title: Ex vivo expansion of normal progenitor cells from acute myeloid leukemia cell-contaminated CD34+ peripheral blood progenitor cells after mafosfamide purging.
abstract: The rationale for purging of autologous acute myeloid leukemia (AML) grafts is to eradicate contaminating leukemic cells that might contribute to relapse. However, in vitro purging generally delays post-transplant hematopoietic recovery, thus increasing treatment-related complication rates. Theoretically, this prolonged aplasia might be shortened by the additional transplantation of ex vivo-generated progenitor cells. Therefore, we investigated whether nonleukemic progenitors could be expanded ex vivo from AML cell-contaminated CD34(+) peripheral blood progenitor cell (PBPC) preparations. Nonleukemic CD34(+)-selected PBPC and AML cells (Kasumi-1, KG-1, primary AML blasts) were cultured in cytokine-supplemented liquid culture for up to 19 days. Cells were used either unmanipulated or following in vitro purging with mafosfamide (30, 50, 75 microg/ml). Ex vivo-generated cells were assessed by flow cytometry, progenitor cell assays, and polymerase chain reaction. Without prior purging, ex vivo culture markedly amplified AML cells as well as nonleukemic CD34(+) PBPC (day 12: Kasumi-1, 18.5 +/- 0.6-fold; KG-1, 52.2 +/- 2.6-fold; CD34(+), 74.1 +/- 5.6-fold). Co-culture with leukemic cells did not affect CD34(+) cell growth and vice versa. Following in vitro purging, CD34(+) PBPC were expanded even at the highest mafosfamide dose (day 19: 25 +/- 15-fold), whereas leukemic cells were markedly depleted (approx. 1.5 log). Furthermore, normal colony-forming units (CFU) could be effectively recovered (day 19: 10 +/- 3.1% of prepurging input CFU), whereas CFU-L were depleted to undetectable levels in six of seven experiments. Finally, leukemic cells were undetectable following ex vivo co-culture of purged cells (CD34(+) PBPC plus 10% Kasumi-1 cells or primary blasts), but were clearly detectable without purging. Taken together, these data demonstrated that ex vivo expansion of normal progenitors from mafosfamide-purged AML cell-contaminated grafts might be feasible.
authors.affiliation: Department of Internal Medicine, Hematology, Oncology, Immunology and Rheumatology, University of Tübingen, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Stilz
authors.forename: F
authors.initials: F
authors.lastname: Grünebach
authors.forename: P
authors.initials: P
authors.lastname: Bader
authors.forename: W
authors.initials: W
authors.lastname: Vogel
authors.forename: L
authors.initials: L
authors.lastname: Kanz
authors.forename: W
authors.initials: W
authors.lastname: Brugger
authors.forename: S
authors.initials: S
authors.lastname: Scheding
mesh_terms: D000208:Acute Disease; D018952:Antigens, CD34; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001773:Blood Cells / Q000166:cytology / Q000276:immunology; D016465:Bone Marrow Purging / Q000379:methods*; D002455:Cell Division / Q000187:drug effects; D018920:Coculture Techniques; D003520:Cyclophosphamide / Q000031:analogs & derivatives* / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects; D006801:Humans; D007951:Leukemia, Myeloid / Q000473:pathology*; D014411:Neoplastic Stem Cells / Q000166:cytology / Q000187:drug effects
chemical_list: D018952:Antigens, CD34; D000970:Antineoplastic Agents; C048341:mafosfamide; D003520:Cyclophosphamide