Natural exposure to pollen reduces the threshold but does not change the pattern of response to the allergen in allergic subjects

AbstractIt is known that exposure to seasonal allergen in sensitized asthmatics increases non-specific bronchial responsiveness, but it is controversial if exposure to seasonal allergen influences the presence and the severity of the late asthmatic response (LAR) to allergen.Fifteen asthmatic subjects sensitized to grass pollen performed a specific bronchial provocative test (sBPT) with Phleum pratensis extract before and during the pollen season. Changes of methacholine were also assessed.Allergen PD20FEV1significantly decreased during the pollen season with respect to outside (allergen PD20FEV1, geometric mean: 0·10 vs. 0·23 biological units;P