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.