title: CD34+CDw90(Thy-1)+ subset colocated with mesenchymal progenitors in human normal bone marrow hematon units is enriched in colony-forming unit megakaryocytes and long-term culture-initiating cells.
abstract: OBJECTIVE
  The progress made in the supportive care of allografts and the identification of mesenchymal stem cells in adult human bone marrow (BM) has prompted renewed interest in the use of BM as a form of cell therapy. With the aim of optimizing the collection of BM cells, we evaluated the hematopoietic and mesenchymal immature cell contents of BM hematon units (HUs), which usually are eliminated during graft processing.
  
  
  METHODS
  Hematopoietic CD34+ progenitors from HU and buffy coat (BC) compartments were characterized in short-term culture. The sorted CD34+CDw90(Thy-1)+ primitive subset was assessed in colony-forming cell (CFC) and long-term culture-initiating cell (LTC-IC) assays, then further characterized by the expression of additional antigens. In parallel, we evaluated the colony-forming unit fibroblast (CFU-F) number and phenotyped the fresh adherent (D1-3) cells.
  
  
  RESULTS
  The plating efficiencies of CD34+ cells derived from HU and BC were identical. However, the HU CD34+CDw90(Thy-1)+ subset was enriched in colony-forming unit megakaryocyte (2.3x), LTC-IC (4.6x), and cells coexpressing CD105 (5x). We found a higher frequency of CFU-F (4.7x), considered to be the mesenchymal stem cell-containing population, correlated with an enrichment in fresh adherent (CD45/GPA)-CD14- cells.
  
  
  CONCLUSIONS
  We show for the first time that functional properties of the CD34+CDw90+ subset are related to its in vivo location in HU, which may represent the BM mesenchymal reserve compartment. The location in HU of 35.6%, 59.1%, and 58.7% of CD34+ cells, CD34+CDw90+ LTC-IC, and CFU-F, respectively, justifies the development of a procedure to collect them in order to reduce the therapeutic BM volume.
authors.affiliation: Hématologie Biologique, U.F. de Biologie et Caractérisation Cellulaires, Hématologie, Faculté de Médecine et de Pharmacie, 28 place Henri Dunant-BP 38, 63001 Clermont-Ferrand Cedex 1, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Boiret
authors.forename: Chantal
authors.initials: C
authors.lastname: Rapatel
authors.forename: Stéphane
authors.initials: S
authors.lastname: Boisgard
authors.forename: Sabine
authors.initials: S
authors.lastname: Charrier
authors.forename: Andréi
authors.initials: A
authors.lastname: Tchirkov
authors.forename: Caroline
authors.initials: C
authors.lastname: Bresson
authors.forename: Lionel
authors.initials: L
authors.lastname: Camilleri
authors.forename: Juliette
authors.initials: J
authors.lastname: Berger
authors.forename: Laurent
authors.initials: L
authors.lastname: Guillouard
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Guérin
authors.forename: Pascale
authors.initials: P
authors.lastname: Pigeon
authors.forename: Jacques
authors.initials: J
authors.lastname: Chassagne
authors.forename: Marc Gabriel
authors.initials: MG
authors.lastname: Berger
mesh_terms: D018952:Antigens, CD34 / Q000032:analysis; D001854:Bone Marrow Cells; D002452:Cell Count; D018929:Cell Culture Techniques / Q000379:methods; D002469:Cell Separation; D015672:Erythroid Precursor Cells; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology; D006801:Humans; D016130:Immunophenotyping; D008533:Megakaryocytes; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000276:immunology; D018800:Thy-1 Antigens / Q000032:analysis*
chemical_list: D018952:Antigens, CD34; D018800:Thy-1 Antigens