Association of the interleukin-1 receptor antagonist gene with asthma

Role of cytokines in multiple myeloma: IL-1RN and IL-4 VNTR polymorphisms

INTRODUCTION

The IL-1 receptor antagonist (IL-1Ra or IL-1RN) is a member of the IL-1 superfamily that functions as a competitive antagonist of the cell surface IL-1 receptor, thereby regulating various immune and inflammatory responses related to IL-1. IL-1 induces tumor growth and metastasis, while IL-1RN inhibits the secretion of IL-1α and IL-6 in cancer cells. Interleukin-4 (IL-4) is a potent anti-inflammatory cytokine, can be secreted by many types of immune cells. In this study, it was aimed to reveal the effects of IL-1RN and IL-4 VNTR polymorphisms on disease development and survival in patients with multiple myeloma (MM).

MATERIAL AND METHODS

In this study, 244 patients diagnosed with MM in hematology clinic between January 2010 and January 2021, and 179 healthy individuals were included. The genotypes of the IL-1RN VNTR polymorphism were statistically compared before treatment between patients having undergone stem cell transplantation and healthy controls, as were the genotypes of IL-4 VNTR polymorphism. Additionally, the statistically significant effects of these genotypes on survival were examined.

RESULTS

In the statistical analysis of the distribution of IL-1RN VNTR gene variants, 1/3 and 1/4 genotypes were found to be significantly higher in patients with MM compared to the healthy controls (p = 0.035). There was no significant difference between the MM patient group and the healthy controls in terms of IL-4 VNTR genotype distribution. PFS of patients with IL-1RN VNTR non-2-allele carrier genotypes was significantly shorter, but no significant effect was found on OS (p = 0.03, p = 0.786, respectively). Patients with IL-1RN VNTR non-2-allele carrier genotypes had 1.718-fold increased risk of shorter PFS.

CONCLUSIONS

In conclusion, with this study, the effects of IL-1RN VNTR and IL-4 VNTR polymorphisms on MM were evaluated for the first time in the literature. This study will shed light on ones on cytokine-MM relationship and epigenetic mechanisms.

The influence of IL1RN VNTR polymorphism on HPV infection among some tribal communities

Persistent infection of human Papillomavirus is the main etiological factor for cervical cancer. Austro-Asiatic tribes are early settlers in India and they have unique genetic variations compared to other people. The immunological response is crucial for the prevention of viral associated diseases. Interleukin-1 receptor antagonist (IL-1RN) is considered being an important regulator of host immune surveillance. A total of 45 Santali tribal women and 10 Kora tribal women were enrolled in the present study and demographic variables were recorded during collection. Genomic DNA was extracted from cervical/vaginal swab samples. IL1RN variable number of tandem repeats (VNTR) polymorphisms and HPV types were determined by PCR-based assay. Association between IL1RN VNTR polymorphisms with the HPV infections among the tribal communities was determined by logistic regression analysis. HPV18 prevalence was significantly higher among tribal women. We observed that the polymorphism A2*A2 (p = 0.022; odds ratio [OR] (95% confidence interval [CI]) = 0.16 (0.03-0.86)] were more resistant to oncogenic HPV infection. Use of oral contraceptives was associated with higher relative risk (p = 0.008; OR [95% CI] = 5.39 [1.47-19.8]) for oncogenic HPV18 positivity among the tribal women. The A2 allele homozygosity of IL1RN VNTR was identified to be associated with the protection from oncogenic HPV infection among various tribal communities of West Bengal and therefore may be a useful marker of host immune response among them.

Gene-Environment Interaction between the IL1RN Variants and Childhood Environmental Tobacco Smoke Exposure in Asthma Risk

(1) Background: Variants of the interleukin-1 receptor antagonist (IL1RN) gene, encoding an anti-inflammatory cytokine, are associated with asthma. Asthma is a chronic inflammatory disease of the airway influenced by interactions between genetic variants and environmental factors. We discovered a gene-environment interaction (GEI) of IL1RN polymorphisms with childhood environmental tobacco smoke (ETS) exposure on asthma susceptibility in an urban adult population. (2) Methods: DNA samples from the NYU/Bellevue Asthma Registry were genotyped for tag SNPs in IL1RN in asthma cases and unrelated healthy controls. Logistic regressions were used to study the GEI between IL1RN variants and childhood ETS exposures on asthma and early onset asthma, respectively, adjusting for population admixture and other covariates. (3) Results: Whereas the rare genotypes of IL1RN SNPs (e.g., GG in SNP rs2234678) were associated with decreased risk for asthma among those without ETS exposure (odds ratio OR = 0.215, p = 0.021), they are associated with increased risk for early onset asthma among those with childhood ETS (OR = 4.467, p = 0.021). (4) Conclusions: We identified a GEI between polymorphisms of IL1RN and childhood ETS exposure in asthma. Analysis of GEI indicated that childhood ETS exposure disrupted the protective effect of some haplotypes/genotypes of IL1RN for asthma and turned them into high-risk polymorphisms for early onset asthma.

