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Bronchial allergen challenge in subjects with low levels of allergic sensitization to indoor allergens
Author(s) -
Witteman AM,
Jansen HM,
Van Der Zee JS,
Mulder M,
Aalberse RC,
Witteman AM
Publication year - 1999
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1034/j.1398-9995.1999.00962.x
Subject(s) - medicine , sensitization , histamine , allergen , dander , immunology , immunoglobulin e , allergy , asymptomatic , asthma , airborne allergen , house dust mite , antibody
Background: Low skin reactivity to common inhalant allergens is frequently found in asymptomatic individuals as well as in patients with respiratory complaints. However, most studies on bronchial allergen challenge concern patients with high levels of allergic sensitization. The present study was directed to bronchial reactions after allergen challenge in subjects with low skin reactivity to Dermatophagoides pteronyssinus or cat dander. Methods: Titrated intracutaneous skin tests, skin prick tests, specific IgE assays, histamine release on washed leukocytes, and bronchial histamine and allergen‐challenge tests were performed in 20 subjects with an intracutaneous skin test threshold for cat dander ( Felis domesticus ) or D. pteronyssinus above 0.1 BU/ml (mean wheal diameter in skin prick test with 10 000 BU/ml: 4.4 mm). Ten of the 20 patients had specific IgE below the detection limit in at least one of the three IgE assays which were done. Fifteen patients had a specific IgE level below 2 kU/l in all three tests. As a positive control group, the same parameters were studied in seven moderately sensitized patients with an intracutaneous skin test threshold below 0.1 BU/ml (mean wheal diameter with 10 000 BU/ml: 7.2 mm). Results: The 20 subjects with low levels of allergic sensitization had an early decrease in FEV 1 of 8.6% ( P <0.01) and a mean late decrease of 6.3% ( P <0.05). There was a trend for decrease in PC 20 histamine 24 h after allergen challenge (−0.4 doubling doses, P =0.09). Conclusions: In this group of subjects with low levels of allergic sensitization, a statistically significant early and late decrease in FEV 1 was found. However, the decrease in lung function was small and unnoticed by most patients. The increase in nonspecific bronchial hyperresponsiveness after bronchial allergen challenge did not reach statistical significance in the study group. The results indicate that allergen exposure in patients with low levels of allergic sensitization may lead to airways changes in the absence of acute symptoms.