title: Ex vivo expansion of mafosfamide-purged PBPC products.
abstract: BACKGROUND
  Multiple studies have demonstrated that 'purging' of autografts with 4-hydroperoxycyclophosphamide (4HC) or the related compound mafosfamide (Mf), to eradicate residual leukemia, produces the best results associated with autologous blood and marrow transplantation for AML. However, 4HC purging results in prolonged aplasia. Therefore, we evaluated the potential of ex vivo expansion of Mf-treated CD34+ cells from mobilized PBPC.
  
  
  METHODS
  CD34+ cells were isolated from PBPC products and treated with 30 microg/mL Mf. The Mf-treated CD34+ cells were washed and cultured for 14 days in StemLine II-defined media containing recombinant human (rh) SCF, G-CSF and thrombopoietin (Tpo).
  
  
  RESULTS
  Treatment with Mf resulted in 90% killing of progenitor cells (GM-CFC) but maintenance of SCID-repopulating cells (SRC). Ex vivo culture of the Mf-treated CD34+ cells resulted in decreased cell numbers (10-20% of the starting cell dose) during the first week. Nevertheless, in the second week of culture the total cell numbers expanded to approximately 20-fold above starting cell numbers and progenitor cells returned to approximately pre-treatment levels.
  
  
  CONCLUSIONS
  These studies demonstrate the potential of ex vivo culture to expand both total cell numbers and progenitor cells following treatment of PBPC CD34+ cells with Mf. Clinical studies are currently being initiated to evaluate the engraftment potential of these purged and expanded products.
authors.affiliation: Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University, Baltimore, Maryland 21231, USA. imcniec1@jhmi.edu
authors.forename: I
authors.initials: I
authors.lastname: McNiece
authors.forename: C
authors.initials: C
authors.lastname: Civin
authors.forename: J
authors.initials: J
authors.lastname: Harrington
authors.forename: J
authors.initials: J
authors.lastname: Kellner
authors.forename: M
authors.initials: M
authors.lastname: Malehorn
authors.forename: J
authors.initials: J
authors.lastname: Turney
authors.forename: J
authors.initials: J
authors.lastname: Barber
authors.forename: R
authors.initials: R
authors.lastname: Jones
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D018952:Antigens, CD34; D016465:Bone Marrow Purging; D002478:Cells, Cultured; D003520:Cyclophosphamide / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D006412:Hematopoietic Stem Cells; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000628:therapy*; D051379:Mice; D016513:Mice, SCID; D036102:Peripheral Blood Stem Cell Transplantation; D014182:Transplantation, Autologous; D014183:Transplantation, Heterologous
chemical_list: D000276:Adjuvants, Immunologic; D018952:Antigens, CD34; C048341:mafosfamide; D003520:Cyclophosphamide