Methacholine Inhalation Challenge Research Articles

Mannitol vs. methacholine in the evaluation of airway responsiveness in bakers' asthma.

Various indirect or direct airway challenge tests are used to measure nonspecific bronchial hyper-responsiveness (NSBHR). The evaluation of NSBHR in diagnosing occupational asthma (OA) is performed, e.g., to monitor the specific inhalation challenge test (SICT). The aim of this study was to preliminarily compare the results of methacholine and mannitol inhalation challenge tests in SICT monitoring in bakers with work-related airway symptoms. Four bakery workers with a suspicion of OA underwent single-blind placebo-controlled SICTs involving workplace allergens, accompanied by the evaluation of NSBHR with mannitol and methacholine, both before and after SICTs. Clinical examinations, spirometry tests, skin prick tests (SPTs) to common aeroallergens and occupational allergens, as well as tests to determine serum specific IgE antibodies to occupational aeroallergens were also performed. Positive SPTs results to occupational aeroallergens were found in all bakery workers, and specific IgE antibodies to flour were detected in 2 subjects. Three patients displayed positive SICT reactions. In all of these 3 patients, airway responsiveness to methacholine increased significantly. In 2 patients, airway reaction to mannitol was significant, whereas in 1 subject there was no increase in NSBHR after mannitol inhalation. The patient with a negative SICT result did not reveal any changes in NSBHR before and after the test, either to methacholine or mannitol. The data obtained by the authors show that there is no clear correlation between the methacholine and mannitol inhalation challenge tests in SICT monitoring. Preliminary results indicate the need for further investigations to evaluate the usefulness of the mannitol challenge test in the diagnostics of OA. Int J Occup Med Environ Health. 2020;33(2):235-9.

Asthma and rhinitis in Greek furniture workers

Objective: The detection of asthma and rhinitis in furniture workers exposed to chemicals in the area of Thessaloniki Greece and the determination of the most useful tests for diagnosing the above occupational diseases.Methods: Eighty-three workers (76 men), 35 exposed to chemicals (CW), 23 to wood dust (WW), and 25 office workers (OW), serving as controls, filled in a specialized European Community Respiratory Health Survey (ECRHS) questionnaire for asthma and were submitted to clinical evaluation, spirometry, bronchodilation test, PEF computer algorithm OASYS-2, FeNO, skin prick tests (SPTs), rhinomanometry and methacholine inhalation challenge. Working conditions and protective measurements were also recorded. According to the results of all conducted tests, each subject was distributed to a subgroup: (a) normal, (b) asthma, (c) rhinitis, (d) asthma and rhinitis. Comparisons were performed among work groups.Results: The presence of asthma and/or rhinitis was higher among CW and WW compared to OW (p = 0.004). Significant differences among groups were observed in the questions «better weekend» (p < 0.034) and “improvement on vacation» (p < 0.000), in OASYS-2 Score (p < 0.000), in ABC Score (p < 0.000), and in methacholine score (p < 0.022). Rhinomanometry, FeNO, spirometry, and spirometry after bronchodilation had no significant differences among groups. Working conditions, ventilation system, work practice, use and type of mask revealed no significant differences.Conclusion: Asthma and rhinitis are significantly common among CW. Protective measurements used were not adequate to prevent asthma and or work related rhinitis. Early diagnosis might contribute to disease prevention and control.

Variation at DENND1B and Asthma on the Island of Tristan da Cunha.

A high prevalence of asthma has been documented among the inhabitants of Tristan da Cunha, an isolated island in the South Atlantic. The population derives from just 28 founders. We performed lung function testing, including methacholine inhalation challenge, allergen skin prick testing, and collected DNA from essentially all of the current island population (269 individuals), and genotyped a panel of 43 single-nucleotide polymorphisms (SNPs) reported as associated with asthma and atopy. We carried out a mixed-model association analysis using the known pedigree. There were 96 individuals diagnosed as asthmatic (36%), and heritability estimates were similar to those from nonisolated population samples (multifactorial threshold model, h2 = 48%). The first component from a genetic principal components analysis using the entire SNP panel was nonlinearly associated with asthma, with the maximum risk to those intermediate to reference (Human Genome Diversity Project) European and African samples means. The single most strongly associated SNP was rs2786098 (p = 5.5 × 10-5), known to regulate the gene DENND1B. This explained approximately one-third of the trait heritability, with an allelic odds ratio for the A allele of 2.6. Among A/A carriers, 10 out of 12 individuals were asthmatic. The rs2786098*A variant was initially reported to decrease the risk of childhood (atopic) asthma in European but slightly increase the risk in African-descended populations, and does significantly alter Th2 cell function. Despite an absence of overall association with this variant in recent asthma genome wide association studies meta-analyses, an effect may exist on the particular genetic background of the Tristan da Cunha population.

