Influence of HBV gene heterogeneity on the failure of immunization with HBV vaccines in eastern China

C2729T mutation associated with HBV mother-to-child transmission reduces HBV production via suppressing LHBs expression

Mother-to-child transmission (MTCT) is still the main route of hepatitis B virus (HBV) infection. However, the virological factors affecting HBV MTCT have not been fully elucidated. In this study, based on a prospective cohort of mother-infant pairs with positive maternal hepatitis B surface antigen (HBsAg), we found that the average nucleotide mutation rate of HBV preS1 promoter (SPI) region in the immunoprophylaxis success group was significantly higher than that in the immunoprophylaxis failure group. Among the nucleotide mutations of the HBV SPI region, the C2729T mutation had the highest frequency. Next, we found that the C2729T mutation promoted HBsAg release but reduced HBV production by suppressing the expression of large hepatitis B surface antigen (LHBs), and overexpressing LHBs could rescue this phenomenon. Based on the fact that the C2729T mutation could alter the binding site of hepatocyte nuclear factor 1 (HNF1) in the HBV SPI region, we uncovered that such an alteration could downregulate the transcriptional activity of SPI by attenuating the binding ability of HNF1 and HBV SPI region. This study suggests that HBV C2729T mutation may contribute to the immunoprophylaxis success of HBV MTCT by reducing HBV production, which supplements the virological factors affecting HBV MTCT.

Vertical Transmission of Hepatitis B Virus-An Update

Hepatitis B virus (HBV) infection is a major public health problem in the world. Approximately 296 million people are chronically infected. In endemic areas, vertical transmission is a common route of transmission. There are several strategies for the prevention of HBV vertical transmission, such as antiviral treatment during the third trimester of pregnancy and immunoprophylaxis to newborns that includes the administration of hepatitis B immune globulin (HBIG) and an HBV vaccine. Despite this, immunoprophylaxis failure can occur in up to 30% of infants born to HBeAg-positive mothers and/or with high viral load. Therefore, management and prevention of HBV vertical transmission is of paramount significance. In this article, we provided a review of the epidemiology, mechanisms of pathogenesis and risk factors of vertical transmission, as well as the strategies implemented to prevent the infection.

HBx 128–133 Deletion Affecting HBV Mother-to-Child Transmission Weakens HBV Replication via Reducing HBx Level and CP/ENII Transcriptional Activity

Some infants born to hepatitis B surface antigen (HBsAg)-positive mothers, especially born to hepatitis B e antigen (HBeAg)-positive mothers, can still be infected with hepatitis B virus (HBV) through mother-to-child transmission (MTCT) of HBV and develop chronic HBV infection. At present, the virological factors affecting HBV MTCT are still unclear. In this study, we found that the mutation rates of amino acids in the HBV X region were high, and there were obvious differences between the immunoprophylaxis success group and the immunoprophylaxis failure group of HBeAg-positive mothers. Specifically, the mutation rate of HBx 128–133 deletion (x128–133del) or corresponding nucleotide 1755–1772 deletion (nt1755–1772del) in the immunoprophylaxis success group was significantly higher than that in the immunoprophylaxis failure group. Furthermore, we found that x128–133del could weaken HBV replication by reducing the level of the HBx protein due to the increased proteasome-dependent degradation of HBx protein, and the transcriptional activity of HBV core promoter (CP)/enhancer II (ENII) due to the attenuated binding capacity of hepatocyte nuclear factor 4α (HNF4α) to HBV CP/ENII. This study suggests that x128–133del may contribute to immunoprophylaxis success, which may be helpful in clarifying the virological mechanism affecting HBV MTCT and formulating an optimal immunization strategy for children born to HBeAg-positive mothers.

Asian Pacific association for the study of liver (APASL) guidelines: hepatitis B virus in pregnancy

Hepatitis B virus (HBV) infection still remains a major public health issue in the Asia-Pacific region. Most of the burden of HBV-related disease results from infections acquired in infancy through perinatal or early childhood exposure to HBV in Asia-Pacific. Hepatitis B during pregnancy presents unique management issues for both the mother and fetus. These APASL guidelines provide a comprehensive review and recommendations based on available evidence in the literature, for the management of females with HBV infection through every stage of pregnancy and postpartum. These also address the concerns, management challenges, and required follow-up of children born to hepatitis B-positive mothers.

