Abstract Number: VPB1140
Meeting: ISTH 2022 Congress
Background: Hemophilia A (HA) is an X linked bleeding disorder which is due to the deficiency of factor VIII (FVIII). Severity of the disease is categorized based on the FVIII level and the HA patients with factor level < 1% are characterized ad severe. Majority of these patients tend to have major hemorrhages. However, in general, 10% of severe patients compensate major bleeding. We hypothesize that activated platelets may have a role in compensation of bleeding severity in these patients.
Aims: To investigate the role of activated platelets in severe HA with mild hemorrhages.
Methods: Twelve severe HA patients and equal number of age matched normal were included after obtaining informed consent. Clinical details such as bleeding type, frequency and number of transfusions were recorded. 10 ml whole blood was collected and subjected for flow cytometry analyses to study the activated platelets. For this purpose, platelets were incubated with CD62P, PAC-1 and Annexin V and a minimum of 10,000 events were recorded for the analysis.
Results: All HA patients had < 1% FVIII and their age ranged between 7 and 39 years. Two of these patients never had muscle bleed and FVIII was infused to them only on demand. In addition to this, one of these two patients never developed any joint bleed. Based on bleeding and FVIII infusion, these patients were categorized as mild bleeders. When examined their platelets using flow cytometry, the PAC-1 binding were higher in both the patients (3.64% and 2.91% respectively) compared to that of normal (0.95%). However, the CD62P and AV binding in these patients were within the normal.
Conclusion(s): Patients with mild bleeding had higher expression of integrin receptor complex αIIbβ3 which indicates the activated status of platelets in them. Thus, it is possible that activated platelets may contribute to mild hemorrhage in these patients.
To cite this abstract in AMA style:Laha Roy C, Maharana S, Kishor K, Ranjan R, Mahapatra M, Saxena R, Kannan M. Role of activated platelets in compensation of bleeding severity in Hemophilia A [abstract]. https://abstracts.isth.org/abstract/role-of-activated-platelets-in-compensation-of-bleeding-severity-in-hemophilia-a/. Accessed February 28, 2024.
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