IL2RA Locus Research Articles

Biomedical Data Commons (BMDC) prioritizes B-lymphocyte non-coding genetic variants in Type 1 Diabetes.

The repurposing of biomedical data is inhibited by its fragmented and multi-formatted nature that requires redundant investment of time and resources by data scientists. This is particularly true for Type 1 Diabetes (T1D), one of the most intensely studied common childhood diseases. Intense investigation of the contribution of pancreatic β-islet and T-lymphocytes in T1D has been made. However, genetic contributions from B-lymphocytes, which are known to play a role in a subset of T1D patients, remain relatively understudied. We have addressed this issue through the creation of Biomedical Data Commons (BMDC), a knowledge graph that integrates data from multiple sources into a single queryable format. This increases the speed of analysis by multiple orders of magnitude. We develop a pipeline using B-lymphocyte multi-dimensional epigenome and connectome data and deploy BMDC to assess genetic variants in the context of Type 1 Diabetes (T1D). Pipeline-identified variants are primarily common, non-coding, poorly conserved, and are of unknown clinical significance. While variants and their chromatin connectivity are cell-type specific, they are associated with well-studied disease genes in T-lymphocytes. Candidates include established variants in the HLA-DQB1 and HLA-DRB1 and IL2RA loci that have previously been demonstrated to protect against T1D in humans and mice providing validation for this method. Others are included in the well-established T1D GRS2 genetic risk scoring method. More intriguingly, other prioritized variants are completely novel and form the basis for future mechanistic and clinical validation studies The BMDC community-based platform can be expanded and repurposed to increase the accessibility, reproducibility, and productivity of biomedical information for diverse applications including the prioritization of cell type-specific disease alleles from complex phenotypes.

Predisposition to Graves' disease and Graves' ophthalmopathy by genetic variants of IL2RA.

Previous studies have identified that Th17/Treg cells were involved in the occurrence and development of Graves' disease (GD). This study aimed at clarifying the association between GD susceptibility and nine single nucleotide polymorphisms (SNPs) of Th17/Treg cell-related genes, including IL2RA, miR27a, miR182, and FoxO1. A two-stage association study was performed in 650 GD patients and 1300 healthy controls. PCR-RFLP assays, real-time PCR, and ELISA were performed. In the first stage, association analysis has identified that IL2RA/rs3118470 TT genotype (Pc = 0.027, OR = 1.688) and IL2RA/rs2104286 AA genotype (Pc = 0.027, OR = 1.658) has significantly increased frequencies in patients with GD than control subjects. In the second stage, the result of rs2104286 was consistent with the first-stage results (AA genotype: Pc = 0.006, OR = 1.618). The combined data showed that IL2RA/rs2104286 AA genotype had increased frequencies in patients with GD (Pc = 8.772 × 10-6, OR = 1.636). Stratification analysis also revealed that rs2104286 AA genotype was significantly associated with Graves' ophthalmopathy (GO) susceptibility (Pc = 9.150 × 10-4, OR = 1.851). Functional studies showed that carriers of the rs2104286 AA genotype had lower IL2RA mRNA expression than AG genotype carriers (P = 0.021). Cytokine analyses revealed that the rs2104286 AA genotype individuals had lower IL-10 levels (P = 0.015) and increased IL-17 levels than AG genotype carriers (P = 1.467 × 10-4). In conclusion, our findings suggested that IL2RA/rs2104286 was associated with GD and GO susceptibility in Southwest Chinese Han population, which may be involved in the occurrence of GD and GO by affecting the mRNA expression of IL2RA gene and the cytokine production. KEY MESSAGES: We identified that IL2RA/rs2104286 locus contributed to the predisposition of Graves' disease (GD) and Graves' ophthalmopathy (GO). Functional analyses suggested that IL2RA/rs2104286 may participate in the occurrence of GD and GO by affecting the mRNA expression of IL2RA and cytokine (IL-10 and IL-17) secretion. We found that IL2RA (rs3118470, rs7093069), miR27a/rs895819, miR182/rs76481776, and FoxO1 (rs2297626, rs17592236, rs9549241, rs12585277) loci polymorphisms were not associated with GD susceptibility.

