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Predictors of early‐ and late‐phase reactions to bronchial allergen challenge
Author(s) -
Haugaard L.,
Iversen M.,
Dahl R.
Publication year - 1997
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/j.1398-9995.1997.tb02420.x
Subject(s) - provocation test , histamine , medicine , eosinophil , eosinophil cationic protein , allergen , asthma , immunology , allergy , pathology , alternative medicine
The influence of inhaled steroids and predictive factors on the response to bronchial allergen challenge (BCA) was evaluated in. 80 asthmatics allergic to Dermatophagoides pteronyssinus (Der p). All underwent BCA with Der p and measurement of early (EAR) and late asthmatic reaction (LAR). The cumulative dose of allergen producing 20% fall in FEV 1 , in the EAR (PD 20 ) was calculated. Bronchial histamine provocation, conjunctival provocation test (CPT), and skin prick test with Der p extract were performed. Specific IgE to Der p in serum (RAST), blood eosinophil (EOS) count, serum eosinophil cationic protein, and eosinophil protein X were measured. Thirty patients (38%) were treated with inhaled steroids. All patients had at least a 20% fall in FEV 1 in EAR. Some 42% of nonsteroid‐ and 33% of steroid‐treated patients had LAR with fall in peak flow of at least 20%. For patients not treated with steroid, 35% of variation in PD 20 was explained by RAST and histamine reactivity, and 53% of variation of observed PD 20 could be predicted. The baseline FEV 1 , EOS, and EAR explained 28% of variation in LAR, and 28% of variation in observed LAR could be predicted. For patients treated with steroids, 38% of variation in PD 20 was explained by EOS and histamine reactivity, and only 18% of variation of observed PD 20 could be predicted. For patients treated with steroids, it was impossible to predict LAR. We conclude that to achieve a quantitative estimation of allergen‐specific EAR and LAR, BCA cannot be replaced by the tests used in this study. Treatment with inhaled steroids modifies the response to BCA, making quantitative prediction of EAR less accurate and prediction of the magnitude of LAR impossible.