The use of fetal cells isolated from maternal blood using different methods for prenatal diagnosis

The detection and analysis of fetal cells isolated from maternal blood is a new approach for prenatal diagnosis of chromosomal abnormalities. The pape r presents the results of diagnosis of fetal gender (sex) and fetal aneuplo idies on fetal cells, isolated from maternal blood. The fetal nucleated red blood cells (NRBCs) were isolated from the same samples using two differen t methods: by flow sorting (FACS) using antibodies against CD71-FITC, GPA-P E, Hoechst 33342, and by so called "two-step density gradient centrifugatio n" with Ficoll, 1.077 and 1.119. The fetal lymphocytes were enriched by "ai r-culturing" of maternal blood under special condition. For identification of fetal cells in all cases FISH-method with pY3.4 DNA-probe and alpha-sate llite DNA probes for chromosomes 13/21, 18 and X were used. When male fetus es were normal, the fetal Y + cells isolated from maternal blood were detec ted by FACS in 1.6 of cells; by two-step gradient centrifugation, in 3.0%; by "air culturing", in 2.7% of cells. In cases of fetal chromosomal aneuplo idies, the fetal cells showing abnormal signals with FISH were detected by FACS in 1.5-6.1% (average, 4.0%) among separated fraction, by two-step grad ient centrifugation-in 3.2-8.9% (average, 6.4%), by "air culturing"-in 1.8- 11.4% (average, 4.4%). The findings lead to conclusion that the new noninva sive approach is useful for prenatal diagnosis of chromosomal aneuploidies.