[The changes of NO2-./NO3-. level in sputum from patients with asthma and their clinical implications]

To evaluate the clinical applications of the detection of the stable end products of NO, nitrite and nitrate (NO2-./NO3-.) in sputum from patients with asthma.

45 patients with asthma at remission (group I, n = 15) or exacerbation state with mild attack (group II, n = 15) or moderate to severe attack (group III, n = 15), 15 cases of chronic cor pulmonale secondary to chronic bronchitis at exacerbation (group IV), and 20, normal control subjects (group V n = 20) were included in this study. NO2-./NO3-. in sputum and serum were measured by Griess reaction, while the eosinophil cationic protein (ECP) in sputum and pulmonary function were also measured in tested patients with asthma.

The median concentrations of sputum NO2-./NO3-. in group I, II and III were 85, 131 and 136 mumol/L respectively, all were significantly higher than that in controls (63 mumol/L); those of group II and III were significantly higher than that of group I, while that of group IV (33 mumol/L) was significantly lower than those of the asthmatic groups and the control. The level of NO derivatives in sputum was closely correlated with the degree of airflow obstruction and sputum ECP levels in patients with asthma at remission (r = -0.587, P < 0.05; r = 0.535, P < 0.01 respectively) and exacerbation (r = -0.485, P < 0.05; r = 0.563, P < 0.05 respectively). There was no significant correlation between serum and sputum NO2-./NO3-., and no significant correlation between serum NO2-./NO3-. and the degree of airflow obstruction. A significant decrease in the concentration of sputum NO2-./NO3-. was observed after therapeutic treatment of patients with moderate to severe attack (136 vs 93 mumol/L).

The level of NO2-./NO3-. in sputum may be a useful marker for monitoring the state of airway inflammation and assessing the therapeutic efficacy.