Dual Asthmatic Response Research Articles

Response of upper and lower airway inflammation to bronchial challenge with house dust mite in Chinese asthmatics: a pilot study.

BackgroundAllergen nasal challenge can induce increase of eosinophils in sputum, but report about eosinophilic inflammation in upper airway after allergen bronchial challenge in Chinese asthmatics was rare. The article aims to evaluate response of upper and lower airways to house dust mite (HDM) allergen bronchial challenge.MethodsHDM allergen bronchial challenge was carried out in asthmatic patients with allergic rhinitis (AR). Bronchial methacholine challenge and blood test were performed before and at 24 hours after allergen challenge. Nasal lavage and induced sputum for differential cells count and fractional exhaled nitric oxide (FeNO) measurement were performed before, 7 and 24 hours after allergen challenge.ResultsEighteen asthmatic patients with AR underwent HDM allergen bronchial challenge with no serious adverse events reported. Fifteen patients showed dual asthmatic response (DAR), while 2 patients showed early (EAR) and 1 late asthmatic response (LAR) only. At 24 hours after allergen bronchial challenge testing, average PC20FEV1 to methacholine significantly decreased (1.58 to 0.81 mg/mL, P=0.03), while both FeNO and the percentage of eosinophils in blood and sputum were significantly increased [52.0 (54.0) to 69.0 (56.0) ppb, P=0.01; 4.82% to 6.91%, P<0.001; 20.70% to 27.86%, P=0.03, respectively], but with no significant differences found in the percentage of eosinophils in nasal lavage (39.36% to 38.58%, P=0.89). However, at 7 hours after allergen challenge, the eosinophils in sputum were significant increased to 40.45% (P<0.001), but there was an increase (39.36% to 48.07%) with no statistical difference (P=0.167) found in nasal lavage.ConclusionsHDM allergen bronchial challenge induced different response of airway inflammation in upper and lower airways.

P135 Prevalence Of Sensitisation To Soya Flour In The Baking Industry Within The Uk

Introduction Soya flour is routinely used as a baking additive to increase shelf life, improve colour and introduce a nutty flavour to bread. Although a large number of bakers are exposed to soya flour, there is little information as to the prevalence of sensitisation to soya flour in the baking industry. One study reports sensitisation to soya flour in four bakers who were sensitised to flour and alpha amylase and a bronchial challenge to soya flour elicited an immediate or dual asthmatic response. Studies in soy processing plant (slightly different to bakeries) report soy-specific IgE in 21% of soy processing workers compared with only 4% in health care workers, suggesting soya is an important occupational allergen in the soy processing industry. Methods To determine prevalence of sensitisation to soya flour in bakery workers, we carried out skin prick testing to soya flour (Allergopharma 598) in bakery workers exposed to soya flour (n = 196) and in non-bakery controls (n = 50), who attended an occupational lung disease clinic. Skin tests were categorised as positive if they induced a wheal with a mean diameter of ≥2 mm greater than the response to a negative (saline) control and histamine was used as a positive control. Results In a total of one hundred and ninety five bakery workers exposed to soya, forty two bakers were sensitised to soya flour (21%), and forty of those bakers were also sensitised to either flour and or alpha amylase (95%) In comparison, none of the control group (n = 50) were sensitised to soya flour. Conclusion In our preliminary study of bakery workers exposed to soya flour, we found that around a fifth of the population were sensitised to soya flour. The clinical significance of soya flour need further investigation, although it seems prudent to include soya flour in the diagnostic tests for bakers asthma.

Th17/Treg ratio derived using DNA methylation analysis discriminates allergen-induced early from dual asthmatic responses

