Role of platelets in the pathogenesis of antiphospholipid syndrome

Abstract

Aim: To delineate the role of platelets in thrombotic process in APS patients. Background: Pathogenesis of APS is an ongoing area of research and studying the role of platelets will be helpful in developing newer diagnostic and therapeutic strategies. Materials and methods: Forty patients with APS, diagnosed as per modified 2006 Sapporo’s Criteria and who were not on aspirin or any other antiplatelet drug, were included. The same number of age- and sex-matched healthy controls was also recruited for comparison. The following platelet function studies were performed using the blood samples collected from APS patients as well as healthy controls: platelet aggregation studies, platelet secretion of dense granules (a. total degranulation b. platelet secretion of granules in relation to time c. visualization of platelet degranulation), clot retraction studies, and western blot studies on clot retracted samples for demonstration of activated proteomes. Results: A significant increase (P < 0.001) in the platelet aggregation in APS patients as compared to healthy controls was noted. The subjects also showed a significant increase (P < 0.05) in the platelet granule release as well as more degranulation (P < 0.001) in relation to time at stored condition, which were well-visualized under phase-contrast microscope. Sixty-five percent of APS patients showed lesser as well as delayed clot retraction as compared to healthy controls, signifying that the platelet clots are less retractile in APS patients. Conclusion: The study clearly demonstrates the hyperactivity of platelets in APS patients in each step of their activation as compared to the controls. This indicates the major role played by platelets in APS pathogenesis.