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Complete Genome Sequencing of Occult Hepatitis B Virus in Hemodialysis Patients Reveals Subgenotype D2 and Immune Escape Mutations in Bangladesh.

Hepatitis B virus (HBV) remains a major global health concern, and occult HBV infection (OBI) presents significant diagnostic and clinical challenges, particularly among hemodialysis (HD) patients. This study is aimed at characterizing complete HBV genomes from maintenance HD patients with OBI in Bangladesh to elucidate genetic features, mutational patterns, and clinical implications. Serum samples from two HBsAg-negative HD patients were screened by ELISA and quantitative PCR. Viral DNA was amplified by PCR across four overlapping open reading frames (ORFs) and sequenced on the Illumina platform. Genome assembly, phylogenetic analysis, and mutational profiling were performed using reference datasets and bioinformatics tools. Antigenicity and hydrophilicity of HBsAg were predicted in silico. Both patients were anti-HBc and anti-HBs positive with high HBV DNA loads (2.29 × 1010 and 2.53 × 1010 copies/mL). Full-length genomes (3182 bp) were successfully sequenced and phylogenetic analysis showed both HBV genomes clustered within Genotype D, Subgenotype D2, and subtype ayw3, consistent with previously reported Bangladeshi HBV genomes. Comparative mutational analysis identified substitutions such as T1753C in the basal core promoter, C1845T in preC, and D144E within the "a" determinant of HBsAg, suggesting potential roles in vaccine escape, immune escape, and diagnostic failure. Several nonsynonymous mutations were also detected in polymerase, though none were potentially associated with antiviral resistance. Antigenicity and hydrophilicity profiles of HBsAg and its major hydrophilic region remained largely conserved. These findings demonstrate the persistence of OBI in HD patients and provide an initial indication of the need for genomic surveillance to monitor immune-escape mutations and improve HBV diagnostic strategies in endemic regions.

HBV genome sequencing

Global inequities in hepatitis B and C genomic surveillance revealed through an interactive data integration dashboard.

OBJECTIVES: To assess global disparities in hepatitis B virus (HBV) and hepatitis C virus (HCV) genomic surveillance and to develop an integrated platform that links genomic data with epidemiological burden. STUDY DESIGN: Retrospective observational analysis. METHODS: We reviewed existing viral genomic repositories to identify structural and analytical limitations. Subsequently, we integrated 10 996 HBV and 3533 HCV whole-genome sequences (WGS) from public databases with Global Burden of Disease (GBD) estimates to quantify inequities in genomic surveillance across countries and genotypes. Using these data, we developed the open-access Hepatitis Dashboard, incorporating >14 000 sequences from 141 countries with GBD metrics to evaluate representativeness and sequencing coverage relative to disease burden. RESULTS: Marked inequities in hepatitis genomic surveillance were identified. Despite increasing HBV- and HCV-associated mortality, virus sequence availability remains geographically and genotypically skewed-dominated by China and the United States, with substantial underrepresentation of HBV genotype E and HCV genotypes 5 and 8. Many high-endemic countries in Africa and the Western Pacific remain severely undersampled. We detected circulating antiviral drug-resistance mutations and developed a burden-adjusted sequencing coverage metric, revealing that several high-burden countries, including China, Nigeria and India, are among the least represented in global genomic datasets. Projections to 2030 indicate that neither HBV nor HCV are currently on track to meet WHO elimination targets. CONCLUSIONS: The Hepatitis Dashboard provides an integrated, continuously updated resource that links genomic and epidemiological data to quantify and visualise global surveillance gaps. This analysis highlights a critical disconnect between sequencing efforts and public health needs, which may limit the effectiveness of surveillance-informed strategies to support progress toward WHO 2030 elimination goals. By enabling burden-adjusted prioritisation and longitudinal tracking of genomic coverage, the platform supports evidence-based sampling strategies, equitable resource allocation, and monitoring of global progress toward hepatitis elimination.

Humans

Fatal Hepatitis B Reactivation in Absence of Antibody to Hepatitis B Core Antigen in a Lymphoma Patient.

