The Effect of Level of Exposure to House Dust Mites on the Development of Asthma after Early Childhood Wheezing

Koh, Young Yull; Jeong, Jin Hwa; Lim, Hyung Suk

Abstract

PURPOSE
Many young children suffer from wheezing illness during infancy, and some of them experience wheezing frequently and develop bronchial asthma ultimately. It is not clear whether the level of exposure to allergens in the environment is a significant risk factor for asthma in this clinical setting. The aim of this study was to examine the effect of level of exposure to house dust mites on the development of asthma after early childhood wheezing.
METHODS
Asthmatic children(n=21) and nonasthmatic children(n=19) with the past history of wheezing illness during the first three years of age were recruited. Samples of house dusts were collected from the bedclothes in their bedrooms. We measured the amount of group I allergens from Dermatophagoides spp., Der f I and Der p I in house dusts by ELISA using monoclonal antibodies.
RESULTS
In asthmatic and nonasthmatic groups, the level of Der f I was higher than that of Der p I, although the difference was not statistically significant. The level of Der f I was 4.32 microgram/gm of dust(geometric mean; range of 1 SD : 0.61-30.48) in asthmatic group and 3.72 microgram/gm(0.50-27.42) in nonasthmatic group. The level of Der p I was 2.22 microgram/gm(0.33-14.96) in asthmatic group and 2.07 microgram/gm(0.31-13.77) in nonasthmatic group. The difference between the two groups was not significant for both allergens. When the total subjects were divided into atopic(n=21) and nonatopic(n=19) groups, there was significant difference in neither Der f I nor Der p I level between atopic and nonatopic groups.
CONCLUSION
Although personal atopy is important in the development of asthma after early childhood wheezing, the level of exposure to allergens in the environment may not be a significant risk factor for the development of asthma in this clinical setting.