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 x 10 9 /L vs. 36.4 ± 12.3 x 10 9 /L, p = 0.24; 6.59 ± 2.28 x 10 9 /L vs. 5.63 ± 2.11 x 10 9 /L, p = 0.24; and 92.0 ± 55.6 x 10 6 /L vs. 119.2 ± 104.6 x 10 6 /L; p = 0.48, respectively), as were the quantities of mononuclear cells (31.0 ± 8.4 x 10 9 vs. 31.0 ± 6.1 x 10 9 ; p = 0.64) and CD34+ cells (417 ± 353 x 10 6 vs. 449 ± 286 x 10 6 ; 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 (r 2 = 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.