Association between AIRE gene polymorphism and rheumatoid arthritis: a systematic review and meta-analysis of case-control studies

Association Between AIRE Polymorphisms rs870881(C>T), rs1003854(T>C) and Rheumatoid Arthritis Risk: A Hungarian Case-control Study

BACKGROUND/AIM

Autoimmune regulator (AIRE) is a transcription factor that plays pivotal role in controlling autoimmunity. In the thymus, it supports the presentation of peripheral tissue antigens to developing T cells, where recognition of these self-antigens negatively selects the autoimmune naïve T-cells by central tolerance. Studies demonstrated that single-nucleotide polymorphisms (SNPs) in AIRE alter transcription and propagate clonal survival of autoimmune T cells, therefore increase susceptibility to autoimmune diseases. This study intended to identify SNPs in exon and intron sequences that determine AIRE transcription, where their genotypes are associated with rheumatoid arthritis (RA) risk and clinical parameters.

PATIENTS AND METHODS

After a thorough in silico research, we enrolled 100 patients with RA and 100 healthy controls to analyze the association of SNP rs870881(C>T) and rs1003854(T>C) in AIRE coding sequence with RA risk by using five different genetic models and selected clinical parameters. Multiplex quantitative polymerase chain reaction was used to determine allelic discrimination of SNPs. RA risk was assessed by odds ratios (ORs) and confidence intervals (CIs).

RESULTS

In a recessive model of rs878081, minor allele TT homozygotes were associated with RA (p=0.032, OR=5.44, 95%CI=1.16-25.52); in a recessive model of rs1003854, minor allele CC homozygotes were associated with RA (p=0.047, OR=4.84, 95%CI=1.02-23.02). Higher C-reactive protein (CRP) levels in patients with RA were significantly associated with minor allele homozygotes in recessive and codominant genetic models (p=0.029 and p=0.043, respectively) of rs1003854.

CONCLUSION

Genotypes for minor alleles of rs878081 and rs1003854 might be involved in RA pathogenesis and risk prediction.

Autoimmune Regulator Gene Polymorphisms and the Risk of Primary Immune Thrombocytopenic Purpura: A Case-Control Study

This study aimed to assess the possible association between two single nucleotide polymorphisms (SNPs) of the autoimmune regulator (AIRE) gene (rs2075876 G/A and rs760426 A/G) with the risk of primary immune thrombocytopenia (ITP), as well as AIRE serum levels, in the Egyptian population. In this case-control study, 96 cases with primary ITP and 100 healthy subjects were included. Two SNPs of the AIRE gene (rs2075876 G/A and rs760426 A/G) were genotyped via Taqman allele discrimination real-time polymerase chain reaction (PCR). Additionally, serum AIRE levels were measured using the enzyme-linked immunosorbent assay (ELISA) technique. After adjusting for age, gender, and family history of ITP, the AIRE rs2075876 AA genotype and A allele were associated with increased ITP risk (adjusted odds ratio (aOR): 4.299, p = 0.008; aOR: 1.847, p = 0.004, respectively). Furthermore, there was no significant association between AIRE rs760426 A/G different genetic models and ITP risk. A linkage disequilibrium revealed that A-A haplotypes were associated with an increased ITP risk (aOR: 1.821, p = 0.020). Serum AIRE levels were found to be significantly lower in the ITP group, positively correlated with platelet counts, and were even lower in the AIRE rs2075876 AA genotype and A allele, as well as A-G and A-A haplotype carriers (all p < 0.001). The AIRE rs2075876 genetic variants (AA genotype and A allele) and A-A haplotype are associated with an increased ITP risk in the Egyptian population and lower serum AIRE levels, whereas the SNP rs760426 A/G is not.

Autoimmunity in Primary Immunodeficiencies (PID)

Primary immunodeficiency (PID) may impact any component of the immune system. The number of PID and immune dysregulation disorders is growing steadily with advancing genetic detection methods. These expansive recognition methods have changed the way we characterize PID. While PID were once characterized by their susceptibility to infection, the increase in genetic analysis has elucidated the intertwined relationship between PID and non-infectious manifestations including autoimmunity. The defects permitting opportunistic infections to take hold may also lead the way to the development of autoimmune disease. In some cases, it is the non-infectious complications that may be the presenting sign of PID autoimmune diseases, such as autoimmune cytopenia, enteropathy, endocrinopathies, and arthritis among others, have been reported in PID. While autoimmunity may occur with any PID, this review will look at certain immunodeficiencies most often associated with autoimmunity, as well as their diagnosis and management strategies.

