Effect of elastase on CD34⁺ growth.

CD34⁺ cells (10⁵/mL) were cultured in the presence of 10 ng/mL G-CSF, GM-CSF, and SCF with different concentrations of elastase. (A) After 10 days of culture, nucleated cells were counted. Asterisks indicate significant differences from control values (*P < .005; **P < .01). Data are representative of 3 independent experiments. (B) Daily measurement of proliferation by tritiated thymidine uptake. Data are presented as mean (± SEM) of the triplicates. CPM indicates counts per minute; ●, control; and ○, elastase.