乙型肝炎病毒宫内传播因素和机制的分子流行病学研究

目的应用分子流行病学方法研究乙型肝炎病毒（ＨＢＶ）经胎盘引起宫内感染的危险因素与机制,方法 收集连续性入院的４０２例乙型肝炎表面抗原阳性孕妇及其新生儿作为研究对象,其中,发生宫内感染的１５例作为病例组,余为对照组,进行病例对照研究,同时分别检测１８２份与１８５份母血的ＨＢｓＡｇ滴度和ＨＢＶＤＮＡ浓度,筛选危险因素;另外收集胎盘标本进行免疫组化染色与原位杂交,确定ＨＢＶ感染状状;最后进行综合分析。结

A molecular epidemiology study on risk factors and mechanism of HBV intrauterine transmission

OBJECTIVE: To clarify the risk factors and mechanism of HBV intrauterine infection by molecular epidemiology method. METHODS: We performed a case-control study. 402 HBsAg-positive pregnant women and their infants were collected as subjects. 15 infants infected by HBV intrauterine transmission were selected as case group and others as controls. Besides, HBsAg titer in 182 maternal sera and HBV DNA concentration in 185 maternal sera were determined. To identify the HBV infection in the placentas, immunohistochemistry stain and HBV DNA hybridization in situ were conducted. The data from both laboratory and epidemiological fields were analysed. RESULTS: The findings indicated that the positiveness of HBeAg in mother's sera (OR = 17.07) and the history of threatened premature labour (OR = 5.44) were the main risk factors. Intrauterine transmission was significantly related to HBsAg titers and HBV DNA concentration in mother's sera (P = 0.01). The results of immunochemistry stain and HBV DNA situ in hybridization in the placentas from 101 full-term pregnancy women showed that HBV infection rates had a decreasing trend (P = 0.0009) from mother's side to fetus's in placenta and there was a significant association between HBV intrauterine transmission and HBV infection in villous capillary endothelial cells in placenta (OR = 18.46, P = 0.0002). CONCLUSION: There might be a "cellular transfer" of HBV infection in the placenta. With regard to the mechanism of HBV intrauterine transmission; there are two transmission routes, namely, hemagenous route and cellular route.