Reactivations of hepatitis B virus (HBV) infection in severely immunocompromised patients with serological profiles of past hepatitis B are non-exceptional and potentially severe or fatal events. The preventive and pre-emptive detection of this serological status is compromised in the absence of antibodies to hepatitis B core antigen (anti-HBc), observed in a very small number of cases of HBV infection. Here, we describe the case of a patient with a serological profile indicating a HBV vaccination although the patient did not report previous vaccination, following lymphoma and chemotherapy including rituximab. This patient presented HBV reactivation with appearance of hepatitis B surface antigen (HBsAg) but without appearance of anti-HBc, suggesting the absence of detectable anti-HBc in this patient at the stage of past infection. Next-generation sequencing provided the complete HBV genome, showing the presence of a mutation in HBsAg associated with immune escape but without the detection of mutations in the core gene previously described as significantly associated with the absence of anti-HBc. Nonetheless, W28* pre-core mutation was found, which was reported to enhance replication capacity in case of weak immune responses and suspected to promote HBV reactivation in association with immune escape mutations. Overall, this case highlights that negativity of anti-HBc cannot definitely rule out past HBV infection and the risk of HBV reactivation in immunocompromised patients in the context of treatment of hemopathies, and that it is difficult to assess such a risk and to prevent or monitor HBV reactivation in patients with past HBV infection but no detectable anti-HBc.

Female

Next-Generation Sequencing Methods for Sensitive Hepatitis B Viral Genome Analysis: A European Study.

This multicentre study investigated the utility of next-generation sequencing (NGS) to detect and generate hepatitis B virus (HBV) genomes in samples of low viral load (from 0.2 to 6207 IU/mL). 23 HBV DNA-positive plasma samples of genotypes A-E and one HBV-negative control sample were assayed blindly via 9 established NGS methods from 6 European laboratories. Methods included untargeted metagenomics, pre-enrichment by probe-capture followed by Illumina sequencing, and HBV-specific PCR pre-amplification followed by sequencing with Nanopore or Illumina. Full HBV genomes were obtained only from samples with viral loads > 1000 IU/mL using probe-capture methods, > 200 IU/mL using PCR-Illumina methods, > 10 IU/mL using PCR-Nanopore methods, and in no samples using metagenomic methods. Contamination was observed in the negative control and samples with very low viral loads in PCR-based methods. Probe-capture and metagenomic methods detected additional viruses not routinely screened in blood donations, including polyomaviruses and herpesviruses; positive results were confirmed by PCR. In conclusion, NGS may delineate whole-genome sequences at low viral loads if supported by a PCR pre-amplification step. Probe-capture methods also reliably detect HBV without pre-amplification but show limited genome coverage for samples with low viral loads; they may additionally detect a wide range of blood-borne viruses.

Humans

Classification and sequencing of hepatitis D virus from a large cohort of chronically infected individuals paired with co-infecting hepatitis B virus sequencing: a genomic characterisation study.

BACKGROUND: The most severe form of viral hepatitis is caused by co-infection of hepatitis D virus (HDV) and hepatitis B virus (HBV). Phylogenetic analyses classify HBV and HDV into eight major genotypes: HBV GTA to GTH and HDV GT1 to GT8. Paired HBV and HDV sequencing data from participants with chronic hepatitis delta are scarce. We aimed to sequence and genotype HDV and HBV from a large cohort of participants from clinical studies and diverse countries of origin. METHODS: 407 participants with chronic hepatitis D from 24 countries were characterised (124 participants from MYR301 clinical trial, 93 from MYR204, 114 from MYR202, and an additional 76 participants from diverse geographical locations). HBV and HDV from participants were analysed using sequencing, enzyme immunoassay, or both to determine HBV and HDV genotypes. BLAST analysis and phylogenetics were used to determine HBV and HDV genotypes with reference sequence libraries. Bulevirtide treatment response (measured by HDV RNA decline and normalisation of alanine aminotransferase) was compared by genotype for MYR trial participants. FINDINGS: HDV sequencing assays were successful for 386 (95%) of 407 participants and HBV sequencing or serology-based HBV genotyping assays were successful for genotyping 395 (97%) participants. For individual genotypes, HBV GTD (336 [83%] participants) and HDV GT1 (364 [89%]) were the most prevalent. For paired HBV-HDV genotypes, HBV-HDV D/1 was most common (320 [79%] of 407) followed by A/1 (30 [7%]). Phylogenetic analyses of HDV full-genome sequences showed distinct clusters of sequences within HDV GT1, and four novel provisional HDV GT1 subgenotypes, HDV GT1fp to HDVGT1ip, were identified. For 218 MYR clinical trial participants, bulevirtide treatment response was similar across HDV GT1 subgenotypes (both established and newly identified). INTERPRETATION: Novel HDV subgenotypes identified in this study indicate a greater genetic diversity of HDV GT1 than previously recognised. This knowledge will be important for developing better diagnostics, and in understanding HDV genotype-specific biology and response to treatment. More extensive HDV sequencing from under-sampled regions, such as Africa, is needed to determine the true breadth of HDV sequence and genotype diversity. FUNDING: Gilead Sciences.

