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Objective.Behçet disease (BD) is a multifactorial disease in which infectious agents have been proposed as triggers in genetically predisposed individuals. The aim of our study was to investigate the role of innate immunity receptors, specifically the nucleic acid sensors, in susceptibility to BD.Methods.Seventy-four tag single nucleotide polymorphisms (tSNP) selected in 9 candidate genes (DDX58, IFIH1, TLR3, TLR7, TLR8, AIM2, IFI16, ZBP1, and TLR9) were genotyped in 371 patients and 854 controls. Assays of mRNA expression and allele-specific transcript quantification (ASTQ) were performed in 110 and 50 controls, respectively.Results.Patients and controls were genotyped and 2 tSNP (rs6940 in IFI16 and rs855873 in AIM2) were associated with BD. To confirm this association, these tSNP were genotyped in 850 additional controls, and the total cohort was randomly divided into 2 cohorts. The association of these 2 tSNP with the disease remained in both cohorts. One haplotype (rs6940T-rs855873G) was identified as a risk factor (OR 1.41, 95% CI 1.06–1.86, p = 0.015), and another (rs6940A-rs855873A) as a protective factor (OR 0.65, 95% CI 0.47–0.90, p = 0.009). Samples with the risk haplotype had lower IFI16 expression levels than samples with the protective (0.99 ± 0.29 vs 1.23 ± 0.50, p = 0.022). Consistently, in the ASTQ assays performed with the nonsynonymous rs6940 SNP, the risk allele had lower IFI16 expression levels than the protective (p = 0.027).Conclusion.Our findings suggest association of IFI16, a cytosolic sensor of dsDNA and mediator of the AIM2 inflammasome-dependent pathway, in susceptibility to BD. Differences genetically determined in the levels of this molecule could be the cause of this association.

The functional variant R620W of the protein tyrosine phosphatase non receptor-22 (PTPN22) gene plays an important role in susceptibility to several immuno-mediated pathologies. Behçet's disease (BD) is a complex disease related to the immune system with a demonstrated genetic base. The HLA class I genes are the most important genetic factors in BD although other genes are also involved in the susceptibility to this disease. The PTPN22 has been proposed as a candidate gene in BD but this association has not been clearly demonstrated yet. The aim of this study was to assess the association of PTPN22 with BD.A cohort composed of 404 Spanish BD patients and 1517 unrelated healthy individuals ethnically matched was genotyped in rs2476601 (R620W). Five tag SNPs: rs1217412, rs2476599, rs3789607, rs3765598 and rs1217419 (spanning a 57 Kb region between 3'UTR and 5'UTR) and rs2488457 (located at the promoter region) were also studied in order to perform a screening of the complete gene. Genotyping was performed using TaqMan® assays. The rs2476601 data were included in a meta-analysis together with those published till the date. The rest of SNPs were used in a case-control study.No evidence of the association of rs2476601 with BD in the meta-analysis (P = 0.504 in the model of alleles) was found. In the case-control study, no statistically significant differences were observed when comparing the distribution of variants in patients and controls.Our results do not support a major role of the PTPN22 gene in BD.

Behçet's disease (BD) is an immune-mediated and complex disease associated with HLA class I and other genes. The aim of this study was to contribute to a better understanding of the relationship of the 32-bp deletion in the CCR5 gene (CCR5Δ32) and this disease by conducting a case-control study in the Spanish population and also a meta-analysis including all the studies available to date.A cohort composed of 348 BD Spanish patients and 477 unrelated healthy and ethnically matched individuals were genotyped in CCR5Δ32 using polymerase chain reaction (PCR) and capillary electrophoresis with fluorescent detection. In the meta-analysis, data from a total of seven populations extracted from four previous studies along with data of the present study were included.Regarding the case-control study, no statistically significant differences were observed when the patient and control groups were compared (allelic model: 0.07 in patients vs. 0.06 in controls, p=0.303). In the meta-analysis, no evidence of association of the CCR5Δ32 polymorphism with BD was observed (pMH=0.091; OR=1.22; 95%CI 0.98 to 1.52 in the allelic model).The results of this meta-analysis discard a major role of the CCR5Δ32 polymorphism in BD.

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. Recently, an association of variants of the JAK1 and TNFAIP3 genes with the disease has been reported in the Chinese Han population. The aim of the present work was to asses whether the association described in Asian populations is replicated in Europeans.This study includes a total of 1155 Spanish subjects of European origin (372 BD and 783 unrelated healthy individuals). Patients were recruited from different hospitals and controls were collected in the same geographic regions and they matched with patients in age and gender. A total of five SNPs, two in the JAK1 gene: rs2780815 and rs310241 and the other three in the TNFAIP3: rs10499194, rs9494885 and rs610604, were included in this study. The genotyping of these SNPs was performed using a real time PCR system (TaqMan® SNP Genotyping Assays).No statistically significant differences were found when the patient and control groups were compared. The distribution of the risk alleles was similar in patients with and without eye manifestations and in patients with and without HLA-B*51.The association of variants of the genes JAK1 and the TNFAIP3 with BD which has been described in the Chinese population was not replicated in Europeans.

