HYPERSENSITIVITY TO CHIRONOMIDS (NON-BITING MIDGES) - LOCALIZATION OF THE ANTIGENIC DETERMINANTS WITHIN CERTAIN POLYPEPTIDE SEQUENCES OF HEMOGLOBINS (ERYTHROCRUORINS) OF CHIRONOMUS-THUMMI-THUMMI (DIPTERA)

Humans (99) who were in contact with larvae of chironomids were investigated; 43 developed respiratory, conjunctival or cutaneous hypersensitivity reactions upon exposure to airborne constituents of these insects. By RAST [radioallergosorbent test], RAST inhibition and skin tests, type I sensitization to Hb of chironomids was identified in 33 subjects of the symptomatic group. In 1 case additional proof for high-grade sensitization was obtained by bronchial provocation with as low as 0.2 .mu.g of 1 of the isolated Hb. RAST and skin-test investigations with fragments obtained by chemical and enzymatic cleavage of 2 of the homologous Hb led to localization of the antigenic determinants within the peptide sequences 1-31, 32-90, 91-101 and 109-131 of Hb CTT IV and within the sequence 64-98 of Hb CTT VI of C. t. thummi. Hb of chironomids are potent allergens in man. Chironomids must be considered in relation to environmental and occupational sensitization contributing to respiratory diseases.