Association of FcεR1-β polymorphisms with asthma and associated traits in Australian asthmatic families

BACKGROUND: Asthma is a genetically complex disease, and is characterized by elevated serum immunoglobulin E (IgE) levels, elevated blood eosinophil counts and increased airway responsiveness. Polymorphisms in the beta subunit of the high affinity receptor for IgE (FcepsilonR1-beta) have been previously associated with these phenotypes and with an increased risk of asthma. OBJECTIVE: To investigate the association of all known bi-allelic polymorphisms in FcepsilonR1-beta to asthma and quantitative traits associated with asthma in a selected sample of Australian asthmatic children and their nuclear families. METHODS: Australian Caucasian nuclear families (n = 134 subjects) were recruited on the basis of a child proband with current, severe, symptomatic asthma. The quantitative traits assessed included serum levels of total IgE and specific IgE to house dust mite and mixed grass, blood eosinophil counts and the dose-response slope of the forced expiratory volume in 1 s to histamine provocation. RESULTS: Neither the Leu181 nor the E237G mutations were detected in this population. Allele B of RsaI intron 2 (RsaI_in2*B) was significantly associated with physician-diagnosed asthma (ever) (P = 0.002). Alleles of both the RsaI_in2 and RsaI exon 7 (RsaI_ex7) polymorphisms were significantly associated with loge total serum IgE levels and the combined RAST index. RsaI_ex7 was also associated with loge blood eosinophil counts. These associations were independent of age, sex and familial correlations. CONCLUSION: This study supports a role for the FcepsilonR1-beta gene or a nearby gene in the pathogenesis of asthma.     

Cysteinyl leukotriene receptor 1 promoter polymorphism is associated with aspirin-intolerant asthma in males

BACKGROUND: Cysteinyl leukotrienes (CysLTs) play important roles in the pathogenesis of eosinophilic airway inflammation characterized by bronchoconstriction, mucus secretion and airway hyper-responsiveness via cysteinyl leukotriene receptor 1 (CysLTR1)-mediated mechanism. CysLTR1-selective antagonists have anti-bronchoconstrictive and anti-inflammatory effects in asthma, particularly aspirin-intolerant asthma (AIA). METHODS: To investigate the association of CysLTR1 with AIA development, we identified three single nucleotide polymorphisms (SNPs), -634C>T, -475A>C, -336A>G, in the 5' upstream region of CysLTR1 gene using a direct sequencing method in 105 AIA patients, 110 ASA-tolerant asthma (ATA) patients and 125 normal healthy controls (NC). RESULTS: Significant differences were observed in allele frequencies of the three SNPs within male subjects; Male AIA patients had higher frequencies of the minor alleles of these three SNPs than male control groups (P=0.03 for AIA vs. NC; P=0.02 for AIA vs. ATA). Moreover, three-SNP haplotype, ht2 [T-C-G], was associated with increased disease risk (odds ratio (OR)=2.71, P=0.03 for AIA vs. NC; OR=2.89, P=0.02 for AIA vs. ATA) in males. CysLTR1 haplotypes were also associated with altered gene expression; luciferase activity was significantly enhanced with the ht2 [T-C-G] construct in comparison with the ht1 [C-A-A] construct in human Jurkat cells (P=0.04). CONCLUSION: These results suggest that genetic variants of CysLTR1 are associated with AIA in a Korean population, and may modulate CysLTR1 expression.     

