Protection of leukotriene receptor antagonist against aspirin-induced bronchospasm in asthmatics

Aspirin Challenge-Induced Genome-Wide DNA Methylation Profile of Peripheral Blood Lymphocytes in Aspirin-Exacerbated Respiratory Disease

Genetic variation and epigenetic factors are thought to contribute to the development of hypersensitivity to aspirin. DNA methylation fluctuates dynamically throughout the day. To discover new CpG methylation in lymphocytes associated with aspirin-exacerbated respiratory disease (AERD), we evaluated changes in global CpG methylation profiles from before to after an oral aspirin challenge in patients with AERD and aspirin-tolerant asthma (ATA). Whole-genome CpG methylation levels of peripheral blood mononuclear cells were quantified with an Illumina 860K Infinium Methylation EPIC BeadChip array and then adjusted for inferred lymphocyte fraction (ILF) with GLINT and Tensor Composition Analysis. Among the 866,091 CpGs in the array, differentially methylated CpGs (DMCs) were found in 6 CpGs in samples from all 12 patients with asthma included in the study (AERD, n = 6; ATA, n = 6). DMCs were found in 3 CpGs in the 6 ATA samples and in 615 CpGs in the 6 AERD samples. A total of 663 DMCs in 415 genes and 214 intergenic regions differed significantly in the AERD compared with the ATA. In promoters, 126 CpG loci were predicted to bind to 38 transcription factors (TFs), many of which were factors already known to be involved in the pathogenesis of asthma and immune responses. In conclusion, we identified 615 new CpGs methylated in peripheral blood lymphocytes by oral aspirin challenge in AERD but not in ATA. These findings indicate that oral aspirin challenge induces epigenetic changes in ILFs, specifically in AERD patients, possibly via changes in TF binding, which may have epigenetic effects on the development of AERD.

The Saudi initiative for asthma - 2024 update: Guidelines for the diagnosis and management of asthma in adults and children

The Saudi Initiative for Asthma 2024 (SINA-2024) is the sixth version of asthma guidelines for the diagnosis and management of asthma for adults and children that was developed by the SINA group, a subsidiary of the Saudi Thoracic Society. The main objective of the SINA is to have guidelines that are up-to-date, simple to understand, and easy to use by healthcare workers dealing with asthma patients. To facilitate achieving the goals of asthma management, the SINA Panel approach is mainly based on the assessment of symptom control and risk for both adults and children. The approach to asthma management is aligned for age groups: adults, adolescents, children aged 5-12 years, and children aged <5 years. SINA guidelines have focused more on personalized approaches reflecting a better understanding of disease heterogeneity with the integration of recommendations related to biologic agents, evidence-based updates on treatment, and the role of immunotherapy in management. The medication appendix has also been updated with the addition of recent evidence, new indications for existing medication, and new medications. The guidelines are constructed based on the available evidence, local literature, and the current situation at national and regional levels. There is also an emphasis on patient-doctor partnership in the management that also includes a self-management plan.

Aspirin-exacerbated respiratory disease: Updates in the era of biologics

OBJECTIVE

Aspirin-exacerbated respiratory disease (AERD) is a chronic respiratory condition characterized by severe chronic rhinosinusitis with nasal polyps (CRSwNP), eosinophilic asthma, and respiratory reactions to cyclooxygenase inhibitors. The management of AERD has evolved recently with the availability of respiratory biologics for treatment of severe asthma and CRSwNP. The objective of this review is to provide an update on the management of AERD in the era of respiratory biologic therapy.

DATA SOURCES

A literature review of pathogenesis and treatment of AERD, with a specific focus on biologic therapies in AERD, was performed through publications gathered from PubMed.

STUDY SELECTIONS

Original research, randomized controlled trials, retrospective studies, meta-analyses, and case series of high relevance are selected and reviewed.

RESULTS

Aspirin therapy after desensitization (ATAD) and respiratory biologic therapies targeting interleukin (IL)-4Rα, IL-5, IL-5Rα, and immunoglobulin E, all have some efficacy in the treatment of CRSwNP and asthma in patients with AERD. There are currently no head-to-head studies comparing ATAD vs respiratory biologic therapy, or specific respiratory biologics, for asthma and CRSwNP in patients with AERD.

