Aspirin-tolerant Asthma Group Research Articles

Long-term clinical outcomes of aspirin-exacerbated respiratory disease: Real-world data from an adult asthma cohort.

Aspirin-exacerbated respiratory disease (AERD) is a phenotype of severe asthma, but its disease course has not been well documented compared with that of aspirin-tolerant asthma (ATA). This study aimed to investigate the long-term clinical outcomes between AERD and ATA. AERD patients were identified by the diagnostic code and positive bronchoprovocation test in a real-world database. Longitudinal changes in lung function, blood eosinophil/neutrophil counts, and annual numbers of severe asthma exacerbations (AEx) were compared between the AERD and the ATA groups. Within a year after baseline, two or more severe AEx events indicated severe AERD, whereas less than two AEx events indicated nonsevere AERD. Among asthmatics, 353 had AERD in which 166 and 187 patients had severe and nonsevere AERD, respectively, and 717 had ATA. AERD patients had significantly lower FEV1%, higher blood neutrophil counts, and higher sputum eosinophils (%) (all p < .05) as well as higher levels of urinary LTE4 and serum periostin, and lower levels of serum myeloperoxidase and surfactant protein D (all p < .01) than those with ATA. In a 10-year follow-up, the severe AERD group maintained lower FEV1% with more severe AEs than the nonsevere AERD group. We demonstrated that AERD patients presented poorer long-term clinical outcomes than ATA patients in real-world data analyses.

Increased expression of serine palmitoyl transferase and ORMDL3 polymorphism are associated with eosinophilic inflammation and airflow limitation in aspirin-exacerbated respiratory disease.

BackgroundPatients with aspirin-exacerbated respiratory disease (AERD) are known to have poor clinical outcomes. The pathogenic mechanisms have not yet been completely understood.ObjectiveWe aimed to assess the involvement of the de-novo synthetic pathway of sphingolipid metabolism in patients with AERD compared to those with aspirin tolerant asthma (ATA).MethodsA total of 63 patients with AERD and 79 patients with ATA were enrolled in this study. Analysis of mRNA expression of serine palmitoyl transferase, long-chain base subunit 2 (SPTLC2) and genotyping of ORMDL3 SNP (rs7216389) was performed.ResultsSignificantly higher levels of SPTLC2 mRNA expression were noted in patients with AERD, which showed significant positive correlations with peripheral/sputum eosinophil counts and urine LTE4 (all P<0.05). The levels of SPTLC2 mRNA expression showed significant negative correlations with the level of FEV1 and FEV1/FVC (P = 0.033, r = −0.274; P = 0.019, r = −0.299, respectively). Genotype frequencies of ORMDL3 SNP (rs7216389) showed no significant differences between the AERD and ATA groups. Patients with AERD carrying the TT genotype of ORMDL3 had significantly lower levels of FVC (%) and PC20 methacholine than those carrying the CT or CC genotype (P = 0.026 and P = 0.030).Conclusion & clinical relevanceThis is the first study that shows the dysregulated de novo synthetic pathway of sphingolipids may be involved in the eosinophilic inflammation and airflow limitation in AERD.

Epithelial folliculin enhances airway inflammation in aspirin-exacerbated respiratory disease.

