patients with hematological malignancy in Taiwan

BackgroundThe risk of Hepatitis B virus (HBV) reactivation in patients with different hematological malignancy except lymphoma were rarely known before.MethodsA total of 1962 patients with hematological malignancy were enrolled and followed-up at the National Taiwan University Hospital between 2008 and 2013. The clinical characteristics, HBV serology, and laboratory data were retrospectively reviewed and analyzed.ResultsA total of 1962 patients comprising 1048 men and 914 women were studied. The median age of the patients was 55 years (range, 15–97 years). Chronic HBV carriage was documented at diagnosis of hematological malignancy in 286 (14.6%) patients. A total of 171 (59.8%) of the 286 HBV carriers received primary prophylaxis with anti-HBV agents. Of the HBV carriers, 97 (33.9%) developed hepatitis B reactivation during or after chemotherapy, including 59 patients who had discontinued antiviral therapy. The incidence of hepatitis B reactivation among patients with hematological malignancy and HBV carriage was 10.4 per 100 person–years. A multivariate analysis revealed hepatocellular carcinoma (p < 0.001) and antiviral prophylaxis use (p < 0.001) were independent risk factors of HBV reactivation in HBV carriers. Of the 1676 patients with initial negative hepatitis B surface antigen (HBsAg) counts, 41 (2.4%) experienced hepatitis B reactivation, reverse seroconversion of HBsAg, and lost their protective hepatitis B surface antibody (anti-HBs). A multivariate analysis revealed that diabetes mellitus (p = 0.005, odds ratio (OR): 0.218, 95% confidence interval (CI): 0.076–0.629), allogeneic transplantation (p = 0.013, OR: 0.182, 95% CI: 0.047–0.701), liver cirrhosis (p < 0.001, OR: 0.002, 95% CI: 0–0.047), low anti-HBs titers (p = 0.016, OR: 0.020, 95% CI: 0.001–0.480), and positive hepatitis B core antibody (p = 0.013, OR: 0.070, 95% CI: 0.009–0.571) were independent risk factors of positive seroconversion of HBsAg in patients with hematological malignancy.ConclusionsThe incidence of HBV reactivation among the patients with varying subtypes of hematological malignancy is similar. Prophylaxis with anti-HBV agents critically reduced the risk of hepatitis B reactivation.

Decreased CD122 on CD56dim NK associated with its impairment in asymptomatic chronic HBV carriers with high levels of HBV DNA, HBsAg and HBeAg

AimsNK cells play important roles in inhibiting HBV replication and preventing HBV infection. However, NK-cell dysfunction has not been fully studied in asymptomatic chronic HBV carriers (ASC). This study aims to assess decreased expression of CD122 associated with impaired NK cells and the restoration of NK cells with IL-2 and IL-15 stimulation. Main methodsThe experiments were performed by flow cytometer, cytotoxicity assay, ELISA and western blotting. Key findingsThe reduced CD122 on CD56+ NK cells and CD56dim NK cells is associated with high levels of HBV DNA, HBsAg or HBeAg in ASCs, in which CD56dim NK-cell impairment is observed. Moreover, decreased IFN-γ and degranulation and low cytotoxicity by CD56dim NK cells after CD122 blockade were revealed. IL-2 and/or IL-15 can restore impaired CD56dim NK cells, together with increased p-STAT5, which can be reversed by CD122 blockade. Additionally, IL-2 or IL-15 can enhance IFN-α2-activated CD56dim NK-cell immune responses via up-regulating interferon alpha and beta receptor subunit 2 (IFNAR2). SignificanceDown-regulated CD122 on CD56dim NK cell in ASCs with massive viral antigens and high viremia is associated with its impairment, which can be restored by IL-2 and/or IL-15, or combined with IFN-α2.

