Evidence for haemoglobins as common allergenic determinants in IgE‐mediated hypersensitivity to chironomids (non‐biting midges)

摘要

SummaryChironomids (non‐biting midges) are known to cause IgE‐mediated hypersensitivity in man. This study compares the cross‐reactivity between the chironomid midgeCladotanytarsus lewisi(lgreen nimitti), a widespread cause of allergy in the Sudan andChironomus riparius(=thummi, CTT) where larvae are used as pet fish food and where haemoglobins were previously shown to be major allergens. As withC.riparius, immature forms ofC.lewisialso contain allergenic material since skin test responses to larval, pupal and adult extracts were obtained in Sudanese individuals. Crossed radioimmunoelectrophoresis of the C.lewisilarval and pupal extracts indicate that they contain a higher proportion of the allergenic fractions than adults. Further evidence of common allergen determinants betweenC.lewisiandC. ripariuswere obtained by the demonstration of positive skin‐prick tests, in Sudanese patients, to extracts of larval, adult and isolated haemoglobin extracts ofC. riparius. Cross‐reactivity betweenC. lewisiandC. ripariuswas also demonstrable by RAST inhibition studies. A dose‐dependent inhibition was observed using both theC. lewisiadult midge RAST and theC. ripariushaemoglobin RAST, the two respective antigens, and sera from individuals hypersensitive to eitherC. lewisiorC. riparius. Due to the immunological cross‐reactivity found between these distantly related species, we conclude that chironomids should be seen as significant environmental and occupatio