Duplication of the IL2RA locus causes excessive IL-2 signaling and may predispose to very early onset colitis

Single genetic mutations predispose to very early onset inflammatory bowel disease (VEO-IBD). Here, we identify a de novo duplication of the 10p15.1 chromosomal region, including the IL2RA locus, in a 2-year-old girl with treatment-resistant pancolitis that was brought into remission by colectomy. Strikingly, after colectomy while the patient was in clinical remission and without medication, the peripheral blood CD4:CD8 ratio was constitutively high and CD25 expression was increased on circulating effector memory, Foxp3+, and Foxp3neg CD4+ T cells compared to healthy controls. This high CD25 expression increased IL-2 signaling, potentiating CD4+ T-cell-derived IFNγ secretion after T-cell receptor (TCR) stimulation. Restoring CD25 expression using the JAK1/3-inhibitor tofacitinib controlled TCR-induced IFNγ secretion in vitro. As diseased colonic tissue, but not the unaffected duodenum, contained mainly CD4+ T cells with a prominent IFNγ-signature, we hypothesize that local microbial stimulation may have initiated colonic disease. Overall, we identify that duplication of the IL2RA locus can associate with VEO-IBD and suggest that increased IL-2 signaling predisposes to colonic intestinal inflammation.

Genetic Association Study of IL2RA, IFIH1, and CTLA-4 Polymorphisms With Autoimmune Thyroid Diseases and Type 1 Diabetes.

Autoimmune thyroid diseases (AITDs) which include Graves' disease (GD) and Hashimoto's thyroiditis (HT) as well as type 1 diabetes (T1D) are common autoimmune disorders in children. Many genes are involved in the modulation of the immune system and their polymorphisms might predispose to autoimmune diseases development. According to the literature genes encoding IL2RA (alpha subunit of Interleukin 2 receptor), IFIH1 (Interferon induced with helicase C domain 1) and CTLA-4 (cytotoxic T cell antigen 4) might be associated with autoimmune diseases pathogenesis. The aim of the study was to assess the association of chosen single nucleotide polymorphisms (SNPs) of IL2RA, IFIH1, and CTLA-4 genes in the group of Polish children with AITDs and in children with T1D. We analyzed single nucleotide polymorphisms (SNPs) in the IL2RA region (rs7093069), IFIH1 region (rs1990760) and CTLA-4 region (rs231775) in group of Polish children and adolescents with type 1 diabetes (n = 194) and autoimmune thyroid diseases (GD n = 170, HT n = 81) and healthy age and sex matched controls for comparison (n = 110). There were significant differences observed between T1D patients and control group in alleles of IL2RA (rs7093069 T > C) and CTLA-4 (rs231775 G > A). In addition, the study revealed T/T genotype at the IL2RA locus (rs7093069) and G/G genotype at the CTLA-4 locus (rs231775) to be statistically significant more frequent in children with T1D. Moreover, genotypes C/T and T/T at the IFIH1 locus (rs1990760) were significantly more frequent in patients with T1D than in controls. We observed no significant differences between AITD patients and a control group in analyzed SNPs. In conclusion, we detected that each allele T of rs7093069 SNP at the IL2RA locus and G allele of rs231775 SNP at the CTLA-4 locus as well as C/T and T/T genotypes of rs1990760 SNP at the IFIH1 locus are predisposing in terms of T1D development. Thereby, we confirmed that IL2RA, IFIH1, and CTLA-4 gene locus have a role in T1D susceptibility. The analysis of selected SNPs revealed no association with AITDs in a group of Polish children and adolescents.

