Influence of cigarette smoking on inflammatory factor in sputum after inhaled corticosteroid treatment in asthma

Objective To investigate the impact of cigarette smoking on inflammatary factors in sputum including cell component,IL-8 and eotaxin,and the effect on responses to treatment with inhaled corticosteroids (ICS)in patients with asthma.Methods Thirty-eight outpatients with chronic stable asthma who visited from January 2009 to February 2010 were enrolled in the study.Twenty-three cases were nonsmokers and 15 cases were smokers.All of them were treated by daily inhaled budesonide,and[32 agonist when necessary.Induced sputum eosinophil and neutrophil proportion were measured,and the levels of interleukin(IL-8)and eotaxin in induced-sputum by enzymatic immunoassay(ELISA)were compared between non-smoking and smoking asthmatic patients.Results The eosinophil proportion was(2.0 ± 0.4)％ in smokers and(4.6 ± 2.5)％ in nonsmokers before therapy,and(1.1 ± 0.5)％ in smokers and(1.8 ± 0.6)％ in nonsmokers after therapy.The difference was statistical significant(F =15.271,P ＜ 0.05).The eotaxin was(3.5 ± 2.1)× 10-3 mg/L insmokers and(8.6 + 2.3)x 10-3 mg/L in nonsmokers before therapy,and(3.1 + 1.5)x 10-3 mg/L insmokers)and(3.6 ± 1.3)x 10-3 mg/L in nonsmokers after therapy.There was statistical significant(F =24.172,P ＜ 0.05).There were no significant difference on neutrophil proportion and IL-8 before and after treatment(F =1.563 and 1.793,respectively,Ps ＞ 0.05).Neutrophil proportion(F =9.632,P ＜ 0.05)and IL-8(F =5.720,P ＜ 0.05)in smokers were significantly higher than non-smokers,whereas eosinophil proportion (F =15.879,P ＜ 0.05)and eotaxin(F =12.365,P ＜ 0.05)in smokers were significantly lower than nonsmokers.Conclusion There was a significantly increase in inflammatary cells andfactors in induced-sputum in two groups after ICS treatment,but the effect in smokers was lower than in non-smokers.Neutrophil proportion and IL-8 were higher in induced sputum in smokers,whereas eosinophil proportion and eotaxin were higher in non-smokers. Key words: Smoking; Asthma; Corticosteroids; Induced sputum