title: [In vitro study of erythroid precursors in Vaquez' disease (polycythemia vera). Evidence supporting 2 populations of erythroid stem cells in the bone marrow].
abstract: In vitro studies using the plasma clot culture system have been performed in order to compare the red cell pregenitors able to rise to erythrocytic colonies in 7 days (CFUE) in the bone marrow of polycythemia vera (PV), secondary polycythemias and normal subjects. In PV but never in normal individuals or secondary polycythemias, the bone marrow cells producing erythroid colonies without addition of erythropoietin were found. The erythropoietin dose response curves in PV is biphasic with a plateau up to a concentration of erythropoietin of 0.02--0.05 i.U./ml followed by a near normal response to erythropoietin at higher doses. Thus our results demonstrate that two populations of erythroid stem cells coexist in PV, one being abnormally sensitive to (or independent of) erythropoietin, the other normally responding to erythropoietin. After remission induced by P32 treatment, the abnormal population can disappear but the prognostic significance of this disappearance is uncertain. In the whole these results are in agreement with those of others laboratories using the plasma clot culture system. The reasons of the disagreement with the data published using the methylcellulose technic of culture are discussed.
mesh_terms: D002454:Cell Differentiation; D003114:Colony-Forming Units Assay; D004305:Dose-Response Relationship, Drug; D004900:Erythroblasts / Q000166:cytology / Q000502:physiology*; D004912:Erythrocytes / Q000502:physiology*; D004921:Erythropoietin / Q000008:administration & dosage / Q000494:pharmacology; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D006801:Humans; D011087:Polycythemia Vera / Q000473:pathology / Q000503:physiopathology*
chemical_list: D004921:Erythropoietin
vernacular_title: Etude in vitro des précurseurs érythroblastiques dans la maladie de Vaquez (polycythemia vera). arguments en faveur d'une double population de cellules souches érythroblastiques dans la moelle.