Project description:IntroductionThe knowledge of the aetiology of Behçet disease (BD), an immune-mediated vasculitis, is limited. HLA-B, mainly HLA-B51, and HLA-A molecules are associated with disease, but the ultimate cause of this association remains obscure. There is evidence that NK cells participate in the etiopathology of BD. NK cells have activator and inhibitor surface receptors, like the KIR and the NKG2 families. Classical HLA-class I molecules (A, B and C) are keys in the activity control of the NK because they are KIR ligands. Most NKG2 receptors bind HLA-E, which presents only nonapeptides derived from the signal peptide of other class-I molecules.ObjectiveThis study investigates the contribution of the pair HLA-E and ligand, nonapeptide derived from the 3-11 sequence of the signal peptides of class I classical molecules, to the susceptibility to BD.MethodsWe analyzed the frequency of the HLA-derivated nonapeptide forms in 466 BD patients and 444 controls and an HLA-E functional dimorphism in a subgroup of patients and controls. Results: In B51 negative patients, the frequency of VMAPRTLLL was lower (70.4% versus 80.0% in controls; P=0.006, Pc=0.04, OR=0.60, 95%CI 0.41-0.86), and the frequency of VMAPRTLVL was higher (81.6% versus 71.4% in controls; P=0.004, Pc=0.03, OR=1.78, 95%CI 1.20-2.63). In homozygosity, VMAPRTLLL is protective, and VMAPRTLVL confers risk. The heterozygous condition is neutral. There were no significant differences in the distribution of the HLA-E dimorphism.DiscussionOur results explain the association of BD with diverse HLA-A molecules, reinforce the hypothesis of the involvement of the NK cells in the disease and do not suggest a significant contribution of the HLA-E polymorphism to disease susceptibility.
Project description:IntroductionBehçet's disease (BD) as systemic vasculitis of unknown etiology is associated with HLA-B*51 in European and Asian populations. HLA-A*26 was claimed as an additional BD susceptibility marker in Japanese and Greek patients. This study was performed to test for HLA associations in HLA-B*51 negative German and Turkish BD populations.MethodsIn total, 65 German and 46 Turkish patients lacking HLA-B*51 were analyzed in comparison to healthy HLA-B*51 negative Germans (n = 1500) and Turks (n = 130). HLA-A/B genotypes were determined by SSOP. P-values with correction for multiple testing (p(c)), χ2-test and odds ratio (OR) were used for statistical evaluation.ResultsHLA-A*26 was significantly more frequent in HLA-B*51- German patients [p(c) = 0.0076, OR = 3.23, 95% CI 1.63 to 6.39] than in respective controls. HLA-A*26 was also elevated in a smaller group of Turkish patients versus the controls. Significant association of HLA-Bw4 with isoleucine at amino-acid position 80 (HLA-Bw4-80I) was found in the HLA-B*51(-) German cohort of BD patients [p(c) = 0.0042, OR = 2.35, 95% CI 1.41 to 3.93) and in the Turkish patients in comparison to the respective controls [p = 0.025, OR = 2.17, 95% CI 1.09 to 4.31]. On the contrary, HLA-Bw4-80 T was reduced in both HLA-B*51(-) BD patient cohorts.ConclusionsThe study shows a significant association of HLA-Bw4-80I present on HLA-B*51 as well as on other B-locus molecules with BD. This indicates that distinctive Bw4 epitopes on HLA-B locus molecules could play a role in BD pathogenesis. The study also indicates an association with HLA-A*26 in German and Turkish BD patients as a genetic risk factor independent of HLA-B*51.
