Serum IL-33 level and IL-33 gene polymorphisms in Behçet’s disease

Decoding Behcet's Uveitis: an In-depth review of pathogenesis and therapeutic advances

Behcet's disease (BD) is a rare but globally distributed vasculitis that primarily affects populations in the Mediterranean and Asian regions. Behcet's uveitis (BU) is a common manifestation of BD, occurring in over two-thirds of the patients. BU is characterized by bilateral, chronic, recurrent, non-granulomatous uveitis in association with complications such as retinal ischemia and atrophy, optic atrophy, macular ischemia, macular edema, and further neovascular complications (vitreous hemorrhage, neovascular glaucoma). Although the etiology and pathogenesis of BU remain unclear, numerous studies reveal that genetic factors (such as HLA-B51), dysregulated immune responses of both the innate and adaptive immune systems, infections (such as streptococcus), and environmental factors (such as GDP) are all involved in its development. Innate immunity, including hyperactivity of neutrophils and γδT cells and elevated NK1/NK2 ratios, has been shown to play an essential role in this disease. Adaptive immune system disturbance, including homeostatic perturbations, Th1, Th17 overaction, and Treg cell dysfunction, is thought to be involved in BU pathogenesis. Treatment of BU requires a tailored approach based on the location, severity of inflammation, and systemic manifestations. The therapy aims to achieve rapid inflammation suppression, preservation of vision, and prevention of recurrence. Systemic corticosteroids combined with other immunosuppressive agents have been widely used to treat BU, and beneficial effects are observed in most patients. Recently, biologics have been shown to be effective in treating refractory BU cases. Novel therapeutic targets for treating BU include the LCK gene, Th17/Treg balance, JAK pathway inhibition, and cytokines such as IL-17 and RORγt. This article summarizes the recent studies on BU, especially in terms of pathogenesis, diagnostic criteria and classification, auxiliary examination, and treatment options. A better understanding of the significance of microbiome composition, genetic basis, and persistent immune mechanisms, as well as advancements in identifying new biomarkers and implementing objective quantitative detection of BU, may greatly contribute to improving the adequate management of BU patients.

Biological effects of IL-33/ST2 axis on oral diseases: autoimmune diseases and periodontal diseases

IL-33 is a relatively new member of the IL-1 cytokine family, which plays a unique role in autoimmune diseases, particularly some oral diseases dominated by immune factors. The IL-33/ST2 axis is the main pathway by which IL-33 signals affect downstream cells to produce an inflammatory response or tissue repair. As a newly discovered pro-inflammatory cytokine, IL-33 can participate in the pathogenesis of autoimmune oral diseases such as Sjogren's syndrome and Behcet's disease. Moreover, the IL-33/ST2 axis also recruits and activates mast cells in periodontitis, producing inflammatory chemokines and mediating gingival inflammation and alveolar bone destruction. Interestingly, the high expression of IL-33 in the alveolar bone, which exhibits anti-osteoclast effects under appropriate mechanical loading, also confirms its dual role of destruction and repair in an immune-mediated periodontal environment. This study reviewed the biological effects of IL-33 in autoimmune oral diseases, periodontitis and periodontal bone metabolism, and elaborated its potential role and impact as a disease enhancer or a repair factor.

Association of interleukin 33 gene polymorphisms with susceptibility and regulation of inflammatory mediators in Systemic lupus erythematosus patients

BACKGROUND

Studies have indicated the involvement of interleukin (IL)-33 in the pathogenesis of Systemic lupus erythematosus (SLE). This research intended to evaluate the association of IL33 gene rs1929992 and rs7044343 Single nucleotide polymorphisms (SNPs) with risk of SLE. In addition, the association between these SNPs and inflammatory cytokines was determined.

METHODS

In this study, 200 SLE cases and 200 healthy subjects were recruited. Using allelic discrimination Real-time PCR, IL33 gene rs1929992 and rs7044343 SNPs were genotyped. The mRNA expression levels of IL-1β, IL-6, IL-33, TNF-α were determined in the peripheral blood mononuclear cells (PBMCs). The serum levels of cytokines were also measured.

RESULTS

The G allele (OR = 1.57, CI: 1.18-2.08, P = 0.0017), GG genotype (OR = 2.52, CI: 1.33-4.77, P = 0.0043), and GA genotype (OR = 2.12, CI: 1.34-3.34, P = 0.0011) of rs1929992 SNP was significantly associated with an increased SLE risk. The C allele (OR = 1.44, CI: 1.08-1.90; P = 0.0105), CC genotype (OR = 2.07, CI: 1.15-3.71; P = 0.0146), and CT genotype (OR = 1.61, CI: 1.02-2.53, P = 0.0395) of rs7044343 was significantly associated with increased SLE risk. The PBMC mRNA expression and serum levels of IL-1β, IL-6, IL-33, TNF-α were significantly increased in the SLE patients compared to controls. However, there was no significant difference in the mRNA expression and serum levels of IL-1β, IL-6, IL-33, and TNF-α among the SLE patients with three genotypes for both rs1929992 and rs7044343 polymorphisms.

