title: Evaluation of 'out-of-specification' CliniMACS CD34-selection procedures of hematopoietic progenitor cell-apheresis products.
abstract: BACKGROUND
  Immunomagnetic selection of CD34(+) hematopoietic progenitor cells (HPC) using CliniMACS CD34 selection technology is widely used to provide high-purity HPC grafts. However, the number of nucleated cells and CD34+ cells recommended by the manufacturer for processing in a single procedure or with 1 vial of CD34 reagent is limited.
  
  
  METHODS
  In this retrospective evaluation of 643 CliniMACS CD34-selection procedures, we validated the capacity of CliniMACS tubing sets and CD34 reagent. Endpoints of this study were the recovery and purity of CD34+ cells, T-cell depletion efficiency and recovery of colony-forming units-granulocyte-macrophage (CFU-GM).
  
  
  RESULTS
  Overloading normal or large-scale tubing sets with excess numbers of total nucleated cells, without exceeding the maximum number of CD34+ cells, had no significant effect on the recovery and purity of CD34+ cells. In contrast, overloading normal or large-scale tubing sets with excess numbers of CD34+ cells resulted in a significantly lower recovery of CD34+ cells. Furthermore, the separation capacity of 1 vial of CD34 reagent could be increased safely from 600 x 10(6) CD34+ cells to 1000 x 10(6) CD34+ cells with similar recovery of CD34(+) cells. Finally, T-cell depletion efficiency and the fraction of CD34+ cells that formed CFU-GM colonies were not affected by out-of-specification procedures.
  
  
  CONCLUSIONS
  Our validated increase of the capacity of CliniMACS tubing sets and CD34 reagent will reduce the number of selection procedures and thereby processing time for large HPC products. In addition, it results in a significant cost reduction for these procedures.
authors.affiliation: Department of Hematology, Erasmus University Medical Center, Rotterdam, the Netherlands. e.braakman@erasmusmc.nl
authors.forename: E
authors.initials: E
authors.lastname: Braakman
authors.forename: G J
authors.initials: GJ
authors.lastname: Schuurhuis
authors.forename: F W M B
authors.initials: FW
authors.lastname: Preijers
authors.forename: C
authors.initials: C
authors.lastname: Voermans
authors.forename: K
authors.initials: K
authors.lastname: Theunissen
authors.forename: I
authors.initials: I
authors.lastname: van Riet
authors.forename: W E
authors.initials: WE
authors.lastname: Fibbe
authors.forename: I
authors.initials: I
authors.lastname: Slaper-Cortenbach
mesh_terms: D018952:Antigens, CD34 / Q000276:immunology*; D005434:Flow Cytometry; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000276:immunology*; D006801:Humans; D007937:Leukapheresis / Q000191:economics / Q000295:instrumentation / Q000379:methods*; D008212:Lymphocyte Depletion; D015203:Reproducibility of Results; D012189:Retrospective Studies
chemical_list: D018952:Antigens, CD34