Comparative Studies of Platelet Survival by Different Methods in the Rabbit.

By SHIRLEY EBBE,#{176} MARIO BALDINI AND JANET DONOVAN T HE ABILITY of platelets to survive in the circulation appears to be their most labile property. Platelets may function normally in blood coagulation in the presence of damage severe enough to prevent their circulation when transfused to compatible recipients.1 After storage for 2 weeks, platelets still exhibit clot retraction,2 one of the most sensitive in vitro tests of platelet damage, but they would be destroyed immediately if transfused after this period of storage.3 Antiplatelet antibodies may destroy platelets when present in amounts too small to be detected by in vitro tests.4 Since transfused platelets must survive in the circulation to be effective hemostatically,5’6 measurement of their survival is the most direct method for studying their usefulness. The present studies were designed to evaluate several methods for measuring platelet survival in rabbits and the applicability of such measurements to human platelets. Platelet survival has been measured in rabbits with Cr#{176}L labeled plateletsT1#{176} and with P32-labeled platelets transfused as whole blood.1’ These studies have generally indicated a survival time of 3 or 4 days for rabbit platelets, with extremes of 2 and 6 days. Four methods for determining survival of homologous platelets were compared: ( 1 ) transfusion of nonlabeled platelets to thrombocytopenic recipients, ( 2 ) transfusion of concentrates of platelets labeled in vitro with Cr51-sodium chromate, (3) transfusion of concentrates of platelets labeled in vivo with P32-orthophosphate and (4) transfusion of whole blood labeled in vivo with P32-orthophosphate.