Quasispecies characters of hepatitis B virus in immunoprophylaxis failure infants

The relationship of maternal hepatitis B e antigen and response to vaccination of infants born to women with chronic infection

BACKGROUND

The relationship of maternal HBeAg and infants' response to hepatitis B vaccine remains controversial. This study aims to observe the dynamic changes in infant birth HBV markers and study the time-varying effects of maternal HBeAg on vaccination response of infants born to women with chronic HBV infection.

METHODS

3163 infants born to HBsAg positive mothers including 1737 with maternal HBeAg positive in group A and 1426 negative in group B were enrolled eventually. Demographic information and laboratory tests were collected at birth, 7-12th and 24th month. The dynamic changes of infant HBV markers and HBsAb titers at different time points were compared between the two groups.

RESULTS

The infant HBV markers at birth displayed different modes. During the follow-up, we observed a significant downward trend in the positive rates of HBsAg, HBeAg, HBeAb and HBcAb. The HBsAg of two groups switched to negative at 7-12 months and HBeAg in Group A became negative at 24 months. The HBsAb titers of the infants in the two groups were 576.91(192.8-1000.0) vs 719.67(208.1-1000.0) at 7-12 months (Z = -3.049, P = 0.002) and 783.5(227.8-1000.0) vs 891.4(234.0-1000.0) at 24 months (Z = -0.853, P = 0.394). High HBV DNA viral load (OR 1.260, 95% CI 1.139-1.395, P < 0.001) and maternal HBeAg level (OR 1.003, 95% CI 1.002-1.003, P < 0.001) were associated with the higher HBeAg positive rate of infants.

CONCLUSIONS

Maternal HBeAg did affect the infants' immune response to vaccination and reduce the anti-response at 7-12th month temporarily, but these influences were negligible by 24th months after birth, which proved that the maternal HBeAg would not induce immune tolerance of infants from a long-term perspective.

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.

Diagnosis experiences from 50 hepatitis B patients in Chongqing, China: a qualitative study

Background

The aim of this study was to provide recommendations for reducing the impact of hepatitis B infection on patients with chronic hepatitis B by describing their experiences during the diagnosis process.

Methods

We conducted face-to-face interviews with 50 hepatitis B patients recruited by convenient sampling from an infectious diseases department of a teaching hospital in Chongqing, China from July to August 2019. Thematic analysis framework included interviewees’ social demographic characteristics, diagnosis approach, signs and symptoms before diagnosis, feelings after diagnosis, and doctor’s instructions.

Results

Most patients first detected hepatitis B through various types of physical examinations when the patients were asymptomatic or had only mild symptoms. Most patients were shocked, scared, or overwhelmed when they were diagnosed with hepatitis B. They were able to remember the doctor’s instructions about maintaining a healthy lifestyle, but not impressed by the doctor’s advice about regular follow-up liver function tests. The lack of regular follow-up has caused irreversible damage to some patients.

Conclusions

Most patients are passively diagnosed with hepatitis B due to their lack of awareness on active hepatitis B prevention. Patients need professional mental health care to overcome the negative emotions that following the diagnosis. Physicians’ instruction should emphasize the importance of regular follow-up liver function tests in addition to a healthy lifestyle.

Approach to women who become pregnant while on tenofovir disoproxil fumarate for chronic B hepatitis: A report of two cases

Mother-to-child transmission of hepatitis B virus can occur during the intrauterine, antenatal and postnatal periods, with an increased risk of perinatal transmission. Appropriate management of patients who are hepatitis B surface antigen positive during pregnancy can substantially reduce the rates of perinatal transmission. Herein, two pregnant women with chronic hepatitis B are presented; one became pregnant while receiving tenofovir disoproxil fumarate and continued the treatment during pregnancy, the other discontinued tenofovir disoproxil fumarate treatment on her own due to conception, but restarted at 26 weeks of pregnancy. At birth the newborns of both women were vaccinated and immunoglobulin was given, with no perinatal transmission. Whether pregnant women should receive antiviral therapy or immunoprophylaxis still remains controversial. In order to keep the mother's liver stable and to prevent perinatal transmission, it is of paramount importance to manage pregnant women in line with the current information and guidelines.

