Polymyxin B-induced basophil degranulation in atopic and non-atopic asthmatic patients

It is suggested that increased reactivity in asthma is not limited to the bronchi but also exists in the mediator releasing system. We have previously observed that the basophils of atopic asthmatics are degranulated by polymyxin B in vitro. The present study attempts to relate this basophil degranulation to atopy. The basophil degranulation test in polymyxin B was performed in 28 atopic and 23 non-atopic asthmatic patients and 10 healthy controls. In 20 pollen-sensitive asthmatics, the test was performed during the pollen season and repeated when the season was over. In patients the total level of IgE was measured by enzyme immunoassay. Basophil degranulation with polymyxin B was observed in 18 of 28 atopics and in 3 of 23 non-atopic patients. There were no differences in the magnitude of degranulation between the pollen season and when the season was over. The level of IgE did not correlate with the magnitude of basophil degranulation (correlation index = 0,23).