Developmental change of chironomid allergen during metamorphosis.

The development of allergen during metamorphosis of chironomids, Chironomus yoshimatsui and Tokunagayusurika akamusi, was studied by means of ELISA inhibition with pooled serum containing high titer of specific IgE to each adult midge. Extracts of C. yoshimatsui larvae and pupae did not inhibit the specific IgE antibody to adult C. yoshimatsui. Mature adult C. yoshimatsui extract had about 10 times more inhibitory substance than the young adult. Hemoglobin, however, was degraded during the metamorphosis as measured by spectrophotometry and HPLC. The inhibitory substance against specific IgE antibody to adult T. akamusi was identified as highest in female body, less in egg, and even less in wing, leg and male body. The size of the substance in egg and female body was estimated at greater than 500 kD of molecular weight.

Analysis of lymphocyte response to chironomid midge antigens in asthmatic and non-asthmatic individuals.

Chironomid antigens are currently one of the important allergens for bronchial asthma in Japan. We evaluated in vitro responses of peripheral blood lymphocytes (PBLs) to chironomid antigens and compared these responses with serum IgE levels. PBLs from adult asthmatic patients showed stronger proliferation in response to the extract of adult midges of Chironomus yoshimatsui compared with healthy adults. On the other hand, elevated PBL responses of child asthmatic patients to chironomid antigens were not observed. There was no significant correlation between PBL proliferation and the serum IgE level. Our results might suggest that elevated PBL proliferation in response to chironomid allergens has somehow important pathogenic roles in adult cases although this does not correlate directly with specific IgE production.

Detection of IgE antibodies to larvae and adults of chironomids by enzyme-linked immunosorbent assay.

Using the ELISA method, IgE antibodies to chironomid midges; Tokunagayusurika akamusi larva (TAL), T. akamusi adult (TAA), Chironomus yoshimatsui larva (CYL), C. yoshimatsui adult (CYA) and Chironomus plumosus adult (CPA), were measured in the sera of 36 children with bronchial asthma who visited Tamano City Hospital near Lake Kojiima in the Okayama prefecture. IgE antibodies to adult midges (TAA, CYA and CPA) were widely detected, but only few IgE antibodies to larvae (TAL and CYL). The amount of IgE antibody to CYA and to CPA correlated (P less than 0.001), but the amount of IgE antibody to TAA and to CYA or CPA did not. This suggests that the allergenicity of CYA and CPA is similar, but the allergenicity of TAA is independent of that of CYA or CPA. On the other hand, the ELISA inhibition test showed that TAA allergenicity was independent of that of TAL, CYL, CYA, CPA and the house-dust mite, Dermatophagoides farinae (Df). The inhibition test also showed that CYA and CPA had similar allergenicity, but differed from TAL, TAA, CYL and Df. This indicates that the allergenicities of chironomid midges change during the metamorphosis from larva to adult, and are not common among all species.