ENVIRONMENTAL EXPOSURE TO ASPERGILLUS-FUMIGATUS ALLERGEN (ASP-F-I)

Aspf I is a major allergen produced by the mycelia of Aspergillus fumi gatus. It is not present in spores and can be used as a specific marke r for the detection of germination of this fungus. We investigated the domestic and outdoor concentration of Asp f I in Poole, U.K. and Char lottesville, VA, U.S.A. Asp f I was undetectable in 95% (281/296) of h ouse dust extracts and present at low levels (< 0.17 mug/g of sieved d ust, mean 0.038 mug/g) in the remainder. In contrast, Asp f I could be detected in 65% (15/23) of cultures of house dust, suggesting the pre sence of viable, but ungerminated, A. fumigatus in the majority of hom es. Asp f I was detectable in 80% (28/35) of extracts of leaves and co mpost, but present in these outdoor samples at low levels ( < 0.11 mug /g, mean 0.27 mug/g). Air sampling for Asp f I was undertaken before a nd after vigorous disturbances at indoor (n = 5) and outdoor (n = 6) s ites. Airborne Asp f I was not detected in domestic samples or in undi sturbed outdoor samples. Following disturbance it could be measured in outdoor samples (range 7-6 29 ng/m3). The results suggest that while exposure to A. fumigatus is common, exposure to Asp f I and germinatin g A. fumigatus is uncommon. It is probable that those individuals who develop antibody responses to Asp f I have been exposed to A. fumigatu s which has germinated in their respiratory tract.