INFLAMMATORY CELL DISTRIBUTION WITHIN AND ALONG ASTHMATIC AIRWAYS

Asthmatic airways are infiltrated with inflammatory cells that release mediators and cytokines into the microenvironment. in this study, we evaluated the distribution of CD45-positive leukocytes and eosinophils in lung tissue from five patients who died with severe asthma compare d with five patients with cystic fibrosis. For morphometric analysis, the airway wall was partitioned into an ''inner'' area (between baseme nt membrane and smooth muscle) and an ''outer'' area (between smooth m uscle and alveolar attachments). Large airways (with a perimeter great er than 3.0 mm) from patients with asthma or cystic fibrosis had a gre ater density of CD45-positive cells (p < 0.05) and eosinophils (p < 0. 001) in the inner airway region compared with the same airway region i n small airways. Furthermore, in small airways, asthmatic lungs showed a greater density of CD45-positive cells (p < 0.01) and eosinophils ( p < 0.01) in the outer compared with the inner airway wall region. The se observations indicate that there are regional variations in inflamm atory cell distribution within the airway wall in patients with asthma that are not observed in airways from patients with cystic fibrosis. We speculate that this inflammatory cell density in peripheral airways in severe asthma may relate to the peripheral airway obstruction char acteristic of this condition.