Universal Primers for Detection and Sequencing of Hepatitis B Virus Genomes across Genotypes A to G

Towards elimination of chronic viral hepatitis in French Polynesia: results from a national population-based survey

Background

In French Polynesia, hepatitis B virus (HBV) infection appears as a major risk factor for hepatocellular carcinoma (HCC), which detection rate in the Austral archipelago is among the highest in the world. Through a nationally representative cross-sectional survey of the adult population, this study aimed at assessing the prevalence of HBV, but also hepatitis C virus (HCV), and hepatitis delta virus (HDV).

Methods

A total of 1942 blood samples from participants aged 18-69 years were tested for anti-HBc, anti-HBs, HBsAg, anti-HCV IgG, and HDV RNA. Complete genome sequencing of detected HBV strains was performed.

Findings

Among participants, 315/1834, 582/1834, 33/1834, 0/1857, and 0/33 tested positive for anti-HBc, anti-HBs, HBsAg, anti-HCV IgG, and HDV RNA, respectively. The population prevalence of HBsAg was estimated at 1.0% (95% CI: 0.6-1.7). All HBsAg carriers were born in French Polynesia before vaccination at birth became mandatory. In multivariate analyses, identified factors associated with HBsAg carriage included: the archipelago of residence (p < 0.0001), age (p < 0.0001), and education level (p = 0.0077). HBV genotypes B, C, and F were detected.

Interpretation

French Polynesia has a low endemicity level of HBV and its population may be considered at low risk for HCV and HDV infection. However, prevalence of HBsAg was found concerning in Austral (3.8%; 95% CI: 1.9-7.5) and Marquesas (6.5%; 95% CI: 3.8-11) archipelagoes. In the Austral archipelago, the presence of genotype C may account for the elevated rate of HCC. Our findings warrant more efforts to improve access to detection, prevention and care to people born before the systematic vaccination policy application, and residing in higher-risk areas, to achieve HBV elimination in French Polynesia.

Funding

Research Delegation of French Polynesia.

Possible Association between Genetic Diversity of Hepatitis B Virus and Its Effect on the Detection Rate of Hepatitis B Virus DNA in the Placenta and Fetus

Background: The prevalence of HBV infection and HBV genotypes varies from country to country, and the role of HBV genotypes in the presence of HBV in the placenta and fetus has never been explored. This study was conducted to (1) identify HBV genotypes, and their frequencies, that infected Northern Thai pregnant women; (2) evaluate the association between HBV genotypes and the detection rate of HBV DNA in the placenta and fetus; (3) evaluate the association between specific mutations of the HBV genome and HBV DNA detection in placental tissue; and (4) identify the mutation of the HBV genome that might occur between maternal blood, placenta, and cord blood. Methods: Stored samples of the maternal blood, placental tissue, and cord blood that were collected from 145 HBsAg-positive pregnant Thai women were analyzed to identify HBV DNA. Results: Approximately 25% of infected mothers had fetal HBV DNA detection, including cases with concomitant HBV DNA detection in the placenta (77.3%). A total of 11.7% of cases with placental detection had no HBV DNA detection in the maternal blood, indicating that the placenta could be a site of HBV accumulation. Of the 31 HBV-positive blood samples detected by nested PCR, the detected strains were subgenotype C1 (77.4%), subgenotype B9 (9.7%), and subgenotype C2, B2, B4, and recombinant B4/C2 (3.2% for each). Genotype B had a trend in increased risk of placental HBV DNA detection compared to genotype C, with a relative risk of 1.40 (95% CI: 1.07-1.84). No specific point mutation had a significant effect on HBV DNA detection in placental tissue. Mutation of C454T tended to enhance HBV DNA detection in placental tissue, whereas T400A tended to have a lower detection rate. No mutation was detected in different sample types collected from the same cases. Conclusions: HBV DNA detection in the fetus was identified in approximately 25% of HBV-positive mothers, associated with the presence of HBV in the placenta in most cases. The placenta could possibly be a site of HBV accumulation. Subgenotype C1 was the most common subgenotype, followed by subgenotype B9. HBV genotype B possibly had a higher trend in intrauterine detection than HBV genotype C. Mutation is unlikely to occur during intrauterine exposure.