Autoimmune Regulator Gene Polymorphisms in Egyptian Systemic Lupus Erythematosus Patients: Preliminary Results

Background

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease. The autoimmune regulator (AIRE) is a master regulator of self-tolerance development. AIRE mutations lead to the development of autoimmune polyglandular syndrome type 1 while AIRE polymorphisms have been linked to organ-specific autoimmunity. The study is aimed at addressing the association between AIRE polymorphisms, rs2075876 (G > A) and rs760426 (A > G), and SLE susceptibility and expression in Egyptian patients.

Methods

Ninety-nine patients were included. One hundred and ten, and 123 control subjects were genotyped for rs2075876 and rs760426, respectively. Lupus severity was assessed using the Lupus Severity of Disease Index and Lupus Severity Index (LSI). Systemic Lupus International Collaborating Clinics (SLICC)/American College of Rheumatology (ACR) damage index was considered. Genotyping was done using StepOne Real-Time PCR. Results. AIRE rs760426 GG was more frequent in the patients under the genotype level (14.1% vs. 4.9%, p = 0.032) and recessive model (14.1% vs. 4.9%, p = 0.017, OR = 3.2 (1.2-8.7)). Musculoskeletal involvement and nephritis were associated with AIRE rs2075876 under the dominant (97.9% vs. 80.8%, p = 0.009, OR = 11 (1.3-89.2)) and recessive models (100% vs. 69.3%, p = 0.032), respectively; and both were linked to AIRE rs2075876 at the allelic level: 98.3% vs. 85%, p = 0.005, OR = 10.1 (1.3-76.6) and 82.8% vs. 68.6, p = 0.041, OR = 2.2 (1-4.7), respectively. Patients with AIRE rs2075876 A alleles had a higher damage index ( 1 ± 1.3 vs. 0.6 ± 1.1, p = 0.045) while the LSI was greater in patients with AIRE rs2075876 (8.5 ± 0.5 vs. 7.8 ± 1.3, p = 0.002) and rs760426 (8.6 ± 11 vs. 7.8 ± 1.2, p = 0.031) under the recessive models. Conclusion. AIRE rs760426 could share in SLE susceptibility while AIRE rs2075876 could influence the disease expression and burden in Egyptian patients.

Association of AIRE (rs2075876), but not CTLA4 (rs231775) polymorphisms with systemic lupus erythematosus

BACKGROUND

The AIRE (rs2075876) and CTLA4 (rs231775) variants have a crucial function in controlling the negative selection and suppression of T lymphocytes. Numerous reports studied the association of AIRE and CTLA4 variants with different autoimmune disorders, but with inconclusive conclusions. The main purpose of this work is to evaluate the association of these two variants with SLE susceptibility among Egyptian patients.

SUBJECTS AND METHODS

A total of 247 participants (100 SLE patients and 147 healthy controls) were enrolled in this case-controlled study. The genomic DNA of these dual variants was genotyped using the TaqMan genotyping method.

RESULTS

The AIRE (rs2075876) variant conferred protection against developing SLE disease under allelic [A allele vs. G allele; OR = 0.16, 95%CI = 0.09-0.28], and dominant [GA + AA vs. GG; OR = 0.14, 95%CI = 0.05-0.34] models. Moreover, patients with AIRE rs2075876 (A/A) genotype revealed a statistically significant with lower levels of complement 3 (p-value = 0.007). Nonetheless, the CTLA4 (rs231775) variant was not associated with increased risk of SLE under all genetic association models (p-value > 0.05). However, CTLA4 rs231775 (G/G) genotype observed significant difference with recurrent infection and hematuria.

CONCLUSIONS

Our findings indicated that the AIRE (rs2075876) variant conferred protection against developing SLE disease, but not the CTLA4 (rs231775) variant.

