Bronchial allergen challenge with isolated major allergens of Dermatophagoides pteronyssinus: the role of patient characteristics in the early asthmatic response.
BACKGROUND
The use of allergen extracts will hamper studies into quantitative aspects of allergic responses because the precise amount of relevant allergen for each patient is unknown.


OBJECTIVE
We applied isolated IgE-binding components (major allergens) in the technique of bronchial allergen challenge to determine the role of patient characteristics in the early asthmatic response (EAR).


METHODS
In 30 patients with mild-to-moderate asthma, the EAR was investigated after inhalation of an isolated major allergen of Dermatophagoides pteronyssinus (i.e., Der p 1 [n = 16] or Der p 2 [n = 14]). The degree of early-phase bronchial responsiveness to allergen (the cumulated dose of allergen causing a 20% fall in FEV1 [PD20allergen]) was related to the degree of nonspecific bronchial responsiveness (the concentration of histamine causing a 20% fall in FEV1 [PC20histamine]) and the level of specific IgE or allergen thresholds as found in skin tests and basophil histamine release assays.


RESULTS
Twenty-seven patients with an immediate response during allergen and histamine challenges (deltaFEV1, > or = 20%) were analyzed. In these patients, a strong correlation was found between PD20allergen and PC20histamine (r = 0.81, p < 0.001). Weak correlations were found between PD20allergen and the level of specific IgE (r = -0.36, p = 0.07) or allergen thresholds as found in skin tests (skin prick test, r = 0.36 and p = 0.07; intracutaneous test, r = 0.49 and p = 0.01) or basophil histamine release assays (r = 0.37, p = 0.08). Moreover, no significant contribution of these indices of IgE-mediated hypersensitivity to the prediction of PD20allergen by multilinear regression models with PC20histamine was found.


CONCLUSIONS
In asthmatic patients allergic to house dust mites the degree of nonspecific bronchial hyperresponsiveness is the main determinant of early-phase bronchial responsiveness to allergen. In these patients the degree of allergic sensitivity does not contribute to the prediction of the EAR after allergen inhalation.
Department of Pulmonology, Academic Medical Center, University of Amsterdam, The Netherlands.
M J
MJ
van der Veen
C E
CE
Lopuhaä
R C
RC
Aalberse
H M
HM
Jansen
J S
JS
van der Zee
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology*; D000818:Animals; D039741:Antigens, Dermatophagoides; D001249:Asthma / Q000209:etiology / Q000276:immunology*; D001980:Bronchi / Q000276:immunology*; D001985:Bronchial Provocation Tests; D005260:Female; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D008925:Mites / Q000276:immunology*
D000485:Allergens; D039741:Antigens, Dermatophagoides; D006023:Glycoproteins