Effect of an inhaled adenosine A2Aagonist on the allergen-induced late asthmatic response

Background: Adenosine receptor activation is suggested to play a role in asthmatic airway inflammation. Inhibition of adenosine receptors may have an effect on the late asthmatic response (LAR) after allergen inhalation and this mechanism could offer a potential new treatment in asthma.Methods: We evaluated the effect of an inhaled adenosine-(2A) (A(2A))-receptor agonist (GW328267X), 25 mu g, in 15 nonsmoking atopic asthmatics who underwent an inhaled allergen challenge following twice daily treatment for 1 week in a double-blind, placebo- and fluticasone propionate (250 mu g) controlled study.Results: In contrast to fluticasone, treatment with the A(2A)-receptor agonist neither significantly protect against the allergen-induced early and late asthmatic reaction, nor the accompanying inflammatory response as measured by sputum total cell counts, number of EG2+ cells, and the concentration of interleukin-8 and eosinophil cationic protein.Conclusion: The inhaled A(2A)-receptor agonist, GW328267X, 25 mu g does not affect the allergen-induced LAR or the associated inflammatory response in asthma.