rHuG-CSF increases the platelet-neutrophil complex formation and neutrophil adhesion molecule expression in volunteer granulocyte and stem cell apheresis donors.

Several reports have shown that granulocyte colony-stimulating factor (G-CSF) administration induces a transient, mild hypercoagulable state, which might predispose certain donors to thrombotic complications. In the present study, changes in the expression of neutrophil adhesion molecules (CD11b/CD18, CD62L) and platelet-neutrophil complex formation following rHuG-CSF administration were investigated in normal granulocyte and stem cell donors. For granulocyte apheresis (N = 10), rHuG-CSF (5 microg/kg) was given subcutaneously every 12 h three times and apheresis was carried out two hours after the last dose. For stem cell apheresis (N = 8), rHuG-CSF (10 microg/kg/day) was given subcutaneously for 5 days and apheresis was carried out when peripheral CD34+ cell counts exceeded 20 cell/microL. Expression of neutrophil adhesion molecules (CD11b/CD18, CD62L) and platelet-neutrophil complex formation following rHuG-CSF administration were investigated in donors by a flow cytometric method. A significant increase in neutrophil counts (P < 0.001), and decreases in platelet counts (P < 0.01) and hemoglobin levels (P < 0.01) occurred following G-CSF administration. The expression of CD11b/CD18 significantly increased (P < 0.001) over pretreatment values with G-CSF administration and returned to baseline 1 week after stopping the drug. In contrast, CD62L expression was decreased (P < 0.01) with G-CSF and returned to normal after cessation of the drug. rHuG-CSF caused more than a two-fold increase (from 0.3 to 7.0 x 10(9)/L) in circulating platelet-neutrophil complexes (P < 0.01), which returned to normal after 1 week. Although clinical significance of these laboratory changes is not clear, the occurrence of neutrophil activation and increased platelet-neutrophil complex formation might predispose certain donors or patients to thrombotic complications following G-CSF administration.