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.

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We investigated whether circulating leucocytes from hypertensive patients exhibit more spontaneous, stimulated hydrogen peroxide (H 2 O 2 ) production and greater mitochondrial membrane potential (Dw) than those from normotensive individuals. We also investigated the effects of oral treatment with the angiotensin II (AT II) type 1 receptor blocker eprosartan (600 mg day À1) on these markers of oxidative stress. In 25 hypertensive patients and 28 healthy volunteers, spontaneous H 2 O 2 formation was measured by flow cytometry after preincubation of buffy coat-leucocytes from fresh peripheral venous blood at 37 1C with 2 0 ,7 0 dichlorofluorescein. Stimulation of H 2 O 2 formation by circulating leucocytes was elicited by the addition of tert-butylhydroperoxide (tBHP). Dw was determined by flow cytometry after the addition of tetramethylrhodamine methyl ester (TMRM). Compared with healthy individuals, lymphocytes from hypertensive patients exhibited higher Dw (12.28±3.20 vs 16.25±2.88 arbitrary fluorescence units (AFU), respectively; Po0.001) and greater spontaneous H 2 O 2 production (4.75 ± 5.15 vs 8.98 ± 9.97 AFU, respectively; Po0.05). tBHP stimulation was associated with higher H 2 O 2 levels in circulating leucocytes in patients with uncorrected hypertension than in normotensive individuals. H 2 O 2 overproduction was corrected by eprosartan treatment. These results suggest that oxidative stress could be important in the pathogenesis of hypertension. Furthermore, measurement of leucocyte oxidant activities may be useful for the evaluation of oxidative stress, which may be reduced with the use of antihypertensive drugs. Our results demonstrate that treatment of hypertension with eprosartan normalizes blood pressure and corrects oxidative disturbances, suggesting that leucocytes could be a target for this drug.