IgE高亲和力受体β链基因多态性与湖北汉族人变应性哮喘易感性的研究

目的探讨IgE高亲和力受体β链( high-affinity IgE receptor β gene, Fc ε RI β)基因启动子-109位C/T和编码区Glu237Gly基因多态性与湖北汉族人变应性哮喘易感性及血浆总IgE的关系. 方法采用聚合酶链反应-限制性片段长度多态性技术检测 Fc ε RI β基因启动子区-109位和编码区Glu237Gly两位点多态性,采用病例-对照法研究了216例变应性哮喘患者和198名对照. 结果 (1)湖北汉族人变应性哮喘患者 Fc ε RI β基因启动子区-109位T/T、T/C和C/C基因型频率是0.403、0.491和0.106;与对照相比差异无显著性(χ2=0.384,P＞0.05),但变应性哮喘组T/T基因型患者血浆总IgE对数值(2.539±0.8325)与T/C基因型的对数值(2.278±1.089)和C/C基因型的对数值(2.323±0.7852)相比差异具有显著性.(2)变应性哮喘患者 Fc ε RI β基因Glu237Gly位点Glu/Glu、Glu/Gly和Gly/Gly基因型频率为0.579、0.370和0.051,与正常对照相比差异具有显著性(χ2=13.62,P＜0.01),变应性哮喘患者Gly/Gly基因型血浆总IgE对数值为(2.622±0.9374),与Glu/Glu和Glu/Gly相比差异具有显著性. 结论 Fc ε RI β基因启动子区-109位T/T基因型与血浆总IgE高度相关,编码区237位Gly/Gly基因型与中国湖北汉族人变应性哮喘及血浆高IgE相关.     

<Emphasis Type="Italic">ADAM33 </Emphasis>polymorphisms are associated with aspirin-intolerant asthma in the Japanese population

Multiple single nucleotide polymorphisms (SNPs) within ADAM33 have been reported to be associated with asthma and bronchial hyper-responsiveness in Caucasian populations. We examined whether these SNPs contribute to a predisposition to asthma, especially aspirin-intolerant asthma (AIA), in the Japanese population. Ten polymorphic sites (ST+4, ST+7, T1, T2, T+1, V-3, V-2, V-1, V4, V5) were genotyped in 102 AIA patients, 282 aspirin-tolerant asthma (ATA) patients and 120 control (CTR) subjects by direct sequencing. Haplotype frequencies were estimated by the expectation-maximization method. Differences in allele and haplotype frequencies among phenotypes were analyzed by the chi-square and permutation tests. ST+7, V-1 and V5 sites in the AIA group were significantly different from those in the ATA group (P=0.034–0.004) and from those in the CTR group (P=0.019–0.002). Haplotypes at three sites (ST+7, V-1, and V5) were significantly different in frequency between the AIA and ATA (P=0.008) or CTR (P=0.001) groups. Sequence variations in ADAM33 are likely to correlate with susceptibility to AIA in the Japanese population. The authors declare that they have no conflict of interest.     

Association of thromboxane A2 receptor gene polymorphism with the phenotype of acetyl salicylic acid-intolerant asthma

BACKGROUND AND OBJECTIVE: The thromboxane A2 receptor (TBXA2R) is a receptor for a potent bronchoconstrictor, TBXA2 which is known to be related to bronchial asthma and myocardial infarction. TBXA2R antagonist and TBX synthase inhibitors have been found to be effective in the management of asthmatic patients. This study was aimed to evaluate whether genetic variants of TBXA2R may be related with development of acetyl salicylic acid (ASA)-intolerant asthma (AIA). METHODS: TBXA2R gene polymorphisms (TBXA2R+795T>C, TBXA2R+924T>C) were determined using a single-base extension method in 93 AIA patients compared with 172 patients with ASA-tolerant asthma (ATA) and 118 normal controls (NCs) recruited from the Korean population. HLA DPB1*0301 genotype was performed using a direct sequencing method. RESULTS: The rare C allele frequency of TBXA2R+795T>C was significantly higher in AIA than in ATA (P=0.03) and the TBXA2R+795T>C polymorphism was also associated with extent of percent fall in forced expiratory volume in 1 s (FEV1) after the inhalation of lysine-acetyl salicylic acid in AIA patients (P=0.009); AIA patients homozygous for the +795 C allele had a greater percent fall of FEV1 compared with individuals with TBXA2R+795 CT or TT genotypes. The frequency of patients carrying both the TBXA2R+795T>C rare allele and HLA DPB1(*)0301 was significantly higher in AIA patients (29.4%) than in ATA patients (7.3%) (P=0.008, odds ratio=5.3). CONCLUSION: These results suggest that the polymorphism of TBXA2R+795T>C may increase bronchoconstrictive response to ASA, which could contribute to the development of the AIA phenotype.     