Clinical features of aspirin-exacerbated respiratory disease (AERD) are characterized by overproduction of cysteinyl leukotrienes (LT) and eosinophil activation, in which epithelial cells contribute to eosinophilic airway inflammation. Folliculin (FLCN) helps maintain the integrity of epithelial barrier, but little is known about FLCN in AERD. We investigated the role of FLCN in the pathogenic mechanisms of AERD. We recruited 178 subjects with AERD, 276 subjects with aspirin-tolerant asthma (ATA) and 71 normal healthy controls (NC) at Ajou Medical Center. Levels of FLCN and interleukin (IL)-8 in sera and supernatants were measured by ELISA. Peripheral blood eosinophils isolated from asthmatic patients were cocultured with human airway epithelial cells (HAECs) pretreated with LTE4 , dexamethasone and montelukast. The intracellular expressions of FLCN, tight (TJ) (occludins, claudin-1) and adherens (AJ) junctions (E-cadherin) were analysed by Western blotting. shRNA was used to down-regulate FLCN (shFLCN) in HAECs. Serum FLCN levels were significantly higher in AERD group than in ATA and NC groups (all P < 0.001). The cut-off value of 56.6 pg/mL was used to define the high FLCN phenotype (highFLCN). Asthmatic patients with highFLCN were associated with increased airway hyperresponsiveness to methacholine (P = 0.015). The serum FLCN level could discriminate AERD group from NC group with 82% sensitivity (AUC = 0.793, P < 0.001). When HAECs were exposed to LTE4 , FLCN release was increased significantly (P < 0.05), which were amplified along with disruption of TJ and AJ expressions when HAECs were cocultured with eosinophils and LTE4 (all P < 0.05); these effects were suppressed by dexamethasone and montelukast. FLCN knockdown reduced IL-8 release and occludin expression from shFLCN HAECs. Our findings suggest that high LT and airway eosinophilia increased FLCN release from HAECs, which enhance epithelial activation and disruption. Modulation of FLCN may be a potential target for AERD.

Association ofTLR3gene polymorphism with IgG subclass deficiency and the severity in patients with aspirin-intolerant asthma

Purpose: Toll-like receptor 3 (TLR3) recognizes to viral double-stranded RNA and is involved in antiviral defenses. A probable role of TLR3 gene variants in the pathogenesis of aspirin-intolerant asthma (AIA) has been suggested. AIA patients present more frequent asthma exacerbations in which respiratory viral infections could be an exacerbating factor. IgG subclass deficiency was commonly present with bronchial asthma. Based on previous findings, we investigated whether TLR3 variants could affect IgG3 subclass deficiency in AIA.Methods: We enrolled 279 AIA patients, 403 aspirin-tolerant asthma (ATA) patients, and 315 normal healthy controls (NC) in this study. TLR3 polymorphism at the promoter region -299698G>T was genotyped. The serum levels of IgG subclasses were determined by the single radial immunodiffusion method. Expressions of IgG3 and TLR3 on Epstein-Barr virus transformed-B cells isolated from asthmatic patients were evaluated by flow cytometry to investigate B-cell functions.Results: The TLR3 -299698 T allele was significantly associated with severity and IgG3 deficiency in the AIA group (P=0.044 and P=0.010, respectively), but not in the ATA group. IgG3 expression on B cells from asthmatics with IgG3 deficiency was significantly lower compared to those without (P=0.025). There was a positive correlation between IgG3 expression levels on B cells and serum IgG3 levels (r2=0.434, P=0.002).Conclusion: These results suggest that the TLR3 -299698G>T polymorphism may be associated with IgG3 subclass deficiency and severity in AIA. (Allergy Asthma Respir Dis 2016:4:264-270)

Association Analysis ofMember RAS Oncogene FamilyGene Polymorphisms with Aspirin Intolerance in Asthmatic Patients

Member RAS oncogene family (RAB1A), a member of the RAS oncogene family, cycles between inactive GDP-bound and active GTP-bound forms regulating vesicle transport in exocytosis. Thus, functional alterations of the RAB1A gene may contribute to aspirin intolerance in asthmatic sufferers. To investigate the relationship between single-nucleotide polymorphisms (SNPs) in the RAB1A gene and aspirin-exacerbated respiratory disease (AERD), asthmatics (n=1197) were categorized into AERD and aspirin-tolerant asthma (ATA). All subjects were diagnosed as asthma on the basis of the Global Initiative for Asthma (GINA) guidelines. AERD was defined as asthmatics showing 15% or greater decreases in forced expiratory volume in one second (FEV(1)) or naso-ocular reactions by the oral acetyl salicylic acid (ASA) challenge (OAC) test. In total, eight SNPs were genotyped. Logistic regression analysis identified that the minor allele frequency of +14444 T>G and +41170 C>G was significantly higher in the AERD group (n=181) than in the ATA group (n=1016) (p=0.0003-0.03). Linear regression analysis revealed a strong association between the SNPs and the aspirin-induced decrease in FEV(1) (p=0.0004-0.004). The RAB1A gene may play a role in the development of AERD in asthmatics and the genetic polymorphisms of the gene have the potential to be used as an indicator of this disease.

