Flt-3 ligand does not induce the growth of peripheral blood granulocyte-macrophage colony-forming cells in myeloproliferative disorders.
Flt-3 ligand (FL) is a growth factor (GF) which might have clinical use as a mobilizer of stem and progenitor cells into peripheral blood (PB) in autologous transplantations of various malignant haematological diseases, unless FL stimulates the growth of malignant cells in these diseases. The present study evaluated the effects of FL on the proliferation of granulocytemacrophage (GM) progenitor cells collected from PB of 24 patients with chronic myeloproliferative disorders (MPDs) by using a methylcellulose assay in serum-free culture conditions. It was shown that FL as a single factor had no stimulatory effect on GM colony formation either in the whole MPD group or in the MPD subgroups, which comprised 9 patients with essential thrombocythaemia, 7 with polycythaemia vera and 8 with chronic myelogenous leukaemia. No increase in GM colony formation was observed, either, when FL was used in combination with other GFs, such as mast cell growth factor (MGF), granulocyte-colony stimulating factor (G-CSF), GM-CSF or interleukin-3 (IL-3). GM-CSF and IL-3 were the only single GFs which significantly increased GM colony formation in the whole MPD group. As a conclusion, FL does not seem to induce GM colony formation of MPDs alone or in combination with G-CSF in in vitro colony assays.
Siitonen
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Department of Internal Medicine, University of Oulu, Finland. timo.siitonen@na.netppl.fi
Savolainen
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ER
Koistinen
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D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002454:Cell Differentiation / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D005260:Female; D006098:Granulocytes / Q000473:pathology*; D006412:Hematopoietic Stem Cells / Q000187:drug effects / Q000473:pathology*; D006801:Humans; D008024:Ligands; D008264:Macrophages / Q000473:pathology*; D008297:Male; D008565:Membrane Proteins / Q000494:pharmacology*; D008875:Middle Aged; D009196:Myeloproliferative Disorders / Q000097:blood / Q000473:pathology*
D008024:Ligands; D008565:Membrane Proteins; C084881:flt3 ligand protein