Polymorphisms in the cytotoxic T lymphocyte antigen-4 gene region confer susceptibility to Addison's disease

Successful treatment of nivolumab and ipilimumab triggered type 1 diabetes by using sodium-glucose transporter 2 inhibitor: a case report and systematic review

Objective

Checkpoint inhibitors (CPIs) can trigger complications related to the autoimmune process such as CPI-triggered diabetes mellitus. The typical treatment for CPI-triggered diabetes is insulin, but a detailed therapeutic method has not yet been established. To prevent severe symptoms and mortality of diabetic ketoacidosis in advanced-stage cancer patients, the establishment of effective treatment of CPI-triggered diabetes, other than insulin therapy, is required.

Methods

We present a case of a 76-year-old man with CPI-triggered diabetes who was treated with nivolumab and ipilimumab for lung cancer. We also conducted a systematic review of 48 case reports of type 1 diabetes associated with nivolumab and ipilimumab therapy before June 2023.

Results

The patient's hyperglycemia was not sufficiently controlled by insulin therapy, and after the remission of ketoacidosis, the addition of a sodium-glucose transporter (SGLT) 2 inhibitor, dapagliflozin, improved glycemic control. Most of the reported nivolumab/ipilimumab-induced type 1 diabetes was treatable with insulin, but very few cases required additional oral anti-diabetic agents to obtain good glucose control.

Conclusion

Although SGLT2 inhibitors have been reported to have adverse effects on ketoacidosis, recent studies indicate that the occurrence of ketoacidosis is relatively rare. Considering the pathological mechanism of CPI-triggered diabetes, SGLT2 inhibitors could be an effective choice if they are administered while carefully monitoring the patient's ketoacidosis.

The genetics of autoimmune Addison disease: past, present and future

Autoimmune Addison disease is an endocrinopathy that is fatal if not diagnosed and treated in a timely manner. Its rarity has hampered unbiased studies of the predisposing genetic factors. A 2021 genome-wide association study, explaining up to 40% of the genetic susceptibility, has revealed new disease loci and reproduced some of the previously reported associations, while failing to reproduce others. Credible risk loci from both candidate gene and genome-wide studies indicate that, like one of its most common comorbidities, type 1 diabetes mellitus, Addison disease is primarily caused by aberrant T cell behaviour. Here, we review the current understanding of the genetics of autoimmune Addison disease and its position in the wider field of autoimmune disorders. The mechanisms that could underlie the effects on the adrenal cortex are also discussed.

GWAS for autoimmune Addison's disease identifies multiple risk loci and highlights AIRE in disease susceptibility

Autoimmune Addison's disease (AAD) is characterized by the autoimmune destruction of the adrenal cortex. Low prevalence and complex inheritance have long hindered successful genetic studies. We here report the first genome-wide association study on AAD, which identifies nine independent risk loci (P < 5 × 10^-8). In addition to loci implicated in lymphocyte function and development shared with other autoimmune diseases such as HLA, BACH2, PTPN22 and CTLA4, we associate two protein-coding alterations in Autoimmune Regulator (AIRE) with AAD. The strongest, p.R471C (rs74203920, OR = 3.4 (2.7-4.3), P = 9.0 × 10^-25) introduces an additional cysteine residue in the zinc-finger motif of the second PHD domain of the AIRE protein. This unbiased elucidation of the genetic contribution to development of AAD points to the importance of central immunological tolerance, and explains 35-41% of heritability (h²).

Multiple inducers and novel roles of autoantibodies against the obligatory NMDAR subunit NR1: a translational study from chronic life stress to brain injury

Circulating autoantibodies (AB) of different immunoglobulin classes (IgM, IgA, and IgG), directed against the obligatory N-methyl-D-aspartate-receptor subunit NR1 (NMDAR1-AB), belong to the mammalian autoimmune repertoire, and appear with age-dependently high seroprevalence across health and disease. Upon access to the brain, they can exert NMDAR-antagonistic/ketamine-like actions. Still unanswered key questions, addressed here, are conditions of NMDAR1-AB formation/boosting, intraindividual persistence/course in serum over time, and (patho)physiological significance of NMDAR1-AB in modulating neuropsychiatric phenotypes. We demonstrate in a translational fashion from mouse to human that (1) serum NMDAR1-AB fluctuate upon long-term observation, independent of blood-brain barrier (BBB) perturbation; (2) a standardized small brain lesion in juvenile mice leads to increased NMDAR1-AB seroprevalence (IgM + IgG), together with enhanced Ig-class diversity; (3) CTLA4 (immune-checkpoint) genotypes, previously found associated with autoimmune disease, predispose to serum NMDAR1-AB in humans; (4) finally, pursuing our prior findings of an early increase in NMDAR1-AB seroprevalence in human migrants, which implicated chronic life stress as inducer, we independently replicate these results with prospectively recruited refugee minors. Most importantly, we here provide the first experimental evidence in mice of chronic life stress promoting serum NMDAR1-AB (IgA). Strikingly, stress-induced depressive-like behavior in mice and depression/anxiety in humans are reduced in NMDAR1-AB carriers with compromised BBB where NMDAR1-AB can readily reach the brain. To conclude, NMDAR1-AB may have a role as endogenous NMDAR antagonists, formed or boosted under various circumstances, ranging from genetic predisposition to, e.g., tumors, infection, brain injury, and stress, altogether increasing over lifetime, and exerting a spectrum of possible effects, also including beneficial functions.

Primary Adrenal Insufficiency due to Immune Checkpoint Inhibitors: More Common than We Thought

Immunotherapy has changed the treatment landscape for cancer patients; however, immune-related adverse events, such as primary and secondary adrenal insufficiency, can be life threatening, with potential differences in population incidence. This letter to the editor reports a real-world experience of Hispanic/Latino patients treated with immunotherapy and the incidence of adrenal insufficiency.

[Assessment of autoantibodies against 21-hydroxylase in the diagnosis of primary autoimmune adrenal insufficiency]

Primary adrenal insufficiency is manifested by a deficiency of adrenal cortex hormones and can lead to a life-threatening condition. Early diagnosis is key to patient survival. Auto-antibodies to one of the adrenal steroidogenesis enzymes, 21-hydroxylase, are an immunological marker of autoimmune adrenal insufficiency. On the one hand, the study of antibodies to 21-hydroxylase is a method that helps establish the etiology of the disease &ndash; the autoimmune genesis of adrenal gland damage. On the other hand, the determination of autoantibodies to 21-hydroxylase is the only prognostic factor of the risk of adrenal insufficiency, which makes it possible to prevent the development of acute adrenal crisis. The article provides a brief literature review on autoantibodies to 21-hydroxylase and the pathogenesis of autoimmune adrenal insufficiency, and a series of clinical cases that illustrates the significant role of autoantibodies to 21-hydroxylase in diagnosis of adrenal insufficiency.

