COMPARATIVE-STUDY OF 3 METHODS TO DETECT FREE PLASMA ANTIPLATELET ANTIBODIES

We have compared three techniques for the detection of plasma circulat ing antiplatelet antibodies, i.e., the platelet suspension immunofluor escence test (PSIFT), the platelet radioactive antiglobulin test (PRAT ), and the monoclonal antibody immobilization of platelet antigens (MA IPA). Frozen plasma samples from patients with idiopathic thrombocytop enic purpura or HIV-associated thrombocytopenia were used in the study . The PSIFT and PRAT showed the appropriate ease of performance necess ary for screening purposes. The PSIFT is free of radioactivity hazards , but seemed to be less sensitive than the PRAT. The MAIPA is a useful tool to detect antibodies against glycoproteins (GPs) Ib/IX and IIb/I IIa. However, in comparison to PSIFT and PRAT, MAIPA is more time cons uming, requires considerable technical expertise, and the identificati on of antiplatelet activity is highly dependent on the selection of an appropriate primary anti-GP monoclonal antibody. This could explain t he lower prevalence of antiplatelet activity detected by MAIPA, in com parison to the frequency provided by the PSIFT and PRAT.