CONCLUSION

Advances in our understanding of the fundamental drivers of the chronic respiratory inflammation in asthma and CRSwNP have led to the identification of several potential therapeutic targets for these diseases that can be used in patients with AERD. Further study of the use of ATAD and biologic therapy, independently and together, will help to inform future treatment algorithms for patients with AERD.

Genome-wide DNA methylation profile of peripheral blood lymphocytes from subjects with nonsteroidal anti-inflammatory drug-induced respiratory diseases

BACKGROUND

Significant changes in CpG methylation have been identified in nasal polyps, which are the main targets of nonsteroidal anti-inflammatory drug-exacerbated respiratory disease (NERD); however, these polyps are composed of various cellular components. In the present study, whole-genome CpG methylation in peripheral blood lymphocytes (PBLs) was analyzed to define the epigenetic changes in lymphocytes, which are the primary immune cells involved in NERD.

MATERIALS AND METHODS

Genomic DNA from peripheral blood mononuclear cells from 27 NERD and 24 aspirin-tolerant asthma (ATA) was subjected to bisulfate conversion and a methylation array. Quantitative CpG methylation, the β-values as a quantitative measure of DNA methylation, in lymphocytes were calculated after adjustments for cellular composition.

RESULTS

Fifty-six hypermethylated and three hypomethylated differentially methylated CpGs (DMCs) in PBLs in the NERD compared with ATA. The top 10 CpG loci predicted the methylation risk score, with a positive predictive value of 91.3%, a negative predictive value of 81.5% and an accuracy of 84.3%. As demonstrated in the nasal polyps, 30 DMCs were predicted to bind to the following 10 transcription factors, ranked in descending order: AP-2alphaA, TFII-1, STAT4, FOXP3, GR, c-Est-1, E2F-1, XBP1, ENKTF-1 and NF-1. Gene ontology analysis identified 13 categories such as regulation of T-helper 17 cell differentiation, including SMAD7 and NFKBIZ. PBLs in NERD contained no DMCs in genes associated with the prostaglandin and leukotriene pathways, which were found in ATA.

CONCLUSION

PBLs in NERD form a unique pattern of DNA CpG methylation, and the combined analysis may provide predictive values for NERD.

Efficacy of treatment with montelukast, fluticasone propionate and budesonide liquid suspension for the prevention of recurrent asthma paroxysms in children with wheezing disorders

One-third of the children who suffer from first-time wheezing are estimated to experience recurrences; however, no standard therapeutic strategy with which to prevent these recurrences currently exists. A few studies have compared the three drugs commonly used for the treatment of persistent asthma in children to identify the most effective one for preventing recurrent wheezing. In this study, in an aim to determine the most effective of these drugs, we recruited patients <5 years of age with recurrent wheezing at our hospital, and assigned them randomly to either the oral montelukast [leukotriene receptor antagonist (LTRA)], the inhaled fluticasone propionate (FP), or the inhaled budesonide suspension (BUD) groups for 12-week treatments. We then determined the treatment efficacy (symptomatic improvement) by recording the number of wheezing episodes and emergency visits, the daily treatment cost, the mean accumulated down time and the patient compliance; we then compared the results among the groups. All treatments were found to be equally effective. The daily cost of inhaled FP was lower than that of oral LTRA and inhaled BUD (P<0.00001). The difference in the mean accumulated down time between these groups was not significant (P=0.132). The adherence (patient compliance) to LTRA was significantly higher than the adherence to inhaled corticosteroids (ICS) (P<0.017). On the whole, the findings of this study indicated that all three treatments prevented recurrent wheezing in our pediatric population. FP was found to be more convenient, to require fewer doses, and that it could be easily adjusted. Patient adherence/compliance to treatment was significantly better with LTRA than with ICS.

The Saudi Initiative for Asthma - 2019 Update: Guidelines for the diagnosis and management of asthma in adults and children

This is the fourth version of the updated guidelines for the diagnosis and management of asthma, developed by the Saudi Initiative for Asthma (SINA) group, a subsidiary of the Saudi Thoracic Society. The main objective of the SINA is to have guidelines that are up to date, simple to understand, and easy to use by healthcare workers dealing with asthma patients. To facilitate achieving the goals of asthma management, the SINA panel approach is mainly based on the assessment of symptom control and risk for both adults and children. The approach to asthma management is now more aligned for different age groups. The guidelines have focused more on personalized approaches reflecting better understanding of disease heterogeneity with integration of recommendations related to biologic agents, evidence-based updates on treatment, and role of immunotherapy in management. The medication appendix has also been updated with the addition of recent evidence, new indications for existing medication, and new medications. The guidelines are constructed based on the available evidence, local literature, and current situation at national and regional levels. There is also an emphasis on patient–doctor partnership in the management that also includes a self-management plan.