Hepatitis Delta Virus

Unraveling the Role of Mutations Outside the Basal Promoter and Precore Regions in the HBeAg-Negative Stage of Chronic Hepatitis B.

Hepatitis B e antigen (HBeAg) seroconversion is a crucial event in the natural history of chronic hepatitis B virus (HBV) infection, marked by a significant decrease in viral load and the emergence of mutations that suppress HBeAg expression. However, these mutations alone do not fully account for the reduction in viral load. This study investigated the biological features and pathogenic roles of mutations outside the basal core promoter (BCP) and precore regions during the HBeAg-negative stage of chronic infection. Full-length HBV genomes from HBeAg-positive (n = 180) and HBeAg-negative (n = 328) genotype D datasets were analyzed, revealing significantly higher genomic heterogeneity in HBeAg-negative sequences compared with HBeAg-positive genomes (50.4 ± 16.0 vs. 26.6 ± 10.5 nucleotide changes per genome). Twenty-six hotspot amino acid mutations associated with the HBeAg-negative stage were identified, with over half located in the Core region. Subsequently, full-length HBV genomes from six HBeAg-negative patient-derived serum samples were obtained by PCR amplification followed by Sanger sequencing. Infectious clones generated from these genomes, each carrying between 21 and 66 amino acid substitutions, were characterized, showing that mutations in this stage differentially affected viral fitness in vitro by up- or downregulating HBV-DNA levels (ranging from 0.2 to 5 times those of the wild-type isolate), modulating capsid assembly, and altering the expression, secretion, and subcellular localization of viral proteins. In conclusion, while mutations in the BCP and precore regions are the primary drivers of HBeAg seroconversion, mutations outside these regions significantly influence HBV biology and potentially contribute to viral pathogenicity, underscoring the complex interplay between host and virus during the HBeAg-negative stage of chronic infection.

Humans

Hepatitis B Virus-KMT2B Integration Drives Hepatic Oncogenic Processes in a Human Gene-edited Induced Pluripotent Stem Cells-derived Model.

BACKGROUND & AIMS: Hepatitis B virus (HBV)-DNA integration into the host genome contributes to hepatocellular carcinoma (HCC) development. KMT2B is the second most frequent locus of HBV-DNA integration in HCC; however, its role and function remain unclear. We aimed to clarify the impact of HBV-KMT2B integration in HCC development using a human genome-edited induced pluripotent stem cell (iPSCs) model. METHODS: Based on the genetic information on HBV-KMT2B integration in HCC, we determined its complete DNA sequence and transcript variants. To exclude the effect of other oncogenic mutations, we reproduced HBV integration in healthy donor iPSCs with an intact genome and analyzed its effects using iPSC-derived hepatic progenitor cells (HPCs) and hepatocytes (iPS-Heps). RESULTS: The reproduced HBV-KMT2B integration significantly upregulated the proliferation of hepatic cells. Comprehensive transcriptional and epigenetic analyses revealed enhanced expression of cell cycle-related genes in hepatic cells with HBV-KMT2B integration based on perturbation of histone 3 lysine 4 tri-methylation (H3K4me3), mimicking that in the original HCC sample. Long-read RNA-sequence detected the common KMT2B transcript variants in the HCC sample and HPCs. Overexpression of the truncated variant significantly enhanced proliferation of hepatic cells, whereas HBV-KMT2B fusion transcripts did not enhance proliferation. HBV-KMT2B-integrated HPCs exhibited replication stress and DNA damage, indicating that our model initiated the process of hepatocarcinogenesis due to abnormally promoted KMT2B function. CONCLUSIONS: Our disease model using genetically engineered iPSCs provides the first insight into both the KMT2B function in HCC development and the oncogenic processes by HBV-KMT2B integration. We clarified the novel oncogenic mechanism in HBV-related HCC due to aberrant KMT2B function.

Humans

Conserved host-exclusive oligonucleotide motifs enriched in pathogenic genes of human oncogenic viruses.

