Reduced activation of peripheral blood neutrophils after late-phase asthmatic responses but not in mild stable XXXX .

@entity748 @entity32 @entity1 @entity565 @entity26 @entity1454 @entity1576 @entity9536 @entity2263 @entity1224
BACKGROUND: Asthma is a process of @entity32 that may be worsened by the activation of neutrophils during acute exacerbations. OBJECTIVE: We investigated our hypothesis that changes in cellular activation may be detectable in peripheral blood (PB) during late-phase @entity565 and during clinical exacerbations. METHODS: Twenty-one stable @entity748 (9 on treatment with @entity2263 -agonists only, 12 using inhaled corticosteroids) and 10 nonasthmatic volunteers were first compared using flow cytometry to measure @entity2263 -integrin ( @entity9536 / @entity1454 ) expression. Production of reactive @entity26 species (ROS) was evaluated employing chemiluminescence. Next, 8 mild @entity748 were assessed using similar methods before and after allergen-induced late asthmatic reactions (LARs). Finally, 4 asthmatic subjects were evaluated over 3 months, and symptoms, peak expiratory flow (PEF) and ROS production were measured. Episodes of @entity1576 (exacerbations) were identified and their association with ROS production was examined. RESULTS: No differences were detected in adhesion molecule expression and ROS production comparing the normal and asthmatic groups. However, after development of the LAR, significant reductions in @entity9536 neutrophil expression (mean fluorescence intensity; MFI) were observed [before: 994 +/- 102 MFI (mean +/- SEM) versus after: 424 +/- 81 MFI; p < 0.01]. Furthermore, strong associations were found between decreases in @entity9536 and the severity of the LAR (r = 0.9; p < 0.02). In the clinical study, ROS production was significantly lower during exacerbations (median 43%; p < 0.05). Again, this measurement was significantly associated with reductions in PEF (r = 0.5, p < 0.03). CONCLUSIONS: In @entity1 with mild stable @entity565 , no differences in the activation of circulating neutrophils were detectable compared to nonasthmatic individuals. During episodes of @entity1224 , in the laboratory and in clinical disease, neutrophil activation decreased in PB, conceivably because activated cells may be preferentially sequestered in the lung.