Functional dissection of the Il2ra superenhancer reveals developmentally regulated and cell type specific elements

Abstract The expression of the IL-2 receptor a chain is tightly regulated during early T cell development and in mature lymphoid populations by either cytokine stimulation or T cell receptor interactions. IL-2Ra expression can be either constitutive, as in some double negative thymocytes and T regulatory cells, or inducible, as in CD4+and CD8+mature T cells. Previously, our lab identified a super-enhancer in the mouse Il2ra locus that extensively bound STAT5 and controlled expression of this gene in mature T cells. To further dissect developmental and cell type specific expression of this super-enhancer, Crispr-Cas9 mediated deletion was used to generate mutant mice lacking either individual or groups of STAT5 binding sites in either the upstream region or the first intron. Deletion of the upstream region led to the absence of CD25 expression in DN2 and DN3 thymocytes as well as a significant reduction of CD25 expression on regulatory T cells, but minimal effect on inducible CD25 expression in mature T cells. Analysis of individual upstream elements in reporter assays revealed a specific element that controlled high activity in DN3 cells and a Treg cell line, with markedly diminished activity in the presence of Notch inhibitors. In contrast, deletion of an intronic region markedly diminished both IL-2 and TCR-induced expression of CD25 in vitro, while having little if any effect on CD25 expression in DN thymocytes or Treg cells. These data reveal that the Il2rasuper-enhancer is composed of multiple elements that preferentially mediate either constitutive or inducible Il2ragene expression. Further analysis of these elements will define mechanisms for regulation and potentially manipulation of CD25 expression in autoimmune and other disease states.

Genetics Coming of Age in Type 1 Diabetes.

Decades of studies demonstrate that ∼50% of risk for type 1 diabetes (T1D) is heritable (1). The first loci linked to T1D were the HLA genes that have the largest effect size of any T1D susceptibility locus, followed by linkage of the insulin VNTR to T1D (2,3). Linkage studies have given way to genome-wide association studies (GWAS) that have identified >50 loci that contribute risk for developing T1D (4). Most of these loci impart modest relative risk for T1D (odds ratio ≤2.0) and together with HLA account for ∼80% of the heritability of T1D (5). The question remains: have GWAS delivered in terms of our ability to understand the causes of T1D and thus identify therapeutic targets or predict disease course? GWAS have revealed several important aspects of T1D disease etiology. First, the majority of genes associated with T1D function in the immune system, underscoring the immune basis of disease initiation and progression (6). Second, GWAS have identified pathways that are important in disease pathogenesis, such as variants in the interleukin-2 (IL-2) signaling pathway ( IL2 , IL2RA , and PTPN2 loci) that are associated with disease (4,7,8). Third, T1D GWAS studies have identified a shared genetic architecture with other autoimmune diseases (e.g., PTPN22 , CTLA4 , SH2B3 , TYK2 , and CLEC16A loci), indicating common pathogenic mechanisms and the possibility of repurposing therapies for T1D that are in use for other autoimmune diseases. Additionally, genotype-phenotype studies have provided important windows into disease pathogenesis by revealing alterations in B-cell and T-cell development, tolerance checkpoints, regulatory T-cell fitness, …

Dynamic demethylation of the IL2RA promoter during in vitro CD4+ T cell activation in association with IL2RA expression

ABSTRACTIL2RA, a subunit of the high affinity receptor for interleukin-2 (IL2), plays a crucial role in immune homeostasis. Notably, IL2RA expression is induced in CD4+ T cells in response to various stimuli and is constitutive in regulatory T cells (Tregs). We selected for our study 18 CpGs located within cognate regulatory regions of the IL2RA locus and characterized their methylation in naive, regulatory, and memory CD4+ T cells. We found that 5/18 CpGs (notably CpG + 3502) show dynamic, active demethylation during the in vitro activation of naive CD4+ T cells. Demethylation of these CpGs correlates with appearance of IL2RA protein at the cell surface. We found no influence of cis located SNP alleles upon CpG methylation. Treg cells show constitutive demethylation at all studied CpGs. Methylation of 9/18 CpGs, including CpG +3502, decreases with age. Our data thus identify CpG +3502 and a few other CpGs at the IL2RA locus as coordinated epigenetic regulators of IL2RA expression in CD4+ T cells. This may contribute to unravel how the IL2RA locus can be involved in immune physiology and pathology.

