Effect of TPO on expansion of CD34+ cells from five patients. (a) Effect of TPO on expansion in SCF + Flt3-L alone and in SCF + Flt3-L + G-CSF. Bars represent mean and standard error. (b) Individual patient's responses in SCF + Flt3-L + G-CSF with or without TPO. These are different patients from those shown in figure 1.