Partial reversibility of airflow limitation and increased exhaled NO and sputum eosinophilia in chronic obstructive pulmonary disease

We investigated the relationship between the reversibility of airflow limit ation, the concentration of nitric oxide (NO) in exhaled air, and the infla mmatory cells in the sputum of patients with stable chronic obstructive pul monary disease (COPD). We examined nine normal healthy control subjects and 20 nonatopic patients with COPD. Ten patients had no reversibility of airf low limitation (increase in FEV1 of < 12% and < 200 ml after 200 mug of inh aled salbutamol), and 10 patients had partial reversibility of airflow limi tation (increase in FEV1 of < 12% but > 200 ml after 200 mug of inhaled sal butamol). Exhaled NO levels were higher in COPD patients with partial rever sibility of airflow limitation than in those with no reversibility of airfl ow limitation (median 24 [interquartile range 15.3 to 32] ppb versus 8.9 [4 .6 to 14.7] ppb; p < 0.01). Compared with healthy control subjects, only CO PD patients with partial reversibility of airflow limitation had increased concentrations of sputum eosinophils. We conclude that, in patients with st able COPD, even a partial bronchodilator response to inhaled salbutamol is associated with increased exhaled NO and sputum eosinophilia, suggesting th at these patients may have a different response to treatment than do those without reversible airflow limitation.