Primary association of HLA-B51 with Behçet's disease in Ireland.

AIMS/BACKGROUND While a primary association of HLA-B51 with Behçet's disease (BD) in Japanese and Mediterranean patients supports an immunogenetic predisposition, this link is unclear in north western Europe. This study assessed HLA associations with BD, and HLA-B51 with certain clinical characteristics, in the Republic of Ireland, which has an ethnically homogeneous population. METHODS HLA-A, HLA-B, and HLA-DR typing was performed in 24 BD patients, conforming to International Study Group criteria, and in blood donors, as controls. Patient records were retrospectively reviewed and patients reassessed clinically. RESULTS A highly significant HLA-B51 association (corrected exact p value = 0.002, relative risk = 6.3) with BD was determined, despite a low B51 prevalence (25%) in patients. No other HLA type was associated. There was a significant B51 link with male sex in BD patients but no association with age at first manifestation/diagnosis, eye involvement, cyclosporin A therapy, or poor visual acuity was determined. CONCLUSIONS This study supports a HLA-B51 immunogenetic predisposition, similar to Japanese patients, in Irish BD in an ethnically homogeneous population in north western Europe. However, owing to a low prevalence of B51 positivity in BD patients in Ireland, a multifactorial pathogenesis is suggested.