Comparative viral genomics can reveal sequence-level constraints influencing virus-host interactions. Relative minimal absent words (rMAWs) are short oligonucleotide motifs present in viral genomes but completely absent from the host, potentially reflecting selective pressures related to host adaptation and immune evasion. Using the EAGLE algorithm and the GRCh38 human reference genome, we systematically screened for prevalent rMAWs (prMAWs) across six major human oncogenic viruses: Epstein-Barr virus (EBV), hepatitis B virus (HBV), hepatitis C virus (HCV), human papillomavirus (HPV), human T-cell leukemia virus type 1 (HTLV-1), and human herpesvirus 8/Kaposi's sarcoma-associated herpesvirus (HHV-8/KSHV). highly conserved 11- and 12-bp prMAWs were identified in EBV, HBV, HTLV-1, and HHV-8/KSHV, with sequence prevalences ranging from 91.5% to 97.9%. Conversely, no short prMAWs were detected in HCV or HPV, likely reflecting differences in genome architecture, mutation rates, and long-term host adaptation to the human host. Importantly, the identified host-exclusive motifs exhibited non-random genomic distribution and were preferentially embedded within viral genes central to replication, persistence, immune modulation, and oncogenesis, including EBNA-1 (EBV), HBx (HBV), Tax-associated regions (HTLV-1), and lytic replication genes of HHV-8/KSHV. Notably, all detected prMAWs were enriched in GC nucleotides and exhibited marked CpG over-representation, suggesting sequence constraints associated with epigenetic regulation and viral persistence. Collectively, these highly conserved, host-exclusive signatures offer promising, candidates for sequence-directed approaches in the diagnosis, monitoring, and investigation of virus-associated cancers.

Humans

Hepatitis B virus genome mutations in precore and basal core promoter regions among HBeAg-negative chronic hepatitis B patients with high viral load in Indonesia.

Hepatitis B e antigen (HBeAg) is widely used as a marker for active HBV replication and serves as a surrogate for HBV DNA&#x2009;>&#x2009;200,000 IU/mL to determine eligibility for tenofovir disoproxil fumarate (TDF) prophylaxis to prevent vertical transmission, according to WHO guidelines. However, some HBeAg-negative patients still harbor high viral loads. Mutations in the precore (PC) and basal core promoter (BCP) regions may reduce or abolish HBeAg expression without necessarily suppressing viral replication. Next-generation sequencing (NGS)-based characterization of these mutations remains limited in Indonesia. This study aimed to analyze the mutation prevalence in the BCP and PC regions associated with HBeAg negativity in Indonesian patients. We conducted a cross-sectional study of 32 chronic HBV treatment-na&#xef;ve, unvaccinated patients with HBV DNA&#x2009;>&#x2009;200,000 IU/mL (16 HBeAg-negative, 16 HBeAg-positive) at Cipto Mangunkusumo General Hospital. BCP and PC mutations were analyzed using NGS, classifying mutations as major (mutation frequency index [MFI] &#x2265;20%) or minor (MFI 1-&#x2009;<&#x2009;20%). Associations were analyzed using the Chi-square or Fisher's exact test and p-values were adjusted using the Benjamini-Hochberg procedure. Among 29 major mutation sites, PC mutations A1846T/C and G1896A were more frequent in HBeAg-negative than HBeAg-positive patients (81.3% vs 6.3% and 75.0% vs 12.5%, respectively; all adjusted p&#x2009;=&#x2009;0.019). Combined analysis showed higher mutation frequencies in HBeAg-negative patients (93.8%, 81.3%, and 62.5% for A1846T/C, G1896A, and G1899A, respectively; all adjusted p&#x2009;=&#x2009;0.015). In conclusion, HBeAg-negative patients with high viral loads are strongly associated with PC mutations, particularly G1896A, A1846T/C, and G1899A. These exploratory findings provide regional NGS-based molecular evidence that established PC mutations may contribute to the coexistence of HBeAg negativity and continued high-level HBV replication in Indonesian patients. Larger studies incorporating broader virological and clinical comparison groups are required to determine the clinical significance of these findings.

Humans

Hepatitis B virus DNA in primary hepatocellular carcinoma tissue.

Tumour, cirrhotic, and metastatic tissues from four patients with primary hepatocellular carcinoma have been investigated for the presence of hepatitis B viral DNA by nucleic acid hybridization. Tumours from two of three patients with a current HBV infection contained 1--2 genomes per cell of unintegrated viral DNA, while tumours from the third HBs antigen-positive patient contained less than one genome equivalent per ten cells. A tumour from one patient with anti-HBs contained no detectable HBV DNA. A variety of models involving HBV as an etiologic agent may be advanced to explain the statistical correlation of HBV infection with primary hepatocellular carcinoma (PHC). The data presented here argue against the model that HBV DNA integrated into every cell is required to maintain the oncogenic transformation of hepatocytes, but they do not rule out other models.

Adult