IL-1RN VNTR, IL-2(-330), and IL-4 VNTR gene polymorphisms in patients with chronic rhinosinusitis with sinonasal polyposis

Background/aim

Sinonasal polyposis is a complex chronic disease displaying contributions from multiple genetic and environmental factors. In this study, we analyzed possible genetic factors that increase susceptibility to this widespread inflammatory disease.

Materials and methods

A total of 176 adult patients, including 78 patients with sinonasal polyposis and 98 healthy controls, were analyzed for IL-1RN VNTR, IL-2(-330), and IL-4 VNTR gene polymorphisms using polymerase chain reaction and enzyme restriction.

Results

IL-1RN and IL-4 VNTR polymorphisms were notably associated with sinonasal polyposis (P = 0.0001 and P = 0.036, respectively); however, regarding the IL-2(-330) gene polymorphism, no significant difference was shown between the patient and control groups (P = 0.235).

Conclusions

Our study indicates that the RN2 allele of IL-1RN and the RP1 allele of IL-4 might be risk factors for developing sinonasal polyposis.

Long Noncoding RNA Linc00632 Inhibits Interleukin-13-Induced Inflammatory Cytokine and Mucus Production in Nasal Epithelial Cells

Allergic rhinitis (AR) is an allergic disease characterized as (immunoglobulin E)-mediated type I hypersensitivity disorder. The interleukin-13 (IL-13) signaling pathway has been implicated in the pathogenesis of AR. In the present study, we investigated the regulatory role and mechanism of long noncoding RNA Linc00632 in IL-13-induced inflammatory cytokine and mucus production in nasal epithelial cells (NECs) from AR patients. We evaluated the expression of Linc00632 in nasal tissues from AR patients and in IL-13-treated NECs. We explored the role of Linc00632 in granulocyte-macrophage colony-stimulating factor (GM-CSF), eotaxin, and MUAC5AC production in IL-13-treated NECs. We searched for the potential target of Linc00632. Downregulation of Linc00632 was identified in nasal tissues of AR patients and in IL-13-treated NECs. Linc00632 inhibited IL-13-induced GM-CSF, eotaxin, and MUAC5AC production. Linc00632 targeted miR-498 and negatively regulated its expression. MiR-498 targeted IL1RN and inhibition of miR-498 suppressed IL-13-induced GM-CSF, eotaxin, and MUC5AC expression. The regulation of IL-13-induced dysfunction of NECs by Linc00632 depended on miR-498. Linc00632 inhibited IL-13-induced GM-CSF, eotaxin, and MUAC5AC production in IL-13-treated NECs by targeting miR-498.

IL-1β: a key modulator in asthmatic airway smooth muscle hyper-reactivity

Asthma is a chronic inflammatory disorder of the airway. It is characterized by airway hyper-reactivity, which can be attributed to the chronically inflamed airway. However, the molecular mechanism is still under investigation. In this article, we have shown that IL-1β is a key molecule that can orchestrate both Toll-like receptor and muscarinic receptor pathways, and that antagonizing the function of IL-1β has a promising future as a potential drug target for asthma treatment. IL-1β can activate NF-κB pathways via Toll-like receptors, and NF-κB will eventually transactivate the genes of cytokines, chemokines, proteins of the complement system, adhesion molecules and immune receptors involved in inflammation. IL-1β can activate eosinophils, which can release major basic protein (MBP) to antagonize the M2 receptors leading to excessive acetylcholine release. Acetylcholine has an effect on M3 receptors, which are related to airway smooth muscle contraction and mucus production. IL-1β is reported to activate COX-2 resulting in heterologous desensitization of adenylate cyclase and impairs relaxation of the ASM. IL-1β is involved in mediation of neutrophilic inflammation. Identification of the prominent role of IL-1β in asthma could lead to successful use of anti-IL1β agents.

IL-1 receptor antagonist reduces endotoxin-induced airway inflammation in healthy volunteers

BACKGROUND

Asthma with neutrophil predominance is challenging to treat with corticosteroids. Novel treatment options for asthma include those that target innate immune activity. Recent literature has indicated a significant role for IL-1β in both acute and chronic neutrophilic asthma.

OBJECTIVE

This study used inhaled endotoxin (LPS) challenge as a model of innate immune activation to (1) assess the safety of the IL-1 receptor antagonist anakinra in conjunction with inhaled LPS and (2) to test the hypothesis that IL-1 blockade will suppress the acute neutrophil response to challenge with inhaled LPS.

