Aspirin-tolerant Asthma Subjects Research Articles

Elevation of Eosinophil-Derived Neurotoxin in Plasma of the Subjects with Aspirin-Exacerbated Respiratory Disease: A Possible Peripheral Blood Protein Biomarker

Aspirin-exacerbated respiratory disease (AERD) remains widely underdiagnosed in asthmatics, primarily due to insufficient awareness of the relationship between aspirin ingestion and asthma exacerbation. The identification of aspirin hypersensitivity is therefore essential to avoid serious aspirin complications. The goal of the study was to develop plasma biomarkers to predict AERD. We identified differentially expressed genes in peripheral blood mononuclear cells (PBMC) between subjects with AERD and those with aspirin-tolerant asthma (ATA). The genes were matched with the secreted protein database (http://spd.cbi.pku.edu.cn/) to select candidate proteins in the plasma. Plasma levels of the candidate proteins were then measured in AERD (n = 40) and ATA (n = 40) subjects using an enzyme-linked immunosorbent assay (ELISA). Target genes were validated as AERD biomarkers using an ROC curve analysis. From 175 differentially expressed genes (p-value <0.0001) that were queried to the secreted protein database, 11 secreted proteins were retrieved. The gene expression patterns were predicted as elevated for 7 genes and decreased for 4 genes in AERD as compared with ATA subjects. Among these genes, significantly higher levels of plasma eosinophil-derived neurotoxin (RNASE2) were observed in AERD as compared with ATA subjects (70(14.62∼311.92) µg/ml vs. 12(2.55∼272.84) µg/ml, p-value <0.0003). Based on the ROC curve analysis, the AUC was 0.74 (p-value = 0.0001, asymptotic 95% confidence interval [lower bound: 0.62, upper bound: 0.83]) with 95% sensitivity, 60% specificity, and a cut-off value of 27.15 µg/ml. Eosinophil-derived neurotoxin represents a novel biomarker to distinguish AERD from ATA.

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.

PGE2 suppresses excessive anti‐IgE induced cysteinyl leucotrienes production in mast cells of patients with aspirin exacerbated respiratory disease

Aspirin causes bronchospasm in patients with aspirin exacerbated respiratory disease (AERD). The contribution of mast cells to the increased cysteinyl-leucotrienes (cys-LTs) detected in AERD patients is however not defined. Effects of prostaglandin (PG) E(2) and inhibitors of cyclooxygenase (COX) and lipoxygenase (LO) pathways on mediator release from cultured mast cells of normal subjects, aspirin tolerant asthma (ATA) and AERD patients were compared to better define the role of mast cells in AERD. Mast cells were cultured from peripheral blood progenitors and were activated by anti-IgE. Histamine, PGD(2) and cys-LTs released were then determined. Basal release of all three mediators was similar in all subjects. Although the release of all three mediators was increased by anti-IgE, mast cells from AERD patients produced significantly more cys-LTs (6.9 +/- 2.0 ng/10(6) cells) than normal and ATA subjects (2.3 +/- 0.8 and 1.7 +/- 0.5 ng/10(6) cells, respectively). While COX and LO pathway inhibitors did not affect anti-IgE induced histamine release, they significantly suppressed the production of PGD(2) and cys-LTs, respectively, in all patients. PGE(2) significantly enhanced anti-IgE induced histamine and PGD(2) release from mast cells of normal subjects but not those of ATA and AERD patients. In contrast, PGE(2) suppressed only anti-IgE induced cys-LTs release from mast cells of AERD patients. We speculate that overproduction of cys-LTs is unique to mast cells of AERD patients and is particularly sensitive to suppression by PGE(2). Consequently reduction of PGE(2) production by aspirin removes this endogenous control of cys-LTs overproduction, resulting in asthma attack.

Role of staphylococcal superantigen-specific IgE antibodies in aspirin-intolerant asthma

IgE antibodies specific for staphylococcal superantigens (SAg) have been implicated in the pathology of several allergic diseases such as rhinosinusitis, nasal polyposis, asthma, and aspirin intolerance. We sought to determine whether SAg-specific IgE levels associate with clinical parameters in patients with aspirin-intolerant asthma (AIA), as compared with patients with aspirin-tolerant asthma (ATA) and nonatopic controls. Eighty patients with AIA, 62 patients with ATA, and 52 normal controls were enrolled in this study. Total serum IgE and IgE specific for staphylococcal enterotoxin A, staphylococcal enterotoxin B, and staphylococcal toxic shock syndrome toxin 1 (TSST-1) were measured using the CAP system (Pharmacia, Uppsala, Sweden). The prevalence of staphylococcal enterotoxin B-specific IgE and TSST-1-specific IgE was significantly higher in the asthma patients than in the healthy controls. The prevalence of SEB-specific IgE was slightly higher in patients with AIA than in those with ATA (22.5% versus 14.5%), although this difference was not statistically significant. No significant difference in staphylococcal enterotoxin A-specific or TSST-1-specific IgE was found between AIA and ATA subjects. Total serum IgE levels were higher in asthma patients with detectable SAg-specific serum IgE than in those without. Airway hyperresponsiveness, as measured by PC20 methacholine, was significantly increased in asthma patients with detectable SAg-specific IgE than in asthma patients without (p = 0.038). There were no significant differences in other clinical parameters between AIA and ATA patients with and without detectable SAg-specific antibody responses. These findings suggest that the staphylococcal SAg may contribute to airway inflammation and the development of airway hyperresponsiveness in asthma.