A weak association of HLA-B*2702 with Behçet's disease.

This study aimed to analyse the association of HLA-B alleles other than -B51 with Behçet's disease (BD). We also investigated the frequency of HLA-B alleles sharing the same natural killer cell immunoglobulin-like receptor (KIR) binding sequence with HLA-B51. Broad-genotyping of HLA-B locus by PCR-SSOP in 174 Turkish BD patients and 191 healthy controls confirmed the strong association of B*51 with BD (60.9% in BD patients, 24.6% in healthy controls, OR = 4.78). No other HLA-B allele was identified showing an association with BD after adjusting for multiple testing or by using relative predispositional effects (RPE) analysis after the deletion of B*51. HLA-B alleles reacting with the sequence specific oligonucleotide probe 23, which corresponds to the KIR binding site of B*51, were found to be positive in 127 BD patients (73%) and 90 controls (47%) (OR = 3.03, 95% CI 2-4.7). The repeated RPE analysis after separating HLA-B alleles carrying B51-KIR binding sequence as distinct alleles within a broad-type allele group revealed B*2702 allele as the only allele showing an association with BD after the deletion of B*51. Selective increase of B*2702, the only B*27 allele carrying the same KIR binding sequence with B*51, warrants investigation of the possibility of interaction of HLA molecules with KIRs on NK or other T cells in the pathogenesis of BD.