METHODS

In a phase I clinical study 17 healthy volunteers completed a double-blind, placebo-controlled crossover study in which they received 2 daily subcutaneous doses of 1 mg/kg anakinra (maximum dose, 100 mg) or saline (placebo). One hour after the second treatment dose, subjects underwent an inhaled LPS challenge. Induced sputum was assessed for neutrophils 4 hours after inhaled LPS. The effect of anakinra compared with placebo on airway neutrophil counts and airway proinflammatory cytokine levels after LPS challenge was compared by using a linear mixed-model approach.

RESULTS

Anakinra pretreatment significantly diminished airway neutrophilia compared with placebo. LPS-induced IL-1β, IL-6, and IL-8 levels were significantly reduced during the anakinra treatment period compared with those seen after placebo. Subjects tolerated the anakinra treatment well without an increased frequency of infections attributable to anakinra treatment.

CONCLUSIONS

Anakinra effectively reduced airway neutrophilic inflammation and resulted in no serious adverse events in a model of inhaled LPS challenge. Anakinra is a potential therapeutic candidate for treatment of asthma with neutrophil predominance in diseased populations.

Intermediary quantitative traits--an alternative in the identification of disease genes in asthma?

Intermediary quantitative traits are a possible alternative for the identification of disease genes. This may be particularly relevant when diagnostic criteria are not very well defined as described for asthma. We analyzed serum samples from 944 individuals of 218 asthma families for 17 cytokines (eotaxin, GM-CSF, IFNγ, IL1B, IL1RA, IL-4, IL-5, IL-6, IL-8, IL-10, IL-12(p40), IL-13, IL-17, IL-23, IL-33, TSLP and TNF-α) and determined the heritability. Linked chromosomal regions were identified by a genome-wide analysis using 334 autosomal microsatellite marker and association tested by further 550 SNP marker at genes implicated earlier with immune response. Heritability varied with TNF-α and IL-8 levels having the highest and TSLP having the lowest heritability. Linkage was significantly increased only for IL-12(p40) at D17S949. There were multiple significant single-nucleotide polymorphisms (SNP) associations (P<0.05) as found in the transmission disequilibrium test, whereas only a few replicated in parents or children only. These include SNPs in IL1RN that were associated with IL-33 and TSLP levels, and a SNP in NR3C2 that was associated with eotaxin, IL-13 and IFN-γ levels. Circulating level of serum cytokines exhibits genetic associations with asthma traits that are otherwise not detected using clinical diagnosis or when the clinical details are ambiguous.

High risk association of IL-1 receptor antagonist (IL-1RN) VNTR polymorphism with asthma in a North Indian population: a pilot study

BACKGROUND

A pilot case-control study was conducted to evaluate the role of IL-1 receptor antagonist (IL-1RN) VNTR penta-allelic polymorphism in asthma that has been associated with various inflammatory diseases worldwide. This is the first case-control study conducted in India, investigating the role of IL-1RN VNTR polymorphism in asthma pathogenesis.

METHODS

A case-control study was performed with a total of 824 adult subjects, inducting 410 asthma patients and 414 healthy controls from North India. The genotypes were identified by polymerase chain reaction.

RESULTS

Statistical analysis for the IL-1RN VNTR polymorphism revealed that the IL-1RN(*)2 allele was significantly associated with asthma with OR=1.45, 95% CI (1.15-1.85) and p=0.001. The IL-1RN(*)2/2 genotype posed a risk towards asthma with OR=1.66, 95% CI (0.97-2.86) and p=0.048. Most of the phenotypic traits were significantly associated with the disease.

CONCLUSIONS

IL-1RN(*)2 allele is a high risk factor for asthma in the studied North Indian population.

Interleukins, from 1 to 37, and interferon-γ: receptors, functions, and roles in diseases

Advancing our understanding of mechanisms of immune regulation in allergy, asthma, autoimmune diseases, tumor development, organ transplantation, and chronic infections could lead to effective and targeted therapies. Subsets of immune and inflammatory cells interact via ILs and IFNs; reciprocal regulation and counter balance among T(h) and regulatory T cells, as well as subsets of B cells, offer opportunities for immune interventions. Here, we review current knowledge about ILs 1 to 37 and IFN-γ. Our understanding of the effects of ILs has greatly increased since the discoveries of monocyte IL (called IL-1) and lymphocyte IL (called IL-2); more than 40 cytokines are now designated as ILs. Studies of transgenic or knockout mice with altered expression of these cytokines or their receptors and analyses of mutations and polymorphisms in human genes that encode these products have provided important information about IL and IFN functions. We discuss their signaling pathways, cellular sources, targets, roles in immune regulation and cellular networks, roles in allergy and asthma, and roles in defense against infections.