Expression of S100 proteins is associated with HBV intrauterine transmission

PURPOSE

The mechanisms underlying HBV intrauterine transmission remain unknown. In this study, we explored the mechanism of HBV intrauterine transmission by iTRAQ proteomics analysis.

METHODS

iTRAQ technology was applied to perform comparative proteomics studies on six HBV^+/+ neonates and six HBV^+/- neonates whose mothers and fathers were HBsAg positive and paternal HBsAg negative, respectively. The data obtained from the mass spectrometer were analyzed using MASCOT ( https://matrixscience.com ) to qualitatively and quantitatively compare the differentially expressed proteins in the two groups. Gene Ontology and KEGG pathway analyses were performed to analyze the differentially expressed proteins. The expressions of HBV intrauterine transmission-related proteins in serum samples and corresponding placental tissues were further verified by immunohistochemistry and Western Blot. Then, the human trophoblast cell line (Swan71) infected with HBV was used to analyze the potential mechanisms of HBV intrauterine transmission under the mediation of differential proteins.

RESULTS

A total of 35 differentially expressed proteins, including 17 up-regulated proteins and 18 down-regulated proteins, were identified by comparing serum protein expression levels in HBV^+/+ and HBV^+/- neonates. The differentially expressed proteins were mainly related to RAGE receptor binding, NF-kappa B transcription factor activity, innate immune response, defense response to bacterium, and the signaling pathway in pathogenic microorganism infection. The expressions of S100A8/9/12 in HBV^+/+ maternal placenta tissue were significantly increased. The expressions of S100A8/9/12 proteins in Swan71 cells were significantly increased after HBV infection.

CONCLUSION

High expression of S100 proteins may be associated with the intrauterine-transplacental transmission of HBV.

Hepatitis B and Pregnancy: Virologic and Immunologic Characteristics

The hepatitis B virus (HBV) is an important human pathogen. Unvaccinated infants infected through mother-to-child transmission (MTCT) are at >95% risk of developing serum hepatitis B surface antigen-positive chronic hepatitis B (CHB). Despite complete passive-active HBV immunoprophylaxis, approximately 10% of infants born to mothers who are highly viremic develop CHB, and thus maternal treatment with nucleos(t)ide analogs (tenofovir disoproxil fumarate, lamivudine, or telbivudine) is recommended in the third trimester of pregnancy to reduce MTCT risk. Viral rebound usually occurs after stopping treatment and, in the context of maternal immunologic reconstitution postpartum, can also precipitate host immune-mediated hepatic (biochemical) flares. In this article, we review the epidemiology of HBV MTCT, discuss management and potential mechanisms of HBV vertical transmission, and highlight recent studies on virologic and immunologic aspects of hepatitis B in pregnancy and postpartum.

Hepatitis B Virus Immunization and Neonatal Acquisition of Persistent Infection in England and Wales

Background

It is believed that between 2% and 5% of infants born to hepatitis B virus (HBV)-infected mothers at a high risk of perinatal transmission will become persistently infected despite immunization starting at birth. We investigated factors associated with breakthrough infections.

Methods

Sixty-nine samples from HBV-infected infants born between 2003 and 2015 were tested for HBV serological and molecular markers. Sequencing and epitope phenotyping were used to investigate alterations in hepatitis B surface antigen (HBsAg) sequence and antigenicity in infants and in mothers known to have transmitted and not to have transmitted virus to their infants.

Results

Vaccine/hepatitis B immune globulin uptake was complete in the majority of HBV-infected infants. A minority (8 [12%]) had detectable plasma antibody to HBsAg at 12 months. Twenty-five of 68 (37%) infants harbored a virus with amino acid changes in the HBsAg "a" determinant, of which 13 displayed altered HBsAg antigenicity. Viral load was 30-fold higher in maternal samples from those who transmitted.

Conclusions

Our data provide evidence to suggest that immune selection drives change at mother-infant transmission, resulting in the alteration of HBsAg antigenicity. These changes may play a role in immunization failure, but other factors including viral load may be more important. Continued monitoring of vaccine efficacy is essential.

