Predictors of cat allergen (Fel d 1) in house dust of German homes with/without cats.
BACKGROUND
Exposure to cat allergen is a major risk factor for sensitization and the development of asthma in many parts of the world. The study was designed to examine the levels of cat allergen (Fel d 1) in homes of two German cities and to detennine predictors of Fel d 1 exposure.


METHODS
We collected dust samples from 405 randomly selected homes in Hamburg (n = 201) and Erfurt (n = 204). In each apartment dust samples were taken from living room floor (LR), bedroom floor (BR), and mattress surface (MA) using vacuum sampling and analyzed by two-site monoclonal antibody ELISA. Environmental variables were assessed by questionnaire to obtain information on factors supposed to have an impact on the Fel d 1 levels in house dust. The effects of possible predictors of Fel d 1 were assessed by multiple linear regression models.


RESULTS
Fel d 1 was present in 98% of the homes (395/405), ranging from 0.015 to 7.278 microg/g dust (GM 0.486 microg/g). The levels were similar in floors (GM for LR 0.575 microg/g and BR 0.469 microg/g) and in MA (GM 0.424 microg/g). Higher allergen concentrations (> 2 microg/g) were detected in 99% of the homes keeping cats, in 55% of homes that had had a cat during the last year, and in 28% of the homes without a cat. Fel d 1 levels were significantly higher in homes with a cat (628-682-fold, MA, floor) and in homes in which a cat had previously lived (11-12-fold, floor, MA) than in homes that never had a cat. Furthermore, after controlling for possible other confounders, Fel d 1 levels were significantly higher in summer and in homes with low frequency of cleaning and low ventilation rate.


CONCLUSIONS
It could be confirmed that keeping a cat has the highest impact on Fel d 1 concentration. Besides, a continuous influx of Fel d 1 in homes without cat, as a result of direct or indirect cat contact outside the home, is likely. High frequencies of dusting and ventilation might reduce cat allergens in homes with and without cats.
Friedrich-Schiller-University, Institute of Clinical Immunology, Jena, Germany. i5bafa@nds.rz.uni-jena.de
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B
Fahlbusch
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U
Gehring
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K
Richter
H E
HE
Wichmann
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J
Heinrich
D000485:Allergens / Q000032:analysis*; D000818:Animals; D002415:Cats; D004391:Dust; D005858:Germany; D006023:Glycoproteins / Q000032:analysis*; D006798:Housing; D006801:Humans; D011237:Predictive Value of Tests
D000485:Allergens; D004391:Dust; D006023:Glycoproteins; C059296:Fel d 1 protein, Felis domesticus