MATERNAL ORIGIN OF TRANSFERRIN RECEPTOR-POSITIVE CELLS IN VENOUS-BLOOD OF PREGNANT-WOMEN

We studied the origin of transferrin receptor (CD71) positive cells in blood from seven women pregnant with a male fetus in order to explore if fetal cells could be detected among them. We used a technique that allows direct chromosomal analysis by in situ hybridization on immuno logically and morphologically classified cells. Enrichment was perform ed by magnetic activated cell sorting (miniMACS)(R) using an anti-CD71 monoclonal antibody. The cells were immunophenotyped by alkaline phos phatase anti-alkaline phosphatase immunostaining with the same antibod y. The origin of the immunophenotyped cells was studied by in situ hyb ridization using an X cosmid Y repeat chromosome specific probe cockta il. CD71 positive cells were found in six of the seven women at the ra nge of 4 to 43 in respective samples. Over 90% of the CD71 positive ce lls were nucleated erythrocytes. None of the detected positive cells w ere shown to be fetal. Thus, the use of transferrin receptor antigen a lone in combination with the miniMACS(R) may not be sufficient for enr ichment of fetal cells.