The administration of granulocyte colony-stimulating factor (G-CSF) to increase the white blood cell count in granulocyte donors prior to donation is becoming an increasingly common practice. G-CSF is given subcutaneously to the donor on the day prior to donation, generally 12 to 24 hours before the start of apheresis. It would be advantageous to be able to give G-CSF and collect granulocytes on the same day. However, the single most important factor in optimizing granulocyte collection is the donor's pre-collection granulocyte count. Therefore, any decrease in count would result in a less cellular component. The purpose of this study is to assess granulocyte counts in healthy subjects during an 8-hour period after a single 5 microgram/kg intravenous dose of G-CSF with or without dexamethasone. Sixteen subjects will be studied. Each donor will be studied four separate times. The four mobilization protocols to be studied are G-CSF 5 micrograms/kg given intravenously, G-CSF 5 micrograms/kg subcutaneously, G-CSF 5 micrograms/kg intravenously plus dexamethasone 8 mg orally, and G-CSF 5 micrograms/kg subcutaneously plus dexamethasone 8 mg orally. The order of the route of administration will be assigned randomly. White blood cell counts, neutrophil counts and donor symptoms will be measured before G-CSF administration and at 1/2, 1, 2, 4, 6, 8 and 24 hours after administration. The neutrophil counts measured within the first 8 hours after G-CSF will be compared with counts measured 24 hours after G-CSF.