Clinical Significance of Immunoglobulin E Responses to Staphylococcal Superantigens in Patients with Aspirin-Exacerbated Respiratory Disease

Background: Previous studies have reported a higher prevalence of immunoglobulin E (IgE) specific for staphylococcal superantigens (SAg) in the nasal mucosa of patients with aspirin-exacerbated respiratory disease (AERD), associated with eosinophilic inflammation and leukotriene production. However, the role of SAg-specific IgE in the pathogenesis of AERD is not well understood. We evaluated the clinical significance of serum IgE specific for three types of SAg, namely staphylococcal enterotoxins A and B (SEA and SEB) and toxic shock syndrome toxin-1 (TSST-1) in AERD. Methods: We enrolled 147 patients with AERD confirmed by a lysine-acetyl salicylic acid bronchoprovocative test and compared them with 147 patients with aspirin-tolerant asthma (ATA) and 141 healthy controls (NC). The levels of serum total IgE and SAg-specific IgE were measured using an ImmunoCAP system. Other clinical parameters were analyzed retrospectively. Results: The prevalences of SEA-, SEB- and TSST-1-specific IgE in the AERD and ATA groups were significantly higher than those in the NC group (p < 0.05, respectively). The total IgE level was significantly higher in patients with AERD with high levels of SEA-specific IgE than in those with lower levels (p < 0.05), with significant positive correlations between total and SAE-specific IgE levels (p < 0.05). The PC₂₀ methacholine level was significantly lower in patients with AERD with high levels of SEA-specific IgE, while a significantly higher eosinophil count was noted in patients with AERD with high levels of SEB-specific IgE (p < 0.05, respectively). Conclusions: Specific IgE responses to SAg may increase the serum total IgE level, airway hyperresponsiveness and eosinophil activation, leading to more severe clinical symptoms in AERD.

Association analysis of tapasin polymorphisms with aspirin-exacerbated respiratory disease in asthmatics

Aspirin-exacerbated respiratory disease (AERD) is characterized by the development of airway obstruction in asthmatic individuals following the ingestion of aspirin or other nonsteroidal anti-inflammatory drugs. TAPBP (TAP-binding protein, tapasin) is upregulated by eicosanoids, which act as potent inflammatory molecules in aspirin-related reactions. Thus, functional alterations in the TAPBP gene may contribute toward AERD. We examined the relationship between the single nucleotide polymorphisms on the TAPBP gene and AERD. A group of asthmatic patients (n=1252) underwent the oral aspirin challenge. Oral aspirin challenge reactions were categorized into two groups as follows: 15% or greater decreases in forced expiratory volume in 1 s or naso-ocular and skin reactions (AERD), or 15% or less decreases in forced expiratory volume in 1 s without naso-ocular and skin reactions (aspirin-tolerant asthma). Five single nucleotide polymorphisms of the TAPBP gene were genotyped. Logistic regression analysis showed that the minor allele frequencies of TAPBP rs2071888 C>G (Thr260Arg) on exon 4 (P>0.05), which was in absolute linkage disequilibrium with rs1059288 T>C on 3'UTR, were significantly higher in the AERD group than in the aspirin-tolerant asthma group, and the P values remained significant after multiple comparisons (Pcorr=0.006, odds ratio: 1.37, 95% confidence interval: 1.11-1.69, additive model; Pcorr=0.009, odds ratio: 1.52, 95% confidence interval: 1.14-2.03, dominant model). Alpha-helical wheel plotting showed that 260Arg had greater hydrophilic helical property than 260Thr. TAPBP polymorphisms may play a role in the development of AERD.