CONCLUSIONS

IL33 gene rs1929992 and rs7044343 SNPs are involved in SLE pathogenesis but they might not influence on the inflammatory pathway.

Alarmins in autoimmune diseases

Alarmins are endogenous, constitutively expressed, chemotacting and immune activating proteins or peptides released because of non-programmed cell death (i.e. infections, trauma, etc). They are considered endogenous damage-associated molecular patterns (DAMPs), able to induce a sterile inflammation. In the last years, several studies highlighted a possible role of different alarmins in the pathogenesis of various autoimmune and immune-mediated diseases. We reviewed the relevant literature about this topic, for about 160 articles. Particularly, we focused on systemic autoimmune diseases (systemic lupus erythematosus, rheumatoid arthritis, idiopathic inflammatory myopathies, ANCA-associated vasculitides, Behçet's disease) and cutaneous organ-specific autoimmune diseases (vitiligo, psoriasis, alopecia, pemphigo). Finally, we discussed about future perspectives and potential therapeutic implications of alarmins in autoimmune diseases. In fact, identification of receptors and downstream signal transducers of alarmins may lead to the identification of antagonistic inhibitors and agonists, with the capacity to modulate alarmins-related pathways and potential therapeutic applicability.

A prognostic model of non small cell lung cancer based on TCGA and ImmPort databases

Bioinformatics methods are used to construct an immune gene prognosis assessment model for patients with non-small cell lung cancer (NSCLC), and to screen biomarkers that affect the occurrence and prognosis of NSCLC. The transcriptomic data and clinicopathological data of NSCLC and cancer-adjacent normal tissues were downloaded from the Cancer Genome Atlas (TCGA) database and the immune-related genes were obtained from the IMMPORT database (http://www.immport.org/); then, the differentially expressed immune genes were screened out. Based on these genes, an immune gene prognosis model was constructed. The Cox proportional hazards regression model was used for univariate and multivariate analyses. Further, the correlations among the risk score, clinicopathological characteristics, tumor microenvironment, and the prognosis of NSCLC were analyzed. A total of 193 differentially expressed immune genes related to NSCLC were screened based on the "wilcox.test" in R language, and Cox single factor analysis showed that 19 differentially expressed immune genes were associated with the prognosis of NSCLC (P < 0.05). After including 19 differentially expressed immune genes with P < 0.05 into the Cox multivariate analysis, an immune gene prognosis model of NSCLC was constructed (it included 13 differentially expressed immune genes). Based on the risk score, the samples were divided into the high-risk and low-risk groups. The Kaplan–Meier survival curve results showed that the 5-year overall survival rate in the high-risk group was 32.4%, and the 5-year overall survival rate in the low-risk group was 53.7%. The receiver operating characteristic model curve confirmed that the prediction model had a certain accuracy (AUC = 0.673). After incorporating multiple variables into the Cox regression analysis, the results showed that the immune gene prognostic risk score was an independent predictor of the prognosis of NSCLC patients. There was a certain correlation between the risk score and degree of neutrophil infiltration in the tumor microenvironment. The NSCLC immune gene prognosis assessment model was constructed based on bioinformatics methods, and it can be used to calculate the prognostic risk score of NSCLC patients. Further, this model is expected to provide help for clinical judgment of the prognosis of NSCLC patients.

Serum IL-33 as a biomarker in different diseases: useful parameter or much need for clarification?

Interleukin-33 (IL-33), a member of the IL-1 family, is critically involved in the modulation of the activity of a diverse range of immunocompetent cells. Essential roles have been implicated in cardioprotection, in both innate and adaptive immune responses in mucosal organs, and in the maintenance of adipose tissue cells. Over the past 10 years, several studies evaluated the usability of IL-33 as a biomarker in diseases of inflammatory and noninflammatory origin. Our group is currently evaluating the predictive role of serum IL-33 in acute kidney injury (AKI). The aim of the article is to discuss selected studies on IL-33 in different diseases and its potential role as a biomarker molecule.

A single nucleotide polymorphism in the IL1RL1 gene is associated with Behcet's disease in a Chinese Han population

AIM

To explore the association of single nucleotide polymorphisms (SNPs) in the IL33/IL1RL1 gene region with the susceptibility to Behcet's disease (BD) in a Chinese Han population.

METHODS

A total of eight SNPs in the candidate gene region (rs11792633, rs7025417, rs10975519 and rs1048274 in IL33; rs2310220, rs12712142, rs13424006 and rs3821204 in IL1RL1) were genotyped in783 BD patients and 701 healthy controls by the Sequenom Mass Array iPLEX platform.

RESULTS

A statistically significant association was observed between IL1RL1 rs12712142 and BD patients. The frequency of IL1RL1 rs12712142 variant allele A was significantly lower in BD patients than that in controls (OR=0.8, 95%CI: 0.69-0.94, Pc=0.039); the genotype distribution (Pc=0.043) and additive and dominant genetic model analyses (OR=0.8, 95%CI: 0.69-0.94, Pc=0.040 and OR=0.72, 95%CI: 0.58-0.88, Pc=0.011) also indicated a strong association between rs12712142 and BD patients.

