Upregulation of CD11b on Eosinophils in Aspirin Induced Asthma

Background: Although a challenge test using non-steroidal anti-inflammatory drugs (NSAIDs) is crucial for diagnosis of aspirin-induced asthma (AIA), it also has drawbacks in terms of possible side effects. Therefore, alternative in-vitro diagnostic methods for AIA are awaited. Methods: Nineteen stable non-AIA patients (9 males and 10 females; mean age, 49.4 ± 4.8 years), and 20 AIA patients (9 males and 11 females; mean age, 51.1 ± 4.8 years) were enrolled in this study. CD11b and CD16 expressions on the peripheral-blood granulocytes after administration of aspirin and different concentrations of PGE2 in vitro were examined using flowcytometry. Results: Aspirin induced a significant increase in CD11b expression on eosinophils (CD16 negative granulocytes) in 19 AIA patients and one non-AIA patient. Increase in CD11b expression on eosinophils by aspirin administration was suppressed by PGE2 in a dose-dependent manner. Conclusions: The measurement of CD11b expression on peripheral-blood eosinophils showed very high sensitivity and specificity of (−95%) in diagnosing AIA. Although this method requires laboratory facilities for flowcytometry, it may be very useful in diagnosis of AIA without side effects. In addition, PGE2 may be involved in regulation of CD11b expression on eosinophils by aspirin administration.