孕早期母血胎盘滋养层细胞的检测

Detection of trophoblasts from maternal blood

为从孕妇血中检测和分离胎盘滋养层细胞，对５５例孕８～１４周母血中细胞滋养层Ｈ３１５和合体滋养层ＦＴ１－４１．１抗原阳性细胞分别进行了免疫细胞化学检测、流式细胞分析、荧光激活细胞分离（ＦＡＣＳ）及荧光原位杂交分析（ＦＩＳＨ）。结果在２８例和１４例孕妇外周血中分别检出了Ｈ３１５和ＦＴ１－４１．１抗原阳性细胞；而１３名怀男胎孕妇外周血Ｈ３１５阳性细胞经ＦＡＣＳ分选及Ｙ染色体探针的ＦＩＳＨ分析，其中杂交阳性细胞含量平均为１１．４±４．３％。认为：孕８～１４周母血循环中存在细胞滋养层和合体滋养层细胞，有可能利用这些细胞在孕早期对胎儿染色体非整倍性异常进行产前分子细胞遗传学诊断。

Objective: To detect and isolate the trophoblasts from peripheral maternal blood. Design: Experimental cell and molecular biology study. Settings: The Genetic laboratory of National Research Institute for Family Planning. Subjects: 55 Chinese pregnant women at 8th to 14th gestational weeks. Methods: The H315 antigen positive cells in maternal peripheral blood from 28 pregnant women were detected with monoclonal antibodies, McAb H315 against membrane antigen expressed on the placental trophoblasts by APAAP technique. The trophoblastic antigen positive cells from the peripheral blood of another 14 pregnant women were detected by flow cytometry with McAb H315 and monoclonal antibody namely McAb FT1 41.1 against syncytiotrophoblastic membrane antigen. In addition,H315 positive and negative cells were isolated from the peripheral blood of 13 pregnant women bearing male fetus by using fluorescence activated cell sorting (FACS) technique, and were verified by fluorescence in situ hybridization (FISH) with Y chromosome specific DYZ 1 probe. Results: The fetal trophoblast cells were only present in the trophoblastic antigen positive populations, and 11.4± 4.3% of the H315 positive sorted cells showed positive signnal with the Y probe. Conclusions: At least two types of trophoblasts, including cytotrophoblast and syncytiotrophoblast cells were found in the maternal blood in the first trimester. Also, the identification of chromosome aneuploidy in early pregnancy is possible by using trophoblasts sorted from maternal peripheral blood, followed by FISH with chromosome specific DNA probe.