Importance of cytokines in murine allergic airway disease and human asthma

Asthma is a common, disabling inflammatory respiratory disease that has increased in frequency and severity in developed nations. We review studies of murine allergic airway disease (MAAD) and human asthma that evaluate the importance of Th2 cytokines, Th2 response-promoting cytokines, IL-17, and proinflammatory and anti-inflammatory cytokines in MAAD and human asthma. We discuss murine studies that directly stimulate airways with specific cytokines or delete, inactivate, neutralize, or block specific cytokines or their receptors, as well as controversial issues including the roles of IL-5, IL-17, and IL-13Ralpha2 in MAAD and IL-4Ralpha expression by specific cell types. Studies of human asthmatic cytokine gene and protein expression, linkage of cytokine polymorphisms to asthma, cytokine responses to allergen stimulation, and clinical responses to cytokine antagonists are discussed as well. Results of these analyses establish the importance of specific cytokines in MAAD and human asthma and have therapeutic implications.

IL-1 Gene Cluster is Not Linked to Aggressive Periodontitis

The interleukin-1 (IL-1) gene family has been associated with susceptibility to periodontal diseases, including aggressive periodontitis (AgP); however, the results are still conflicting. The present study investigated the association between IL-1 genes and AgP using 70 markers spanning the 1.1-Mb region, where the IL-1 gene family maps, and exploring both the linkage disequilibrium (LD) and the haplotype structure in a case-control study including 95 patients and 121 control individuals. No association between AgP and IL1A, IL1B, and IL1RN genes was found in either single-point or haplotype analyses. Also, the LD map of the region 2q13–14 under the Malécot model for multiple markers showed no causal association between AgP and polymorphisms within the region (p = 0.207). In conclusion, our findings failed to support the existence of a causative variant for generalized AgP within the 2q13–14 region in an Italian Caucasian population.

IL1B polymorphisms modulate cystic fibrosis lung disease

RATIONALE

Variability in pulmonary disease severity is found in patients with cystic fibrosis (CF) who have identical mutations in the CF transmembrane conductance regulator (CFTR) gene. We hypothesized that one factor accounting for heterogeneity in pulmonary disease severity is variation in the family of genes affecting the biology of interleukin-1 (IL-1), which impacts acquisition and maintenance of Pseudomonas aeruginosa infection in animal models of chronic infection.

METHODS

We genotyped 58 single nucleotide polymorphisms (SNPs) in the IL-1 gene cluster in 808 CF subjects from the University of North Carolina and Case Western Reserve University (UNC/CWRU) joint cohort. All were homozygous for DeltaF508, and categories of "severe" (cases) or "mild" (control subjects) lung disease were defined by the lowest or highest quartile of forced expired volume (FEV(1)) for age in the CF population. After adjustment for age and gender, genotypic data were tested for association with lung disease severity. Odds ratios (ORs) comparing severe versus mild CF were also calculated for each genotype (with the homozygote major allele as the reference group) for all 58 SNPs. From these analyses, nine SNPs with a moderate effect size, OR < or =0.5 or >1.5, were selected for further testing. To replicate the case-control study results, we genotyped the same nine SNPs in a second population of CF parent-offspring trios (recruited from Children's Hospital Boston), in which the offspring had similar pulmonary phenotypes. For the trio analysis, both family-based and population-based associations were performed.

RESULTS

SNPs rs1143634 and rs1143639 in the IL1B gene demonstrated a consistent association with lung disease severity categories (P < 0.10) and longitudinal analysis of lung disease severity (P < 0.10) in CF in both the case-control and family-based studies. In females, there was a consistent association (false discovery rate adjusted joint P-value <0.06 for both SNPs) in both the analysis of lung disease severity in the UNC/CWRU cohort and the family-based analysis of affection status.

CONCLUSION

Our findings suggest that IL1beta is a clinically relevant modulator of CF lung disease.

An interdisciplinary analysis of sex and gender in relation to the pathogenesis of bronchial asthma

BACKGROUND

An increasing number of studies confirm that pathogenesis and prevalence of bronchial asthma are age and sex dependent. Detailed physiological mechanisms of the changing sex ratios with age are not fully known, however, the gender (socio-cultural) factors are also imperative. Although multiple factors definitely influence the pathogenesis of asthma, only individual or few combinations of these have been investigated.

METHODS

The terms 'sex', 'gender' and plausible combinations of both were systematically researched in selected databases (Medline, Scopus) or other sources, including publications from January 2000 to June 2007. Generated articles were categorized, either as endogenous or exogenous factors influencing the pathogenesis of asthma, and divided into the following subgroups: genetic, immunological, hormonal, gynaecological, nutritional, and environmental parameters.