VDR Gene Haplotypes Associate with Type 1 Diabetes and Suggest Interaction with HLA, IL2RA and CTLA4 loci in Colombian Families

Vitamin D and its receptor are possibly related to T-cell-mediated autoimmune diseases and influences susceptibility to Type 1 diabetes (T1D). The aim of this study was to assess the contribution of vitamin D receptor (VDR) polymorphisms to the susceptibility to T1D in a Colombian sample. Associations of VDR gene variants with T1D were investigated in a sample of 200 familial trios from Colombia. VDR polymorphisms FokI (rs2228570), BsmI (rs1544410), ApaI (rs7975232) and TaqI (rs731236), were determined using PCR-RFLP methodology.

P095 Consequences of an IL2RA locus duplication in a very early onset inflammatory bowel disease patient

P095 Consequences of an IL2RA locus duplication in a very early onset inflammatory bowel disease patient

Two separate effects contribute to regulatory T cell defect in systemic lupus erythematosus patients and their unaffected relatives.

SummaryForkhead box P3 (FoxP3)+ regulatory T cells (Tregs) are functionally deficient in systemic lupus erythematosus (SLE), characterized by reduced surface CD25 [the interleukin (IL)‐2 receptor alpha chain]. Low‐dose IL‐2 therapy is a promising current approach to correct this defect. To elucidate the origins of the SLE Treg phenotype, we studied its role through developmentally defined regulatory T cell (Treg) subsets in 45 SLE patients, 103 SLE‐unaffected first‐degree relatives and 61 unrelated healthy control subjects, and genetic association with the CD25‐encoding IL2RA locus. We identified two separate, uncorrelated effects contributing to Treg CD25. (1) SLE patients and unaffected relatives remarkably shared CD25 reduction versus controls, particularly in the developmentally earliest CD4+FoxP3+CD45RO–CD31+ recent thymic emigrant Tregs. This first component effect influenced the proportions of circulating CD4+FoxP3highCD45RO+ activated Tregs. (2) In contrast, patients and unaffected relatives differed sharply in their activated Treg CD25 state: while relatives as control subjects up‐regulated CD25 strongly in these cells during differentiation from naive Tregs, SLE patients specifically failed to do so. This CD25 up‐regulation depended upon IL2RA genetic variation and was related functionally to the proliferation of activated Tregs, but not to their circulating numbers. Both effects were found related to T cell IL‐2 production. Our results point to (1) a heritable, intrathymic mechanism responsible for reduced CD25 on early Tregs and decreased activation capacity in an extended risk population, which can be compensated by (2) functionally independent CD25 up‐regulation upon peripheral Treg activation that is selectively deficient in patients. We expect that Treg‐directed therapies can be monitored more effectively when taking this distinction into account.

Multiple single nucleotide polymorphisms in the first intron of the IL2RA gene affect transcription factor binding and enhancer activity

IL2RA gene encodes the alpha subunit of a high-affinity receptor for interleukin-2 which is expressed by several distinct populations of lymphocytes involved in autoimmune processes. A large number of polymorphic alleles of the IL2RA locus are associated with the development of various autoimmune diseases. With bioinformatics analysis we the dissected the first intron of the IL2RA gene and selected several single nucleotide polymorphisms (SNPs) that may influence the regulation of the IL2RA gene in cell types relevant to autoimmune pathology. We described five enhancers containing the selected SNPs that stimulated activity of the IL2RA promoter in a cell-type specific manner, and tested the effect of specific SNP alleles on activity of the respective enhancers (E1 to E5, labeled according to the distance to the promoter). The E4 enhancer with minor T variant of rs61839660 SNP demonstrated reduced activity due to disrupted binding of MEF2A/C transcription factors (TFs). Neither rs706778 nor rs706779 SNPs, both associated with a number of autoimmune diseases, had any effect on the activity of the enhancer E2. However, rare variants of several SNPs (rs139767239, rs115133228, rs12722502, rs12722635) genetically linked to either rs706778 and/or rs706779 significantly influenced the activity of E1, E3 and E5 enhancers, presumably by disrupting EBF1, GABPA and ELF1 binding sites.

