IL-1 cluster gene polymorphisms in Turkish patients with Behçet’s disease

Interleukin-1 gene (IL-1) polymorphism in patients with Behçet’s Disease, and its relationship with disease manifestations

Objective

The objective of this study was to investigate whether interleukin-1 (IL-1) gene polymorphisms are associated with susceptibility to Behçet’s disease (BD) and clinical manifestations of the disease.

Methods

In this cross-sectional study, we enrolled 110 patients with BD and age-and gender-matched 120 healthy controls. Five polymorphic regions of the IL-1 gene including rs 1800587 (IL1A-889 C/T), rs 2234650 (IL1R1), rs 16944 (IL1B-511 C/T), rs 315952 (IL1RN), and rs1143634 (IL1B-3954 C/T) were analyzed by using the real-time polymerase chain reaction system. Allele frequencies and genotypes were compared between groups. p ≤ 0.05 was accepted as statistically significant.

Results

The mean age of the patients with BD was 41 ± 12.4 years. The two groups were similar in terms of the age and gender distribution. The vast majority of BD patients had mucocutaneous involvement. The mean disease duration was 83.7 ± 67.8 months among the patients. The frequencies of each polymorphism in the IL-1 gene were similar between patients with BD and healthy controls.

Conclusion

The frequencies of variable IL-1 gene polymorphisms were similar between patients with BD and healthy controls.

Association between IL1B -511C/T polymorphism and Behçet's disease: a meta-analysis

Background

Many studies have investigated the relationship between the interleukin-1β gene (IL1B) −511C/T polymorphism and the risk of Behçet’s disease (BD); however, the conclusions remain controversial.

Methods

In this study, we systemically retrieved relevant studies from the Chinese Biomedicine Database, China National Knowledge Infrastructure, Embase, Cochrane Library, and PubMed databases. We then calculated the odds ratios (ORs) and 95% confidence intervals (CIs) using the meta-package Stata version 12.0.

Results

The IL1B −511C/T polymorphism was not related to BD susceptibility using any of the tested models (C vs T: OR = 1.20, 95% CI = 0.97–1.49; CC vs TT: OR = 1.27, 95% CI = 0.95–1.70; CT vs TT: OR = 1.03, 95% CI = 0.781.36; dominant model: OR = 1.12, 95% CI = 0.87–1.46; recessive model: OR = 1.27, 95% CI = 0.89–1.82). Similarly, subgroup analysis including studies consistent with the Hardy–Weinberg equilibrium revealed no association between the IL1B polymorphism and BD susceptibility.

Conclusion

This meta-analysis indicates that the IL1B −511C/T polymorphism is unlikely to affect the risk of BD; however, further large-scale, carefully designed studies are needed to verify these results.

The role of the inflammasomes in the pathogenesis of uveitis

Uveitis is a diverse group of sight-threatening intraocular inflammatory diseases usually causing eye redness, pain, blurred vision, and sometimes blindness. Although the exact pathogenesis of uveitis is not yet clear, accumulating evidences have shown that an imbalanced regulation of immune responses caused by a combination of genetic and environmental factors are implicated in the pathogenesis of this disease. As critical regulators of inflammation, inflammasomes have been assumed to play a role in the pathogenesis of uveitis. Recent studies have reported the association between a number of genetic variants in inflammasome related genes (such as NLRP3, NLRP1, NLRC4 and AIM2) with increased risk to uveitis. Mounting evidence have shown an aberrant activation of the NLRP3 inflammasome in both uveitis patients and murine models of uveitis. Some studies explored the intervention of uveitis via modulating inflammasome activity in the eye. This review aims at summarizing the main findings of these studies, proposing the possible mechanism whereby inflammasomes affect the susceptibility to develop uveitis, and giving a perspective for future studies, which may further improve our understanding about the role of inflammasomes and related cytokines in the pathogenesis of uveitis, and may hopefully lead to new therapeutics by targeting inflammasomes.