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.

Introduction According to genome wide association (GWA) studies as well as candidate gene approaches, Behçet’s disease (BD) is associated with human leukocyte antigen (HLA)-A and HLA-B gene regions. The HLA-B51 has been consistently associated with the disease, but the role of other HLA class I molecules remains controversial. Recently, variants in non-HLA genes have also been associated with BD. The aims of this study were to further investigate the influence of the HLA region in BD and to explore the relationship with non-HLA genes recently described to be associated in other populations. Methods This study included 304 BD patients and 313 ethnically matched controls. HLA-A and HLA-B low resolution typing was carried out by PCR-SSOP Luminex. Eleven tag single nucleotide polymorphisms (SNPs) located outside of the HLA-region, previously described associated with the disease in GWA studies and having a minor allele frequency in Caucasians greater than 0.15 were genotyped using TaqMan assays. Phenotypic and genotypic frequencies were estimated by direct counting and distributions were compared using the χ2 test. Results In addition to HLA-B*51, HLA-B*57 was found as a risk factor in BD, whereas, B*35 was found to be protective. Other HLA-A and B specificities were suggestive of association with the disease as risk (A*02 and A*24) or protective factors (A*03 and B*58). 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. Conclusion Different HLA specificities are associated with Behçet’s disease in addition to B*51. Other non-HLA genes, such as IL23R and IL-10, play a role in the susceptibility to the disease., This work was supported by Fondo de Investigaciones Sanitarias (10/1701), Fondos FEDER, Plan Andaluz de Investigación (CTS-0197 and CTS-180), Red Enfermedades Inflamatorias y Reumáticas RD08/0075/0013 and Consejería de Salud de la Junta de Andalucía (PI0411/2010). LOF is the recipient of a fellowship (FI11/00547).

Behcet disease (BD) is a multifactorial disorder with a highest prevalence among people with Mediterranean or Asian ancestry having association with HLA-B51 and other HLA and non-HLA loci.1–4 Very recently, one genome-wide association study (GWAS) identified the GIMAP locus, which encoded proteins involved in development of the T and B lymphocytes, as associated with the disease in the Asian populations.5 To investigate whether this association is replicated in Europeans, a total of 1086 (326 patients and 760 controls) Spanish individuals of European origin were genotyped after obtaining written informed consent and approval from the local ethical committees of all the institutions involved. Patients fulfilled the 1990 International Study Group classification criteria for Behcet’s disease,6 and the group was composed of 44.5% men with the following clinical features: 100% had oral ulcers, 63.6% genital ulcers, 58.7% uveitis, 48% arthritis, 20.2% vascular, 21.9% neurological and 19.2% gastrointestinal involvement. Regarding HLA association, in addition to B*51 (p

Background Behcet9s disease (BD) has been consistently associated with HLA class I molecules, specifically, with HLA-B51. However, the role of others HLA class I molecules remains controversial. The current methods of genotyping permit to deduce the HLA typing of a large number of individuals by imputation by using data obtained from high throughput platforms. This approach has improved the knowledge of the association of HLA with the susceptibility to immune-mediated diseases. Objectives Review of the association of HLA region with BD by comprehensive reanalysis with using a novel imputation method [1,2]. Methods The HLA typings of 1794 individuals (277 patients and 1517 healthy controls) were imputed from SNPs genotyping data obtained by Human Immuno DNA Analysis BeadChip Kit (Immunochip). The statistical analyses were performed with PLINK and R. Results The strongest association signals were observed in the HLA-B region, specifically, rs1050502 represented the highest peak (p=7.73 x 10 -24 , OR=4.029, 95%CI 3.123 to 5.198). According to the analysis performed, the amino-acid positions 97 in the HLA-B and 66 HLA-A molecules are the most relevant for the disease susceptibility. Conclusions HLA-B and HLA-A are associated with the susceptibility to BD References Raychauduri S, Sandor C, Stahl EA, et al. (2012) Five amino acids in three HLA proteins explain most of the association between MHC and seropositive rheumatoid arthritis. Nat Gen 44,291-296 Jia X, Han B, Onengut-Gumuscu S, et al. (2013) Imputing amino acid polymorphisms in human leukocyte antigens. PloS one 8, e64683 Disclosure of Interest None declared