Multiparameter flow‐cytometrical quantitation of circulating CD34+‐cells: correlation to the quantitation of circulating haemopoietic progenitor cells by in vitro colony‐assay

Summary. A multiparameter flow-cytometrical method for the quantitation of CD34+-cells present in adult human peripheral blood cells (PBMC) has been developed. PBMC from 13 healthy adult subjects were analysed for CD34+-cells by flow-cytometry, with only the lymphoid population of cells negative for anti-CD3-moAb included in the analysis. At the same time mononuclear cells from the same individuals were depleted of CD3+- and CDl4+-cells by immunomagnetic purging. These cells were cultured for haemopoietic colonies. A correlation coefficient of 0·92 was calculated by regression analysis of CD34+-cells number versus the numbers of colonies (CFU-GM, BFU-E). Purging with anti-CD34-moAb abrogated colony-growth. The flow-cytometrical method for the determination of circulating CD34+-cells was used for the determination of circulating haemopoietic progenitor cells in one patient, in order to time leukapheresis for subsequent autologous reinfusion following high-dose chemotherapy. Determination of CD34+-cells from human adult peripheral blood by multiparameter flow-cytometry promises to be a useful tool for monitoring circulating haemopoietic progenitor cells as identified by anti-CD34-moAb.