Host Genetic Variants in HLA Loci Influence Risk for Hepatitis B Virus Infection in Children

BACKGROUND

Hepatitis B virus (HBV) infection is a serious public health problem in China and worldwide. Mother-to-child transmission is one of HBV's main transmission routes in highly endemic regions. Genome-wide association studies (GWAS) identify single nucleotide polymorphisms (SNPs) at HLA loci as associated with HBV infection. However, the mechanisms of HBV perinatal transmission and breakthrough in children have not yet been clearly defined.

OBJECTIVES

We aimed to explore the association between SNPs at HLA loci and HBV infection and breakthrough in children.

METHODS

A total of 274 HBV-infected children and 353 controls were selected among children aged between 6 months and 12 years in China. Seven SNPs at HLA-DP and HLA-DQ loci were genotyped to analyze their association with HBV infection in children.

RESULTS

Alleles G in both HLA-DPA1 rs3077 and HLA-DPB1 rs9277535 were found to be significantly associated with HBV infection in children with odds ratios (OR) of 1.309 (95% CI 1.046 to 1.639) and 1.411 (95% CI 1.125 to 1.771), respectively. In addition, overdominant analysis found that the rs2281388 (HLA-DPB1) GA genotype and the rs9366816 (HLA-DPB2) TC genotype were related to HBV infection (rs2281388, OR = 1.422, 95% CI: 1.032-1.961; rs9366816, OR = 1.444, 95% CI: 1.045-1.994). Furthermore, this study highlighted that rs9277535 was also significantly associated with HBV breakthrough infection in children whose mothers were positive for hepatitis B surface antigen (HBsAg).

CONCLUSIONS

Our study confirmed that genetic variants in HLA-DPA1 and HLA-DPB1 loci have significant associations with HBV infection, especially with HBV breakthrough in children. This study provides insight into HBV infection in children and is valuable for the targeted management of, and control strategies for, this disease.

[Hepatitis B and pregnancy. Part 2. Nine practical issues about delivery and neonatal care]

In France, the hepatitis B maternal-fetal transmission prevention strategy is based on serovaccination at birth. Serum therapy is to inject 30IU/kg of anti-HBs specific immunoglobulins of human origin in the first hours of life, which in practice corresponds to 1ml or 100IU. Vaccination should also be performed during the first hours of life, and a new injection should be performed at 1month and 6months. In infants less than 32weeks and/or less than 2kg, lower vaccine response leads to prescribe an additional injection at 2months. This serovaccination reduces the risk of mother to child transmission from 57 to 4 %. The failure risk factors of serovaccination are high maternal viral load (greater than or equal to 7 log) and/or the presence of HBeAg. The delivery route does not change the risk of maternal-fetal transmission of hepatitis B when serovaccination at birth was well conducted. Likewise, breastfeeding does not change the risk of maternal-fetal transmission of hepatitis B after serovaccination. It is recommended by WHO. During labor, the pH in utero should be done only when strictly necessary, the published data do not allow to conclude on the risk of transmission.

[Hepatitis B and pregnancy. Part 1. Thirteen practical issues in antenatal period]

In France, the prevalence of chronic hepatitis B is about 1% in pregnant women (usually asymptomatic carriers of HBsAg). The risk of maternal-fetal transmission of hepatitis B is particularly high when viral load measured by PCR is higher in mothers (above 7 log) or HBeAg is present. In case of maternal-fetal transmission of hepatitis B, the risk to the newborn of developing subsequent chronic hepatitis B is very high (90%), with long-term complications such as cirrhosis and hepatocellular carcinoma. The prevention of maternal-fetal transmission is based on systematic testing for hepatitis B during pregnancy, followed by serovaccination of the newborn at birth. If necessary, amniocentesis can be realised but will avoid the realization of a transplacental gesture. In case of high viral load, the establishment of a maternal antiviral treatment with lamivudine or tenofovir from 28SA can further reduce the risk of transmission. Given the low resistance it induces, tenofovir should be used preferentially.

Hepatitis B e antigen status and hepatitis B DNA levels in women of childbearing age with chronic hepatitis B infection screening for clinical trials

BACKGROUND

Perinatal or mother-to-child transmission of hepatitis B virus (HBV) results in a high frequency of chronic infection. Risk of mother-to-child transmission is associated with maternal viral factors including hepatitis B e antigen (HBeAg) positivity and viral load.