Single nucleotide polymorphisms predisposing to asthma in children of Mauritian Indian and Chinese Han ethnicity

Our objective was to investigate the distributions of six single nucleotide polymorphisms (SNPs) MS4A2 E237G, MS4A2 C-109T, ADRB2 R16G, IL4RA I75V, IL4 C-590T, and IL13 C1923T in Mauritian Indian and Chinese Han children with asthma. This case-control association study enrolled 382 unrelated Mauritian Indian children, 193 with asthma and 189 healthy controls, and 384 unrelated Chinese Han children, 192 with asthma and 192 healthy controls. The SNP loci were genotyped using polymerase chain reaction (PCR)-restriction fragment length polymorphism for the Chinese Han samples and TaqMan real-time quantitative PCR for the Mauritian Indian samples. In the Mauritian Indian children, there was a significant difference in the distribution of IL13 C1923T between the asthma and control groups (P=0.033). The frequency of IL13 C1923T T/T in the Mauritian Indian asthma group was significantly higher than in the control group [odds ratio (OR)=2.119, 95% confidence interval=1.048-4.285]. The Chinese Han children with asthma had significantly higher frequencies of MS4A2 C-109T T/T (OR=1.961, P=0.001) and ADRB2 R16G A/A (OR=2.575, P=0.000) than the control group. The IL13 C1923T locus predisposed to asthma in Mauritian Indian children, which represents an ethnic difference from the Chinese Han population. The MS4A2 C-109T T/T and ADRB2 R16G A/A genotypes were associated with asthma in the Chinese Han children.     

IgE高亲和力受体β链基因与中国湖北成人变应性哮喘的关系

目的:探讨IgE高亲和力受体β链基因(FcεRⅠβ)启动子-109位和编码区Glu237Gly基因多态性与湖北成人变应性哮喘及血浆总IgE的关系。方法:采用聚合酶链反应-限制性片段长度多态性技术检测FcεRⅠβ基因启动子区-109位和编码区Glu237Gly两位点多态性,采用病例-对照法共研究106例成人变应性哮喘患者和106例相匹配的对照者。结果:①成人变应性哮喘患者FcεRⅠβ基因启动子区-109位T/T、T/C和C/C基因型频率是0.415、0.491和0.094;与对照相比差异无显著(χ²=0.5575,P＞0.05),但成人变应性哮喘组T/T基因型患者血浆总IgE对数值为2.6490±0.9241与T/C基因型的2.2960±1.1040和C/C基因型的2.3130±0.8052相比差异显著。②FcεRⅠβGlu237Gly位点Glu/Glu、Glu/Gly和Gly/Gly基因型频率为0.566、0.377和0.057,与正常对照相比差异显著(χ²=7.31,P＜0.05),Gly/Gly基因型血浆总IgE对数值为2.7220±0.9374,与Glu/Glu和Glu/Gly相比差异显著。结论:IgE高亲和力受体β链启动区-109位T/T基因型与血浆总IgE高度相关,编码区237位Gly/Gly基因型与湖北汉族成人变应性哮喘及血浆高IgE相关。     

Specific immunoglobulin E for staphylococcal enterotoxins in nasal polyps from patients with aspirin-intolerant asthma