Background Atopic allergic asthmatic individuals experience acute bronchoconstriction (early response) upon allergen exposure. Several hours after the initial exposure, some individuals exhibit a chronic late phase (dual responders, DRs) whereas others do not (early responders, ERs). The purpose of this study is to determine changes in Th17 and regulatory T (Treg) cell numbers and their associated gene expression profiles in whole blood between allergen-induced ERs and DRs. Methods 14 participants with mild, atopic asthma (8 ERs and 6 DRs) underwent a cat allergen inhalation challenge as part of the AllerGen Clinical Investigator Collaborative. Whole blood was collected immediately prior to challenge (pre) and 2 hours post-challenge. DNA methylation analysis was used to measure the frequency of Th17, Treg, B and T cells (Epiontis, Germany). Whole blood transcriptome profiling was performed using Affymetrix GeneChip ® Human Gene 1.0 ST Arrays. Statistical analysis was performed using R. Results Sum of the T cell and B cell frequencies obtained using the methylation assays strongly correlated (r = 0.95) with the lymphocyte frequency obtained using a hematolyzer. Allergen inhalation did not significantly (p>0.05) change Th17, Treg, B and T cell counts between ERs and DRs. However, the Th17/Treg ratio was significantly (p=0.03) different between ERs and DRs post challenge. 199 genes positively correlated with Th17 cells at an FDR of 5%. 463 genes positively correlated with Treg cells at an FDR of 5%. Th17 genes were inversely correlated with Treg genes. Conclusions Th17/Treg ratio derived using DNA methylation analysis discriminates allergen-induced early from dual asthmatic responses. The inverse correlation between Th17 genes and Treg genes may be indicative of the inflammatory or suppressive phenotypes of these cells.

Occupational asthma induced by beat-galactosidase

Galactosidase is generated from Aspergillus oryzae, which is widely used for antidiarrhea medicine to infants. Antibiotics and digestives were reported as a causative allergen inducing occupational asthma. Galatosidase-induced occupational asthma has not been reported yet. A forty-year-old female has suffered from rhinorrhea, sneezing, and nasal obstruction 1 year after handling galactosidase at obstetric and pediatric hospital, and then dyspnea appeared later. Skin prick test with inhalent allergens, beta-galactosidase, and Aspergillus oryzae showed strong positive reaction to beta-galactosidase only. Immunoinhibition test with beta-galactosidase and A. oryzae revealed inhibition to beta-galactosidase only. Bronchial provocation test with beta-galactosidase showed the dual asthmatic response. With these results, we confirmed that the patient has beta-galactosidase-induced occupational asthma and rhinitis. (Allergy Asthma Respir Dis 2014;2:75-77)

Effects of inhaled corticosteroids on the dual asthmatic response

Bronchial asthma patients develop various asthmatic response types to allergen challenge, such as immediate asthmatic response (IAR), late asthmatic response (LAR), or dual asthmatic response (DAR), the latter being a combination of an early phase (IAR) and a late phase (LAR). This study was designed to investigate (1) the features of the DAR thus identifying it as either a genuine two-phase compact clinical entity or a simultaneous appearance of two independent asthmatic response types, IAR and LAR, and (2) the protective effects of inhaled budesonide (BUD) on the DAR. Two protection tests (PTs) with BUD and a placebo (PL), in a single dose of 800 micrograms, were performed on 48 DAR patients, divided into four groups. Each test consisted of two treatments, one given 30 minutes before and the other at 1, 2, 3, or 4 hours after the bronchial challenge with allergen. The study design was randomized, double-blind, double-dummy, placebo-matched, crossover. A single dose of inhaled BUD did not affect the early phase (IAR) when applied 30 minutes before the challenge (p > 0.2), whereas it significantly prevented the late phase (LAR) when administered either 30 minutes before (p < 0.001) or up to 4 hours after the allergen challenge (p < 0.05). The different protective effects of BUD on both of the phases of DAR would suggest that this response does not exist as a compact clinical entity, but it may be a manifestation of two independent simultaneous responses, IAR and LAR, because of different immunologic mechanisms. Inhaled corticosteroids in a single dose administered shortly before or up to 4 hours after the allergen exposure contribute significantly to the prevention of the LAR, whereas they are unable to affect the IAR.

Gene-Metabolite Expression in Blood Can Discriminate Allergen-Induced Isolated Early from Dual Asthmatic Responses