Autoimmune polyglandular syndrome type II with co-manifestation of Addison's and Graves' disease in a 15-year-old boy: case report and literature review

Background Autoimmune polyglandular syndrome type II (APS II) is defined as the combination of autoimmune adrenal insufficiency and autoimmune thyroid disease (AITD) and/or type I diabetes mellitus (T1DM) in the same patient. Case presentation A 15-year-old boy had a history of weight loss, nausea and vomiting, headache, restlessness, and tanned skin. He was diagnosed with Graves' disease. Two weeks after carbimazol therapy was commenced, he presented with adrenal crises (fever, arterial hypotension, hyponatremia, adrenocorticotropic hormone [ACTH] 1119.6 ng/mL [normal range <60] and low cortisol). He received hydrocortisone and fludrocortisone, and improved quickly. Thyroid-stimulating hormone (TSH) receptor autoantibodies as well as 21-hydroxylase antibodies were elevated. Conclusions Although the combination of Graves' and Addison's disease is extremely rare, especially in children, it is critical to make the diagnosis. Accelerated metabolic rate increased the risk for adrenal crises in our patient. This case contributes to the spectrum of APS II and its manifestation.

Immune checkpoint inhibitors and type 1 diabetes mellitus: a case report and systematic review

OBJECTIVE

To better define the rare adverse event (AE) of diabetes mellitus associated with immune checkpoint inhibitors (ICIs).

DESIGN AND METHODS

We report the case of a lung cancer patient with diabetic ketoacidosis (DKA) and autoimmune thyroiditis during pembrolizumab treatment. We provide a systematic review of all published cases (PubMed/Web of Science/Cochrane, through November 2018) of autoimmune diabetes mellitus related to blockade of the cytotoxic T-lymphocyte antigen 4 (CTLA-4)-, programmed cell death 1 (PD-1) receptor or its ligand (PD-L1) or combination (ICI) therapy.

RESULTS

Our literature search identified 90 patient cases (our case excluded). Most patients were treated with anti-PD-1 or anti-PD-L1 as monotherapy (79%) or in combination with CTLA-4 blockade (15%). On average, diabetes mellitus was diagnosed after 4.5 cycles; earlier for combination ICI at 2.7 cycles. Early-onset diabetes mellitus (after one or two cycles) was observed during all treatment regimens. Diabetic ketoacidosis was present in 71%, while elevated lipase levels were detected in 52% (13/25). Islet autoantibodies were positive in 53% of patients with a predominance of glutamic acid decarboxylase antibodies. Susceptible HLA genotypes were present in 65% (mostly DR4). Thyroid dysfunction was the most frequent other endocrine AE at 24% incidence in this patient population.

CONCLUSION

ICI-related diabetes mellitus is a rare but often life-threatening metabolic urgency of which health-care professionals and patients should be aware. Close monitoring of blood glucose and prompt endocrine investigation in case of hyperglycemia is advisable. Predisposing factors such as HLA genotype might explain why some individuals are at risk.

The Immune Landscape of Thyroid Cancer in the Context of Immune Checkpoint Inhibition

Immune cells play critical roles in tumor prevention as well as initiation and progression. However, immune-resistant cancer cells can evade the immune system and proceed to form tumors. The normal microenvironment (immune cells, fibroblasts, blood and lymphatic vessels, and interstitial extracellular matrix (ECM)) maintains tissue homeostasis and prevents tumor initiation. Inflammatory mediators, reactive oxygen species, cytokines, and chemokines from an altered microenvironment promote tumor growth. During the last decade, thyroid cancer, the most frequent cancer of the endocrine system, has emerged as the fifth most incident cancer in the United States (USA), and its incidence is steadily growing. Inflammation has long been associated with thyroid cancer, raising critical questions about the role of immune cells in its pathogenesis. A plethora of immune cells and their mediators are present in the thyroid cancer ecosystem. Monoclonal antibodies (mAbs) targeting immune checkpoints, such as mAbs anti-cytotoxic T lymphocyte antigen 4 (anti-CTLA-4) and anti-programmed cell death protein-1/programmed cell death ligand-1 (anti-PD-1/PD-L1), have revolutionized the treatment of many malignancies, but they induce thyroid dysfunction in up to 10% of patients, presumably by enhancing autoimmunity. Combination strategies involving immune checkpoint inhibitors (ICIs) with tyrosine kinase (TK) or serine/threonine protein kinase B-raf (BRAF) inhibitors are showing considerable promise in the treatment of advanced thyroid cancer. This review illustrates how different immune cells contribute to thyroid cancer development and the rationale for the antitumor effects of ICIs in combination with BRAF/TK inhibitors.

Role of CTLA4 A49G polymorphism in systemic lupus erythematosus and its geographical distribution

CTLA-4 (cytotoxic T-lymphocyte-associated protein-4) or CD152 is an inhibitory receptor expressed constitutively on CD4+ CD25+ T regulatory lymphocytes and transiently on activated CD4+ and CD8+ T lymphocytes. Its inhibitory function promotes long-lived anergy in immune cells and prevents autoimmunity. Therefore, it plays a crucial role in T cell-mediated autoimmunity, and thus in susceptibility to autoimmune diseases, including systemic lupus erythematosus (SLE). It is encoded by CTLA4 gene in humans. AtoG polymorphism at position +49 of CTLA4 gene is the only polymorphism which changes amino acid sequence from alanine to threonine in the leader sequence, which may affect the function of CTLA-4. Association of CTLA4 polymorphisms with SLE has been investigated in several reports in different ethnic populations from different countries, which have shown highly inconsistent findings. In this review, we have compiled previous studies which have reported the association of CTLA4 A49G polymorphism in SLE and its geographical distribution.

