Studies on Hypersensitivity to Bacterial Antigens in Intrinsic Asthma

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Abstract
Twelve children, aged 4-14 yr, with moderate to severe intrinsic asthma (IA) were studied. Symptom-score charts were used to confirm the relationship of acute respiratory tract infections to exacerbations of asthma. Hypersensitivity to 8 commonly occurring bacteria from the normal flora of the upper respiratory tract was studied by skin test, by crossed immunoelectrophoresis and by basophil histamine release in vitro, using ultrasonicates of the bacteria as antigens. Skin tests were all negative. All children contained low titers of precipitating antibodies against most of the bacteria, but in this respect they did not differ from normal children. Release of histamine was induced in leukocytes from the IA children by all, or most sonicates, while such reactions, were less frequent in control children. The pattern of responses indicated an element of specificity. There was no correlation to precipitating antibodies, or to the microbial flora of the children. Positive responses were characterized by low values of maximal histamine release, and by a tendency to fluctuations with time. Because of these fluctuations, and because the IA children and control children were tested on separate occasions, the real difference between these 2 groups cannot be ascertained. Water-soluble constituents of all the bacterial strains tested were capable of causing the release of histamine in vitro, but this phenomenon is not restricted to IA.