Performance evaluation of in vitro diagnostic kits for hepatitis B virus infection using the regional reference panel of Japan

BACKGROUND

Hepatitis B virus (HBV) infection is a global public health concern. Precise and sensitive detection of viral markers, including HBV DNA and HBs antigen (Ag), is essential to determine HBV infection.

METHODS

The sensitivities and specificities of 5 HBV DNA and 14 HBsAg kits were evaluated using World Health Organization International Standards (WHO IS) and the Regional Reference Panel (RRP) consisting of 64 HBsAg-negative and 80 HBsAg-positive specimens.

RESULTS

All 5 HBV DNA kits detected HBV DNA in the WHO IS at a concentration of 10 IU/mL. The sensitivity and specificity to the RRP were 98.8-100% and 96.9-100%, respectively. HBV DNA titers were well correlated among the 5 kits regardless of HBV genotype. However, discordance of the HBV DNA titer was found in 5 specimens measured by CAP/CTM HBV v2.0. Among 12 automated HBsAg kits, the minimum detectable concentrations in the WHO IS varied from 0.01 to 0.1 IU/mL. Two lateral flow assays were positive for WHO IS concentrations greater than or equal to 1.0 and 0.1 IU/mL, respectively. When analyzed by the RRP, 12 automated kits exhibited a sensitivity of 98.8-100%, and 2 lateral flow assays showed sensitivities of 93.8% and 100%. The specificities of HBsAg kits were 100%. In the quantification of HBsAg, some kits showed a poor correlation of measurements with each other and showed up to a 1.7-fold difference in the regression coefficient of HBsAg titers. There were variations in the correlations of measurements among HBsAg kits when analyzed by genotype.

CONCLUSIONS

Five HBV DNA kits showed sufficient sensitivity and specificity to determine HBV infection. HBV DNA titers were compatible with each other irrespective of HBV genotypes. HBsAg kits had enough sensitivity and specificity to screen for HBV infection. One of the lateral flow assays had a nearly equivalent sensitivity to that of the automated HBsAg kit. HBsAg titers quantified by the evaluated kits were not compatible across the kits. Genotype-dependent amino acid variations might affect the quantification of HBsAg titers.

Molecular detection of hepatitis B virus genotype E with immune escape mutations in chronic hepatitis B patients on long-term antiviral therapy in Jos, Nigeria

Background

Previous studies in Nigeria have reported the presence of hepatitis B virus (HBV) genotype E and the availability of immune escape mutants. There is a paucity of data on chronic patients on long-term antiviral therapy for HBV infection.

Objective

This study assessed HBV genotypes and drug resistance variants among patients with chronic HBV infection receiving tenofovir in Jos, Nigeria.

Methods

This cross-sectional study consecutively enrolled 101 patients (51 with HIV/HBV co-infection and 50 with HBV infection only) on antiviral therapy from February 2018 to May 2019 at four hospitals in Jos, Nigeria. DNA quantification of HBV was performed on all samples; 30 samples with detectable viral load were selected for genotyping using Sanger sequencing by targeting the full-length sequences of reverse transcriptase gene of the HBV genome. Phylogenetic analysis was performed with reference sequences from GenBank. Escape mutant and drug resistance analysis were performed using HBV drug resistance interpretation and Geno2pheno.

Results

Only 30 (29.7%) of the 101 study participants had detectable HBV DNA. Of these, six (20.0%) isolates were successfully amplified and sequenced. The identified genotype was E, including escape mutations L127R (16.7%) and G145A (16.7%).

Conclusion

This study revealed exclusive dominance of genotype E in Nigeria. The S gene mutations G145A and L271R are known to be associated with modified antigenicity and impaired serologic assays, which may cause false negatives in the detection of anti-HBV surface antigen. The presence of mutants that are associated with vaccine immune escape may also have diagnostic and vaccine immune response implications.

Analysis of S gene characteristic sequences and changes in properties of protein expression in HBV ASCs with low-level HBsAg

Objective

We detected the serum HBsAg immune complex (HBsAg-CIC) and sequenced the HBV S gene in these patients to reveal the association between sustained low-level expression of HBsAg and mutated S gene sequence characteristics, protein function changes, and HBsAg immune complex formation.

