[Ex vivo expansion of megakaryocytic progenitors from mobilized human peripheral blood]

This study was aimed to investigate the effect of some culture system composed of various cytokine combinations (TPO, SCF, FL, IL-1, IL-3, IL-6) on ex vivo expansion of megakaryocytic progenitors induced from CD34+ cells of peripheral blood and to seek a optimal cytokine combination and culture time. Mononuclear cells were isolated from mobilized peripheral blood (MPB) by density gradient centrifugation over Ficoll. CD34+ cells were purified by using an immunomagnetic bead separation system. The selected CD34+ cells were seeded in Iscove's modified Kulbecco's medium (IMDM) supplemented with fetal calf serum (FCS) and various kinds of cytokines. After 15 days of culture, the content of CD41+ cells in culture system were determined by flow cytometry, and the number of megakaryocyte colony-forming unit (CFU-MK) was measured simultaneously. The results showed that after definited days of culture, the cytokine combination TPO/FL/IL-6/IL-3 was the most suitable for MPB to obtain high number of MK, and better than any other three groups (P < 0.05). The increase multiple of CD41+ cells was 93.97 +/- 17.27 on day 5 and 131.23 +/- 18.26 on day 10. On day 15, the proportion and the increase multiple of CD41+ cells decreased obviously. The expansion multiples of CFU-MK were 93.33 +/- 10.02 on day 5 and 120.67 +/- 13.01 on day 10, higher than any other groups. It is concluded that TPO/FL/IL-6/IL-3 combination was the best optimal for expansion ex vivo of megakaryocytic progenitors from MPB, and its suitable duration of culture was 10 days; a culture system for expansion ex vivo of megakaryocytic progenitors have been established in this study.