Thymus and autoimmunity

The thymus prevents autoimmune diseases through mechanisms that operate in the cortex and medulla, comprising positive and negative selection and the generation of regulatory T-cells (Tregs). Egress from the thymus through the perivascular space (PVS) to the blood is another possible checkpoint, as shown by some autoimmune/immunodeficiency syndromes. In polygenic autoimmune diseases, subtle thymic dysfunctions may compound genetic, hormonal and environmental cues. Here, we cover (a) tolerance-inducing cell types, whether thymic epithelial or tuft cells, or dendritic, B- or thymic myoid cells; (b) tolerance-inducing mechanisms and their failure in relation to thymic anatomic compartments, and with special emphasis on human monogenic and polygenic autoimmune diseases and the related thymic pathologies, if known; (c) polymorphisms and mutations of tolerance-related genes with an impact on positive selection (e.g. the gene encoding the thymoproteasome-specific subunit, PSMB11), promiscuous gene expression (e.g. AIRE, PRKDC, FEZF2, CHD4), Treg development (e.g. SATB1, FOXP3), T-cell migration (e.g. TAGAP) and egress from the thymus (e.g. MTS1, CORO1A); (d) myasthenia gravis as the prototypic outcome of an inflamed or disordered neoplastic ‘sick thymus’.

Analysis of the autoimmune regulator (AIRE) gene variant rs2075876 (G/A) association with breast cancer susceptibility

BACKGROUND

Recently, unexpected autoimmune regulator (AIRE) implication in the scenario of several cancers, including breast cancer (BC), has emerged. This study aims to explore for the first time the possible association between AIRE gene rs2075876 G>A variant and BC risk in a sample of the Middle East population.

METHOD

In this case-control study, we genotyped AIRE rs2075876 G>A variant in 200 unrelated patients with BC and 340 cancer-free controls using a real-time allelic discrimination polymerase chain reaction. Odds ratios (ORs) and 95% confidence intervals (CIs) were applied to estimate the strength of association under several genetic models. In silico analysis of AIRE was also executed.

RESULTS

The minor allele (A) frequency of the specified variant accounted for 0.28 in the controls. G/G homozygote was significantly more frequent among patients (94%) compared to controls (66%) (P < .001). After adjusting confounding variables, individuals with A allele conferred protection against developing BC under allelic model (OR = 0.33, 95% CI = 0.20-0.55), recessive model (OR = 0.25, 95% CI = 0.10-0.60), dominant model (OR = 0.12, 95% CI = 0.05-0.29), and homozygote comparison (OR = 0.20, 95% CI = 0.08-0.50). In silico analysis revealed AIRE enrichment in several cancer-related pathways. Kaplan-Meier plotter for the cancer databases showed association of AIRE expression with prognosis in triple-negative BC (HR = 2.44, 95% CI = 1.44-4.15, log-rank P-value < .001).

CONCLUSION

The AIRE rs2075876 G>A variant showed association with BC risk in the study population. Further large-scale replication studies in different ethnicity are warranted to confirm the findings.

Genetic Polymorphisms Associated with Rheumatoid Arthritis Development and Antirheumatic Therapy Response

Rheumatoid arthritis (RA) is the most common inflammatory arthropathy worldwide. Possible manifestations of RA can be represented by a wide variability of symptoms, clinical forms, and course options. This multifactorial disease is triggered by a genetic predisposition and environmental factors. Both clinical and genealogical studies have demonstrated disease case accumulation in families. Revealing the impact of candidate gene missense variants on the disease course elucidates understanding of RA molecular pathogenesis. A multivariate genomewide association study (GWAS) based analysis identified the genes and signalling pathways involved in the pathogenesis of the disease. However, these identified RA candidate gene variants only explain 30% of familial disease cases. The genetic causes for a significant proportion of familial RA have not been determined until now. Therefore, it is important to identify RA risk groups in different populations, as well as the possible prognostic value of some genetic variants for disease development, progression, and treatment. Our review has two purposes. First, to summarise the data on RA candidate genes and the increased disease risk associated with these alleles in various populations. Second, to describe how the genetic variants can be used in the selection of drugs for the treatment of RA.

