Serum levels of SCF. Blood was taken before administration of each dose of SCF. Results are mean ± SE for SCF 5 μg/kg/d plus G-CSF (Cohort B, n = 5, ▿), SCF 10 μg/kg/d plus G-CSF (Cohort C, n = 11, •), SCF 15 μg/kg/d plus G-CSF (Cohort D, n = 10, □), and SCF pretreatment (Cohort E, 10 μg/kg, n = 18, ▴). Time is shown relative to administration of G-CSF. Serum concentration is corrected for baseline values.