Eosinophil activation and novel mediators in the aspirin‐induced nasal response in AERD

Eosinophil activation is the key feature of upper and lower airway inflammation in aspirin-exacerbated respiratory disease (AERD). To investigate the mechanism of eosinophil activation and identify novel inflammatory mediators using proteomics. Thirty-two asthmatic subjects were enrolled: 18 AERD patients who showed positive responses to the lysine-aspirin nasal provocation test (L-ASA NPT) and 14 aspirin-tolerant asthma (ATA) patients who showed negative responses to the L-ASA NPT (control group). Nasal lavage fluid (NLF) was collected before (baseline), at 10, 30 and 60min (early response), and at 3h (late response) after the L-ASA NPT. Eosinophil cationic protein (ECP) and cysteinyl leucotriene (CysLT) levels were measured using an ImmunoCAP system and ELISA respectively. To identify proteins involved in AERD, comparative proteomics was applied using NLFs collected before and after L-ASA NPTs in AERD patients. The clinical relevance of identified novel proteins was evaluated by ELISA using NLFs from the AERD and ATA groups. Eosinophil cationic protein and CysLT levels both increased significantly during the early response in AERD. ECP levels increased until the late response in AERD, while CysLT levels were not significantly increased during the late response. Proteomic analysis showed up-regulation of apolipoprotein A1 (ApoA1), α2-macroglobulin (α2M) and ceruloplasmin (CP), with significant increases in NLF of AERD patients, which was significantly higher in AERD patients with chronic rhinosinusitis. Significant correlations were noted between ECP and CysLT, ApoA1, α2M and CP levels during the early response in AERD patients. Eosinophil activation occurred in early and late responses after L-ASA NPT in upper airway mucosa of AERD patients, where ApoA1, α2M and CP as well as CysLT may be involved in eosinophilic inflammation.

Genetic association analysis of CIITA variations with nasal polyp pathogenesis in asthmatic patients

Nasal polyps are abnormal lesions arising mainly from the nasal mucosa and paranasal sinuses. Since the human classII, major histocompatibility complex, transactivator (CIITA) is a positive regulator of classII, major histocompatibility complex gene transcription, the CIITA gene is thought to be involved in the presence of nasal polyps in asthma and aspirin hypersensitive patients. To investigate the association between CIITA and nasal polyposis, 18single nucleotide polymorphisms (SNPs) were genotyped in 467asthmatics who were classified into 158aspirin-exacerbated respiratory disease (AERD) and 309aspirin-tolerant asthma (ATA) subgroups. Differences in the frequency distribution of CIITA variations between polyp-positive cases and polyp-negative controls were determined using logistic analyses. Initially, a total of 9CIITA variants were significantly associated with the presence of nasal polyps in the overall asthma, AERD and ATA groups [P=0.001-0.05, odds ratio (OR)=0.53-2.35 in the overall asthma group; P=0.01-0.02, OR=2.45-2.66 in the AERD group; P=0.001‑0.05, OR=0.45-2.61 in the ATA group using various modes of genetic inheritance]. One the variations (rs12932187) retained this association after multiple testing corrections (Pcorr=0.01) in the overall asthma group. In addition, two variations (rs12932187 and rs11074938) were associated with the presence of nasal polyps following multiple testing corrections (Pcorr=0.02and0.04, respectively) in the ATA group. These novel findings suggest that rs12932187 and rs11074938 may constitute susceptibility markers of inflammation of the nasal passages in asthma patients.

A Highly Sensitive and Specific Genetic Marker to Diagnose Aspirin-Exacerbated Respiratory Disease Using a Genome-Wide Association Study

The aim of the present study was to develop a diagnostic set of single-nucleotide polymorphisms (SNPs) for discriminating aspirin-exacerbated respiratory disease (AERD) from aspirin-tolerant asthma (ATA) using the genome-wide association study (GWAS) data; the GWAS data were filtered according to p-values and odds ratios (ORs) using PLINK software, and the 10 candidate SNPs most closely associated with AERD were selected, based on 100 AERD and 100 ATA subjects. Using multiple logistic regression and receiver-operating characteristic (ROC) curve analysis, eight SNPs were chosen as the best model for distinguishing between AERD and ATA. The relative risk for AERD in each subject was calculated based on the relative risk of each of the eight SNPs. Ten of the original 109,365 SNPs highly associated (filtered with p<0.001 and ORs) with the risk for AERD were selected. A combination model of the eight SNPs among the 10 SNPs showed the highest area under the ROC curve of 0.9. The overall relative risk for AERD based on the eight SNPs was significantly different between the AERD and ATA groups (p=2.802E-21), and the sensitivity and specificity were 78% and 88%, respectively. The candidate set of eight SNPs may be useful in predicting the risk for AERD.