Safety of combining radiotherapy with immune-checkpoint inhibition

Immune-checkpoint inhibitors targeting cytotoxic T- lymphocyte antigen 4 (CTLA-4), programmed cell death protein 1 (PD-1), or programmed cell death 1 ligand 1 (PD-L1) have transformed the care of patients with a wide range of advanced-stage malignancies. More than half of these patients will also have an indication for treatment with radiotherapy. The effects of both radiotherapy and immune-checkpoint inhibition (ICI) involve a complex interplay with the innate and adaptive immune systems, and accumulating evidence suggests that, under certain circumstances, the effects of radiotherapy synergize with those of ICI to augment the antitumour responses typically observed with either modality alone and thus improve clinical outcomes. However, the mechanisms by which radiotherapy and immune-checkpoint inhibitors synergistically modulate the immune response might also affect both the type and severity of treatment-related toxicities. Moreover, in patients receiving immune-checkpoint inhibitors, the development of immune-related adverse events has been linked with superior treatment responses and patient survival durations, suggesting a relationship between the antitumour and adverse autoimmune effects of these agents. In this Review, we discuss the emerging data on toxicity profiles related to immune-checkpoint inhibitors and radiotherapy, both separately and in combination, their potential mechanisms, and the approaches to managing these toxicities.

Endocrine Toxicity of Cancer Immunotherapy Targeting Immune Checkpoints

Immune checkpoints are small molecules expressed by immune cells that play critical roles in maintaining immune homeostasis. Targeting the immune checkpoints cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed death 1 (PD-1) with inhibitory antibodies has demonstrated effective and durable antitumor activity in subgroups of patients with cancer. The US Food and Drug Administration has approved several immune checkpoint inhibitors (ICPis) for the treatment of a broad spectrum of malignancies. Endocrinopathies have emerged as one of the most common immune-related adverse events (irAEs) of ICPi therapy. Hypophysitis, thyroid dysfunction, insulin-deficient diabetes mellitus, and primary adrenal insufficiency have been reported as irAEs due to ICPi therapy. Hypophysitis is particularly associated with anti-CTLA-4 therapy, whereas thyroid dysfunction is particularly associated with anti-PD-1 therapy. Diabetes mellitus and primary adrenal insufficiency are rare endocrine toxicities associated with ICPi therapy but can be life-threatening if not promptly recognized and treated. Notably, combination anti-CTLA-4 and anti-PD-1 therapy is associated with the highest incidence of ICPi-related endocrinopathies. The precise mechanisms underlying these endocrine irAEs remain to be elucidated. Most ICPi-related endocrinopathies occur within 12 weeks after the initiation of ICPi therapy, but several have been reported to develop several months to years after ICPi initiation. Some ICPi-related endocrinopathies may resolve spontaneously, but others, such as central adrenal insufficiency and primary hypothyroidism, appear to be persistent in most cases. The mainstay of management of ICPi-related endocrinopathies is hormone replacement and symptom control. Further studies are needed to determine (i) whether high-dose corticosteroids in the treatment of ICPi-related endocrinopathies preserves endocrine function (especially in hypophysitis), and (ii) whether the development of ICPi-related endocrinopathies correlates with tumor response to ICPi therapy.

Tipping the balance: inhibitory checkpoints in intestinal homeostasis

The small intestinal and colonic lamina propria are populated with forkhead box P3 (FOXP3)⁺CD4⁺ regulatory T cells (Tregs) and interleukin-10-producing T cells that orchestrate intestinal tolerance to harmless microbial and food antigens. Expression of co-inhibitory receptors such as CTLA-4 and PD-1 serve as checkpoints to these cells controlling their T-cell receptor (TCR)-mediated and CD28-mediated activation and modulating the phenotype of neighboring antigen presenting cells. Recent discoveries on the diversity of co-inhibitory receptors and their selective cellular expression has shed new light on their tissue-dependent function. In this review, we provide an overview of the co-inhibitory pathways and checkpoints of Treg and effector T cells and their mechanisms of action in intestinal homeostasis. Better understanding of these inhibitory checkpoints is desired as their blockade harbors clinical potential for the treatment of cancer and their stimulation may offer new opportunities to treat chronic intestinal inflammation such as inflammatory bowel disease.

Common genetic variation in the autoimmune regulator (AIRE) locus is associated with autoimmune Addison's disease in Sweden

Autoimmune Addison's disease (AAD) is the predominating cause of primary adrenal failure. Despite its high heritability, the rarity of disease has long made candidate-gene studies the only feasible methodology for genetic studies. Here we conducted a comprehensive reinvestigation of suggested AAD risk loci and more than 1800 candidate genes with associated regulatory elements in 479 patients with AAD and 2394 controls. Our analysis enabled us to replicate many risk variants, but several other previously suggested risk variants failed confirmation. By exploring the full set of 1800 candidate genes, we further identified common variation in the autoimmune regulator (AIRE) as a novel risk locus associated to sporadic AAD in our study. Our findings not only confirm that multiple loci are associated with disease risk, but also show to what extent the multiple risk loci jointly associate to AAD. In total, risk loci discovered to date only explain about 7% of variance in liability to AAD in our study population.

Autoimmune Addison's disease - An update on pathogenesis

Autoimmunity against the adrenal cortex is the leading cause of Addison's disease in industrialized countries, with prevalence estimates ranging from 93-220 per million in Europe. The immune-mediated attack on adrenocortical cells cripples their ability to synthesize vital steroid hormones and necessitates life-long hormone replacement therapy. The autoimmune disease etiology is multifactorial involving variants in immune genes and environmental factors. Recently, we have come to appreciate that the adrenocortical cell itself is an active player in the autoimmune process. Here we summarize the complex interplay between the immune system and the adrenal cortex and highlight unanswered questions and gaps in our current understanding of the disease.

Biomarkers for immune-related toxicities of checkpoint inhibitors: current progress and the road ahead

INTRODUCTION

Immune checkpoint pathways are key immune regulatory pathways that play a physiologic role in maintaining immune-homeostasis and are often co-opted by cancer cells to evade the host immune system. Recent developments in cancer immunotherapy, mainly drugs blocking the immune checkpoint pathways, have revolutionized the treatment paradigm for many solid tumors. A wide spectrum of immune-related adverse events (irAEs) have been described with the use of these agents which necessitate treatment with immunosuppression, lead to disruption of therapy and can on occasion be life-threatening. There are currently no clinically validated biomarkers to predict the risk of irAEs. Areas covered: In this review, the authors describe the current progress in identifying biomarkers for irAEs and potential future directions. Literature search was conducted using PubMed-MEDLINE, Embase and Scopus. In addition, abstracts from major conference proceedings were reviewed for relevant content. Expert commentary: The discovery of biomarkers for irAEs is currently in its infancy, however there are a lot of promising candidate biomarkers that are currently being investigated. Biomarkers that can identify patients at a higher risk of developing irAEs or lead to early detection of autoimmune toxicities are crucial to optimize patient selection for immune-oncology agents and to minimize toxicity with their use.