RESULTS

An increasing number of studies investigate the influence of sex and gender in the aetiology, therapy and prevention of asthma. While their results are still debatable, others regarding its initiation, perpetuation and cessation have been clarified. Recent insights into interactions at biomolecular and immunological levels greatly contribute to clarifying sex-specific influences. Despite occasional oversimplifications, a trend for explanations considering the complex interplay of different factors can be observed. This work is in line with this trend and offers explanation models from our point of view.

CONCLUSIONS

Some disagreements regarding the patho-physiology, diagnosis, treatment and prevention of asthma still prevail. Nevertheless, in order to better appreciate its complexity, openness to and persistent consideration for interdisciplinary as well as sex- and gender-related factors is required of the medical-research community in future investigations.

Gene polymorphisms of IL-6(-174) G/C and IL-1Ra VNTR in asthmatic children

OBJECTIVE

To check for the association of genetic polymorphisms of IL-6-(-174)G/C and IL-1RaVNTR with the susceptibility and severity of asthma in Egyptian children.

METHODS

Subjects included 69 asthmatic children and 98 healthy unrelated controls from the Nile Delta of Egypt. Cases consisted of 20 males and 49 females with an age mean +/- SD is 7.5 +/- 2.1 ranging between 2-13 years. DNA amplification using PCR with sequence-specific primers was done for detection of promotor single nucleotide polymorphism of IL-6 gene as well as intron 2 VNTR of IL-1Ra gene. Frequency of case-genotypes or alleles were compared to controls using Fisher exact test and Odds ratio.

RESULTS

Cases showed significant higher frequency of the genotypes: IL-6-174 GG (P<0.05, OR=3.2, 95% CI=1.09-10) that was evident mainly in the uncontrolled asthma subgroup indicative of the possibility of being a severity genotype. All cases as well as case-subgroups showed high significant frequency of IL-1Ra A1A1 (p<0.0001, OR=1.5, 95% CI=1.3-1.8). This may be considered a susceptibility genotype. Cases have also shown significant lower frequency of IL-6(-174) GC and IL-1Ra A1A2 genotypes (P<0.001 and P<0.0001 respectively).

CONCLUSION

IL-6 and IL-1Ra polymorphisms can be considered genetic markers for bronchial asthma susceptibility and/or severity among Egyptian children. This may have a potential impact on family counseling and management.

Meta-analysis of genome-wide linkage studies of asthma and related traits

BACKGROUND

Asthma and allergy are complex multifactorial disorders, with both genetic and environmental components determining disease expression. The use of molecular genetics holds great promise for the identification of novel drug targets for the treatment of asthma and allergy. Genome-wide linkage studies have identified a number of potential disease susceptibility loci but replication remains inconsistent. The aim of the current study was to complete a meta-analysis of data from genome-wide linkage studies of asthma and related phenotypes and provide inferences about the consistency of results and to identify novel regions for future gene discovery.

METHODS

The rank based genome-scan meta-analysis (GSMA) method was used to combine linkage data for asthma and related traits; bronchial hyper-responsiveness (BHR), allergen positive skin prick test (SPT) and total serum Immunoglobulin E (IgE) from nine Caucasian asthma populations.

RESULTS

Significant evidence for susceptibility loci was identified for quantitative traits including; BHR (989 pedigrees, n = 4,294) 2p12-q22.1, 6p22.3-p21.1 and 11q24.1-qter, allergen SPT (1,093 pedigrees, n = 4,746) 3p22.1-q22.1, 17p12-q24.3 and total IgE (729 pedigrees, n = 3,224) 5q11.2-q14.3 and 6pter-p22.3. Analysis of the asthma phenotype (1,267 pedigrees, n = 5,832) did not identify any region showing genome-wide significance.

CONCLUSION

This study represents the first linkage meta-analysis to determine the relative contribution of chromosomal regions to the risk of developing asthma and atopy. Several significant results were obtained for quantitative traits but not for asthma confirming the increased phenotype and genetic heterogeneity in asthma. These analyses support the contribution of regions that contain previously identified asthma susceptibility genes and provide the first evidence for susceptibility loci on 5q11.2-q14.3 and 11q24.1-qter.

Asthma from a pharmacogenomic point of view

Pharmacogenomics, a fascinating, emerging area of biomedical research is strongly influenced by growing availability of genomic databases, high-throughput genomic technologies, bioinformatic tools and artificial computational modelling approaches. One main area of pharmacogenomics is the discovery of new drugs and drug targets with molecular genetic, genomic or even bioinformatic methods; the other is the study of how genomic differences influence the variability in patients' responses to drugs. From a genetic point of view, asthma is multifactorial, which means that the susceptibility to the disease is determined by interactions between multiple genes, and involves important non-genetic factors such as the environment for their expression. In this review, we summarize collective evidence from linkage and association studies that have consistently reported suggestive linkage or association of asthma or its associated phenotypes to polymorphic markers and single nucleotide polymorphisms in selected chromosomes. Genes that have been found implicated in the disease are potential new drug targets and several pharmacological investigations are underway to utilize these new discoveries. Next, we will focus on the inter-individual variability in anti-asthmatic drug responses and review the recent results in this topic.

