title: CD34+CD38- is a good predictive marker of cloning ability and expansion potential of CD34+ cord blood cells.
abstract: BACKGROUND
  Ex vivo expansion of HPCs is an attractive approach to overcoming the current limitations of human cord blood transplantation. It is important not only to define the optimal culture conditions but also to know the number of progenitor cells that can be obtained. CD34+ cells have a great variability in their cloning capacity and in their ability to expand HPCs. This study was carried out to assess whether this variability could be due to intrinsic or extrinsic factors.
  
  
  METHODS
  CD34+ cells were analyzed for the expression of CD38, CD133, and CD117 and cultured in serum-free culture medium with four cytokine combinations: SCF plus thrombopoietin plus flt3 ligand (STF), STF plus IL-3, STF plus IL-6, and STF plus IL-6 plus IL-3. After a 1-week culture, the numbers of CD34+ cells and CFUs were determined.
  
  
  RESULTS
  The variability observed both in the cloning ability of CD34+ isolated cells and in their expansion capacity was inversely related to the frequency of the more immature CD34+CD38- cells. When more mature CD34+CD38+ cells were present within CD34+-isolated cells, a higher cloning ability, measured as CFUs, and a higher expansion capacity were observed.
  
  
  CONCLUSIONS
  Enumeration of CD34+CD38- cells is correlated with the number of committed progenitors and the capacity of generating CD34+ cells, an important parameter if expansion protocols must be used in clinical transplantation.
authors.affiliation: Institute of Cell Biology, Valencia Public Organism of Investigation, Spain.
authors.forename: Araceli
authors.initials: A
authors.lastname: Encabo
authors.forename: Emilia
authors.initials: E
authors.lastname: Mateu
authors.forename: Francisco
authors.initials: F
authors.lastname: Carbonell-Uberos
authors.forename: María Dolores
authors.initials: MD
authors.lastname: Miñana
mesh_terms: D000071916:AC133 Antigen; D036541:ADP-ribosyl Cyclase / Q000032:analysis*; D051997:ADP-ribosyl Cyclase 1; D015703:Antigens, CD / Q000032:analysis*; D018952:Antigens, CD34 / Q000032:analysis*; D015415:Biomarkers / Q000032:analysis*; D002452:Cell Count; D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D002999:Clone Cells; D003114:Colony-Forming Units Assay; D005312:Fetal Blood / Q000166:cytology*; D005434:Flow Cytometry; D006023:Glycoproteins / Q000032:analysis; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D008562:Membrane Glycoproteins; D010455:Peptides / Q000032:analysis; D019009:Proto-Oncogene Proteins c-kit / Q000032:analysis
chemical_list: D000071916:AC133 Antigen; D015703:Antigens, CD; D018952:Antigens, CD34; D015415:Biomarkers; D006023:Glycoproteins; D008562:Membrane Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides; D019009:Proto-Oncogene Proteins c-kit; D036541:ADP-ribosyl Cyclase; C498154:CD38 protein, human; D051997:ADP-ribosyl Cyclase 1