Methacholine challenge testing: comparative pharmacology.

Standardization of the methacholine inhalation challenge, the most common direct bronchoprovocation test, is important. One aspect of standardization is the appropriate washout period for pharmacologic agents which affect the response. This review summarizes the available data on pharmacologic inhibition of the methacholine response. Specific (anti-muscarinic) agents demonstrate marked bronchoprotection (up to 7 days for the long-acting drugs) which lasts longer than the duration of bronchodilation. The functional antagonist (beta 2 agonist class of medications) shows marked, but less, bronchoprotection which is relatively short lived and is similar to the duration of bronchodilator efficacy. Tolerance develops quickly, especially to the long-acting agents. Single doses of controller medications, such as inhaled corticosteroids (ICS) and leukotriene receptor antagonists, have no effect on the methacholine test, while regular use, at least for ICS, has a modest protective effect whose duration is uncertain and likely variable. Theophylline has a small effect and H1 blockers (all generations) have a negligible effect.

The KAAACI Standardization Committee Report on the procedure and application of the bronchial provocation tests

Bronchial provocation tests are of value in the evaluation of airway hyperresponsiveness. Nonspecific bronchial challenge (metha choline, mannitol, exercise, etc.) is used when the symptoms, physical examination, and measurements of pulmonary function are unremarkable in the diagnosis of asthma, when a patient is suspected of having occupational asthma or exercise-induced broncho constriction (EIB), and when a screening test for asthma or EIB is required for some occupational groups in whom bronchospasm would pose an unacceptable hazard. Methacholine inhalation challenge is most widely used pharmacologic challenge and highly sensitive. For appropriate interpretation of the results of methacholine provocation, it is important to perform the test with the stan dardized protocol and to recognize that inhalation methods significantly influence the sensitivity of the procedure. Indirect chal lenges (e.g., mannitol and exercise) correlate with airway inflammation and are more specific but less sensitive for asthma. Indirect provocation tests are used to confirm asthma, to differentiate asthma from other airway diseases, and to evaluate EIB. (Allergy Asthma Respir Dis 2018;6:14-25)

Changes in the breath sound spectrum during methacholine inhalation in children with asthma.

An effort-independent breath sound analysis is expected to be a safe and simple method for clinical assessment of changes in airway function. The effects of bronchoconstriction and bronchodilation on novel breath sound parameters in asthmatic children were investigated. The study population included 49 children with atopic asthma (male = 33; mean age: 10.2 years). We evaluated breath sound parameters of the highest frequency of the power spectrum (HFp), frequency limiting 50% and 99% of the power spectrum (F50 and F99 ) and roll-off from 600 Hz to the HFp (Slope). We also assessed new parameters obtained using the ratios of sound spectrum parameters (spectrum curve indices), such as the ratio of the third and fourth power area to the total power area (P3 /PT and P4 /PT ), the ratio of the third and fourth areas to the total area under the curve (A3 /AT and B4 /AT ) and the ratio of power and frequency at 75% of HFp and 50% of HFp (RPF75 and RPF50 ). This was measured before and after methacholine inhalation challenge and after β2 agonist inhalation. The parameters, F50 and F99 , showed no changes after methacholine inhalation. Conversely, the A3 /AT (12.5-10.0%, P < 0.001), B4 /AT (7.6-5.5%, P < 0.001), RPF75 (6.7-4.0 dBm/Hz, P < 0.001) and RPF50 (5.8-4.3 dBm/Hz, P < 0.001) were significantly decreased. These values returned to the original level after β2 agonist inhalation. Spectrum curve indices indicate bronchoconstriction and bronchodilation. These parameters may play a role in the assessment of airway narrowing in asthmatic children.

