Plasma eotaxin level and severity of asthma treated with corticosteroid

Our understanding of asthma severity was advanced by the identification of biomarkers which account for differences in lung function impairment. We tried to examine the effects of corticosteroid treatment on known correlates of asthma severity including peripheral eosinophil counts, total IgE, IL-5, and eotaxin Levels in plasma. We compared these biomarkers among groups of stable asthmatics categorized by the dose of corticosteroid (N: steroid-free, n = 25; L: low-dose inhaled, n = 27; MH: medium or high-dose inhaled, n= 19; O: inhaled plus oral, n= 8). Next we compared these markers and peak expiratory flow rate (PEFR) in unstable asthmatics before and after treatment with steroids (n = 22). Eotaxin levels in the O group were higher than those in the N and MH groups (P < 0.05). Logistic regression analysis demonstrated that plasma eotaxin level was correlated with the severity of asthma defined by treatment intensity (P = 0.01) and % FEV1 (P = 0.04) while the other markers were not. Eotaxin levels did not change after steroid treatment in unstable patients, whereas eosinophil counts decreased in parallel with PEFR. Among biomarkers of asthma severity studied, plasma eotaxin level was not significantly affected by corticosteroid treatment, and was associated with the severity even in the presence of steroid therapy.