Evaluation of the genetic basis of primary hypoadrenocorticism in Standard Poodles using SNP array genotyping and whole-genome sequencing

Primary hypoadrenocorticism, also known as Addison's disease, is an autoimmune disorder leading to the destruction of the adrenal cortex and subsequent loss of glucocorticoid and mineralocorticoid hormones. The disease is prevalent in Standard Poodles and is believed to be highly heritable in the breed. Using genotypes derived from the Illumina Canine HD SNP array, we performed a genome-wide association study of 133 carefully phenotyped Standard Poodles (61 affected, 72 unaffected) and found no markers significantly associated with the disease. We also sequenced the entire genomes of 20 Standard Poodles (13 affected, 7 unaffected) and analyzed the data to identify common variants (including SNPs, indels, structural variants, and copy number variants) across affected dogs and variants segregating within a single pedigree of highly affected dogs. We identified several candidate genes that may be fixed in both Standard Poodles and a small population of dogs of related breeds. Further studies are required to confirm these findings more broadly, as well as additional gene-mapping efforts aimed at fully understanding the genetic basis of what is likely a complex inherited disorder.

Association of the CTLA4 gene CT60/rs3087243 single-nucleotide polymorphisms with Graves' disease

It has been widely reported that the CT60 single-nucleotide polymorphism (SNP), which is in the 3'-untranslated region of the cytotoxic T lymphocyte associated 4 (CTLA4) gene, is strongly correlated with certain immune-mediated diseases. The present case-control study aimed to investigate the genetic association between the CT60 SNP within the CTLA4 gene and Graves' disease (GD). A total of 288 patients with GD and 290 control subjects were recruited for the study. The CT60 SNP of the CTLA4 gene was detected by direct DNA sequencing. The results indicated that the frequencies of the GG genotype and G allele in the case group were evidently higher than that in the control group (P=4×10^-6 and P=2.9×10^-5, respectively). Furthermore, the G/G genotype of the CT60 SNP was associated with an increased risk for GD (odds ratio=2.223). In conclusion, these results suggested that the CT60 SNP is associated with susceptibility to GD. The frequency of the disease-susceptible G allele of CT60 was significantly associated with an increased risk of GD development.

CTLA-4 as a genetic determinant in autoimmune Addison's disease

In common with several other autoimmune diseases, autoimmune Addison's disease (AAD) is thought to be caused by a combination of deleterious susceptibility polymorphisms in several genes, together with undefined environmental factors and stochastic events. To date, the strongest genomic association with AAD has been with alleles at the HLA locus, DR3-DQ2 and DR4. The contribution of other genetic variants has been inconsistent. We have studied the association of 16 single-nucleotide polymorphisms (SNPs) within the CD28-CTLA-4-ICOS genomic locus, in a cohort comprising 691 AAD patients of Norwegian and UK origin with matched controls. We have also performed a meta-analysis including 1002 patients from European countries. The G-allele of SNP rs231775 in CTLA-4 is associated with AAD in Norwegian patients (odds ratio (OR)=1.35 (confidence interval (CI) 1.10-1.66), P=0.004), but not in UK patients. The same allele is associated with AAD in the total European population (OR=1.37 (CI 1.13-1.66), P=0.002). A three-marker haplotype, comprising PROMOTER_1661, rs231726 and rs1896286 was found to be associated with AAD in the Norwegian cohort only (OR 2.43 (CI 1.68-3.51), P=0.00013). This study points to the CTLA-4 gene as a susceptibility locus for the development of AAD, and refines its mapping within the wider genomic locus.

Linkage Analysis in Autoimmune Addison's Disease: NFATC1 as a Potential Novel Susceptibility Locus

Background

Autoimmune Addison’s disease (AAD) is a rare, highly heritable autoimmune endocrinopathy. It is possible that there may be some highly penetrant variants which confer disease susceptibility that have yet to be discovered.

Methods

DNA samples from 23 multiplex AAD pedigrees from the UK and Norway (50 cases, 67 controls) were genotyped on the Affymetrix SNP 6.0 array. Linkage analysis was performed using Merlin. EMMAX was used to carry out a genome-wide association analysis comparing the familial AAD cases to 2706 UK WTCCC controls. To explore some of the linkage findings further, a replication study was performed by genotyping 64 SNPs in two of the four linked regions (chromosomes 7 and 18), on the Sequenom iPlex platform in three European AAD case-control cohorts (1097 cases, 1117 controls). The data were analysed using a meta-analysis approach.

Results

In a parametric analysis, applying a rare dominant model, loci on chromosomes 7, 9 and 18 had LOD scores >2.8. In a non-parametric analysis, a locus corresponding to the HLA region on chromosome 6, known to be associated with AAD, had a LOD score >3.0. In the genome-wide association analysis, a SNP cluster on chromosome 2 and a pair of SNPs on chromosome 6 were associated with AAD (P <5x10^-7). A meta-analysis of the replication study data demonstrated that three chromosome 18 SNPs were associated with AAD, including a non-synonymous variant in the NFATC1 gene.

Conclusion

This linkage study has implicated a number of novel chromosomal regions in the pathogenesis of AAD in multiplex AAD families and adds further support to the role of HLA in AAD. The genome-wide association analysis has also identified a region of interest on chromosome 2. A replication study has demonstrated that the NFATC1 gene is worthy of future investigation, however each of the regions identified require further, systematic analysis.

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.

Endocrine-related adverse events following ipilimumab in patients with advanced melanoma: a comprehensive retrospective review from a single institution

Novel immune checkpoint blockade with ipilimumab, an antibody blocking the cytotoxic T-lymphocyte antigen 4 (CTLA4), is revolutionizing cancer therapy. However, ipilimumab induces symptomatic, sometimes severe, endocrine immune-related adverse events (irAEs) that are inconsistently recognized and reported. The objective of this review was to comprehensively characterize the incidence, presentation, and management of endocrinopathies following ipilimumab therapy in a single center that is highly specialized in immune checkpoint blockade. We carried out a retrospective analysis of endocrine irAEs in melanoma patients receiving ipilimumab therapy in clinical trials between 2007 and 2013. A total of 256 patients were included in this analysis. We reviewed pituitary-, thyroid-, and adrenal-related hormone test results, as well as radiographic studies and the clinical histories of patients, to identify and characterize cases of hypophysitis, hypothyroidism, thyroiditis, and adrenal dysfunction. Following ipilimumab therapy, the overall incidence of hypophysitis was 8% and that of hypothyroidism/thyroiditis 6%. Primary adrenal dysfunction was rare. Therapy with a combination of ipilimumab and nivolumab, an anti-programmed cell death 1 (PDCD1, also called PD1) receptor antibody, was associated with a 22% incidence of either thyroiditis or hypothyroidism and a 9% incidence of hypophysitis. Symptomatic relief, in particular, for hypophysitis, was achieved in all patients with hormone replacement, although endogenous hormone secretion rarely recovered. In summary, we observed that CTLA4 blockade alone, and in particular in combination with PD1 blockade, is associated with an increased risk of symptomatic, sometimes severe, hypophysitis as well as thyroid dysfunction. Prompt initiation with hormone replacement reverses symptoms. Evaluation and reporting of endocrine irAEs in clinical trials should be done using standardized diagnostic criteria and terminology.