Hepatitis B virus lymphotropism: emerging details and challenges

The hepatitis B virus (HBV) is predominantly a hepatotropic virus but also infects cells of the lymphatic system. HBV genomes (DNA, messenger (m)RNA, covalently closed circular (ccc) DNA) and proteins have been found in extrahepatic sites such as peripheral blood mononuclear cells (PBMC), lymph nodes, spleen, bone marrow and cerebrospinal fluid. HBV entry into hepatocytes occurs by binding of the HBV preS1 surface protein to its specific receptor, the bile acid transporter, sodium taurocholate co-transporting polypeptide (NTCP). Although the mechanism of HBV entry into lymphatic cells is unknown, the pre S1 encoded surface protein is thought to be involved. Extrahepatic HBV infection has been studied in both chronic HBV (CHB) and in occult HBV infection (OBI). Studies have shown that HBV genomes are present in different PBMC subsets from chronically infected carriers. Unique HBV variants have been found in PBMC compared to plasma or liver in both nucleos(t)ide analogue (NA) treated and untreated CHB carriers, suggesting replication and compartment specific evolution of HBV. In HBV coinfection, HBV genomes were found in PBMC from hepatitis C virus (HCV), human immunodeficiency virus (HIV) and hepatitis delta virus (HDV) co-infected individuals. Moreover, during pregnancy, the trans placental passage of HBV infected PBMC from highly viremic mothers to infants is one of the postulated means of vertical transmission of HBV. Taken together, HBV infection in extrahepatic sites (i.e., PBMC) is implicated in multiple facets of HBV pathogenesis such as persistence, viral evolution and vertical transmission.

Vaccine Therapy in Chronic Hepatitis B Carriers: A Randomised Double-Blind Controlled Trial

Introduction: Chronic carriers of Hepatitis B Virus (HBV) are persistent sources of the virus and may transmit HBV to healthy individuals. Aim: This study was conducted to assess therapeutic effects of HBV vaccine on Chronic HBV Carriers (CHC). Methods and Materials: This clinical trial was conducted on CHCs aged 20-65 years, randomly allocated into four groups. Group 1 (control) did not receive vaccine. Group 2, 3 and 4 (vaccine groups) received different doses of HBV vaccine. HBV viral load (IU/mL) was assessed at baseline and two months after the last dose of HBV vaccine. Reduction or elimination of HBV viral load was considered as positive response. Absolute Response Rates (ARR) was calculated for each group. Subgroup analysis was done on subjects with baseline viral load of <100,000 and negative HBeAb. Relative Response Rates (RRR) was defined as ARR in vaccine group divided by that of control. RRRs were calculated for total participants (overall RRR) and the above-mentioned subgroup of subjects (subgroup RRR). Results: In total, 97 CHCs were recruited. No adverse reaction was reported. There was no significant difference in ARRs between study groups (p-value=0.09). An overall RRR of 0.78 and a subgroup RRR of 1.18 has been reported. A 50 increase was found in the RRR in subgroups of subjects with baseline viral load of <100,000 and negative HBeAb compared to the overall RRR. Conclusion: It may be worth future studies to assess the therapeutic effects of HBV vaccine. © 2018, Journal of Clinical and Diagnostic Research. All rights reserved.

The Influence of B and T Lymphocyte Attenuator Genetic Variants on Susceptibility to Chronic Hepatitis B Virus Infection

Background/Aims: B and T lymphocyte attenuator (BTLA) is an immune inhibitory receptor involved in the pathogenesis of chronic viral infections. Little is known about the effects of BTLA gene polymorphisms on chronic hepatitis B virus (HBV) infections. In this study, we investigated whether the polymorphisms of BTLA are associated with the progression of chronic HBV infection. Methods: A total of 382 chronic HBV carriers and 170 healthy individuals in the same region were recruited for this study. The chronic HBV carriers were divided into three groups: asymptomatic HBV carriers (ASC), moderate chronic hepatitis B group (MCHB), and severe chronic hepatitis B group (SCHB). Two BTLA functional single nucleotide polymorphisms (SNPs; rs76844316 and rs9288952) were genotyped by polymerase chain reaction and sequenced directly. Results: The results showed that the frequency of the G allele of rs76844316 was significantly lower in the SCHB group than in the other three groups. Subjects bearing at least one G allele (TG or GG genotype) at rs76844316 had decreased susceptibility to severe chronic hepatitis B compared with those bearing the TT genotype. Haplotype analysis of the two SNPs revealed that the frequency of the G-G haplotype was significantly lower in SCHB patients than in controls. Moreover, in the SCHB group, patients carrying the G allele of rs76844316 tended to have lower ALT levels than those without it. Conclusion: Our findings suggest that the genetic variants of rs76844316 in BTLA influence the susceptibility to severe chronic hepatitis B and might play a protective role against the progression of chronic hepatitis B.

