A comparison of the choice of monoclonal antibodies for recovery of fetal cells from maternal blood using FACS for noninvasive prenatal diagnosis of hemoglobinopathies.

BACKGROUND: Isolation of adequate numbers of fetal cells circulating in the maternal circulation is the major hurdle in developing noninvasive prenatal diagnostic procedures. We used flow cytometry and a combination of different monoclonal antibodies to compare the yield and purity of the fetal nucleated red blood cells at different periods of gestation.
METHODS: Using a Percoll discontinuous gradient, the fetal nucleated erythrocytes were enriched from 7 ml maternal blood. In 100 samples, the enriched cells were stained with CD45, anti-fetal hemoglobin, and glycophorin A antibodies and in 30 samples they were stained with CD45, anti-fetal hemoglobin, and CD71 and then sorted and used for fetal diagnosis of hemoglobinopathies.
RESULTS: Using the first set of antibodies, although we were able to obtain a higher percentage of fetal nucleated red cells (0.07% +/- 0.2%) as compared to the second set which yielded comparatively smaller numbers (0.025% +/- 0.03%), there was some compromise in purity.
CONCLUSION: Using CD45, anti-fetal hemoglobin and CD71 would be preferred as minimizing maternal contamination is more important than yield for prenatal diagnosis. (c) 2008 Clinical Cytometry Society.