Repeated aerosol exposure to small doses of allergen. A model for chronic allergic asthma.
To improve our understanding of the pathophysiology of chronic allergic asthma, we mimicked natural allergen exposure by giving tiny doses of dust-mite extract (equivalent to estimated daily exposure in a typical bedroom) in three weekly sessions for 4 wk. Nine mild asthmatic adults who were highly sensitive to dust-mite allergen participated in the study. Serial assessments of bronchial reactivity by methacholine challenge, pulmonary function, symptoms, and bronchodilator requirements were obtained. Seven of nine subjects had a twofold or more (median: 6, range: 2.7 to 25) reduction (p = 0.008) in PC20, after which saline inhalations were substituted for dust-mite extract. Bronchial reactivity returned to normal within 2 to 3 wk after cessation of dust-mite inhalations in all but one subject. Predosing FEV1 dropped 10% over 4 wk of provocation (p = 0.001) and 7 of 9 returned to prestudy level within 2 wk after dosing was stopped. Late-phase responses were seen in 6 of 9 subjects. We conclude that repeated aerosol exposure to dust-mite allergen in doses comparable to natural bedroom exposure is sufficient to adversely affect pulmonary function and bronchial hyperractivity in sensitized individuals. These changes are rapidly reversible. This low-dose provocational strategy provides an attractive model for the experimental study of allergic asthma. Arshad SH, Hamilton RG, Adkinson NF, Jr. Repeated aerosol exposure to small doses of allergen: a model for chronic allergic asthma.
Arshad
S H
SH
Department of Medicine, Division of Allergy and Clinical Immunology, The Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Hamilton
R G
RG
Adkinson
N F
NF
D000293:Adolescent; D000328:Adult; D000336:Aerosols; D000485:Allergens / Q000008:administration & dosage*; D000818:Animals; D039741:Antigens, Dermatophagoides; D001249:Asthma / Q000276:immunology / Q000503:physiopathology*; D016535:Bronchial Hyperreactivity / Q000503:physiopathology; D001985:Bronchial Provocation Tests; D002908:Chronic Disease; D004781:Environmental Exposure; D005260:Female; D005541:Forced Expiratory Volume; D006023:Glycoproteins / Q000008:administration & dosage*; D006801:Humans; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D008925:Mites
D000336:Aerosols; D000485:Allergens; D039741:Antigens, Dermatophagoides; D006023:Glycoproteins; D016210:Methacholine Chloride