BACKGROUND: Nasal polyps infiltrated with eosinophils are commonly found in chronic asthmatic patients, more frequently in those with aspirin-intolerant asthma (AIA) than aspirin-tolerant asthma (ATA). Some studies have suggested a contribution of superantigens derived from Staphylococcus sp to nasal polyposis and eosinophilia, but their relative importance in AIA and ATA subjects is unknown. OBJECTIVE: We investigated whether local production of specific IgE to staphylococcal enterotoxins A and B (SEA and SEB) and relationships with markers of eosinophilic inflammation differ in the nasal polyps of AIA and ATA subjects. METHODS: Fifteen AIA subjects with positive responses to lysine-aspirin bronchoprovocation and 15 ATA subjects underwent polypectomy. Immunoassays were used to quantify eosinophil cationic protein (ECP), IL-5, mast cell tryptase, soluble IL-2 receptors (sIL-2R), total IgE, and specific IgE for SEA and SEB. RESULTS: ECP levels in nasal polyp homogenates were higher in AIA subjects than in ATA subjects (P < 0.02), with no significant differences in tryptase, IL-5 or sIL-2R. Total IgE, and specific IgE to both SEA and SEB, were detectable in some nasal polyps from both subject groups, but median levels were markedly higher in AIA subjects than in ATA subjects (P = 0.04, 0.01, 0.05, respectively). Levels of specific IgE to SEA and SEB correlated significantly with levels of ECP and IL-5, but not those of tryptase or sIL-2R. CONCLUSION: These findings suggest that staphylococcal superantigens may drive local eosinophilic inflammation in nasal polyp tissue, and that this is exacerbated in subjects with AIA.     

IL-13 Gene Polymorphisms are Associated With Rhinosinusitis and Eosinophilic Inflammation in Aspirin Intolerant Asthma

Purpose

Aspirin-intolerant asthma (AIA) is characterized by moderate to severe asthma that is aggravated by aspirin or other non-steroidal anti-inflammatory drugs. Affected patients frequently have chronic rhinosinusitis and nasal polyposis due to persistent upper and lower airway inflammation with marked eosinophilia. IL-13 plays a crucial role in the development of allergic asthma by inducing airway eosinophilia and hyper-reactivity and it has been correlated with an increased eosinophil count.

Methods

Two promoter polymorphisms of the IL-13 gene (-1510 A>C and -1055C>T) and one coding nonsynonymus Arg110Gln (110G>A) polymorphism were genotyped using primer extension methods in 162 patients with AIA, 301 patients with aspirin-tolerant asthma (ATA), and 430 normal healthy controls (NC).

Results

There was no significant difference in the genotype, allele, and haplotype frequencies of the three polymorphisms among the three groups. AIA patients with the AA genotype -1510A>C (P=0.012) and CC genotype -1055C>T (P<0.001) had a significantly higher frequency of rhinosinusitis, as compared to those with the minor alleles of these two single nucleotide polymorphisms. AIA patients with the GG genotype had a higher peripheral eosinophil count (P=0.025) and a higher serum eotaxin-1 level (P=0.044), as compared to patients with the AA genotype IL-13 Arg110Gln (110G>A).

Conclusions

These findings suggest that the IL-13 polymorphisms at -1510A>C and 1055C>T are associated with the development of rhinosinusitis in AIA patients. IL-13 Arg110Gln may be associated with an increased eosinophil count and eotaxin-1 level and could increase eosinophilic inflammation in the upper and lower airways of patients with AIA.     

Clinical features of asthmatic patients with increased urinary leukotriene E4 excretion (hyperleukotrienuria): Involvement of chronic hyperplastic rhinosinusitis with nasal polyposis

