Vitamin D status and pathway genes in five European autoimmune Addison's disease cohorts.

OBJECTIVE: While vitamin D regulates immune cells, little is known about it in autoimmune Addison's disease (AAD). We investigated the vitamin D status in AAD patients from five European populations to assess its deficiency. In addition, we studied two case-control cohorts for vitamin D metabolism and pathway genes. DESIGN: Cross-sectional study. METHODS: A total of 1028 patients with AAD from Germany (n = 239), Italy (n = 328), Norway (n = 378), UK (n = 44) and Poland (n = 39) and 679 controls from Germany (n = 301) and Norway (n = 378) were studied for 25(OH)D3 (primary objective). Secondary objectives (1,25(OH)2D3 and pathway genes) were examined in case-controls from Germany and Norway correlating 25(OH)D3 and single nucleotide polymorphisms within genes encoding the vitamin D receptor (VDR), 1-α-hydroxylase (CYP27B1), 25-hydroxylase (CYP2R1), 24-hydroxylase (CYP24A1) and vitamin D binding protein (GC/DBP). RESULTS: Vitamin D deficiency (25(OH)D3 10-20 ng/mL) was highly prevalent in AAD patients (34-57%), 5-22% were severely deficient (<10 ng/mL), 28-38% insufficient (20-30 ng/mL) and only 7-14% sufficient (>30 ng/mL). Lower 25(OH)D3 and 1,25(OH)2D3 levels were observed both in Norwegian and German AAD (P = 0.03/0.003 and P = 1 × 10-5/< 1 × 10-7, respectively) the former was associated with CYP2R1 (rs1553006) genotype G. Whereas controls achieved sufficient median 25(OH)D3 in summers (21.4 to 21.9 ng/mL), AAD patients remained largely deficient (18.0 to 21.2 ng/mL) and synthesize less 1,25(OH)2D3. CONCLUSION: Vitamin D deficiency and insufficiency are highly prevalent in AAD patients. The vitamin D status of AAD may be influenced by genetic factors and suggests individual vitamin D requirements throughout the year.

Coexistence of Congenital Adrenal Hyperplasia and Autoimmune Addison's Disease.

Background: Underlying causes of adrenal insufficiency include congenital adrenal hyperplasia (CAH) and autoimmune adrenocortical destruction leading to autoimmune Addison's disease (AAD). Here, we report a patient with a homozygous stop-gain mutation in 3ß-hydroxysteroid dehydrogenase type 2 (3ßHSD2), in addition to impaired steroidogenesis due to AAD. Case Report: Whole exome sequencing revealed an extremely rare homozygous nonsense mutation in exon 2 of the HSD3B2 gene, leading to a premature stop codon (NM_000198.3: c.15C>A, p.Cys5Ter) in a patient with AAD and premature ovarian insufficiency. Scrutiny of old medical records revealed that the patient was initially diagnosed with CAH with hyperandrogenism and severe salt-wasting shortly after birth. However, the current steroid profile show complete adrenal insufficiency including low production of pregnenolone, dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEA-S), without signs of overtreatment with steroids. Conclusion: To the best of our knowledge, this is the first description of autoimmune adrenalitis in a patient with 3ßHSD2 deficiency and suggests a possible association between AAD and inborn errors of the steroidogenesis.

Identification and characterization of rare toll-like receptor 3 variants in patients with autoimmune Addison's disease.

