Does long-term culture favor normal clonogenic cells from interferon-treated patients with chronic myelogenous leukemia?
We have tested whether peripheral blood mononuclear cells (PBMNCs) from interferon (IFN)-treated patients may lose residual BCR-ABL sequence-positive progenitor cells when long-term cultured for 35 days on allogeneic stromal cells. IFN-treated patients have low white blood cell counts and a fair number of BCR-ABL-negative colony-forming cells in the peripheral blood. Particularly, IFN responders show increased numbers of normal hematopoietic cells. We have quantitatively analyzed progenitor cells in PBMNCs of IFN-treated patients by combining the clonogenic assay in semisolid medium with interphase fluorescent in situ hybridization (FISH). Thus, the identification is possible of the BCR-ABL status of colony-forming progenitor cells. In IFN-treated patients, the number of BCR-ABL-positive CFCs is considerably decreased and BCR-ABL-negative CFCs appear in the peripheral blood. We could show that after LTC for 35 days of the same PBMNCs on irradiated allogeneic normal stromal cells residual BCR-ABL sequence-positive CFCs were still present. In some cases the relative number of BCR-ABL sequence-positive CFCs was found to be increased after LTC. A minor proportion of blood samples from IFN-treated patients did not give rise to CFCs after LTC on allogeneic stromal cells (three of 10 patients). Inter- and intraindividual variations can be found with regard to loss or gain of BCR-ABL sequence-positive colonies after LTC. We conclude that early CML progenitor cells persist in the peripheral blood of IFN-treated patients and that a certain proportion may survive long-term culture.
Pasternak
G
G
III Medizinische Klinik des Klinikum Mannheim, Fakultät für Klinische Medizin der Universität Heidelberg, Germany.
Schultheis
B
B
Heissig
B
B
Hörner
S
S
Sick
C
C
Hehlmann
R
R
D014408:Biomarkers, Tumor / Q000032:analysis; D001853:Bone Marrow / Q000473:pathology; D018929:Cell Culture Techniques; D018920:Coculture Techniques; D003114:Colony-Forming Units Assay; D016044:Fusion Proteins, bcr-abl / Q000032:analysis; D006412:Hematopoietic Stem Cells / Q000166:cytology*; D006801:Humans; D007155:Immunologic Factors / Q000627:therapeutic use*; D017404:In Situ Hybridization, Fluorescence; D016898:Interferon-alpha / Q000627:therapeutic use*; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000097:blood / Q000473:pathology / Q000628:therapy*; D009360:Neoplastic Cells, Circulating; D014411:Neoplastic Stem Cells / Q000166:cytology*; D017154:Stromal Cells; D013997:Time Factors; D014407:Tumor Cells, Cultured / Q000166:cytology; D014410:Tumor Stem Cell Assay
D014408:Biomarkers, Tumor; D007155:Immunologic Factors; D016898:Interferon-alpha; D016044:Fusion Proteins, bcr-abl