Allergy
-
Allergic asthma is characterized by chronic recruitment of eosinophils in the airways. Once activated, eosinophils release toxic products, including eosinophil cationic protein (ECP), able to damage airway epithelial cells. To test the hypothesis that also in mild-moderate stable asthma, a significant eosinophil activation could occur, we studied 25 asthmatic patients (34 +/- 19 years old), of whom 18 were allergic (27 +/- 12 years) and seven nonallergic (42 +/- 10 years), with FEV1 values > or = 70% of predicted, and eight normal volunteers (controls, 33 +/- 11 years). ⋯ In BAL of asthmatic patients, positive correlations were found between eosinophil numbers and 1) ECP/Alb levels (r = 0.50, P = 0.020); 2) epithelial cell numbers (r = 0.50, P = 0.014). In asthmatic patients, a significant negative correlation was found between bronchial reactivity to MCh (log Pd15) and ECP/Alb levels in BAL fluid (r = -0.6, P = 0.005), whereas no correlation was found between log Pd15 MCh and BAL eosinophil or epithelial cell number (P > 0.1, each correlation). These data suggest that bronchial eosinophil recruitment and activation may occur also in mild-moderate stable asthma and that bronchial epithelium damage and airway responsiveness may be partially associated with the eosinophilic inflammatory reaction.