Technical specifications of the Global Allergy and Asthma European Network (GA(2)LEN) chamber: a novel mobile allergen exposure chamber

摘要

Background: Field trials are the traditional approach for clinical trials in allergy but are under criticism for lack of standardization as they are affected by uncontrollable parameters such as environmental conditions, pollen counts, or lifestyle. Stationary allergen exposure chambers with a defined concentration of allergens under stable and standardized environmental conditions have been used to overcome these restrictions but have not allowed multicenter studies. We here describe the technical specifications and validation of a novel mobile pollen chamber specifically designed for multicenter studies - the GA(2)LEN chamber. Methods: Two inter-connectable standard-sized container frames were used as a structural basis for the newly developed allergen exposure chamber. One container accommodates an observation room, also used as an office, and a changing room. The other container houses the test chamber itself and the technical installations. A customized air condition system was integrated and several environmental sensors were installed in the test chamber. Environmental tests have been performed at various outside conditions. The airflow in the test chamber was designed to prevent unspecific symptoms. To allow for an individual particle exposure at each seat, a new particle disperse and distribution system was developed, patented and validated. Results: Technical and clinical validation tests have been successfully performed with Phleum pratense, Betula pendula, and mixtures of Dermatophagoides farinae, and Dermatophagoides pteronyssinus. The newly developed particle disperse system enable individual verum and placebo exposure, an even particle distribution at every seating position. The built-in air-conditioner is able to generate a tightly controlled, standardized and comfortable environment and the airflow did not provoke clinically significant irritation to lower respiratory tract, nose, or eyes. The chamber transportation has proven to be flexible and cost-effective. Conclusion: The GA(2)LEN chamber provides a novel mobile exposure chamber technology for research and clinical trials allowing a fast, affordable, and standardized multicenter approach.