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 micrograms 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 micrograms 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(5)/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 (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.