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.

Alternative splice forms of CTLA-4 induced by antisense mediated splice-switching influences autoimmune diabetes susceptibility in NOD mice

Activated and regulatory T cells express the negative co-stimulatory molecule cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) that binds B7 on antigen-presenting cells to mediate cellular responses. Single nucleotide polymorphisms in the CTLA-4 gene have been found to affect alternative splicing and are linked to autoimmune disease susceptibility or resistance. Increased expression of a soluble splice form (sCTLA-4), lacking the transmembrane domain encoded by exon 3, has been shown to accelerate autoimmune pathology. In contrast, an exon 2-deficient form lacking the B7 ligand binding domain (liCTLA-4), expressed by diabetes resistant mouse strains has been shown to be protective when expressed as a transgene in diabetes susceptible non-obese diabetic (NOD) mice. We sought to employ an antisense-targeted splice-switching approach to independently produce these CTLA-4 splice forms in NOD mouse T cells and observe their relative impact on spontaneous autoimmune diabetes susceptibility. In vitro antisense targeting of the splice acceptor site for exon 2 produced liCTLA-4 while targeting exon 3 produced the sCTLA-4 form in NOD T cells. The liCTLA-4 expressing T cells exhibited reduced activation, proliferation and increased adhesion to intercellular adhesion molecule-1 (ICAM-1) similar to treatment with agonist α-CTLA-4. Mice treated to produce liCTLA-4 at the time of elevated blood glucose levels exhibited a significant reduction in the incidence of insulitis and diabetes, whereas a marked increase in the incidence of both was observed in animals treated to produce sCTLA-4. These findings provide further support that alternative splice forms of CTLA-4 affects diabetes susceptibility in NOD mice and demonstrates the therapeutic utility of antisense mediated splice-switching for modulating immune responses.

Insights into type 1 diabetes from the autoimmune polyendocrine syndromes

PURPOSE OF REVIEW

Advances in human genetics and investigations in animal models of autoimmune disease have allowed insight into the basic mechanisms of immunologic tolerance. These advances allow us to understand the pathogenesis of type 1 diabetes and other autoimmune diseases as never before. Here, we discuss the tolerance mechanisms of the autoimmune polyendocrine syndromes and their relevance to type 1 diabetes.

RECENT FINDINGS

Defects in central tolerance with alteration of self-antigen expression levels in the thymus are a potent cause of autoimmunity. Peripheral tolerance defects that alter T-cell activation and signaling also play an important role in the pathogenesis of diabetes and other associated autoimmune disorders, with multiple modest defects working in concert to produce disease. Regulation of the immune response through the action of regulatory T cells is a potent mode of tolerance induction in autoimmunity that is important in type 1 diabetes.

SUMMARY

Rare syndromes of autoimmunity provide a valuable window into the breakdown of tolerance and identify multiple checkpoints that are critical for generation of autoimmunity. Understanding the application of these in type 1 diabetes will allow the development of future immunomodulatory therapies in the treatment and prevention of disease.

PTPN22 gene polymorphism in Egyptian alopecia areata patients and its impact on response to diphencyprone immunotherapy

PTPN22 1858C>T gene polymorphism has been associated with several autoimmune disorders including alopecia areata. The aim of the current study was to investigate the effect of the inherited genetic polymorphism 1858C>T of PTPN22 gene on the predisposition to severe forms of alopecia areata and its effect on the response to DPC treatment. To achieve our aim, PTPN22 1858C>T genotyping was performed by PCR-based restricted fragment length polymorphism (PCR-RFLP) analysis. The study included 103 Egyptian patients with extensive alopecia areata treated by DPC. Hundred healthy age and sex matched blood donors were included in the current study as a control group. Results of genotyping showed that PTPN22 CT and TT mutant genotypes were significantly higher in AA patients compared to controls and conferred increase risk of AA (OR=2.601, 95% CI=1.081-6.255). Statistical comparison between AA patients with wild and mutant genotypes revealed that the duration of the illness was significantly longer in those harboring the mutant genotypes. Moreover, the association of other autoimmune diseases as atopy and diabetes mellitus was higher in patients with mutant genotypes. Furthermore, PTPN22 1858C>T genetic polymorphism did not affect the patients' response to DPC immunotherapy.

MHC class II association study in eight breeds of dog with hypoadrenocorticism

Canine hypoadrenocorticism is an endocrine disorder characterised by inadequate secretion of steroid hormones from the adrenal glands. Pathology results from immune-mediated destruction of the adrenal cortex, which is similar to that seen in the human Addison's disease. Both the canine and human diseases have similar clinical presentation, with the diagnosis based on performing a dynamic adrenocorticotropic hormone stimulation test. MHC class II has previously been associated with the human and canine diseases. In the current study, we conducted an MHC class II association study in eight breeds of dog with diagnoses of hypoadrenocorticism. We demonstrated significant differences in dog leukocyte antigen (DLA) haplotype frequencies in six of these breeds: Cocker spaniel, Springer spaniel, Labrador, West Highland white terrier (WHWT), Bearded collie, and Standard poodle. In the Springer spaniel, the DLA-DRB1*015:01--DQA1*006:01--DQB1*023:01 haplotype was significantly associated with disease risk (p = 0.014, odds ratio (OR) = 5.14) and showed a similar trend in the Cocker spaniel. This haplotype is related to one associated with hypoadrenocorticism in the Nova Scotia duck tolling retriever. Similar haplotypes shared between breeds were demonstrated, with DLA-DRB1*001:01--DQA1*001:01--DQB1*002:01 more prevalent in both affected Labrador (p = 0.0002, OR = 3.06) and WHWT (p = 0.01, OR = 2.11). Other haplotypes that have not previously been associated with the disease were identified. The inter-breed differences in DLA haplotypes associated with susceptibility to canine hypoadrenocorticism could represent divergent aetiologies. This could have implications for clinical diagnosis and future comparative studies. Alternatively, it may suggest that the gene of interest is closely linked to the MHC.

