To the Editor.
—The article by Drs Simpson and Elias1 reviews the feasibility of using various candidate fetal cells (eg, trophoblast cells, lymphocytes, granulocytes, and erythroblasts) for prenatal genetic diagnosis. The authors consider isolation of trophoblast cells to be theoretically attractive, but stated that with regard to the use of monoclonal antibodies directed toward trophoblast, no further data have been presented since the original publication in 1990.2In our laboratory, monoclonal antibodies to trophoblast have been used in an immunomagnetic separation to isolate trophoblasts from maternal blood. Polymerase chain reaction analysis of the cell isolates correctly identified fetal sex in 13 of 14 cases.2 The cell isolates were identified as syncytiotrophoblast in a morphological study.3More recently, further evidence was presented using polymerase chain reaction analysis to detect the paternally inherited allele for β-thalassemia in trophoblast isolates from maternal blood samples.4 Inheritance was confirmed by
Hawes C, Kalionis B, Jones W. Isolating Fetal Trophoblast Cells for Prenatal Genetic Diagnosis. JAMA. 1994;271(14):1079-1080. doi:10.1001/jama.1994.03510380035026