Electronic volume of CD34 positive cells from peripheral blood apheresis samples

Background: The authors have used a flow analyzer to measure electronic cellular volume of peripheral blood hematopoietic stem/progenitor cells obtained by granulocyte‐colony stimulating factor (G‐CSF) mobilization and apheresis (HPC‐A) of patients with hematological malignancies. Methods: Fifty three apheresis samples stained with CD45‐fluorescein isothiocyanate (FITC) and CD34‐R‐phycoerythrin (PE)‐labeled antibodies after erythrocyte lysis with BD FACS™ Lysing Solution were analyzed for electronic cell volume and two‐color FITC and PE fluorescence. Results: Lymphocytes, monocytes and granulocytes in the HPC‐A samples had a mean electronic volume of 414, 797, and 670 μm 3 , respectively corresponding to cell diameter of 9.25, 11.5, and 10.85 μm. In 53 HPC‐A samples analyzed, the mean electronic volume of the CD34 positive mononuclear cells was 407 μm 3 while the CD45 positive cells had mean volume of 453 μm 3 . Conclusions: CD34 positive stem/progenitor cells have a smaller volume and diameter than CD45 positive mononuclear cells in HPC‐A samples. In the present study the CD34 stem/progenitor cells had a considerably larger diameter than that of stem cells previously reported in the literature. With the availability of electronic cell volume as a parameter in flow cytometric analysis, further studies can be carried out to correlate stem cell volume with specific phenotypic marker expression. © 2008 Clinical Cytometry Society