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

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.

Major house dust mite allergen, Der p I, activates phospholipase D in human peripheral blood mononuclear cells from allergic patients: involvement of protein kinase C

The major house-dust-mite allergen, Der p I, stimulates the phospholipase D (PLD) in peripheral blood mononuclear cells (PBMC) from allergic patients with maximal responses after 30 min exposure. At 30 min, Der p I stimulated PLD activity by 1.4-fold in mild, 1.6-fold in moderate and 2-fold in severe allergic patients over control values (p < 0.05). When the cells were pretreated for 24 h with phorbol myristate acetate to down-regulate protein kinase C (PKC), PLD stimulation by Der p I was largely abolished. These results indicate that in PBMC from allergic patients, Der p I can stimulate PLD activity, and that PKC activation is involved in this stimulation.