[In vitro autonomous growth of megakaryocytic progenitors and the role of thrombopoietin (Tpo) in essential thrombocythemia].
OBJECTIVE
To investigate in vitro autonomous growth of megakaryocytic progenitors and the role of Tpo in essential thrombocythemia (ET).


METHODS
Purified bone marrow and peripheral blood CD(34)(+) cells and nonadherent mononuclear cells (NMNC) from patients with ET were cultured to assay the spontaneous megakaryocyte colony formation. The autocrine and paracrine of Tpo in the spontaneous growth cells in liquid culture were examined by RT-PCR. The effect of Tpo on megakaryocytic progenitors was observed by addition of Tpo into CD(34)(+) cell culture.


RESULTS
There was no spontaneous CFU-MK growth in purified CD(34)(+) cell culture and spontaneous megakaryocyte colonies disappeared at NMNC cell concentrations of 10(4)/ml and 10(3)/ml. There was no Tpo expression in the spontaneous growth cells in liquid culture. Addition of Tpo to the culture of purified CD(34)(+) cells resulted in the formation of megakaryocyte colonies.


CONCLUSIONS
In vitro spontaneous CFU-MK formation in ET patients is not from autonomous growth of megakaryocyte progenitors. There is no autocrine or paracrine Tpo secretion. Megakaryocyte progenitors may be hypersensitive to Tpo or other MK-CSF.
Li
Y
Y
Department of Hematology, The First Clinical College, China Medical University, Shenyang 110001, China.
Brière
J
J
Zhai
M
M
D049109:Cell Proliferation / Q000187:drug effects*; D002478:Cells, Cultured; D006801:Humans; D055016:Megakaryocyte Progenitor Cells / Q000166:cytology* / Q000187:drug effects; D013920:Thrombocythemia, Essential / Q000503:physiopathology*; D013926:Thrombopoietin / Q000494:pharmacology*
D013926:Thrombopoietin