Plasma homocysteine level in patients with Behcet's disease with or without thrombosis

Aim: To find the possible role of plasma homocysteine level as a contributing factor in venous and arterial thrombosis in patients with Behcet's disease (BD). Methods: In a case control study, two groups of BD patients were included: 47 with thrombosis and 49 without thrombosis. All patients fulfilled the International Study Group Criteria for BD and the confirming diagnostic procedures for vascular thrombosis were either Doppler sonography or angiography. Forty-nine controls were selected by consecutive sampling among age and sex matched healthy subjects. Plasma homocysteine level was measured by ELISA in all. The clinical and laboratory characteristics of the disease were compared between the two groups of BD patients. Comparisons were done by ANOVA and Chi square tests; correlations were analyzed with Pearson test. Results: The mean plasma homocysteine level was signi_cantly higher in BD patients (14.9±13.9 μMol/L) than in healthy controls (9.9±6.7 μMol/L), P<0.02. The difference was also significant when comparing the three groups by ANOVA: BD patients with thrombosis (24.2±13.2 μMol/L), BD patients without thrombosis (5.9±7.0 μMol/L), and healthy controls (P<0.0001). We found no correlation between plasma homocysteine level and any organ involvement other than thrombosis. The mean plasma homocysteine level was lower in HLA-B51 positive BD patients (11.6±12.1 vs. 21.7±16.3 μMol/L, P<0.05), but the difference was not significant in those with thrombosis (20.9±13.2 vs. 29.5±12.7 μMol/L, P=0.18). Conclusion: Hyperhomocysteinaemia may be an independent risk factor for vascular thrombosis in patients with BD. This is the first study showing a negative correlation between HLA-B51 and plasma homocysteine level.