The use of transferrin for enrichment of fetal cells from maternal blood

Iron loaded transferrin (holotransferrin) was used for enrichment of fetal cells from peripheral blood of pregnant women. Cord blood samples were used to evaluate enrichment efficacy of single and double MACS separations. Blood samples were obtained from 10 pregnant women prior to chorion villus sampling (CVS). Erythroblasts and other mononuclear cells were isolated by triple-density gradient centrifugation. Fetal cells were further enriched by positive magnetic sorting (VarioMACS) using biotinylated transferrin and streptavidin conjugated to magnetic microbeads. The isolated cells were analysed with dual-colour in situ hybridization (FISH) with X- and Y-chromosome specific probes. Male fetuses were correctly identified in three out of four (75%) pregnancies and female fetuses in six out of six (100%) pregnancies. By using transferrin instead of antibodies to the transferrin receptor to label and enrich fetal cells, we believe that unspecific binding attributed to immunological labelling can be minimized. The results indicate that transferrin may be an alternative to antibodies to transferrin receptor for separation of fetal cells from maternal blood.