CONCLUSION

This is the first study to reveal the association between IL1RL1 rs12712142 variant allele A and the decreased risk of BD in the Chinese Han population, indicating a protective role of IL1RL1 in the pathogenesis of BD.

Increased serum level of interleukin-33 in Vogt-Koyanagi-Harada correlates with disease activity

OBJECTIVES

To measure the serum level of IL-33 in patients with Vogt-Koyanagi-Harada disease (VKH) and Behçet's uveitis (BU) in the Chinese Han population and investigate its associations with disease activity and clinical parameters.

METHODS

Serum was collected from 41 VKH patients (16 active and 25 inactive patients), 60 BU patients (24 active and 36 inactive patients), and 36 healthy controls. The serum level of IL-33 was measured using the enzyme-linked immunosorbent assay (ELISA) method. Demographic features, clinical manifestations, and intraocular inflammation activity scores (anterior chamber cells score, anterior chamber flare score, and vitreal haze score) were recorded.

RESULTS

The serum level of IL-33 significantly increased in all VKH patients, active VKH patients, and inactive VKH patients, as compared to healthy controls (p < 0.001, p < 0.001, and p = 0.002, respectively), and was higher in the active VKH than in the inactive VKH patients (p = 0.049). The serum level of IL-33 positively correlated with the anterior chamber cells score, vitreal haze score, and the annualized number of relapses in VKH patients (Rho = 0.359, p = 0.021; Rho = 0.344, p = 0.028; Rho = 0.537, p < 0.001, respectively). Serum IL-33 level was significantly associated with the annualized number of relapses in patients with BU (Rho = 0.361, p = 0.005).

CONCLUSION

Serum IL-33 level is significantly increased in VKH patients in the Chinese Han population. IL-33 level is in positive correlation with the activity and relapses of VKH. Increased IL-33 might contribute to the pathogenesis of VKH and serve as a potential biomarker for VKH disease.

A comprehensive in Silico analysis of the functional and structural impact of single nucleotide polymorphisms (SNPs) in the human IL-33 gene

Interleukin 33 (IL-33) is the latest member of the IL-1 cytokine family, which plays both pro - and anti-inflammatory functions. Numerous Single-nucleotide polymorphisms (SNPs) in the IL-33 gene have been recognized to be associated with a vast variety of inflammatory disorders. SNPs associated studies have become a crucial approach in uncovering the genetic background of human diseases. However, distinguishing the functional SNPs in a disease-related gene from a pool of both functional and neutral SNPs is a major challenge and needs multiple experiments of hundreds or thousands of SNPs in candidate genes. This study aimed to identify the possible deleterious SNPs in the IL-33 gene using bioinformatics predictive tools. The nonsynonymous SNPs (nsSNPs) were analyzed by SIFT, PolyPhen, PROVEAN, SNP&GO, MutPred, SNAP, PhD SNP, and I-Mutant tools. The Non-coding SNPs (ncSNPs) were also analyzed by SNPinfo and RegulomeDB tools. In conclusion, our in-silico analysis predicted 5 nsSNPs and 22 ncSNPs as potential candidates in the IL-33 gene for future genetic association studies.

IL-33 Gene Polymorphisms as Potential Biomarkers of Disease Susceptibility and Response to TNF Inhibitors in Rheumatoid Arthritis, Ankylosing Spondylitis, and Psoriatic Arthritis Patients

Objective

Rheumatoid arthritis (RA), ankylosing spondylitis (AS), and psoriatic arthritis (PsA) belong to inflammatory rheumatic diseases, the group of conditions of unknown etiology. However, a strong genetic component in their pathogenesis has been well established. A dysregulation of cytokine networks plays an important role in the development of inflammatory arthritis. Interleukin 33 (IL-33) is a recently identified member of the IL-1 family. To date, the significance of IL-33 in inflammatory arthritis has been poorly studied. This research aimed to investigate the potential of IL-33 gene polymorphisms to serve as biomarkers for disease susceptibility and TNF inhibitor response in RA, AS, and PsA patients.

Materials and Methods

In total, 735 patients diagnosed with RA, AS, and PsA and 229 healthy individuals were enrolled in the study. Genotyping for three single nucleotide polymorphisms (SNPs) within the IL-33 gene, namely, rs16924159 (A/G), rs10975519 (T/C), and rs7044343 (C/T), was performed using polymerase chain reaction amplification employing LightSNiP assays.

Results

In the present study, the IL-33 rs10975519 CC genotype was associated with a decreased risk of developing RA in females, while the IL-33 rs16924159 polymorphism was associated with the efficacy of anti-TNF therapy and clinical parameters for RA and AS patients. The IL-33 rs16924159 AA genotype correlated with higher disease activity and worse clinical outcomes in RA patients treated with TNF inhibitors, and AS patients carrying the IL-33 rs16924159 AA genotype had higher disease activity and a worse response to anti-TNF therapy. That indicates a deleterious role of the IL-33 rs16924159 AA genotype in the context of RA, as well as AS.

Conclusions

The obtained results suggest that IL-33 gene polymorphisms might be potential candidate biomarkers of disease susceptibility and anti-TNF treatment response in patients with inflammatory rheumatic diseases.