Quasispecies characteristic in "a" determinant region is a potential predictor for the risk of immunoprophylaxis failure of mother-to-child-transmission of sub-genotype C2 hepatitis B virus: a prospective nested case-control study

OBJECTIVE

This study was performed to explore the correlation between the characteristics of hepatitis B virus (HBV) quasispecies in HBV-infected pregnant women and the risk of immunoprophylaxis failure for their infants.

DESIGN

In this prospective nested case-control study, the characteristics of HBV quasispecies in mothers whose infants were immunoprophylaxis success (control group) and those whose infants were immunoprophylaxis failure (case group) were analysed by the clone-based sequencing of full-length HBV genome and next-generation sequencing (NGS) of "a" determinant region, and were compared between the two groups.

RESULTS

The quasispecies characteristics including mutant frequency, Shannon entropy and mean genetic distance at amino acid level of "a" determinant region were significantly lower in case group than that in control group, using the full-length HBV genome clone-based sequencing assay. These results were confirmed by NGS assay. Notably, we discovered that the differences were also significant at nucleotide level by NGS assay. Furthermore, the risk of immunoprophylaxis failure could be predicted by analysing the three HBV quasispecies characteristics either at nucleotide level or at amino acid level of "a" determinant region, and the corresponding predictive values were tentatively set up.

CONCLUSIONS

HBV quasispecies with a more complex mutant spectrum in "a" determinant region might be more vulnerable to extinct through mother-to-child-transmission (MTCT). More importantly, analysing HBV quasispecies characteristics in pregnant women with high HBV DNA load might be helpful to predict the high-risk population of immunoprophylaxis failure, and consequently provide accurate intervention against MTCT 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.

Clinical efficacy and safety in telbivudine- or tenofovir-treated hepatitis B e antigen-positive pregnant women

BACKGROUND

Telbivudine (LdT) and tenofovir (TDF) are widely used in pregnant women to prevent vertical transmission; however, limited data are available on the differences in clinical efficacy and safety between the two drugs.

METHODS

A total of 307 hepatitis B e antigen (HBeAg)-positive pregnant women with complete follow-up data were enrolled, the patients with alanine aminotransferase (ALT) levels <1×ULN at baseline were enrolled to cohort 1 for treatment from 28 ±4 weeks gestation to delivery, while ALT levels >1×ULN at baseline were enrolled to cohort 2 for treatment from 28 ±4 weeks gestation and continued after delivery. The clinical efficacy and safety was compared in LdT- and TDF-treated patients. In addition, 32 patients in cohort 1 were analysed for nucleoside analogue (NA)-related resistance mutations at baseline and after delivery.

RESULTS

The results showed that HBV DNA levels were significantly lower at delivery than at baseline (P<0.001), but the decreases in HBV DNA, ALT, total bilirubin and total bile acid levels did not differ between the LdT- and TDF-treated patients at different time points (P>0.05) in the two cohorts. However, gastrointestinal adverse effects (vomiting) occurred more frequently in TDF-treated than LdT-treated patients (6.6% versus 0.0%; P=0.001). The results of NA-related resistance mutations analysis in cohort 1 revealed that short-term LdT or TDF treatment did not significantly change the NA-related resistance mutations (P>0.05).

CONCLUSIONS

This study revealed that the clinical efficacy in LdT- or TDF-treated HBeAg-positive Chinese pregnant women is similar, and gastrointestinal adverse effects occurred more frequently in TDF-treated patients.

Deep sequencing of hepatitis B surface antigen gene in the preserved umbilical cords in immunoprophylaxis failure against mother-to-child HBV transmission

BACKGROUND

Vaccine escape mutants (VEMs) are one of the causes of breakthrough infections in the mother-to-child transmission of hepatitis B virus (HBV). We hypothesized that VEMs existing as minor populations in the maternal blood are associated with breakthrough infections in children. We sought to determine whether VEMs exist as minor populations in the preserved umbilical cords of children with breakthrough infections.

CASE PRESENTATION

Two families (Family 1: three children, Family 2: two children) were enrolled. Despite immunoprophylaxis, a breakthrough infection occurred in two Family 1 children and two Family 2 children. Preserved umbilical cords, serum, and nails were used for the HBV DNA analysis. To detect VEMs, we performed direct and deep sequencing of hepatitis B surface antigen gene. The direct sequencing showed that there were no VEMs in the serum of the children or mother of Family 1 and family 2, but it identified a G145A mutant in the nails of the mother of Family 2. In Family 1, deep sequencing detected a T143S mutant as a minor population (1.7-2.0%) in the umbilical cords and serum of all three children and in the serum of the mother. A T126A mutant was also detected in the umbilical cord (9.2%) and serum (7.0%) of the first-born child of Family 1. In Family 2, the deep sequencing showed no VEMs in the umbilical cords, but it detected D144A (2.5%) and G145A (11.2%) mutants in the serum of the 2nd-born child.