Some asthmatic individuals undergoing allergen inhalation challenge develop an isolated early response whereas others develop a dual response (early plus late response). In the present study we have used transcriptomics (microarrays) and metabolomics (mass spectrometry) of peripheral blood to identify molecular patterns that can discriminate allergen-induced isolated early from dual asthmatic responses. Peripheral blood was obtained prior to (pre-) and 2 hours post allergen inhalation challenge from 33 study participants. In an initial cohort of 14 participants, complete blood counts indicated significant differences in neutrophil and lymphocyte counts at pre-challenge between early and dual responders. At post-challenge, significant genes (ALOX15, FADS2 and LPCAT2) and metabolites (lysolipids) were enriched in lipid metabolism pathways. Enzymes encoding for these genes are involved in membrane biogenesis and metabolism of fatty acids into pro-inflammatory and anti-inflammatory mediators. Correlation analysis indicated a strong negative correlation between ALOX15, FADS2, and IL5RA expression with 2-arachidonoylglycerophosphocholine levels in dual responders. However, measuring arachidonic acid and docosahexaenoic acid levels in a validation cohort of 19 participants indicated that the free form of DHA (nmoles/µg of protein) was significantly (p = 0.03) different between early and dual responders after allergen challenge. Collectively these results may suggest an imbalance in lipid metabolism which dictates pro- (anti-) inflammatory and pro-resolving mechanisms. Future studies with larger sample sizes may reveal novel mechanisms and therapeutic targets of the late phase asthmatic response.

Occupational asthma due to polyvinyl chloride and methylmethacrylate, “hidden in an adhesive”

Polyvinyl chloride (PVC) is a thermoplastic polymer widely used in industry, reflected in the number of tons consumed annually in the world. We present a 48 year old male patient with no history of atopy, plumber by profession for 30 years, developed progressive dyspnea and dry cough in the last 3 years, triggered in the work environment and persist outside it, related it to manipulate an adhesive called Tangit, whose components are PVC powder and methylmethacrylate. Never presented skin lesions, or used protection. Were performed blood tests, chest radiography, skin tests, spirometry, bronchodilator test and fraction of exhaled nitric oxide, methacholine challenge test was positive (PC 20, 8 mg/dl). After signing informed consent, we performed specific bronchial provocation (SBP) in a 7m 3 dynamic chamber for 30 minutes of cumulative exposure, simulating working conditions with placebo, the Tangit adhesive provoked a late asthmatic response with a maximal fall in FEV1 of 33% at 7 hours, PVC powder and methylmethacrylate generated dual asthmatic responses, with a maximum drop of 17% at 30 minutes and 17.3% at 7 hours, 22% at 2 minutes and 20% at 9 hours, respectively. The patient during the study was on sick leave from to 24 months. We report a case of occupational asthma by PVC and methylmethacrylate, shown by specific bronchial challenge in a plumber exposed to these agents. There are cases of occupational asthma published by the degradation products of PVC or manipulated workers manufacturing bottle caps1 and packaging. It is the first case of occupational asthma by PVC content in an adhesive. So far been known that adhesives containing acrylates, capable of inducing asthma.

Occupational asthma caused by inhaling smoke from roasting perilla seeds

Perilla is an Asian grain that consumed for food ingredient, oil crops, medicinal materials through the process of roasting. A 49-year-old male has been roasting grains for 10 years, who met with shortness of breath during the roasting perilla seeds, but not in other situations. Serum total immunoglobulin E (IgE) level, serum eosinophil count and skin prick test didn`t showed significant results. Methacholine bronchial provocation test was positive (PC20 0.31 mg/mL). Specific bronchial provocation test with inhaling smoke from roasting perilla seeds showed a dual asthmatic response. Measured peak expiratory flow rate on his work place showed the result of 37% decrease at the end of work and full recovery at 6 hours after the end of work. Skin prick test to row perilla showed positive response with late symptoms. We diagnosed that the patient had an occupational asthma caused by inhaling smoke from roasting perilla seeds with IgE mediated mechanism. (Allergy Asthma Respir Dis 1(1):90-93, 2013)

Peripheral Blood Th17 Cells and Neutrophils in Dermatophagoides pteronyssinus-induced Early- and Late-Phase Asthmatic Response

