Effects of intrauterine exposure to maternal-derived HBeAg on T cell immunity in cord blood

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.

Characterization of T cell immunity in chronic hepatitis B virus-infected mothers with postpartum alanine transaminase flare

BACKGROUND

Postpartum alanine transaminase (ALT) flares occur frequently in chronic hepatitis B virus (HBV)-infected mothers with antepartum antiviral therapy (AVT). We aimed to characterize the T cell immunity in HBV-infected mothers experiencing postpartum ALT flares.

METHODS

Twenty HBV-infected pregnant women who received AVT at 26-28 weeks of gestation were enrolled and followed up until 15-18 weeks postpartum. Among the 20 HBV-infected pregnant women, 6 experienced postpartum ALT flare (AF mothers), while 14 did not (NAF mothers). T lymphocyte phenotypes and functions were analyzed using flow cytometry.

RESULTS

Compared to NAF mothers, the quantitative HBsAg levels in AF mothers decreased significantly at 6-8 or 15-18 weeks postpartum. Significant differences in HBeAg levels between these groups were only found at delivery. Regulatory T cell (Treg) numbers in AF mothers were lower than those of NAF mothers before AVT; however, there were no significant differences in Treg numbers at other follow-up points. Expression of other T cell phenotypes were similar between the two groups. T cells in AF mothers produced more pro-inflammatory cytokines (IFN-γ, IL-21, TNF-α, IL-2) or less anti-inflammatory cytokine (IL-10) than those in NAF mothers before, during, or after antiviral treatment. The ratio of IFN-γ to IL-10 producing by CD4⁺ T cells or CD8⁺ T cells was higher in AF mothers than that in NAF mothers during pregnancy or after delivery.

CONCLUSIONS

The characteristics of T cell immunity was distinct between mothers with postpartum ALT flare and those without ALT flare from pregnancy to postpartum, which indicated that T cell immunity might get involved in postpartum ALT flare.