ACID TREATMENT OF PLATELETS AS A SIMPLE PROCEDURE FOR DISTINGUISHING PLATELET-SPECIFIC ANTIBODIES FROM ANTI-HLA ANTIBODIES - COMPARISON WITH CHLOROQUINE TREATMENT

Abstract. The identification of antibodies to platelet‐specific antigens is important for correctly diagnosing neonatal alloimmune thrombocytopenia, posttransfusion purpura and refractoriness due to platelet‐specific antibodies. However, the serologic identification of these platelet‐specific antibodies is complicated by the presence of anti‐HLA antibodies. We examined and compared the diagnostic usefulness of acid‐treated and chloroquine‐treated platelets for the discrimination of platelet‐specific antibodies from anti‐HLA antibodies. The viability of acid‐treated platelets is 83.4%, which is better than that of chloroquine‐treated platelets (52.6%). The antigenicity of HLA class I antigens of acid‐treated platelets was significantly reduced compared with that of PBS‐ or chloroquine‐treated platelets. On the other hand, platelet surface glycoprotein Ib and glycoprotein IIb/IIIa, and platelet‐specific antigens were stable following acid or chloroquine treatment. Chloroquine‐treated platelets were not suitable targets for analysis by immunofluorescence flow cytometry because of nonspecific fluorescence derived from platelet damage. We conclude that acid‐treated platelets are more suitable targets than chloroquine‐treated platelets for screening for platelet‐specific antibodies and also for analyses of the specificity of platelet‐specific antibodies. © 1990 S. Karger AG, Basel