Anticardiolipin antibodies in Behçet's disease: a reassessment.

Objective: To assess the frequency and clinical relevance of anticardiolipin antibodies (aCL) in Behçet's disease (BD).
Methods: IgG, IgM and IgA aCL isotypes were investigated by ELISA in 128 patients with BD, 143 healthy controls and 20 systemic lupus erythematosus (SLE) patients.
Results: The IgA binding index (BI) was slightly elevated in BD compared with healthy controls (120+/-53 vs 107+/-46, P=0.02), whereas IgG and IgM aCL levels were not significantly different (IgG, BD 2.5+/-2.4 G phospholipid (GPL), healthy controls 2.8+/-3.6 GPL, P=0.6; IgM, BD 0.7+/-0.9 M phospholipid (MPL), healthy controls 0.9+/-1.3 MPL, P=0.6). The frequency of aCL positivity was 7% in BD (IgG 0.8%, IgM 1.6%, IgA 4.6%), 50% in SLE and 5.6% in healthy controls. IgA BI was elevated in the HLA-B5-negative group compared with HLA-B5-positive patients (P<0.005). In a literature review, the frequency of aCL was found to be 9.5% in studies from Turkey compared with 25.5% in other series (P<0.0001).
Conclusion: These results do not suggest a primary role for aCL in BD. A significantly lower frequency of aCL in Turkish BD patients than in other series indicate that regional determinants, whether environmental or genetic, might also play a role in controlling aCL production in BD.