Relationship between mite, cat, and dog allergens in reservoir dust and ambient air

Background: Standardized methods to measure allergen exposure are essential to assess the relationship between exposure, sensitization, and asthma. Mo st studies have measured allergen levels in reservoir dust, although air sa mples may be more representative as a measure of inhaled allergen. The aim of this study was to define the relationship between mite, cat, and dog all ergen content in the reservoir dust and the levels in the ambient air. Methods: Dust samples from the living-room floor (LF) and sofa (S) were col lected in 127 homes: 62 without and 65 with pets (31 dogs, 34 cats). Air sa mples were taken in the same room, with a high-volume pump for 1 h (flow 60 l/min). Der p 1, Fel d 1, and Can f 1 were determined by mAb-based ELISA. Results: Airborne Der p 1 was below the detection limit (0.8 ng/m(3)) in al l homes, with reservoir levels (GM and range) being 1.14 mu g/g (0.2-66) an d 1.15 mu g/g (0.2-127) in LF and S, respectively. Airborne Can f 1 was det ected in 40/62 homes without pets (range 0.6-12.4 ng/m(3)) and in all homes with dogs (range 0.5-99 ng/m(3)). In the multiple linear regression analys is, Can f 1 level in the LF was an independent correlate of the airborne Ca n f 1 (P = 0.01, homes with dogs; P = 0.04, homes without dogs). Fel d 1 wa s detected in the air in 16/62 homes without pets (range 0.16-1.8 ng/m(3)) and in all homes with cats (range 0.4-22.3 ng/m(3)). Fel d 1 level in the L F was an independent correlate of the airborne Fel d 1 in homes without cat s (P = 0.008), but airborne levels in homes with cats did not correlate wit h reservoir levels. Conclusions: The aerodynamics of each allergen must be taken into account w hen assessing exposure: while levels in reservoir dust are the best availab le index for mite allergens, airborne levels might be more suitable for def ining exposure to pets. If air samples are difficult to obtain, levels of C an f 1 and Fel d 1 in the LF samples should be used as a surrogate measure of personal exposure.