title: Direct volumetric flow cytometric quantitation of CD34+ stem and progenitor cells.
abstract: OBJECTIVE
  In this study, we compared a classic single-platform (SP) method applying beads for enumeration of CD45+ or CD34+ cells with a new device allowing direct volumetric measurements of stem and progenitor cells.
  
  
  BACKGROUND
  Following apheresis and cyropreservation, the precise enumeration of CD34+ cells as key parameter of graft quality is mandatory for the clinical course after transplantation. Currently, flow cytometry with SP technique represents the 'gold standard' for such determinations.
  
  
  METHODS
  Fresh samples, 14 from mobilised peripheral blood (PB), 9 from apheresis products (AP) and 13 samples from frozen-thawed (FT) haematopoietic progenitor cell grafts, were analysed for CD34+ cells, CD45+ cells, and in frozen-thawed samples for viability by a bead-based flow cytometric method and in parallel by a direct, volumetric flow cytometric method.
  
  
  RESULTS
  Comparison of CD34+ analyses revealed a significant correlation (P < 0·01) for each material between both techniques with r = 0·95 (PB), r = 0·933 (AP) and r = 0·929 (FT). Also, for analysis of CD45+ cells µL(-1) , the measured numbers evaluated with the different techniques did not significantly differ for all three materials analysed. In frozen-thawed samples, the analysis of viability was comparable for both techniques.
  
  
  CONCLUSIONS
  The results of this study demonstrate that a direct volumetric analysis of CD34+ cells µL(-1) or CD45+ cells µL(-1) is feasible. This technique represents a simple and economical approach for standardisation of progenitor and stem cell analyses.
authors.affiliation: Institute for Transfusion Medicine, University Hospital Hamburg-Eppendorf, Germany. email@kai-gutensohn.de
authors.forename: K
authors.initials: K
authors.lastname: Gutensohn
authors.forename: A
authors.initials: A
authors.lastname: Nikolitsis
authors.forename: M
authors.initials: M
authors.lastname: Gramatzki
authors.forename: D
authors.initials: D
authors.lastname: Spitzer
authors.forename: U
authors.initials: U
authors.lastname: Buwitt-Beckmann
authors.forename: A
authors.initials: A
authors.lastname: Humpe
mesh_terms: D000328:Adult; D000368:Aged; D018952:Antigens, CD34 / Q000032:analysis*; D001772:Blood Cell Count / Q000379:methods*; D001781:Blood Component Removal; D001793:Blood Preservation; D015925:Cryopreservation; D005260:Female; D005434:Flow Cytometry / Q000295:instrumentation / Q000379:methods*; D019650:Hematopoietic Stem Cell Mobilization; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods; D006412:Hematopoietic Stem Cells / Q000737:chemistry; D006801:Humans; D017493:Leukocyte Common Antigens / Q000032:analysis; D008297:Male; D008863:Microspheres; D008875:Middle Aged; D036102:Peripheral Blood Stem Cell Transplantation / Q000379:methods; D015203:Reproducibility of Results
chemical_list: D018952:Antigens, CD34; D017493:Leukocyte Common Antigens; C516769:PTPRC protein, human