title: Analysis of human megakaryocytic cells using dual-color immunofluorescence labeling.
abstract: BACKGROUND
  Megakaryocytes are classically identified by their cellular morphology and expression of platelet glycoproteins.
  
  
  METHODS
  In this study, the expression of GPIIIa (CD61) on hemopoietic cells was analyzed by dual-fluorescence flow cytometry.
  
  
  RESULTS
  All monocytic cells (CD14+) were shown to coexpress CD61. As the expression of platelet protein on these monocytic cells cannot be reduced by treating the cells with anticoagulant (ethlyenediaminetetraacetic acid [EDTA]), this observation is not simply due to platelet adhesion. When sorted CD61(lo)CD14+ cells were studied by light and electron microscopy, platelets or platelet fragments could not be detected on the cell surface. These cells were found to have typical monocytic morphology but no megakaryocytic characteristics.
  
  
  CONCLUSIONS
  This finding demonstrates that without careful definition, the quantitation of megakaryocytic cells will be inappropriately high. A clear and unambiguous criteria for the identification of megakaryocytic cells is described based on the high expression of platelet glycoprotein (e.g., CD61(hi) or CD41(hi)) but not the monocyte marker (CD14(neg)).
authors.affiliation: Department of Physiology, The University of Melbourne, Parkville, Victoria, Australia. hkwlaw@hkucc.hku.hk
authors.forename: H K
authors.initials: HK
authors.lastname: Law
authors.forename: S J
authors.initials: SJ
authors.lastname: Bol
authors.forename: M
authors.initials: M
authors.lastname: Palatsides
authors.forename: N T
authors.initials: NT
authors.lastname: Williams
mesh_terms: D015703:Antigens, CD / Q000032:analysis / Q000096:biosynthesis / Q000276:immunology; D001772:Blood Cell Count / Q000379:methods; D001792:Blood Platelets / Q000166:cytology / Q000648:ultrastructure; D002448:Cell Adhesion; D048429:Cell Size; D004492:Edetic Acid / Q000494:pharmacology; D005434:Flow Cytometry / Q000379:methods*; D005455:Fluorescent Antibody Technique; D006801:Humans; D016130:Immunophenotyping / Q000379:methods*; D039661:Integrin beta3; D007937:Leukapheresis; D008027:Light; D018950:Lipopolysaccharide Receptors / Q000032:analysis; D008533:Megakaryocytes / Q000166:cytology* / Q000276:immunology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D009000:Monocytes / Q000166:cytology / Q000276:immunology / Q000648:ultrastructure; D010980:Platelet Membrane Glycoproteins / Q000032:analysis / Q000096:biosynthesis / Q000276:immunology; D012542:Scattering, Radiation
chemical_list: D015703:Antigens, CD; D039661:Integrin beta3; D018950:Lipopolysaccharide Receptors; D010980:Platelet Membrane Glycoproteins; D004492:Edetic Acid