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 mg/kg intravenous dose of G-CSF with or without dexamethasone. Sixteen subjects will be studied. Each donor is being studied four separate times. The four mobilization protocols are G-CSF 5 mg/kg given intravenously, G-CSF 5 mg/kg subcutaneously, G-CSF 5 mg/kg intravenously plus dexamethasone 8 mg orally, and G-CSF 5 mg/kg subcutaneously plus dexamethasone 8 mg orally. The order of the route of administration is being assigned randomly. White blood cell counts, neutrophil counts and donor symptoms are being 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 are being compared with counts measured 24 hours after G-CSF. This study has just begun; four subjects have been studied. Preliminary results suggest that the granulocyte counts at 6 and 8 hours after the administration of the agents are similar to the counts after 24 hours, granulocyte mobilization with intravenous and subcutaneous G-CSF is similar, granulocyte mobilization with G-CSF plus dexamethasone is better that mobilization with G-CSF alone.
