The importance of particle size in the bronchial response to inhaled allergen

Few teams have studied the effects of particle size on the bronchial response to inhaled allergen. Nonetheless, the aerodynamic characteristics of the particles carrying allergens may explain some of the differences observed between bronchial responses to different allergens, between responses during bronchial provocation tests (BPT) and to responses under realistic conditions. We have shown that the dose of allergen inducing symptoms in BPT is 20 times smaller when cat allergen is carried by particles measuring 10.3 μm in aerodynamic diameter than when carried by particles measuring only 1.4 μm. Accordingly, the immediate bronchial response to cat allergen appears to be localized in the proximal airways and should be studied in BPT with particles of 10 μm diameter. [Copyright &y& Elsevier]