Decrease of complement hemolytic activity after an allergen-house dust-bronchial provocation test

Twenty-two children with bronchial asthma and positive skin tests to house-dust allergen were subjected to a bronchial provocation test with the allergen, and both bronchial reactions and serum complement hemolytic activity were measured at different intervals after the challenge. Changes in complement hemolytic activity did not correspond either with early or late bronchial reaction to the allergen. A reproducible drop in complement hemolytic activity after allergen challenge was observed in eight patients and could be prevented in four out of seven patients by sodium cromoglycate. The duration of early bronchial obstructive reaction was longer in tests where parallel complement changes were observed. (J ALLERGY CLIN IMMUNOL 70:306, 1982.) Although many studies have concentrated on the role of complement in the origin of asthma, available data are fragmentary and there is no general agreement on the role of complement in this disease. For example, Collerame et al.' have found postmortem C3 deposits in bronchial basement membranes in some asthmatic patients. Other indirect evidence concerning a possible relationship between the complement system and asthma is derived from the studies of Kay et al. ,* who noticed changes in serum C4 levels in asthmatics. These results, however, were not confirmed by others.3 More direct evidence for complement involvement in asthma was reported by Halprin et a1.,4 who noticed a decrease of complement hemolytic activity after bronchial challenge with fungal antigens in a patient with occupational asthma. Recently, a detailed study by Arroyave et a1.j presented evidence that hemolytic activity of complement was reduced shortly after bronchial challenge with allergen in three out of seven patients examined, and the same phenomenon was noticed in some cases