Biphasic cellular immune reactions, which follow allergen inhalation, are a specific feature of inflammation in allergic asthma. The aim of this study was to determine the changes in the percentage of peripheral blood Th17 cells and neutrophil functions after Dermatophagoides pteronyssinus-induced early- and late-phase asthmatic response in patients with allergic asthma. A total of 19 patients with allergic asthma were examined. Eleven patients developed an isolated early-phase asthmatic response (EAR), whereas 8 developed both early- and late-phase (dual) asthmatic responses (DAR) after the bronchial challenge with Dermatophagoides pteronyssinus. The control group included 15 healthy subjects. Peripheral blood collection was performed 24 hours before as well as 7 and 24 hours after the bronchial challenge. The percentage of Th17 cells, and chemotaxis and apoptosis of neutrophils were analyzed by flow cytometry. The serum IL-8 and IL-17 levels were determined by ELISA. After the bronchial challenge, the percentage of Th17 and IL-17 levels increased considerably 7 and 24 hours after the challenge in both groups of patients. Moreover, 24 hours after the challenge, the percentage of Th17 cells and IL-17 levels were significantly higher in the patients with the DAR than those with the EAR or healthy controls. Seven and 24 hours after the challenge, neutrophil chemotaxis was greater in the patients with the DAR as compared with those with the EAR and healthy controls as well. The apoptotic activity of neutrophils was lower 24 hours after the challenge in the patients with the DAR than those with the EAR. Dermatophagoides pteronyssinus-induced early- and late-phase asthmatic response in patients with allergic asthma was found to be accompanied by an increased percentage of peripheral blood Th17 cells and elevated serum IL-17 levels as well as altered neutrophil functions.

Airway Inflammatory Responses Following Exposure to Occupational Agents

Airway inflammatory responses to specific inhalation challenges (SICs) with low-molecular-weight (LMW) and high-molecular-weight (HMW) agents have not been studied thoroughly. We assessed the changes in airway inflammatory cells following SIC in sensitized workers, and looked at the influence of various factors on the pattern of inflammatory responses to SIC. Induced sputum analysis was performed in workers sensitized to LMW (n = 41) or HMW agents (n = 41) after a control day and after a positive SIC. Cell counts were compared with lung function and various clinical parameters. In the LMW group, eosinophils were increased following late asthmatic responses (median [interquartile range], 0.02 [0.04] × 10(6) cells/g vs 0.30 [0.80] × 10(6) cells/g and 1.0% [3.5] vs 8.9% [8.0], P < .05), as were neutrophil numbers (0.8 [1.3] × 10(6) cells/g vs 2.3 [5.4] × 10(6) cells/g, P = .04). In the HMW group, eosinophil percentages increased both after early (1.0% [2.2] vs 5.5% [14.5], P = .003) and dual asthmatic responses (4.5% [3.7] vs 15.0% [13.7], P = .02). In the LMW group, the increases in neutrophils were higher in current smokers than in ex-smokers or nonsmokers. The length of exposure to the agent, tobacco use, and baseline percentage of eosinophils were independent predictors of the change in eosinophils, whereas age and baseline neutrophil percentage were predictors of the change in neutrophils. This study confirms that eosinophils and neutrophils are increased after SIC, whatever the causal agent. The type of agent is not predictive of the inflammatory response to SIC. Smoking is associated with a more neutrophilic response after SIC with an LMW agent.

Bronchial Allergen Challenge in Allergic Children: Continuous Increase of Nitric Oxide in Exhaled Air 72 Hours After Allergen Inhalation Independent of Bronchial Obstruction

Changes in fractional exhaled nitric oxide (FeNO) occurring after bronchial allergen challenges (BAC) are still not understood, neither are any possible associations between FeNO and forced expiratory volume in 1 sec (FEV(1)). The aim of the study was to compare the fluctuations of FeNO and FEV(1), which occur within 72 h of BAC in children sensitive to grass pollen. Seventy-four children were divided into two groups based on their medical histories and the results of skin prick tests with 10 common allergens. Individuals in whom the test yielded a positive result to at least grass pollen (Group A, n = 57), and those with negative test results against all of the allergens applied (Group B, n = 17) were subjected to BAC. FeNO was measured at a baseline and at 1, 8, 21, and 72 h after the last dose of the allergen inhalation, whereas FEV(1) was measured at a baseline, hourly for 8 h after the challenge and at 21 and 72 h thereafter. Baseline FeNO in sensitive subjects (Group A) was significantly higher than in controls of Group B. In all grass pollen-sensitive subjects, even those that were free of a bronchial response, FeNO was markedly elevated compared to its baseline values, starting from the eighth hour onward, and still increased 72 h post-BAC, whereas FEV(1) returned to a baseline at the 72nd h post-BAC. The highest increase in FeNO was registered in individuals with a dual asthmatic response. An increase in FeNO in sensitive subjects starts a few hours later than the decrease in FEV(1). Consequently, measurements of FeNO seem to be useful in long-term monitoring of the allergic reaction triggered by a specific allergen.