Diabetes Downregulates Allergen-Induced Airway Inflammation in Mice

Previous studies described that allergic diseases, including asthma, occur less often than expected in patients with type 1 diabetes. Here, we investigated the influence of diabetes on allergic airway inflammation in a model of experimental asthma in mice. Diabetes was induced by intravenous injection of alloxan into 12 h-fasted A/J mice, followed by subcutaneous sensitization with ovalbumin (OVA) and aluminum hydroxide (Al(OH)₃), on days 5 and 19 after diabetes induction. Animals were intranasally challenged with OVA (25 μg), from day 24 to day 26. Alloxan-induced diabetes significantly attenuated airway inflammation as attested by the lower number of total leukocytes in the bronchoalveolar lavage fluid, mainly neutrophils and eosinophils. Suppression of eosinophil infiltration in the peribronchiolar space and generation of eosinophilotactic mediators, such as CCL-11/eotaxin, CCL-3/MIP-1α, and IL-5, were noted in the lungs of diabetic sensitized mice. In parallel, reduction of airway hyperreactivity (AHR) to methacholine, mucus production, and serum IgE levels was also noted under diabetic conditions. Our findings show that alloxan diabetes caused attenuation of lung allergic inflammatory response in A/J mice, by a mechanism possibly associated with downregulation of IgE antibody production.

Factors correlated with repeated aspirin dosing during aspirin desensitization

BACKGROUND

Aspirin desensitization is an appropriate procedure for many patients with aspirin-exacerbated respiratory disease (AERD). Patients can require aspirin re-dosing, which prolongs the desensitization process. The frequency of this is not widely reported, nor is it known which patients will require multiple re-dosing.

OBJECTIVE

To determine the frequency of and factors associated with repeat aspirin re-dosing during desensitization.

METHODS

Charts of aspirin desensitization procedures from 2011 to 2016 at the University of Michigan Allergy/Immunology Clinic were reviewed. Reactions with provoking doses and number of dose repetitions were characterized. Previous AERD history, medical history, medications, and baseline spirometry were also recorded. Bivariate correlation and multivariate logistic regression were used to analyze associations between patient characteristics and need for repeated dosing of aspirin.

RESULTS

A total of 84 positive-reacting patients during desensitization were identified. Of these patients, 33% required 2 or more aspirin dose repetitions during desensitization. Requiring 2 or more repeat doses during desensitization was associated with male gender (odds ratio = 6.194, P = .008), forced expiratory volume in 1 second (FEV₁) decrease during desensitization (odds ratio = 1.075 per percent point drop, P = .021), and initial aspirin provoking dose during desensitization of 81 mg or lower (odds ratio = 11.111, P = .003). No association was found with pre-desensitization medications, asthma severity, AERD duration, or number/character of reported previous aspirin reactions.

CONCLUSION

During aspirin desensitization for AERD, approximately one third of our patients require multiple repeat doses. Risk factors for multiple repeated doses include male gender, drop in FEV₁, and lower aspirin provoking doses during desensitization. This information can help inform which patients may require multiple re-dosing for desensitization.

Current Knowledge and Management of Hypersensitivity to Aspirin and NSAIDs

Aspirin and nonsteroidal anti-inflammatory drugs (NSAIDs) are some of the most common culprits of drug-induced hypersensitivity reactions, and can lead to a wide array of adverse effects. The accurate and timely diagnosis of aspirin and NSAID-induced hypersensitivity reactions is important for both patient safety and for the initiation of appropriate disease-specific management and treatment. Because there are no reliably validated in vitro tests available, aspirin and NSAID challenges are considered to be the criterion standard for the diagnosis of these hypersensitivity reactions, though in some patients the diagnosis can be made on the basis of a clear clinical history.

Frequency and severity of reactions to a 325-mg aspirin dose during desensitization

BACKGROUND

The frequency with which patients with aspirin-exacerbated respiratory disease (AERD) react to 325 mg of aspirin during aspirin desensitization, or fail to react at all, is not fully known.

OBJECTIVE

To determine the rate and type of reaction at 325 mg of aspirin during desensitization.