Genetic Association of Interleukin 33/ST2 Polymorphisms With Behcet's Uveitis

Interleukin (IL)33, a member of the IL1 superfamily, functions as a nuclear factor and mediates biological effects by interacting with the ST2 receptor. Recent studies have described IL33 as an emerging pro-inflammatory cytokine in the immune system, and IL33/ST2 gene polymorphisms have been implicated in the pathogenesis of various immune diseases. However, the underlying mechanisms of IL33/ST2 in Behcet's disease (BD) remain to be defined. Here, we investigated the association between IL33/ST2 gene polymorphisms and BD in 585 BD uveitis (BDU) patients and 834 healthy controls using Agena MassARRAY iPLEX platform. We found that rs3821204 was associated with the development of BDU. Moreover, the frequency of rs2210463 G allele was lower in patients with genital involvement. Association analysis revealed a much greater genetic difference between complete-type and incomplete-type BD groups, including three SNPs (rs7044343, rs1048274, and rs2210463). Our findings suggest that IL33/ST2 gene polymorphisms are involved in the pathogenesis of BDU. Different genetic backgrounds may exist in complete-type and incomplete-type BD patients.

The Role of the IL-33/ST2 Immune Pathway in Autoimmunity: New Insights and Perspectives

Interleukin (IL)-33, a member of IL-1 cytokine family, is produced by various immune cells and acts as an alarm to alert the immune system after epithelial or endothelial cell damage during cell necrosis, infection, stress, and trauma. The biological functions of IL-33 largely depend on its ligation to the corresponding receptor, suppression of tumorigenicity 2 (ST2). The pathogenic roles of this cytokine have been implicated in several disorders, including allergic disease, cardiovascular disease, autoimmune disease, infectious disease, and cancers. However, alerted levels of IL-33 may result in either disease amelioration or progression. Genetic variations of IL33 gene may confer protective or susceptibility risk in the onset of autoimmune diseases. The purpose of this review is to discuss the involvement of IL-33 and ST2 in the pathogenesis of a variety of autoimmune disorders, such as autoimmune rheumatic, neurodegenerative, and endocrine diseases.

Endothelin-1 Serum Concentration in Pediatric Chronic Idiopathic Uveitis

Purpose

The aim of our study was to determine endothelin-1 (ET-1) concentration in chronic idiopathic uveitis in children and adolescents depending on anatomical location and grade of inflammation.

Methods

The cross-sectional study was conducted among 17 patients with chronic idiopathic uveitis and 22 healthy controls. Concentration of ET-1 in serum was determined using a commercially available ELISA kit. The concentration of C reactive protein (CRP) in serum was determined by immunoturbidimetric method using CRP4 reagent kit (Roche Diagnostics GmbH, Mannheim, Germany).

Results

Statistically significant difference between ET-1 concentration in patients with chronic idiopathic uveitis and controls was found 1.33 (1.22; 1.48) vs 1.93 (1.1; 3.11), p = 0.008). No correlations were found between ET-1 concentration and age, either in chronic idiopathic uveitis patients or controls. Nine out of 17 patients presented with anterior uveitis, 5 with posterior and 3 with panuveitis. There were no differences in ET-1 concentration between anterior, posterior and panuveitis (p = 0.634), and in terms of grade of inflammation.

Conclusion

ET-1 expression is disturbed in pediatric chronic idiopathic uveitis irrespective of the anatomical location and grade of inflammation. Lower expression of ET-1 plays a crucial role in disturbed vascular tone control and can result in permanent visual impairment in chronic non-infectious uveitis.

The Functional Roles of IL-33/ST2 Axis in Ocular Diseases

Interleukin-33 (IL-33), an important member of the IL-1 family, plays a pivotal role in regulating immune responses via combining with its receptor suppression of tumorigenicity 2 (ST2). We have already known IL-33/ST2 axis participates in the pathogenesis of various diseases, including liver diseases, renal diseases, and neurological diseases. Recently, emerging studies are indicating that IL-33/ST2 is also involved in a wide range of ocular diseases, such as allergic eye disease, keratitis and corneal regeneration, dry eye disease, uveitis, vitreoretinal diseases, and neuromyelitis optica spectrum disorder. In this review, we will summarize and discuss the current understanding about the functional roles of IL-33/ST2 in eyes, with an attempt to explore the possible study perspectives and therapeutic alternatives in the future.

Association between IL-33 Gene Polymorphism (Rs7044343) and Risk of Allergic Rhinitis

BACKGROUND

Allergic rhinitis (AR) is a T helper type 2 (Th2)-mediated upper airways disease in which genetics factors including cytokine genes play a prominent role. Interleukin-33 (IL-33) is a major cytokine for naive T cells polarization into Th2 phenotype as well as enhances the secretion of Th2 cytokines. The aim of the present study was to investigate the relationship between IL-33 single nucleotide polymorphisms (SNPs) and IL-33 serum level with Allergic rhinitis.

