title: A novel method of CD34+ cell separation from umbilical cord blood.
abstract: BACKGROUND
  Umbilical cord blood (UCB) is rich in the heavily glycosylated CD34 antigen-bearing hematopoietic stem cells that are valuable for transplantation therapy of malignant and nonmalignant disease. CD34+ cell yields (0.13%-0.25%-0.3%) of mononuclear cells (UCMCs) isolated by anti-CD34 monoclonal antibody (MoAb) on immunomagnetic particles (e.g., Miltenyi particles) are insufficient to treat adults.
  
  
  METHODS
  We fractionated UCMCs by physicochemical charge-based methods. Avoiding Miltenyi particles and HESPAN yielded 30 x 10(6) to 54 x 10(6) UCMCs/20 mL UCB by Ficoll-Isopaque for serial depletion fractionation, using nylon wool column (NWC) or direct rosetting with sheep red blood cells (SRBCs) without incubation in the cold.
  
  
  RESULTS
  CD34+ cell yields (approx. 5.12%) were 39 times greater than 0.13% (Korean study, 11,098 UCB units) and 10 to 20 times greater than 0.25% to 0.3% harvested by anti-CD34 Miltenyi particles. SRBC depletion of most high-specific-gravity T cells achieved considerable enrichment of CD34+ and BY55+ cells. Using NWC achieved 2.5-fold enrichment of CD34+ cells and twofold enrichment of BY55+ cells. Direct SRBC rosetting provided better or higher enrichment of CD34+ cells. Overall CD34+ cell yield in low-density fraction was more than twice after direct rosetting (38% vs. 16%) in contrast to separation by NWC followed by SRBC rosetting. CD3+ cell yields (by three CD markers) were approximately 8.83%, far below approximately 30 x 10(7) /kg considered acceptable to avoid graft-versus-host disease. Natural killer cell yields (CD16+/CD56+ and BY55+/ CD160+) are in perfect agreement.
  
  
  CONCLUSIONS
  Achieving approximately 5% CD34+ cell yields from single UCB donations, a major advance, holds great promise for CD34+ cell therapy of adults and larger children, and cheaper cultured RBC manufacture.
authors: University of Cambridge, Cambridge, UK; Department of Probability, Alfréd Rényi Mathematical Institute of The Hungarian Academy of Sciences, 1053, Budapest, Hungary.
authors: J N
authors: JN
authors: Mehrishi
authors: Tibor
authors: T
authors: Bakács
mesh_terms: D018952:Antigens, CD34 / Q000032:analysis*; D002469:Cell Separation / Q000379:methods*; D036101:Cord Blood Stem Cell Transplantation; D005312:Fetal Blood / Q000737:chemistry / Q000166:cytology*; D006412:Hematopoietic Stem Cells / Q000737:chemistry / Q000166:cytology*; D006801:Humans
chemical_list: D018952:Antigens, CD34