1. Development of Lyophilized Human Platelets without HLA class I Antigens on Plasma Membrane(the 45th Annual Meeting)

Abstract

We have reported that the 1.8% paraformaldehyde-fixed and lyophilized human platelets retained surface Glycoprotein I b with function, and that may be one of the candidates as platelet substitutes. In this paper, we focused on HLA class I antigens on plasma membrane which are recognized by anti-HLA class I alloantibodies in alloimmunized patients. To eliminate HLA class I antigens, we treated fresh human platelets with acid buffer at pH3.0 and subsequently fixed with 1.8% paraformaldehyde. Aggregation analysis and flowcytometric analysis demonstrated that acid treated, lyophilized and rehydrated plateletes possessed ristocetin-dependent aggregation and HLA class I antigens on platelet surface were completely eliminated. These platelets may not be recognized by anti-HLA class I antibodies, and it is expected that these platelets would be applied to the patients refractory to platelet transfusions. These results suggest that acid-treated and lyophilized platelets may be useful as a platelet substitute.