PREVALENCE OF INSECT ALLERGEN-SPECIFIC IGE IN ALLERGIC ASTHMATIC-CHILDREN IN CINCINNATI, OHIO

Airborne insect antigens can represent significant outdoor aeroallerge ns. In this pilot study, allergic asthmatic children were screened by RAST for IgE directed against common outdoor insects. Insects studied included ant, cricket, grasshopper, housefly and moth. Spiders were al so tested. Three different extraction procedures were compared to dete rmine which method(s) best preserves the allergenic proteins. RAST dis cs were made for each insect extract and sera from allergic, asthmatic and nonallergic, nonasthmatic children were tested. The allergic asth matic sera had a higher percentage of isotope binding than the nonalle rgic nonasthmatic sera for all insects tested. The number of subjects with a Phadebas RAST score of 2 or greater was significantly higher in the allergic asthmatic group for moth (16 of 37, 43%), housefly (7 of 30, 23%), cricket (8 of 41, 19%), and grasshopper (7 of 36, 19%). Onl y one of the 25 control sera had a score of 2 to moth; none of the con trol sera reacted to any of the other insects. Most positive sera test ed showed cross-reactivity between insects. A few sera, despite showin g positive RAST results to two different extracts, showed no cross-rea ctivity between the two extracts, suggesting that these sera contained species-specific IgE. These results indicate that a significant propo rtion of allergic asthmatic children have IgE that binds to extracts o f moth, cricket, grasshopper, and housefly. Further studies are needed to determine whether these insect aeroallergens can produce clinicall y significant symptoms in sensitized atopic individuals.