A new marker set that identifies fetal cells in maternal circulation with high specificity.

Objective Fetal cells from the maternal circulation (FCMBs) have the potential to replace cells from amniotic fluid or chorionic villi in a diagnosis of common chromosomal aneuploidies. Good markers for enrichment and identification are lacking. Method Blood samples from 78 normal pregnancies were used for testing the marker-set CD105 and CD141 for fetal cell enrichment. Fetal cell candidates were subsequently stained by a cocktail of cytokeratin antibodies, and the gender of the fetal cells was explored by fluorescence in situ hybridization (FISH) of the X and Y chromosomes. Results Fetal cell candidates could be detected in 91% of the samples, and in 85% of the samples, it was possible to obtain X and Y chromosomal FISH results for gender determination. The concordance between gender determined by FISH on fetal cells in maternal blood and gender found at birth reached 100% if three or more fetal cells with FISH signals could be found in a sample. Conclusion The marker set identifies fetal cells with specificity high enough to make cell-based noninvasive prenatal diagnosis realistic. © 2014 John Wiley & Sons, Ltd. Funding sources: The experiments described in this article were funded by the private company FCMB ApS. The ultimate goal of FCMB ApS was to develop a new method for noninvasive prenatal diagnostics based on identification of fetal cells in the maternal circulation. Conflicts of interest: The experiments described in this article were performed in the private company FCMB ApS in which the authors MB, RS, LH, KM, RHL, and BC were employed. SK and BC are founders of this company. The authors MB, RS, LH, BC, and SK have filed patent applications on the isolation and identification of fetal cells in maternal blood for noninvasive prenatal diagnostics.