Induction of CXCL10 chemokine in adrenocortical cells by stimulation through toll-like receptor 3

Addison's disease is a prototypic organ-specific autoimmune disease affecting the adrenal cortex. The CXC chemokine ligand 10 (CXCL10) is expressed early in viral infections, and is produced by primary adrenocortical cells stimulated by certain cytokines. CXCL10 is also elevated in the serum of Addison's disease patients. We therefore investigated if the viral RNA substitute polyinosine-polycytidylic acid (poly (I:C)) could influence the cytokine induced production of CXCL10 by adrenocortical cells. We found that poly (I:C) could induce CXCL10 in NCI-H295R adrenocortical carcinoma cells, either alone or synergistically along with cytokines interferon-γ and tumor necrosis factor-α. This effect was found to be mediated by toll-like receptor 3 and both nuclear factor κB (NFκB) and signal transducer and activator of transcription-1 (STAT1), but not type I interferons, seemed to be involved. We propose that the combination of environmental and endogenous factors presented here, could contribute to the multifactorial pathogenesis of autoimmune Addison's disease.

Autoimmune Addison disease: pathophysiology and genetic complexity

Autoimmune Addison disease is a rare autoimmune disorder with symptoms that typically develop over months or years. Following the development of serum autoantibodies to the key steroidogenic enzyme, 21-hydroxylase, patients have a period of compensated or preclinical disease, characterized by elevations in adrenocortocotropic hormone and renin, before overt, symptomatic adrenal failure develops. We propose that local failure of steroidogenesis, causing breakdown of tolerance to adrenal antigens, might be a key factor in disease progression. The etiology of autoimmune Addison disease has a strong genetic component in man, and several dog breeds are also susceptible. Allelic variants of genes encoding molecules of both the adaptive and innate immune systems have now been implicated, with a focus on the immunological synapse and downstream participants in T lymphocyte antigen-receptor signaling. With the exception of MHC alleles, which contribute to susceptibility in both human and canine Addison disease, no major or highly penetrant disease alleles have been found to date. Future research into autoimmune Addison disease, making use of genome-wide association studies and next-generation sequencing technology, will address the gaps in our understanding of the etiology of this disease.

Genome-wide copy number variation (CNV) in patients with autoimmune Addison's disease

Background

Addison's disease (AD) is caused by an autoimmune destruction of the adrenal cortex. The pathogenesis is multi-factorial, involving genetic components and hitherto unknown environmental factors. The aim of the present study was to investigate if gene dosage in the form of copy number variation (CNV) could add to the repertoire of genetic susceptibility to autoimmune AD.

Methods

A genome-wide study using the Affymetrix GeneChip^® Genome-Wide Human SNP Array 6.0 was conducted in 26 patients with AD. CNVs in selected genes were further investigated in a larger material of patients with autoimmune AD (n = 352) and healthy controls (n = 353) by duplex Taqman real-time polymerase chain reaction assays.

Results

We found that low copy number of UGT2B28 was significantly more frequent in AD patients compared to controls; conversely high copy number of ADAM3A was associated with AD.

Conclusions

We have identified two novel CNV associations to ADAM3A and UGT2B28 in AD. The mechanism by which this susceptibility is conferred is at present unclear, but may involve steroid inactivation (UGT2B28) and T cell maturation (ADAM3A). Characterization of these proteins may unravel novel information on the pathogenesis of autoimmunity.

Molecular cloning, expression and characterization of the functional domain of CTLA4 from the rhesus monkey, Macaca mulatta

Cytotoxic T lymphocyte-associated antigen 4 (CTLA4) is a potent inhibitor of T cell activation. The genes encoding the membrane and soluble forms of Macaca mulatta CTLA4 (mmCTLA4) were isolated from peripheral blood mononuclear cells (PBMCs). The predicted mmCTLA4 protein is nearly identical to human CTLA4 (hCTLA4), with the exception of a serine instead of an asparagine residue at position 49 and a leucine instead of a methionine residue at position 141 of its extracellular domain. The fusion protein mmCTLA4Ig, containing the extracellular domain of mmCTLA4 and the constant region of the human IgG1 antibody, was expressed in Pichia pastoris. The mmCTLA4Ig produced by P. pastoris exhibited specific binding to human B7-positive Raji cells that could be inhibited by competitive binding of hCTLA4Ig. MmCTLA4Ig and hCTLA4Ig could comparably suppress the proliferation of lymphocytes derived from rhesus monkeys, humans, or mice that had been stimulated either by concanavalin A (Con A) or allogeneic cells. These results suggest that mmCTLA4 is a negative regulator of T cell activation and that mmCTLA4Ig may be useful for immunotherapy of immunologic diseases in the rhesus monkey.

More CLEC16A gene variants associated with multiple sclerosis

OBJECTIVES

Recently, associations of several single-nucleotide polymorphisms (SNPs) within the CLEC16A gene with multiple sclerosis (MS), type-I diabetes, and primary adrenal insufficiency were reported.

METHODS

We performed linkage disequilibrium (LD) fine mapping with 31 SNPs from this gene, searching for the region of highest association with MS in a German sample consisting of 603 patients and 825 controls.

RESULTS

Four SNPs located in intron 19 of the CLEC16A gene were found associated. We could replicate the finding for SNP rs725613 and were able to show for the first time the association of rs2041670, rs2080272 and rs998592 with MS.

CONCLUSION

All described base polymorphisms are mapping to one LD block of approximately 50 kb within intron 19 of the CLEC16A gene, suggesting a pivotal role of this region for susceptibility of MS and possibly also for other autoimmune diseases.

Examination of candidate genes for hypoadrenocorticism in Nova Scotia Duck Tolling Retrievers

Inherited hypoadrenocorticism occurs in some dog breeds including the Nova Scotia Duck Tolling Retriever (NSDTR) and is thought to be due to an immune attack on the adrenal glands. The genetic cause of this disorder in dogs has not been identified; however, many genes have been associated with hypoadrenocorticism and other immune-mediated conditions in humans including AIRE, BAFF, Casp10, CD28, CTLA-4, FASL, PTPN22, and TNFRSF6B. Microsatellite marker loci were analysed for linkage with the disease phenotype in a pedigree of NSDTRs and excluded all genes examined, the exception being CTLA-4, which was neither excluded nor shown to be associated by this analysis. Thus, genes associated with hypoadrenocorticism in humans were not linked with the condition in the dog. Further examination is necessary to identify the genetic cause of inherited hypoadrenocorticism in dogs and this may reveal a novel gene not yet implicated with immune-mediated disease.

