[Relationship between HBeAg from HBsAg positive mothers and regulatory T cells in neonates and its influence on HBV intrauterine transmission]

Objective: To explore the relationship between HBeAg in HBsAg positive mothers and CD(4)(+)CD(25)(+)Foxp3(+)regulatory T cells (Treg) in newborns, as well as how they would influence the increasing risk on HBV intrauterine transmission. Methods: We collected information on general demographic characteristics and delivery on 270 HBsAg positive mothers and their newborns from the Third People's Hospital of Taiyuan. Fluorescence quantitative polymerase chain reaction (FQ-PCR) and chemiluminescence immunoassay (CLIA) were used to detect HBV DNA and HBV serological markers in peripheral blood from both mothers and neonates. The expression of Treg and other immune cells in peripheral blood of neonates were detected with flow cytometry (FCM). Results: Maternal HBeAg positive rates were associated with an increased risk of intrauterine transmission (OR=4.08, 95%CI: 1.89-8.82). Rates of Treg in newborns born to HBsAg-positive mothers were higher than that of the negative group (Z=2.29, P=0.022). Each pair of the subjects was assigned to five different groups according to the HBeAg titers of mothers. Frequencies of both Treg and HBeAg in newborns and HBV DNA in mothers between the above said 5 groups showed similar trends of changing patterns and the differences between groups were statistically significant(χ(2)=18.73, P<0.001; χ(2)=181.60, P<0.001; χ(2)=183.09, P<0.001). Results from partial correlation analysis showed that after adjusting for neonatal HBeAg and maternal HBV DNA, mother's HBeAg titers were positively related to the percentage of Treg in their newborns (r(s)=0.19, P=0.039). In addition, the frequencies of Treg were negatively correlated with pDC and CD(4)(+) T cell in their newborns (r(s)=-0.21, P=0.017; r(s)=-0.23, P=0.009). Conclusion: HBeAg from HBsAg positive mothers might have inhibited the function of neonatal DC cells and T cells to reduce the immune response to HBV by up-regulating the proportion of Treg and finally increased the risk of HBV intrauterine transmission.