Autoimmune Addison's disease (AAD) is a classic organ-specific autoimmune disease characterized by an immune-mediated attack on the adrenal cortex. As most autoimmune diseases, AAD is believed to be caused by a combination of genetic and environmental factors, and probably interactions between the two. Persistent viral infections have been suggested to play a triggering role, by invoking inflammation and autoimmune destruction. The inability of clearing infections can be due to aberrations in innate immunity, including mutations in genes involved in the recognition of conserved microbial patterns. In a whole exome sequencing study of anonymized AAD patients, we discovered several rare variants predicted to be damaging in the gene encoding Toll-like receptor 3 (TLR3). TLR3 recognizes double stranded RNAs, and is therefore a major factor in antiviral defense. We here report the occurrence and functional characterization of five rare missense variants in TLR3 of patients with AAD. Most of these variants occurred together with a common TLR3 variant that has been associated with a wide range of immunopathologies. The biological implications of these variants on TLR3 function were evaluated in a cell-based assay, revealing a partial loss-of-function effect of three of the rare variants. In addition, rare mutations in other members of the TLR3-interferon (IFN) signaling pathway were detected in the AAD patients. Together, these findings indicate a potential role for TLR3 and downstream signaling proteins in the pathogenesis in a subset of AAD patients.

CYP21A2 polymorphisms in patients with autoimmune Addison's disease, and linkage disequilibrium to HLA risk alleles.

OBJECTIVE: Steroid 21-hydroxylase, encoded by CYP21A2, is the major autoantigen in autoimmune Addison's disease (AAD). CYP21A2 is located in the region of the HLA complex on chromosome 6p21.3, which harbours several risk alleles for AAD. The objective was to investigate whether CYP21A2 gene variants confer risk of AAD independently of other risk alleles in the HLA loci. DESIGN: DNA samples from 381 Norwegian patients with AAD and 340 healthy controls (HC) previously genotyped for the HLA-A, -B, -DRB1, and -DQB1 and MICA loci were used for genotyping of CYP21A2. METHODS: Genotyping of CYP21A2 was carried out by direct sequencing. Linkage of CYP21A2 to the HLA loci was assessed using UNPHASED version 3.0.10 and PHASE version 2.1. RESULTS: Heterozygotes of the single-nucleotide polymorphisms (SNPs) rs397515394, rs6467, rs6474, rs76565726 and rs6473 were detected significantly more frequently in AAD patients compared with HC (P<0.005), but all SNPs were in a linkage disequilibrium (LD) with high-risk HLA-DRB1 haplotypes. rs6472C protected against AAD (odds ratio=0.15, 95% CI (0.08-0.30), P=3.8×10(-10)). This SNP was not in an LD with HLA loci (P=0.02), but did not increase protection when considering the effect of HLA-DRB1 alleles. Mutations causing congenital adrenal hyperplasia were found in heterozygosity in <1.5% of the cases in both groups. CONCLUSION: Genetic variants of CYP21A2 associated to AAD are in LD with the main AAD risk locus HLA-DRB1, and CYP21A2 does not constitute an independent susceptibility locus.

Association of autoimmune Addison's disease with alleles of STAT4 and GATA3 in European cohorts.

BACKGROUND: Gene variants known to contribute to Autoimmune Addison's disease (AAD) susceptibility include those at the MHC, MICA, CIITA, CTLA4, PTPN22, CYP27B1, NLRP-1 and CD274 loci. The majority of the genetic component to disease susceptibility has yet to be accounted for. AIM: To investigate the role of 19 candidate genes in AAD susceptibility in six European case-control cohorts. METHODS: A sequential association study design was employed with genotyping using Sequenom iPlex technology. In phase one, 85 SNPs in 19 genes were genotyped in UK and Norwegian AAD cohorts (691 AAD, 715 controls). In phase two, 21 SNPs in 11 genes were genotyped in German, Swedish, Italian and Polish cohorts (1264 AAD, 1221 controls). In phase three, to explore association of GATA3 polymorphisms with AAD and to determine if this association extended to other autoimmune conditions, 15 SNPs in GATA3 were studied in UK and Norwegian AAD cohorts, 1195 type 1 diabetes patients from Norway, 650 rheumatoid arthritis patients from New Zealand and in 283 UK Graves' disease patients. Meta-analysis was used to compare genotype frequencies between the participating centres, allowing for heterogeneity. RESULTS: We report significant association with alleles of two STAT4 markers in AAD cohorts (rs4274624: P = 0.00016; rs10931481: P = 0.0007). In addition, nominal association of AAD with alleles at GATA3 was found in 3 patient cohorts and supported by meta-analysis. Association of AAD with CYP27B1 alleles was also confirmed, which replicates previous published data. Finally, nominal association was found at SNPs in both the NF-κB1 and IL23A genes in the UK and Italian cohorts respectively. CONCLUSIONS: Variants in the STAT4 gene, previously associated with other autoimmune conditions, confer susceptibility to AAD. Additionally, we report association of GATA3 variants with AAD: this adds to the recent report of association of GATA3 variants with rheumatoid arthritis.

