Junichi Chihara

Allergy to insects in Japan: III. High frequency of IgE antibody responses to insects (moth, butterfly, caddis fly, and chironomid) in patients with bronchial asthma and immunochemical quantitation of the insect-related airborne particles smaller than 10 μm in diameter☆

After recognizing that moth, butterfly, caddis fly, and chironomid were the insects predominantly found in our environment, reaginic sensitivities to these insects in patients with asthma were investigated with extracts of silkworm wing for the detection of moth and/or butterfly allergy, caddis fly wing for caddis fly allergy, and chironomid whole body for chironomid allergy. At least 50% of 56 randomly selected patients with asthma had positive intracutaneous reactions to these insect extracts, and at least 80% of the skin reaction positive patients had specific IgE antibodies. An immunochemical assay of these insect-related aeroallergens in the dust collected 18.6 m above ground revealed the presence in the air of insect-related particles less than 10 microns in diameter with two peaks a year, one in the spring (silkworm wing, 3.18 ng protein equivalent to that of the crude extract per cubic meter of air; caddis fly wing, 3.08 ng/m3; and chironomid whole body, 5.21 ng/m3) and one in the autumn (silkworm wing, 8.24 ng/m3; caddis fly wing, 4.74 ng/m3; and chironomid whole body, 18.19 ng/m3). Although we have no idea whether or not such peak values are enough to cause asthmatic symptoms, seasonal fluctuations of specific IgE antibodies to these insects appeared to be similar to those of atmospheric insect allergens measured by this method. These findings suggest that insects are widespread and common inhalant allergens.