Association of autoimmune regulator gene polymorphism with susceptibility to rheumatoid arthritis in Egyptian population

The autoimmune regulator (AIRE) gene controls autoimmunity via its transcript AIRE protein that suppresses naïve T cells during central selection. The role of AIRE polymorphism in rheumatoid arthritis (RA) autoimmunity remains elusive. This study aimed to investigate the association of two selected SNPs, namely, rs760426 and rs2075876, with RA susceptibility in the Suez Canal Zone population. The study population included 100 RA patients, and the control group included 100 healthy subjects who were age- and sex-matched to the RA group. SNP genotyping was performed using real-time polymerase chain reaction-based allelic discrimination assay, the odds ratio was defined to assess the strength of the association. For rs760426, combining genotypes data revealed a significant increase for A/G genotype in the RA cases (47%, n = 47) than in the control group (27%, n = 27) in both co-dominant and over-dominant models (P = 0.013 and 0.003 respectively). In addition, rs760426 correlated to duration of RA (P = 0.031) and anti-cyclic citrullinated peptide antibody (P = 0.021). For rs2075876, there was a significant increase in the A/A genotype in RA patients compared with control subjects. In the co-dominant model, the frequency of A/A was 14% and 7% respectively (P = 0.02). In contrast to rs760426, rs2075876 associated with the risk of increased body mass index (P = 0.014) and the positivity of rheumatoid factor (RF) (P = 0.043). The frequency of minor alleles, G allele in rs760426 SNP, and A allele in rs2075876 was higher in RA patients than in control. The haplotype frequency of both G and A alleles in rs760426 and rs2075876 receptively was 11% in RA group with statistically significant difference (P = <0.001) between RA patients and healthy control. SNPs rs760426 and rs2075876 in the AIRE gene may contribute to the risk for RA susceptibility. These two polymorphisms were associated with variable risk factors and predictive biomarkers for RA. The mutant allele (G) of rs760426 SNP has significant indication of poor prognosis.

Association of Autoimmune Regulator Gene Rs2075876 Variant, but Not Gene Expression with Alopecia Areata in Males: A Case-control Study

Alopecia areata (AA) is a non-scarring hair loss of autoimmune etiology. The autoimmune regulator (AIRE) gene is believed to be an important driver in AA pathogenesis. Genetic variants can alter mRNA expression levels which may provoke an autoimmune response. A total of 337 males (97 AA patients and 240 controls) were enrolled in the current case-control study. On screening of the most frequent variants in the gene, rs2075876 (A/G) polymorphism in intron 5 was selected and genotyped using Real-Time PCR (polymerase chain reaction) technology. Additionally, circulatory AIRE expression levels were quantified by quantitative reverse-transcription PCR (qRT-PCR). Allelic discrimination analysis revealed GG genotype to be more frequent in patients (90.7% in AA compared to 32.5% in controls, p < .001). G variant conferred increased risk to alopecia under homozygote comparison (GG versus AA: OR = 16.1, 95%CI = 5.57-46.3), dominant model (GG+AG versus AA: OR = 7.24, 95%CI = 2.5-20.5), recessive model (GG versus AG+AA: OR = 20.3, 95%CI = 9.7-42.4), and allelic model (G versus A: OR = 11.6, 95%CI = 6.47-21.1). The expression levels of AIRE gene did not differ significantly between patients and controls and were not related to rs2075876 variant. In conclusion, the intronic variant (rs2075876) is suggested to be a potent susceptibility variant for AA development in the studied population.Abbreviations: AA: Alopecia areata; AIRE: Autoimmune Regulator; APECED: Autoimmune, Polyendocrinopathy Candidiasis Ectodermal Dystrophy; DLQI: Dermatology life quality index questionnaire; MIQE: Minimum information for publication of quantitative real-time PCR experiments; mTEC: Medullary thymic epithelial cells; PHD: Plant homeodomain; qRT-PCR: Quantitative reversetranscription-polymerase chain reaction; RA: Rheumatoid arthritis.

