title: CD34+ cells from first-trimester fetal blood are enriched in primitive hemopoietic progenitors.
abstract: OBJECTIVE
  The purpose of this study was to investigate whether purified CD34(+) cells from first-trimester fetal blood are a source of primitive and committed hemopoietic progenitors.
  
  
  METHODS
  CD34(+) cells from first-trimester fetal blood and term cord blood were assayed for committed hemopoietic progenitor cells, high proliferative potential colony-forming cells, and long-term culture-initiating cells.
  
  
  RESULTS
  First-trimester CD34(+) cells that were compared with cells at term generated fewer hemopoietic progenitor cells and fewer high proliferative potential colony-forming cells with lower recloning efficiency(P <.001). First-trimester CD34(+) cells tended to contain more long-term culture-initiating cells, both in bulk cultures and by limiting dilution analysis. The ratio between committed and primitive progenitors was 3 in the first-trimester and 20 in the term cord blood, respectively.
  
  
  CONCLUSIONS
  First-trimester fetal blood is enriched in primitive (compared with committed) hemopoietic progenitors and may be an advantageous source of stem cells for prenatal therapy.
authors.affiliation: Wolfson and Weston Research Centre for Family Health, Institute of Reproductive and Developmental Biology, London, United Kingdom.
authors.forename: Angelo
authors.initials: A
authors.lastname: Tocci
authors.forename: Irene A G
authors.initials: IA
authors.lastname: Roberts
authors.forename: Sailesh
authors.initials: S
authors.lastname: Kumar
authors.forename: Phillip R
authors.initials: PR
authors.lastname: Bennett
authors.forename: Nicholas M
authors.initials: NM
authors.lastname: Fisk
mesh_terms: D018952:Antigens, CD34 / Q000032:analysis*; D001773:Blood Cells / Q000166:cytology* / Q000276:immunology*; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay; D005260:Female; D005312:Fetal Blood; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D013997:Time Factors
chemical_list: D018952:Antigens, CD34