The IL1B-511 Polymorphism (rs16944 AA Genotype) Is Increased in Aspirin-Exacerbated Respiratory Disease in Mexican Population

Aspirin exacerbated respiratory disease (AERD) is characterized by chronic hyperplastic rhinosinusitis, nasal polyposis, asthma, and aspirin sensitivity. The mechanisms which produce these manifestations of intolerance are not fully defined, current research focuses on cyclooxygenase 1 (COX-1) inhibition, metabolism of arachidonic acid, and the COX pathway to the lipoxygenase (LO) route, inducing increased synthesis of leukotrienes (LT). The biological plausibility of this model has led to the search for polymorphisms in genes responsible for proinflammatory cytokines synthesis, such as IL1B and IL8. We performed a genetic association study between IL8-251 (rs4073) and IL1B-511 (rs16944) polymorphisms in AERD, aspirin-tolerant asthma (ATA), and healthy control subjects. Using allelic discrimination by real-time PCR, we found statistically nonsignificant associations between AERD, ATA, and healthy control subjects for the GG and GA genotypes of IL1B (rs16944). Interestingly, the AA genotype showed an increased frequency in the AERD patients versus the ATA group (GF = 0.19 versus 0.07, p = 0.018, OR 2.98, and 95% CI 1.17–7.82). This is the first observation that IL1B polymorphisms are involved in AERD. Thus, future studies must investigate whether interleukin-1β is released in the airways of AERD patients and whether it relates to genetic polymorphisms in the IL1B gene.

Urinary tetranor-PGDM concentrations in aspirin-intolerant asthma and anaphylaxis

Urinary tetranor-PGDM concentrations in aspirin-intolerant asthma and anaphylaxis

Urinary concentrations of 15‐epimer of lipoxin A4 are lower in patients with aspirin‐intolerant compared with aspirin‐tolerant asthma

Although an abnormality in arachidonic acid metabolism may be responsible for aspirin-intolerant asthma (AIA), there is little knowledge about the concentrations of urinary lipoxin A(4) (LXA(4)) and the 15-epimer of LXA(4) (15-epi-LXA(4)) in relation to asthma severity in AIA subjects. The purpose of this study is to estimate urinary LXA(4) and the 15-epimer concentrations to investigate lipoxins in AIA. In this study, we examined AIA, aspirin-tolerant asthma (ATA) and healthy control groups. The AIA and ATA groups were subdivided into the severe asthma and non-severe asthma subgroups. Urinary LXA(4), 15-epi-LXA(4) and leukotriene E(4) (LTE(4) ) were quantified using enzyme immunoassay after separating these compounds using high-performance liquid chromatography. The urinary LXA(4) concentration was significantly lower than the 15-epi-LXA(4) concentration in the asthmatic subjects. The AIA group showed significantly lower urinary 15-epi-LXA(4) (P < 0.01) and higher urinary LTE(4) concentrations (P < 0.05) than the ATA group. Comparison of 15-epi-LXA(4) concentrations between the severe asthmatic and non-severe asthmatic subjects in the AIA and ATA groups revealed that the decreased 15-epi-LXA(4) concentration may be related to aspirin intolerance, but not asthma severity. Receiver operator characteristic curves demonstrated that the concentration ratio of LTE(4) to 15-epi-LXA(4) was superior to 15-epi-LXA(4) concentration and LTE(4) concentration as a predictive factor for aspirin intolerance. We have demonstrated for the first time that urinary 15-epi-LXA(4) concentration is significantly higher than LXA(4) concentration in both the AIA and ATA groups. 15-Epi-LXA(4) concentration was significantly lower in the AIA group with an increased urinary LTE(4) concentration than in the ATA group. An imbalance between proinflammatory cysteinyl-leukotrienes and anti-inflammatory 15-epi-LXA(4) may be involved in AIA pathogenesis.