BACKGROUND: The urinary leukotriene E4 (U-LTE4) concentration is significantly increased in patients with aspirin-intolerant asthma (AIA). However, the relationship between the clinicopathogenetic factors of asthma and the U-LTE4 concentration remains undetermined. OBJECTIVE: We sought to examine the clinical features of asthmatic patients with increased excretion levels of U-LTE4 (hyperleukotrienuria). METHODS: We measured the U-LTE4 concentrations in 137 asthmatic patients (including 64 patients with AIA) who were in clinically stable condition. A U-LTE4 concentration of 150 pg/mg creatinine or greater (mean U-LTE4 + 3 SDs of normal healthy control subjects) was indicative of hyperleukotrienuria. RESULTS: The basal concentration of U-LTE4 was significantly higher in the patients with AIA than in those with aspirin-tolerant asthma (ATA; median, 227.2 vs 90.3 pg/mg creatinine; P <.01). Compared with normal leukotrienuria in the patients with AIA, hyperleukotrienuria in the patients with AIA was associated with older age and decrease in pulmonary function. On the other hand, compared with normal leukotrienuria in the patients with ATA, hyperleukotrienuria in the patients with ATA was associated with severe asthma and chronic hyperplastic rhinosinusitis with nasal polyposis (CHRS/NP), which are well-known symptoms of the aspirin triad, as well as hypereosinophilia and anosmia. The patients with ATA with CHRS/NP excreted U-LTE4 at significantly high concentrations. There were significant decreases in the U-LTE4 concentrations before and after the sinus surgery in both the AIA and ATA groups (P <.05). CONCLUSION: Cysteinyl leukotrienes are not strictly associated with aspirin intolerance itself but rather with clinical features, such as CHRS/NP, that are similar to those seen in AIA. CHRS/NP might be involved in cysteinyl leukotriene overproduction in asthmatic patients.     

Association of SLC6A12 variants with aspirin‐intolerant asthma in a Korean population

Aspirin‐intolerant asthma (AIA) occurs from asthma exacerbation after exposure to aspirin. However, the underlying mechanisms of AIA occurrence are still unclear. The critical role of the solute carrier family 6 (neurotransmitter transporter, betaine/GABA) member 12 (SLC6A12) gene in GABAergic transmission, which is associated with mucus production in asthma, makes it a candidate gene for AIA association study. Eight single nucleotide polymorphisms (SNPs) in SLC6A12 were genotyped in 163 aspirin‐intolerant asthma (AIA) and 429 aspirin‐tolerant asthma (ATA) patients of Korean ethnicity. Associations between polymorphisms of SLC6A12 and AIA were analysed using multivariate logistic analysis. Results showed that two polymorphisms and a haplotype in SLC6A12, rs499368 (P= 0.005; P^corr= 0.03), rs557881 (non‐synonymous C10R, P= 0.007; P^corr= 0.04), and SLC6A12_BL1_ht1 (P= 0.009; P^corr= 0.05) respectively, were significantly associated with AIA after multiple testing corrections. In addition, SNPs of SLC6A12 were significantly associated with the fall rate of FEV₁ by aspirin provocation suggesting that SLC6A12 could affect reversibility of lung function abnormalities in AIA patients. Although these results are preliminary and future replications are needed to confirm these findings, this study showed evidence of association between variants in SLC6A12 and AIA occurrence among asthmatics in a Korean population.     

Association of β2-adrenergic receptor polymorphisms with severe asthma

BACKGROUND: There is considerable interest in the role of different candidate loci in the development of asthma. This study investigates the association between asthma severity and previously identified polymorphisms at two sites within the beta2-adrenergic receptor (beta2AR) gene: the Arg16-->Gly16 and Gln27-->Glu27 alleles. METHODS: Restriction enzyme analysis of amplified beta2AR gene products (PCR-RFLP) was used to analyse the frequency of the Arg16-->Gly16 and Gln27-->Glu27 polymorphisms within the beta2AR gene in 95 severe asthmatic patients (with a markedly increased risk of death from asthma), 59 mild asthmatic patients, and a control group of 92 nonasthmatic subjects. RESULTS: The Gly16 polymorphism was significantly associated with asthma severity with odds ratios (95% CI) for the Gly16 allele being 1.56 (1.02-2.40, P = 0.04) and 0. 98 (0.61-1.57, P = 0.92) for the severe and mild asthma groups, respectively. The corresponding odds ratios (95% CI) for Gly16 homozygotes were 1.91 (0.82-4.41, P = 0.13) and 0.82 (0.35-1.92, P = 0.65) for the severe and mild asthma groups, respectively. There was no significant association between either polymorphism at amino acid 27 and asthma or asthma severity. CONCLUSIONS: We conclude that the polymorphisms of amino acids 16 and 27 of the beta2AR gene are not associated with the development of asthma per se, but that the Gly16 polymorphism may play a role in the pathogenesis of asthma severity.     