METHODS

Blood samples were collected from 130 AR patients and 130 healthy individuals. SNPs (rs7044343 C > T, rs1929992 A > G, rs12551256 A > G) of IL-33 gene were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Serum level of IL-33 was measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Statistical analysis showed that the TT genotype (OR = 1.996, CI: 1.168-3.412, P = .01), as well as the T allele (OR = 0.675, CI: 0.476-0.957, P = .02) of rs7044343 C > T were significantly associated with reduced risk of AR. In addition, individuals carrying the TT genotype were associated with lower levels of IL-33 compared to subjects with CC and CT genotypes; however, these differences were not statistically significant. No association was found between rs1929992 and rs12551256 variants and risk of AR, but the GG genotype from rs1929992 A > G was associated with increased serum levels of IL-33 in control group (p = .01). Furthermore, serum IL-33 levels were not significantly different between AR patients and healthy controls (p > .05).

CONCLUSION

Our results suggest that the TT genotype of rs7044343 C > T may act as a protective agent against allergic rhinitis.

Association between ADRB2, IL33, and IL2RB gene polymorphisms and lung cancer risk in a Chinese Han population

PURPOSE

This study aimed to explore the associations between polymorphisms of a very important pharmacogene, ADRB2, two inflammation-related genes, IL33 and IL2RB, and the risk of lung cancer.

METHODS

Six polymorphisms of ADRB2, IL33, and IL2RB were genotyped in 300 lung cancer patients and 300 healthy controls using MassARRAY. The relationship between genotypes and lung cancer risk was evaluated using chi-square tests.

RESULTS

The minor allele of rs1042711 was a risk allele for lung cancer, whereas the minor alleles of rs7025417 and rs5756523 had protective effects against lung cancer (p＜0.05). The CT genotype of rs1042711 and the GT genotype of rs1560642 were associated with increased risk of lung cancer, whereas the CC and AA genotypes of rs7025417 and the CT and CC genotypes of rs5756523 were associated with decreased disease risk (p < 0.05). Genetic model analysis shows that rs1042711 and rs1560642 were associated with increased risk of lung cancer; whereas rs7025417, rs5756523, and rs2284033 were associated with decreased disease risk (p < 0.05). Stratification analysis showed that rs1042711 and rs1560642 were associated with increased risk of lung cancer in nonsmokers and smokers, respectively, whereas rs7025417 and rs5756523 were associated with decreased disease risk in both subgroups (p＜0.05).

CONCLUSION

Our results shed new light on the association between polymorphisms of ADRB2, IL33, and IL2RB and the risk of lung cancer.

Decreased circulating interleukin-33 concentration in Helicobacter pylori-infected patients with peptic ulcer: Evaluation of its association with a cytokine gene polymorphism, gender of patients and bacterial virulence factor CagA

IL-33 has powerful immunoregulatory activities such as reinforcement of Th2 cell responses. The aim was to assess the circulating IL-33 levels and IL-33 rs1929992 polymorphism in H. pylori-infected peptic ulcer (PU) patients and asymptomatic (AS) subjects. Blood samples were obtained from 100 PU patients, 100 AS subjects and 100 uninfected individuals. Circulating IL-33 levels were detected by ELISA. After DNA extraction, the IL-33 rs1929992 polymorphism was determined using PCR-RFLP method. Serum IL-33 quantities were significantly lower in PU patients compared with AS and uninfected groups. IL-33 levels were higher in AS subjects compared with uninfected group. In PU, AS and uninfected groups, IL-33 levels were significantly higher in women than men. In PU and AS groups, the CagA⁺H. pylori-infected subjects exhibit higher IL-33 levels compared with carriers of CagA^-H. pylori strains. In PU patients, the frequency of genotype GG and allele G at IL-33 rs1929992 was significantly higher compared with all healthy subjects (AS + uninfected groups). The presence of genotypes GG and AG, and allele G in rs1929992 conferred greater risk for PU. In whole H. pylori-infected population (PU + AS groups), IL-33 levels in individuals with genotype AA or allele A at rs1929992 were higher than subjects with GG genotype or allele G. The reduced IL-33 production could contribute to the PU development during H. pylori infection. The IL-33 levels may be affected by individual gender, rs1929992 polymorphism, and the CagA status of bacteria. The rs1929992-related GG genotype and G allele may be associated with PU development.

Interaction between IL-33 Gene Polymorphisms and Current Smoking with Susceptibility to Systemic Lupus Erythematosus

Aims

This study is aimed at exploring the relation between IL-33 single-nucleotide polymorphisms (SNPs) and the risk of systemic lupus erythematosus (SLE).

Methods

SNPStats (online software) was used to test the Hardy-Weinberg equilibrium in controls. Generalized multifactor dimensionality reduction (GMDR) was adopted to screen the preferable interaction between IL-33 SNPs and current smoking.

Results

Logistic regression analysis based on the fundamental data of age, gender, BMI, current smoking, and alcohol drinking showed that both rs1929992-G and rs1891385-C alleles were correlated with an increasing risk of SLE, the ORs (95% CI) of which were 1.62 (1.21-2.05) and 1.64 (1.22-2.10), respectively. One two-locus model (rs1929992×current smoking) had a testing accuracy of 60.11% (P = 0.0010). Through an overall multidimensional model, optimum cross-validation consistency was obtained. The analysis indicated that current smoking status influenced the SLE risk depending on the genotypes at rs1929992. Pairwise LD analysis indicated that haplotype rs1929992G-rs7044343T was statistically related to the elevating risk of SLE (P < 0.05). Those subjects with the G-T haplotype had a higher SLE risk than those with other haplotypes, after correction with factors, including gender, alcohol drinking, age, BMI, and current smoking.

