Effect of an inhaled adenosine A2A agonist 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 microg, 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 microg) 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.


CONCLUSIONS
The inhaled A(2A)-receptor agonist, GW328267X, 25 microg does not affect the allergen-induced LAR or the associated inflammatory response in asthma.
Luijk
B
B
Department of Pulmonary Diseases, Heart Lung Center Utrecht, University Medical Center Utrecht, Utrecht, The Netherlands.
van den Berge
M
M
Kerstjens
H A M
HA
Postma
D S
DS
Cass
L
L
Sabin
A
A
Lammers
J-W J
JW
D058917:Adenosine A2 Receptor Antagonists; D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000485:Allergens; D000730:Androstadienes / Q000008:administration & dosage*; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage*; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy* / Q000276:immunology*; D001985:Bronchial Provocation Tests; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D000068298:Fluticasone; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011336:Probability; D012016:Reference Values; D012129:Respiratory Function Tests; D018570:Risk Assessment; D016896:Treatment Outcome
D058917:Adenosine A2 Receptor Antagonists; D000485:Allergens; D000730:Androstadienes; D018927:Anti-Asthmatic Agents; D000068298:Fluticasone