ASTHMA-OBESITY NEUTROPHILIC INFLAMMATION AS A DISTINCT PHENOTYPE

Background & objectives: Asthma in obese subjects has been suggested to differ from classical phenotypes of asthma. Obesity is associated with activation of innate immune response in which neutrophilic activation is a fundamental process. However, airway inflammation in obese asthmatics is not well characterized, but may involve neutrophils. The present work was designed to study the possible airway and systemic neutrophilic inflammation as a distinct feature of asthma in obese asthma phenotype. Methods: Study included 30 obese asthmatics (BMI ≥ 30 kg/m2), 8 non-obese asthmatics (BMI< 25 kg/m2) and 7 normal non-obese subjects (BMI< 25 kg/m2). Anthropometric measurements and pulmonary flow rates were assessed for all subjects. Methacholine inhalation challenge was performed only in asthmatics. Blood and sputum samples were tested for neutrophilic and eosinophilic counts, as well as levels of interleukin-8 (IL-8)and myeloperoxidase (MPO) enzyme, as markers of neutrophilic activity.Results: There was no significant difference between obese and non-obese asthmatics as regard the mean value of the provocative dose of methacholine (PD20-FEV1). Compared to non-obese asthmatics, obese asthmatics demonstrated significantly higher blood and sputum neutrophilic counts and significantly lower blood and sputum eosinophilic counts. However, on comparing IL-8 and MPO levels between the obese asthmatic group and non-obese asthmatic group, there were insignificant trends toward increased serum and sputum levels of IL-8 and serum level of MPO in the obese asthmatic group. In asthmatic subjects, there was a significant positive correlation between BMI and serum MPO levels. Conversely, BMI showed significant negative correlations with both sputum eosinophilic count and blood absolute eosinophilic count. Conclusions: Findings suggest that neutrophil predominant airway inflammation is more likely to be a distinct inflammatory phenotype of asthma in obese asthmatic subjects, though further studies are needed to detect significant effects of obesity on markers of neutrophil activity in asthmatic subjects to shed more light on the possible role of neutrophilic inflammation in the association between obesity and asthma. Keywords: Obesity, Bronchial asthma, Asthma phenotypes.

The impact of food allergens on airway responsiveness in schoolchildren with asthma: A DBPCFC study.

Despite the growing evidence of a possible link between asthma and food allergy (FA), so far, the involvement of food in inducing respiratory symptoms has not been fully evaluated. The objective of this study was to evaluate the impact of food allergens on respiratory symptoms and bronchial reactivity (BHR) in schoolchildren with asthma. The initial study group consisted of 362 children with asthma. In the end, 22 children with concomitant FA, and 18 without FA, were selected to participate in the study. Spirometry and Methacholine Inhalation Challenge (MIC) were conducted prior to and after the completion of a double blind placebo control food challenge (DBPCFC). The food-induced asthmatic reactions were observed in nine (2.5%) out of all 362 children with asthma. Mean FEV1 prior to and after allergen or placebo challenge did not differ between the groups studied. Increase of BHR after DBPCFC was seen in 17 (4.7%) children with asthma. The mean PC20 value in children with FA was 1.41 ± 1.12 mg/ml prior to the allergen challenge and 0.86 ± 0.71 mg/ml (P = 0.002) after the test, whereas these values were 1.93 ± 1.68 mg/ml and 2.02 ± 1.75 mg/ml, respectively, in children without FA (P > 0.05). Significant differences were noted after the allergen provocation in children with FA as compared to children without FA (P = 0.007). Although food allergens are a rare trigger of food-induced asthmatic reactions in schoolchildren with asthma, they could enhance BHR, despite a lack of evident clinical respiratory signs and decreased in FEV1 values after food challenge. Pediatr Pulmonol. 2016;51:787-795. © 2016 Wiley Periodicals, Inc.

