Proteomic analysis of pulmonary edema fluid and plasma in patients with acute lung injury.

Proteomics is the large-scale analysis of protein profiles. This approach has not yet been reported in the study of acute lung injury (ALI). This study details protein profiles in plasma and pulmonary edema fluid (EF) from 16 ALI patients and plasma and bronchoalveolar lavage fluid (BALF) from 12 normal subjects. More than 300 distinct protein spots were evident in the EF and BALF of both normal subjects and ALI patients. Of these, 158 were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. In the plasma and EF protein profile of ALI patients, there were multiple qualitative changes. For instance, in all normal subjects, but in only one of the ALI patients, seven distinct surfactant protein A isoforms were evident. Nearly all ALI patients also had protein spots that indicate truncation or other posttranslational modifications. Several of these novel changes could serve as new biomarkers of lung injury.