Fresh, liquid-preserved, and cryopreserved platelets: adhesive surface receptors and membrane procoagulant activity

BACKGROUND: A study in humans showed that the transfusion of previously fro zen human platelets after cardiopulmonary bypass, despite decreased surviva l, resulted in better hemostatic function than that of liquid-preserved pla telets stored at 22 degrees C for 3 to 4 days. STUDY DESIGN AND METHODS: In this study, fresh, 3- to 4-day-old liquid-pres erved, and cryopreserved human platelets were studied by the use of monoclo nal antibodies directed against p-selectin, glycoprotein (GP)Ib, activated GPIIb/IIIa, and coagulation factor V in a three-color flow cytometric metho d. RESULTS: The fresh and liquid-preserved platelets had normal surface levels of GPIb while the cryopreserved platelets were composed of distinct subpop ulations of GPIb-normal and GPIb-reduced platelets. On the basis of the bin ding of factor V, both subpopulations of cryopreserved platelets exhibited greater surface binding of factor V than did fresh and liquid-preserved pla telets. Activated GPIIb/IIIa was elevated on GPIb-normal platelets, but not on GPIb-reduced platelets. Baboon platelets frozen by a procedure identica l to that used to freeze human platelets also had GPIb-normal and GPIb-redu ced subpopulations after the freezing-thawing-washing procedure. Autologous cryopreserved baboon platelets labeled with biotin-X-N-hydroxysuccinimide showed a rapid removal of GPIb-reduced platelets during the 5-minute postin fusion period, whereas GPIb-normal platelets had an in vivo recovery of 48 percent and a lifespan of slightly less than 6 days. CONCLUSIONS: Improved in vivo function of cryopreserved platelets may be re lated to the rapid hemostatic effect of the GPIb-reduced subpopulation seco ndary to increased binding of factor V and expression of p-selectin.