Seasonal changes in mite allergen (Der I and Der II) concentrations in Japanese homes

Background: There has been no report on seasonal changes in Der II allergen in floor and bedding dust. Objective: The purpose of the study was to examine the extent of seasonal changes in Der I and Der II allergens in the floor and bedding dust found in houses. Methods: We measured the absolute concentrations of mite allergens in dust collected monthly for 1 year from both the floors and bedding of eight houses in Tokyo. Dust samples were obtained from eight families without regard to their allergy histories. The concentrations of the Der p I, Der f I, and Der II allergens were measured by fluorometric sandwich ELISA. Results: We found seasonal changes in the concentrations of these mite allergens. The highest concentrations of Der I (Del p I plus Der f I) and Der II (Der p II plus Der f II) were present from August to October, and the lowest ones from March to April. In floor dust, the mean highest concentrations of Der I and Der II (35.0 and 20.2 mu g/g of fine dust) were sevenfold and fivefold respectively, times the mean lowest concentrations. In bedding dust, the mean highest concentrations of Der I and Der II (51.3 and 29.6 mu g/g of fine dust) each were fourfold times the mean lowest concentrations. Conclusions: The patterns of seasonal changes in Der II in floor and bedding dust were similar to those of Der I.