[Relationship between the immunohistopathological changes of hepatitis B virus carrier mothers' placentas and fetal hepatitis B virus infection].

OBJECTIVE

To investigate the role of placenta in intrauterine transmission of hepatitis B virus (HBV), and the relationship between the fetal HBV infection and the placental infection.

METHODS

Cord blood or peripheral blood was obtained from 61 newborn infants of HBsAg positive mothers. Neonates (28 of 61) infected by HBV were assigned to fetal infected group, and 33 infants without infection were assigned to control group. Histopathological changes of placentas from 61 HBsAg positive mothers were observed by pathological examination and classification.

RESULTS

(1) The positive rate of HBsAg/HBcAg detected in the placentas of fetal infected group was 82% (23/28), which was significant higher than that of control group (55%), P < 0.05. (2) Among various types of cells in placental tissue, the amnionic cell showed higher HBsAg/HBcAg positive rate in fetal infection group, which was 36% (10/28), than that of control group (6%) (P < 0.01). (3) The syncitial cell was the cell with the higher detecting HBsAg/HBcAg positive rate (49%) comparing with other types of cells in placental barrier (P < 0.05). (4) The incidence of fibrinoid necrosis and chorionic hyperemia in fetal infection group were 29% and 50%, respectively, which were higher than those in control group (9%, 15%). The detecting rate of Hofbauer cell in fetal infection group was 46%, significantly lower than that in control group (79%) (P < 0.05).

CONCLUSIONS

HBV infection of fetus is associated with placental infection. HBV infection of amnionic cell is an important factor of intrauterine infection. Placental barrier can protect the fetuses from infection to some extent. Some histopathological changes of placental tissue, for example fibrinoid necrosis, chorionic hyperemia and decreasing number of Hofbauer cells, may play a role in fetal HBV infection.