Bronchial Hypersensitization and Hyposensitization in Man

Abstract

Inhalation of allergenic extracts from a closed spirometer circuit has been used for testing directly the allergic sensitivity of the bronchi. The allergic sensitivity of the bronchi could be increased or decreased by varying the amt. of inhalant. Hyposensitization was achieved by inhalation of minute amts. of allergen which caused a mild but definite asthmatic reaction and by increasing these amts. gradually. Two cases of pure grass pollen asthma, 2 cases of other pollen asthma, 6 cases of house dust asthma and 3 cases of mould asthma have been hyposensitized by this method. In 11 other cases the result remained uncertain, and in 7 cases hyposensitization proved impossible. In the 2 cases of grass pollen no asthma occurred during the following season, but the eye and nose symptoms of hay fever recurred. Hyper-sensitization was caused by inadvertent overdosage. The bearing of these observations on our understanding of the clinical picture of asthma is discussed. The hypothesis is advanced that the spontaneous changes in the severity of allergic asthma may be the result of repeated interchanges of natural hypersensitization and hyposensitization. Suppression of the allergen-induced asthmatic attack by Isoprenaline did not interfere with the progress of hyposensitization nor did it prevent hypersensitization. It was not possible to induce an asthmatic attack with a bacterial vaccine.