Measurement of inflammatory mediators of eosinophils and lymphocytes in blood in acute asthma: serum levels of ECP influence the bronchodilator response

Abstract

The aim of this study was to assess the relevance of immunoinflammatory markers on the response to short acting beta(2)-agonist in acute asthma exacerbation. Thus, we measured serum eosinophil cationic protein (ECP) levels and sIL-2R at acute exacerbation in 52 adult patients with atopic asthma, and assessed forced expiratory volume in 1 s (FEV(1)) before and after the administration of aerosolized salbutamol. After a cumulative dose of salbutamol causing a 10% improvement in FEV(1) from baseline [CD10, i.e. cumulative doses of salbutamol (800 microg) causing an improvement in FEV(1) from baseline to 10%] the patients were divided into two groups: group A with CD <10 and group B with CD >10. The bronchodilator response, as defined by a DeltaFEV(1) (percentage of predictive value of FEV(1)) of > or =10 predictive value, was shown by 40% of the patients. After 200, 400 and 800 microg of salbutamol, significant differences of FEV(1) with respect to baseline values were, respectively, p = 0.049, 0.0039 and 0.0014. In contrast, no significant difference of the means of FEV(1) between the doses of salbutamol was observed. Significant differences of DeltaFEV(1) between 200 and 400 microg (p = 0.0002) and between 200 and 800 microg (p < 0.0001) were observed, but not between 400 and 800 microg of salbutamol. There were significant correlations between baseline values of predictive FEV(1) and serum ECP levels (rho = -0.60, p < 0.0001) and sIL-2R levels (rho = -0.35, p = 0.01) respectively. Besides, a correlation between DeltaFEV(1) and serum ECP levels (rho = -0.53, p < 0.0001) was observed, whereas no correlation was found between DeltaFEV(1) and sIL-2R. By analyzing differences between the two groups (A and B) for serum ECP levels, sIL-2R and blood eosinophil count, a significant difference was found for serum ECP levels. We conclude that subjects with acute exacerbation of asthma show high serum levels of ECP and sIL-2R and, more interestingly, that the response to brochodilator was higher in patients with lower serum ECP levels.