Characterization of airway inflammation after repeated exposures to occupational agents.
BACKGROUND
Little is known about the comparative kinetics of eosinophil recruitment after exposure to low- and high-molecular-weight sensitizers in subjects with occupational asthma (OA).


OBJECTIVE
The aims of the study were to investigate the kinetics of changes in inflammatory mediators associated with eosinophil infiltration (IL-5 and eotaxin) and to examine the nature of the airway inflammation induced in response to different types of occupational agents.


METHODS
We investigated 15 subjects with OA caused by high- and low-molecular-weight agents. The subjects were exposed to increasing doses of the relevant occupational agent over 3 to 4 days until a 20% fall in FEV(1) occurred. Methacholine challenge and sputum induction were performed at the end of each day of exposure. Sputum samples were assessed for differential cell counts, including eosinophils, IL-5, and eotaxin messenger RNA.


RESULTS
There was an increase in sputum eosinophils, eotaxin, and IL-5 on the day preceding the occurrence of asthmatic reaction, although there was no change in functional parameters (FEV(1) and PC(20)). Increase in sputum eosinophils was more prominent in subjects exposed to low-molecular-weight agents than to high-molecular-weight agents.


CONCLUSIONS
Changes in eosinophils, IL-5, and eotaxin precede functional changes after exposure to occupational agents in subjects with OA. Eosinophil inflammation is a feature of exposure to both high- and low-molecular-weight agents. Induced sputum may be a useful tool in the early diagnosis of OA.
Lemière
C
C
Department of Chest Medicine, Hôpital du Sacré-Coeur de Montréal, and Meakins-Christie Laboratories, Montreal, Quebec, Canada.
Chaboilliez
S
S
Trudeau
C
C
Taha
R
R
Maghni
K
K
Martin
J G
JG
Hamid
Q
Q
D000328:Adult; D001249:Asthma / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000276:immunology*; D054413:Chemokine CCL11; D019742:Chemokines, CC; D002631:Chemotactic Factors, Eosinophil / Q000032:analysis; D016207:Cytokines / Q000032:analysis; D005260:Female; D006801:Humans; D007249:Inflammation / Q000276:immunology*; D015848:Interleukin-5 / Q000032:analysis; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D016273:Occupational Exposure / Q000706:statistics & numerical data; D013183:Sputum / Q000737:chemistry / Q000166:cytology
C515456:CCL11 protein, human; D054413:Chemokine CCL11; D019742:Chemokines, CC; D002631:Chemotactic Factors, Eosinophil; D016207:Cytokines; D015848:Interleukin-5