Effective storage of granulocytes collected by centrifugation leukapheresis from donors stimulated with granulocyte-colony-stimulating factor.

Background: Donor stimulation with granulocyte-colony-stimulating factor (G-CSF) has increased the number of neutrophils (PMNs) that can be collected for granulocyte transfusion therapy. Clinical utility, however, has been limited by the inability to store functional PMNs ex vivo. This study was conducted to determine whether granulocyte products from G-CSF-stimulated donors could be effectively stored at reduced temperature (22 degrees C vs. 10 degrees C) with maintenance of functional properties in vitro and in vivo.

Study Design And Methods: Nine normal subjects received G-CSF (600 microg subcutaneously) 12 hours before centrifugation leukapheresis. Granulocyte products were divided and stored for 24 and 48 hours under four conditions: 1) 22 degrees C; 2) 22 degrees C, with supplemental G-CSF (100 ng/mL); 3) 10 degrees C; and 4) 10 degrees C, with supplemental G-CSF. Functional PMN activity during ex vivo storage was assessed in vitro and in vivo by the skin-window technique for granulocytes stored at 10 degrees C for 24 hours.

Results: Surface expression of CD11b/CD18, CD14, CD16, CD32, and CD64 was maintained during 48-hour storage at reduced temperature. Inducible respiratory burst activity, bactericidal activity, and fungicidal activity were preserved during storage for 48-hour storage at 10 degrees C. Proinflammatory cytokine production was decreased in product stored at 10 degrees C. Supplemental G-CSF ex vivo did not substantially improve functional activity during storage. After storage at 10 degrees C for 24 hours, in vitro chemotactic potential was maintained, and transfused granulocytes retained capacity to circulate and migrate appropriately in vivo.

Conclusions: Granulocyte product collected by centrifugation leukapheresis from G-CSF-stimulated donors can be effectively stored at subphysiologic temperature for 24 hours with preservation of functional activity. Storage at 10 degrees C appears to be slightly superior to storage at 22 degrees C.