Conclusions

The rs1929992-G and rs1891385-C allele, interaction between the rs1929992 gene and current smoking, and haplotype rs1929992G-rs7044343T were all risk factors of SLE.

Interleukin-33 gene expression and rs1342326 polymorphism in Behçet's disease

OBJECTIVE

Behçet's disease (BD) is a chronic multi-factorial inflammatory disease with the important role of genetic in activation of its inflammatory response. Interleukin (IL)-33 is a member of the IL-1 family of cytokines that affects innate and adaptive immune systems to promote inflammatory responses. In the current study, we investigated the association of IL-33 gene rs1342326 polymorphism and expression levels of this gene in peripheral blood mononuclear cells (PBMCs) with the susceptibility to BD in Azari population of Iran.

METHODS

We recruited 44 patients with BD and 61 age and sex-matched healthy controls in this cross-sectional study. The existence of rs1342326 T/G IL-33 gene single nucleotide polymorphism was investigated using Tetra-Amplification Refractory Mutation System (Tetra-ARMS)-PCR. Allele and genotype distributions were evaluated among groups using chi-square or Fisher's test. Moreover, the mRNA levels of IL-33 in PBMCs were assessed through the Real-time PCR.

RESULTS

Patients with BD exhibited a significantly higher prevalence of the T/G genotype of rs1342326 polymorphism compared with the control group. Moreover, the expression level of IL-33 in PBMCs was significantly higher in the BD group compared to the healthy controls. Interestingly, the rs1342326 T/G polymorphism was associated with higher IL-33 expression in patients with BD. There was no association between the clinical manifestation of BD and disease activity with rs1342326 polymorphism and IL-33 expression.

CONCLUSIONS

Our study implies that rs1342326 T/G polymorphism of the IL-33 gene may contribute to the genetic susceptibility to BD in part through regulation of the IL-33 expression.

Behçet's disease: An immunogenetic perspective

Behçet's disease (BD) is a chronic and rare multisystemic disorder defined by autoimmunity and inflammatory characteristics, manifested by ocular lesions, recurrent genital and oral ulcers, skin symptoms and arthritis as well as neurological, intestinal, and vascular involvement. Despite the unknown cause of BD, there is some strong documentation for immunological, genetic, environmental, and infectious factors playing a role in the pathogenesis of BD. While the nature of the genetic variants remains unidentified, many genetic risk factors are considered to contribute to BD susceptibility. Along with human leukocyte antigen gene encoding B*51 (HLA-B*51) and areas including the major histocompatibility complex class I, genome-wide association studies have recognized numerous other BD susceptibility genes including those encoding interleukin (IL)-10, IL-12 receptor β 2 (IL-12RB2), IL-23 receptor (IL-23R), C-C chemokine receptor 1 gene, signal transducer and activator of transcription 4 (STAT4), endoplasmic reticulum aminopeptidase (ERAP1), and genes encoding killer cell lectin-like receptor family members (KLRC4-KLRK1). It is believed that BD could be considered as a disorder lying in between autoimmune and autoinflammatory syndromes. The positive responses to classical immunosuppressive agents like azathioprine and cyclosporine and involvement of autoantigens in the initiation of the disorder are the main BD features that reflect the autoimmune nature of the disorder. In this review, we address recent findings on the role of common cytokines, antibodies and immunogenetic factors in BD.

Genetic Diversity of Bovine Major Histocompatibility Complex Class II DRB3 locus in cattle breeds from Asia compared to those from Africa and America

Genetic polymorphisms and diversity of BoLA-DRB3.2 are essential because of DRB3 gene's function in innate immunity and its association with infectious diseases resistance or tolerance in cattle. The present study was aimed at assessing the level of genetic diversity of DRB3 in the exon 2 (BoLA-DRB3.2) region in African, American and Asian cattle breeds. Amplification of exon 2 in 174 cattle revealed 15 haplotypes. The breeds with the highest number of haplotypes were Brangus (10), Sokoto Gudali (10) and Dajal (9), while the lowest number of haplotypes were found in Holstein and Sahiwal with 4 haplotypes each. Medium Joining network obtained from haplotypic data showed that all haplotypes condensed around a centric area and each sequence (except in H-3, H-51 and H-106) representing almost a specific haplotype. The BoLA-DRB3.2 sequence analyses revealed a non-significant higher rate of non-synonymous (dN) compared to synonymous substitutions (dS). The ratio of dN/dS substitution across the breeds were observed to be greater than one suggesting that variation at the antigen-binding sites is under positive selection; thus increasing the chances of these breeds to respond to wide array of pathogenic attacks. An analysis of molecular variance revealed that 94.01 and 5.99% of the genetic variation was attributable to differences within and among populations, respectively. Generally, results obtained suggest that within breed genetic variation across breeds is higher than between breeds. This genetic information will be important for investigating the relationship between BoLADRB3.2 and diseases in various cattle breeds studied with attendant implication on designing breeding programs that will aim at selecting individual cattle that carry resistant alleles.

