ABSTRACT
BACKGROUND: Bronchial hyperresponsiveness is usually measured by bronchial challenge test with direct (e.g., methacholine) and indirect (e.g., adenosine) agonists. There are few studies comparing both types of agents and they have had conflicting concordance. OBJECTIVE: We sought to compare the results of both tests in a population with symptoms suggestive of asthma so as to determine their relationship with bronchial inflammatory markers. METHODS: Seventy-nine patients whose age ranged from 14 to 81 years were recruited for this study. Challenge tests were performed using the tidal volume method. PC20 methacholine and PC15 and PC20 adenosine were calculated. Induced sputum and fraction of exhaled nitric oxide measurements were also performed. RESULTS: Atopy was found in 69% of the patients. Methacholine PC20 and adenosine PC15 were positive in 32 patients (40.5%), both having a sensitivity of 73%. Percentage of agreement was 45.45% and κ index was only 0.369. Adenosine PC20 elicited lower sensitivity and agreement. No correlation between methacholine PC20 and adenosine PC15 was observed. Higher fraction of exhaled nitric oxide values and sputum eosinophil counts were seen in patients with positive adenosine challenge results. The use of adenosine PC15 or PC20 did not alter the association with inflammatory markers. CONCLUSIONS: The concordance between both techniques was low. Methacholine is not a reliable predictor of hyperresponsiveness to adenosine, leading us to conclude that the two tests are complementary but not interchangeable in clinical practice. Additionally, responsiveness to the two bronchoconstrictor stimuli does not indicate presence of the same airway abnormality. Indirect stimuli provide a better reflection of bronchial inflammation.
Subject(s)
Adenosine , Asthma/diagnosis , Biomarkers/analysis , Bronchial Hyperreactivity/diagnosis , Bronchoconstrictor Agents , Methacholine Chloride , Adolescent , Adult , Aged , Aged, 80 and over , Breath Tests , Bronchi/physiopathology , Bronchial Hyperreactivity/physiopathology , Eosinophils/cytology , Exhalation , Female , Humans , Inflammation/diagnosis , Leukocyte Count , Male , Middle Aged , Nitric Oxide , Sensitivity and Specificity , Sputum/cytology , Young AdultABSTRACT
BACKGROUND: Symptoms of obstructive lung disease in domestic cleaning staff have been related to the use of bleach and other irritant cleaning products. MATERIAL AND METHODS: Included in the study were thirteen cleaning employees with work-related asthma-like symptoms, three asthmatic controls and three atopic subjects without bronchial hyperresponsiveness (BHR) who had no exposure to cleaning products. The study protocol consisted of a methacholine test, sputum induction and fraction of exhaled nitric oxide measurement (FENO) both at baseline and 24 hr after a 1-hr inhalation challenge with either placebo or bleach at a concentration of 0.4 ppm of chlorine. RESULTS: The inhalation of the placebo caused no bronchial reactions. Mean maximum fall in FEV(1) during challenge testing with bleach was significantly higher than the values obtained during the placebo challenge. Inhalation challenge with bleach elicited two isolated late asthmatic reactions and one dual asthmatic reaction. Of all the patients who underwent challenge testing with bleach, only one had a ≥2-fold decrease in methacholine PC(20) 24 hr after the challenge. No significant correlation was found between maximum fall in FEV(1) and PC(20) methacholine. Following challenge testing with bleach, no clinically significant changes in sputum cell counts or FENO were detected. CONCLUSIONS: These results suggest that bleach inhalation at a concentration of 0.4 ppm-a concentration below 8-hr permissible occupational exposure level-brings about a substantial decrease in FEV1 in subjects with and without BHR. Some subjects have a positive challenge response to bleach inhalation.
Subject(s)
Asthma/chemically induced , Bronchial Hyperreactivity/chemically induced , Chlorine/adverse effects , Occupational Diseases/chemically induced , Occupational Exposure/adverse effects , Adult , Age Distribution , Analysis of Variance , Asthma/epidemiology , Asthma/physiopathology , Bronchial Hyperreactivity/epidemiology , Bronchial Hyperreactivity/physiopathology , Bronchial Provocation Tests , Cohort Studies , Detergents/adverse effects , Environmental Monitoring/methods , Epidemiological Monitoring , Female , Humans , Incidence , Male , Maximum Allowable Concentration , Middle Aged , Occupational Diseases/drug therapy , Occupational Diseases/epidemiology , Reference Values , Respiratory Function Tests , Risk Assessment , Severity of Illness Index , Sex Distribution , Statistics, NonparametricABSTRACT
A 55-year-old herpetologist developed rhinitis, asthma, urticaria and anaphylaxis when handling 4 different viper snake venoms. Allergen characterizations were done using SDS-PAGE, IgE immunoblotting and IgE inhibition experiments. The most prominent immunoreactive proteins were analyzed by MALDI-TOF mass spectrometry, and peptide identity was demonstrated by homology with known peptide sequences. SDS-PAGE showed several protein bands ranging from 5 to 99 kDa in each of the 4 snake venoms. Immunoblotting demonstrated 4 IgE-binding bands in the Bothrops extract of about 60, 28, 14 and 7 kDa. The bands of 28 and 14 kDa were also present in Lachesis muta. Two IgE-binding proteins of about 50 and 35 kDa were found in Bothrops atrox and L. muta, respectively. A strong inhibition of IgE binding to immobilize Bothrops asper proteins was observed after preabsorption of sera with B. asper, B. atrox,Bothrops xanthograma and L. muta extracts. MALDI-TOF analysis showed a 14-kDa phospholipase and the 60- and 28-kDa proteins showed significant similarity with metalloproteinases. In this report we have characterized the snake venom allergens that can elicit IgE-mediated symptoms.
