Inhalation of
prostaglandin E2 (
PGE2) had been reported to prevent
allergen-induced bronchoconstrictor responses; however, the effects of inhaled
PGE2 on
allergen-induced airway
inflammation or hyperresponsiveness after
allergen are unknown. This study examined the effects of inhaled
PGE2 on
allergen-induced airway responses and
inflammation. Eight mild asthmatics with a dual airway response to inhaled
allergen were recruited into a double-blind randomized crossover study comparing the effects of inhaled
PGE2 (100 microgram) or placebo, on
allergen-induced changes in FEV1 measured for 7 h, induced sputum inflammatory cells, obtained at baseline, 7 and 24 h, and
methacholine airway responsiveness measured at 24 h after challenge. Inhaled
PGE2 attenuated the
allergen-induced early fall in FEV1 from 24.4 +/- 3.6% after placebo to 10.3 +/- 2.5% after
PGE2 (p = 0.002), the late fall in FEV1 from 21.2 +/- 2.7% after placebo to 12.6 +/- 3.6% after
PGE2 (p = 0.03),
allergen-induced
methacholine airway hyperresponsiveness (p = 0.03) and
allergen-induced increases in percent sputum eosinophils from 36.3 +/- 8.8% after placebo to 21.0 +/- 7.3% after
PGE2 (p = 0.01), percentage of EG2+ cells (p = 0.02), and percentage of metachromatic cells (p = 0.02). These results indicate that inhaled
PGE2 attenuates
allergen-induced airway responses, hyperresponsiveness, and
inflammation, when given immediately before inhaled
allergen.