Lack of Association between Interleukin-1β Gene Polymorphism (rs16944) and Chronic Periodontitis: From a Case-Control Studies to an Updated Meta-Analysis

Background

Interleukin-1β (IL-1β) plays an important role as a mediator of various inflammatory responses in chronic periodontitis. Several studies have investigated the potential relationship between IL-1β polymorphism (rs16944) and susceptibility to chronic periodontitis; inflammatory process is involved, but conclusions is still controversial.

Objective

The aim of this study was to determine whether the IL-1β polymorphism (rs16944) is associated with susceptibility to chronic periodontitis.

Material and Methods

For the case-control study, 51 patients with chronic periodontitis and 33 healthy control patients were recruited in the study. Genotyping was conducted by direct sequencing. SNPStats and SPSS 18.0 were used for the analysis of genetic data and to evaluate odds ratios, 95% confidence intervals, and P values; logistic regression models were used. And to perform meta-analysis, studies about IL-1β polymorphism (rs16944) and chronic periodontitis were searched in PubMed, Embase, Google Scholar, and Korean Studies Information Service System (KISS) electronic databases until July 2017.

Results

In our case-control study, no significant relationship was revealed between IL-1β polymorphism (rs16944) and chronic periodontitis (P > 0.05 in each model). When combined with the previous studies in the meta-analysis, the result was not associated with chronic periodontitis in any of the models (CC vs. CT + TT: OR = 0.97, 95% CI = 0.762–1.246; CC + CT vs. TT: OR = 0.90, 95% CI = 0.658–1.232; and C vs. T: OR = 0.93, 95% CI = 0.774–1.128). The subgroup analysis stratified by ethnicity showed a weak association between the IL-1β polymorphism (rs16944) and chronic periodontitis in the Caucasian population (recessive model, OR = 1.34, 95% CI = 1.017–1.758, P = 0.037).

Conclusion

Evidences from a case-control study and the meta-analysis suggest that IL-1β polymorphism (rs16944) is not associated with susceptibility to chronic periodontitis.

Erythema nodosum in an adolescent patient with cryopyrin-associated periodic syndrome

Cryopyrin-associated periodic syndrome (CAPS) is a monogenetic auto-inflammatory disorder with systemic manifestations. Innate immune system aberrance is seen in both CAPS and erythema nodosum and this case may point to a previously unknown association. In pediatric patients with EN and systemic features, the possibility of underlying CAPS should be considered.

Investigation of the role of interleukin-1 receptor antagonist VNTR variant on the Behçet's disease

Objective

Behçet's disease (BD), a chronic multisystem inflammatory disorder, is mainly characterized by relapsing periods of a wide range of clinical symptoms. Several cytokine genes may play important roles in the pathogenesis of BD. Therefore, interleukin-1 receptor antagonist (IL-1Ra) gene 86bp variable number tandem repeat (VNTR) variant was investigated in patients with BD in a Turkish population.

Methods

One hundred nine patients (60 females, 49 males; the mean age±standard deviation [SD] was 36.56±9.571 years) with BD and one hundred healthy individuals (54 females, 46 males; the mean age±SD was 36.64±2.294 years) were examined in the study. For genotyping, polymerase chain reaction-restriction fragment length polymorphism analysis was employed. Data were analyzed using Statistical Package for Social Sciences (SPSS) 22.0 (IBM Corp.; Armonk, NY, USA) (p<0.05).

Results

The genotype distribution and allele frequencies of the IL-1Ra VNTR variant did not differ significantly between the patients and the controls (p>0.05). The frequency of the a1/a1, a1/a2 genotypes and a1, a2 alleles were the most common both in patients and healthy controls (p=0.37, p=0.26, and p=0.53, respectively). Also, no statistically significant difference was found between the IL-1Ra VNTR variant genotypes and clinical characteristics (p>0.05).

Conclusion

The results of this study do not support an association between the IL-1Ra VNTR variant and the risk of BD in a Turkish population. However, further studies of this variant with larger sample sizes and different ethnicities are required for confirmation.

