ALLERGEN CHALLENGE-INDUCED ENTRY OF ALPHA(2)-MACROGLOBULIN AND TRYPTASE INTO HUMAN NASAL AND BRONCHIAL AIRWAYS

Background: Microvascular-epithelial exudation of bulk plasma may char acterize inflammatory airway diseases. This study compares the acute a llergen challenge-induced mast cell and exudative responses in nasal n ad bronchial airways. The focus is on alpha(2)-macroglobulin as an ind ex of luminal entry of plasma exudates. Methods: Separate nasal and br onchial allergen challenges were carried out outside the pollen season in eight patients with pollen-induced seasonal allergic rhinitis. The levels of different-sized plasma proteins (albumin molecular weight, 66,000 d and alpha(2)-macroglobulin molecular weight, 725,000 d) and t ryptase were determined in pre- and postchallenge nasal lavage and bro nchoalveolar lavage (BAL) fluids. Diluent and increasing doses of alle rgen were sprayed into the right nasal cavity, and each challenge was followed by a nasal lavage (volume, 15 ml) with a ''nasal pool'' devic e (recovery, >80%). Endobronchial allergen challenge (individual doses ) and BAL (volume, 2 x 25 ml) were performed in a lobe bronchus throug h a fiberoptic bronchoscope (recovery, 30%). Saline challenge and BAL were carried out in the contralateral lung as control. Results: The le vels of albumin, alpha(2)-macroglobulin, and tryptase increased dose-d ependently in postchallenge and nasal lavage fluids (p < 0.05) and cor related to nasal symptoms. In particular, albumin and alpha(2)-macrogl obulin correlated (r = 0.98, p < 0.001). Both alpha(2)-macroglobulin a nd tryptase, but not albumin, were increased in BAL fluids from the al lergen-challenged side (p < 0.05). Conclusion: Local allergen challeng e causes luminal entry of tryptase and alpha(2)-macroglobulin in the n ose and bronchi of patients with allergy. We suggest that mass cell an d plasma exudation responses may be similar in human nasal and bronchi al airways and that albumin levels (in BAL fluids) may not well reflec t the exudation process in bronchial airways