OBJECTIVE

To assess the clinical significance of three different noninvasive airway inflammatory indices in induced sputum and exhaled breath condensate (EBC) from persistent asthmatic patients.

METHODS

Moderate and severe asthmatic patients were prescribed inhaled corticosteroids combined with long-acting beta(2) agonists for a month. The symptom scores and percentage of predicted value of forced expiratory volume in one second (FEV(1)) (FEV(1)%pred) were measured while the concentrations of H(2)O(2), NO(3)(-)/NO(2)(-), and cysteinyl-leukotriene E(4) (LTE(4)) in induced sputum and EBC were detected before and after therapy.

RESULTS

A total of twenty-five subjects with moderate and severe asthma were enrolled. By combined therapy for one month the asthma symptoms relieved and FEV(1)%pred improved significantly (P < 0.01). The concentrations of H(2)O(2), NO(3)(-)/NO(2)(-) and LTE(4) in induced sputum and EBC declined significantly (P < 0.01) although the concentrations were still higher than those at normal baseline. More marked reduction of H(2)O(2) and NO(3)(-)/NO(2)(-) compared to LTE(4) was observed. It was revealed that the concentrations of H(2)O(2)and NO(3)(-)/NO(2)(-) but not of LTE(4) in EBC were negatively correlated with FEV(1)%pred (P < 0.01) and positively with symptom scores. Such correlations were also found in H(2)O(2) in induced sputum with FEV(1)%pred and symptom scores as well as NO(3)(-)/NO(2)(-) in induced sputum with FEV(1)%pred. The improvement of FEV(1)%pred after treatment was positively correlated with the reduction of H(2)O(2) and NO(3)(-)/NO(2)(-) both in induced sputum and EBC. Correlation analysis also demonstrated three inflammatory indices were equivalent in induced sputum and EBC (correlation coefficient of H(2)O(2), NO(3)(-)/NO(2)(-) and LTE(4), 0.759, 0.826 and 0.653, respectively. P < 0.01).

CONCLUSIONS

(1) Combined therapy with inhaled corticosteroid plus long-acting beta(2) agonist significantly improves the clinical symptoms and lung function of patients with moderate and severe asthma companies with marked suppression of airway inflammation. (2) Both of EBC and induced sputum sampling are valuable noninvasive procedures for detecting asthma airway inflammation, however, EBC technique is superior in safety and reproducibility. (3) H(2)O(2) and NO(3)(-)/NO(2)(-) seem to be more sensitive indices in diagnosis and monitoring asthma compared to LTE(4).