Methods

A total of 204 samples were collected and divided into high-level (n = 60, HBsAg level >10 IU/ml) and low-level (n = 144, HBsAg level ≤ 10 IU/ml) HBsAg groups. The clinical and epidemiological data of the two groups were statistically compared. According to different serological patterns and genotypes, the HBsAg-CIC results of the high-level and low-level HBsAg groups were divided into different subgroups, and then the HBsAg-CIC positive rates among different subgroups were compared. We sequenced the S gene of HBV from the two groups and identified the relevant mutations in the MHR of the S gene. In addition, we compared the changes in HBsAg protein properties and functions after hot spot mutation in the MHR of the S gene.

Results

Comparing the positive rates of HBsAg-CIC under different serological patterns and genotypes in the two groups, the HBsAg-CIC positive rate was higher in the low-level HBsAg group. Moreover, there was weak correlation between HBsAg-CIC and HBsAg or HBV DNA in both groups (r = 0.32, 0.27, 0.41, 0.48; P < 0.05). Sequencing of S gene in the two groups, showed that the hot-spot mutations were T126A, M133L/T/S, and F134L/T/I in MHR of S gene of genotype B, and hot-spot mutations were Q101R and I126S/T in MHR of S gene of genotype C. Additionally, the positive rate of MHR mutation in the S gene from HBsAg-CIC positive patients was higher in the low-level HBsAg group.

Conclusion

The host immune process of clearing HBV seems to have multiple site mutations in MHR, which changes the physicochemical properties and functions of HBsAg and intensifies the formation of HBsAg-CIC, thus avoiding the effective recognition of HBsAg by the host and resulting in immune tolerance between the host and HBV, which may be one of the formation mechanisms of sustained low-level expression of HBsAg in the serum of HBV-infected persons.

Hepatitis B Virus and Cytomegalovirus Infections Disrupt Sperm Parameters in Males through Decreasing Mitochondrial Membrane Potential: A Case-control Study

Background: Infertility is a global problem that affects more than 15% of couples. The occurrence of this problem is about 50% in males. Viral infections cause infertility in men by different mechanisms. Objectives: This study is designed to evaluate the effects of hepatitis B virus (HBV) and cytomegalovirus (CMV) infection on male fertility and determine the mechanisms involved. Methods: A total of 73 males were included in the present study. They were assigned to the groups healthy fertile (n = 22 volunteers) as the healthy controls, non-infected infertile (n = 27), HBV-infected infertile (n = 14), and CMV-infected infertile (n = 10). The sperm parameters, including count, morphology, progressive motility (PR), and progressive + non-progressive motility (PR + NP), were analyzed in their semen. The semen samples of all studied participants were subjected to polymerase chain reaction to determine the presence of HBV or CMV infection. Mitochondrial membrane potential (MMP) and tumor necrosis factor-alpha (TNF-α) were also assessed. Results: Our findings showed that all sperm parameters, including count, morphology, PR, and PR + NP, decreased in males with HBV and CMV infections compared to the healthy control group (P < 0.01 in all cases). MMP declined in HBV- and CMV-infected males compared to the healthy control group (P < 0.001). Conversely, the TNF-α level of semen in HBV- and CMV-infected men was significantly higher than in the healthy control group (P < 0.001). Conclusions: The results of the present study demonstrated that HBV and CMV infections lead to male infertility through increasing TNF-α and decreasing sperm MMP.

Low Genetic Diversity of Hepatitis B Virus Surface Gene amongst Australian Blood Donors

Variants in the small surface gene of hepatitis B virus (HBV), which codes for viral surface antigen (HBsAg), can affect the efficacy of HBsAg screening assays and can be associated with occult HBV infection (OBI). This study aimed to characterise the molecular diversity of the HBV small surface gene from HBV-reactive Australian blood donors. HBV isolates from 16 HBsAg-positive Australian blood donors' plasma were sequenced and genotyped by phylogenies of viral coding genes and/or whole genomes. An analysis of the genetic diversity of eight HBV small surface genes from our 16 samples was conducted and compared with HBV sequences from NCBI of 164 international (non-Australian) blood donors. Genotypes A-D were identified in our samples. The region of HBV small surface gene that contained the sequence encoding the 'a' determinant had a greater genetic diversity than the remaining part of the gene. No escape mutants or OBI-related variants were observed in our samples. Variant call analysis revealed two samples with a nucleotide deletion leading to truncation of polymerase and/or large/middle surface amino acid sequences. Overall, we found that HBV small surface gene sequences from Australian donors demonstrated a lower level of genetic diversity than those from non-Australian donor population included in the study.