A functional and regulatory map of asthma

The prevalence and morbidity of asthma, a chronic inflammatory airway disease, is increasing. Animal models provide a meaningful but limited view of the mechanisms of asthma in humans. A systems-level view of asthma that integrates multiple levels of molecular and functional information is needed. For this, we compiled a gene expression compendium from five publicly available mouse microarray datasets and a gene knowledge base of 4,305 gene annotation sets. Using this collection we generated a high-level map of the functional themes that characterize animal models of asthma, dominated by innate and adaptive immune response. We used Module Networks analysis to identify co-regulated gene modules. The resulting modules reflect four distinct responses to treatment, including early response, general induction, repression, and IL-13-dependent response. One module with a persistent induction in response to treatment is mainly composed of genes with suggested roles in asthma, suggesting a similar role for other module members. Analysis of IL-13-dependent response using protein interaction networks highlights a role for TGF-beta1 as a key regulator of asthma. Our analysis demonstrates the discovery potential of systems-level approaches and provides a framework for applying such approaches to asthma.

[Asthma genetic factors]

Asthma is a chronic inflammatory airways disease, with a rising prevalence, particularly in childhood, and is considered an important public health problem. Its familial transmission is recognised, while the description and identification of the genes implicated in this disease are a challenge. In this revision paper the authors give a comprehensive explanation of the associated genes as well as the laboratorial methods that allow their identification.

Interleukin-1R antagonist gene and pre-natal smoke exposure are associated with childhood asthma

The interleukin-1 receptor antagonist (IL1RN) is a potent anti-inflammatory cytokine. In the present study, association of the human IL1RN gene polymorphisms with asthma, bronchial hyperresponsiveness and forced expiratory volume in one second/forced vital capacity ratio was tested and the data was stratified by environmental tobacco smoke exposure in order to investigate a gene-smoking interaction. In an unselected subset (n = 921) of the Isle of Wight birth (UK) cohort, which has previously been evaluated for asthma and related manifestations at ages 1, 2, 4 and 10 yrs, three IL1RN single nucleotide polymorphisms (SNP) were genotyped. Logistic regression and repeated measurement models for tests of association using a representative SNP rs2234678 were used, as all SNPs tested were in strong linkage disequilibrium. In the overall analysis, the SNP rs2234678 was not associated with asthma. However, in the stratum with maternal smoking during pregnancy the rs2234678 GG genotype significantly increased the relative risk of asthma in children, both in analyses of repeated asthma occurrences and persistent asthma. In conclusion, the present results show that in the first decade of life, the gene-environment interaction of the interleukin-1 receptor antagonist gene polymorphism rs2234678 and maternal smoking during pregnancy increased the risk for childhood asthma.

The vitamin D slant on allergy

Oral vitamin D supplementation has been introduced into modern medicine to prevent rickets without the knowledge that this may have profound immunological consequences. The main vitamin D metabolite calcitriol suppresses dendritic cell maturation and consecutive Th(1) cell development, which has independently described as a key mechanism of allergy development. Animal studies and epidemiological surveys now provide a first link of early vitamin D supplementation and later allergy where several vitamin D regulated genes seem to be involved. A randomized clinical trial of vitamin D supplementation could be a further step to follow up the vitamin hypothesis.

Candidate gene association studies and evidence for gene-by-gene interactions

Candidate gene studies in asthma are a powerful and valuable tool in asthma genetics. Although the quality of small-scale, freely associating studies has been questionable, increasingly serious efforts are made to establish, replicate, and verify association results. Association studies may help us to better understand the mechanisms underlying asthma. They may create hypotheses and help to direct functional studies to targets that are likely to give valuable results. However, they should not be over-interpreted; only biologic proof can verify associations between genetic variations and a certain disease outcome. The insight that gene-by-gene and gene-by-environment interactions may be crucial for understanding and pinpoint the complex mechanisms of genetic regulation of multifactorial diseases has gained momentum in the last years when technical improvement allowed for the effective genotyping and analysis of great numbers of polymorphisms in large populations. It can be expected that from this area of research new and exciting results will follow soon.

Association between interleukin-1 receptor antagonist gene and asthma-related traits in a German adult population

BACKGROUND

A recent study in German and Italian families associated variants in the interleukin-1 receptor antagonist (IL1RA) gene with asthma. The aim of the present study was to further investigate the role of single nucleotide polymorphisms (SNPs) in the IL1RA gene in the development of atopy and lifelong asthma in a population-based study.