P8 Unique outbreak of occupational asthma in toolmakers caused by chrome

IntroductionWe describe a unique outbreak of occupational asthma in toolmakers due to chrome. We investigated four employees of a medium-sized manufacturer of precision jet-engine parts for work-related asthma at our...

Functional genomics of the peripheral blood response to allergen inhalation challenge

Objective/purposeIn asthmatic individuals, airway narrowing representsthe early phase of the asthmatic response to allergeninhalation challenge, occurring within thirty minutes [1].In 50-60% of allergic asthmatic adults, the earlyresponse is followed by the late phase asthmaticresponse, usually starting between 3-4 hours after aller-gen inhalation challenge [2], and characterized mainlyby cellular inflammation of the airway [3]. The pathwaysleading to the late response are not completely under-stood. Understanding these pathways is important forevaluating allergic diseases such as asthma. In contrastto the more transient isolated early response, develop-ment of the late response is associated with the hall-mark inflammatory features of chronic allergic disease.MethodsNine adult subjects participating in ethically approvedallergen challenge studies were recruited followinginformed consent. Inclusion criteria included non-smo-kers with stable, mild to moderate atopic asthma, free ofother lung diseases. Subjects developing either an iso-lated early asthmatic response (≥20% drop in FEV1within 2 hours) or the dual asthmatic response (earlyresponse + ≥15% drop in FEV1 between 3-7 hours)were studied. Peripheral blood was drawn just prior toinhalation challenge and 2-3 hours post-challenge. Geneexpression analysis was performed using AffymetrixGeneChip® microarrays.Findings1783 genes were differentially expressed between pre-and post-inhalation challenge (p≤ 0.01). 364 genesremained significant at an FDR of 10%. Within this set,the DNAJC1 gene (p = 7.2e-5) has been previously iden-tified in a GWAS (genome-wide association study) asassociated with asthma. Gene ontology showed per-turbed activity in immune system process, mast cellsecretory granules and immunoglobulin biosynthesis.DeliverablesThe peripheral blood transcriptome was perturbedbetween pre-allergen inhalation challenge and 2-3 hourspost-challenge, with a focus on immunological func-tions. DNAJC1 was identified to be a gene for possiblefurther investigation. Additional recruitment of subjectsis underway to identify more specific biological path-ways that may be relevant to the onset of the late asth-matic response.RelevanceThis research will act as an initial step in identifyinggenes and pathways that may be involved in the moreclinically severe late asthmatic response that follows theearly response in more than half of the asthmatic popu-lation. The discovery of these biological pathways willallow for a better understanding of why some indivi-duals develop a dual response instead of an isolatedearly response. It will also indicate potential therapeutictargets that can be utilized to minimize the late asth-matic response, leading to better treatments for peoplewith asthma and other allergies.

Changes in serum proteins including antibodies and chemical mediators during the dual asthmatic response

Changes in serum proteins including antibodies and chemical mediators during the dual asthmatic response

Changes in Sputum Eicosanoids and Inflammatory Markers After Inhalation Challenges With Occupational Agents

An increase in cysteinyl-leukotrienes (LTs) after specific inhalation challenge (SIC) with common allergens in patients with atopic asthma has been shown previously, but there are scarce data with occupational agents. We sought to determine whether there are differences in lower airway inflammatory markers and the production of cytokines and eicosanoids between patients with a positive or negative SIC response to occupational agents. Twenty-six patients with suspected occupational asthma and 13 healthy control subjects were studied. Spirometry, methacholine challenge, and sputum induction were performed at baseline and 24 h after SIC with occupational agents. Several cytokines and inflammatory mediators, including eicosanoids, were measured in sputum. Twenty-six SICs were carried out with high-molecular-weight or low-molecular-weight agents, and the responses were positive in 18 patients. SIC elicited nine early asthmatic responses, two dual asthmatic responses, and seven isolated late asthmatic responses. Significant increments in sputum eosinophil counts were found only in patients with positive SIC responses compared with baseline values. Interleukin-10 levels were decreased in patients with positive and negative SIC responses compared to those in healthy control subjects. A significant increase (p < 0.05) in the LTC(4)/prostaglandin E(2) (PGE(2)) ratio was observed in patients after positive SIC responses compared to those with negative SIC responses. Overexpression of LTC(4), relative underproduction of PGE(2), and greater airway eosinophilia were observed in patients with positive SIC responses.