CONCLUSIONS

VEMs were present as minor populations in the preserved umbilical cords of children with breakthrough infections. The VEMs did not become major populations after the breakthrough infections. The evolution of VEMs from a minor form to a major form might not be a prerequisite for breakthrough infections in mother-to-child transmission.

Hepatitis B virus surface gene mutants in immunoprophylaxis-failed infants from Southern China

Hepatitis B virus (HBV) vaccination was considered the most powerful tool for prevention of HBV transmission from mother to infant. In 1992, a universal HBV vaccination program for infants was launched in China. The aim of this study was to investigate the HBV surface antigen (HBsAg) variations in immunoprophylaxis-failed infants, vaccine free infant patients and adult chronic hepatitis B (CHB) patients (without nucleoside analog treatment). Immunoprophylaxis-failed infants were recruited from two centers (Guangdong and Chongqing, representing Southern China). HBV serum markers, including HBsAg, hepatitis e antigen (HBeAg), and core antigen, were detected by the enzyme-linked immunosorbent assay. HBV DNA load was detected by quantitative polymerase chain reaction. Nucleotide sequences encoding HBsAg were amplified and analyzed. Frequencies of amino acid substitutions within the second loop of "a" determinant (region with greater local hydrophilicity) in immunoprophylaxis-failed infants were clearly higher than the unvaccinated infant patients and adult CHB patients (9.6% vs 0% vs 3.8%; χ ²  = 7.454; P = 0.024). More than 50% (52.8%) aa substitutions in immunoprophylaxis-failed infants were located in B cell epitopes, while 64.6% aa substitutions in adult CHB patients were located in CTL cell epitopes. HBeAg negative patients had higher substitution frequency in CTL and Th cell epitopes, and in immunoprophylaxis-failed infant patients with substitution in major hydrophilic region region had a higher alanine aminotransferase level (68.6 ± 111.5 vs 62.1 ± 132.2; P = 0.026), and lower DNA load (7.03 ± 1.72 vs 7.82 ± 1.73; P < 0.001). In conclusion, our results observed vaccine-induced immune selection pressure in vaccine failed infants, substitutions in "a" determinant, especially the G145 substitution was still the most stable and remarkable site of vaccine escape.

Amino acid substitutions Q129N and T131N/M133T in hepatitis B surface antigen (HBsAg) interfere with the immunogenicity of the corresponding HBsAg or viral replication ability

Variants of hepatitis B surface antigen (HBsAg) influenced its antigenicity and immunogenicity. In our study, we aim to investigate biological significance of amino acid (aa) substitutions in HBsAg, Q129 N and T131 N/M133 T, for glycosylation, antigenicity and immunogenicity of variant HBsAg (vtHBsAg) and viral replication. Expression plasmids of vtHBsAg with aa substitutions Q129 L, T123 N, Q129 N and T131 N/M133 T were constructed. Immunofluorescence (IF) staining and Western blot were simultaneously utilized to examine expression of vtHBsAg proteins in Huh7 cells transfected with vtHBsAg constructs. vtHBsAg of Q129 N and T131 N/M133 T created new N-glycosylation and displayed perinuclear distribution by IF staining with the anti-HA. Antigenicity of vtHBsAg of Q129 N and T131 N/M133 T was reduced compared with wild type (wt) HBsAg. In addition, we discovered impaired ability to induce anti-HBs responses against wtHBsAg in mice immunized with plasmids pHBsAg- Q129 N and T131 N/M133 T. Even so, efficient protective response toward wild type HBV can be primed by the two vtHBsAgs in mice. Further, we discovered that vtHBsAg with Q129 N distinctly impaired HBV replication capacity, but vtHBsAg with T131 N/M133 T had no impact on viral replication. Thus, we conclude that vtHBsAg with Q129 N or T131 N/M133 T creates new N-glycosylation and interferes with both the antigenicity and immunogenicity of vtHBsAg. And vtHBsAg with Q129 N impaired HBV replication ability.