A clinical program of platelet cryopreservation

A program of platelet cryopreservation has been developed at the Baltimore Cancer Research Center which now provides substantial proportion of the platelet transfusion requirements of alloimmunized patients. The program has gradually grown in size during the last eight years and in 1979 approximately 1600 units of frozen platelets were transfused including 225 transfusions of autologous platelets administered to 45 patients with leukemia. For many alloimmunized patients autologous frozen platelets represented the only source of histocompatible platelets. 5% dimethylsulfoxide is used as the cryoprotective agent and the platelets can be maintained in the frozen state for at least three years without significant reduction in effectiveness. There are essentially no side effects following transfusion and patient acceptance has been excellent. Post-transfusion increments have been highly consistent during the last five years, averaging two thirds of the recovery obtained with fresh platelets with accompanying shortening of the bleeding time. The technology is simple, cost effective and reproducible and is suitable for use in more general blood bank settings.