FETAL CELLS IN MATERNAL BLOOD - THE USE OF PRIMED IN-SITU (PRINS) LABELING TECHNIQUE FOR FETAL CELL DETECTION AND SEX ASSESSMENT

Prenatal diagnosis is presently performed following invasive procedure s with variable risks of fetal loss; non-invasive procedures using fet al cells in maternal blood would be welcome for the early detection of fetal sex or aneuploidy. We describe a simple and rapid protocol to d etect fetal cells and thus to assess fetal sex. In a first step, nucle ated blood cells were separated into mononuclear and polynuclear cells using a double density gradient centrifugation. In a second step prim ed in situ (PRINS) labelling technique was performed to label Y-chromo somes. 15 samples were studied and correct gender assignment was made in 13/15. The number of labelled nuclei was higher in polynuclear cell phases than in mononuclear cell phases. Moreover, the polylobular asp ect of labelled nuclei from polynuclear cell phases strongly suggested that they could belong to fetal polynuclear cells. The PRINS techniqu e combines some advantages of FISH, such as visual assessment of iii s itu chromosome labelling and the powerful specificity and sensitivity of PCR. In association with a simple enrichment procedure it constitut es a rapid protocol for fetal cell detection, non-invasive early prena tal sex assessment, and could further be applied to detect the main vi able aneuploidies. (C) 1998 John Wiley & Sons, Ltd.