Exhaled breath markers in COPD

The need to monitor inflammation in the lungs has led to the exploration of exhaled gases and condensates, that may assist in differential diagnosis of pulmonary diseases, assessment of disease severity and response to treatment [, , ]. A proof-ofconcept study often will involve an examination of effects on a surrogate marker that is not guaranteed to produce a quick readout, such as effects on, for example neutrophilia or neutrophil activation in chronic obstructive pulmonary disease (COPD).