Allergens detected in association with airborne particles capable of penetrating into the peripheral lung.

Extrinsic asthma is caused by exposure to airborne allergens. The diameter of airborne particles influences the depth of penetration and deposition fraction in the lung. In this study, we used an Andersen sampler to collect 9 different size ranges of airborne particles from a cat-containing and a cat-free room. We detected cat allergen 1 (CA1), the major cat allergen, using a rocket immunoelectrophoretic technique in larger particle size ranges (more than 5 mu). Using in vitro cat allergic donor basophil histamine release, cat-associated allergen activity was detected in particle size ranges from 10 to less than 1 mu in aerodynamic diameter. Control collections of airborne particles from a cat-free room showed little or no allergen activity, and nonatopic donor basophils did not release histamine in response to any of these samples. The P-K test (positive transfer test) confirmed findings of the other assays. We conclude that cat-derived allergens are associated with a large range of airborne particle sizes that penetrate into the peripheral lung.