[Immunogenetic mechanism of Behçet's disease].

In order to investigate the immunogenetic mechanism of Behçet's disease, frequencies of HLA antigens were studied in patients. The subjects consisted of 66 patients and 99 normal controls. A lymphocyte cytotoxicity test was used for typing HLA-A, -B, -C, -DR, -DQ antigens. HLA-DP antigens were analyzed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. A significant increase of HLA-B15 was observed in the patients. In contrast, no significant difference was observed in HLA-Bw52 which possesses only two different amino acids from HLA-B15. On the contrary, frequencies of HLA-A11, HLA-Aw33, HLA-B35, HLA-B44 and HLA-DQw1 were significantly lower in the patients than in the controls. No significant difference was observed in HLA-DP antigens. These results suggest that Behçet's disease involves both disease susceptibility factors and disease resistance factors and that such genetic factors are mapped within or very close to the HLA-B gene in the class I gene region. Additionally class II HLA-DQ antigen is associated with disease resistance factors.