Maintenance of surface antigens and the absence of an apoptotic marker are observed during storage of granulocyte concentrates collected by bag separation method

Granulocytes were collected by the bag separation method and stored in whole blood for up to 72 h. We evaluated the expressions of various surface antigens: CD62L, CD11b, CD18, CD64, CD16b, and CD95. Apoptosis was assessed both by flow cytometry and by light microscopy. Expression levels of all the surface antigens were shown to be maintained during storage for up to 72 h. Approximately 80% of granulocytes were annexin V negative until 72 h after collection. The storage of granulocyte concentrates collected by the bag separation method may maintain granulocyte surface antigens and lack an apoptotic marker.