Vuokko L. Kinnula and colleagues point out that until now, no disease marker for COPD currently exists, despite extensive efforts by scientists to find one.
Previous studies pointed to a prime candidate - surfactant protein A (SP-A), which has a major role in fighting infections and inflammation in the lung.
The researchers compared levels of a variety of proteins obtained from the lung tissues of healthy individuals, patients with COPD, and those with pulmonary fibrosis.
They found that the lungs of COPD patients contained elevated levels of SP-A.
The researchers also found elevated levels of SP-A in the sputum samples of COPD patients.
"This suggests that SP-A might represent a helpful biomarker in the early detection of COPD and other related disorders," the authors stated.
The study is published in the December 5 issue of ACS' Journal of Proteome Research.