RT Journal Article SR Electronic T1 A new naturalistic asthma model in the environmental exposure chamber to study mild asthmatics safely and consistently JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP P4046 VO 44 IS Suppl 58 A1 Anne Marie Salapatek A1 Erin Beattie A1 Piyush Patel YR 2014 UL http://erj.ersjournals.com/content/44/Suppl_58/P4046.abstract AB Background: A low dose naturalistic allergen challenge model to study mild asthmatics would aid in the development of effective drug therapies. We investigated both model specificity and SPT or IgE classification as a predictor of change in lung function and lower airway symptoms in asthmatics.Methods: A meta-analysis was conducted on 323 subjects (53 mild asthmatics) with a history of cat allergy and positive SPT to cat allergen. Subjects were exposed to airborne cat allergen in a naturalistic Environmental Exposure Chamber (EEC) model for 3 hrs over 4 consecutive days. FEV1 was assessed before and after EEC and asthma symptom scores were recorded every 30 mins in the EEC.Results: Low dose airborne naturalistic challenge resulted in: 1) A consistent drop in FEV1 over 4 days allergen challenge. Asthmatics have a greater reduction in FEV1 (L) over all days (p≤0.001). 2) Increase in SPT moderately predicts a larger decline in lung function. 3) Increase in IgE class (C) predicts a larger drop in lung function (ΔFEV1 (L)) with allergen exposure: IgE ≥ C1 = 0.56 ± 0.06L vs. 0.31 ± 0.02L (p≤0.001); IgE ≥ C2= 0.59 ± 0.06L vs 0.34 ± 0.02L (p≤0.001); and IgE ≥ C3=0.66 ± 0.08L vs 0.44 ± 0.03L (p=0.01) in asthmatics compared to non-asthmatics, respectively. 4) Asthma symptom scores were higher in asthmatics than non-asthmatics (Mean Score 3.23 ± 0.30 vs. 2.60 ± 0.12 (p=0.05)). 5) Neither SPT or IgE class is predictive of asthma symptoms with allergen exposure.Conclusions: The EEC Asthma Model represents a more naturalistic model for the study of asthma. IgE and SPT are useful to characterize asthmatic patients and safely predict their response in the EEC.