METHODS

A retrospective study of 104 patients who underwent aspirin desensitization from 2010 to 2016 was performed. A standard desensitization protocol (starting at 20-40 mg, progressing through 325 mg, and extinguishing reactions by dose repetition) was used. Reactions were defined by upper respiratory tract symptoms, lower respiratory tract symptoms, and/or forced expiratory volume in 1 second decrease of 15% or greater. Patients who did and did not react were compared by logistic regression.

RESULTS

Eighty-four patients reacted (81%) and 20 did not (19%). Seventy-seven patients who had a provoking reaction at 162 mg of aspirin or less subsequently extinguished their reactions before they reached a dose of 325 mg and had no problems at that dose; one subsequent 325-mg reaction occurred during a protocol violation. One initial provoking reaction to 325 mg occurred. Both 325-mg reactions were mild, and neither met the forced expiratory volume in 1 second criterion for a clinically meaningful change. The remaining 5 patients could not complete the protocol because of persistent reactions or social reasons. Reactors were more likely to have had asthma for more than 10 years than nonreactors (odds ratio, 3.2; 95% confidence interval, 1.0-10.3; P = .05).

CONCLUSION

During aspirin desensitization for AERD, provoking reactions at the 325-mg dose are rare (1%) and mild. Patients who react at 162 mg or less and extinguish their reactions may be able to administer the 325-mg dose at home.

Asthma phenotypes in children and stratified pharmacological treatment regimens

INTRODUCTION

Asthma is the most common inflammatory disease in childhood. The interaction of genetic, environmental and host factors may contribute to the development of childhood asthma and defines its progress, including persistence and severity. Until now, various classifications of childhood asthma phenotypes have been suggested based on patient's age during onset of symptoms, type of inflammatory cells, response to treatment and disease severity. Many efforts have been carried out to identify childhood asthma phenotypes and to clarify which are the risk factors that define asthma prediction and the response to therapy. The identification of asthma phenotypes has not only prognostic but also therapeutic role. However, the classification of asthma phenotypes is complex due to the heterogeneity of the disease. Areas covered: The current childhood asthma phenotypes and the new therapeutic strategies for each phenotype are reviewed. Expert commentary: There are multiple phenotypes in childhood asthma and it is crucial to define them before the initiation of personalized treatment. Both the therapeutic strategy and monitoring should follow the recent guidelines.

The Saudi Initiative for Asthma - 2016 update: Guidelines for the diagnosis and management of asthma in adults and children

This is an updated guideline for the diagnosis and management of asthma, developed by the Saudi Initiative for Asthma (SINA) group, a subsidiary of the Saudi Thoracic Society. The main objective of SINA is to have guidelines that are up to date, simple to understand and easy to use by nonasthma specialists, including primary care and general practice physicians. SINA approach is mainly based on symptom control and assessment of risk as it is the ultimate goal of treatment. The new SINA guidelines include updates of acute and chronic asthma management, with more emphasis on the use of asthma control in the management of asthma in adults and children, inclusion of a new medication appendix, and keeping consistency on the management at different age groups. The section on asthma in children is rewritten and expanded where the approach is stratified based on the age. The guidelines are constructed based on the available evidence, local literature, and the current situation in Saudi Arabia. There is also an emphasis on patient-doctor partnership in the management that also includes a self-management plan.

Clinical course of patients with aspirin-exacerbated respiratory disease: can we predict the prognosis?

AIM

This study aimed to identify prognostic factors of aspirin-exacerbated respiratory disease by comparing clinical and genetic data with the clinical course.

PATIENTS & METHODS

Patients were classified into two groups according to their response to inhalation rechallenge with lysine-aspirin after at least 1 year of regular treatment with antiasthmatic medications.

RESULTS

Forty eight patients (39.3%, group I) had negative responses, whereas 74 patients (60.7%, group II) had positive responses (n = 23) or were not rechallenged owing to persistent symptoms (n = 51). FEV₁ at diagnosis and follow-up were significantly lower in group II than in group I. The CCR3 polymorphism at -520T/G differed significantly between the two groups, whereas no difference was found in other SNPs.

CONCLUSION

Baseline FEV₁ and lower lung function after treatment were clinical factors indicating a poor prognosis of aspirin-exacerbated respiratory disease. The G allele of CCR3 -520T>G was associated with persistent bronchial hypersensitivity to aspirin.

