Decay of house-dust mite allergen Der f 1 at indoor climatic conditions.
BACKGROUND
The decay of house-dust mite allergens is important for the outcome of avoidance measures for house-dust mite-allergic patients.


OBJECTIVE
To quantify the stability of Der f 1 from mattress dust when exposed to domestic conditions.


METHODS
Three samples of mattress dust were individually homogenized and divided into 64 subsamples. Mites were killed by freezing for 48 hours at -30 degrees C. The subsamples were exposed in eight homes, three storerooms, and one greenhouse, where temperature and relative humidity were recorded. Der f 1 was determined in extracts of subsamples (enzyme-linked immunoadsorbent assay) at 0, 3, 12, and 24 months.


RESULTS
In the three samples of mattress dust, the initial concentrations of Der f 1 (mean +/- standard deviation; STD) were: 169 (12), 3.9 (0.4), and 31 (2.6) microg/g, respectively. Median half-life of Der f 1 in the mattress dust samples was 10 years in the exposure homes, 18 years in the store rooms, and 1.0 year in the greenhouse. No correlations among preserved Der f 1 and temperature, relative humidity, and absolute humidity in homes were found (Spearman rank correlation test).


CONCLUSIONS
Natural decay of Der f 1, with an estimated half-life of 10 years at housing conditions, has no practical consequence in reducing allergen exposure. Therefore, avoidance measures should include an active removal of the allergens.
kirstensidenius@dadlnet.dk
Kirsten E
KE
Sidenius
Thorkil E
TE
Hallas
Jørgen
J
Stenderup
Lars K
LK
Poulsen
Holger
H
Mosbech
D016902:Air Pollution, Indoor; D000485:Allergens / Q000378:metabolism*; D000818:Animals; D039741:Antigens, Dermatophagoides; D006023:Glycoproteins / Q000378:metabolism*; D008925:Mites / Q000276:immunology*; D013696:Temperature
D000485:Allergens; D039741:Antigens, Dermatophagoides; D006023:Glycoproteins