Genetic analysis of innate immunity in Behcet's disease identifies an association with IL-37 and IL-18RAP

Interleukin-1 (IL-1) and the IL-1 receptor (IL-1R) family play an important role in the pathogenesis of inflammatory diseases. This study aimed to investigate the association between single nucleotide polymorphisms (SNP) of IL-1 and IL-1R family genes with Vogt-Koyanagi-Harada (VKH) and Behcet’s disease (BD) in Han Chinese. The case-control study was divided into two stages and included 419 VKH cases, 1063 BD cases and 1872 healthy controls. The MassARRAY platform (Sequenom), iPLEX Gold Assay and TaqMan SNP assays were used to score genotypes of 24 SNPs. The expression of IL-37 and IL-18Rap was measured by ELISA and real-time PCR in genotyped healthy individuals. A significantly lower frequency of the AG genotype, and a higher frequency of the GG genotype and G allele of IL-37/rs3811047 were observed in BD as compared to controls. AA genotype and A allele frequency of IL-18RAP/rs2058660 was significantly decreased in BD as compared to controls. Functional studies performed in healthy controls showed that rs3811047 AG genotype carriers had a higher IL-37 gene expression in peripheral blood mononuclear cells (PBMCs) than GG carriers. GG carriers showed a higher cytokine expression as compared to AG carriers. No association was detected between the tested SNPs and VKH.

The potential of genetically guided treatment in Behçet's disease

Continuous identification of specific targets and candidate genes together with novel approaches offers new promises for the future of gene therapy design in Behçet's disease (BD). Personalized medicine based on pharmacogenomics is being developed at the clinical stage to improve treatment response. Screening the whole gene and regulatory regions is important when searching for novel variants associated with such complex diseases. Different host genetic factors play significant roles in susceptibility to BD. Thus, identifying these genes responsible for susceptibility and resistance to BD may offer a notable contribution toward understanding its pathogenesis, and may lead to the development of novel prophylactic and treatment strategies. Evidenced-based treatment strategy is recommended for the management in BD patients. This review sheds light on the immunopathogenesis and pharmacogenetics of BD with special attention to the treatment targeting gene polymorphisms. In conclusion, the potential of genetically guided treatment in BD takes us back to the future for an accurate management strategy of this serious rheumatic disease. The ongoing discovery of pivotal genes related to the susceptibility, manifestations, disease activity and treatment options provide substantial hope to the reduced frequency of BD, effective control and improvement in the prognosis. Targeted gene therapy could be a leading option in the treatment armamentarium of BD.

Molecular Genetic Advances in Uveitis

Uveitis is usually considered as an intraocular inflammation characterized by variety of clinical features. Behcet's disease (BD), Vogt-Koyanagi-Harada (VKH) syndrome, acute anterior uveitis (AAU), and birdshot chorioretinopathy (BCR) are examples of noninfectious forms of uveitis. Although the precise pathogenesis remains unclear, accumulating evidence shows that complex genetic backgrounds coupled with an aberrant immune response may be implicated in the development of uveitis. The complement and pattern recognition systems are both important factors of the innate immune system and are involved in the pathogenesis of uveitis. Copy number variants (CNVs) of complement component 4 have been found to be associated with BD and VKH syndrome, but not with AAU. Several CNVs and gene polymorphisms of toll-like receptors were found to be associated with BD. Leukocytes are an important part of the adaptive immune system and various molecules on these cells play an important role in the development of uveitis. Genes encoding for human leukocyte antigens (HLAs) have been shown to be associated with certain uveitis entities, including BD (HLA-B51), VKH syndrome (HLA-DR4, DRB1/DQA1), AAU (HLA-B27), and BCR (HLA-A29). Genome wide association studies showed that the IL-23R locus was a shared risk factor for multiple uveitis entities including BD, AAU, and VKH syndrome. In addition, various other non-HLA genes are also associated with BD or VKH syndrome, such as IL-10, STAT4, STAT3, and UBAC2. These studies support the hypothesis that genetic factors play a key role in the pathogenesis of uveitis.

mRNA Expression Level of Interleukin Genes in the Determining Phases of Behçet's Disease

Background

Behçet's disease (BD), first described in 1937 as a triadic complex of symptoms (oral aphthae, genital ulcers, and hypopyon uveitis), is a chronic, relapsing, multisystemic idiopathic inflammatory disease.