Guidelines for severe uncontrolled asthma

Since the publication, 9 years ago, of the latest SEPAR (Spanish Society of Pulmonology and Thoracic Surgery) Guidelines on Difficult-to-Control Asthma (DCA), much progress has been made in the understanding of asthmatic disease. These new data need to be reviewed, analyzed and incorporated into the guidelines according to their level of evidence and recommendation. Recently, consensus documents and clinical practice guidelines (CPG) addressing this issue have been published. In these guidelines, specific mention will be made of what the previous DCA guidelines defined as "true difficult-to-control asthma". This is asthma that remains uncontrolled after diagnosis and a systematic evaluation to rule out factors unrelated to the disease itself that lead to poor control ("false difficult-to-control asthma"), and despite an appropriate treatment strategy (Spanish Guidelines for the Management of Asthma [GEMA] steps 5 and 6): severe uncontrolled asthma. In this respect, the guidelines propose a revised definition, an attempt to classify the various manifestations of this type of asthma, a proposal for a stepwise diagnostic procedure, and phenotype-targeted treatment. A specific section has also been included on DCA in childhood, aimed at assisting healthcare professionals to improve the care of these patients.

Impact of montelukast on asthma associated with rhinitis, and other triggers and co-morbidities

INTRODUCTION

Rhinitis and other specific triggers or co-morbidities (tobacco exposure, excess weight, aspirin sensitivity or heredity factors) are frequently associated with uncontrolled asthma. Asthma associated with these exacerbating factors appears to be related to an increase in leukotriene-mediated inflammation.

METHODS

We reviewed the role of montelukast, a leukotriene receptor antagonist, in the treatment of asthma associated with these factors by using the PubMed database to search the English and French biomedical literature for articles describing randomized-controlled trials, large observational studies and reviews (published up to May 2012, inclusive).

RESULTS

Montelukast, either alone or in combination with other drugs, is an effective treatment against rhinitis-associated asthma. Montelukast also offers therapeutic benefits against exercise-induced asthma or in cases of asthma linked to tobacco exposure, excess weight or aspirin hypersensitivity. Thus, for some patients, montelukast may constitute an alternative to the gold-standard treatment of inhaled corticosteroids. Polymorphisms in several genes encoding proteins of the leukotriene signaling pathway may contribute to the variability in response to montelukast.

CONCLUSIONS

In conclusion, we have shown that montelukast treatment could be of particular benefit to subgroups of patients with asthma associated with rhinitis, exercise, tobacco exposure, being overweight or aspirin hypersensitivity.

Unraveling the genetic basis of aspirin hypersensitivity in asthma beyond arachidonate pathways

Although aspirin-exacerbated respiratory disease (AERD) has attracted a great deal of attention because of its association with severe asthma, it remains widely under-diagnosed in the asthmatic population. Oral aspirin challenge is the best method of diagnosing AERD, but this is a time-consuming procedure with serious complications in some cases. Thus, development of non-invasive methods for easy diagnosis is necessary to prevent unexpected complications of aspirin use in susceptible patients. For the past decade, many studies have attempted to elucidate the genetic variants responsible for risk of AERD. Several approaches have been applied in these genetic studies. To date, a limited number of biologically plausible candidate genes in the arachidonate and immune and inflammatory pathways have been studied. Recently, a genome-wide association study was performed. In this review, the results of these studies are summarized, and their limitations discussed. In addition to the genetic variants, changes in methylation patterns on CpG sites have recently been identified in a target tissue of aspirin hypersensitivity. Finally, perspectives on application of new genomic technologies are introduced; these will aid our understanding of the genetic pathogenesis of aspirin hypersensitivity in asthma.

Identification of GPR99 protein as a potential third cysteinyl leukotriene receptor with a preference for leukotriene E4 ligand

