Thrombophilic risk factors and homocysteine levels in Behçet's disease in eastern Spain and their association with thrombotic events.

Behçet's disease (BD) is a chronic inflammatory disorder in which thrombosis occurs in about 30% of patients. The prothrombotic mechanisms are unknown. Thrombophilic defects and hyperhomocysteinaemia may be involved in the pathogenesis of thrombotic events, although results have been controversial. Moreover, no information is available on this issue for eastern Spain. We studied the prevalence of inherited and acquired thrombophilic risk factors in 79 patients with BD (43 men, 36 women) who had (n = 23) or did not have (n = 56) thrombosis, and in 84 healthy control subjects (42 men, 42 women). Risk factors examined were antithrombin, protein C and protein S levels, factor V Leiden, the prothrombin G20210A mutation, the methylenetetrahydrofolate reductase C677T polymorphism, and acquired thrombophilic risk factors, including anticardiolipin antibodies, lupus anticoagulant, and serum homocysteine levels. There were no differences between patients and controls in any of the parameters studied. When we studied BD patients with and without thrombotic events, the only thrombophilic defect that differed was the prothrombin G20210A mutation: Three out of 23 patients with thrombosis were carriers, compared with none of 56 patients without thrombosis (p = 0.022). Two of the three carriers developed catastrophic or recurrent thrombotic episodes; one was a homozygous carrier of the G20210A prothrombin mutation and the other was doubly heterozygous for the G20210A prothrombin mutation and factor V Leiden. A meta-analysis demonstrated an association of factor V Leiden and prothrombin mutation with thrombosis in BD. When studies from Turkey were excluded from the meta-analysis, only the prothrombin G20210A mutation was associated with thrombosis.

Haemorheological alterations in Behçet's disease are not related to a tendency for venous thrombosis.

INTRODUCTION: Behçet's disease is associated with an increased risk of thrombosis, although the prothrombotic mechanisms are unclear. Alterations in blood rheology, particularly increased erythrocyte aggregation, might play a role in the development of such thrombotic events. MATERIALS AND METHODS: We measured plasma lipids, fibrinogen, haematocrit, erythrocite aggregation, erythrocyte deformability, blood viscosity, plasma viscosity and erythrocyte indexes in patients with a nonactive disease at sampling, and in a well-matched control group. The patient group comprised 42 patients with BD (21 male, 21 female aged 43+/-12 years) and the control group comprised 46 healthy volunteers (23 male, 23 female aged 45+/-13 years). Twelve of the 42 patients with BD had a previous documented history of deep vein thrombosis at least 6 months before entering the study, and the other 30 did not. RESULTS: Compared with controls, patients showed statistically higher fibrinogen concentrations (P=0.001), plasma viscosity (P=0.002), blood viscosity (P=0.006) and erythrocyte aggregation, both at stasis (P=0.001) and at a low shear rate (P=0.002): the other rheological parameters were not statistically significant. No differences were observed in the rheological parameters when patients with and without previous thrombotic episodes were compared. CONCLUSIONS: Although patients with BD show a moderate hyperviscosity syndrome, possibly related to chronic inflammation, this does not seem to play a role in the development of thrombotic events.