FABP1 Polymorphisms Contribute to Hepatocellular Carcinoma Susceptibility in Chinese Population with Liver Cirrhosis: A Case-Control Study.

Purpose: Single nucleotide variations in the liver fatty acid binding protein (L-FABP, FABP1) gene lead to changes in cellular signaling pathways and lipid metabolism. FABP1 polymorphisms were associated with some liver diseases, like steatotic hepatocellular carcinoma. However, the association between FABP1 rs1545224 and rs2241883 polymorphisms and hepatitis B virus-related liver cirrhosis (LC) and hepatocellular carcinoma (HCC) has not been reported. We performed this study to explore their relationship.Methods: One thousand individuals (250 healthy controls, 250 chronic HBV (CHB), 250 LC, and 250 HCC patients) were recruited. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were applied to assess the difference in allele and genotype frequencies. Cochran-Armitage trend test was used to evaluate the cumulative effect. Significant difference would be defined when the P value was less than 0.05.Results: The distribution of rs1545224 GG, AG and AA genotypes in healthy controls or CHB carriers was not significant when compared to LC or HCC patients (P>0.05). LC patients carrying at least one A allele are more likely to develop HCC in contrast with those with G allele (P<0.05). After adjustment for confounders, meaningful results were only seen in the comparison between rs1545224 AG+AA genotype carriers and GG genotype carriers among the LC patients (P<0.05). Rs2241883 polymorphism did not influence the risk of developing LC or HCC in healthy and CHB individuals, nor did it influence the risk of HCC in LC patients (P>0.05).Conclusions: Taken together, FABP1 rs1545224 polymorphism might increase HCC risk in LC patients, indicating that FABP1 rs1545224 polymorphism may be related to the process of developing HCC in Chinese patients with LC.

Nanovaccine for immunotherapy and reduced hepatitis-B virus in humanized model

Chronic Hepatitis B Virus (HBV) infections are severe with weak antiviral immune responses. The lack of an appropriate small animal model for chronic hepatitis, a major hurdle for studying the immunotolerance and immunopathogenesis induced by hepatitis B viral (HBV) infection. In this study, for enhancing the antibody production efficiency the prepared polymeric HBsAg-loaded nanoparticles (nanovaccine) will be tested in immune-deficit mice, which suffer from chronic Hepatitis B virus. Vaccination of Balb/c mice by this prepared nanoparticles that were engrafted with peripheral blood mononuclear cells (PBMCs), which was already lethally irradiated and transplanted by the bone marrow of NOD (knockout mice) mice. In the present study, after the vaccination detected the high frequencies of immunoglobulin G (IgG)-secreting B cells and mitogen-responsive interferon-Y (IFN-Y) secreting T cells in serum, determined by specific ELISA technique. During the entire observation period, unvaccinated animals showed lower concentration of specific IgG secreting B cells and IFN-Y secreting T cells found in comparison to vaccinated mice group. Chronic HBV carrier PBMCs transplanted into the chimera failed to produce antigen and increased the antibodies production due to vaccination. Furthermore, another advantage was that the viral gene expression and viral DNA replication was no longer observed in vaccinated group. This prepared nanovaccine formulations is better for the cure of Hepatitis B viral infection carrier. Therefore, specific memory responses were elicited by vaccination with Hepatitis B virus surface (HBsAg) antigen of chimeric mice transplanted with PBMCs derived from HBV donors.

