Quantitative Hepatitis B Surface Antigen Predicts Hepatitis B Transmission in Infants Born to e Antigen-positive Mothers

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.

Predicting hepatitis B e Antigen seroconversion after pregnancy-The SydPregScore

BACKGROUND AND AIMS

Achieving Hepatitis B e antigen seroconversion (HBeAg SC) at an earlier age confers a better prognosis. We examined baseline and post-partum factors associated with HBeAg SC after pregnancy. We developed a tool, the SydPregScore, to estimate the likelihood of HBeAg SC in the years after pregnancy.

METHODS

A retrospective analysis of an HBeAg-positive pregnant cohort was conducted. Variables including baseline age, parity, alanine aminotransferase level, HBV viral load, quantitative HBsAg, use of antiviral therapy and post-partum flare were collected. Univariate and multivariate Cox regression analyses to determine predictors of HBeAg SC and develop a predictor score were performed.

RESULTS

We analysed HBeAg SC rates in 220 pregnancies to 149 HBeAg-positive women from 2006 to 2019. At baseline, their median age was 33 (IQR 29-37), ALT 23 U/L (IQR 17-33) and viral load 8 log₁₀ IU/mL (IQR 6.3-8.2 log₁₀ IU/mL). The majority (133/198, 67.2%) received short-course antiviral therapy to prevent mother-to-child transmission, and 109/192 (56.8%) had a post-partum flare. HBeAg SC occurred in 74/220 (33.6%) after pregnancy (median follow-up 814 days, IQR 405-1531). Multivariate analysis identified baseline viral load <8 log₁₀ IU/mL (HR 2.426 [1.224-4.809], p = .011), baseline ALT ≥2 ULN (HR 2.726 [1.299-5.721], p = .008) and age <35 (HR 2.859 [1.255-6.513], p = .012) to be positive predictors of HBeAg SC. The 'SydPreg Score' estimated the probability of HBeAg SC at 2000 days as 10%, 30%, 70% and 80% for 0, 1, 2, and 3 predictors respectively.

CONCLUSION

The SydPreg Score allows the prediction of HBeAg SC in the years after pregnancy. Even in those without elevated ALT, age <35 and viral load <8 log₁₀ IU/mL can identify women with a good chance of subsequent HBeAg SC. Those without a chance may benefit from viral suppression.

Tenofovir disoproxil fumarate therapy to prevent hepatitis B virus vertical transmission-A review of maternal and infant outcomes

Hepatitis B virus (HBV) is a global health problem. Vertical transmission of HBV from HBV surface antigen (HBsAg)-positive mothers to their infants is the most common cause of HBV infection worldwide. The use of passive-active immunoprophylaxis is >90% effective in reducing the risk of vertical transmission, but immunoprophylaxis failure can occur in infants born to mothers with high viraemia. Thus, it is recommended that pregnant women with HBV-DNA level >200 000 IU/ml receive nucleos(t)ide analogue (NA) treatment [i.e. tenofovir disoproxil fumarate (TDF), lamivudine or telbivudine] during third trimester to prevent infant immunoprophylaxis failure. TDF is recommended as the first-line therapy based on available data on efficacy, safety and resistance profile. However, maternal immunological reconstitution following parturition can increase immune-mediated flares to viral antigens that is potentially exacerbated following TDF withdrawal. In this article, we review available data on the efficacy and safety of TDF administration to prevent HBV mother-to-child transmission. We also discuss changes in maternal viral markers [i.e. HBV-DNA, HBV e antigen and HBsAg] and alanine aminotransferase during follow-up post-partum in mothers received NA to prevent HBV vertical transmission.

Kinetics of hepatitis B surface antigen in pregnant women with and without tenofovir disoproxil fumarate