Interaction analysis between HLA-DRB1 shared epitope alleles and MHC class II transactivator CIITA gene with regard to risk of rheumatoid arthritis.

HLA-DRB1 shared epitope (SE) alleles are the strongest genetic determinants for autoantibody positive rheumatoid arthritis (RA). One of the key regulators in expression of HLA class II receptors is MHC class II transactivator (CIITA). A variant of the CIITA gene has been found to associate with inflammatory diseases.We wanted to explore whether the risk variant rs3087456 in the CIITA gene interacts with the HLA-DRB1 SE alleles regarding the risk of developing RA. We tested this hypothesis in a case-control study with 11767 individuals from four European Caucasian populations (6649 RA cases and 5118 controls).We found no significant additive interaction for risk alleles among Swedish Caucasians with RA (n = 3869, attributable proportion due to interaction (AP) = 0.2, 95%CI: -0.2-0.5) or when stratifying for anti-citrullinated protein antibodies (ACPA) presence (ACPA positive disease: n = 2945, AP = 0.3, 95%CI: -0.05-0.6, ACPA negative: n = 2268, AP = -0.2, 95%CI: -1.0-0.6). We further found no significant interaction between the main subgroups of SE alleles (DRB1*01, DRB1*04 or DRB1*10) and CIITA. Similar analysis of three independent RA cohorts from British, Dutch and Norwegian populations also indicated an absence of significant interaction between genetic variants in CIITA and SE alleles with regard to RA risk.Our data suggest that risk from the CIITA locus is independent of the major risk for RA from HLA-DRB1 SE alleles, given that no significant interaction between rs3087456 and SE alleles was observed. Since a biological link between products of these genes is evident, the genetic contribution from CIITA and class II antigens in the autoimmune process may involve additional unidentified factors.

Multiple loci in the HLA complex are associated with Addison's disease.

CONTEXT: A strong association between autoimmune Addison's disease (AAD) and major histocompatibility complex class II-encoded HLA-DRB1-DQA1-DQB1 haplotypes is well known. Recent evidence from other autoimmune diseases has suggested that class I-encoded HLA-A and HLA-B gene variants confer HLA-DRB1-DQA1-DQB1-independent effects on disease. OBJECTIVE: We aimed to explore AAD predisposing effects of HLA-A and -B and further investigate the role of MICA and HLA-DRB1-DQA1-DQB1 in a much larger material than has previously been studied. DESIGN: HLA-A, -B, -DRB1, and -DQB1 and a microsatellite in MICA were genotyped in 414 AAD patients and 684 controls of Norwegian origin. RESULTS: The strongest association was observed for the DRB1 locus, in which the DRB1*03:01 and DRB1*04:04 conferred increased risk of AAD, particularly in a heterozygous combination [odds ratio 22.13; 95% confidence interval (11.39-43.98); P = 6 × 10(-20)]. After conditioning on DRB1, association with AAD was still present for HLA-B and MICA, suggesting the presence of additional risk factors. CONCLUSIONS: The major histocompatibility complex harbors multiple risk loci for AAD, in which DRB1 appears to represent the main risk factor.

A CLEC16A variant confers risk for juvenile idiopathic arthritis and anti-cyclic citrullinated peptide antibody negative rheumatoid arthritis.