Objective

The objective of this study was to investigate the usability of messenger RNA (mRNA) expression of cytokine genes for following up patients with BD and also assess polymorphisms in these genes as to how they influence mRNA expression.

Methods

This study investigated the role of the IL1A -889(C/T), IL1B -511(C/T), and IL2 -330(T/G) polymorphisms by polymerase chain reaction (PCR)-restriction fragment length polymorphisms and the expression levels of the genes by real-time PCR in BD.

Results

The frequency of the IL2 -330 G allele was found to be significantly higher in patients with BD. A decreased level of IL1A gene expression was found in the patient group with clinically active BD compared to controls. Increased IL1B gene expression levels werefound in patient groups with active, inactive, or ocular BD (p<0.001). IL2 gene expression level manifested no significant change compared to controls in the patient group with clinically active BD; it increased in the groups with clinically inactive BD or ocular involvement.

Conclusion

IL1A, IL1B, and IL2 gene expression, and IL2 promoter polymorphisms, may be valuable markers for predicting risk in the development of BD. We believe that the results reveal the importance of achieving a better understanding of BD and the prospects of developing future therapeutic strategies.

The roles of genetic factors in uveitis and their clinical significance

BACKGROUND

Uveitis is a diverse group of intraocular inflammatory disease and is a significant cause of visual loss worldwide. Recent studies have identified various endogenous immune mechanisms and genetic factors that are involved in the pathogenesis of uveitis. This review provides an overview on the role of genetics in the development and clinical course of uveitis.

METHODS

PUBMED was used for literature search, and articles published from 1970 to 2012 that evaluated the genetic associations and mechanisms involved in the development and clinical features of uveitis were included.

RESULTS

Studies have demonstrated associations between various genetic factors and the development and clinical course of intraocular inflammatory conditions. Genes involved included genes expressing interleukins, chemokines, chemokine receptors, and tumor necrosis factor and genes involved in complement system, oxidation, and other intracellular molecular pathways.

CONCLUSION

Multiple genetic factors play important roles in the pathogenesis of uveitis and may influence the clinical course of uveitis. Further studies to investigate the genetic mechanisms of uveitis might identify additional genetic associations and might have the potential for identifying novel therapeutic targets in the treatment of intraocular inflammation.

Interleukin-1-related genes polymorphisms in Turkish patients with Behçet disease: a meta-analysis

OBJECTIVES

Polymorphisms in the Interleukin (IL)-1-related genes at the locations -889, -511, + 3962 and mspa1l 1100 have been investigated for possible association with Behçet's disease (BD).

METHODS

A literature-based search was conducted to identify all relevant studies. Five independent studies from Turkish population met the included criteria.

RESULTS

IL-1α -889 CT [odds ratio (OR) = 0.72, 95% confidence interval (CI) = 0.55-0.95], IL-1α -889 TT (OR = 0.61, 95% CI = 0.40-0.93), IL-1β + 3962 C (OR = 1.41, 95% CI = 1.07-1.88), IL-1β + 3962 T (OR = 0.71, 95% CI = 0.53-0.94) IL-1β + 3962 CC (OR = 2.08, 95% CI = 1.08-3.99), IL-1β + 3962 CT (OR = 0.58, 95% CI = 0.38-0.88), IL-1 receptor antagonist (IL-1 Ra) mspa1l 1100 CT (OR = 0.69, 95% CI = 0.49-0.96), IL-1 Ra mspa1l 1100 TT (OR = 1.50, 95% CI = 1.08-2.08) had a significant association with BD. The pooled estimates for IL-1α -889 C, IL-1α -889 CC, IL-1α -889 T had a non-significant association with BD.