Associations of Independent IL2RA Gene Variants with Intermediate Uveitis

PurposeThe genetic background for the concomitance of uveitis and other autoimmune diseases remains elusive. Here the role of two IL2RA gene variants (rs11594656 and rs12722495) was investigated in intermediate uveitis and HLAB27 acute anterior uveitis.Materials and MethodsOne hundred fifty-nine patients with HLAB27 acute anterior uveitis, 85 patients with intermediate uveitis, 138 HLAB27 negative controls and 100 HLAB27 positive controls were recruited for this case-control study. Main outcome measures were genotype distribution and allelic frequencies determined by polymerase chain reaction.ResultsThe frequencies of carriers of the minor allele at rs11594656 and rs12722495 were significantly different in patients with intermediate uveitis compared to HLAB27 positive and negative controls combined (p<0.05). For rs12722495 the minor G allele was protective (genotypic OR: 0.29 [0.12-0.69]), and for rs11594656 the minor A allele conferred risk (genotypic OR: 1.59 [1.09-2.32]). No significant differences in genotype distribution were found between patients with HLAB27 acute anterior uveitis and HLAB27 positive or negative control subjects.ConclusionsWe found rs11594656 and rs12722495 to be associated with intermediate uveitis but not with HLAB27 acute anterior uveitis. The genetic heterogeneity found at the IL2RA locus could help explain patterns of concomitance with other autoimmune diseases.

IL2RA (CD25) Recruits Inhibitory Phosphatases to the Cell Membrane and Mediates Negative Feedback Control of STAT5 Signaling in Acute Lymphoblastic Leukemia