Cellular immunity and immunopathology in autoimmune Addison's disease

Autoimmune adrenocortical failure, or Addison's disease, is a prototypical organ-specific autoimmune disorder. In common with related autoimmune endocrinopathies, Addison's disease is only manageable to a certain extent with replacement therapy being the only treatment option. Unfortunately, the available therapy does not restore the physiological hormone levels and biorhythm. The key to progress in treating and preventing autoimmune Addison's disease lies in improving our understanding of the predisposing factors, the mechanisms responsible for the progression of the disease, and the interactions between adrenal antigens and effector cells and molecules of the immune system. The aim of the present review is to summarize the current knowledge on the role of T cells and cellular immunity in the pathogenesis of autoimmune Addison's disease.

Genetics of type 1 diabetes

BACKGROUND

Type 1 diabetes, a multifactorial disease with a strong genetic component, is caused by the autoimmune destruction of pancreatic β cells. The major susceptibility locus maps to the HLA class II genes at 6p21, although more than 40 non-HLA susceptibility gene markers have been confirmed.

CONTENT

Although HLA class II alleles account for up to 30%-50% of genetic type 1 diabetes risk, multiple non-MHC loci contribute to disease risk with smaller effects. These include the insulin, PTPN22, CTLA4, IL2RA, IFIH1, and other recently discovered loci. Genomewide association studies performed with high-density single-nucleotide-polymorphism genotyping platforms have provided evidence for a number of novel loci, although fine mapping and characterization of these new regions remain to be performed. Children born with the high-risk genotype HLADR3/4-DQ8 comprise almost 50% of children who develop antiislet autoimmunity by the age of 5 years. Genetic risk for type 1 diabetes can be further stratified by selection of children with susceptible genotypes at other diabetes genes, by selection of children with a multiple family history of diabetes, and/or by selection of relatives that are HLA identical to the proband.

SUMMARY

Children with the HLA-risk genotypes DR3/4-DQ8 or DR4/DR4 who have a family history of type 1 diabetes have more than a 1 in 5 risk for developing islet autoantibodies during childhood, and children with the same HLA-risk genotype but no family history have approximately a 1 in 20 risk. Determining extreme genetic risk is a prerequisite for the implementation of primary prevention trials, which are now underway for relatives of individuals with type 1 diabetes.

CTLA4 CT60 single-nucleotide polymorphism is associated with Slovenian inflammatory bowel disease patients and regulates expression of CTLA4 isoforms

We have evaluated functional polymorphism (rs3087243; in literature known also as CTLA4 CT60) in the cytotoxic T lymphocyte antigen 4 (CTLA4) gene, previously associated with several autoimmune diseases, for potential association with inflammatory bowel diseases (IBD). In addition, we investigated correlations between CTLA4 CT60 polymorphism and CTLA4 gene expression in peripheral blood lymphocytes and colon biopsies from IBD patients. We genotyped CTLA4 CT60 polymorphism in 266 healthy control subjects and 481 IBD patients and found statistically lower frequency of CTLA4 CT60 AA genotype in IBD patients (13.72%) compared to control subjects (23.31%; p&#x2009;=&#x2009;0.001, odds ratio [OR]&#x2009;=&#x2009;0.504) as well as lower allele frequency of minor A allele in IBD patients (0.346) compared to control subjects (0.461, p&#x2009;&lt;&#x2009;0.001, OR&#x2009;=&#x2009;0.623). The association was confirmed with both major forms of IBD, Crohn's disease, and ulcerative colitis (UC), but was slightly stronger in UC patients, particularly when we compared allele frequency of A allele in UC patients (0.299) and control subjects (0.461, p&#x2009;&lt;&#x2009;0.001, OR&#x2009;=&#x2009;0.500). We found lower expression of the CTLA4 gene in blood lymphocytes from IBD patients compared to control subjects (p&#x2009;&lt;&#x2009;0.001) and higher CTLA4 expression in biopsies taken from inflamed part of the colon compared to noninflamed part of the colon (p&#x2009;=&#x2009;0.021). We found lower expression of soluble CTLA4 isoform than membrane-bound full-length isoform in peripheral blood lymphocytes from IBD patients compared to control subjects (p&#x2009;=&#x2009;0.010) and in lymphocytes from IBD patients with CTLA4 CT60 GG genotype compared to IBD patients with AA genotype (p&#x2009;=&#x2009;0.034). Our genotype and gene expression data suggest that CTLA4 plays a role in IBD pathogenesis. Polymorphism CTLA4 CT60 contributes to genetic susceptibility to IBD in Slovenian population and regulates expression of CTLA4 isoforms.

Haplotype analysis discriminates genetic risk for DR3-associated endocrine autoimmunity and helps define extreme risk for Addison's disease

CONTEXT

Multiple autoimmune disorders (e.g. Addison's disease, type 1 diabetes, celiac disease) are associated with HLA-DR3, but it is likely that alleles of additional genes in linkage disequilibrium with HLA-DRB1 contribute to disease.

OBJECTIVE

The objective of the study was to characterize major histocompatability complex (MHC) haplotypes conferring extreme risk for autoimmune Addison's disease (AD).

DESIGN, SETTING, AND PARTICIPANTS

Eighty-six 21-hydroxylase autoantibody-positive, nonautoimmune polyendocrine syndrome type 1, Caucasian individuals collected from 1992 to 2009 with clinical AD from 68 families (12 multiplex and 56 simplex) were genotyped for HLA-DRB1, HLA-DQB1, MICA, HLA-B, and HLA-A as well as high density MHC single-nucleotide polymorphism (SNP) analysis for 34.

MAIN OUTCOME MEASURES

AD and genotype were measured.

RESULT

Ninety-seven percent of the multiplex individuals had both HLA-DR3 and HLA-B8 vs. 60% of simplex AD patients (P = 9.72 × 10(-4)) and 13% of general population controls (P = 3.00 × 10(-19)). The genotype DR3/DR4 with B8 was present in 85% of AD multiplex patients, 24% of simplex patients, and 1.5% of control individuals (P = 4.92 × 10(-191)). The DR3-B8 haplotype of AD patients had HLA-A1 less often (47%) than controls (81%, P = 7.00 × 10(-5)) and type 1 diabetes patients (73%, P = 1.93 × 10(-3)). Analysis of 1228 SNPs across the MHC for individuals with AD revealed a shorter conserved haplotype (3.8) with the loss of the extended conserved 3.8.1 haplotype approximately halfway between HLA-B and HLA-A.

