A standard microlymphocytotoxicity assay was used to test the sera for HLAantibodies in the patients receiving multitransfusions and to identify their speci-ficity,and at the same time the platelet-associated antibodies were detected.As a result,the dectable rate of HLA antibodies was 39.14% (119/304),of which24.37% (29/119) had specificity;the positive rat platelet-associated antibodieswas 39.83% (47/118).The frequency of positive incidence of HLA antibodiesincreased with the number of transfusions and donors,having a significant differ-ence.The nonhemolytic reaction to transfusion was associated with HLA antibodi-es.The frequency of positive incidence of HLA antibodies was the highest whenthe patients were transfused with concentrated granulocytes.There were takensome measures to prevent and reduce the transfusion reaction.