Improved effects of Carbocisteine on the residual eosinophilic inflammation in the distal airways of asthmatic patients

INTERVENTION: Carbocisteine Placebo CONDITION: Bronchial asthma PRIMARY OUTCOME: change of inflammatory marker in induced sputum(eosinophil,ECP,SP‐D,MMP‐9/TIMP‐1,TSLP) SECONDARY OUTCOME: IOS(R5,R20,R5‐R20,X5,Fres); pulmonary function(FVC, FEV1.0, FEV1.0%, %FEV1.0); FeNO; Asthma related QOL(ACT, AQLQ) INCLUSION CRITERIA: Observation phase Males and females more than 20 yrs (at time of consent) Outpatients Patients with mild or moderate persistent asthma (according to the classification of asthma severity) taking into account current treatment. Patients with at least one asthma exacerbation in the 12 months prior to the observation phase. Patients with a morbidity period of one yr or more prior to the observation phase. Patients who have not smoked for one yr or more prior to the observation phase. An unequivocal diagnosis of bronchial asthma.