RELATION BETWEEN THE BRONCHIAL OBSTRUCTIVE RESPONSE TO INHALED LIPOPOLYSACCHARIDE AND BRONCHIAL RESPONSIVENESS TO HISTAMINE

Background Bronchoconstriction has developed after inhalation of lipopolysaccharide in a dose of 20-mu-g in asthmatic patients and of 200-mu-g in normal subjects. This study set out to determine whether the bronchial response to lipopolysaccharide was related to non-specific bronchial responsiveness and atopy. Methods Sixteen subjects with a fall in specific airway conductance of 40% (PD40 sGaw) after inhaling up to 900-mu-g histamine inhaled 20-mu-g lipopolysaccharide (from Escherichia coli type 026:B6) a week after bronchial challenge with a control solution of saline. The bronchial response over five hours was measured as change in FEV1 and area under the FEV1-time curve. Results FEV1 fell significantly more after lipopolysaccharide than after diluent inhalation, the difference in mean (SE) FEV1 being 4-6% (5.4%); response was maximal 60 minutes after lipopolysaccharide inhalation and lasted more than five hours. Histamine PD20FEV1 and PD40sGaw correlated with the fall in FEV1 after lipopolysaccharide inhalation. There was no difference in the proportions of responders and non-responders to lipopolysaccharide who were atopic. Conclusion Lipopolysaccharide induced bronchial obstruction is associated with non-specific responsiveness but not with atopy.