Fetal cell identifiers: Results of microscope slide-based immunocytochemical studies as a function of gestational age and abnormality

OBJECTIVE: We evaluated monoclonal antibodies to 3 cell surface and 3 intra cellular antigens for their relative usefulness as markers to identify feta l cells in maternal blood. STUDY DESIGN: With indirect immunocytochemical labeling techniques, antigen expression was studied in 52 fetal blood samples as a function of gestatio nal age, fetal karyotype, the presence of multiple anomalies detectable on ultrasonography, and anemia. RESULTS: A decline in the expression of these antigens as gestational age a dvanced was demonstrated. Samples from karyotypicaily abnormal fetuses, fet uses with multiple anomalies, and anemic fetuses showed an antigenic distri bution that was immature for gestational age. In normal fetuses zeta globin and epsilon globin expression decreased after 12 to 14 weeks, potentially limiting the utility of these proteins as fetal cell markers in the isolati on of fetal cells from maternal blood. CONCLUSIONS: The results of this study demonstrate a fetal developmental he matologic profile that varies with gestational age and also with pathologic condition. Antibodies to the gamma chain of fetal hemoglobin and the trans ferrin receptor (CD71) are the most useful fetal cell-identifying reagents. (Am J Obstet Gynecol 1999;180:1234-9.).