OBJECTIVE: Variants in CLEC16A have conferred susceptibility to autoimmune diseases in genome-wide association studies. The present work aimed to investigate the locus' involvements in juvenile idiopathic arthritis (JIA) and further explore the association with rheumatoid arthritis (RA), type 1 diabetes (T1D) and Addison's disease (AD) in the Norwegian population. METHODS: Three single nucleotide polymorphisms (SNPs) were genotyped in patients with RA (n=809), JIA (n=509), T1D (n=1211) and AD (n=414) and in healthy controls (n=2149). RESULTS: All diseases were associated with CLEC16A, but with different SNPs. The intron 22 SNP, rs6498169, was associated with RA (p=0.006) and JIA (p=0.016) and the intron 19 SNPs, rs12708716/rs12917716, with T1D (p=1x10-5) and AD (p=2x10-4). The RA association was confined to the anti-cyclic citrullinated peptide antibody (anti-CCP) negative subgroup (p=2x10-4). CONCLUSION: This is the first report of a CLEC16A association with JIA and a split of the RA association according to anti-CCP status. Different causative variants underlie the rheumatic versus the organ specific diseases.

T cell responses to steroid cytochrome P450 21-hydroxylase in patients with autoimmune primary adrenal insufficiency.

CONTEXT: Autoimmune Addison's disease is thought to result from T cell mediated autoimmunity. Autoantibodies against the steroidogenic cytochrome P450 enzyme 21-hydroxylase (21OH) are found in most patients, and 21OH is therefore a likely target for antigen-specific T cells. OBJECTIVE: The aim was to study cellular immunity to 21OH and its associations with 21OH autoantibodies and human leukocyte antigen alleles in autoimmune Addison's disease. DESIGN/PATIENTS: Peripheral blood mononuclear cells were collected from 33 patients with autoimmune Addison's disease and 21 controls. Cellular proliferation and production of cytokines in response to stimulation with 21OH or 21OH-derived peptides were tested. RESULTS: Cellular proliferation (P = 0.0009) and secretion of interferon-gamma (P < 0.0001) in response to 21OH was significantly higher in patients compared to healthy controls and associated with the presence of 21OH autoantibodies (P = 0.0052). Furthermore, the 21OH-specific production of interferon-gamma was enhanced in the presence of 21OH autoantibodies. This effect was partially inhibited by antibodies against the Fc receptor for IgG, CD32. Moreover, mature dendritic cells proved superior to the other antigen-presenting cells in invoking cellular responses to 21OH. An association between cellular immunity to 21OH and the high-risk HLA genotype for Addison's disease, DRB1*0301-DQ2/DRB1*0404-DQ8, was observed (P = 0.0089). Finally, a significant association between the DRB1*0404-DQ8 haplotype and cellular responses to a 21OH-derived peptide predicted to bind to DRB1*0404 was detected (P = 0.0055). CONCLUSION: Patients with autoimmune Addison's disease have circulating 21OH-specific T cells, with amino acids 342-361 of 21OH possibly constituting a disease-specific epitope presented by HLA-DRB1*0404.

Programmed death ligand 1 (PD-L1) gene variants contribute to autoimmune Addison's disease and Graves' disease susceptibility.

CONTEXT: Despite much investigation, a substantial amount of the genetic susceptibility to autoimmune diseases remains unaccounted for. Recently, a single-nucleotide polymorphism (SNP) in the programmed death ligand 1 (PD-L1) gene has been associated with Graves' disease (GD) in a Japanese patient cohort. Our aim was to determine whether variants in PD-L1 are also associated with autoimmune Addison's disease (AAD) and to replicate the previous association in patients with GD from the United Kingdom. DESIGN AND PATIENTS: We analyzed eight SNPs within PD-L1 in a United Kingdom cohort of 315 AAD subjects and 316 healthy controls. We then replicated our experiment in a cohort of 342 Norwegian AAD cases and 379 controls and in 496 United Kingdom GD subjects. RESULTS: Three of the eight SNPs studied, part of a haplotype block in the PD-L1 gene, showed modest association with both AAD and GD in the United Kingdom cohort, with maximum evidence at the marker RS1411262 [United Kingdom AAD odds ratio 1.33 (5-95% confidence interval 1.02-1.73), P(genotype) = 0.028; GD odds ratio 1.36 (5-95% confidence interval 1.07-1.72), P(genotype) = 0.033]. Association with genotypes at the same three markers was confirmed in the Norwegian AAD cohort [P(genotype) = 0.011-0.020]. A recessive effect at the most associated alleles was observed in both the AAD and GD cohorts. CONCLUSIONS: We confirm the role of PD-L1 variants in GD susceptibility and extend these findings to demonstrate association in two Northern European patient cohorts with AAD. PD-L1 joins the growing number of known susceptibility loci exerting modest effects in these autoimmune disorders.

