The prevalent distribution in a specific geographical area spanning the Mediterranean basin and Asia, the close association with human leukocyte antigen B*51 in different ethnic groups, and the familial clustering of BD are hallmarks accounting for the strong contribution of a genetic background.
Although it has been reported that the MHC class I molecule, HLA-B51, is a risk factor for Behçet's disease (BD), contribution of the tumor necrosis factor (TNF) genes, which are located in the vicinity of the HLA-B locus, to the genetic susceptibility for BD has yet to be elucidated.
Using a state-of-the-art imputation method to analyse the major histocompatibility complex (MHC) region, Ombrello and colleagues narrowed down the association between human leukocyte antigen (HLA)-B51 and Behçet's disease to a model of five amino acids of the HLA-B molecule involved in the binding of the antigen, the interactions with receptors on CD8 T cells and natural killer cells, and the signal peptide of HLA-B, suggesting a crucial role of the cellular cytotoxicity on this disease.
In order to investigate the influence of the MICB gene, located about 120 kb centromeric of the HLA-B gene, on the susceptibility to BD, (CA/TG) dinucleotide repeat microsatellite polymorphism in intron 1 of the MICB gene was investigated among 77 Japanese patients with BD, 60 randomly selected controls and 28 HLA-B51-positive unrelated healthy controls.
Therefore, the goal of this study was to measure the correlation of the IL-10 gene polymorphisms with the susceptibility to Behçet's disease compared with the control group in the Azeri population and to determine the expression of this gene in the two groups.
Although we were not able to formally replicate the association with IL10 and IL23R-IL12RB2, we do report that BD in Iran is strongly associated with HLA-B*51, MICA-A6, and the three HLA-linked SNPs (odds ratio (OR) = 3.38, P = 6.21 × 10(-14); OR = 2.08, P = 1.58 × 10(-13); and OR = 1.67-4.05, P = 1.45 × 10(-04) to 4.79 × 10(-34), respectively).
Furthermore, a positive correlation was observed between IL-10 serum levels and ocular manifestations in BD patients, in contrast to those of IL-17, showing no correlation with the different clinical manifestations.
Behçet's disease (BD) is an immune-mediated and complex disease which has been associated with HLA class I molecules although other genes such as IL23R and IL10 have also been involved in the susceptibility to BD.
This link between BD, a chronic, relapsing, autoinflammatory condition, and a genotype associated with low IL-10 production provides evidence that abnormalities in the genetic control of cytokine levels may be relevant in influencing the immune response in Behçet's disease in some patient groups.
We tested 14 single-nucleotide polymorphisms (SNPs) in 13 genomic loci (excluding the major histocompatibility complex [MHC], IL10, and IL23R-IL12RB2, which have already been associated with BD in Iranians) for allelic and genotypic associations with BD in 973 patients and 828 controls from Iran and performed meta-analyses of the significantly associated markers.
Behçet's disease (BD) susceptibility had been associated with single-nucleotide polymorphisms (SNPs) in IL23R-IL12RB2, IL10, STAT4, or ERAP1 locus in Japanese, Turkish, Chinese, and other populations, but not in a Korean genome-wide association study (GWAS).