Increased activated platelet binding to T cells in lung cancer patients is correlated with history of thrombosis

Abstract

This study aimed to characterize the role of platelet-leukocyte aggregation in lung cancer patients in context of history of thrombosis. Whole blood from lung cancer patients and healthy volunteers was labeled with fluorescently-conjugated antibodies, then fixed prior to flow cytometry. Platelet-leukocyte aggregates were quantified by detecting the number of platelets within all leukocyte-positive events. Platelet-CD4 T cell and platelet-CD8 T cell aggregates were both significantly increased in lung cancer patients (both p < 0.0001). Lung cancer patients had significantly more CD4 and CD8 T cells aggregated with activated platelets compared to healthy volunteers (p < 0.01 and p < 0.001, respectively). Lung cancer patients were then separated into groups based on history of thrombosis: No previous thrombosis, arterial thrombotic event (ATE), and venous thromboembolism (VTE). ATE patients had significantly more CD8 T cells aggregated with platelets than patients with no history of thrombosis (p < 0.05). VTE patients had significantly higher expression of platelet activation markers in CD4 and CD8 T cell aggregates than patients with no history of thrombosis (p < 0.01 and p < 0.001, respectively) and ATE patients (p < 0.05 and p < 0.001, respectively). Platelet-T cell aggregates were significantly increased in lung cancer patients compared to healthy volunteers, and platelet activation within aggregates was significantly correlated with history of VTE in patients with lung cancer. These findings indicate that interactions between platelets and T cells in cancer patients may contribute to a procoagulant phenotype.