Association Analysis of Thromboxane A Synthase 1 gene Polymorphisms with Aspirin Intolerance in Asthmatic Patients

Thromboxane A synthase (TBXAS1) converts prostaglandin H to thromboxane A, a potent constrictor of smooth respiratory muscle. Thus, functional alterations of the TBXAS1 gene may contribute to aspirin-intolerant asthma (AIA). We investigated the relationship between SNPs in the TBXAS1 gene and AIA. Asthmatics (n = 470) were categorized into AIA (20% or greater decreases in forced expiratory volume in 1 s [FEV(1)], or 15% to 19% decreases in FEV(1) with naso-ocular or cutaneous reactions) and aspirin-tolerant asthma (ATA). A total of 101 SNPs were genotyped. mRNA expression of the TBXAS1 gene by peripheral blood mononuclear cells and plasma thromboxane B2 (TXB2) concentrations were measured by reverse transcriptase (RT)-PCR and ELISA. Logistic regression analysis showed that the rare allele frequency of rs6962291 in intron 9 was significantly lower in the AIA group (n = 115) than in the ATA group (n = 270) (p(corr) = 0.04). The linear regression analysis revealed a strong association of rs6962291 with the aspirin challenge-induced FEV(1) fall (p = 0.003). RT-PCR revealed an exon-12-deleted splice variant. We measured TBXAS1 mRNA levels in peripheral blood mononuclear cells. The mRNA levels of the full-length wild-type and splice variant were significantly higher in the TT homozygotes than in the AA homozygotes of rs6962291 (1.00 ± 0.18 vs 0.57 ± 0.03 and 1.00 ± 0.18 vs 0.21 ± 0.05, p = 0.047 and 0.001, respectively). The plasma TXB2 level was significantly lower in rs6962291 AA carriers than in rs6962291 TT (p = 0.016) carriers. The rare allele of rs6962291 may play a protective role against aspirin hypersensitivity via a lower catalytic activity of the TBXAS1 gene, attributed to the increase of a nonfunctioning isoform of TBXAS1.

Association Analysis of N -Acetyl Transferase-2 Polymorphisms with Aspirin Intolerance Among Asthmatics

Cysteinyl leukotrienes are inactivated by acetyl coenzyme A-dependent N-acetyltransferase (NAT). Thus, functional alterations of the NAT gene may contribute to the risk of aspirin-intolerant asthma. Asthmatics (n = 438) were categorized into aspirin-intolerant asthma (15% or greater decrease in the forced expiratory volume in 1 s or cutaneous reactions, n = 170) or aspirin-tolerant asthma (n = 268) groups. In total, 14 polymorphisms of the NAT2 gene were genotyped by a single-base extension method. The distributions of all loci of the 14 SNPs were in Hardy-Weinberg equilibrium (p > 0.05). Among the 14 SNPs, six common SNPs (minor allele frequency >5%) in a Korean population were used for haplotype construction and further statistical analysis. The logistic regression analysis demonstrated that NAT2 -9246G>C and haplotype 2 (TCACGG) were significantly associated with the risk of aspirin-intolerant asthma. The rare allele frequencies of the SNP and Ht2 were significantly higher in the aspirin-intolerant asthma group than in the aspirin-tolerant asthma group (p(corr) = 0.03 and p(corr) = 0.02 in codominant model). In a large genetic epidemiology study of aspirin-intolerant asthma in a Korean population, genetic polymorphisms of NAT2 were found to be related to a risk of aspirin hypersensitivity among asthmatics.

