FETAL CELLS IN THE PERIPHERAL-BLOOD OF PREGNANT-WOMEN EXPRESS THYMIDINE KINASE - A NEW MARKER FOR DETECTION

Petal cells occur in maternal blood in a substantial proportion of nor mal pregnancies. Several different approaches have been used to detect and enrich these cells for non-invasive prenatal diagnosis. However, before these fetal cells can routinely be used for prenatal diagnosis, perfectly reproducible procedures for detection and enrichment need t o be established. We found that these fetal cells express high intrace llular levels of the DNA precursor pathway enzyme thymidine kinase. Si nce normal adult peripheral blood cells do not exhibit any thymidine k inase activity, this enzyme is a potent new marker to detect and enric h fetal cells from maternal blood. We further describe the first succe ssful application of a cytofluorometric thymidine kinase assay to dete ct fetal cells in the maternal circulation by virtue of their high thy midine kinase activity. (C) 1997 Federation of European Biochemical So cieties.