CLINICAL IMPLICATION OF PROTEIN-LEVELS OF IL-5 IN INDUCED SPUTUM IN ASTHMATIC-PATIENTS

To determine whether protein levels of interleukin-5 (IL-5) in induced sputum reflect the degree of eosinophilic inflammation, we evaluated the role of IL-5 on clinical characteristics in stable asthmatic patie nts. IL-5 level, differential eosinophil count, and level of eosinophi l cationic protein (ECP) in induced sputum were all significantly high er for asthmatics than for normal controls. Both eosinophil counts and ECP levels in induced sputum were inversely correlated with the degre e of airflow limitation (FEV1/FVC). In addition, patients with measura ble IL-5 in sputum had significantly more eosinophils, higher levels o f ECP in sputum, and lower FEV1 (percent predicted) than did patients with levels of IL-5 beneath the limit of detection. However, we found no significant difference in IL-5 levels between atopic and nonatopic asthmatics. IL-5 level in induced sputum is a good indicator of eosino philic inflammation in atopic and nonatopic asthmatic patients.