HLA-B51 and its allelic types in association with Behçet's disease and recurrent aphthous stomatitis in Korea.

OBJECTIVE This case-control study was undertaken to evaluate the association of HLA-B51 antigen and its allelic types with Behçet's disease (BD) and with recurrent aphthous stomatitis (RAS), to investigate the degree of this association with diagnostic types and clinical variables of BD. METHODS The DNA typing of HLA-B51 by nested PCR-SSP was performed in 61 patients with BD, 56 patients with RAS, and in 70 healthy controls. Also, blind quality control study was done to assess the accuracy of nested PCR-SSP in HLA-B51-positive and negative BD patients on the microlymphocytotoxicity. In addition, direct DNA sequencing analysis was carried out in HLA-B51-positive individuals. RESULTS The outcome of nested PCR-SSP showed 100% concordance with those of the microlymphocytotoxicity. The prevalence of HLA-B51 in patients with BD was 55.7%, 16.1% in patients with RAS, and 15.7% in healthy controls. According to the diagnostic types of BD, all ten patients with complete BD had HLA-B51 antigen, and 47.1% in patients with incomplete BD (p = 0.002). In addition, the prevalence of HLA-B51 was statistically significant in patients with BD who had uveitis (p = 0.003) or erythema nodosum (p = 0.042). Direct DNA sequencing analysis revealed that the major allelic types in BD, RAS, and in healthy control were mostly HLA-B*51011. CONCLUSIONS Compared to patients with RAS or healthy controls, prevalence of HLA-B51 in the Korean patients with BD was much higher. The BD patients with B51 seemed to be susceptible for manifesting uveitis, erythema nodosum, and the full-blown syndrome as complete BD. Therefore the presence of HLA-B51 antigen in BD patients would be a genetic marker for the severe disease. In addition, there was no difference on the major allelic types of HLA-B51 in BD, RAS, and in healthy control.