Mutations in Hepatitis B virus polymerase gene/partial surface gene among Chronic HBV carriers as markers for anti-viral drug resistance and escape mutants

Mutations in Hepatitis B virus polymerase gene/partial surface gene among Chronic HBV carriers as markers for anti-viral drug resistance and escape mutants

Association of ACYP2 and MPHOSPH6 genetic polymorphisms with the risk of hepatocellular carcinoma in chronic hepatitis B virus carriers.

Hepatocellular carcinoma (HCC) is the dominant histologic type of primary liver cancer, and hepatitis B virus (HBV) infection is one of the major causes of HCC in the chronic HBV. Our study was investigated the association between the polymorphisms of ACYP2 and MPHOSPH6 genes and the risk of HCC induced by HBV infection. A total of 490 subjects were divided into two groups: 248 HBV patients with HCC (Case group), and 242 HBV patients without HCC (Control group). Unconditional logistic regression analysis was used to evaluate the association. The genetic association analysis revealed variant of rs12621038 in ACYP2 gene had a significant association with increasing the risk of HBV-induced HCC based on the genotype, dominant and additive model (P<0.05). Moreover, our results also showed that minor allele “C” of rs3751862 was prevalent in cases than controls (P<0.05), and rs3751862 significantly increased the risk of HCC in chronic HBV carriers under genotype and dominant model (P<0.05). In addition, the haplotype “T-G-G” in MPHOSPH6 showed a harmful factor for the HBV-induced HCC (P<0.05). The results suggested that ACYP2 and MPHOSPH6 as the plausible candidate genes may predict the risk of HCC after chronic HBV infection in Chinese Han population, and further investigations in studies with a larger sample size and other races are needed to validate our findings. These data provide a theoretical foundation for future studies of this correlation between the polymorphisms of ACYP2 and MPHOSPH6 genes and the HCC in chronic HBV carriers.

Prevalence of chronic hepatitis B virus infection and infrastructure for its diagnosis in Madagascar: implication for the WHO\u2019s elimination strategy

BackgroundWHO developed a global strategy to eliminate hepatitis B by 2030 and set target to treat 80% of people with chronic hepatitis B virus (HBV) infection eligible for antiviral treatment. As a first step to achieve this goal, it is essential to conduct a situation analysis that is fundamental to designing national hepatitis plans. We therefore estimated the prevalence of chronic HBV infection, and described the existing infrastructure for HBV diagnosis in Madagascar.MethodsWe conducted a stratified multi-stage serosurvey of hepatitis B surface antigen (HBsAg) in adults aged ≥18 years using 28 sentinel surveillance sites located throughout the country. We obtained the list of facilities performing HBV testing from the Ministry of Health, and contacted the person responsible at each facility.ResultsA total of 1778 adults were recruited from the 28 study areas. The overall weighted seroprevalence of HBsAg was 6.9% (95% CI: 5.6–8.6). Populations with a low socio-economic status and those living in rural areas had a significantly higher seroprevalence of HBsAg. The ratio of facilities equipped to perform HBsAg tests per 100,000 inhabitants was 1.02 in the capital city of Antananarivo and 0.21 outside the capital. There were no facilities with the capacity to perform HBV DNA testing or transient elastography to measure liver fibrosis. There are only five hepatologists in Madagascar.ConclusionMadagascar has a high-intermediate level of endemicity for HBV infection with a severely limited capacity for its diagnosis and treatment. Higher HBsAg prevalence in rural or underprivileged populations underlines the importance of a public health approach to decentralize the management of chronic HBV carriers in Madagascar by using simple and low-cost diagnostic tools.

