乙型肝炎病毒宫内感染的机制

目的 探索乙型肝炎病毒（HBV）宫内传播的机制和时间。方法 孕妇和新生儿血清HBsAg和HBVDNA检测采用ELISA和PCR法，引产胎儿肝组织和胎盘的HBsAg，HＢt HBVDNA检测采用ＡＢＣ免疫组化染色和原位杂交。结果 母亲外周血HBV高浓度（≥0.02ug.L^-1)、先光早产和胎盘毛毛细血管内皮细胞HBV感染导致宫内感染发生的危险性比值比（OR）分别为7.06，13.08和16.15，胎盘HBV感染从孕早期、孕中期至足月分娩愈来愈严重且广泛，在足月分娩胎盘中，从母面蜕膜细胞至胎儿面绒毛毛细血管内皮细胞HBV感染率呈逐渐下降趋势，但胎儿宫内感染的OR值却越来越大，1例孕19wk引产胎儿肝组织中检出HBVDNA和抗原。结论 胎儿宫内感染的发生可经2条途径，即血源性和细胞性，宫内感染可发生孕9wk前，但主要时期是在孕晚期。

Mechanism of intrauterine infection of hepatitis B virus

AIM To explore the mechanism and timing of hepatitis B virus(HBV) intrauterine infection. METHODS Serologic HBV infection markers of pregnant women and newborns were detected by ELISA and PCR. HBsAg, HBxAg, HBcAg and HBV DNA in placentas and fetal abortion liver tissue were determined by ABC immunohistochemical staining and in situ hybridization. RESULTS Intrauterine infection ORs of high concentration (≥0.02 μg.L-1) of HBV in maternal peripheral blood, threaten premature labour and placental villous capillary endothelial cell (VCEC) infection were 7.06, 13.08 and 16.15, respectively. The infection extent in placenta became gradually serious with the continuing of pregnant period. With placental infection gradually near to fetal side from maternal side, the OR of intrauterine infection had an increasing trend. One induced aborted fetal liver tissue (19 wk of pregnancy) was detected having the proteins and DNA of HBV. CONCLUSION There may be two intrauterine transmission routes-hematogenous and cellular transfer routes. The intrauterine infection can occur before the 19th week of pregnancy, but the main timing is possibly in the third-trimester pregnancy.