Allogeneic-blood stem-cell collection following mobilization with low- dose granulocyte colony-stimulating factor

Purpose: The optimal dose of granulocyte colony-stimulating factor (G- CSF) for mobilizatlon of allogeneic-blood stem cells (AlloBSC) has yet to be determined. As part of a prospective trial, 41 related human leukocyte antigen (HLA)-matched donors had blood cells mobilized with G-CSF at 5 μg/kg/d by subcutaneous administration. The purpose of this trial was to monitor adverse effects during G-CSF administration and stem-cell collection, to determine the optimal timing for stem-cell collection, and to determine the cellular composition of stem-cell products following G-CSF administration. Patients and Methods: The median donor age was 42 years. Apheresis began an day 4 of G-CSF administration. At least three daily 12-L apheresis collections were performed on each donor. A minimum of 1.0 x 10⁶ CD34⁺ cells/kg (recipient weight) and 8.0 x 10⁸ mononuclear cells/kg were collected from each donor. All collections were cryopreserved in 5% dimethyl sulfoxide and 6% hydroxyethyl starch. Results: Toxicities associated with G- CSF administration and the apheresis process included myalgias/arthralgias (83%), headache (44%), fever (27%), and chills (22%). The median baseline platelet count of 242 x 10⁶/mL decreased to 221, 155, and 119 x 10⁶/mL on days 4, 5, and 6 of G-CSF administration, respectively. Median numbers of CD34⁺ cells in collections 1, 2, and 3 were 1.99, 2.52, and 3.13 x 10⁶/kg, respectively. The percentage and total number of CD4⁺, CD8⁺, and CD56⁺/CD3^- cells remained relatively/constant during the three collections. Median total numbers of cells were as follows: CD34⁺, 7.73 x 10⁶/kg; and lymphocytes, 6.93 x 10⁸/kg. Conclusion: Relatively low doses of G-CSF can mobilize sufficient numbers of AlloBSC safely and efficiently.