Comparison of Cytokine Efficacy on Ex Vivo Expansion of Megakaryocyte (MK) Progenitor Cells between Essential Thrombocythemia (ET) and Normal Person.

Essential thrombocythemia (ET) is a chronic myeloproliferative disorder (MPD) of insidious onset and characterized by regulatory defect in stem cells. It is possible that ET can induce autonomous megakaryocyte (MK) growth. The physiology of megakaryocytopoiesis was not well defined, and, as a consequence, the pathophysiology of ET characterized by excessive platelet production was poorly understood. Secondary thrombocytopenia, especially post-transplantation, could be fatal so there were many trials to overcome this problem. This experiment was designed to test the effect of cytokines on ex vivo expansion of MK progenitor cells from ET. The MK colony forming unit (CFU-MK) expansion degree according to single or combination cytokines were analyzed in normal person and ET patients. Mononuclear cells were isolated from bone marrow aspiration and then cultured in serum-free medium (MegaCult^™) supplemented with SCF, G-CSF, TPO, IL-11 and 3 types of cytokine combination. After 14 days of ex vivo expansion and then the CFU-MK were counted by microscope. In the absence of cytokines, CFU-MK of ET significantly expanded than normal (p<0.05), which represented autonomous CFU-MK formation. There were significantly increased mixed CFU-MK of ET in SCF, G-CSF and TPO (SGT) combined cytokine added well (p<0.05) but pure and total CFU-MK of SGT added well did not show significant expansion. When the effect of cytokines were compared between normal and ET, all of the cytokines significantly expand CFU-MK in ET (p<0.05) than normal and especially in pure CFU-MK. In summary, autonomous MK growth was shown in ET and SGT can be relatively effective cytokine combinations in ex vivo CFU-MK expansion. Further investigation will be needed to find out the most effective culture system and cytokine combination for ex vivo MK progenitor expansion.