title: Identification of BCR/ABL-negative primitive hematopoietic progenitor cells within chronic myeloid leukemia marrow.
abstract: Chronic myeloid leukemia (CML) is a malignant disorder of the hematopoietic stem cell. It has been shown that normal stem cells coexist with malignant stem cells in the bone marrow of patients with chronic-phase CML. To characterize the primitive hematopoietic progenitor cells within CML marrow, CD34+DR- and CD34+DR+ cells were isolated using centrifugal elutriation, monoclonal antibody labeling, and flow cytometric cell sorting. Polymerase chain reaction analysis of RNA samples from these CD34+ subpopulations was used to detect the presence of the BCR/ABL translocation characteristic of CML. The CD34+DR+ subpopulation contained BCR/ABL(+) cells in 11 of 12 marrow samples studied, whereas the CD34+DR- subpopulation contained BCR/ABL(+) cells in 6 of 9 CML marrow specimens. These cell populations were assayed for hematopoietic progenitor cells, and individual hematopoietic colonies were analyzed by PCR for their BCR/ABL status. Results from six patients showed that nearly half of the myeloid colonies cloned from CD34+DR- cells were BCR/ABL(+), although the CD34+DR- subpopulation contained significantly fewer BCR/ABL(+) progenitor cells than either low-density bone marrow (LDBM) or the CD34+DR+ fraction. These CD34+ cells were also used to establish stromal cell-free long-term bone marrow cultures to assess the BCR/ABL status of hematopoietic stem cells within these CML marrow populations. After 28 days in culture, three of five cultures initiated with CD34+DR- cells produced BCR/ABL(-) cells. By contrast, only one of eight cultures initiated with CD34+DR+ cells were BCR/ABL(-) after 28 days. These results indicate that the CD34+DR- subpopulation of CML marrow still contains leukemic progenitor cells, although to a lesser extent than either LDBM or CD34+DR+ cells.
authors.affiliation: Department of Medicine, Indiana University School of Medicine, Indianapolis 46202.
authors.forename: T
authors.initials: T
authors.lastname: Leemhuis
authors.forename: D
authors.initials: D
authors.lastname: Leibowitz
authors.forename: G
authors.initials: G
authors.lastname: Cox
authors.forename: R
authors.initials: R
authors.lastname: Silver
authors.forename: E F
authors.initials: EF
authors.lastname: Srour
authors.forename: G
authors.initials: G
authors.lastname: Tricot
authors.forename: R
authors.initials: R
authors.lastname: Hoffman
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000032:analysis; D018952:Antigens, CD34; D014408:Biomarkers, Tumor / Q000032:analysis*; D001853:Bone Marrow / Q000473:pathology*; D003114:Colony-Forming Units Assay; D005434:Flow Cytometry; D016044:Fusion Proteins, bcr-abl / Q000032:analysis*; D006684:HLA-DR Antigens / Q000032:analysis; D006412:Hematopoietic Stem Cells / Q000473:pathology*; D006801:Humans; D016130:Immunophenotyping; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000473:pathology*; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D014178:Translocation, Genetic
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D014408:Biomarkers, Tumor; D006684:HLA-DR Antigens; D016044:Fusion Proteins, bcr-abl