The AIRE Ser196Ser synonymous variant is a risk factor for systemic lupus erythematosus

The AIRE gene influences the expression of a wide array of self-antigens in the thymus, and is essential to the negative selection of self-reactive T cells and establishment of central tolerance. Single nucleotide variants (SNVs) such as rs878081C/T (Ser196Ser) and rs2075876G/T at this locus have been associated with susceptibility to rheumatoid arthritis, mainly in Asian populations, but its role in systemic lupus erythematosus (SLE) has not been documented. We performed a case-control association study with 379 SLE patients and 460 controls from central Mexico. In addition, we replicated our finding in another group of 179 SLE patients and 97 controls from the same region of Mexico. In the first group, we identified that the AIRE Ser196Ser synonymous variant was associated with SLE (OR 1.4, p = 0.009), meanwhile, in the second group we observed the following: OR 1.7, p = 0.024. No association was found between these AIRE SNVs and lupus nephritis. Our results suggest that AIRE is a risk factor for SLE in our population. This study is the first to document an association between AIRE and SLE susceptibility.

Primary immunodeficiency and autoimmunity: A comprehensive review

The primary immunodeficiency diseases (PIDs) include many genetic disorders that affect different components of the innate and adaptive responses. The number of distinct genetic PIDs has increased exponentially with improved methods of detection and advanced laboratory methodology. Patients with PIDs have an increased susceptibility to infectious diseases and non-infectious complications including allergies, malignancies and autoimmune diseases (ADs), the latter being the first manifestation of PIDs in several cases. There are two types of PIDS. Monogenic immunodeficiencies due to mutations in genes involved in immunological tolerance that increase the predisposition to develop autoimmunity including polyautoimmunity, and polygenic immunodeficiencies characterized by a heterogeneous clinical presentation that can be explained by a complex pathophysiology and which may have a multifactorial etiology. The high prevalence of ADs in PIDs demonstrates the intricate relationships between the mechanisms of these two conditions. Defects in central and peripheral tolerance, including mutations in AIRE and T regulatory cells respectively, are thought to be crucial in the development of ADs in these patients. In fact, pathology that leads to PID often also impacts the Treg/Th17 balance that may ease the appearance of a proinflammatory environment, increasing the odds for the development of autoimmunity. Furthermore, the influence of chronic and recurrent infections through molecular mimicry, bystander activation and super antigens activation are supposed to be pivotal for the development of autoimmunity. These multiple mechanisms are associated with diverse clinical subphenotypes that hinders an accurate diagnosis in clinical settings, and in some cases, may delay the selection of suitable pharmacological therapies. Herein, a comprehensively appraisal of the common mechanisms among these conditions, together with clinical pearls for treatment and diagnosis is presented.

VEGF-C Gene Polymorphisms Increase Susceptibility to Rheumatoid Arthritis

Vascular endothelial growth factor C (VEGF-C) promotes angiogenesis, a prominent feature in rheumatoid synovitis, contributing to the perpetuation of the global burden of rheumatoid arthritis (RA). VEGF-C gene polymorphisms predict the risk of developing various human diseases, such as urothelial cell carcinoma, oral cancer and coronary artery disease. We sought to determine whether single nucleotide polymorphisms (SNPs) of the VEGF-C gene can predict the risk of RA. Our study recruited 210 patients with RA and 373 healthy controls between 2007 and 2015, and performed comparative genotyping for SNPs rs7664413, rs11947611, rs1485766, rs2046463 and rs3775194. In analyses adjusted for potential covariates, we found that compared with subjects with the A/A genotype of SNP rs11947611, those with the A/G genotype were 40% more likely to develop RA (adjusted odds ratio [AOR] 0.61; 95% confidence interval [CI] 0.40 to 0.92; p = 0.02). In addition, subjects lacking the A/A genotype (A/G, G/G) of SNP rs2046463 were more than twice as likely as those with the A/A genotype to require methotrexate (AOR 2.23, 95% CI 1.25 to 3.98; p = 0.01), while those who lacked the G/G genotype (G/C, C/C) in the SNP rs3775194 had a significantly lower risk of requiring prednisolone as compared with those with the G/G genotype (AOR 0.39, 95% CI 0.19 to 0.79; p = 0.01). Our findings suggest that VEGF-C gene polymorphisms might serve as a diagnostic marker and therapeutic target for RA therapy. Pharmacotherapies that modulate the activity of the VEGF-C gene may be promising for RA treatment.