Association of TNF-α genetic polymorphism with HLA DPB1*0301

BACKGROUND: We speculated TNF-alpha can be one of candidate gene for aspirin-intolerant asthma (AIA) because TNF-alpha is pro-inflammatory cytokine and known to be increased level in asthmatic airways. In addition, genetic interaction between TNF-alpha and human antigen leucocyte (HLA) DPB1*0301, which is a strong genetic marker for AIA, was examined for its close location within chromosome 6. METHOD: To investigate genetic association of TNF-alpha with an AIA phenotype, three study groups (163 patients with AIA, 197 patients with aspirin-tolerant asthma (ATA), 257 normal control subjects) were enrolled. Single nucleotide polymorphisms (SNPs) were genotyped using a single-base extension method and HLA DPB1 genotyping was determined by high-throughput sequencing method. RESULTS: All five SNPs of TNF-alpha were tested; there were no significant differences in allele and genotype frequencies among the three groups. However, significant association between TNF-alpha-308G>A polymorphism and atopy status was noted (P<0.05). Gene to gene interaction between TNF-alpha-1031T>C (or -863C>A or -857C>A) and HLA DPB1*0301could synergistically increase the susceptibility to AIA with odds ratio (OR) to 7.738 (or OR=8.184 for -863C>A, OR=7.500 for -857C>T, P<0.001, respectively). CONCLUSION: TNF-alpha promoter polymorphism may significantly increase susceptibility to AIA by gene-to-gene interaction with HLA DPB1*0301.     

Association analysis of C6 genetic variations and aspirin hypersensitivity in Korean asthmatic patients

There has been increasing evidence that genetic mechanisms contribute to the development of aspirin-intolerant asthma (AIA), a life-threatening disease. The complement component (C6) is a constituent of a biochemical cascade that has been implicated in airway epithelial damage and nasal polyposis, and therefore, may be a risk factor for AIA. To investigate the association between C6 variations and AIA in a Korean asthma cohort, 27 SNPs were selected for genotyping based on previously reported polymorphisms in the HapMap database. Genotyping was carried out using TaqMan assay, and five major haplotypes were obtained in 163 AIA cases and 429 aspirin-tolerant asthma (ATA) controls subjects. Genotype frequency distributions of C6 polymorphisms and haplotypes were analyzed using logistic and regression models. Subsequent analyses revealed a lack of association between C6 genetic variations and AIA. From the initial analyses, marginal associations of rs10512766 (p = 0.04 in co-dominant model) and rs4957374 (p = 0.05 in dominant model) with AIA did not reach the threshold of significance after multiple testing corrections; thus this study failed to find convincing evidence that variations in C6 gene influence the risk of AIA in a Korean population. However, these preliminary results may contribute to the etiology of aspirin hypersensitivity in Korean asthmatic patients.     

Transforming growth factor-β2 polymorphisms are associated with childhood atopic asthma

BACKGROUND: Transforming growth factor (TGF)-beta plays an important role in the regulation of airway inflammation and remodelling in asthma. Recent studies suggest that TGF-beta(2) is a predominant isoform expressed in severe asthma and it is also associated with airway remodelling. OBJECTIVE: To determine whether the polymorphisms in TGF-beta(2) are associated with childhood atopic bronchial asthma in a Japanese population. METHODS: We identified a total of eight polymorphisms and characterized the linkage disequilibrium (LD) mapping of the gene. Three variants in the promoter and 3'UTR were genotyped, and we conducted an association study of TGF-beta(2) (childhood atopic asthma n=297, normal controls n=555). An association analysis of these variants and an expression and functional analysis were performed. RESULTS: 3'UTR 94862T >A was found to be significantly associated with the risk of childhood atopic asthma (P=0.00041). The -109-->ACAA ins promoter variant was also associated with the risk of childhood atopic asthma (P=0.0037). TGF-beta(2) expression was observed in both the normal and asthmatic bronchial epithelium, and both real-time PCR and an ELISA showed a significant basal and TGF-beta(1)-induced TGF-beta(2) expression in the bronchial epithelial cell line BEAS2B. Furthermore, the promoter variant -109-->ACAA ins increased the TGF-beta(2) promoter-reporter activity in BEAS2B cells. CONCLUSIONS: Our data suggest that TGF-beta(2) may therefore be involved in the development of childhood atopic asthma by means of functional genetic polymorphism. The polymorphisms in TGF-beta(2) may become important information for asthma susceptibility in children.     