CONCLUSION

Extreme risk for AD, especially in multiplex families, is associated with haplotypic DR3 variants, in particular a portion (3.8) but not all of the conserved 3.8.1 haplotype.

A coding variant in NLRP1 is associated with autoimmune Addison's disease

Autoimmune Addison's disease (AAD) is a complex disorder with several susceptibility loci. Variations in the NLRP1 (previously, NALP1) gene have recently been reported to confer risk for vitiligo and associated autoimmune conditions. We hypothesized that polymorphisms in this gene may affect susceptibility to AAD. The aim of this study was to analyze the associations of six NLRP1 single-nucleotide polymorphisms (SNPs) with AAD within a Polish cohort. The study comprised 101 AAD patients and 254 healthy control individuals. Genotyping was performed by polymerase chain reaction followed by restriction fragment length polymorphism and single strand conformation polymorphism methods. The minor allele of the coding SNP rs12150220 appeared significantly more frequently in AAD compared with healthy individuals (OR = 1.5, 95% CI, 1.08-2.08, p = 0.015). The distribution of genotypes also demonstrated significant differences. The frequency of high-risk genotype AA of rs12150220 SNP was significantly increased among AAD subjects versus controls (p = 0.006 and p = 0.036, respectively; significant after Bonferroni correction), yielding an OR of 2.96 (95% CI, 1.34-6.55). Likewise, the heterozygous genotype TA was observed more frequently in the patient group [OR = 3.09 (95% CI, 1.53-6.24), p = 0.001 and p = 0.006 after Bonferroni correction]. In conclusion, this study confirms an association between the coding polymorphism in NLRP1 and AAD.

Evidence for CTLA4 as a susceptibility gene for dilated cardiomyopathy

The cytotoxic T-lymphocyte antigen 4 (CTLA4) is an inhibitory receptor expressed on activated T cells with downregulatory properties. The aim of this study was to analyse whether single-nucleotide polymorphisms (SNPs) within the CTLA4 gene are associated with the diagnosis and disease course of dilated cardiomyopathy (DCM). In two independent cohorts of DCM patients (n=251 and 223) and healthy controls (n=591), the promoter and all four exons of the CTLA4 gene, including their flanking regions, were genotyped, and the resulting allele and genotype distributions of the identified SNPs were compared between the groups. We confirmed two known SNPs in the promoter region (-318C>T) and in exon 1 (+49A>G;Thr17Ala). The allelic frequencies and genotypic distribution of the promoter SNP were similar for DCM patients compared with controls. However, the G/G genotype of the Thr17Ala variant was significantly more frequent in DCM patients compared with controls (37 out of 251 patients (14.7%) versus 44 out of 591 controls (7.4%), P=0.005). The higher frequency of the G/G genotype was confirmed in an additional DCM cohort (29 out of 223 patients (13.0%), P=0.039), indicating that this SNP functions as a risk factor for DCM. At follow-up after 1 year, the ejection fraction and the end-diastolic diameter of the left ventricle did not differ significantly between DCM patients carrying the G/G genotype versus other genotypes (n=199). Our data indicate that the common CTLA4 variant, Thr17Ala, confers susceptibility for DCM, but does not seem to influence the course of the disease 1 year after diagnosis.

Association of a functional polymorphism of PTPN22 encoding a lymphoid protein phosphatase in bilateral Meniere's disease

OBJECTIVES/HYPOTHESIS

Bilateral Meniere's disease (BMD) is a severe disease that usually results in bilateral severe or profound sensorineural hearing loss and chronic disequilibrium with loss of vestibular function. We examined single nucleotide polymorphisms (SNPs) in the PTPN22 and CTLA4 genes in Caucasian patients with BMD to assess the possible association between these polymorphism and the predisposition and clinical expression of this disease.

STUDY DESIGN

A case control study.

METHODS

The functional protein tyrosine phosphatase type 22 (PTPN22) SNP (rs2476601, 1858C/T) and CTLA4 SNP (rs231775, 49A/G) were analyzed in 52 patients with BMD and 348 healthy controls by a TaqMan 5' allelic discrimination assay. Data were analyzed by a chi(2) test with Fisher exact test.

RESULTS

No association was found between the +49A/G CTLA4 genotype and BMD patients. However, the heterozygote PTPN22 1858C/T genotype was present at a significantly higher frequency in BMD patients than in controls (odds ratio = 2.25, 95% confidence interval: 1.09-4.62; P = .04).

CONCLUSIONS

These results suggest that the PTPN22 1858C/T genotype may confer differential susceptibility to BMD in the Spanish population and support an autoimmune etiology for BMD.

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.

Associations of the CTLA-4 polymorphisms with type 1 diabetes in a Chilean population: case-parent design

CTLA-4 plays a key role in T cells regulation. We analysed the CTLA-4 +49A/G and -318C/T polymorphisms in 178 cases of type 1 diabetes and their parents (534 individuals) from Santiago, Chile. A significant overall association with T1D (p=0.028) was observed, possibly due to an overtransmission of the G-T haplotype.

Cytotoxic T lymphocyte-Associated Antigen +49G Variant Confers Risk for Anti-CCP- and Rheumatoid Factor-Positive Type of Rheumatoid Arthritis Only in Combination with CT60G Allele

Controversial observations have been published on the association of the cytotoxic T lymphocyte associated antigen gene's variants with rheumatoid arthritis (RA). After genotyping 428 patients and 230 matched controls, the prevalence of the CT60^∗G allele was more frequent in RF- and/or anti-CCP-seropositive RApatients, compared to the healthy controls (P < .001). Regression analysis revealed that the CT60^∗G allele is a possible predisposing factor for RA in these subgroups. No accumulation of the +49^∗G allele was found among patients, and this variant was not found to correlate with RA. Assaying the possible genotype variations, the +49^∗G-CT60^∗G allelic combination was accumulated in seropositive RA-subtypes, and was associated with the risk of RA (OR = 1.73, P = .001 for the whole RA-population). Although the +49^∗G allele did not mean a predisposition to RA alone, in combination with CT60^∗G it, also conferred risk, suggesting that the +49A/G variant is associated with the risk of RA only in certain haplotypes.