[Behçet's disease and HLA antigens--an association with a new specificity recognized by a monoclonal antibody].

In this study, HLA antigen frequencies of 37 patients with Behçet's disease were investigated. A significant association with HLA-B 51 was confirmed (56.8% compared with 10.0% controls, P less than 0.0001, relative risk (R.R.) = 11.8). Furthermore, significant increases of HLA-DRw 52 (86.1% compared with 50.9% controls, Pc less than 0.05, R.R. = 6.0) and a new specificity detected by a monoclonal antibody, HU-39 (61.1% compared with 25.5% controls, Pc less than 0.05, R.R. = 4.6) were also observed. The serologic specificity of HU-39 was DRw 8 + DRw 12, which has never been defined using alloantisera. Immunochemical analyses indicated that the determinant recognized by HU-39 was borne on the HLA-DR molecule, not on the HLA-DQ molecule. These results suggest that not only HLA-B locus antigens but also HLA-D region antigens, particularly HLA-DR antigens, play a part in the pathogenesis of Behçet's disease. In addition, the usefulness of this monoclonal antibody as tissue typing reagent and the application of monoclonal antibodies to the analysis of disease susceptibility were discussed.