Tenofovir disoproxil fumarate (TDF) is the preferred treatment to prevent mother-to-infant transmission in highly viremic HBV-infected women. Data on hepatitis B surface antigen (HBsAg) levels in pregnant women are lacking. We aimed to investigate prepartum and postpartum HBsAg kinetics and its correlation with HBV DNA in pregnant women. HBV-infected mothers with HBV DNA ≥7.5 log₁₀  IU/ml were tested for HBsAg and HBV DNA from baseline to 6 months postpartum. Of the 186 pregnant women with comparable baseline HBsAg and HBV DNA, 101 received TDF from the third trimester until 1 month postpartum. At delivery, TDF group had mildly lower HBsAg (4.32 ± 0.47 vs. 4.54 ± 0.35 log₁₀  IU/ml, p = .0004) and markedly lower HBV DNA (4.26 ± 0.97 vs. 8.11 ± 0.70 log₁₀  IU/ml, p < .0001) than the control group. In the TDF group, mean reduction of HBsAg and HBV DNA from baseline to delivery were 0.22 ± 0.38 and 3.96 ± 0.93 log₁₀  IU/ml. HBsAg reduction had a positive correlation (r = .309; p = .0017) with HBV DNA reduction, and was predictive of HBV DNA reduction ≥3 log₁₀  IU/ml (area under the receiver operating characteristic curve, 0.67; 95% confidence interval, 0.50-0.82). At 6 months postpartum, TDF and control group had comparable HBsAg and HBV DNA. In conclusion, HBsAg decreased slightly at delivery in pregnant women receiving TDF. For monitoring the effect of antiviral therapy during pregnancy, HBV DNA is a better marker than HBsAg. Our data provided valuable information regarding monitoring HBV-infected pregnant women using antiviral therapy.

Maternal hepatitis B e antigen can be an indicator for antiviral prophylaxis of perinatal transmission of hepatitis B virus

As a high-risk factor of perinatal HBV transmission, the potential role of maternal hepatitis B e antigen (HBeAg) to guide antiviral prophylaxis has not yet been fully reported. This large prospective cohort study enrolled 1177 hepatitis B surface antigen (HBsAg)-positive pregnant women without antiviral treatment and their newborns. HBeAg, HBsAg, and viral load in maternal serum collected before delivery were measured. All the newborns were given standard passive-active immunoprophylaxis within 12 h after birth, and post-vaccination serologic testing was performed at 7 (±7d) months of age. The results revealed that 20 of the 1177 infants (1.70%) were immunoprophylaxis failure, and all their mothers were HBeAg positive. Maternal quantitative HBeAg was positively correlated with viral load (r = 0.83; P < .0001) and quantitative HBsAg (r = 0.68; P < .0001). The area under the receiver operating characteristic curve (AUC) for predicting immunoprophylaxis failure by maternal HBeAg was comparable to that by maternal viral load (0.871 vs 0.893; P = .441) and HBsAg (0.871 vs 0.871; P = .965). The optimal cutoff value of maternal quantitative HBeAg to predict perinatal infection was 2.21 log₁₀ PEI U/mL, and the sensitivity and specificity was 100.0% and 74.5%, respectively. According to maternal viral load >2 × 10⁵ IU/mL, the sensitivity and specificity of maternal qualitative HBeAg to identify the risk of HBV MTCT for pregnant women and determine the necessity for antiviral prophylaxis was 95.5% and 92.6%, respectively. This study showed that maternal HBeAg can be a surrogate marker of HBV DNA for monitoring and evaluating whether antiviral prophylaxis is necessary for preventing perinatal HBV transmission.

Quantitative HBsAg and Qualitative HBeAg Predicts Intrauterine Placental Infection and Umbilical Blood Cord in Pregnant Women

Objective: To know the correlation between quantitative Hepatitis B surface Antigen (HbsAg) and maternal Hepatitis B Envelope Antigen (HbeAg) with hepatitis B intrauterine transmission via placental infection. Hepatitis B in pregnancy causes a mother to child transmission (MTCT) via transplacental route started with placental infection. HBV DNA viral load and HBeAg are the independent risk factors for MTCT, but it rarely available in developing country.

Materials and methods: A cross-sectional study in 33 pregnant women with HbsAg positive in 4 referral hospital in East Java, Indonesia. Quantitative HBS Ag and HBeAg) status were determined serologically from a peripheral venous blood sample. Placental Hepatitis B infection was detected by immunohistochemistry of HBsAg from placental tissues. The intrauterine transmission was diagnosed by positive HBsAg in cord blood sampling after deliveries.

Results: Serum quantitative HBsAg level has a good sensitivity and spesificity to predict placental infection (90% and 83%), with a cut off value of 3.14 Log10 IU/mL (AUC 0.87; 95% CI: 0.74-0.99). Quantitative HBsAg level also has a good sensitivity and spesificity to predict HBV transmission in umbilical blood cord (81.8% and 95.5%) with a cut off value of 3.62 log₁₀ IU/ml (AUC: 0.925, 95% CI: 0.813-1; p = 0.000). Placental infection is significantly related with intrauterine transmission with OR 4.6 (95% CI 2.29-9.4; p = 0.002).

Conclusion: The study reveals that maternal serum quantitative HBsAg level can be used as an alternative test to substitute HBeAg or HBV DNA as a marker to predict the placental infection and intrauterine transmission, especially in low-middle income countries.