Not uncommon: HBV genotype G co-infections among healthy European HBV carriers with genotype A and E infection

BACKGROUND & AIMS

HBV genotype G (HBV/G) is mainly found in co-infections with other HBV genotypes and was identified as an independent risk factor for liver fibrosis. This study aimed to analyse the prevalence of HBV/G co-infections in healthy European HBV carriers and to characterize the crosstalk of HBV/G with other genotypes.

METHODS

A total of 560 European HBV carriers were tested via HBV/G-specific PCR for HBV/G co-infections. Quasispecies distribution was analysed via deep sequencing, and the clinical phenotype was characterized regarding qHBsAg-/HBV-DNA levels and frequent mutations. Replicative capacity and expression of HBsAg/core was studied in hepatoma cells co-expressing HBV/G with either HBV/A, HBV/D or HBV/E using bicistronic vectors.

RESULTS

Although no HBV/G co-infection was found by routine genotyping PCR, HBV/G was detected by specific PCR in 4%-8% of patients infected with either HBV/A or HBV/E but only infrequently in other genotypes. In contrast to HBV/E, HBV/G was found as the quasispecies major variant in co-infections with HBV/A. No differences in the clinical phenotype were observed for HBV/G co-infections. In vitro RNA and DNA levels were comparable among all genotypes, but expression and release of HBsAg was reduced in co-expression of HBV/G with HBV/E. In co-expression with HBV/A and HBV/E expression of HBV/G-specific core was enhanced while core expression from the corresponding genotype was markedly diminished.

CONCLUSIONS

HBV/G co-infections are common in European inactive carriers with HBV/A and HBV/E infection, but sufficient detection depends strongly on the assay. HBV/G regulated core expression might play a critical role for survival of HBV/G in co-infections.

Clinical characteristics and association analysis of persistent low-level HBsAg expression in a physical examination population with HBV infection

Certain patients with hepatitis B virus (HBV) infection present with persistently low levels of serum hepatitis B surface antigen (HBsAg) and have been indicated to have low rates of HBV nucleic acid replication. To explore the serological and molecular epidemiological characteristics of HBV population with low-level HBsAg in the present study, associated serum markers and virologic genotype detection were performed accordingly. Determination of HBV markers was performed using a chemiluminescence immunoassay from which 2,544 out of 45,256 adults who underwent routine health examination were tested positive for HBsAg. HBV DNA was detected by real-time fluorescent quantitative PCR. The patients were divided into low-level and high-level groups, according to their HBsAg levels (cut-off value, 10 IU/ml). The prevalence and levels of HBsAg positivity and HBV DNA in patients with HBV infection were analyzed by age, sex, serological pattern and clinical type. The fibrosis status of patients with low-level HBsAg was assessed by determining the aspartate aminotransferase-to-platelet ratio (APRI), and sequencing was employed to determine serotypes and genotypes. HBV-infected patients with low-level HBsAg (<10 IU/ml) accounted for 15.41% of the 2,544 HBsAg-positive patients, and the prevalence of HBsAg positivity exhibited a tendency to increase with age. The male-to-female ratio was ~1.9:1, and the average age was 54.98±16.28 years among HBV-infected patients with low-level HBsAg. The major serological pattern and clinical types were HBsAg/antibody against hepatitis Be antigen (anti-HBe)/antibody against hepatitis B core antigen (anti-HBc)-positive (94.90%) and chronic asymptomatic (ASC) (97.95%), respectively. HBV DNA exhibited a low-level of replication and the prevalence of HBV DNA positivity assessed by the routine method and by the enrichment method was 27.74% (97/392) and 45.92% (180/392), respectively. No significant differences among the age groups were identified in the different HBsAg level groups (P>0.05). The prevalence of HBV DNA positivity was associated with HBsAg only in patients with serological pattern HBV-M2 (HBsAg/anti-HBe/anti-HBc-positive) in the low-level HBsAg group (odds ratio: 1.30; 95% CI: 1.15–1.47; P<0.05). The APRI had no association with age, HBsAg, HBV DNA level or liver function index in ASC patients in the low-level HBsAg group (P>0.05). The prevalence of the serotype adw and genotype B was 85.53 and 89.47%, respectively. Further improvement in the systematic study of populations with low-level HBsAg has important clinical and epidemiological significance for improving the detection of HBV serological markers, elucidating the mechanisms leading to low-level HBsAg, overcoming immune tolerance to eliminate HBV infection and preventing HBV transmission.