Occupational allergic multiorgan disease induced by wheat flour

Bakers are repeatedly exposed to wheat flour (WF) and may develop sensitization and occupational rhinoconjunctivitis and/or asthma to WF allergens.1 Several wheat proteins have been identified as causative allergens of occupational respiratory allergy in bakery workers.1 Testing of IgE reactivity in patients with different clinical profiles of wheat allergy (food allergy, wheat-dependent exercise-induced anaphylaxis, and baker's asthma) to salt-soluble and salt-insoluble protein fractions from WF revealed a high degree of heterogeneity in the recognized allergens. However, mainly salt-soluble proteins (albumins, globulins) seem to be associated with baker's asthma, and prolamins (gliadins, glutenins) with wheat-dependent exercise-induced anaphylaxis, whereas both protein fractions reacted to IgE from food-allergic patients.1 Notwithstanding, gliadins have also been incriminated as causative allergens in baker's asthma.2 We report on a 31-year-old woman who had been exposed to WF practically since birth because her family owned a bakery housed in the same home where they lived. She moved from this house when she was 25 years, but she continued working every day in the family bakery. In the last 8 years she had suffered from work-related nasal and ocular symptoms such as itching, watery eyes, sneezing, nasal stuffiness, and rhinorrhea. These symptoms markedly improved when away from work and worsened at work. In the last 5 years, she had also experienced dysphagia with frequent choking, especially when ingesting meats or cephalopods, which had partially improved with omeprazole therapy. Two years before referral to our clinic, she began to have dry cough and breathlessness, which she also attributed to her work environment. Upper and lower respiratory tract symptoms increased when sifting the WF and making the dough. The patient did not experience gastrointestinal symptoms with ingestion of cereal products. Skin prick test results were positive to grass (mean wheal, 6 mm), cypress (5 mm) and Russian thistle pollen (4 mm), WF (4 mm), and peach lipid transfer protein (6 mm) and were negative to rice flour, corn flour, profilin, mites, molds, and animal dander. Skin prick test with a homemade WF extract (10% wt/vol) was strongly positive (15 mm). Serologic tests yielded the following results: eosinophil cationic protein, 47 ?g/L; total serum IgE, 74 kU/L; specific IgE (ImmunoCAP; ThermoFisher, Uppsala, Sweden) to WF, 7.4 kU/L; barley flour, 1.24 kU/L; and corn, gluten, alpha-amylase, peach, and apple, less than 0.35 kU/L. Specific IgE binding to microarrayed purified WF allergens (WDAI-0.19, WDAI-0.53, WTAI-CM1, WTAI-CM2, WTAI-CM3, WTAI-CM16, WTAI-CM17, Tri a 14, profilin, ?-5-gliadin, Tri a Bd 36 and Tri a TLP, and gliadin and glutamine fractions) was assessed as described elsewhere.3 The patient's serum specifically recognized ?-5-gliadin and the gliadin fraction, and no IgE reactivity was observed to other wheat allergens. Spirometry revealed a forced vital capacity of 3.88 L (88%), an FEV1 of 3.04 L (87%), and FEV1/forced vital capacity of 83%. A methacholine inhalation test was performed following an abbreviated protocol,4 and the results were expressed as PD20 in cumulative dose (mg) of methacholine. Methacholine inhalation challenge test result was positive (0.24 mg cumulative dose) when she was working, and after a 3-month period away from work and with no visits to the bakery house, it gave a negative result. A chest x-ray was normal. Specific inhalation challenge test was carried out in the hospital laboratory by tipping WF from one tray to another for 15 minutes. Spirometry was performed at baseline and at 2, 5, 10, 15, 20, 30, 45, and 60 minutes after the challenge with WF. Peak expiratory flow was measured at baseline and then hourly over 24 hours (respecting sleeping time). A 12% fall in FEV1 was observed at 20 minutes and a 26% drop in peak expiratory flow at 9 hours after exposure to WF,

Leukotriene D4inhalation challenge for predicting short-term efficacy of montelukast: a pilot study

The convenient measure to predict efficacy of leukotriene receptor antagonist is lacking. To determine if leukotriene D4 inhalation challenge predicts short-term efficacy of montelukast in asthma. In this open-labelled 28-day trial, 45 patients with asthma were allocated to leukotriene-sensitive and leukotriene-insensitive group to receive montelukast monotherapy (10 mg, once daily) based on the positive threshold of leukotriene D4 inhalation challenge test (4.800 nmol). Miscellaneous measurements comprised fractional exhaled nitric oxide, methacholine inhalation challenge, Asthma Control Test and Asthma Quality of Life Questionnaire. Peak expiratory flow was self-monitored throughout the treatment. End point assessments were performed 3 to 5 days after montelukast withdrawal. Twenty-three patients in leukotriene-sensitive group and 10 leukotriene-insensitive group completed the study. Both groups differed neither in 28-day peak expiratory flow rate nor in maximal weekly peak expiratory flow (both P > 0.05). However, minimal weekly peak expiratory flow was significantly higher in leukotriene-insensitive group throughout the treatment course (all P < 0.05) except for week 1 (P > 0.05). Both groups did not differ statistically in the post-treatment improvement in forced expiratory volume in 1 s (FEV1 ) predicted% prior to inhalation challenge, fractional exhaled nitric oxide or the airway responsiveness to leukotriene D4 or methacholine (all P > 0.05). There was a marked increase in Asthma Control Test score and the symptom score of Asthma Quality of Life Questionnaire in both groups (both P < 0.05). The overall significance of Logistic regression model was unremarkable (P = 0.467). Responsiveness to inhaled leukotriene D4 alone might not be sufficient to predict the short-term efficacy of montelukast monotherapy in patients with asthma.