Project description:ImportanceAlthough experimental studies support the hypothesis that exposure of infectious agents may trigger an aberrant immune response and contribute to noninfectious uveitis, the association of a definite pathogen with human noninfectious uveitis conditions appears not to have been well established in a population.ObjectiveTo evaluate associations of tuberculosis infection with risk of several noninfectious uveitis conditions.Design, setting, and participantsThese mendelian randomization and observational analyses were conducted with the genetic data of a Chinese cohort enrolled between April 2008 and January 2018 and a Japanese cohort enrolled between January 2002 and June 2009. We recruited participants for T-SPOT.TB (Oxford Immunotec) assays between July and November 2019. The Chinese cohort included patients with uveitis associated with Behçet disease or other uveitis conditions and control participants. The Japanese cohort and the group given T-SPOT.TB assays included individuals with Behçet disease and control participants. Data analyses for this study were completed from July 2019 to January 2020.ExposuresGenetic variants associated with tuberculosis as natural proxies for tuberculosis exposure.Main outcomes and measuresThe primary outcome was the odds ratio (OR) for Behçet disease, estimated by an inverse variance weighted mean of associations with genetically determined tuberculosis susceptibility. The T-SPOT.TB positivity rate was examined in individuals with Behçet disease and compared with that of control participants.ResultsThe Chinese cohort included 999 patients with uveitis associated with Behçet disease, 1585 with other uveitis conditions, and 4417 control participants. The Japanese cohort included 611 individuals with Behçet disease and 737 control participants. The group given T-SPOT.TB assays included 116 individuals with Behçet disease and 121 control participants. Of the Chinese individuals with Behçet disease and control participants, 2257 (41.7%) were female and the mean (SD) age was 35.4 (12.5) years. In the Japanese cohort, 564 (41.8%) were female and the mean (SD) age was 39.1 (12.7) years. Genetically determined tuberculosis susceptibility was associated with an increased risk for Behçet disease. The OR for Behçet disease per 2-fold increase in tuberculosis incidence was 1.26 (95% CI, 1.12-1.43; P = 1.47 × 10-4). Replication using the Japanese cohort yielded similar results (OR, 1.16 [95% CI, 1.08-1.26]). In T-SPOT.TB assays, having a positive result, indicating a history of tuberculosis infection, was found to be an independent risk factor for Behçet disease (OR, 2.26 [95% CI, 1.11-4.60]).Conclusions and relevanceThese human genetic and biomarker data demonstrated that tuberculosis exposure was a risk factor for Behçet disease. This study provides novel evidence linking an infectious agent to the risk of a noninfectious uveitis condition.
Project description:Behçet's disease (BD) is a multifactorial disorder associated with the HLA region. Recently, the ERAP1 gene has been proposed as a susceptibility locus with a recessive model and with epistatic interaction with HLA-B51. ERAP1 trims peptides in the endoplasmic reticulum to optimize their length for MHC-I binding. Polymorphisms in this gene have been related with the susceptibility to other immune-mediated diseases associated to HLA class I. Our aim was, the replication in the Spanish population of the association described in the Turkish population between ERAP1 (rs17482078) and BD. Additionally, in order to improve the understanding of this association we analyzed four additional SNPs (rs27044, rs10050860, rs30187 and rs2287987) associated with other diseases related to HLA class I and the haplotype blocks in this gene region. According to our results, frequencies of the homozygous genotypes for the minor alleles of all the SNPs were increased among patients and the OR values were higher in the subgroup of patients with the HLA-B risk factors, although differences were not statistically significant. Moreover, the presence of the same mutation in both chromosomes increased the OR values from 4.51 to 10.72 in individuals carrying the HLA-B risk factors. Therefore, although they were not statistically significant, our data were consistent with an association between ERAP1 and BD as well as with an epistatic interaction between ERAP1 and HLA-B in the Spanish population.
Project description:Behçet's Disease (BD) pathogenesis remains unclear, but some genetic loci and environmental factors are proposed to play a role. Here, we investigate the association of the endoplasmic reticulum aminopeptidase-1 (ERAP1) gene variants and HLA-B*51 with BD susceptibility and clinical manifestations in Iranian patients. In the study, 748 BD patients and 776 healthy individuals were included. The MGB-TaqMan Allelic Discrimination method was used to genotype 10 common missense single nucleotide polymorphisms (SNPs) and one intronic SNP in the ERAP1 gene region. We found no significant association between the 11 SNPs and BD in allelic and genotypic association tests. However, rs30187 showed the strongest association with BD in the recessive genotype model of the risk T allele in HLA-B*51 carriers. Although this became insignificant after correcting for multiple comparisons, the homozygous rs30187 risk allele genotype (TT) increased disease susceptibility in HLA-B*51 carriers in epistasis analysis, and the rs30187 TT recessive genotype showed a significant association with risk of cardiac involvement in the all patients and articular involvements in HLA-B*51 positive patients. Our findings suggest that gene-gene interactions between HLA-B*51 and ERAP1 variants is important for BD development, however, ERAP1 variants which interact with HLA-B*51 may differ among disease phenotypes or populations.
Project description:IntroductionEndoplasmic reticulum aminopeptidase-1 (ERAP1) protein is highly polymorphic with numerous missense amino acid variants. We sought to determine the naturally occurring ERAP1 protein allotypes and their contribution to Behçet's disease.MethodsGenotypes of all reported missense ERAP1 gene variants with 1000 Genomes Project EUR superpopulation frequency >1% were determined in 1900 Behçet's disease cases and 1779 controls from Turkey. ERAP1 protein allotypes and their contributions to Behçet's disease risk were determined by haplotype identification and disease association analyses.ResultsOne ERAP1 protein allotype with five non-ancestral amino acids was recessively associated with disease (p=3.13×10-6, OR 2.55, 95% CI 1.70 to 3.82). The ERAP1 association was absent in individuals who lacked HLA-B*51. Individuals who carry HLA-B*51 and who are also homozygous for the haplotype had an increased disease odds compared with those with neither risk factor (p=4.80×10-20, OR 10.96, 95% CI 5.91 to 20.32).DiscussionThe Behçet's disease-associated ERAP1 protein allotype was previously shown to have poor peptide trimming activity. Combined with its requirement for HLA-B*51, these data suggest that a hypoactive ERAP1 allotype contributes to Behçet's disease risk by altering the peptides available for binding to HLA-B*51.
