Is hepatitis B antigen in cord blood an immunotolerogen playing a critical role in the pathogenesis of chronic hepatitis B?

Recently, we showed that infants with or without fetal hepatitis B e antigen (HBeAg) exposure had comparable antibody response to hepatitis B vaccination and proposed that fetal HBeAg exposure appears to not induce immunotolerance to HBV. Here, we summarized the different results on the topic of fetal HBeAg exposure in inducing immunotolerance to HBV nucleocapsid protein, and the evidence to back up that the tendency of high infection rate in infants of HBeAg-positive mothers is more likely associated with higher maternal viral loads and is less likely associated with the fetal HBeAg exposure. We consider that whether fetal HBeAg exposure plays an important role in the pathogenesis of chronic HBV infection remains to be an open question.