Bronchial responsiveness and leucocyte reactivity after influenza vaccine in asthmatic patients.

The hypothesis was studied that an increased bronchial responsiveness (BR) after viral infections in asthmatics may be related to a change in cellular functions. Histamine threshold and histamine release from leucocytes were measured in asthmatic children and healthy controls before and after administration of a live attenuated or an inactivated influenza vaccine. Live influenza vaccine did increase bronchial responsiveness (BR) to histamine in asthmatic children but not in healthy controls. The inactivated vaccine did not give rise to an increased BR. The releasability of histamine from leucocytes was not increased as a result of the immunisation.