Pro-oncogenic, intra host viral quasispecies in Diffuse large B cell lymphoma patients with occult Hepatitis B Virus infection

Non Hodgkin lymphoma, predominantly Diffuse Large B-cell Lymphoma (DLBCL) has been reported to have a significant association with Hepatitis B virus (HBV). We investigated the presence of different gene segments of HBV in plasma, B-cells and tumor tissues from DLBCL patients and explored the genetic variability of HBV within and across different compartments in a host using Next Generation Sequencing. Despite all 40 patients being HBV seronegative, 68% showed evidence of occult HBV. Sequencing of these gene segments revealed inter-compartment viral variants in 26% of them, each with at least one non-synonymous mutation. Between compartments, core gene variants revealed Arg94Leu, Glu86Arg and Ser41Thr while X gene variants revealed Phe73Val, Ala44Val, Ser146Ala and Ser147Pro. In tumor compartments per se, several mis-sense mutations were detected, notably the classic T1762A/A1764G mutation in the basal core promoter. In addition, a virus surface antigen mis-sense mutation resulting in M125T was detected in all the samples and could account for surface antigen negativity and occult HBV status. It would be interesting to further explore if a temporal accumulation of viral variants within a favored niche, like patients’ lymphocytes, could bestow survival advantage to the virus, and if certain pro-oncogenic HBV variants could drive lymphomagenesis in DLBCL.

Development of a point-of-care test to detect hepatitis B virus DNA threshold relevant for treatment indication

Background

Hepatitis B virus (HBV) has been the most prevalent blood-borne pathogen wherein utero transmission has still not been properly managed. Recent practice guidelines suggested that an antiviral drug should be administered to third-trimester pregnancies with significant viremia (>2 × 105 IU/mL).

Objectives

To develop a novel turbidity-based loop-mediated isothermal amplification (LAMP) coupled with heat treatment DNA extraction method that is a rapid, cost-effective, and feasible viral load assessment and could be applied to antenatal screening.

Methods

Primers and reagents were designed, turbidity-based platform and heat treatment method were added, and evaluated for optimal efficiency. Assay sensitivity was tested from serially diluted standard HBV DNA. Assay specificity was tested with six standard viral DNAs. Clinical samples were analyzed and the results were compared with those of quantitative polymerase chain reaction (qPCR) diagnostic records.

Results

The optimized condition was 60°C with no betaine, 1.4 mM deoxyribonucleotide triphosphates (dNTPs) and 6 mM of MgSO4 for 60 min. The assay accurately detected samples with standard HBV DNA at >2 × 105 IU/mL in both distilled water and spiked serum. Results can be interpreted within 31.48 ± 1.41 min in real-time turbidimeter. The amplification is exclusively specific to HBV, but not with the other six human-specific viruses. Moreover, the assay showed comparable performance within 95% confidence interval to the previously developed HBV LAMP toward clinical specimens.

Conclusions

This newly developed method was accurate, affordable, and flexible to further implementation to large-scale third-trimester pregnancy screening.

Analysis of clinical characteristics and S gene sequences in chronic asymptomatic HBV carriers with low-level HBsAg

BACKGROUND

During the natural hepatitis B virus (HBV) infection process, some infected subjects are characterized by a sustained low serum HBV surface antigen (HBsAg) expression level. Most members in this population are chronic asymptomatic HBV carriers (ASCs). To elucidate the mechanism underlying low-level HBsAg expression in ASCs, we sequenced the HBV S gene in these patients to reveal specific sequence characteristics.

METHODS

Overall, 1308 cases of chronic ASCs were grouped according to their HBsAg serum expression levels (10 IU/mL). The clinical characteristics of the population were analysed in detail. The HBV S gene was sequenced from 276 ASC cases with low-level HBsAg expression. Additionally, 100 of 1032 ASC cases with high-level HBsAg expression were randomly selected for HBV S gene sequencing based on age matching according to the low-level HBsAg group. A comparative analysis was conducted with the HBV S gene sequences from ASCs with low HBsAg expression and the HBV reference S gene sequences from ASCs with high HBsAg expression.

