Recombinant human granulocyte colony-stimulating factor (rhG-CSF) promotes in vitro platelet aggregation

rhG-CSF is increasingly used for stimulation of granulopoiesis and stem cell mobilization in healthy donors for allogeneic stem cell transplantation. However, a possible association between thrombosis and rhG-CSF administration has been reported. For that reason, in this study, we investigated the effect of rhG-CSF on platelet aggregation in whole blood of 10 healthy volunteers. Three concentrations of rhG-CSF solution (1, 10 and 100 ng/ml) were prepared. Each concentration of rhG-CSF solution and a control diluent without rhG-CSF were incubated with whole blood. Incubation with rhG-CSF solutions would result in 0.1, 1.0 and 10 ng/ml rhG-CSF concentrations in the blood. After incubation, aggregation responses were evaluated with ADP (5 and 10 microM) and collagen (2 and 5 microg/ml) in whole blood. When compared to control, preincubation with all dilutions of rhG-CSF augmented aggregation of platelets induced by ADP and collagen in a statistically significant manner (p < 0.05 for all comparisons). There was also a relationship between rhG-CSF concentration (1, 10 and 100 ng/ml) and augmentation of platelet aggregation response (p < 0.0001 for 5-10 microM ADP; p < 0.0001 for 2-5 microg/ml collagen). In conclusion, this study with an in vitro model showed that rhG-CSF administration may lead to platelet hyperaggregability.