Abstract Number: PB1427
Meeting: ISTH 2020 Congress
Background: Heparin-induced thrombocytopenia (HIT) is a rare medical complication of heparin therapy, when antibodies are formed against the complex “heparin-PF4”. They activate and destroy platelets, damage endothelium, increase thrombin generation. Most often this reaction appears on the 5-14th day of heparin therapy, the platelet count decreases more than 50% and new thrombosis are diagnosed. Diagnosis of this pathology is difficult, the main symptoms are nonspecific, especially for patients in critical injuries with initial thrombocytopenia. Use of SRA for diagnostics is limited, but using flow cytometry has opened up a new possibilities.
Aims: Study the functional activity of platelets of patient with confirmed HIT by flow cytometry with and without preliminary heparin-incubation
Methods: The diagnosis of HIT was confirmed on the test-system “HIT-Ab” (IL), the concentration of antibodies – 6.4 U/ml (threshold value < 1.0). The study by flow cytometry was carried out on FACS Canto II (BD Biosciences). The platelet population has been identified by expression of CD61 and CD42b, which were selected as a main platelets markers. In this population we investigated CD62p (a marker of alpha-granules) and Annexin V (a marker of procoagulant activity).The results were compared with donor data.
Results: Comparing the response of platelets to heparin influence was found, that the number of CD62p-positive platelets increased from 26.1% to 47.2% after incubation. The MFI of this population increased from 131 to 761. Most of the patient´s platelet initially expressed CD62p, which could be due to their pre-activation or transportation. When the donor´s platelet was studied under the same conditions, the number of CD62p-positive platelets decreased after incubation from 6.3 to 3.8%. Reliable changes in procoagulant activity was not obtained.
Conclusions: Platelet flow cytometry may be an alternative and more convenient functional test for the advanced diagnosis of heparin-induced thrombocytopenia. The possibility of its use requires in further study.
To cite this abstract in AMA style:Lavrova P, Orel E, Zakharko E, Drokova D, Rybkina E, Matokhina K, Dvirnyk V. Platelet Flow Cytometry in the Diagnosis of Heparin-induced Thrombocytopenia [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/platelet-flow-cytometry-in-the-diagnosis-of-heparin-induced-thrombocytopenia/. Accessed January 28, 2022.
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