New in vitro method for detecting asthma allergen. Counting reactive basophils after addition of allergen

Changes in the morphology and number of basophils were examined after the addition in vitro of house dust extract in cells from seventy-seven patients with bronchial asthma. Morphological changes (reactive basophils) showed a close relation to the end-point titrations of antigen in skin tests, RAST score and bronchial provocation tests, but changes in number of basophils did not. With a RAST score of 2 or greater the change in reactive basophils varied from 40 to 80% (mean 58.1%), which was much greater than seen in persons with no RAST, score 0. Patients with positive bronchial inhalation tests, showed 40 to 80% (mean 57.8%) reactive basophils, whereas persons with a negative bronchial challenge test showed a range of reactive basophils from 0 to 50% (mean 28.9%). The difference in percentage of reactive basophils between the positive and negative groups of persons tested by bronchial inhalation was statistically significant.