EFFECT OF COLD-STORAGE ON PLATELET GLYCOPROTEIN IB AND VESICULATION

Background: During storage of platelet concentrates at 22 degrees C, changes occur in surface glycoproteins, and membranous vesicles appear in the supernatant plasma. The extent of these changes during refrigerated storage is not known. Study Design and Methods: Membranous microparticles and changes in surface or total glycoprotein Ib (GPIb) were studied in platelet concentrates divided into aliquots stored at either 4 degrees C or 22 degrees C for 5 days. Results: The refrigerated platelets showed greater loss of total GPIb slightly less binding of monoclonal antibodies to surface GPIb, and reduced aggregation response to ristocetin relative to the paired platelet controls at 22 degrees C. Moreover, the platelets stored at 4 degrees C produced 45-percent more microparticles and 64-percent more platelet factor 3 activity in the supernatant plasma than were produced by the controls. These differences were augmented by warming both 4 degrees C- and 22 degrees C-stored platelets at 37 degrees C for 1 to 4 hours. Conclusion: Storage of platelets at 4 degrees C causes increased membrane vesiculation and accelerated loss of GPIb. The magnitude of these differences was small, but it may contribute to marked reductions in platelet survival in circulation.