The Prostaglandin E Agonist, Misoprostol, Inhibits Airway Il-5 Production In Atopic Asthmatics

Background: Prostaglandin E-2 is a potent immunomodulator that inhibits the early and late bronchoconstriction to inhaled allergen, as well as inhibiting the acute allergen-induced release of mediators into the human airway. To determine if the stable prostaglandin E agonist misoprostol could alter the late allergic formation of mediators we measured the appearance of eosinophils and key cytokines in the bronchoalveolar lavage fluid 24 h after allergen instillation.Methods: Six atopic asthmatics underwent bronchoscopy, alveolar lavage and antigen instillation followed 24 h later by bronchoalveolar lavage. Eosinophil counts were done, together with measurements of IL-4, IL-5, eotaxin, RANTES and cysteinyl leukotrienes by immunoassay. The study was done in randomized blinded fashion while the volunteers took placebo or 600 mug of misoprostol four times a day (QID).Results: Misoprostol significantly decreased the appearance of IL-5 late after allergen challenge. Eotaxin levels were reduced, but not statistically significantly. Eosinophil number, RANTES, eosinophil cationic protein and cysteinyl leukotrienes were not altered by misoprostol.Conclusions: Misoprostol reduces the formation of IL-5 late after allergen challenge, perhaps by inhibiting eosinophil, mast cell, and/or T lymphocyte production of IL-5. Despite decreases in IL-5 and eotaxin, eosinophils were recruited and activated by allergen. (C) 2002 Elsevier Science Inc. All rights reserved.