CHANGES IN BLOOD COUNTS AFTER THE ADMINISTRATION OF GRANULOCYTE-COLONY-STIMULATING FACTOR AND THE COLLECTION OF PERIPHERAL-BLOOD STEM-CELLSFROM HEALTHY DONORS

Background: After the collection of granulocyte-colony-stimulating fac tor (G-CSF)-mobilized peripheral blood stem cells from healthy donors, the donor platelet counts fall. However, the magnitude and duration o f this decrease are not known. Study Design and Methods: Sixty healthy people were given G-CSF (5, 7.5, or 10 mu g/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, he matocrit, 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 10(9) cells per L on Day 0 to 159 +/- 30 x 10(9) cel ls per L on Day 8 (p<0.0001) and reached its lowest level on Day 10 (1 46 +/- 30 x 10(9)/L; p<0.001). Compared to Day 0 levels, the platelet count was lower on Day 13 (185 +/- 49 x 10(9)/L, p<0.001), was the sam e on Day 16 (270 +/- 53 x 10(9)/L), and was greater on Day 20 (333 +/- 60 x 10(9)/L, p<0.0001). The white cell count returned to pretreatmen t values on Day 13, and the absolute neutrophil count returned to pret reatment values on Day 10 (Day 0 white cell count = 6.05 +/- 1.59 x 10 (9)/L and Day 0 absolute neutrophil count = 3.97 +/- 1.52 x 10(9)/L). On Day 20, both were less than pretreatment values (white cell count = 5.14 +/- 1.24 x 10(9)/L, p = 0.0007 and absolute neutrophil count = 3 .20 +/- 1.24 x 10(9)/L, p = 0.0036). The red cell counts on Day 16 (4. 52 +/- 0.41 x 10(12)/L) and Day 20 (4.42 +/- 0.39 x 10(12)/L) were les s than Day 0 values (4.73 +/- 0.43 x 10(12)/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 bl ood counts were not affected by the dose of the G-CSF. Conclusion: Aft er stimulation with granulocyte-colony-stimulating factor and the coll ection of peripheral blood stem cells, the platelet counts in normal d onors were decreased for at least 7 days (Days 6-13). Two weeks after collection of peripheral blood stem cells (Day 20), platelet productio n was increased, but the production of neutrophils and red cells was d ecreased. If two or more peripheral blood stem cell components are col lected, then the platelet count should be measured after the second an d subsequent collections. Further studies on the long-term effect of G -CSF on blood counts are needed.