Investigating the role of IL-33 in the pathogenesis of Behçet's Disease

OBJECTIVES

Behçet's disease (BD) is an inflammatory disease, characterized by oral aphthous lesions, recurrent uveitis, skin lesions, and genital ulcerations. Increased release of several cytokines may play a role in the inflammatory stages of BD. IL-33, a member of the IL-1 cytokine superfamily, plays an important role in inflammation. We analyzed serum IL-33 concentration in BD patients to assess its possible role in the pathophysiology of this disease.

METHODS

The study included 54 BD patients, 31 with active BD and 23 with inactive BD as well as 18 matched healthy controls. Serum IL-33 levels were measured using an enzyme-linked immunosorbent assay (ELISA).

RESULTS

The mean serum IL-33 levels were 4.84 ± 2.81 pg/ml in the BD patients (6.16 ± 2.94 pg/ml in the active stage and 2.86 ± 0.54 pg/ml in the inactive stage) and 2.88 ± 0.42 pg/ml in the healthy controls. Serum IL-33 levels were significantly higher in patients with BD compared with the healthy controls (p < 0.01). In active Behçet patients with arthritis the mean serum IL-33 level was higher but this finding was not statistically significant (p = 0.122).

CONCLUSION

IL-33 may play a significant role of in the pathogenesis of BD.

Interleukin-26 is overexpressed in Behçet's disease and enhances Th17 related -cytokines

Behçet's disease (BD) is a multi-systemic inflammatory disorder characterized by the "triple symptom complex". Several pro-inflammatory cytokines, mainly derived from the immune Th17 axis, seem to be involved in different pathogenic pathways leading to development of the clinical manifestations. Here, we have analyzed the expression and role of IL-26 in active BD patients, an inflammatory disorder characterized by bronchoalveolar lavage fluid (BAL) and cerebrospinal fluid (CSF) inflammation. On this basis, the primary aim of our work was to study IL-26 levels in serum, BAL CSF) from active BD patients. Samples were collected from 95 BD patients (55 patients were in active stage) and 50 healthy controls (HC). They were investigated with ELISA for estimation of cytokines levels. Serum concentration of IL-26 resulted higher in both active [4.80±1.32] and inactive [2.77±1.026] BD than HC [0.31±0.14ng/ml; p<0.0001]. Level of IL-26 was associated with the BD clinical severity score from moderate to severe (P<0.0001). IL-26 was highly expressed in CSF [10.80±2.05ng/ml] and in BAL [12.89±3.03ng/ml] fluid from BD patients comparatively to their respective controls. IL-26 levels in CSF and in BAL fluid showed positive correlations with IL-17 level and an inversely correlation with IL-37. Interestingly, IL-26-stimulated CD4⁺ T cells and monocytes promote the generation of Th17 (IL-17A, IL-23) and suppress Treg (IL-10, TGF-β) cytokines. Our findings may suggest a signature of IL-26 probably responsible for the inflammatory process to correlate positively with Th17 cytokines and inversely with Treg mediators. This evidence could contribute to improve the knowledge regarding the role of IL-26 in BD severity. For the first time, IL-26 expression is demonstrated in BAL and CSF, supporting a role for this cytokine in the pathogenesis of BD. IL-26 thereby appears as a novel proinflammatory cytokine favoring the generation of Th17 cytokines.

Association of interleukin-33 gene polymorphisms with susceptibility to late onset Alzheimer's disease: a meta-analysis

The association between interleukin-33 (IL-33) gene polymorphisms and late onset Alzheimer's disease (LOAD) remains controversial in previous studies. Thus, a meta-analysis was conducted to assess the association between the IL-33 polymorphisms (rs11792633 and rs7044343) and LOAD susceptibility. Crude odds ratio (OR) and 95% confidence interval (CI) were used to investigate the relationship strength. Sensitivity analysis was performed, and publication bias was estimated by the Begg's and Egger's tests. Overall, six independent studies involving 2,589 patients and 8,414 control samples met our inclusion criteria and were included in this meta-analysis. The results showed that IL-33 rs11792633 polymorphism had statistically significant correlation with a decreased risk of LOAD in heterozygous comparison model (OR =0.64, 95% CI =0.48-0.83), homozygote comparison model (OR =0.83, 95% CI =0.74-0.93), dominant model (OR =0.78, 95% CI =0.67-0.91), recessive model (OR =0.70, 95% CI =0.59-0.84), and allelic model (OR =0.79, 95% CI =0.69-0.91), which were also validated by stratified subgroup analysis. Additionally, there was an apparent association between the IL-33 rs7044343 variant and LOAD risk under four genetic models for overall population (heterozygous comparison model: OR =0.75, 95% CI =0.63-0.89; dominant model: OR =0.83, 95% CI =0.70-0.98; recessive model: OR =0.80, 95% CI =0.68-0.94; allelic model: OR =0.86, 95% CI =0.79-0.94) as well as Caucasian subgroup. In summary, our meta-analysis implicated that IL-33 gene polymorphisms rs11792633 and rs7044343 were significantly associated with the susceptibility of LOAD.