Compartmental HBV evolution and replication in liver and extrahepatic sites after nucleos/tide analogue therapy in chronic hepatitis B carriers

BackgroundHepatitis B virus (HBV) variants are associated with nucleos/tide analogue (NA) response and liver disease but it is unknown whether NA influences extrahepatic HBV persistence. ObjectivesTo investigate HBV replication and genetic evolution in hepatic and extrahepatic sites of chronic hepatitis B (CHB) before and after NA therapy. Study DesignA total of 13 paired plasma, peripheral blood mononuclear cells (PBMC), were collected from chronic HBV carriers at baseline and after a median 53 weeks NA therapy as well as liver biopsy (N=7 baseline, N=5 follow-up). HBV covalently closed circular DNA (cccDNA) and messenger (m) RNA in liver and PBMC were analyzed. HBV polymerase (P)/surface (S), basal core promoter (BCP)/pre-core (PC)/C gene clonal sequencing was done in plasma, peripheral blood mononuclear cells (PBMC), and liver. ResultsCompare to baseline, at ∼53 weeks follow-up, there was no significant change in HBV cccDNA levels in liver (0.2–0.08 copies/hepatocyte, p>0.05) or in PBMC 0.003–0.02 copies/PBMC, p>0.05), and HBV mRNA remained detectable in both sites. At baseline, BCP variants were higher in PBMC vs. liver and plasma. After therapy, drug resistant (DR) and immune escape (IE) variants increased in liver but IE and PC variants were more frequent in PBMC. HBV P/S diversity was significantly higher in PBMC compared to plasma. ConclusionContinuous HBV replication occurs in liver and PBMC and shows compartmentalized evolution under selective pressure of potent NA therapy.

Cloning of anti-HBsAg single-chain variable fragments from hybridoma cells for one-step ELISA

ABSTRACTHepatitis B virus (HBV) infection is a worldwide health problem. More than 400 million people are chronic HBV carriers in the world. Infected individuals are at a high risk of developing liver cirrhosis and hepatocellular carcinoma as the main consequences of HBV. The discoveries of fast diagnostic systems and new therapeutic applications are crucial in the fight against viral hepatitis. In this paper we present the generation of a single-chain variable fragment (scFv) from a mouse monoclonal antibody specific to the HBV surface antigen (HBsAg) and demonstrate its expression as a bacterial alkaline phosphatase (AP) fusion protein. In this study, we constructed scFvs from hybridoma cells expressing HBsAg-specific antibody using phage display technology and expressed them in Escherichia coli. The anti-HBsAg scFvs were inserted into pQE-2 vector to produce scFv antibody genetically fused to bacterial AP. Reproducibility of the recombinant HBsAg-scFv fusion protein was tested using Enzyme-linked Immunosorbent Assay (ELISA). Present preliminary findings indicate that the anti-HBsAg-scFv AP conjugate could be further used for the development of one-step ELISA for the detection of HBV.

Hepatitis Delta Virus: Replication Strategy and Upcoming Therapeutic Options for a Neglected Human Pathogen.

The human Hepatitis Delta Virus (HDV) is unique among all viral pathogens. Encoding only one protein (Hepatitis Delta Antigen; HDAg) within its viroid-like self-complementary RNA, HDV constitutes the smallest known virus in the animal kingdom. To disseminate in its host, HDV depends on a helper virus, the human Hepatitis B virus (HBV), which provides the envelope proteins required for HDV assembly. HDV affects an estimated 15–20 million out of the 240 million chronic HBV-carriers and disperses unequally in disparate geographical regions of the world. The disease it causes (chronic Hepatitis D) presents as the most severe form of viral hepatitis, leading to accelerated progression of liver dysfunction including cirrhosis and hepatocellular carcinoma and a high mortality rate. The lack of approved drugs interfering with specific steps of HDV replication poses a high burden for gaining insights into the molecular biology of the virus and, consequently, the development of specific novel medications that resiliently control HDV replication or, in the best case, functionally cure HDV infection or HBV/HDV co-infection. This review summarizes our current knowledge of HBV molecular biology, presents an update on novel cell culture and animal models to study the virus and provides updates on the clinical development of the three developmental drugs Lonafarnib, REP2139-Ca and Myrcludex B.