Project description:BackgroundSeveral studies have reported the association of Behcet disease (BD) with the risk of diverse kinds of cancers. However, its association is controversial. Therefore, we conducted a bioinformatics-analysis to explore any possible association.MethodsWe obtained relevant findings published before October 2018 through literature survey of the PubMed, EMBASE, and Web of Science databases. STATA 12.0 software was used for statistical analysis.ResultsAfter screening, the meta-analysis comprised 5 studies. We observed a significant positive association between BD and enhanced malignancy risk (pooled relative risk [RR], 1.19; 95% confidence interval [CI]: 1.09-1.30), especially for hematological cancer (pooled RR, 2.58; 95% CI: 1.61-3.55) and thyroid cancer (pooled RR, 1.25; 95% CI: 1.04-1.47). However, high heterogeneity was also observed in the results (I?=?81.3%). Subgroup analysis indicated that female BD patients from Korean population are at highest predisposition to overall malignancy. Besides, publication bias was not observed with our choice of surveys.ConclusionWe conclude that patients suffering from BD have an overall increased risk for malignancy. Greater numbers of exhaustive temporal studies are essential for definitive inferences.
Project description:BackgroundBehçet disease is a prototypical systemic autoimmune disease, caused by a complex interplay between environmental and genetic factors. The transmembrane immunoglobulin and mucin domain-3 (TIM-3) is a distinct member of the TIM family that is preferentially expressed on Th1 cells and plays a role in Th1-mediated autoimmune or inflammatory diseases, such as Behçet disease.ObjectiveThe aim of this study was to test the potential association between TIM-3 gene polymorphisms and Behçet disease.MethodsTwo single-nucleotide polymorphisms of TIM-3 (rs9313439 and rs10515746) were genotyped in 212 patients with Behçet disease and 200 healthy controls. Typing of the polymorphisms was performed using multiplex PCR amplification.ResultsThere were no significant differences in allele and genotype frequencies between the Behçet disease patients and controls who were successfully genotyped. Similar results were also found after stratification by gender, age, or clinical features.Study limitationsLack of studies on various racial or ethnic groups and small sample size.ConclusionThis study failed to demonstrate any association between the tested TIM-3 polymorphisms and Behçet disease.
Project description:Behçet's disease (BD) is an immune-mediated systemic disorder with a well-established genetic base. In a previous study, using a next generation sequencing approach, we found many rare variants and some functional polymorphisms in genes related to autoinflammatory syndromes (AID): CECR1, MEFV, MVK, NLRP3, NOD2, PSTPIP1 and TNFRSF1A in our BD cohort. Our strategy did not allow us to establish either number of patients with variants, proportion of individuals accumulating them or relationship with other genetic factors. With the goal to answer these questions, the individual samples were sequenced. Additionally, three functional polymorphisms: NLRP3 p.Gln703Lys, NOD2 p.Arg702Trp and p.Val955Ile were genotyped using TaqMan assays. A total of 98 patients (27.6%) carried at least one rare variant and 13 of them (3.7%) accumulated two or three. Functional regression model analysis suggests epistatic interaction between B51 and MEFV (P = 0.003). A suggestive protective association of the minor allele of NOD2 p.Arg702Trp (P = 0.01) was found in both, B51 positive and negative individuals. Therefore, a high percentage of patients with BD have rare variants in AID genes. Our results suggest that the association of MEFV with BD could be modulated by the HLA molecules; whereas the protective effect of NOD2 p.Arg702Trp would be independent of HLA.
Project description:Individuals with Behçet's disease suffer from episodic inflammation often affecting the orogenital mucosa, skin and eyes. To discover new susceptibility loci for Behçet's disease, we performed a genome-wide association study (GWAS) of 779,465 SNPs with imputed genotypes in 1,209 Turkish individuals with Behçet's disease and 1,278 controls. We identified new associations at CCR1, STAT4 and KLRC4. Additionally, two SNPs in ERAP1, encoding ERAP1 p.Asp575Asn and p.Arg725Gln alterations, recessively conferred disease risk. These findings were replicated in 1,468 independent Turkish and/or 1,352 Japanese samples (combined meta-analysis P < 2 × 10(-9)). We also found evidence for interaction between HLA-B*51 and ERAP1 (P = 9 × 10(-4)). The CCR1 and STAT4 variants were associated with gene expression differences. 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.