MPO and chronic obstructive pulmonary disease: Additionally, NE and MPO levels in serum and BAL fluid were found to be significantly higher in the lung cancer patients, who have never smoked compared with the current smokers with COPD (NE serum 480.11 ± 19.05 vs. 132.51 ± 18.72, MPO serum 286.96 ± 9.94 vs. 183.42 ± 11.95, MPO BAL fluid 103.65 ± 5.19 vs. 68.43 ± 7.59, P < 0.05).