UBE3C genetic variations as potent markers of nasal polyps in Korean asthma patients

The human ubiquitin protein ligase E3C (UBE3C) regulates airway inflammatory responses and is hypothesized to be associated with the presence of nasal polyps in asthma-related diseases. A total of 24 UBE3C single-nucleotide polymorphisms (SNPs) were genotyped in a 467 Korean asthma cohort that was stratified into more homogenous phenotypes of 114 aspirin-exacerbated respiratory disease subgroup and 353 aspirin-tolerant asthma (ATA) subjects. Association analysis revealed that 16 UBE3C SNPs were significantly associated with presence of nasal polyps in the overall asthma group (P=0.0008 and P(corr)=0.01; odds ratio (OR)=0.60). The strength of association from 10 polymorphisms was increased in the ATA subgroup (P=0.0002 and P(corr)=0.003; OR=0.49). In addition, UBE3C_ht1 was found to be consistently associated with nasal polyps in the overall asthmatics group (P=0.006) and the ATA phenotype (P=0.002; P(corr)=0.02) via a codominant mechanism. Our findings provide evidence that variations in UBE3C are potent genetic markers of nasal polyps development in Korean asthmatics and may contribute novel insights into the clinical relevance and potential involvement of UBE3C in respiratory deficiencies.     

Association of angiotensin I‐converting enzyme gene polymorphisms with aspirin intolerance in asthmatics

Background Aspirin‐intolerant asthma (AIA) refers to the development of bronchoconstriction in asthmatic individuals following the ingestion of aspirin or other non‐steroidal anti‐inflammatory drugs (NSAIDs). Angiotensin I‐converting enzyme (ACE), a membrane‐bound peptidase present in the lung, plays a pivotal role in the metabolism of the endogenous peptides involved in the pathogenesis of asthma. Methods We screened a Korean asthma cohort (581 asthmatics including 81 aspirin‐intolerant asthmatics and 231 aspirin‐tolerant asthmatics, and 181 normal controls) for four single nucleotide polymorphisms (SNPs; ?262 A>T and ?115 T>C in the 5′‐flanking region and +5467 T>C [Pro450Pro] and+11860 A>G [Thr776Thr] in the coding region) and one ins/del (+21288 CT) in the ACE gene. Results None of the SNPs or haplotypes showed any association with the development of asthma, but they were significantly associated with the risk of AIA. Logistic regression indicated that the frequency of the rare alleles of ?262 A>T and ?115 T>C was higher in subjects with AIA than in subjects with aspirin‐tolerant asthma (ATA) (P=0.003–0.01, P ^corr=0.015–0.05). Subjects homozygous for the rare alleles of ?262 A>T and ?115 T>C showed a greater decline in forced expiratory volume in 1 s (FEV₁) after aspirin provocation than those homozygous for the common alleles (P<0.05). A luciferase reporter assay indicated that ACE promoters containing the rare ?262 A>T allele possessed lower activity than did those containing the common allele (P=0.009). In addition, ACE promoters bearing the rare ?115 T>C allele had no luciferase activity. DNA–protein binding assays revealed a band containing the ACE promoter region (including ?262 A) and a protein complex. Conclusion The ?262 A>T polymorphism in the promoter of the ACE gene is associated with AIA, and the rare allele of ?262 A>T may confer aspirin hypersensitivity via the down‐regulation of ACE expression.