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

BACKGROUND: A study in humans showed that the transfusion of previously frozen human platelets after cardiopulmonary bypass, despite decreased survival, resulted in better hemostatic function than that of liquid‐preserved platelets stored at 22°C for 3 to 4 days. STUDY DESIGN AND METHODS: In this study, fresh, 3‐ to 4‐day‐old liquid‐preserved, and cryopreserved human platelets were studied by the use of monoclonal antibodies directed against p‐selectin, glycoprotein (GP)Ib, activated GPIIb/IIIa, and coagulation factor V in a three‐color flow cytometric method. RESULTS: The fresh and liquid‐preserved platelets had normal surface levels of GPIb, while the cryopreserved platelets were composed of distinct subpopulations of GPIb‐normal and GPIb‐reduced platelets. On the basis of the binding of factor V, both subpopulations of cryopreserved platelets exhibited greater surface binding of factor V than did fresh and liquid‐preserved platelets. Activated GPIIb/IIIa was elevated on GPIb‐normal platelets, but not on GPIb‐reduced platelets. Baboon platelets frozen by a procedure identical to that used to freeze human platelets also had GPIb‐normal and GPIb‐reduced 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 postinfusion 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 related to the rapid hemostatic effect of the GPIb‐reduced subpopulation secondary to increased binding of factor V and expression of p‐selectin.