title: The phenotypic profile of CD34-positive peripheral blood stem cells in different mobilization regimens.
abstract: The type of regimen used might result in mobilization of phenotypically and functionally different CD34(+) cells. We compared the phenotype of CD34(+) cells in leukapheresis products of three homogeneous groups: I, healthy individuals treated with granulocyte colony-stimulating factor (G-CSF) alone (n = 13); II, patients mobilized with G-CSF following chemotherapy (n = 16); and III, patients mobilized with G-CSF after high-dose chemotherapeutic pretreatment (n = 24). Multiparameter flow cytometry was performed for CD34(+) subpopulation analysis and focused on adhesion molecules, differentiation markers and megakaryocytic markers relevant for stem cell homing, with special reference to the importance of L-selectin expression. Regimens I and II led to higher numbers of mobilized CD34(+) cells (mean 468 x 10(6) and 491 x 10(6) CD34(+) cells per leukapheresis procedure respectively) than regimen III (mean 41 x 10(6) CD34(+) cells per leukapheresis procedure). Both the expression of L-selectin and CD54 on CD34(+) cells was significantly lower in group III, as was the percentage of megakaryocytic (CD41(+)) progenitors. A higher percentage of primitive (CD38(-) and/or HLA(-)DR(-)) CD34(+) cells was found in group III, correlating with a higher clonogenicity of the CD34(+) cells. However, when comparing the CD34(+)_ subpopulations that were also positive for L-selectin, there was no significant difference between the three regimens. A similar approach for the megakaryocytic CD34+ population resulted in an even worse quality of regimen III: 5.1% of CD34(+) being CD41(+)/L-selectin(+) compared with 9.2% and 8.9% in regimens I and II respectively. We concluded that the phenotypes of the CD34(+) cells in the G-CSF (group I) and G-CSF-chemotherapy (group II) regimens are similar, whereas the phenotype of the CD34(+) cells mobilized in the high-dose regimen (group III) displayed features that might negatively influence homing of the cells. Future studies will be directed towards regimens that will lead to the mobilization of a higher amount of CD34(+) cells with a phenotypically favourable phenotype.
authors.affiliation: Department of Medical Oncology, University Hospital Vrije Universiteit, Amsterdam, The Netherlands.
authors.forename: F
authors.initials: F
authors.lastname: de Boer
authors.forename: A M
authors.initials: AM
authors.lastname: Dräger
authors.forename: M J
authors.initials: MJ
authors.lastname: Van Haperen
authors.forename: E
authors.initials: E
authors.lastname: van der Wall
authors.forename: F
authors.initials: F
authors.lastname: Kessler
authors.forename: P C
authors.initials: PC
authors.lastname: Huijgens
authors.forename: H M
authors.initials: HM
authors.lastname: Pinedo
authors.forename: G J
authors.initials: GJ
authors.lastname: Schuurhuis
mesh_terms: D018952:Antigens, CD34 / Q000276:immunology*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy / Q000628:therapy*; D003520:Cyclophosphamide / Q000008:administration & dosage; D003907:Dexamethasone / Q000008:administration & dosage; D004317:Doxorubicin / Q000008:administration & dosage; D004334:Drug Administration Schedule; D000069585:Filgrastim; D005434:Flow Cytometry; D005472:Fluorouracil / Q000008:administration & dosage; D016179:Granulocyte Colony-Stimulating Factor / Q000494:pharmacology; D019650:Hematopoietic Stem Cell Mobilization / Q000379:methods*; D006801:Humans; D016130:Immunophenotyping; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology; D019041:L-Selectin / Q000276:immunology*; D007937:Leukapheresis; D008533:Megakaryocytes / Q000276:immunology; D008558:Melphalan / Q000008:administration & dosage; D009101:Multiple Myeloma / Q000188:drug therapy / Q000628:therapy*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000276:immunology; D011994:Recombinant Proteins; D013234:Stem Cells / Q000276:immunology*; D014750:Vincristine / Q000008:administration & dosage
chemical_list: D018952:Antigens, CD34; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D011994:Recombinant Proteins; D018799:Intercellular Adhesion Molecule-1; D019041:L-Selectin; D016179:Granulocyte Colony-Stimulating Factor; D014750:Vincristine; D003907:Dexamethasone; D004317:Doxorubicin; D003520:Cyclophosphamide; D000069585:Filgrastim; D008558:Melphalan; D005472:Fluorouracil