Release of Neutrophil Chemotactic Activity during Immediate Hypersensitivity Reactions in Humans

Abstract

Heat-stable, serum-derived chemotactic activity for neutrophils is shown in a human model of immunoglobulin [Ig] E-mediated asthma. Ragweed-sensitive subjects (26) underwent bronchial provocation challenge using ragweed and Mecholyl. Increased neutrophil chemotactic activity was found in serum tested from 5-30 min after a positive ragweed-inhalation challenge, but not after negative ragweed challenge. Appearance of neutrophil chemotactic activity did not reflect the effects of bronchospasm alone, because it was not found after bronchospastic responses to Mecholyl in the same subjects. There were no accompanying changes of serum complement activity nor evidence of inhibition of chemotactic activity by prior exposure to antisera to the 3rd and 5th components of complement. Ultrafiltration of serum showed chemotactic activity contained in fractions of at least 50,000 daltons. This may be the 1st demonstration of neutrophil chemotactic activity liberated during experimentally induced Ig-E-mediated asthma in humans.