Profile of eicosanoid generation in aspirin-intolerant asthma and anaphylaxis assessed by new biomarkers

It has recently demonstrated that a free radical-mediated pathway generates prostaglandins (PGs) and the corresponding prostaglandin enantiomers (ent-PGs). Aspirin-intolerant asthma and anaphylaxis accompany PGD(2) overproduction, possibly associated with mast cell activation via the COX pathway. However, free radical-mediated PG generation in the pathophysiology of these diseases, which can be demonstrated by measuring urinary ent-PGF(2)alpha, has not been reported. To evaluate the characteristic profile of eicosanoid generation via the COX and/or free radical-mediated pathway underlying aspirin-intolerant asthma and anaphylaxis. A comparative group analysis consisted of asthma (n = 17) and anaphylaxis (n = 8, none with aspirin-induced anaphylaxis) cases. Urinary eicosanoid concentrations were quantified as follows: 2,3-dinor-9alpha,11beta-PGF(2) by gas chromatography-mass spectrometry; leukotriene E(4), 9alpha,11beta-PGF(2), and PGs by enzyme immunoassay. 2,3-Dinor-9alpha,11beta-PGF(2) is a more predominant PGD(2) metabolite in urine than 9alpha,11beta-PGF(2). At baseline, the aspirin-intolerant asthma group (n = 10) had significantly higher leukotriene E(4) and lower PGE(2) concentrations in urine than the aspirin-tolerant asthma group. During the reaction, the urinary concentrations of leukotriene E(4) and PGD(2) metabolites correlatively increased, but with markedly different patterns of the mediator release, in the aspirin-intolerant asthma group and the anaphylaxis group, respectively. The urinary PGD(2) metabolites and primary PGs were significantly decreased in the aspirin-tolerant asthma group. Urinary ent-PGF(2)alpha concentrations were significantly increased in the anaphylaxis group but not the aspirin-intolerant asthma group. When assessed by urinary 2,3-dinor-9alpha,11beta-PGF(2), PGD(2) overproduction during aspirin-intolerant bronchoconstriction was clearly identified, regardless of COX inhibition. It is evident that free radical-mediated PG generation is involved in the pathophysiology of anaphylaxis.

Obesity in aspirin‐tolerant and aspirin‐intolerant asthmatics

Obesity is an important factor in the development of asthma. Aspirin hypersensitivity affects 5-10% of asthmatics. The association between obesity and aspirin hypersensitivity in asthma is unclear. This study evaluated the association of BMI and asthma in patients with aspirin-tolerant asthma (ATA) and aspirin-intolerant asthma (AIA). Aspirin provocation tests were performed in 667 asthmatic patients and changes in FEV(1) were used to categorize patients as ATA or AIA. The BMI of asthmatics was graded using the percentile BMI of 406 normal controls. Aspirin-induced changes in FEV(1)% ranged from 15% to 68%. Compared with the controls, the ATA group had a higher BMI (24.5 +/- 0.1 vs 23.8 +/- 0.2 kg/m(2), P = 0.001). The AIA group had a lower BMI. The aspirin-induced percentage fall in FEV(1) was inversely correlated with BMI in asthmatic patients (r = -0.094, P = 0.016). BMI was correlated with age and PC20, but not with FEV(1) in asthmatic patients. In a logistic regression adjusted for age, gender, and smoking status, FEV(1) and PC20 were associated with AIA with odds ratios of 0.986 and 0.586, respectively. BMI was associated with AIA with an odds ratio of 0.916. Aspirin intolerance in asthmatics explains the lesser association with obesity. Obesity is not a risk factor in the development of asthma in patients with AIA.

