Blood counts in healthy donors 1 year after the collection of granulocyte-colony-stimulating factor-mobilized progenitor cells and the results of a second mobilization and collection

BACKGROUND : Granulocyte–colony-stimulating factor (G–CSF)-mobilized blood cells are being used for allogeneic transplants, but the long-term effects of G–CSF on healthy individuals are not known. Furthermore, it is not certain how many CD34+ cells can be collected in a second mobilization and collection procedure. STUDY DESIGN AND METHODS : Nineteen people were given 2, 5, 7.5, or 10 μg of G–CSF per kg per day for 5 days, and blood progenitor cells were collected by apheresis on the sixth day; this was done on two occasions separated by at least 12 months. Blood counts obtained before and after each course of G–CSF and the quantity of cells collected were compared. RESULTS : There were no differences in white cell (WBC), platelet, red cell, and WBC differential counts measured before each course of G–CSF, and all the values were in the normal range. In a subset of 12 people who received 7.5 or 10 μg of G–CSF per kg per day for both courses, the numbers of neutrophils, mononuclear cells, and CD34+ cells in the blood after each course were similar (34.1 ± 7.31 × 10⁹/L vs. 36.4 ± 12.3 × 10⁹/L, p = 0.24; 6.59 ± 2.28 × 10⁹/L vs. 5.63 ± 2.11 × 10⁹/L, p = 0.24; and 92.0 ± 55.6 × 10⁶/L vs. 119.2 ± 104.6 × 10⁸/L; p = 0.48, respectively), as were the quantities of mononuclear cells (31.0 ± 8.4 × 10⁹ vs. 31.0 ± 6.1 × 10⁹; p = 0.64) and CD34+ cells (417 ± 353 × 10⁶ vs. 449 ± 286 × 10⁶; p = 0.53) collected in the two apheresis procedures. Furthermore, there was a positive correlation between the quantity of CD34+ cells collected from each of the 12 people per liter of whole blood processed in the two procedures (r² = 0.86, p<0.001). CONCLUSION : One year after the administration of G–CSF to healthy people, their blood counts were normal and unchanged from pretreatment counts. If healthy people donate blood progenitor cells after a second G–CSF course, the quantity of CD34+ cells collected will be similar to that obtained in the first collection.