In the current study of Behçet disease (BD), nonsynonymous variants (NSVs) identified by deep exonic resequencing of 10 genes found by GWAS (IL10, IL23R, CCR1, STAT4, KLRK1, KLRC1, KLRC2, KLRC3, KLRC4, and ERAP1) and 11 genes selected for their role in innate immunity (IL1B, IL1R1, IL1RN, NLRP3, MEFV, TNFRSF1A, PSTPIP1, CASP1, PYCARD, NOD2, and TLR4) were evaluated for BD association.
The evaluation of the IL-2 gene polymorphism (p=0.0065) and IL-10 gene polymorphism (p=0.0483) distributions with respect to age of BD onset revealed a statistically significant distribution.
Thus, this study aimed to investigate the associations between IL-6 and IL-10 promoter single-nucleotide polymorphisms (SNPs) and the susceptibility to BD and their implication on plasma levels.
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.
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).
Three risk loci shared with ankylosing spondylitis and psoriasis (the MHC class I region, ERAP1 and IL23R and the MHC class I-ERAP1 interaction), as well as two loci shared with inflammatory bowel disease (IL23R and IL10) implicate shared pathogenic pathways in the spondyloarthritides and Behçet's disease.
Rare IL10 coding variants were not detected in BD patients, but we identified 28 known single nucleotide polymorphisms with minor allele frequencies ranging from 0.010 to 0.390, and five novel non-coding variants in five heterozygous cases. ss836185595, located in the IL10 3' untranslated region, was also detected in one Iranian control individual and therefore is not specific to BD.
In IL10, rs1518111 was nominally associated with BD before and after adjustment for population stratification (odds ratio [OR] for T allele 1.20, 95% confidence interval [95% CI] 1.02-1.40, unadjusted P [P(unadj) ] = 2.53 × 10(-2) ; adjusted P [P(adj) ] = 1.43 × 10(-2) ), and rs1554286 demonstrated a trend toward association (P(unadj) = 6.14 × 10(-2) ; P(adj) = 3.21 × 10(-2) ).
Our findings not only confirmed the association of IL10/rs1800871 and IL23R-IL12RB2/rs924080 with BD but also identified 2 susceptibility single nucleotide polymorphisms in IL10 and IL23R-IL12RB2 (rs3024490 and rs12141431) with BD in Han Chinese.
Non-HLA genetic associations such as endoplasmic reticulum aminopeptidase 1 (ERAP1), interleukin 23 receptor (IL23R) and IL10 variations suggest that BD shares susceptibility genes and inflammatory pathways with spondyloarthritis.
Our study indicates that functional TNF-α, IL10 genotypes or combined TNF-α, IL10 genotypes do not play a role in BS susceptibility in Turkish BS patients.
Regarding the non-HLA genes, the three SNPs located in IL23R and one of the SNPs in IL10 were found to be significantly associated with susceptibility to BD in our population.