Direct detection of fetal cells in maternal blood: a reappraisal using a combination of two different Y chromosome-specific FISH probes and a single X chromosome-specific probe.
BACKGROUND
We have recently explored the detection of circulatory male fetal cells directly in maternal whole blood samples by fluorescence in-situ hybridization (FISH). In order to improve the efficacy of fetal cell detection, we have now examined whether this could be enhanced by the use of two different Y chromosome-specific FISH probes (alpha-satellite and classical satellite III regions) in combination with an X chromosome-specific FISH probe.


METHODS
Nineteen maternal blood samples (median gestational age = 28 weeks, range = 12-37 weeks) were examined in a blinded manner. No enrichment procedure was performed. Following hypotonic treatment and Carnoy's fixation, total nucleated cells were examined by two color FISH with a single X and two Y chromosome-specific probes. Nine cases were examined in parallel by conventional XY-FISH.


RESULTS
Fetal cell detection was superior when using two Y chromosome-specific probes (specificity = 75%; sensitivity = 91%) when compared to the conventional XY-FISH approach (specificity = 50%; sensitivity = 60%).


CONCLUSIONS
Male fetal cells can be detected in most maternal blood samples examined. Specificity and sensitivity is improved when using a combination of single X and two Y chromosome-specific probes when compared to a conventional XY-FISH protocol.
Babochkina
Tatiana
T
Laboratory for Prenatal Medicine, University Women's Hospital/Department of Research, Spitalstr. 21, 4031, Basel, Switzerland.
Mergenthaler
Susanne
S
Dinges
Tatyana Maier
TM
Holzgreve
Wolfgang
W
Hahn
Sinuhe
S
D041321:Chromosomes, Human, X; D041322:Chromosomes, Human, Y; D005260:Female; D005333:Fetus / Q000166:cytology*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D011237:Predictive Value of Tests; D011247:Pregnancy / Q000097:blood; D011262:Pregnancy Trimester, Second / Q000097:blood; D011263:Pregnancy Trimester, Third / Q000097:blood; D011296:Prenatal Diagnosis; D012680:Sensitivity and Specificity