OBJECTIVETo investigate the clinical significance of anaphylatoxin C3a in induced sputum in patients with asthma.

METHODSThe patients with acute exacerbation of asthma treated at our department between September, 2006 and February, 2007 were included in the study. The demographic data, medical history, levels of lung function and C3a levels in induced sputum were assessed.

RESULTSA total of 33 patients were included in the study. The level of C3a in induced sputum was significantly higher in patients with acute exacerbation of asthma (2.24 ng/ml, range 1.68-5.58 ng/ml) than that in patients with asthma remission (0.7 ng/ml, range 0.24-2.31 ng/ml, P<0.05). Sputum C3a levels in the remission patients were significantly higher than those in the healthy controls (0.12 ng/ml, range 0.07-0.39 ng/ml, P<0.05). The levels of C3a in patients with severe exacerbation (4.69 ng/ml, range 2.69-6.59 ng/ml) were significantly higher than those in patients with mild exacerbation (0.25 ng/ml, range 0.09-0.40 ng/ml) and moderate exacerbation (2.21 ng/ml, range 1.16-3.41 ng/ml) (P<0.01), and were significantly higher in patients with moderate exacerbation than in those in mild exacerbation (P<0.01). The level of C3a in induced sputum was positively correlated with the number of total cell count (r=0.718, P<0.05), eosinophils (r=0.495, P<0.05) and macrophages (r=0.600, P<0.05) in patients with acute exacerbation of asthma.

CONCLUSIONInduced sputum C3a level can serve as an important clinical biomarker for clinical asthma management.