Furthermore, the existence of a linkage disequilibrium between HLA-DQB1*0501 and TAP2B in our patients suggests that the gene conferring susceptibility for BD is inherited as an extended haplotype in the population studied.
These facts suggest that the pathogenic gene of Behçet's disease is not the HLA-C gene (HLA-Cw*14 and/or HLA-Cw*15) but the HLA-B gene (HLA-B51) itself or a non-HLA gene residing in the centromeric side of the HLA-B gene rather than in the telomeric side around the HLA-C gene.
These facts suggest that the pathogenic gene of Behçet's disease is not the HLA-C gene (HLA-Cw*14 and/or HLA-Cw*15) but the HLA-B gene (HLA-B51) itself or a non-HLA gene residing in the centromeric side of the HLA-B gene rather than in the telomeric side around the HLA-C gene.
No differences were found between either of the patient groups and the healthy control group, indicating that LMP7 allelic variation may not contribute to the pathogenesis of either Behçet's disease or sarcoidosis.
HLA-B51 molecules themselves may be responsible, at least in part, for the neutrophil hyperfunction in Behçet's disease; a significant correlation was observed between the neutrophil hyperfunction and the possession of HLA-B51 phenotype, regardless of the presence of the disease, in both humans and HLA-B transgenic mice.
However, polymorphic analyses of the TNFB gene and Tau-a microsatellite between the HLA-B and TNF genes indicate that the pathogenic gene of BD is not the HLA-B51 gene itself but another gene located around the HLA-B gene.
HLA-C genotyping by the PCR-SSP method also suggests that the BD pathogenic gene is not the HLA-C gene itself but other gene located near the HLA-B gene.
Furthermore, the microsatellite allele consisting of 6 repetitions of GCT/AGC (MICA A6 allele) was present at a significantly higher frequency in the BD patient group than in the control group and a significant fraction of B51-negative patients were positive for this MICA A6 allele.