PLATELET-RELEASE REACTION DURING EDTA-INDUCED PLATELET AGGLUTINATIONSAND INHIBITION OF EDTA-INDUCED PLATELET AGGLUTINATION BY ANTI-GLYCOPROTEIN IIB IIIA COMPLEX MONOCLONAL-ANTIBODY/

To characterize the nature of EDTA-induced platelet agglutination, the spontaneous release of beta-thromboglobulin (beta-TG) and platelet fa ctor 4 (PF4) was examined during EDTA-induced platelet agglutinations. A slight release of beta-TG and PF4 was observed when EDTA-anticoagul ated whole blood from cases with EDTA-induced platelet agglutination w as kept for 60 minutes, whereas a high spontaneous release of these pr oteins was found from normal blood anticoagulated with EDTA. These fin dings imply that EDTA-dependent platelet agglutinin may stabilize the platelet membrane surfaces. Secondly, we found that pretreatment of fr esh blood with anti-glycoprotein (GP) IIb/IIIa complex monoclonal anti body dramatically reduced EDTA-induced platelet agglutinations. This s tudy indicated that the binding sites of EDTA-dependent antibody might be GP IIb/IIIa complex. The use of an anti-GP IIb/IIIa complex monocl onal antibody may be useful in avoiding analytical errors in some case s with EDTA-induced pseudothrombocytopenia.