AIM

To investigate associations between age, HBeAg status, HBV DNA levels and genotype in female patients screened for inclusion into two contemporary, randomized HBV trials.

METHODS

Retrospective analyses focused on differences between women of childbearing age (≤44 years) and older women. Female patients (N = 355; 18-69 years) were included in the analysis: 41.7% of patients were Asian. In total, 44.4% were HBeAg-positive.

RESULTS

Significantly more women aged ≤44 years were HBeAg-positive compared to women ≥45 years (57.2% versus 27.5%, respectively, p<0.0001), this proportion declined with increasing age. Younger women were significantly more likely to have high HBV viral load (HBV DNA>108 copies mL: ≤44 years 46.0% vs ≥45 years 25.5%, respectively; p<0.0001), and this declined with increasing age. HBeAg positivity was slightly higher in Asian women, associated with a higher proportion of HBV genotypes B and C in this population. There was no obvious relationship between genotype and viral load.

CONCLUSIONS

Women of childbearing age with CHB are more likely to have high HBV viral load and HBeAg positivity than older women; this likelihood decreases with age. Maternal serological and virological status should therefore be established early in pregnancy, taking into account age and genotype, and a risk-reducing strategy implemented in any patient who is HBeAg positive and has a high viral load.

Prevention of neonatal hepatitis B virus transmission

Hepatitis B virus (HBV) vertical transmission remains a worldwide issue but is fairly uncommon in the western world due to routine screening and vaccination. Universal screening of pregnant women during the second trimester facilitates interruption of mother-to-child transmission (MTCT) by identifying HBV-infected mothers for whom intervention may reduce MTCT risk. HBV DNA level is the single most important predictor of MTCT. Other risk factors include HBeAg, HBe Ab, anti-HB core IgG, and HIV status. Current recommendations for infants born to HBsAg-positive mothers include administration of HBIG within 12 hours of birth and first dose of HBV vaccine within 24 hours of birth. Antiviral therapy is recommended in the third trimester of pregnancy in a subset of patients based on HBeAg and HBV DNA status for prophylaxis of MTCT, although discontinuation of antivirals after delivery is associated with significant increased risk of flares. This article outlines the data for prevention of vertical transmission of HBV.

Immunoprophylaxis failure against vertical transmission of hepatitis B virus in the Chinese population: a hospital-based study and a meta-analysis

BACKGROUND

Despite effective immunoprophylaxis, vertical transmission of hepatitis B virus (HBV) from infected mothers still occurs. This study aimed to provide an estimate of the prevalence of immunoprophylaxis failure and evaluate associated risk factors.

METHODS

A hospital-based prospective study was conducted from June 1, 2008, to June 30, 2012. In this prospective study, 294 HBsAg-positive mothers were followed up from their first prenatal care visits until their infants completed the proposed vaccination schedule. Further, studies providing prevalence rates of immunoprophylaxis failure in the Chinese population were identified from electronic databases and were collected for a meta-analysis.

RESULTS

In the prospective study, 16 (5.44%) infants developed HBV infection despite passive-active immunoprophylaxis. Twelve of these infants were born to HBeAg-positive mothers with cord blood that was positive for HBV DNA. After adjusting for maternal and infant factors, HBV DNA detectable in cord blood (odds ratio: 22.32, 95% confidence interval: 4.00-124.47) was associated with a significantly greater risk of immunoprophylaxis failure. The prospective study and 23 previous studies were included in the meta-analysis, constituting a total of 7561 Chinese participants. The overall estimated rates of immunoprophylaxis failure for infants with HBsAg-positive and HBeAg-positive mothers were 4.87% and 9.66% respectively.

CONCLUSIONS

Immunoprophylaxis failure is an extensive problem, and further studies should design and assess novel strategies for the prevention of immunoprophylaxis failure, especially for cases involving HBeAg-positive mothers and infants with cord blood that is positive for HBV DNA.

Optimal management of HBV infection during pregnancy

Chronic hepatitis B virus (HBV) infection in pregnancy presents a unique and important challenge. Over 50% of chronic HBV carriers in endemic areas acquire infection vertically from their mothers. More importantly, over 90% of perinatally acquired infections progress to chronic HBV infection. Thus, management of chronic HBV during pregnancy and strategies to prevent mother-to-child transmission is an important step in eradicating or reducing the global burden of chronic hepatitis B. In addition, chronic HBV infection in pregnancy presents a unique clinical challenge because of the complex relationship between the physiological changes of pregnancy and the pathophysiological response to HBV. This review will present the current knowledge and a practical approach to management of HBV in pregnancy.

