Detection of fetal trisomies 21 and 18 from maternal blood using triple gradient and magnetic cell sorting.

PROBLEM

The need for an inexpensive and reproducible technique for noninvasive prenatal diagnosis by fetal cell isolation from maternal blood.

METHOD

For enrichment of fetal cells we used a combination of triple density gradient and magnetic sorting (MACS) of (anti-CD71) transferrin receptor antibody labeled cells followed by fluorescence in situ hybridization (FISH) with chromosome-specific DNA probes for detection of fetal aneuploidies. We identified 15 cases of fetal trisomy (five cases with a trisomy 18 and ten cases with a trisomy 21) with subsequent chromosome-specific FISH.

RESULTS

We found in all of the aneuploid pregnancies that the percentage of cells with three hybridization signals did not overlap with those of normal controls independent from gestational ages and previous invasive procedures.

CONCLUSIONS

Our new approach for noninvasive prenatal diagnosis has proven to be reliable in this first series.