The cysteinyl leukotrienes (cys-LTs), leukotriene C4 (LTC4), a conjugation product of glutathione and eicosatetraenoic acid, and its metabolites, LTD4 and LTE4, are lipid mediators of smooth muscle constriction and inflammation in asthma. LTD4 is the most potent ligand for the type 1 cys-LT receptor (CysLT1R), and LTC4 and LTD4 have similar lesser potency for CysLT2R, whereas LTE4 has little potency for either receptor. Cysltr1/Cysltr2(-/-) mice, lacking the two defined receptors, exhibited a comparable dose-dependent vascular leak to intradermal injection of LTC4 or LTD4 and an augmented response to LTE4 as compared with WT mice. As LTE4 retains a cysteine residue and might provide recognition via a dicarboxylic acid structure, we screened cDNAs within the P2Y nucleotide receptor family containing CysLTRs and dicarboxylic acid receptors with trans-activator reporter gene assays. GPR99, previously described as an oxoglutarate receptor (Oxgr1), showed both a functional and a binding response to LTE4 in these transfectants. We generated Gpr99(-/-) and Gpr99/Cysltr1/Cysltr2(-/-) mice for comparison with WT and Cysltr1/Cysltr2(-/-) mice. Strikingly, GPR99 deficiency in the Cysltr1/Cysltr2(-/-) mice virtually eliminated the vascular leak in response to the cys-LT ligands, indicating GPR99 as a potential CysLT3R active in the Cysltr1/Cysltr2(-/-) mice. Importantly, the Gpr99(-/-) mice showed a dose-dependent loss of LTE4-mediated vascular permeability, but not to LTC4 or LTD4, revealing a preference of GPR99 for LTE4 even when CysLT1R is present. As LTE4 is the predominant cys-LT species in inflamed tissues, GPR99 may provide a new therapeutic target.

Association of single nucleotide polymorphisms on Interleukin 17 receptor A (IL17RA) gene with aspirin hypersensitivity in asthmatics

AIM

To investigate the association of single nucleotide polymorphisms (SNP) on IL17RA gene with Aspirin Exacerbated Respiratory Disease (AERD) and the functional effect of these variants on expression of IL17RA gene products.

MATERIAL & METHODS

15 SNPs of IL17RA gene were analyzed in 825 normal controls and 143 subjects with AERD and 411 with aspirin-tolerant asthma (ATA) and functionally characterized using measurement of protein and m-RNA expression.

RESULT

Minor alleles frequencies of the three SNPs (-1075 A>G, -947 A>G, -50 C>T) and one haplotype (BL1_ht1) were significantly lower in AERD compared to those in ATA (p(corr)=0.002-0.03). IL17RA protein expression and mRNA amount in CD14(+) peripheral blood monocytes and mononuclear cells were significantly increased in subjects carrying the common alleles homozygote compared with those carrying the minor alleles.

CONCLUSIONS

The minor alleles of the three SNPs may decrease the risk of AERD via attenuation of IL17RA gene expression.

Role of leukotriene receptor antagonists in the management of pediatric asthma: an update

At present, the main indications for leukotriene receptor antagonists (LTRA) in pediatric asthma are as add-on therapy to inhaled corticosteroids (ICS) and as initial controller therapy in children with mild asthma, especially those who cannot or will not use ICS. LTRA are also useful for patients who have concomitant rhinitis, and patients with viral-induced wheeze and exercise-induced asthma. It should be noted that the benefits of LTRA therapy have been demonstrated in children as young as 6 months of age and recent clinical trials have further proven the benefits of LTRA in acute asthma exacerbations. However, considering the important pro-inflammatory effects that leukotrienes (LT) have in experimental models of asthma, it may seem surprising that LTRA treatment outcomes are not better and that in some clinical trials only a minority of patients could be classified as full responders. This could be explained by potential additional LT receptors that are not affected by LTRA. Such receptors could represent new therapeutic targets in asthma. Furthermore, progress in differentiating between asthma phenotypes that result from different pathogenic mechanisms, some of which may involve LT to a lesser degree, should lead to an improved, personalized use of LTRA for treating asthma.

Association analysis of formyl peptide receptor 2 (FPR2) polymorphisms and aspirin exacerbated respiratory diseases

