Technical validation of controlled exposure to cat dander in the specialized particulate control environmental exposure unit (SPaC-EEU)

Hossenbaccus, L., Walker, T. & Ellis, A.K. Allergy Asthma Clin Immunol 21, 6 (2025). https://doi.org/10.1186/s13223-024-00928-1

To the Editor,

Consistent Fel d 1 concentrations and particle counts
were observed across runs in the Specialized Particulate
ControlEnvironmental Exposure Unit.

The Environmental Exposure Unit (EEU) is a 3500 square feet controlled allergen exposure facility located at the Kingston General Hospital site of Kingston Health Science Centre –in Kingston, Canada, which has been operating in this location since 1995. It is an internationally recognized model of prolonged allergen exposure, that can seat up to 120 participants at one time, with control of variables such as temperature, humidity, air flow, CO2 levels, and allergen type and concentration [1, 2]. The EEU is used to study mechanisms of, and treatments for allergic rhinitis (AR) and has been employed extensively with ragweed, grass, and birch pollens [3,4,5,6].

For the study of perennial allergens, the Specialized Particulate Control Environmental Exposure Unit (SPaC-EEU; formerly known as the house dust mite (HDM)-EEU) has been established.

This is an enclosed 760 sq. ft micro-controlled room within the EEU proper, and includes an adjacent anteroom, designed to hold between 5 and 45 participants simultaneously. It has undergone technical and clinical validation for use with HDM, successfully eliciting AR symptoms and biologic changes in only HDM-allergic, and not non-allergic, participants [7, 8].

As accurate and reproducible clinical models of prolonged cat allergen exposure are limited, we sought to evaluate the SPaC-EEU for use with cat dander [9]. We hypothesized that the SPaC-EEU and its equipment are suitable for the accurate and reproducible distribution of cat allergen over time.

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