Evaluation of Pulmonary and Systemic Toxicity of Oil Dispersant (COREXIT EC9500A(®)) Following Acute Repeated Inhalation Exposure.

INTRODUCTIONOil spill cleanup workers come into contact with numerous potentially hazardous chemicals derived from the oil spills, as well as chemicals applied for mitigation of the spill, including oil dispersants. In response to the Deepwater Horizon Macondo well oil spill in the Gulf of Mexico in 2010, a record volume of the oil dispersant, COREXIT EC9500A, was delivered via aerial applications, raising concern regarding potential health effects that may result from pulmonary exposure to the dispersant.METHODSThe current study examined the effects on pulmonary functions, cardiovascular functions, and systemic immune responses in rats to acute repeated inhalation exposure of COREXIT EC9500A at 25 mg/m3, five hours per day, over nine work days, or filtered air (control). At one and seven days following the last exposure, a battery of parameters was measured to evaluate lung function, injury, and inflammation; cardiovascular function; peripheral vascular responses; and systemic immune responses.RESULTSNo significant alterations in airway reactivity were observed at one or seven days after exposure either in baseline values or following methacholine (MCh) inhalation challenge. Although there was a trend for an increase in lung neutrophils and phagocyte oxidant production at one-day post exposure, there were no significant differences in parameters of lung inflammation. In addition, increased blood monocytes and neutrophils, and decreased lymphocyte numbers at one-day post exposure also did not differ significantly from air controls, and no alterations in splenocyte populations, or serum or spleen immunoglobulin M (IgM) to antigen were observed. There were no significant differences in peripheral vascular responsiveness to vasoconstrictor and vasodilator agonists or in blood pressure (BP) responses to these agents; however, the baseline heart rate (HR) and HR responses to isoproterenol (ISO) were significantly elevated at one-day post exposure, with resolution by day 7.CONCLUSIONSIn summary, acute repeated exposure to COREXIT EC9500A did not alter pulmonary function, lung injury/inflammation, systemic immune responses, or vascular tone, but did cause transient chronotropic effects on cardiac function.

The adult with chronic cough and cat allergy

Case report A 31-year old man, tenor, present with a history of chronic cough of two years duration. The cough was present day and night, much more during singing, with little mucus production and some associated feeling of shortness of breath and choking sensation, especially at night. Additional complaints included postnasal drip, runny nose, sensation of mucus in the throat and symptoms of heartburn and acid indigestion. The patient was referred in our clinic, after inadequate response to previous treatments prescribed by previous specialists, including antihistamines, nasal steroid sprays, oral prednisone, antibiotics, combine therapy and proton-pump inhibitors. Physical examination was unremarkable. Spirometric values were normal. Results of chest radiography, computed tomographic scans of the sinuses, and high-resolution computed tomographic scans of the chest were all normal. The patient underwent a methacholine inhalation challenge. FEV1 was reduced 7% at the highest concentration (25 mg/ml). Bronchoscopy was normal . The esophageal pH monitoring was resulted positive. Skin prick test and RASTs resulted positive for cat dander. As the methacoline test was negative, patient was challenged in Italy, with a well-characterized cat-exposure model. Challenge result was considered positive for the upper respiratory symptoms, but there was no significant decline in FEV1 at 6 or 23 hours after cat exposure, the maximum fall was 9%. The patient was treated with cat-immunotherapy 15 μg of Fel d 1 at maintenance dose, and conservative therapy with combine therapy for 1 year, with no clinical improvement. He performed surgical intervention of the Nissen fundoplication, laparoscopically. There was significant improvement in quality of life only at 3 months after surgery. Because the patient’s symptoms did not improve, we advised him to continue catimmunotherapy, nasal steroid sprays, treatment with combine therapy and to stay away from the work and home environment for a period of time. Some months later the symptoms were significantly improved. Cat and dog allergens are commonly present in homes without pets, as well as in a variety of public buildings, and these are carried from one home to another on the clothing of pet owners. Non-cat owners can collect cat allergen on their clothing, most likely by both airborne and direct contact. Repeated low-level allergen exposure may induce chronic airway changes, specifically increases in airway hyperresponsiveness.