Cytotoxic T lymphocytes and CD4 epitope mutations in the pre-core/core region of hepatitis B virus in chronic hepatitis B carriers in Northeast Iran

Hepatitis B virus (HBV) is vulnerable to many various mutations. Those within epitopes recognized by sensitized T cells may influence the re-emergence of the virus. This study was designed to investigate the mutation in immune epitope regions of HBV pre-core/core among chronic HBV patients of Golestan province, Northeast Iran. In 120 chronic HBV carriers, HBV DNA was extracted from blood plasma samples and PCR was done using specific primers. Direct sequencing and alignment of the pre-core/core region were applied using reference sequence from Gene Bank database (Accession Number AB033559). The study showed 27 inferred amino acid substitutions, 9 of which (33.3%) were in CD4 and 2 (7.4%) in cytotoxic T lymphocytes' (CTL) epitopes and 16 other mutations (59.2%) were observed in other regions. CTL escape mutations were not commonly observed in pre-core/core sequences of chronic HBV carriers in the locale of study. It can be concluded that most of the inferred amino acid substitutions occur in different immune epitopes other than CTL and CD4.

Seroprevalence and risk factors of hepatitis B virus among blood donors in district Charsadda Khyber Pakhtunkhwa Pakistan

Hepatitis B Virus (HBV) is a serious worldwide public health issue both in underdeveloped and developed countries. About two billion individuals were infected by HBV globally, of which 400 million were chronic HBV carrier. The aim of this retrospective study was to investigate the seroprevalence and some possible risk factors of hepatitis B virus infection among male blood donors in district Charsadda, Khyber Pakhtunkhwa Pakistan. A total of 460 male blood donors with age range 15-55 years were screened for HBsAg by Immunochromatographic technique (ICT) and 3rd generation enzyme-linked immunosorbent assay (ELISA). Out of 460 samples, 11(2.39%) were found positive for HBsAg by ICT, and 13(2.82%) were HBsAg positive by ELISA. The mean seroprevalence of HBV from both ICT and ELISA was 2.60%. The highest seroprevalence (46.15%) was observed among the donor groups with age range of 21-30 years followed by (30.76%) among 15-20 years, (15.38%) among 31-40 years and the lowest seroprevalence (7.69%) among 41-55 years. Blood transfusion (30.76%) was the most apparent influencing risk factor for HBV followed by dental treatment (23.07%), Sexual partner positive for HBV infection (15.38%), surgery and shave by the barbers (7.69%) for each and unknown reason (15.38%). Keywords: Hepatitis B virus; ELISA; ICT; Risk factors; Blood donors http://dx.doi.org/10.19045/bspab.2017.60070

Alternative splicing of hepatitis B virus: A novel virus/host interaction altering liver immunity

Hepatitis B virus (HBV) RNA can undergo alternative splicing, but the relevance of this post-transcriptional regulation remains elusive. The mechanism of HBV alternative splicing regulation and its impact on liver pathogenesis were investigated. HBV RNA-interacting proteins were identified by RNA pull-down, combined with mass spectrometry analysis. HBV splicing regulation was investigated in chemically and surgically induced liver damage, in whole HBV genome transgenic mice and in hepatoma cells. Viral and endogenous gene expression were quantified by quantitative reverse transcription polymerase chain reaction, Western blot and enzyme-linked immunosorbent assay. Resident liver immune cells were studied by fluorescence-activated cell sorting. HBV pregenomic RNA-interacting proteins were identified and 15% were directly related to the splicing machinery. Expression of these splicing factors was modulated in HBV transgenic mice with liver injuries and contributed to an increase of the HBV spliced RNA encoding for HBV splicing-generated protein (HBSP). HBSP transgenic mice with chemically induced liver fibrosis exhibited attenuated hepatic damage. The protective effect of HBSP resulted from a decrease of inflammatory monocyte/macrophage recruitment through downregulation of C-C motif chemokine ligand 2 (CCL2) expression in hepatocytes. In human hepatoma cells, the ability of HBSP to control CCL2 expression was confirmed and maintained in a whole HBV context. Finally, viral spliced RNA detection related to a decrease of CCL2 expression in the livers of HBV chronic carriers underscored this mechanism. The microenvironment, modified by liver injury, increased HBSP RNA expression through splicing factor regulation, which in turn controlled hepatocyte chemokine synthesis. This feedback mechanism provides a novel insight into liver immunopathogenesis during HBV infection. Lay summary: Hepatitis B virus persists for decades in the liver of chronically infected patients. Immune escape is one of the main mechanisms developed by this virus to survive. Our study highlights how the crosstalk between virus and liver infected cells may contribute to this immune escape.