Platelet activation in allergic asthma patients during allergen challenge with Dermatophagoides pteronyssinus

Animal models of allergic asthma indicate that intravascular platelet activation is necessary for the development of allergen-induced chronic airway inflammation. To evaluate whether the development of a late asthmatic response (LAR) in allergic asthma patients challenged with a relevant allergen is consequent to platelet activation. Thirty-three house dust mite sensitive asthmatic patients were challenged intrabronchially with Dermatophagoides pteronyssinus (Dp) extract. Twelve non-atopic healthy subjects (HC) were used as controls. Platelet count and plasma levels of beta-thromboglobulin (beta-TG), platelet factor-4 (PF-4) and soluble P-selectin (sP-selectin) were assessed before the challenge (T(0)) and 30 min (T(EAR)), 6 h (T(LAR)) and 24 h (T(24)) after the challenge. Eleven patients responded to allergen challenge with an isolated early asthmatic response (single responders, SR). In 22 patients dual asthmatic response was demonstrated (dual responders, DR). At T(0) neither the platelet count nor the mean plasma level of beta-TG in DR or SR were different from HC, the mean plasma level of PF-4 in SR was significantly greater than in HC (P=0.01) or DR (P=0.001), the mean plasma level of sP-selectin was significantly greater in DR than in HC (0.0002) but not statistically different from SR (P=0.055). A significant decrease in the platelet count and increase in the plasma level of all the studied markers was seen at T(EAR), which was followed by a gradual return to the baseline values in the SR. Elevated plasma levels of platelet activation markers and decreased platelet count were seen in the DR even at T(24). Strong correlation was found between the increase in plasma concentration of beta-TG at T(EAR) and the maximum fall in forced expiratory volume in 1 s at T(LAR) (r=-0.57; P=0.0006). In allergic asthma patients development of prolonged airway inflammation after allergen challenge is associated with intravascular platelet activation.

The effect of Fel d 1‐derived T‐cell peptides on upper and lower airway outcome measurements in cat‐allergic subjects

We previously showed that overlapping Fel d 1-derived T-cell peptides inhibited surrogate markers of allergy (i.e. early and late-phase skin reactions and T-cell function) in cat allergic subjects. The present pilot study was designed to determine whether this treatment affected clinically relevant outcome measurements such as the allergen-induced nasal and bronchial reactions, and asthma/rhinitis quality of life (QOL). Sixteen cat-allergic asthmatic subjects who gave a dual (early and late) asthmatic response (DAR) to inhaled cat allergen were randomly assigned to receive either Fel d 1 peptides (approximately 300 mug in increasing, divided doses) or placebo (8 active : 8 placebo). Twelve single early responders (SER) were also studied in an open fashion design. Allergen-induced bronchial and nasal measurements as well as the QOL was measured at baseline, 4-8 weeks (follow-up 1 (FU1)) and 3-4 months (FU2). In the active, but not placebo, group there were significant decreases in the late asthmatic reaction (LAR) to whole cat dander (P = 0.03) at FU2 but with no between group difference. There were also significant improvements in asthma quality of life (QOL) scores [asthma-activity limitation (P = 0.014); rhinitis-sleep (P = 0.024), non-nose/non-eye symptoms (P = 0.031), nasal problems (P = 0.015)]. In the open study Fel d 1 peptide treatment resulted in significant decreases in number of sneezes (P = 0.05), weight of nasal secretions (P = 0.04) and nasal blockage (P = 0.01) following allergen challenge. Multiple, short, overlapping Fel d 1 T-cell peptides have potential for inhibiting upper and lower airway outcome measurements in cat allergic patients. Larger, dose-ranging, studies are required before firm conclusions on clinical efficacy of peptide allergen therapy can be made.