Relationship between bronchial hyperresponsiveness and lung function in children age 5 and 6 with and without asthma

It is unknown whether wheezy children have bronchial hyperresponsiveness (BHR) or which lung function parameters are correlated with BHR in children. We evaluated the relationship between BHR parameters and the lung functions by minimizing the effects of age and height in asthmatic, non-asthmatic wheezers and healthy children. The subjects comprised of 154 children aged 5 and 6 years (78 males, 76 females), who were divided into three groups: asthmatics, non-asthmatic wheezers and healthy controls. Spirometry and a methacholine inhalation challenge by the oscillation method were performed. The age of the study cohort was 5.9 ± 0.2 years (mean ± standard deviation), and the height was 114.4 ± 5.3 cm. No significant differences in height, weight, body mass index or lung function were observed in the three groups. The minimal dose of methacholine to start bronchoconstriction, a parameter of bronchial sensitivity, was lower in asthmatics and non-asthmatic wheezers than that in controls. The speed of bronchoconstriction in response to methacholine, a parameter of bronchial reactivity, was strongly correlated with baseline respiratory resistance (Rrs cont) in all three groups. Our data suggest that it not possible to distinguish preschool children with asthma from non-asthmatic wheezers based on their bronchial sensitivity and that the baseline Rrs has a strong effect on the bronchial reactivity in children.

Comparison of the effects of esomeprazole and fundoplication on airway responsiveness in patients with gastro‐oesophageal reflux disease

Gastro-oesophageal reflux disease (GORD) is suggested to cause or aggravate several respiratory conditions. Studies with proton pump inhibitors have resulted in only minor improvements in pulmonary outcomes in patients with GORD. It has been speculated that operative treatment of GORD might be more efficient as it also diminishes non-acidic reflux. To compare the effects of esomeprazole 40 mg bid and fundoplication on airway responsiveness, forced expiratory volume in 1 s (FEV1), exhaled nitric oxide (NO) and respiratory symptoms in patients with moderate-to-severe GORD. Sixty-nine GORD patients had methacholine inhalation challenge performed on them, and FEV1, exhaled NO and respiratory symptoms were measured at baseline, after a 3-month treatment with esomeprazole and 3 months after fundoplication. Primary outcome variable was dose-response slope (DRS), i.e. decline in FEV1 during methacholine challenge divided with the amount of methacholine administered (%/μmol). Pre-defined subgroup analysis was performed among those with concomitant asthma (n = 12). There was no improvement in DRS, FEV1 or exhaled NO after esomeprazole treatment or fundoplication. Cough and dyspnoea measured with visual analog scale improved with esomeprazole treatment (P < 0.001), and further after fundoplication (P < 0.001). Among those with concomitant asthma, significant improvements in St George Respiratory Questionnaire (SGRQ) scores could be seen after fundoplication. Neither esomeprazole treatment nor fundoplication diminishes airway responsiveness or exhaled NO, or improves FEV1 in patients with GORD. Improvements in respiratory symptoms and SGRQ scores after GORD treatments could be detected. However, as this was not a placebo-controlled study, the findings in these secondary endpoints should not be emphasised. ClinicalTrials.cov: NCT00994708.

Transcriptional Changes of Blood Eosinophils After Methacholine Inhalation Challenge in Asthmatics.

BackgroundMethacholine challenge is commonly used within the asthma diagnostic algorithm. Methacholine challenge has recently been shown to induce airway remodelling in asthma via bronchoconstriction, without additional airway inflammation. We evaluated the effect of methacholine-induced bronchoconstriction on the peripheral whole-blood transcriptome.MethodsFourteen males with adult-onset, occupational asthma, 26–77 years of age, underwent methacholine inhalation challenges. The concentration of methacholine eliciting a ≥20% fall in FEV1 (PC20) was determined. Blood was collected immediately prior to and two hours after challenge. Complete blood counts and leukocyte differentials were obtained. Transcriptome analysis was performed using Affymetrix GeneChip® Human Gene 1.0 ST arrays. Data were analyzed using robust LIMMA and SAM. The cell-specific Significance Analysis of Microarrays (csSAM) algorithm was used to deconvolute the gene expression data according to cell type.ResultsMicroarray pathway analysis indicated that inflammatory processes were differentially affected. CsSAM identified 1,559 transcripts differentially expressed (all down-regulated) between pre- and post-methacholine in eosinophils at a false discovery cutoff of 10%. Notable changes included the GOLGA5 and METTL2B genes and the protein ubiquitination and CCR3 pathways.ConclusionsWe demonstrated significant changes in the peripheral blood eosinophil-specific transcriptome of asthmatics two hours after methacholine challenge. CCR3 and protein ubiquitination pathways are both significantly down-regulated.

