Changes in blood counts after the administration of granulocyte-colony- stimulating factor and the collection of peripheral blood stem cells from healthy donors

Background: After the collection of granulocyte-colony-stimulating factor (G-CSF)mobilized peripheral blood stern cells from healthy donors, the donor platelet counts fall. However, the magnitude and duration of this decrease are not known. Study Design and Methods: Sixty healthy people were given G-CSF (5, 7.5, or 10 μg/kg/day) for 5 days (Days 1-5), and 1 peripheral blood stem cell component was collected on Day 6. The platelet count, white cell count, absolute neutrophil count, hematocrit, and red cell count were measured before administration of G-CSF (Day 0), before collection of peripheral blood stem cells on Day 6, and on Days 8, 10, 13, 16, and 20. Results: The platelet count fell from 261 ± 47 x 10⁹ cells per L on Day 0 to 159 ± 30 x 10⁹ cells per L on Day 8 (p<0.0001) and reached its lowest level on Day 10 (146 ± 30 x 10⁹/L; p<0.001). Compared to Day 0 levels, the platelet count was lower on Day 13 (185 ± 49 x 10⁹/L, p<0.001), was the same on Day 16 (270 ± 53 x 10⁹/L), and was greater on Day 20 (333 ± 60 x 10⁹/L, p<00001). The white cell count returned to pretreatment values on Day 13, and the absolute neutrophil count returned to pretreatment values on Day 10 (Day 0 white cell count = 6.05 ± 1.59 x 10⁹/L and Day 0 absolute neutrophil count = 3.97 ± 1.52 x 10⁹/L). On Day 20, both were less than pretreatment values (white cell count = 5.14 ± 1.24 x 10⁹/L, p = 0.0007 and absolute neutrophil count = 3.20 ± 1.24 x 10⁹/L, p = 0.0036). The red cell counts on Day 16 (4.52 ± 0.41 x 10¹²/L) and Day 20 (4.42 ± 0.39 x 10¹²/L) were less than Day 0 values (4.73 ± 0.43 x 10¹²/L, p = 0.008 and p<0.0001, respectively). The hematocrit on Day 20 (39.2 ± 3.2%) was also less than that on Day 0 (41.2 ± 4.8%; p = 0.01). The changes in these blood counts were not affected by the dose of the G-CSF. Conclusion: After stimulation with granulocyte-colony-stimulating factor and the collection of peripheral blood stem cells, the platelet counts in normal donors were decreased for at least 7 days (Days 6-13). Two weeks after collection of peripheral blood stern cells (Day 20), platelet production was increased, but the production of neutrophils and red cells was decreased. If two or more peripheral blood stem cell components are collected, then the platelet count should be measured after the second and subsequent collections. Further studies on the long-term effect of G-CSF on blood counts are needed.