The study will be performed outside the pollen season. On a baseline visit, 2 to 7 days prior to control challenge, allergy skin prick tests and methacholine inhalation test will be done. Prior to first allergen challenge, skin titration will be done using tenfold dilutions of the allergen chosen for nasal challenges. Subsequent to baseline visit, a control challenge will be done, followed, a week later, by repeated NACs. NACs will be done over 4 consecutive days, in the morning. Nasal peak inspiratory flows (NPIF), oral peak expiratory flows (PEF), and symptoms will be recorded at baseline and at regular intervals over 7 hours post-challenge on each challenge day. Induced sputum and nasal lavage specimen will be obtained 7 hours following the control challenge and the first and last NAC.