▪Background and hypothesis: CD25 (IL2RA, interleukin 2 receptor α chain) is a transmembrane protein with a 13aa cytoplasmic tail. CD25 cooperates with β- and γ-chains in binding IL-2, but does not contribute to cytokine signaling. During normal B cell development, CD25 is specifically upregulated on the surface of IL7-dependent pre-B cells and is also expressed on the surface of a subset of human pre-B ALL cases. CD25-expressing ALL is typically associated with poor clinical outcome. For these reasons, we studied the functional significance of CD25 expression on human pre-B ALL cells.Results: Flow cytometry and immunohistochemistry staining on a large panel of patient samples (n=416; MDACC, ECOG) revealed specific cell surface expression of CD25 in Ph+ ALL and Ph-like ALL, which are both high-risk subtypes of ALL. In agreement with selective expression on high-risk subsets, high expression levels of CD25 at the time of diagnosis were predictive of poor overall clinical outcome in these studies (P=0.005). BCR-ABL1 in Ph+ ALL and related tyrosine kinases in Ph-like ALL strongly activate STAT5, which then induces transcriptional activation of the IL2RA locus. Since Stat5 is also active during normal pre-B cell differentiation, we first analyzed B cell development in Il2ra-/- mouse bone marrow. Il2ra-/- B cell development was blocked at the pre-B cell stage, consistent with specific upregulation of CD25 on pre-B cells. In human Ph+ ALL cells, we found IL2RB and IL2RG were not co-expressed with CD25, suggesting a function of CD25 in Ph+ALL that is distinct from IL2 signaling. To test the biological significance of tyrosine kinase/STAT5-induced activation of CD25, we developed an Il2ra-/- mouse model for BCR-ABL1 pre-B ALL. Interestingly, the cytoplasmic tail of CD25 includes phosphorylation sites (S268 and T271) that are known substrates for serine/threonine phosphorylation by PKCα, which was reported to regulate protein phosphatase 2A (PP2A). To investigate interacting proteins with the cytoplasmic tail of CD25, we performed immune precipitation (IP) against the flag-tagged CD25-tail in primary Ph+ ALL cells which were transduced with either a CD25-tail-flag or an EV-flag vector. 2D mass spectrometry and Western blot on the IP products confirmed strong interactions with PKCα and PP2A. Weestern blot analysis confirmed additional interactions with inhibitory phosphatases including PTEN, PTPN6 (SHP1) and Inpp5d (SHIP1) in human Ph+ALL cells. In addition, both 2D MS and Westernblot showed recruitment of the Stat5-feedback inhibitors CISH, SOCS2 and SOCS3 at the CD25 cytoplasmic tail.Studying functional parameters of Il2ra-/-BCR-ABL1 ALL cells, we found impaired proliferation and colony formation capacity and drastically increased increased phosphorylation levels of pABLY412, pSTAT5Y694, pERKT202/Y204, pAKTS473, pP38T180/Y182 and p53. Reconstitution of CD25 expression restored normal phosphorylation levels of these molecules, as well as proliferation and colony formation.In a serial transplant setting, we observed that leukemia initiation in transplant recipients from Il2ra-/-BCR-ABL1 ALL cells required 10- to 100-times higher cell numbers, suggesting that CD25 contributes to leukemia initiation. In addition, CD25 expression is associated with a higher level of drug-resistance: In patient-derived pre-B ALL cells with mixed CD25Low and CD25High populations, the standard chemotherapy agent vincristine selectively induced apoptosis of in CD25Low but not CD25High ALL cells. An anti-CD25 immunotoxin drugs efficiently eradiated CD25High leukemia cells and thereby overcame drug-resistance against vincristine.Conclusions: Our studies identified CD25 as a surface receptor that mediates membrane recruitment of PP2A and CISH, SOCS2, negative feedback regulators of STAT5. CD25 is transcriptionally activated by STAT5 and therefore specifically expressed on high-risk ALL subtypes with oncogenic activation of the Stat5 pathway (Ph+ ALL and Ph-like ALL). We propose that CD25-mediated negative feedback control stabilizes oncogenic tyrosine kinase signaling and mediates drug-resistance in Ph+ ALL and Ph-like ALL cells. Targeted inhibition using CD25-directed immunotoxins may be useful in new approaches to overcome drug-resistance in Ph+ ALL and Ph-like ALL. DisclosuresNo relevant conflicts of interest to declare.

A3.6 Two components contributing to reduced treg surface CD25 in sle patients and their unaffected relatives

BackgroundFOXP3+ regulatory T-cells (Tregs) in Systemic Lupus Erythematosus (SLE) are in a functionally deficient state with a characteristic reduction or absence of surface CD25 (the IL-2 receptor alpha chain). Genetic...

Multiple Autoimmune-Associated Variants Confer Decreased IL-2R Signaling in CD4+CD25hi T Cells of Type 1 Diabetic and Multiple Sclerosis Patients

IL-2 receptor (IL-2R) signaling is essential for optimal stability and function of CD4+CD25hiFOXP3+ regulatory T cells (Treg); a cell type that plays an integral role in maintaining tolerance. Thus, we hypothesized that decreased response to IL-2 may be a common phenotype of subjects who have autoimmune diseases associated with variants in the IL2RA locus, including T1D and MS, particularly in cells expressing the high affinity IL-2R alpha chain (IL-2RA or CD25). To examine this question we used phosphorylation of STAT5 (pSTAT5) as a downstream measure of IL-2R signaling, and found a decreased response to IL-2 in CD4+CD25hi T cells of T1D and MS, but not SLE patients. Since the IL2RArs2104286 haplotype is associated with T1D and MS, we measured pSTAT5 in controls carrying the rs2104286 risk haplotype to test whether this variant contributed to reduced IL-2 responsiveness. Consistent with this, we found decreased pSTAT5 in subjects carrying the rs2104286 risk haplotype. Reduced IL-2R signaling did not result from lower CD25 expression on CD25hi cells; instead we detected increased CD25 expression on naive Treg from controls carrying the rs2104286 risk haplotype, and subjects with T1D and MS. However the rs2104286 risk haplotype correlated with increased soluble IL-2RA levels, suggesting that shedding of the IL-2R may account in part for the reduced IL-2R signaling associated with the rs2104286 risk haplotype. In addition to risk variants in IL2RA, we found that the T1D-associated risk variant of PTPN2rs1893217 independently contributed to diminished IL-2R signaling. However, even when holding genotype constant at IL2RA and PTPN2, we still observed a significant signaling defect in T1D and MS patients. Together, these data suggest that multiple mechanisms converge in disease leading to decreased response to IL-2, a phenotype that may eventually lead to loss of tolerance and autoimmunity.