Clinical, immunological, and genetic features of autoimmune primary adrenal insufficiency: observations from a Norwegian registry.

OBJECTIVE: Primary adrenal insufficiency [Addison's disease (AD)] is rare, and systematic studies are few, mostly conducted on small patient samples. We aimed to determine the clinical, immunological, and genetic features of a national registry-based cohort. DESIGN: Patients with AD identified through a nationwide search of diagnosis registries were invited to participate in a survey of clinical features, health-related quality of life (HRQoL), autoantibody assays, and human leukocyte antigen (HLA) class II typing. RESULTS: Of 664 registered patients, 64% participated in the study. The prevalence of autoimmune or idiopathic AD in Norway was 144 per million, and the incidence was 0.44 per 100,000 per year (1993-2007). Familial disease was reported by 10% and autoimmune comorbidity by 66%. Thyroid disease was most common (47%), followed by type 1 diabetes (12%), vitiligo (11%), vitamin B12 deficiency (10%), and premature ovarian insufficiency (6.6% of women). The mean daily treatment for AD was 40.5 mg cortisone acetate and 0.1 mg fludrocortisone. The mean Short Form 36 vitality scores were significantly diminished from the norm (51 vs. 60), especially among those with diabetes. Concomitant thyroid autoimmunity did not lower scores. Anti-21-hydroxylase antibodies were found in 86%. Particularly strong susceptibility for AD was found for the DR3-DQ2/ DRB1*0404-DQ8 genotype (odds ratio, 32; P = 4 x 10(-17)), which predicted early onset. CONCLUSIONS: AD is almost exclusively autoimmune, with high autoimmune comorbidity. Both anti-21-hydroxylase antibodies and HLA class II can be clinically relevant predictors of AD. HRQoL is reduced, especially among diabetes patients, whereas thyroid disease did not have an impact on HRQoL. Treatment modalities that improve HRQoL are needed.

X-linked congenital adrenal hypoplasia with hypogonadotropic hypogonadism caused by an inversion disrupting a conserved noncoding element upstream of the NR0B1 (DAX1) gene.

CONTEXT: X-linked congenital adrenal hypoplasia with hypogonadotropic hypogonadism (AHCH) is known to be caused by coding mutations in the nuclear receptor subfamily 0, group B, member 1 (NR0B1) gene, encoding the transcriptional repressor dosage-sensitive sex-reversal adrenal hypoplasia critical region on the X chromosome protein 1 (DAX1). OBJECTIVE/PATIENTS: Four males in a family were affected by AHCH. Our aim was to locate the genetic cause of their disease, knowing that they had no mutation in the obvious candidate gene, NR0B1. DESIGN: Linkage analysis of the X chromosome and mutational screening of conserved noncoding regions upstream of NR0B1 were performed. To functionally characterize the genetic defect, studies of transcription and expression of DAX1 and steroidogenic factor 1 (SF-1) were done. RESULTS: A 60 Mb inversion on the X chromosome with one of the inversion breakpoints located in a conserved noncoding region 4 kb upstream of NR0B1 was detected. The inversion causes relocation of a putative SF-1 binding site implicated in murine gonadal development. A reporter construct lacking this enhancer element upstream of NR0B1 was unresponsive to SF-1 transcriptional activation. Immunohistochemistry suggested that the inversion leads to SF-1 silencing in the patients' testes both in childhood and in adult life. CONCLUSION: We report a noncoding mutation causing AHCH, an inversion resulting in a phenotype similar to what is caused by intragenic NR0B1 null mutations. The inversion seems to disrupt and/or relocate regulatory sites crucial in DAX1 expression.