Interleukin-18 and interleukin-18 receptor- expression in allergic asthma

To the Editors: The inflammatory process in allergic asthma is initiated by T-helper (Th) type-2 cells, which produce a repertoire of cytokines, including interleukin (IL)-4, IL-5, IL-9 and IL-13, which are necessary for immunoglobulin (Ig)E production, airway eosinophilia and goblet cell hyperplasia [1]. IL-18 is another pro-inflammatory cytokine, initially described as interferon (IFN)-γ-inducing factor [2]. IL-18 can act as a cofactor for Th2 cell development and IgE production [3]. Recently, an IL-18 gene polymorphism was reported to be associated with asthma severity and higher serum IL-18 levels: the rs5744247 variant, which has higher transcriptional activity than the wildtype allele [4]. In addition, the IL-18 receptor (IL-18R) gene (on 2q21) has been identified as a candidate gene associated with increased susceptibility to asthma in children [5], and polymorphisms of the gene have been associated with allergic asthma and airway hyperresponsiveness (AHR) [6]. We have evaluated serum levels of IL-18 and the expression of IL-18Rα, as well as other Th2-associated cytokines, in stable allergic asthmatic subjects, compared with allergic nonasthmatic subjects and healthy controls. We studied 36 subjects, which included 15 allergic asthmatic subjects, 11 nonasthmatic allergic subjects and 10 healthy controls (table 1). All subjects underwent a methacholine inhalation challenge [7] and had skin-prick tests to a panel of 16 environmental allergens. Total IgE, and serum IL-18, IL-4, IL-10, IL-12, IL-13 and IFN-γ were measured using commercially available ELISA kits (Medical and Biological Laboratories Co., Nagoya, Japan; RD DRG International Inc., Mountainside, NJ, USA). The allergic subjects were studied outside …

Comparison of alveolar nitric oxide concentrations using two different methods for assessing small airways obstruction in asthma

Fractional exhaled nitric oxide (F(E) NO) is considered a potentially useful biomarker for airway inflammation. A two-compartment model (2CM) of pulmonary NO dynamics has been used for the evaluation of bronchial NO flux (J'awNO) and alveolar NO concentration (C(A) NO) in asthmatic patients. Recently, the trumpet shape of the airway tree and axial diffusion (TMAD) model has been reported as a modification of the 2CM. This study was designed to determine the validity of C(A) NO measurement using the TMAD model for assessing small airways inflammation in asthma. A total of 52 asthmatic patients and 12 normal control subjects were included in the study. Methacholine inhalation challenge and pulmonary function tests, sputum induction, and exhaled NO measurements at several flow rates were performed. J'awNO and C(A) NO were calculated using both the 2CM (C(A) NO( 2CM) , J'awNO( 2CM) ) and TMAD models (C(A) NO( TMAD) , J'awNO( TMAD) ). Both J'awNO (J'awNO( 2CM) and J'awNO( TMAD) ) and C(A) NO (C(A) NO( 2CM) and C(A) NO( TMAD) ) were significantly higher in asthmatic patients than in control subjects. C(A) NO( 2CM) was significantly correlated with FEV(1) /FVC (r = -0.35, P = 0.01), FEF(25-75) (r = -0.45, P < 0.001) and sputum eosinophils (r = 0.32, P = 0.02). In contrast, C(A) NO( TMAD) was significantly correlated with FEF(25-75) (r = -0.42, P = 0.002) but not with FEV(1) /FVC or sputum eosinophils. C(A) NO( TMAD) is more specific as an indicator of small airways obstruction than C(A) NO( 2CM) . Assessment of small airways obstruction using the TMAD model may clarify the role of the small airways in the pathogenesis of asthma.

