Behcet's syndrome (BS) is a relapsing, chronic, inflammatory disease characterized by endothelial dysfunction, atherothromboembogenesis, and leukocytoclastic vasculitis with complex immunologic molecular interactions. Generalized derangements of the lymphocyte and neutrophil Populations, activated monocytes, and increased PMNLs motility with upregulated cell surface Molecules such as ICAM-1, VCAM-1, and E-selectin, which are found on the endothelial cells, leukocytes, and platelets, have all been demonstrated during the Course of BS. Our aim is to investigate the association of serum concentrations of soluble P-selectin in patients with BS, and to evaluate whether disease activity has an effect on their blood levels. This multicenter study included 31 patients with BS (15 men and 16 women) and 20 age- and sex-matched health), control volunteers (11 men and nine women). Neutrophil count, erythrocyte sedimentation rate, and acute-phase reactants as well as soluble P-selectin levels were determined. The mean age and sex distributions were similar (P>.05) between BS patients (35 years) and control volunteers (36 years). Serum levels of soluble P-selectin in patients with BS (399 +/- 72 ng/mL) were significantly (P<.001) higher when compared with control subjects (164 +/- 40 ng/mL). In addition, active BS patients (453 37 ng/mL) had significantly (P<.001) elevated levels of soluble P-selectin than those in inactive period (341 +/- 52 ng/mL). This study clearly demonstrated that serum Soluble P-selectin levels are increased in BS patients when compared with control Subjects, Suggesting a modulator role for soluble P-selectin during the Course of platelet activation and therefore, atherothrombogenesis formation in BS, especially in active disease.