Polymorphisms in CLEC16A and CIITA at 16p13 are associated with primary adrenal insufficiency.

CONTEXT/OBJECTIVES: It is known that different autoimmune diseases often share the same susceptibility genes. In this study we aimed to investigate if loci found associated with common autoimmune diseases in recent genome-wide association studies also could be susceptibility loci for autoimmune Addison's disease (primary adrenal insufficiency). DESIGN/PATIENTS: A total of 139 tagging single nucleotide polymorphisms (SNPs) in 11 candidate genes (IL2, IL21, IL2RA, CLEC2D, CD69, ERBB3, PTPN11, SH2B3, CLEC16A, CIITA, and PTPN2) were genotyped in a case/control study design consisting of Norwegian Addison's disease patients (n = 332) and Norwegian healthy control individuals (n = 1029). Five SNPs were subsequently selected for analysis in a United Kingdom sample set consisting of Addison's disease patients (n = 210) and controls (n = 191). RESULTS: Polymorphisms in CLEC16A and CIITA remained significantly associated with Addison's disease in the Norwegian sample set at the 0.05 level, even after correction for multiple testing. CLEC16A and CIITA are both located at 16p13, but linkage disequilibrium patterns and logistical regression analyses suggest that SNPs in these two genes are independently associated with Addison's disease. We were not able to confirm these associations in the United Kingdom material, however, this may well be due to the limited sample size and lack of statistical power. CONCLUSION: Two alleles at 16p13 are independently associated with the risk of Addison's disease in the Norwegian population, suggesting this chromosomal region to harbor common autoimmunity gene(s), CLEC16A and CIITA being possible independent candidates.

Mutation screening of PTPN22: association of the 1858T-allele with Addison's disease.

The tyrosine-protein phosphatase non-receptor type 22 (PTPN22) gene was recently identified as an important genetic susceptibility factor in several autoimmune diseases. The increased risk has been broadly explained by the 1858T-allele (rs2476601). As two smaller studies on Addison's disease (AD) have shown diverging results, we aimed to elucidate the predisposing effect of the single-nucleotide polymorphism (SNP) 1858CT in a larger population of AD patients, especially focusing on the AD patients with known autoimmune etiology. We also screened for unknown rare or common variants in the PTPN22 gene that could predispose for AD. The case-control study of Norwegian AD patients (n=332) and controls (n=990) showed a significant association between autoimmune AD (n=302) and the PTPN22 1858T risk allele (P=0.016). The association of AD with 1858T was supported by a meta-analysis combining our genotype data with that of others published previously (P=0.003). The mutation screening of PTPN22 in AD patients (n=332) and controls (n=112) revealed eight missense variants, five of which have not been reported previously. In conclusion, the 1858T-allele is a PTPN22 genetic susceptibility factor for autoimmune AD. Other rare variants in PTPN22 do occur, and may also be involved in the pathogenesis.

FOXP3 polymorphisms in type 1 diabetes and coeliac disease.

The FOXP3 gene encodes a transcription factor thought to be essential for the development and function of T regulatory cells. Two previous studies have tested common polymorphisms in FOXP3 for association with type 1 diabetes (T1D) with conflicting results. The aim of our study was to see whether there is any evidence of association between the FOXP3 polymorphisms previously reported to be associated with T1D, in a Caucasian population regarding T1D and coeliac disease (CD). We further looked for evidence of interaction between FOXP3 polymorphisms and HLA-DR3 in conferring susceptibility to T1D. Initially, we analysed two microsatellites in the FOXP3 gene in 363 T1D nuclear families. Our results indicated an association between FOXP3 and T1D (global p=0.004) and a possible interaction between FOXP3 and the HLA-DR3-DQ2 susceptibility haplotype. We then genotyped an additional independent set of 826 T1D patients and 1459 controls as well as one CD dataset consisting of 325 families. A similar tendency was revealed in the CD family material (pnc=0.055 for the associated allele). On the other hand, we were unable to reproduce our initial findings in the T1D case-control dataset (global p=0.6). Our results suggest that the tested FOXP3 markers do not have any major impact on susceptibility for these diseases.