RESULTS

The population with low-level HBsAg expression displayed the following primary clinical characteristics: mostly chronic asymptomatic HBV carriers, older age (mean age 55.09 years), HBsAg/anti-HBe/anti-HBc (core) positivity as the main serological pattern (97.1%), low HBV DNA replication (1.32 ± 1.60 log₁₀ IU/mL), a low HBV-DNA positive rate (45.65%) and primarily genotype B (82.54%) and serotype adw (84.13%). The comparative analysis of the HBV S gene sequences from ASCs with low-level HBsAg showed significant mutations (including co-mutations) on both sides of the main hydrophilic region (MHR).

CONCLUSION

Significant mutations in multiple regions and at multiple sites (including co-mutations) on both sides of the MHR may be one cause of the low HBsAg expression level in this population.

Fully automated sequence alignment methods are comparable to, and much faster than, traditional methods in large data sets: an example with hepatitis B virus

Aligning sequences for phylogenetic analysis (multiple sequence alignment; MSA) is an important, but increasingly computationally expensive step with the recent surge in DNA sequence data. Much of this sequence data is publicly available, but can be extremely fragmentary (i.e., a combination of full genomes and genomic fragments), which can compound the computational issues related to MSA. Traditionally, alignments are produced with automated algorithms and then checked and/or corrected "by eye" prior to phylogenetic inference. However, this manual curation is inefficient at the data scales required of modern phylogenetics and results in alignments that are not reproducible. Recently, methods have been developed for fully automating alignments of large data sets, but it is unclear if these methods produce alignments that result in compatible phylogenies when compared to more traditional alignment approaches that combined automated and manual methods. Here we use approximately 33,000 publicly available sequences from the hepatitis B virus (HBV), a globally distributed and rapidly evolving virus, to compare different alignment approaches. Using one data set comprised exclusively of whole genomes and a second that also included sequence fragments, we compared three MSA methods: (1) a purely automated approach using traditional software, (2) an automated approach including by eye manual editing, and (3) more recent fully automated approaches. To understand how these methods affect phylogenetic results, we compared resulting tree topologies based on these different alignment methods using multiple metrics. We further determined if the monophyly of existing HBV genotypes was supported in phylogenies estimated from each alignment type and under different statistical support thresholds. Traditional and fully automated alignments produced similar HBV phylogenies. Although there was variability between branch support thresholds, allowing lower support thresholds tended to result in more differences among trees. Therefore, differences between the trees could be best explained by phylogenetic uncertainty unrelated to the MSA method used. Nevertheless, automated alignment approaches did not require human intervention and were therefore considerably less time-intensive than traditional approaches. Because of this, we conclude that fully automated algorithms for MSA are fully compatible with older methods even in extremely difficult to align data sets. Additionally, we found that most HBV diagnostic genotypes did not correspond to evolutionarily-sound groups, regardless of alignment type and support threshold. This suggests there may be errors in genotype classification in the database or that HBV genotypes may need a revision.

An epidemiological survey of HBV infection and low-level HBsAg in military camps in eastern China

This study aimed to investigate hepatitis B virus (HBV) infection in military personnel in eastern China, which will provide a basis for the prevention of HBV infection.A total of 15,508 soldiers and 2386 officers were recruited from military camps in eastern China. The markers, deoxyribonucleic acid, serotypes, and genotypes of HBV in serum were detected and analyzed.Hepatitis B surface antigen (HBsAg) positive rate was 0.44% in soldiers, in whom the low-level HBsAg accounted for 88.24%. The HBsAg positive rate was 1.72% in officers in whom the low-level HBsAg accounted for 12.20%. There were significant differences in the prevalence of high-level and low-level HBsAg, HBV serotypes, HBV DNA positive rate, and mean log HBV DNA between officers and soldiers (P < .05). Compared with the conventional method for HBV DNA extraction, the enrichment method for HBV DNA extraction could significantly improve the positive rate and quantification of HBV DNA by real-time fluorescence quantitative polymerase chain reaction (P < .05). Sequencing of S gene in HBV was used for the determination of serotype and genotype of HBV. The sequencing success rate was significantly different between soldiers and officers (P < .05) as well as between high-level HBsAg group and low-level HBsAg group (P < .05). Significant difference was also observed in the genotype distribution between soldiers and officers (P < .05).HBV infection displays a low prevalence and a low epidemic state, and the prevalence of low-level HBsAg is higher in soldiers. We should pay attention to improve the quality of conscription examination as well as emphasize the surveillance, prevention, and protection of HBV infection in military officers.