Alternative splicing of cyclooxygenase‐1 gene: altered expression in leucocytes from patients with bronchial asthma and association with aspirin‐induced 15‐HETE release

Cyclooxygenase-1 (COX-1) is a key enzyme involved in generation of prostanoids, important mediators and modulators of asthmatic inflammation. In a subpopulation of aspirin-sensitive asthmatics (ASA) inhibition of COX-1 by nonsteroidal anti-inflammatory drugs results in activation of inflammatory cells and development of symptoms. Alternatively spliced variants of COX-1 lacking 111 bp from exon 9 were described previously but have never been identified in human leucocytes peripheral blood leucocytes (PBL) or upper airway epithelial cells. We aimed to assess the expression of spliced variants of COX-1 mRNA in PBLs from patients with asthma and in healthy subjects (HS) referring the expression to patients characteristics (including ASA-sensitivity) and to aspirin-triggered 15-hydroxyeicosatetraenoic acid (15-HETE) generation. The study included 30 patients with ASA, 30 patients with aspirin-tolerant asthma (ATA) and 30 HS serving as controls. Nasal polyps for epithelial cell cultures were obtained from 10 patients with chronic rhinosinusitis. Expression of full length and spliced variants of COX-1 enzyme was detected by RT-PCR and presented as the ratio of full-length COX-1 to alternatively spliced COX-1 mRNA [COX-1 alternative splicing index (COX-1 AS index)]. Release of eicosanoids (PGE(2) and 15-HETE) by PBLs was measured with enzyme immunoassay. In both PBLs and airway epithelial cells the expression of full-length product prevailed over spliced variants of COX-1 enzyme. Cyclooxygenase-1 AS index was significantly lower in asthmatics as compared to HS (1.96 +/- 0.71 vs 2.41 +/- 0.99, P < 0.05) indicating the relatively higher expression of the alternative transcript in asthmatic patients. Cyclooxygenase-1 AS index was not different between ASA and ATA groups (mean 1.90 +/- 0.66 vs 2.02 +/- 0.76, respectively, P = 0.39). There was no significant association between COX-1 AS index and mean daily dose of inhaled glucocorticosteroids or pulmonary function tests (FEV(1), FVC) but in ASA group a weak correlation with daily dose of oral glucocorticosteroids was found (r = 0.39; P = 0.03). In ASA patients there was a significant positive correlation between the COX-1 AS index and the percentage of aspirin-triggered increase in 15-HETE generation (r = 0.51; P < 0.03). Alternatively spliced variants of COX-1 mRNA are differently expressed in patients with bronchial asthma and may be associated with aspirin-triggered 15-HETE generation.

ADAM33 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.

Comparison of Plasma Eotaxin Family Level in Aspirin-Induced and Aspirin-Tolerant Asthma Patients

Eosinophilic infiltration of airway tissue is a central feature of aspirin-induced asthma (AIA). Eotaxins belong to the family of CC chemokines, which coordinate the recruitment of inflammatory cells bearing chemokine (C-C motif) receptor-3 to sites of allergic inflammation. In the present study, the levels of eotaxin-1, eotaxin-2, and eotaxin-3 following an oral aspirin provocation test (APT) were measured, and the relationship between the eotaxin level and clinical parameters in patients with asthma was evaluated. An APT was performed in patients with asthma. Twenty AIA patients and 23 aspirin-tolerant asthma (ATA) patients were identified. Plasma levels of eotaxin-1, eotaxin-2, and eotaxin-3 levels were measured by enzyme-linked immunosorbent assay in the 43 patients with asthma and in 39 control subjects. The proportion of blood eosinophils was significantly higher in asthmatic patients than in control subjects. Nasal polyps were more common in AIA patients than in ATA patients (p < 0.05). In addition, the eotaxin-1 level was higher in AIA and ATA patients than in control subjects (p < 0.01 for each). The eotaxin-2 level was higher in ATA patients than in either the AIA patients (p < 0.05) or control subjects (p < 0.01). Similarly, the eotaxin-3 level was higher in ATA patients than in control subjects. A trend toward higher plasma levels of eotaxin-1 and eotaxin-3 at baseline and at 4 h after APT administration in the ATA group was noted but was not significant. Eotaxin-2 was also higher in ATA patients than in AIA patients at baseline and at 4 h after the APT. This study shows that eotaxin-2 is differentially secreted in patients with asthma according to aspirin intolerance, and that secretion is not time-dependent in response to the APT in AIA and ATA patients. It therefore appears that eotaxin-2 may be up-regulated and may act differentially in patients with ATA.