The rs878081 polymorphism of AIRE gene increases the risk of rheumatoid arthritis in a Chinese Han population: a case-control study

The autoimmune regulator (AIRE), a transcriptional regulator expressed in medullary thymic epithelial cells, plays an important role in thymocyte education and negative selection. Several citations studying the association between the rs878081 exon polymorphism of the AIRE gene and the risk of rheumatoid arthritis (RA) in different populations have yielded conflicting findings. Thus, this case-control study involving 300 RA cases and 300 controls was aimed to identify whether such association existed in a Chinese Han population from East China. The rs878081 polymorphism of the AIRE gene was genotyped. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using the chi-squared test, genetic model analysis, and stratification analysis. Genetic model analysis showed significant correlations between the TT genotype and the risk of RA (OR: 1.89, 95%CI: 1.03-3.47 in TT vs CC; OR: 1.84, 95%CI: 1.02-3.31 in TT vs CC+TC). Stratification analyses of sex, age, smoking, and alcoholism suggested that the rs878081 polymorphism of the AIRE gene increased RA risk among non-smokers. In conclusion, rs878081 polymorphism of AIRE gene increases the risk of RA in a Chinese Han population.

Aire is not essential for regulating neuroinflammatory disease in mice transgenic for human autoimmune-diseases associated MHC class II genes HLA-DR2b and HLA-DR4

The human autoimmune disease-associated HLA alleles HLA-DR2b (DRB1*1501) and HLA-DR4 (DRB1*0401) are strongly linked to increased susceptibility for multiple sclerosis (MS) and rheumatoid arthritis (RA), respectively. The underlying mechanisms are not fully understood, but these MHC alleles may shape the repertoire of pathogenic T cells via central tolerance. The transcription factor autoimmune regulator (AIRE) promotes central T cell tolerance via ectopic expression of tissue-specific antigens (TSAs). Aire deficiency in humans causes autoimmune polyendocrinopathy syndrome type 1 (APS1), and Aire knockout mice (Aire-/-) develop spontaneous autoimmune pathology characterized by multi-organ lymphocytic infiltrates. Here, we asked whether impaired TSAs gene expression in the absence of Aire promoted spontaneous MS- or RA-like autoimmune pathology in the context of human HLA alleles in HLA-DR2b or HLA-DR4 transgenic (tg) mice. The results show that reduced TSAs gene expression in the thymus of Aire-deficient HLA-DR2b or HLA-DR4 tg mice corresponded to mild spontaneous inflammatory infiltrates in salivary glands, liver, and pancreas. Moreover, Aire-deficiency modestly enhanced experimental autoimmune encephalomyelitis (EAE) in HLA-DR tg mice, but the animals did not show signs of spontaneous neuroinflammation or arthritis. No significant changes were observed in CD4+ T cell numbers, T cell receptor (TCR) distribution, regulatory T cells (Treg), or antigen-induced cytokine production. Abrogating Treg function by treatment with anti-CTLA-4 or anti-CD25 mAb in Aire-deficient HLA-DR tg mice did not trigger EAE or other autoimmune pathology. Our results suggest a redundant role for Aire in maintaining immune tolerance in the context of autoimmune disease-associated human HLA alleles.

Chemokine C-C Motif Ligand 4 Gene Polymorphisms Associated with Susceptibility to Rheumatoid Arthritis

Chemokine C-C motif ligand 4 (CCL4) gene is a chemokine-encoding gene, and the polymorphism of CCL4 gene has been shown to predict risk of various diseases. We want to investigate whether the single nucleotide polymorphisms (SNPs) of the CCL4 gene can predict the risk of rheumatoid arthritis (RA). Between 2007 and 2015, we recruited 217 patients diagnosed with RA and 371 control participants. Comparative genotyping of the rs1634507, rs10491121, and rs1719153 SNPs was performed. When compared with participants with the A/A genotype of rs1719153, those with the A/T genotype were less likely to develop RA, as were those with the A/T+T/T genotype. The protective effect of the T-containing genotype was even more prominent among females. Those with A/T in rs1719153 were 56% less likely to develop RA compared with females with A/A; a similar protective effect was seen for females with the A/T+T/T genotype compared with those with A/A. The GTEx database revealed that patients carrying the T/T genotype had lower levels of CCL4 gene expression than those carrying the A/A genotype. These results indicate that the nucleotide T over the rs1719153 is associated with decreased CCL4 gene expression and decreased risk for RA.