Association between IL-33 Gene Polymorphisms (rs1929992, rs7044343) and Systemic Lupus Erythematosus in a Chinese Han Population

OBJECTIVE

Interleukin-33 (IL-33) is a member of the IL-1 family, and previous studies found the single-nucleotide polymorphisms (SNPs) in the IL-33 gene was related to susceptibility to autoimmune diseases, including rheumatoid arthritis, ankylosing spondylitis and Behcet's disease. To date, no study has discussed the potential association between IL-33 gene polymorphisms and systemic lupus erythematosus (SLE).

METHODS

We conducted a case-control study including 371 SLE patients and 408 healthy controls to investigate the correlation between the SNPs of IL-33 gene (rs1929992, rs7044343) and SLE in a Chinese Han population.

RESULTS

There was significantly lower expression of allele G for rs1929992 in SLE patients than that in controls (G versus A, P = 0.012, OR = 1.310, 95% CI: 1.060-1.624 after adjustment with sex). Similarly, genotype GG was associated with the susceptibility to SLE as compared with the AA genotype (P = 0.017, OR = 1.714, 95% CI: 1.101-2.669 after adjustment with sex). We also found statistical significance in the dominant model (GG+GA versus AA, P = 0.017, OR = 1.481, 95% CI: 1.074-2.044 after adjustment with sex). However, we found no strong evidence for the association of IL-33 rs7044343 polymorphism with SLE. Moreover, association studies were performed on the relationship between the IL-33 gene polymorphisms and lupus nephritis as well as nine clinical features of SLE, but there was no significant association regarding the distribution of allele and genotype frequencies between SLE patients positive and negative for the presence of sub-phenotypes.

CONCLUSION

Our findings indicate that IL-33 rs1929992 polymorphism may be a potential biomarker for susceptibility to SLE.

The IL-33 gene is related to increased susceptibility to systemic sclerosis

Systemic sclerosis (SSc) is a chronic inflammatory disease characterized by widespread fibrosis of the skin and several visceral organs. The pro-fibrotic potential of interleukin (IL)-33 has been demonstrated by in both in vitro and in vivo settings; moreover, increased level of IL-33 has also been reported in patients with SSc. Therefore, the aim of the present study was to detect the potential association of IL-33 gene polymorphisms on the susceptibility of SSc. A total of 300 SSc patients and 280 healthy controls (HC) were enrolled in this multicentric preliminary candidate gene study. DNA samples were harvested using an appropriate commercial DNA isolation kit. Four single nucleotide polymorphisms (SNPs) of IL-33 gene (rs7044343, rs1157505, rs11792633 and rs1929992) were genotyped using the appropriate commercial primer/probe sets on real-time PCR. There was no significant difference in terms of the allelic distributions and minor allele frequencies of evaluated four IL-33 polymorphisms between the SSc and HC groups (P > 0.05 for all). Moreover, the genotypic distributions of rs1157505, rs11792633 and rs1929992 polymorphisms were not significantly different (P > 0.05 for all). However, CC genotype of rs7044343 SNP was significantly higher in the SSc group compared to the HC group (P = 0.013, OR 1.75, 95 % CI 1.12-2.72). This preliminary candidate gene study demonstrates that rs7044343 polymorphism of IL-33 gene is associated with the susceptibility to the SSc in Turkish population. It may be suggested that IL-33 gene may be a candidate gene to research in SSc.

Lack of genetic diversity across diverse immune genes in an endangered mammal, the Tasmanian devil (Sarcophilus harrisii)

The Tasmanian devil (Sarcophilus harrisii) is threatened with extinction due to the spread of devil facial tumour disease. Polymorphisms in immune genes can provide adaptive potential to resist diseases. Previous studies in diversity at immune loci in wild species have almost exclusively focused on genes of the major histocompatibility complex (MHC); however, these genes only account for a fraction of immune gene diversity. Devils lack diversity at functionally important immunity loci, including MHC and Toll-like receptor genes. Whether there are polymorphisms at devil immune genes outside these two families is unknown. Here, we identify polymorphisms in a wide range of key immune genes, and develop assays to type single nucleotide polymorphisms (SNPs) within a subset of these genes. A total of 167 immune genes were examined, including cytokines, chemokines and natural killer cell receptors. Using genome-level data from ten devils, SNPs within coding regions, introns and 10 kb flanking genes of interest were identified. We found low polymorphism across 167 immune genes examined bioinformatically using whole-genome data. From this data, we developed long amplicon assays to target nine genes. These amplicons were sequenced in 29-220 devils and found to contain 78 SNPs, including eight SNPS within exons. Despite the extreme paucity of genetic diversity within these genes, signatures of balancing selection were exhibited by one chemokine gene, suggesting that remaining diversity may hold adaptive potential. The low functional diversity may leave devils highly vulnerable to infectious disease, and therefore, monitoring and preserving remaining diversity will be critical for the long-term management of this species. Examining genetic variation in diverse immune genes should be a priority for threatened wildlife species. This study can act as a model for broad-scale immunogenetic diversity analysis in threatened species.