METHODS

DNA samples from the German centres of the European Community Respiratory Health Survey were analysed for genetic variants in the IL1RA gene and the development of asthma, atopy and bronchial hyperreactivity.

RESULTS

Carriers of the rare G allele of SNP rs447713 had a significantly increased risk of developing asthma (P = 0.0013) and allergic sensitization (P = 0.0119). Carriers of the rare C allele of SNP rs3087271 had an increased risk of asthma (P = 0.0227) and high immunoglobulin E (IgE) levels (P = 0.0232). A haplotype built from eight SNPs in the IL1RA gene (A-C-A-G-A-C-G-A) was associated with a higher prevalence of asthma (P = 0.007) and high total IgE (P = 0.02). Bronchial hyperreactivity was positively associated with the haplotype A-C-G-G-A-C-G-C (P = 0.02) and negatively with the A-C-G-G-A-C-T-C (P = 0.03).

CONCLUSION

A previously described association between IL1RA and asthma in families could be reproduced in a population-based sample. The genetic variants of IL1RA gene do not to seem to affect asthma alone, but to act as modulators of asthma-related traits as well, where different haplotypes drive the development of different phenotypes.

Childhood asthma: breakthroughs and challenges

As we move forward, our goal is to control and eliminate asthma and other allergic disorders. This may come through broadly applied manipulation of environmental, dietary, and infectious risk factors, possibly during the perinatal period. Or we may learn to identify genetically susceptible children and to intervene with individualized genotype-specific treatment before the onset of disease. Maybe we'll learn how to block the mechanisms that give rise to chronic inflammation, or how to subdue Th2 activation. However, as the Swedish proverb says--Don't throw away the old bucket until you know whether the new one holds water. To continue using the old bucket, we have to fix the leaks. One approach to reducing asthma disparities is through traditional disease prevention stages. Primary prevention targets asthma incidence; secondary prevention mitigates established disease and involves disease detection, management, and control; and tertiary prevention is the reduction of complications caused by severe disease. Once causative factors at each level of disease prevention are understood, this knowledge can be translated into clinical practice and public health policy. We need reliable diagnostic criteria to provide correct treatment for infants and toddlers. This will require longitudinal cohort studies supported by assessment of pulmonary function and inflammatory markers. We must find ways to convince more physicians to embrace controller therapy for more severe disease, and to identify the patients with less severe disease who also require ongoing controller therapy. We need to close the gap between what we know and what we do in practice. We need to link basic research to healthcare delivery, and to gain acceptance and support from the intended recipients of new interventions. We need better strategies for improving adherence. We need accountability, foresight, and imagination.

Interleukin 1 receptor antagonist gene polymorphism and risk of lung cancer: a possible interaction with polymorphisms in the interleukin 1 beta gene

Tobacco smoking is the main risk factor for lung cancer. Only 10-15% of smokers develop lung cancer, suggesting that genetic factors are of importance in determining individual susceptibility to the disease. Several studies in recent years indicate that chronic inflammation is a cofactor in lung carcinogenesis. We have previously reported an association of interleukin 1 beta gene (IL1B) polymorphisms with lung cancer risk. Interleukin-1 receptor antagonist (IL-1Ra) has been implicated in carcinogenesis of different cancer types. IL-1Ra binds competitively to the same membrane receptor as interleukin-1beta (IL-1beta) and thereby acts as an antagonist to the pro-inflammatory actions of IL-1beta. The aim of the study was to examine whether a common VNTR polymorphism in the interleukin 1 receptor antagonist gene (IL1RN) is associated with lung cancer risk. Due to the tight relationship between IL1RN and IL1B, we also explored the possibility of an interaction between the two genes. The study population comprised of 340 non-small cell lung cancer cases and 412 healthy controls of Norwegian origin. Our results indicate that individuals homozygous for the IL1RN*1 allele and carrying the IL1B-31T allele had increased risk of non-small cell lung cancer (odds ratio C/T 3.08; 1.10-8.62 and T/T 5.87; 2.15-16.05). Furthermore, IL1RN*1 carriers had nearly two-fold higher levels of bulky/hydrophobic DNA adducts in the lung. Our findings support the significance of IL1 gene cluster polymorphisms and risk of lung cancer.

The role of genetics in the development of asthma and atopy

PURPOSE OF REVIEW

The mapping of complex traits such as asthma and atopy is one of the most important and central areas of human genetics. This article will present an overview of the current status of genetic studies of asthma and atopy using genome screens and association studies that have occurred in the literature since January 2003.