Sequence analysis of the Pre-S gene in chronic asymptomatic HBV carriers with low-level HBsAg

In a hepatitis B virus (HBV)-infected population, persistently low expression levels of serum HBV serum antigen (HBsAg) are present, particularly in chronic asymptomatic HBV carriers (ASCs). The present study sequenced the HBV Pre-S gene, and aimed to elucidate its features in ASCs with low HBsAg expression compared with in the established HBV Pre-S reference gene sequences from ASCs with high HBsAg expression. A total of 1,308 ASCs were grouped according to HBsAg serum levels (cut-off value, 10 IU/ml), and clinical characteristics were analyzed in detail. The HBV Pre-S gene was sequenced in 276 ASCs with low-level HBsAg; in addition, 100 of the remaining 1,032 ASCs with high-level HBsAg were randomly selected for HBV Pre-S gene sequencing on the basis of age matching with the low-level HBsAg group. Comparative analysis of the gene sequences from these groups was subsequently conducted. The major clinical features of the population with low-level HBsAg were as follows: Most were ASCs with chronic HBV infection; 97.1% were HBsAg/anti-HBe/anti-HBc-positive; 82.54% carried the B genotype; and 84.13% displayed the adw serotype. The results indicated that there were novel and meaningful mutations, including co-mutations, at numerous loci and sites in the Pre-S gene, as well as deletion mutations in the Pre-S2 gene. These mutations in the Pre-S1 and Pre-S2 gene frag ments accounted for 65.38% (68/104) of the 104 B genotype cases in the low-level HBsAg group and 90.91% (20/22) of the 22 C genotype cases in the low-level HBsAg group, respectively. In conclusion, Pre-S gene mutations may be associated with HBV replication defects, which may be the cause of the observed low expression levels of HBsAg.

Integrating nested PCR with high-throughput sequencing to characterize mutations of HBV genome in low viral load samples

Due to the low viral load of hepatitis B virus (HBV) in plasma samples, conventional techniques have limitations to the detection of antiviral resistance mutations. To solve the problem, we developed a fast, highly sensitive, and accurate method to sequence the HBV whole-genome sequencing in plasma samples which had various viral loads from very low to high.Twenty-one plasma samples were collected from patients who were carriers of HBV from the Hangzhou First People's Hospital. Two pairs of conserved, overlapping, nested primers were used to amplify and sequence the whole HBV genome in 8 plasma samples with different viral loads. High-throughput sequencing was performed on Illumina MiSeq platform. Concomitantly, 3 samples were directly sequenced without PCR amplification. We compared amplicon-sequencing with direct sequencing to develop a method for amplifying and characterizing the whole genome of HBV.HBV genome was amplified from all samples and verified by Sanger sequencing, regardless of the viral loads. Sequencing results revealed that only a few reads were mapped to the HBV genome following direct sequencing, while the amplicon-sequencing reads had a good coverage and depth. We identified 50 intrahost single nucleotide variations (iSNVs), 14 of which were low frequency mutations. Interestingly, iSNVs were more common in low viral load samples than in high viral load samples, and mutations in the reverse transcriptase (RT) region were most prevalent.We conclude that amplicon-sequencing is not only a practical method to detect HBV infection with a high sensitivity and accuracy but also enables to detect mutations in the HBV genome in low viral load samples from HBV-infected patients. Thus, our findings provide a new diagnosis method of HBV infection, which is capable of detection of low frequent mutations in low viral load samples.

Complete Genome Sequence of the WHO International Standard for Hepatitis B Virus DNA

The World Health Organization (WHO) international standard (IS) for hepatitis B virus (HBV) DNA for use in nucleic acid amplification assays was characterized by determining the complete genome sequence, which was assigned genotype A. This information will aid the design, development, and evaluation of HBV DNA amplification assays.