Association of serum-soluble CD26 and CD30 levels with asthma, lung function and bronchial hyper-responsiveness at school age

There is a need for markers of Th1 and Th2 imbalance in diseases such as asthma. CD30 is an activation marker of Th2 cells, and importance of Th1 marker CD26 was recently found in adult asthma. We studied whether serum-soluble CD30 (sCD30) or serum-soluble CD26 (sCD26) could support early diagnosis of asthma in children at school age. sCD26 and sCD30 were measured in 34 children with clinically confirmed asthma, 31 with possible asthma and in 147 controls. In addition, the associations of flow volume spirometry, methacholine inhalation challenge and free running test results with serum sCD26 or sCD30 were analysed. Serum sCD30 was significantly higher in children with confirmed asthma (mean 91.5 IU/mL, SD 23.0) than in the controls (78.8 IU/mL, 25.9; p = 0.042). No significant differences were found in serum sCD26 levels between the groups. There was a negative correlation of mean mid expiratory flow values with serum sCD26 (r = -0.22, p = 0.0018). Neither methacholine inhalation challenge nor free running test results were associated with serum sCD26 or sCD30. Serum sCD30 was higher in children with asthma. However, marked overlap in serum sCD30 between asthmatic and healthy children limits the usefulness of sCD30 as a diagnostic marker of asthma.

SQ-standardized house dust mite immunotherapy as an immunomodulatory treatment in patients with asthma.

BackgroundSpecific immunotherapy is the only treatment with the potential to prevent progression of the allergic disease and the potential to cure patients. The immunomodulatory ability of SQ-standardized house dust mite (HDM) subcutaneous immunotherapy (SCIT) was investigated in patients with allergic asthma.MethodsFifty-four adults with HDM-allergic asthma were randomized 1 : 1 to receive SQ-standardized HDM SCIT (ALK) or placebo for 3 years. At baseline, and after 1, 2 and 3 years of treatment, the lowest possible inhaled corticosteroid dose required to maintain asthma control was determined, followed by determinations of nonspecific and HDM-allergen-specific bronchial hyperresponsiveness, late asthmatic reaction (LAR), immediate and late-phase skin reactions, and immunological response.ResultsSQ-standardized HDM SCIT provided a statistically significantly higher HDM-allergen tolerance (P < 0.05 vs placebo) in terms of a 1.6-fold increase in PD20 (HDM-allergen inhalation challenge), a 60-fold increase in skin test histamine equivalent HDM-allergen concentrations, reduced immediate- and reduced or abolished late-phase skin reactions, as well as fewer patients with LAR. PD20 (methacholine inhalation challenge) increased initially and was similar between groups. House dust mite SCIT induced an initial increase in serum HDM-allergen-specific IgE (P = 0.028 vs placebo), which then declined to baseline value. House dust mite SCIT induced an increase in components blocking IgE binding to allergen [ΔIgE-blocking factor: 0.31; 95% CI of (0.26; 0.37)] after 1 year that remained constant after 2 and 3 years (P < 0.0001 vs placebo).ConclusionSQ-standardized HDM SCIT induced a consistent immunomodulatory effect in adults with HDM-allergic asthma; the humoral immune response was changed and the HDM-allergen tolerance in lung and skin increased.

Changes in the highest frequency of breath sounds without wheezing during methacholine inhalation challenge in children

It is difficult for clinicians to identify changes in breath sounds caused by bronchoconstriction when wheezing is not audible. A breath sound analyser can identify changes in the frequency of breath sounds caused by bronchoconstriction. The present study aimed to identify the changes in the frequency of breath sounds during bronchoconstriction and bronchodilatation using a breath sound analyser. Thirty-six children (8.2 +/- 3.7 years; males : females, 22 : 14) underwent spirometry, methacholine inhalation challenge and breath sound analysis. Methacholine inhalation challenge was performed and baseline respiratory resistance, minimum dose of methacholine (bronchial sensitivity) and speed of bronchoconstriction in response to methacholine (Sm: bronchial reactivity) were calculated. The highest frequency of inspiratory breath sounds (HFI), the highest frequency of expiratory breath sounds (HFE) and the percentage change in HFI and HFE were determined. The HFI and HFE were compared before methacholine inhalation (pre-HFI and pre-HFE), when respiratory resistance reached double the baseline value (max HFI and max HFE), and after bronchodilator inhalation (post-HFI and post-HFE). Breath sounds increased during methacholine-induced bronchoconstriction. Max HFI was significantly greater than pre-HFI (P < 0.001), and decreased to the basal level after bronchodilator inhalation. Post-HFI was significantly lower than max HFI (P < 0.001). HFI and HFE were also significantly changed (P < 0.001). The percentage change in HFI showed a significant correlation with the speed of bronchoconstriction in response to methacholine (P = 0.007). Methacholine-induced bronchoconstriction significantly increased HFI, and the increase in HFI was correlated with bronchial reactivity.