Effects of ELT and iron-chelators on MK differentiation. MK differentiation was analyzed at day 7 of culture, under the same conditions as in Figure 1. (A) Results of a representative experiment showing the flow cytometric analysis of CD34 expression (y-axis, PE) and CD41 expression (x-axis, APC) in cells under the culture conditions shown. (B) Pie charts showing the distribution of cell populations based on CD34 and CD41 surface expression on day 7 of culture with TPO alone or TPO3 plus escalating concentrations of ELT, DFP, or DFO. Values shown represent the means of 6 independent experiments. Underlined values are significantly different from those obtained in cultures with TPO3 alone (P < .05). (C) Absolute cell numbers for each population under the different culture conditions were calculated based on cell counts and percentages obtained on day 7. Although all cell populations decreased in cultures containing high doses of ELT of iron chelators, the effects were more pronounced on cells expressing CD41, indicating MK commitment. Values shown in panels B and C represent the means ± SD of 6 independent experiments.