Aflatoxin B1 exposure increases the risk of cirrhosis and hepatocellular carcinoma in chronic hepatitis B virus carriers.

The relation between aflatoxin B1 (AFB1 ) and cirrhosis in chronic carriers of hepatitis B virus (HBV) remains inconclusive. This case-control study nested in a large community-based cohort aimed to assess the effect of AFB1 exposure on cirrhosis and HCC in chronic HBV carriers. Serum AFB1 -albumin adduct levels at study entry were measured in 232 cirrhosis cases, 262 HCC cases and 577 controls. Multivariate-adjusted odds ratios (aORs) and 95% confidence intervals (95% CIs) were estimated using logistic regression. Among all chronic HBV carriers, the time intervals between study entry and diagnosis of HCC, cirrhosis, cirrhotic HCC, and non-cirrhotic HCC were all significantly (p < 0.0001) shorter in participants with high serum levels of AFB1 -albumin adducts than those with low/undetectable levels. There were significant dose-response relations with serum AFB1 -albumin adduct level at study entry for cirrhosis (p-trend = 0.0001) and cirrhotic HCC (p-trend < 0.0001) newly diagnosed within 9 years after entry as well as non-cirrhotic HCC (p-trend = 0.021) newly diagnosed within 4 years after entry. The aORs (95% CIs) for high versus undetectable serum AFB1 -albumin adduct levels were 2.45 (1.51-3.98) for cirrhosis (p = 0.0003), 5.47 (2.20-13.63) for cirrhotic HCC (p = 0.0003), and 5.39 (1.11-26.18) for non-cirrhotic (p = 0.0368) HCC, respectively. There remained a significant dose-response relation between serum AFB1 -albumin adduct level and HCC risk (p-trend = 0.0291) in cirrhosis patients, showing an aOR (95% CI) of 3.04 (1.11-8.30) for high versus undetectable serum levels (p = 0.0299). It is concluded that AFB1 exposure may increase the risk of cirrhosis and HCC in a dose-response manner among chronic HBV carriers.

Distribution of HBV subgenotypes in Ribeirão Preto, Southeastern Brazil: a region with history of intense Italian immigration

Hepatitis B virus (HBV) is distributed worldwide, with geographical variations regarding prevalence of the different genotypes. The aim of this study was to determine the HBV genotypes and subgenotypes circulating in Southeast Brazil and compare the genetic sequences found with HBV sequences previously described in the world. Sequences from 166 chronic HBV carriers were analyzed using the fragment constituted by 1306 base pairs comprising surface and polymerase regions of the HBV genome. The sequences obtained were submitted to phylogenetic analysis. HBV subgenotypes A1, A2, D1-D4, F2a, and F4 were found. HBV genotype D was the most frequent, found in 99 patients (58.4%). Within this group, subgenotype D3 was the most prevalent, in 73 patients (42.9%). HBV genotype A was identified in 58 (36%) patients, subgenotype A1, in 48 (29.8%) subjects. Genotype F was identified in 9 (5.4%). According to the phylogenetic analysis, the sequences found were grouped with sequences from Europe, Asia and Middle East (subgenotypes D1, D2, D3) and sequences from Latin America and Africa (subgenotype A1). HBV D3 grouped in different clusters inside D3 clade, several of them with sequences isolated in Italy. We also identified eight families whose relatives were infected with the same HBV subgenotype, most with high similarity between sequences. In conclusion, the distribution of the HBV sequences obtained interweaved with sequences from other continents, corresponding to regions from where many immigrants came to this region, in accordance to the hypothesis that the HBV detected over there were brought during the colonization times.