Effect of inhaled leukotriene B4 alone and in combination with prostaglandin D2 on bronchial responsiveness to histamine in normal subjects.

The effect of intradermal injection of leukotriene B4 alone and in combination with prostaglandin D2 and E2 and the effect of inhaled leukotriene B4 in combination with prostaglandin D2 were studied in six non-asthmatic men. The intradermal injection of leukotriene B4 (1 microgram) alone caused no immediate or late response in five of the six subjects but greatly potentiated the flare response to intradermal prostaglandin D2 (0.5 microgram) and E2 (0.5 microgram) in all subjects. In contrast, inhaled prostaglandin D2 (6 micrograms) alone and in combination with inhaled leukotriene B4 (12 micrograms) caused no change in the response to inhaled histamine, measured 30 minutes and three and six hours after the inhalation. These findings provide no support for the suggestion that leukotriene B4 has an important role in causing bronchial hyperresponsiveness. The possibility that higher doses of inhaled leukotriene B4 may alter bronchial responsiveness cannot, however, be ruled out.