HLA–C Antigens on Platelets1

Abstract
The direct demonstration of HLA–C antigens Cw2, Cw3, and Cw4 on human platelets is described. The antigens were detected by means of a platelet radioimmune anti‐IgG test using acid eluates from platelets and lymphocytotoxic antisera. It is concluded that HLA–C determinants are only weakly expressed on platelets. Individual differences observed reflect antigenic variations.