Responsiveness to prostaglandin F(2α) in atopic and nonatopic subjects. Comparison with histamine and methacholine responsiveness

The authors were unable to distinguish between hay fever and allergic asthmatic subjects on the basis of PGF(2α) responsiveness, despite the fact that these groups were clearly separable with histamine or methacholine. In addition, both allergic groups, hay fever and asthmatic subjects, were significantly more responsive to PGF(2α) than nonallergic normal subjects. The inability to discriminate between allergic hay fever and asthmatic subjects was therefore due to an exaggerated responsiveness to PGF(2α) relative to methacholine and histamine in the hay fever subjects. These findings suggest that atopy by itself, independent of its clinical expression as either asthma or hay fever, is associated with a form of exaggerated responsiveness elicited by PGF(2α) but not by other smooth muscle agonists, such as histamine or methacholine. Although the mechanism of this exaggerated responsiveness is not known, our findings are consistent with the thesis that an atopy-related hyperresponsiveness to PGF(2α) may involve mechanisms that differ from those responsible for hyperreactivity to methacholine and histamine.