Medline ® Abstracts for References 20,45
of 'Reactive airways dysfunction syndrome and irritant-induced asthma'
Cross-sectional assessment of workers with repeated exposure to chlorine over a three year period.
Gautrin D, Leroyer C, L'Archevêque J, Dufour JG, Girard D, Malo JL
Eur Respir J. 1995;8(12):2046.
Airflow obstruction has been described in workers who experienced symptoms after acute exposure to chlorine. Persistent bronchial hyperresponsiveness has also been assessed, but mainly in case studies. In this cross-sectional study, we have assessed the relationship between inhalational accidents ("puffs") involving chlorine and persistent symptoms as well as hyperresponsiveness in 239 out of 255 at-risk workers (94%). No relationship was found between persistent symptoms and the exposure variables studied. Forced vital capacity (FVC) was higher in subjects who had had no symptoms after a "puff", compared with those who had experienced mild symptoms. Forced expiratory volume in one second (FEV1) and FVC were significantly lower in subjects who experienced more than 10 puffs with mild symptoms than in subjects who reported no symptomatic puff. The presence of bronchial hyperresponsiveness was not related to exposure, but the methacholine dose-response slope showed a tendency to increased bronchial responsiveness with increased exposure. A significant difference was shown in subjects who experienced more than 10 puffs with mild symptoms. In this group of workers, repeated exposure to chlorine with acute respiratory symptoms was associated with a slight but significant reduction in expiratory flow rates, together with an increase in bronchial responsiveness, without long-term symptoms.
Dept of Chest Medicine, Hôpital du Sacré-Coeur, Montreal, Canada.
Long-term pathologic consequences of acute irritant-induced asthma.
Takeda N, Maghni K, Daigle S, L'Archevêque J, Castellanos L, Al-Ramli W, Malo JL, Hamid Q
J Allergy Clin Immunol. 2009;124(5):975.
BACKGROUND: Acute irritant-induced asthma (IrIa) or reactive airways dysfunction syndrome is caused by exposure to a high concentration of an agent. The long-term pathologic consequences of IrIa remain thus far unknown.
OBJECTIVE: The aim of our study was to investigate the chronic airway inflammation and remodeling that occur in association with IrIa.
METHODS: Ten subjects with a history of IrIa (mean interval of 10.9 years, minimum of 4 years, since the inhalational accident) underwent bronchoscopy followed by bronchoalveolar lavage and bronchial biopsies. Immunologic and morphologic data from patients with IrIa were compared with those of patients with mild to moderate asthma as well as healthy controls.
RESULTS: Bronchoalveolar lavage fluid analysis showed increased eosinophil and neutrophil counts in 30% and 60% of subjects with IrIa, respectively. In the supernatant of bronchoalveolar lavage, we found a significant increase in the majority of mediators compared with healthy subjects and a significant increase in eosinophilic cationic protein, IL-8, basic fibroblast growth factor, and matrix metalloproteinase 1 compared with control patients with asthma. Evaluation of basement membrane thickness (subepithelial fibrosis) demonstrated a significant increase in patients with IrIa compared with healthy subjects and subjects with asthma. Basement membrane thickness also significantly correlated with the PC(20) value. The epithelial cell detachment showed an elevated although not significant trend compared with subjects with asthma and control subjects. Immunocytochemical analysis demonstrated increases in the number of eosinophil cationic protein and TGF-beta1-positive cells compared with healthy controls.
CONCLUSION: This study provides evidence of a significant eosinophilic and neutrophilic inflammation as well as remodeling in IrIa many years after an inhalational accident.
Meakins-Christie Laboratories, McGill University, Montreal, Quebec, Canada.