Platelet activation and red blood cell phosphatidylserine exposure evaluated by flow cytometry in patients with Behçet's disease: are they related to thrombotic events?

Behçet's disease (BD) is associated with an increased risk of venous and arterial thromboses that are associated with morbidity and mortality increase, although the mechanisms are not well established. In the present study, we used whole blood cytometry to determine the exposure of CD62 on the surface of platelets and the expression of phosphatidylserine (PS) on the surface of circulating red blood cells. Microparticle and microaggregate formation from platelets were also determined in a well-classified group of 72 patients (39 males, 33 females, aged 46.5 +/- 12.5 years) with BD, in comparison with a well-matched control group of 72 healthy volunteers. Results showed no differences in the above-mentioned parameters when BD patients and controls were compared. However, when we compared BD patients with/without thrombosis using these parameters, there were significant differences between both groups. BD patients with previous thrombosis had a higher percentage of circulating CD62-positive platelets and a higher number of circulating microaggregates than those without thrombosis, suggesting that platelet activation may be involved in the development of thrombotic events in these patients.