CONCLUSIONS

IL-1α -889 CT, IL-1α -889 TT, IL-1β + 3962 C, IL-1β + 3962 T, IL-1β + 3962 CC, IL-1β + 3962 CT, IL-1 Ra mspa1l 1100 CT, IL-1Ra mspa1l 1100 TT promoter polymorphisms may confer susceptibility to BD in Turkish population.

Interleukin-2 gene polymorphism in Turkish patients with Behçet's disease and its association with ocular involvement

Behçet's disease (BD) is a chronic immune-mediated systemic disease, characterized by oral and genital lesions and ocular inflammation. Several cytokine genes may play crucial roles in host susceptibility to BD, because the cytokine production capacity varies among individuals and depends on the cytokine gene polymorphisms. The association of the interleukin (IL)-2 gene polymorphisms with the susceptibility to BD was investigated in this study. DNA samples were obtained from a Turkish population of 97 patients with BD and 76 healthy control subjects. Polymorphisms of IL-2 gene at position -330 and +166 were determined using the polymerase chain reaction with sequence-specific primers. In the patients with BD, there was a significantly increased frequency of IL-2 -330 GT genotype. Interestingly, we demonstrated that the frequencies of IL-2 -330 GT and IL-2 + 166 GG genotypes were increased in BD patients with ocular involvement, whilst IL-2 -330 TT genotype was significantly decreased. Also, analysis of allele frequency demonstrated that the presence of G allele at position +166 of IL-2 seems to be a risk factor for ocular involvement. These results reveal that IL-2 -330 GT genotype may be a susceptibility factor for BD, whereas IL-2 -330 TT genotype seems to display a protective association with BD. Additionally, IL-2 gene polymorphisms might be associated with ocular involvement in BD.

Association of macrophage migration inhibitory factor gene polymorphisms with Behçet's disease in a Han Chinese population

OBJECTIVE

To examine whether polymorphisms of the macrophage migration inhibitory factor (MIF) gene are associated with Behçet's disease (BD) in a Han Chinese population.

DESIGN

Case-control study.

PARTICIPANTS

A total of 600 patients with BD and 600 age-, sex-, and ethnically matched healthy controls were enrolled.

METHODS

Two single nucleotide polymorphisms (SNPs), rs755622 and rs2096525, were genotyped using a polymerase chain reaction (PCR) restriction fragment length polymorphism assay. Allele and genotype frequencies were compared between patients and controls using the chi-square test. The expression of MIF was examined by real-time PCR.

MAIN OUTCOME MEASURES

Association of SNPs in MIF with BD.

RESULTS

Significantly decreased frequencies of the rs755622 genotype GG and G allele were found in patients with BD compared with controls. The frequencies of the genotype TT and T allele of the SNP rs2096525 were significantly lower in patients with BD compared with controls. Stratification analysis showed that the frequencies of rs755622 genotype GG in the oral aphthae, genital ulceration, or hypopyon subgroups were significantly decreased compared with controls (all P(c) < 0.05). A significantly lower frequency of the G allele of rs755622 was observed in the oral aphthae, genital ulceration, hypopyon, and arthritis subgroups compared with controls (P(c) < 0.05). The frequencies of the rs2096525 genotype TT and T alleles were also decreased in the oral aphthae, genital ulceration, hypopyon, and skin lesion subgroups compared with the controls (P(c) < 0.01). The results also showed that the expression of MIF mRNA in individuals carrying the CC genotype of rs755622 was 1.78- and 1.92-fold higher than in those carrying the GC or GG genotype.

CONCLUSIONS

This study identified a strong association of the 2 SNPs, rs755622 and rs2096525, in the MIF gene with BD and suggests that the involvement of MIF in BD may be through regulation of its mRNA expression.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.