Levels of IL-18, IL-16, IL-8, eotaxin and the chymase activity in the sputum of asthmatics

AIM: To investigate the levels of IL-18, IL-16, IL-8, eotaxin and the chymase activity in the sputum of asthmatics. METHODS: IL-18, IL-16, IL-8 and eotaxin levels were detected with sandwich ELISA procedures and chymase activity was determined spectrophotometrically (410 nm) by the rate of hydrolysis of N-succinyl-L-Ala-L-Ala-L-Pro-L-Phe-p-nitroanilide (SAAPP). RESULTS: The specific chymase activities in the severe and moderate asthmatics were higher than that in controls. Native protease inhibitors α1-antitrypsin (α1-AT) and soybean trypsin inhibitor (SBTI) inhibited 71.9% and 72.1% enzymatic chymase activity, respectively. The levels of IL-18, IL-16, IL-8 and eotaxin were significantly elevated in the sputum of patients with acute asthma. There were correlations between the levels of IL-8 and IL-16 (r=0.55, P<0.05), IL-8 and eotaxin (r=0.41, P<0.05), IL-18 and IL-16 (r=0.64, P<0.01), IL-18 and eotaxin (r=0.66, P<0.01)，IL-16 and eotaxin (r=0.64, P<0.01), but they all failed to correlate with neutrophils, epithelial cells, lymphocytes and macrophages. CONCLUSION: The levels of IL-18， IL-16， IL-8， eotaxin and the activity of chymase were elevated in the sputum of the patients with asthma, indicating that they may play a role in the pathogenesis of asthma.