HBV perinatal transmission

Hepatitis B is a serious public health problem all around the world. It is a blood-borne and sexually transmitted DNA virus in adults, but mother to child transmission of hepatitis B virus also occurs in infants born to hepatitis B surface antigen positive mothers.

Chronic hepatitis B virus infection and pregnancy

Planning of pregnancy and management of chronic hepatitis B virus during pregnancy includes recognition of maternal virological status, assessment of liver disease severity and minimization of risk for mother to infant transmission of infection. Decisions regarding the use of antivirals during pregnancy need to be individualized. Monitoring for infection and immunization in newborns is also important. For mothers on antiviral therapy, breastfeeding is not recommended.

Molecular analysis of hepatitis B virus associated with vaccine failure in infants and mothers: a case-control study in Thailand

Perinatal transmission of hepatitis B virus (HBV) has been controlled incompletely despite adequate immunoprophylaxis in infants. The aim of this study was to characterize virological factors of HBV associated with vaccine failure in Thailand. Sera of 14 infected infants (13 HBeAg-positive and one HBeAg-negative) with vaccine failure and their respective mothers (group M1) were tested quantitatively for HBV DNA by real-time PCR, HBV genotypes and mutations were characterized by direct sequencing. Sera collected from 15 HBeAg-positive (group M2) and 15 HBeAg-negative (group M3) mothers whose infants had been vaccinated successfully served as controls. The results showed that group M1 and group M2 mothers had equal titers of HBV DNA but higher titers than group M3. All infected infants and their respective mothers had the same HBeAg status and HBV genotypes. DNA analysis in a pair of HBeAg-negative infant and mother revealed that both were infected with an HBV precore mutant (G1896A). Escape mutants in the "a" determinant region (residues 144 and 145) were detected in two (14%) infected infants. The prevalence of BCP mutations/deletions in groups M2 and M3 was higher significantly than in group M1 (P = 0.022 and P < 0.001, respectively). In conclusion, instead of the HBeAg status, a high titer of HBV DNA in mothers was the major contributor to perinatal transmission of HBV. Escape mutants might be associated with vaccine failure in some infants. BCP mutations/deletions in mothers might contribute to the prevention of mother-to-infant transmission of HBV.

An algorithm for risk assessment and intervention of mother to child transmission of hepatitis B virus

BACKGROUND & AIMS

Despite immunoprophylaxis, mother to child transmission (MTCT) of hepatitis B virus (HBV) still occurs in infants born to hepatitis B surface antigen (HBsAg)-positive mothers. We analyzed methods of risk assessment and interventions for MTCT.

METHODS

We reviewed 63 articles and abstracts published from 1975-2011 that were relevant to MTCT; articles were identified using the PubMed bibliographic database.

RESULTS

Administration of HB immunoglobulin and HB vaccine to infants at birth (within 12 hours), followed by 2 additional doses of vaccines within 6-12 months, prevented approximately 95% of HBV transmission from HBsAg-positive mothers to their infants. However, HBV was still transmitted from 8%-30% of mothers with high levels of viremia. It is important to assess the risk for MTCT and identify mothers who are the best candidates for intervention. The most important risk factor is maternal level of HBV DNA >200,000 IU (10(6) copies)/mL; other factors include a positive test result for the HB e antigen, pregnancy complications such as threatened preterm labor or prolonged labor, and failure of immunoprophylaxis in prior children. Antiviral therapy during late stages of pregnancy is the most effective method to reduce transmission from mothers with high levels of viremia, but elective cesarean section might also be effective. Antepartum administration of HB immunoglobulin, giving infants a double dose of HB vaccine, or avoiding breastfeeding had no impact on MTCT.

CONCLUSIONS

HBsAg-positive mothers should be assessed for risk of MTCT, and infants should receive immunoprophylaxis. Pregnant women with levels of HBV DNA >200,000 IU/mL should be considered for strategies to reduce the risk for MTCT. We propose an algorithm for risk assessment and patient management that is based on a review of the literature and the opinion of a panel of physicians with expertise in preventing MTCT.