RECENT FINDINGS

Many regions of the genome have been found to have linkage with the phenotypes of asthma and atopy. Over 70 variants in candidate genes have been reported to be associated with these phenotypes. The main regions these variants have been found are on chromosomes 2q, 5q, 6p, 11q, 12q, 16q and 17q. Five potential asthma susceptibility genes or complexes have been identified using a positional approach. These are ADAM33, DPP10, PHF11 and SETDB2, GPRA and SPINK5. It is evident that environmental factors will influence the expression of genes and the ultimate clinical phenotype of asthma and atopy.

SUMMARY

The development of asthma and atopy involves many genes and environmental factors. An understanding of their genetic basis has great implications for their management.

Genotyping single nucleotide polymorphisms by MALDI mass spectrometry in clinical applications

Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry has become one of the most powerful and widely applied technologies for SNP scoring and determination of allele frequencies in the post-genome sequencing era. Although different strategies for allele discrimination combined with MALDI were devised, in practice only primer extension methods are nowadays routinely used. This combination enables the rapid, quantitative, and direct detection of several genetic markers simultaneously in a broad variety of biological samples. In the field of molecular diagnostics, MALDI has been applied to the discovery of genetic markers, that are associated with a phenotype like a disease susceptibility or drug response, as well as an alternative means for diagnostic testing of a range of diseases for which the responsible mutations are already known. It is one of the first techniques with which whole genome scans based on single nucleotide polymorphisms were carried out. It is equally well suited for pathogen identification and the detection of emerging mutant strains as well as for the characterization of the genetic identity and quantitative trait loci mapping in farm animals. MALDI can also be used as a detection platform for a range of novel applications that are more demanding than standard SNP genotyping such as mutation/polymorphism discovery, molecular haplotyping, analysis of DNA methylation, and expression profiling. This review gives an introduction to the application of mass spectrometry for DNA analysis, and provides an overview of most studies using SNPs as genetic markers and MALDI mass spectrometric detection that are related to clinical applications and molecular diagnostics. Further, it aims to show specialized applications that might lead to diagnostic applications in the future. It does not speculate on whether this methodology will ever reach the diagnostic market.

Linkage disequilibrium analysis of case-control data: an application to generalized aggressive periodontitis

Several studies have shown a role for the involvement of interleukin (IL)-1 gene cluster polymorphisms in the risk of periodontal diseases. In the present study, we tested polymorphisms, derived from genes of the IL-1 cluster, for association with generalized aggressive periodontitis (GAP) through both allelic association and by constructing a linkage disequilibrium (LD) map of the 2q13-14 disease candidate region. The IL-1RN (VNTR) genotype distribution observed was significantly different in GAP and control subjects (P=0.019). We also observed some evidence for an association between GAP and the IL-1B(+3953) polymorphism (P=0.039). The pattern of association in the region, represented as an LD map, identifies a recombination hot area between the IL-1B(+3953) and IL-1B(-511) polymorphisms. Multilocus modelling of association with disease gives a location for the peak association at the IL-1B(+3953) marker, although support for the peak is not significant. Haplotype analysis identifies a IL-1B(+3953)-IL-1B(-511) haplotype as having the lowest P-value in the region. Recognition of the presence of a recombination hot area between the IL-1B(+3953) and IL-1B(-511) polymorphisms will have an important bearing on future efforts to develop higher resolution SNP analysis in this region for both this and other diseases for which this cluster is implicated.

Interleukin-1beta causes pulmonary inflammation, emphysema, and airway remodeling in the adult murine lung

The production of the inflammatory cytokine interleukin (IL)-1 is increased in lungs of patients with chronic obstructive pulmonary disease (COPD) or asthma. To characterize the in vivo actions of IL-1 in the lung, transgenic mice were generated in which human IL-1beta was expressed in the lung epithelium with a doxycycline-inducible system controlled by the rat Clara cell secretory protein (CCSP) promoter. Induction of IL-1beta expression in the lungs of adult mice caused pulmonary inflammation characterized by neutrophil and macrophage infiltrates. IL-1beta caused distal airspace enlargement, consistent with emphysema. IL-1beta caused disruption of elastin fibers in alveolar septa and fibrosis in airway walls and in the pleura. IL-1beta increased the thickness of conducting airways, enhanced mucin production, and caused lymphocytic aggregates in the airways. Decreased immunostaining for the winged helix transcription factor FOXA2 was associated with goblet cell hyperplasia in IL-1beta-expressing mice. The production of the neutrophil attractant CXC chemokines KC (CXCL1) and MIP-2 (CXCL2), and of matrix metalloproteases MMP-9 and MMP-12, was increased by IL-1beta. Chronic production of IL-1beta in respiratory epithelial cells of adult mice causes lung inflammation, enlargement of distal airspaces, mucus metaplasia, and airway fibrosis in the adult mouse.