Enrichment and detection of fetal erythroid cells from maternal peripheralblood using liquid culture

Isolating fetal cells from maternal blood for prenatal genetic analysis is the least invasive method currently being investigated. In order to enrich these fetal erythroid cells we employed a two-phase liquid culture system t hat supports the growth and differentiation of erythroid progenitor cells. Mononuclear cells were separated from ten maternal blood samples at 8-14(+3 ) weeks of gestation and cultured in the first phase. After 4-5 days, the n on-adherent cells were harvested and recultured with erythropoietin for ano ther 3-4 days. The mean number of rotal erythroid cells reached approximate ly 0.77 x 10(6)/ml with an average purity of 90.5%. Hb F stain disclosed fe tal erythroid cells averaging similar to5.7%. therefore the mean number of fetal erythroid cells isolated was 0.49 x 10(5)/ml. Female karyotypes were only observed while counting 5-66 metaphases. However, male DNA (SRY or DYZ 1) was detected by PCR in 7/10 cases; in four of these cases and in one SRY -negative pregnancy the 46,XY karyotype: was Found by amniocentesis perform ed during the second trimester. This liquid culture system provided an enri ched source of fetal cells without the need for more complicated separation or sorting procedures. Copyright (C) 2001 John Wiley & Sons, Ltd.