Impact of the implementation of a vaccination strategy on hepatitis B virus infections in China over a 20-year period

Hepatitis B virus (HBV) vaccination has been recommended for all neonates in China since 1992. This article reviews the impact of HBV vaccination throughout the past 20 years in China. Before the introduction of the HBV vaccination program, approximately 9.8% of the general Chinese population tested positive for hepatitis B virus surface antigen (HBsAg). Since 1992, vaccination coverage has increased each year. In 1999, a National Expanded Programme on Immunization (EPI) review showed that the immunization coverage with three doses of HBV vaccine was 70.7%, and reached 99.0% in Beijing. The HBsAg carrier rate in the general population decreased to 7.2% in 2006. In particular, the prevalence of HBsAg decreased to 2.3% among children aged 5-14 years and to 1.0% among children younger than 5 years. In addition, the administration of the HBV vaccine may have reduced the risk of hepatocellular carcinoma among adults. Despite the administration of hepatitis B immunoglobulin and the HBV vaccine to children with HBsAg-positive mothers, the failure rate of HBV immunoprophylaxis was 5-10%. In China, vaccine failure was related to HBV S gene mutation and inadequate administration of HBV vaccine. The prevalence of HBV carriers in China was markedly reduced after the introduction of the universal HBV vaccination program. If we immunize all susceptible individuals with the hepatitis B vaccine (especially children), interrupt transmission, and provide antiviral treatment for existing HBV carriers, the number of new cases may be reduced to close to zero in the future and this may eventually result in the eradication of HBV.

Long-term protection against hepatitis B after newborn vaccination: 20-year follow-up

BACKGROUND

Hepatitis B vaccination in children born to hepatitis B surface antigen (HBsAg)-positive mothers considerably decreases the risk of vertical transmission. However, whether this protection against carriage of hepatitis B virus is maintained into early adulthood is as yet unknown.

PATIENTS AND METHODS

A combined passive-active immunization programme for newborns of HBsAg-positive mothers was initiated in the north-eastern part of the Czech Republic in 1988. The number of immunized newborns had reached 665 newborns by the end of 2006. All mothers of immunized infants were HBsAg-positive during pregnancy, and 34 (5%) were also hepatitis B e antigen (HBeAg)-positive. The immunization programme consists of providing newborns with protection at birth with hepatitis B immunoglobulin, followed by three 10-μg doses of plasma-derived or, since 1990, recombinant vaccine administered at 0, 1 and 6 months of life. Only 29 children of HBeAg-positive mothers received vaccine at 0, 1 and 2 months of life. Blood samples were obtained after immunization, at 2 years of age, and biennially thereafter. Samples were tested for HBsAg and hepatitis B surface and core antibodies (anti-HBs, anti-HBc).

RESULTS

The immunization schedules were completed in 640 children. A protective anti-HBs level after immunization was proven in 574 of 620 children (93%). Persistence of protective anti-HBs antibodies was detected in 70, 40 and 25% of children at 5, 10 and 15 years of age. Vertical transmission with chronic HBsAg carrier status was detected in two infants. Anti-HBc seroconversion was proven in ten children from 3 to 15 years of age. Natural boosting with an anti-HBs increase was detected in 38 children (twice in one child).

CONCLUSION

Our results show that combined active-passive immunization of newborns against hepatitis B provides persistent protection up to adolescence despite a frequent waning of anti-HBs antibodies, suggesting there is no need for booster vaccination during adolescence.

Hepatitis B virus genotypes and evolutionary profiles from blood donors from the northwest region of China

Hepatitis B virus (HBV) is prevalent in China and screening of blood donors is mandatory. Up to now, ELISA has been universally used by the China blood bank. However, this strategy has sometimes failed due to the high frequency of nucleoside acid mutations. Understanding HBV evolution and strain diversity could help devise a better screening system for blood donors. However, this kind of information in China, especially in the northwest region, is lacking. In the present study, serological markers and the HBV DNA load of 11 samples from blood donor candidates from northwest China were determined. The HBV strains were most clustered into B and C genotypes and could not be clustered into similar types from reference sequences. Subsequent testing showed liver function impairment and increasing virus load in the positive donors. This HBV evolutionary data for China will allow for better ELISA and NAT screening efficiency in the blood bank of China, especially in the northwest region.