Aspirin-exacerbated respiratory diseases (AERD) are associated with the metabolism of arachidonic acid. FPR2 (formyl peptide receptor2) is a high-affinity ligand receptor for potent anti-inflammatory lipid metabolites: lipoxins. Thus, functional alterations of the FPR2 may contribute to AERD. We investigated the relationship between single-nucleotide polymorphisms (SNPs) in the FPR2 and AERD. Asthmatics were categorized into AERD <15% decreases in forced expiratory volume in one second (FEV(1)), and/or naso-ocular reactions after oral aspirin challenge (n=170) and aspirin-tolerant asthma (ATA, n=268). In all, 11 SNPs were genotyped. FPR2 protein expressions on CD14-positive monocytes in peripheral blood were measured using flow cytometric analysis. We performed RT-PCR of the FPR2 mRNA expressed by peripheral blood mononuclear cells. Logistic regression analysis showed that the minor allele frequency of FPR2 -4209T>G (rs1769490) in intron 2 was significantly lower in the AERD group (n=170) than in the ATA group (n=268) (P=0.006, P(corr)=0.04, recessive model). The decline of FEV(1) after aspirin challenge was significantly lower in the subjects with GG homozygotes of FPR2 -4209T>G than those with the other genotypes (P=0.0002). Asthmatic homozygotes for FPR2 -4209T>G minor allele exhibited significantly higher FPR2 protein expression in CD14-positive monocytes than did those with the common allele of FPR2 -4209T>G allele (P=0.01). There was no difference in the expression of the wild form and the exon 2 deleted variant form of FPR2 gene according to the genotypes of FPR2 -4209T>G. The minor allele at FPR2 -4209T>G may have a protective role against the development of AERD, via increase of FPR2 protein expression in inflammatory cells.

Association of the variants in AGT gene with modified drug response in Korean aspirin-intolerant asthma patients

The angiotensinogen (AGT) gene enhances the effect of several bronchoconstrictors and produces a peptide that is accumulated in the airways of asthma patients; events that may underpin the pathogenesis of aspirin-intolerant asthma (AIA). To carry out a case-control analysis between AGT and aspirin-induced bronchospasm following treatment with an anti-asthma drug, montelukast (MLK), 38 single nucleotide polymorphisms (SNPs) in AGT were genotyped in 56 AIA cohort. Genotyping was performed with TaqMan assay and haplotypes were inferred using PHASE algorithm ver. 2.0. Statistical analyses of each SNPs and haplotypes were performed using SAS version 9.1. Among 13 variants displaying significant signals, two SNPs (+2401C>G and +2476C>T) in the intronic region of AGT were significantly associated with modification of drug response even after correction for multiple testing (P=0.0009-0.002; P(corr)=0.02-0.03). Furthermore, the two variants also exhibited associations with MLK response rate (P=0.0003-0.0006; P(corr)=0.006-0.01). Although our results are preliminary and further replication in a larger-scale group of subjects should be warranted, these observations provide evidence that AGT variants might be one of genetic factors involved in the response of anti-asthma drugs in AIA patients.

Association analysis of UBE3C polymorphisms in Korean aspirin-intolerant asthmatic patients

BACKGROUND

Aspirin-intolerant asthma (AIA), as an asthma phenotype that involves the upper or lower airways, occurs from excessive leukotriene production on administration of nonsteroidal anti-inflammatory drugs. The UBE3C gene on chromosome 7 is a member of the E3 ligase enzymes and is implicated in the ubiquitin-proteasome pathway. This pathway is involved in immune responses to inflammation, including asthma.

OBJECTIVE

To investigate whether the UBE3C polymorphisms are associated with the risk of AIA.

METHODS

Twenty-four nonmonomorphic genetic variants of UBE3C were genotyped in 163 patients with AIA and 429 controls with aspirin-tolerant asthma. After genotyping, logistic analyses were performed and haplotypes of each individual were inferred using the PHASE algorithm.

RESULTS

Logistic analyses revealed that 2 polymorphisms (rs3802122 and rs6979947) in the intron showed significant associations with risk of AIA (P < .001 and P(corr) = .002 in both single nucleotide polymorphisms; odds ratios, 0.61 and 0.60, respectively). In associations with haplotypes, haplotype 2, which contains all the significantly associated single nucleotide polymorphisms and was infrequent in AIA compared with aspirin-tolerant asthma, was associated with aspirin hypersensitivity in asthmatic patients (P = .003 and P(corr) = .03; odds ratio, 0.64; 95% confidence interval, 0.47-0.86).

CONCLUSIONS

The rs3802122 and rs6979947 polymorphisms were significantly associated with the risk of AIA. However, further studies are required to establish the underlying mechanism by which UBE3C and its polymorphisms affect the risk of AIA.

What's new in asthma pathophysiology and immunopathology?

