Use of Annexin V for the Identification of Fetal Cells in Maternal Circulation

Abstract

MACS with Annexin V-conjugated microbeads was used to isolate cells in apoptosis from the peripheral blood of 112 women at different weeks of gestation and from 15 women (60 samples) sequentially tested postpartum. FISH using X/Y probes was applied to quantitate fetal apoptotic cells. The mean apoptosis rate in the 16th-18th week was 6.5% and fetal cells constituted 5.1% of the apoptotic cell population. In the 26th-28th week it was 10.1%/7.5% and in the 37th-38th week 12.5%/9.9%, respectively. In samples obtained 30 min, 12h and 24h postpartum, the mean apoptosis was 25.1%, 12.5 and 6.1%, respectively and fetal cells constituted 14.8%, 2.1% and 0.16% of the apoptotic cells. Forty-eight h after delivery, apoptosis was 2.3% and no fetal cells were detected. Accurate estimation of the proportion of fetal cells undergoing apoptosis may facilitate the optimization of protocols for non-invasive prenatal diagnosis of chromosomal abnormalities.