Epigenetic Modifications Induced by Blimp-1 Regulate CD8+ T Cell Memory Progression during Acute Virus Infection

The transcription factor Blimp-1 regulates the overall accumulation of virus-specific CD8⁺ T cells during acute viral infections. We found that increased proliferation and survival of Blimp-1-deficient CD8⁺ T cells resulted from sustained expression of CD25 and CD27 and persistent cytokine responsiveness. Silencing of Il2ra and Cd27 reduced the Blimp-1-deficient CD8⁺ T cell response. Genome-wide chromatin immunoprecipitation (ChIP) sequencing analysis identified Il2ra and Cd27 as direct targets of Blimp-1. At the peak of the antiviral response, but not earlier, Blimp-1 recruited the histone-modifying enzymes G9a and HDAC2 to the Il2ra and Cd27 loci, thereby repressing expression of these genes. In the absence of Blimp-1, Il2ra and Cd27 exhibited enhanced histone H3 acetylation and reduced histone H3K9 trimethylation. These data elucidate a central mechanism by which Blimp-1 acts as an epigenetic regulator and enhances the numbers of short-lived effector cells while suppressing the development of memory-precursor CD8⁺ T cells.

Association of Variants in IL2RA With Progression of Joint Destruction in Rheumatoid Arthritis

Heritability studies have suggested an important role of genetic predisposition in the progression of joint destruction in rheumatoid arthritis (RA); the heritability is estimated at 45-58%. Several single-nucleotide polymorphisms (SNPs) have been identified as being associated with RA susceptibility. Our objective was to study the association of several of these loci with progression of joint destruction. We studied 1,750 RA patients in 4 independent data sets with 4,732 radiographs scored using the modified Sharp/van der Heijde method. Thirteen susceptibility SNPs that were not previously associated with joint destruction were tested in 596 Dutch RA patients. Subsequently, significant SNPs were studied in data sets of RA patients from North America and Iceland. Data were summarized in inverse-weighted variance meta-analyses. Further, the association with circulating protein levels was studied and the associated region was fine-mapped. In stage 1, 3 loci (AFF3, IL2RA, and BLK) were significantly associated with the rate of joint destruction and were further analyzed in the additional data sets. In the combined meta-analyses, the minor (C) allele of IL2RA (rs2104286) was associated with less progression of joint destruction (P = 7.2 × 10(-4) ). Furthermore, the IL2RA (rs2104286) protective genotype was associated with lower (0.85-fold [95% confidence interval 0.77-0.93], P = 1.4 × 10(-3) ) circulating levels of soluble interleukin-2 receptor α (sIL-2Rα). Additionally, lower sIL-2Rα levels were associated with a lower rate of joint destruction (P = 3.4 × 10(-3) ). The association of IL2RA with the rate of joint destruction was further localized to a 40-kb region encompassing the IL2RA intron 1 and the 5' region of IL2RA and RBM17. The present genetic and serologic data suggest that inherited altered genetic constitution at the IL2RA locus may predispose to a less destructive course of RA.

