The aim of this study was to assess the relevance of immunoinflammatory markers on the response to short acting β2-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 (FEV1) before and after the administration of aerosolized salbutamol. After a cumulative dose of salbutamol causing a 10% improvement in FEV1 from baseline [CD10, i.e. cumulative doses of salbutamol (800 µg) causing an improvement in FEV1 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 ΔFEV1 (percentage of predictive value of FEV1) of ≧10 predictive value, was shown by 40% of the patients. After 200, 400 and 800 µg of salbutamol, significant differences of FEV1 with respect to baseline values were, respectively, p = 0.049, 0.0039 and 0.0014. In contrast, no significant difference of the means of FEV1 between the doses of salbutamol was observed. Significant differences of ΔFEV1 between 200 and 400 µg (p = 0.0002) and between 200 and 800 µg (p < 0.0001) were observed, but not between 400 and 800 µg of salbutamol. There were significant correlations between baseline values of predictive FEV1 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 ΔFEV1 and serum ECP levels (rho = –0.53, p < 0.0001) was observed, whereas no correlation was found between ΔFEV1 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.