Research on asthma pathophysiology over the past decade has expanded the complex repertoire involved in the pathophysiology of asthma to include inflammatory, immune and structural cells, as well as a wide range of mediators. Studies have identified a role for connective and other mesenchymal tissues involved in airway remodeling. Recent findings have implicated the innate immune response in asthma and have revealed interesting patterns of interaction between the innate and adaptive immune response and the associated complex chronic inflammatory reaction. New immune cell populations have also been added to this repertoire, including Tregs, natural killer T cells and Th17 cells. The role of the eosinophil, a prominent pathological feature in most asthma phenotypes, has also been expanding to include roles such as tissue modifiers and immune regulators via a number of fascinating and hitherto unexplored mechanistic pathways. In addition, new and significant roles have been proposed for airway smooth muscle cells, fibroblasts, epithelial and endothelial cells. Tissue remodeling is now considered an integral element of asthma pathophysiology. Finally, an intricate network of mediators, released from both immune and inflammatory cells, including thymus stromal lymphopoietin and matrix metalloproteinases, have added to the complex milieu of asthma immunity and inflammation. These findings have implications for therapy and the search for novel strategies towards better disease management. Sadly, and perhaps due to the complex nature of asthma, advances in therapeutic discoveries and developments have been limited. Thus, understanding the precise roles played by the numerous dramatis personae in this odyssey, both individually and collectively within the context of asthma pathophysiology, continues to pose new challenges. It is clear that the next stage in this saga is to embark on studies that transcend reductionist approaches to involve system analysis of the complex and multiple variables involved in asthma, including the need to narrow down the phenotypes of this condition based on careful analysis of the organs (lung and airways), cells, mediators and other factors involved in bronchial asthma.

Genome-wide and follow-up studies identify CEP68 gene variants associated with risk of aspirin-intolerant asthma

Aspirin-intolerant asthma (AIA) is a rare condition that is characterized by the development of bronchoconstriction in asthmatic patients after ingestion of non-steroidal anti-inflammatory drugs including aspirin. However, the underlying mechanisms of AIA occurrence are still not fully understood. To identify the genetic variations associated with aspirin intolerance in asthmatics, the first stage of genome-wide association study with 109,365 single nucleotide polymorphisms (SNPs) was undertaken in a Korean AIA (n = 80) cohort and aspirin-tolerant asthma (ATA, n = 100) subjects as controls. For the second stage of follow-up study, 150 common SNPs from 11 candidate genes were genotyped in 163 AIA patients including intermediate AIA (AIA-I) subjects and 429 ATA controls. Among 11 candidate genes, multivariate logistic analyses showed that SNPs of CEP68 gene showed the most significant association with aspirin intolerance (P values of co-dominant for CEP68, 6.0×10⁻⁵ to 4.0×10⁻⁵). All seven SNPs of the CEP68 gene showed linkage disequilibrium (LD), and the haplotype of CEP68_ht4 (T-G-A-A-A-C-G) showed a highly significant association with aspirin intolerance (OR  = 2.63; 95% CI  = 1.64–4.21; P = 6.0×10⁻⁵). Moreover, the nonsynonymous CEP68 rs7572857G>A variant that replaces glycine with serine showed a higher decline of forced expiratory volume in 1s (FEV₁) by aspirin provocation than other variants (P = 3.0×10⁻⁵). Our findings imply that CEP68 could be a susceptible gene for aspirin intolerance in asthmatics, suggesting that the nonsynonymous Gly74Ser could affect the polarity of the protein structure.

KIF3A, a cilia structural gene on chromosome 5q31, and its polymorphisms show an association with aspirin hypersensitivity in asthma

INTRODUCTION

The kinesin family number 3A (KIF3A) gene on the human chromosomal 5q31-33 region, which is known as a susceptibility locus for immune diseases including asthma, plays a crucial role in generation of cilia.

RESULTS

A treatment with aspirin in the human bronchial epithelial cells increased the mRNA expression level of KIF3A compared to that of the untreated control (P ≤ 0.01), and nasal polyp epithelia from aspirin-intolerant asthma (AIA) patients also showed a higher expression of KIF3A protein than aspirin-tolerant asthma controls. Further logistic analyses revealed that most polymorphisms of KIF3A were significantly associated with AIA (P = 0.0004-0.02; P(corr) = 0.004-0.04) and the decline of forced expiratory volume at 1 s (FEV(1))% by aspirin provocation (P = 0.004-0.04; P(corr) = 0.03).

DISCUSSION

Our findings suggest that the KIF3A gene and/or its polymorphisms might have a susceptibility effect on AIA, providing a new step toward controlling aspirin intolerance in asthmatics.