CFTR gene mutations and asthma in the Norwegian Environment and Childhood Asthma study.

BACKGROUND: Several candidate genes have been implicated in the etiology of asthma, including the gene coding for the cystic fibrosis transmembrane conductance regulator (CFTR). Mutations in the CFTR gene result in derangements of mucociliary clearance. Homozygotes for CFTR mutations develop cystic fibrosis (CF), a disorder characterized mainly by lung and pancreas disease. OBJECTIVE: To investigate whether there was an increased frequency of CFTR mutations in asthma patients. METHODS: Seven hundred and three subjects aged 10-11 years from the environment and childhood asthma (ECA) study were included in the present study. Possible associations between asthma, reduced lung function, bronchial hyperresponsiveness (BHR), and increased or decreased nitrogen oxide (NO) levels (based on structural parental interview, spirometry, PD20 methacholine challenge test and exhaled NO measurements), and the five most common CFTR mutations in Norway (DeltaF508, R117H, R117C, 4005+2T-->C, 394delTT), the modulating polymorphisms IVS8(TG)mTn and the IVS8-5T were investigated. RESULTS: No association were found between asthma, reduced lung function, BHR or exhaled NO levels and CF heterozygosity. However, the IVS8(TG)11T7 haplotype was associated with normal lung function. CONCLUSIONS: Our results do not support the hypothesis that CFTR mutations or polymorphisms play a role in the pathogenesis of asthma in children. However, the distribution of Tn(TG)m haplotypes differed between individuals with reduced lung function and individuals with normal lung function.

CTLA-4 polymorphisms in allergy and asthma and the TH1/ TH2 paradigm.

BACKGROUND: Several genomic regions are reported to be associated with the development of asthma and allergy, including chromosome 2q33. This region harbors the candidate gene cytotoxic T-lymphocyte antigen 4 (CTLA-4), an important regulator of T-cell activation and differentiation. OBJECTIVE: We sought to explore possible associations between CTLA-4 polymorphisms and allergy and asthma. METHODS: Seven single nucleotide polymorphisms (SNPs; MH30, -1147CT, +49AG, CT60, JO31, JO30, JO27_1) in CTLA-4 were analyzed for associations with total serum IgE, allergic sensitization (positive skin prick test to common allergens), bronchial hyperresponsiveness (BHR) to methacholine, asthma, and lung function (FEV1 % of predicted) in 364 asthmatic families from 3 European countries. RESULTS: Transmission disequilibrium test analysis showed that several SNPs were significantly associated with serum IgE levels, allergy, asthma, and FEV1 % predicted below 80%, but not with BHR, and CTLA-4 polymorphisms of potentially direct pathogenic significance in atopic disorders were identified. CONCLUSION: We identified associations between 4 newly discovered SNPs in the CTLA-4 gene and serum IgE levels, allergy, asthma, and reduced lung function, but not BHR, suggesting an important role for CTLA-4 in atopy and reduced lung function in asthmatic subjects rather than asthma per se. The particular SNP alleles found positively associated with our phenotypes were recently shown to be associated negatively with autoimmune disorders. Although a skewing toward a TH1 reactivity pattern is believed to characterize autoimmune diseases, atopic diseases are considered TH2-mediated. Hence, our data suggest a role for CTLA-4 polymorphisms in determining the TH1/TH2 balance and identify CTLA-4 signaling as a potential therapeutic target in atopic disease.