Effect of FK3657, a non-peptide bradykinin B 2 receptor antagonist, on allergic airway disease models

Bradykinin has been suggested to be involved in allergic diseases. In this study, we tested the effect of FK3657 (( E)-3-(6-acetamido-3-pyridyl)- N-[ N-[2,4-dichloro-3-[(2-methyl-8-quinolinyl)-oxymethyl]phenyl]- N-methylaminocarbonylmethyl]acrylamide), an orally active non-peptide bradykinin B 2 receptor antagonist, on allergic airway disease models in guinea pigs. FK3657 given orally inhibited bradykinin-induced or dextran sulfate (an activator of kinin–kallikrein cascade)-induced bronchoconstriction and plasma extravasation in the lower airways (trachea and main bronchi) and nasal mucosa of guinea pigs with ED 50 of 0.04–0.23 mg/kg. In the antigen-induced dual asthmatic response model of guinea pigs, FK3657 significantly attenuated the late phase asthmatic response, but not the immediate asthmatic response. FK3657 also significantly inhibited the 2,4-tolylene diisocyanate (TDI)-induced plasma extravasation in nasal mucosa of TDI-sensitized guinea pigs. These results suggest that oral FK3657 may be useful for asthma or allergic rhinitis as a therapeutic drug.

Glucoamylase: another fungal enzyme associated with baker's asthma

Aspergillus-derived enzymes are widely used as dough additives in the baking industry. These enzymes may give rise to immunoglobulin (Ig)E-mediated sensitization and occupational asthma. Glucoamylase (or amyloglucosidase) is an important industrial enzyme obtained from Aspergillus niger and used to provide fermentable sugars for yeast to improve loaf volume and texture. The aim of our study was to investigate the potential allergenic role of glucoamylase in baker's asthma. We report four subjects with work-related allergic respiratory symptoms who were exposed to glucoamylase and other starch-cleaving enzymes used as baking additives. The causative role of glucoamylase in work-related asthma was investigated by immunologic tests and specific inhalation challenges (SIC). Glucoamylase allergenic components were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. Skin prick tests to glucoamylase (10 mg/mL) gave a positive response in all patients. Further, a positive skin prick test to alpha-amylase was obtained in the four patients and to hemicellulase in two of them. SIC to glucoamylase elicited isolated early asthmatic responses in the three patients tested, and SIC to alpha-amylase elicited early asthmatic responses in two patients and a dual asthmatic response in another patient. Immunoblotting with glucoamylase showed several IgE-binding bands with molecular masses between 33 and 96 kD. IgE-inhibition assays showed scarce to moderate allergenic cross-reactivity between glucoamylase and alpha-amylase. These bakers had developed IgE-mediated occupational asthma to glucoamylase and alpha-amylase. Fungal glucoamylase is widely used as a baking additive and this enzyme may give rise to allergic respiratory reactions among exposed workers.

A comparative study on cockroach and ovalbumin sensitizations and challenge responses in Hartley guinea-pigs

The role of allergens in asthmatic inflammation is not clearly understood. To elucidate the mechanism of cockroach allergen (CRa)-induced airway disease, we studied three groups of Hartley guinea-pigs sensitized to control, ovalbumin (OA) or CRa. Parameters measured were anaphylactic antibodies by allergy skin test (AST), PCA assay and Western blot, changes in specific airway resistance (SRaw), analysis of bronchoalveolar lavage (BAL) and contracture responses of tracheal muscle (TSM) to non-specific and specific stimuli, in vitro. Both OA and CRa animals showed a similar allergic sensitization (AST and PCA), while Western blot identified several reaginic bands in CRa group compared to a single band in OA group. SRaw illustrated that CRa induce dual-asthmatic responses (4/6) in the CRa group, whereas OA induce only an early asthmatic response (3/6) in the OA group ( P<0.01). The average total leukocytes in BALF of the CRa were 27.0×10 6, mostly neutrophils and eosinophils, while those of the OA showed 3.5×10 6, mostly eosinophils, respectively ( P<0.0001). TSM responses to non-specific stimuli were similar in both groups ( P>0.1), while the antigen-specific TSM contractions were more brisk in the OA group than those of CRa group ( P<0.001). Thus, the study indicates that both CRa and OA sensitize guinea-pigs, yet CRa induces more severe and persistent late-phase inflammation than OA. This appears to be related to an influx of neutrophils rather than anaphylactic bronchospasm.