PLATELET-DERIVED MICROPARTICLES IN PATIENTS WITH SEVERE HEMOPHILIA

WILLIAMS G MARCELA; MARONI G; OJEDA M ; ENSINCK M. A; CASTRO J; DAVOLI M; PRATTI A; DETARSIO G; RAVIOLA M

Rosario

Congreso; XLI ANNUAL MEETING -ROSARIO SOCIETY OF BIOLOGY; 2021

SOCIEDAD DE BIOLOGÍA DE ROSARIO

Platelet microparticles (PM) are small phosphatidyl serine rich platelet-derived vesicles (100 nm–1 µm), involved inthe maintenance of hemostasis. It was proposed that, in hemophiliac patients, they could improve the bleeding profileafter factor replacement therapy. The aim of this study was determined if the percentage (%) of plasma MPs inpatients with severe hemophilia A before and after factor VIII infusion is different from the % found in normalcontrols. We studied platelet-free citrated plasma samples obtained from 20 normal individuals and 19 patients withsevere hemophilia A pre-infusion, 30 min after factor VIII infusion. MPs were quantified by flow cytometry using aCD 41 (P2) IOT PE monoclonal antibody. The samples were studied with a BD model FACSAria II cytometer anddata were analyzed with the FACSDiva v.6.1.3 software. The medians of MPs % were: Pre-treatment patients, 0.50%;post-infusion, 0.46%; normal controls, 0.04%. Data analysis showed a difference between the % of MPs found inhemophiliacs compared to controls, but we did not observe a difference between pre- and post-treatment samples.Unlike other studies, our results show a higher % of MPs in hemophiliacs compared to controls; this could explaintheir role in a compensatory mechanism of thrombin activation in hemophilia. However, replacement therapy doesnot modify MPs %, therefore in this condition MPs could not be involved in ameliorating the hemorrhagic phenotypeof the patients.