Efficacy of air cleaners to reduce allergic responses to cat: A randomized clinical trial using an environmental exposure chamber.

BACKGROUND

Air cleaners improve indoor air quality by reducing pollutants and airborne allergens. Only a few clinical studies showed their efficacy in respiratory diseases in environmental exposure chambers (EECs).

OBJECTIVE

To assess the efficacy of the Dyson HEPA H13 filter (Big + Quiet Formaldehyde) air cleaner on allergic responses in cat-allergic patients.

METHODS

This single-center, randomized, double-blind, parallel-group study enrolled 30 GINA 1-2 cat-asthmatic patients with or without allergic rhinoconjunctivitis. Patients were included (Visit 1) according to their allergy and asthma history and skin prick testing for cat allergens. At randomization (Visit 2), patients presented early asthma response (EAR), during 2-h exposures to 80 ng/m3 of cat allergen in ALYATEC EEC. A second allergen exposure (Visit 3) evaluated the impact of air cleaners on bronchial, nasal and ocular responses as compared to placebo.

RESULTS

EAR was significantly delayed in the active group (p = 0.02). After 50 min of exposure, no patient developed EAR in the active group, compared to 53.3 % in the placebo group. FEV 1 rates were reduced in 40 % of EAR in the active group compared to 73.3 % in the placebo group (p = 0.06). Air cleaners reduced rhino-conjunctivitis by 52.2 % with a mean TSS of 1.6 compared to 3.3 in the placebo group (p = 0.03). Rhinitis responses were improved in the active group, compared to placebo (p = 0.03). Air cleaners decreased cat allergen from 79.6 ng/m3 to 14.2 ng/m3

CONCLUSIONS

Air cleaners improved clinical allergic responses during cat allergen exposures in ALYATEC EEC.