Evaluation of the IL2/IL21, IL2RA and IL2RB genetic variants influence on the endogenous non-anterior uveitis genetic predisposition

BackgroundRecently, different genetic variants located within the IL2/IL21 genetic region as well as within both IL2RA and IL2RB loci have been associated to multiple autoimmune disorders. We aimed to investigate for the first time the potential influence of the IL2/IL21, IL2RA and IL2RB most associated polymorphisms with autoimmunity on the endogenous non-anterior uveitis genetic predisposition.MethodsA total of 196 patients with endogenous non-anterior uveitis and 760 healthy controls, all of them from Caucasian population, were included in the current study. The IL2/IL21 (rs2069762, rs6822844 and rs907715), IL2RA (2104286, rs11594656 and rs12722495) and IL2RB (rs743777) genetic variants were genotyped using TaqMan® allelic discrimination assays.ResultsA statistically significant difference was found for the rs6822844 (IL2/IL21 region) minor allele frequency in the group of uveitis patients compared with controls (P-value=0.02, OR=0.64 CI 95%=0.43-0.94) although the significance was lost after multiple testing correction. Furthermore, no evidence of association with uveitis was detected for the analyzed genetic variants of the IL2RA or IL2RB loci.ConclusionOur results indicate that analyzed IL2/IL21, IL2RA and IL2RB polymorphisms do not seem to play a significant role on the non-anterior uveitis genetic predisposition although further studies are needed in order to clear up the influence of these loci on the non-anterior uveitis susceptibility.

Dense mapping of IL2RA shows no association with Graves' disease in Chinese Han population

Associations between IL2RA and various autoimmune diseases have been reported in Caucasians. We investigated whether genetic polymorphisms at the IL2RA locus were associated with Graves' disease (GD) in the Chinese Han population. We performed a genome-wide association study (GWAS) in 1 536 GD patients and 1 516 controls. The 1000 Genomes Project data were adopted as references for imputation analysis. After forward and conditional logistic regressions, we found that rs11256313 was the major risk variant in the CD25/IL2RA region. Thus, we further genotyped rs11256313 in a replication cohort with 3 694 GD patients and 3 510 controls using ABI 7900HT TaqMan Real-Time PCR System. Nine single nucleotide polymorphisms (SNPs) in the IL2RA block were nominally associated with GD in our GWAS (0·01 < P < 0·05). After imputation analysis, 13 imputed SNPs in the IL2RA block were weakly associated with GD (P ≤ 0·05). Logistic regression analysis suggested that the imputed rs11256313 could represent the IL2RA block (P = 0·003). However, we failed to replicate the association of rs11256313 in a larger cohort (P = 0·145). A subphenotype analysis of rs11256313 on thyroid hormone receptor antibody (TRAb) and gender showed that there was no association in any of the subphenotype groups (P > 0·05). The results suggested that common genetic polymorphisms at IL2RA do not exert a significant genetic effect on the development of GD in the Chinese Han population. Previously reported associations between CD25/IL2RA and autoimmune diseases including GD in Caucasians again imply that heterogeneity exists in different ethnic populations.

Proteome-Wide Analysis of Disease-Associated SNPs That Show Allele-Specific Transcription Factor Binding

A causative role for single nucleotide polymorphisms (SNPs) in many genetic disorders has become evident through numerous genome-wide association studies. However, identification of these common causal variants and the molecular mechanisms underlying these associations remains a major challenge. Differential transcription factor binding at a SNP resulting in altered gene expression is one possible mechanism. Here we apply PWAS (“proteome-wide analysis of SNPs”), a methodology based on quantitative mass spectrometry that enables rapid screening of SNPs for differential transcription factor binding, to 12 SNPs that are highly associated with type 1 diabetes at the IL2RA locus, encoding the interleukin-2 receptor CD25. We report differential, allele-specific binding of the transcription factors RUNX1, LEF1, CREB, and TFAP4 to IL2RA SNPs rs12722508*A, rs12722522*C, rs41295061*A, and rs2104286*A and demonstrate the functional influence of RUNX1 at rs12722508 by reporter gene assay. Thus, PWAS may be able to contribute to our understanding of the molecular consequences of human genetic variability underpinning susceptibility to multi-factorial disease.