Platelet storage lesions: analysis of platelet membrane glycoproteins and platelet-derived microparticles by fluorescence-activated flow cytometry.
We have used recently developed flow cytometric techniques in combination with specific monoclonal antibodies (MoAbs): (i) to study the membrane expression of two major platelet glyco-protein (GP) complexes, GP Ib-IX and GP IIb-IIIa, and the appearance of activation-dependent membrane epitopes, and (ii) to evaluate the relative proportion of platelet-derived microparticles and their GP pattern during storage of platelet-rich plasma.  Binding of fluoresceinated (FITC) LJ-P3, an anti-GP Ibalpha MoAb, to platelets continuously decreased by 50% during storage for 6 days.  Binding of FITC-LJ-P4, directed to the GP IIb-IIIa complex on the platelet surface, also decreased during day 1-3, but increased again to baseline levels from day 4-6 of storage.  The re-increase of GP IIb-IIIa was associated with the exposure of secretion-dependent granule membrane proteins, GMP-140 and GP-53, and the presence of thrombospondin at the platelet surface.  These neoantigens are indicative of platelet activation. Moreover, the proportion of platelet-derived microparticles increased from 6 to 22% (p less than 0.001), whereby a predominant subpopulation of GP Ib-negative microparticles was identified.  Thus, significant changes in platelet membrane GP occur during standard platelet preservation.  These changes, resulting from time-dependent platelet activation and/or proteolysis in vitro may affect platelet GP receptor function upon transfusion.
Institute of Experimental Hematology and Transfusion Medicine, University of Bonn, Germany.
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Scharf
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Hanfland
D000911:Antibodies, Monoclonal; D001792:Blood Platelets; D001800:Blood Specimen Collection; D005434:Flow Cytometry; D006801:Humans; D015539:Platelet Activation; D010980:Platelet Membrane Glycoproteins / Q000032:analysis*; D011474:Prosthesis Design; D013997:Time Factors