Isolation of fetal cells from the maternal circulation: Prospects for the non-invasive prenatal diagnosis

The research into non-invasive and invasive prenatal diagnostic techniques developed almost in parallel. On the one hand the need was arising to ensur e the birth of normal progeny in all cases, while on the other, it was not possible to eliminate the abortion risks connected with the invasiveness of amniocentesis (risk of abortion 1/200), chorion villi sampling, (risk of a bortion 2%) and funicolocentesis (risk of abortion 3-4%). One of the first researchers in the non-invasive field was Adinolfi who pub lished the earliest data (1) in 1974 on the possibility of detecting three types of fetal cells in the maternal circulation using flow cytometry. Adin olfi suggested the possibility of using fetal cells present in the maternal circulation for prenatal diagnosis of chromosome or biochemical anomalies. Our review takes into consideration the latest methodological and technica l progress in relation to the study of fetal cells in maternal circulation, without considering cells present in the endocervical canal where from the 8th week of pregnancy it is only possible to obtain trophoblast cells (2). This technique has since been abandoned due to the scarcity of cellular ma terial available, the greater risk of contamination by cells of maternal or igin, and also because the recovery of the cells is unpredictable, despite their potential use for the early non-invasive diagnosis of sex (3). The following issues are addressed in this review: the characterization of the fetal cell types present in the maternal circulation, the methods of th eir separation and enrichment, and the methods of genetic diagnostics appli ed.