PLA1/A2 polymorphism of the platelet glycoprotein receptors IIIA in Behçet's disease.

Objectives: To investigate potential associations between the PlA1/A2 polymorphism of the platelet glycoprotein receptor IIIA (GpIIIa) gene and venous thrombosis and other clinical manifestations in Italian patients with Behçet's disease (BD).

Methods: Two hundred consecutive Italian patients satisfying the International Study Group criteria for BD who were followed up for seven years and 241 healthy Italian age- and gender-matched blood donors were molecularly genotyped for the PlA1/A2 polymorphism of the platelet GpIIIa gene; 118 and 117 of the 200 BD patients were also respectively genotyped for factor V Leiden and prothrombin gene G20210A polymorphisms. A standard microlymphocytotoxicity technique was used to type serological HLA class B51. The patients were grouped on the basis of the presence or absence of clinical manifestations. The diagnoses of deep vein thrombosis (DVT) and superficial thrombophlebitis were initially made clinically, and then confirmed by means of ultrasonography or contrast venography. The distribution of the PlA1/A2 genotype was investigated, and odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated.

Results: The allele and genotype frequency of the PlA1/A2 polymorphism were not significantly different in the BD patients and controls, but the PlA2 allele was significantly more frequent in the BD patients with DVT than the controls (p=0.023; Pcorr=0.046; OR 2.0, 95% CI 1.1-3.7). There were no associations between thrombotic events and the PlA1/A2 polymorphism in the BD patients carrying factor V Leiden or prothrombin gene G20210A mutations. The PlA2 allele was significantly less frequent in the BD patients with genital genital ulcers than in those without (26.9% vs. 43.2%; p=0.022; P corr 0.044; OR 0.48, CI 0.27-0.88).

Conclusions: The PlA1/A2 polymorphism of the GpIIIa gene was associated with DVT in our Italian BD patients, but does not seem to increase the risk of DVT due to factor V Leiden or prothrombin gene G20210A mutations. There was a negative association between the A2 allele and genital ulcers.