Platelet activation in coronary heart disease: assay, application and therapeutical perspectives

Platelet activation and/or platelet reactivity have been reported to be ass ociated with coronary heart disease. Whole blood how cytometry allows to an alyze platelets in their physiological environment, while other assays need platelet separation, susceptible to induce platelet modifications. But flo w cytometric assay also have limitations. We studied preanalytical conditions in healthy volunteers, using two monocl onal antibodies directed against CD62 and CD63 (two specific markers of pla telet degranulation), and two markers which recognize GPIIb/IIIa activation (PAC1 and bound fibrinogen). Preanalytical requirements were as follow: 1) whole blood samples need antagonists of platelet activation i.e., a mixtur e of theophylline, adenosine and dipyridamole, since artefactual platelet a ctivation rapidly occurred in citrated whole blood, 2) whole blood should b e immediately immunolabeled when samples arrived to laboratory, because fix ation did not prevent artefactual time dependent activation, 3) the stabili ty of immunolabeling was determinated for each monoclonal antibody: parafor maldehyde as fixative solution was mandatory For both CD62 and CD63, wherea s it enhanced bound fibrinogen and PAC1 expression, 4) platelets can be eas ily identified and gating on a dual scatter (forward scatter x side scatter ) dot plot with no specified labeling, The whole blood flow cytometric assay must be standardized in future clinic al studies, especially regarding to preanalytical requirements (J Mai Vasc 1999;24:288-293).