Plasma soluble urokinase-type plasminogen activator receptor level as a predictor of the severity of community-acquired pneumonia

The urokinase-type plasminogen activator receptor (uPAR) mediates various cellular activities and is involved in proteolysis, angiogenesis, and inflammation. The objective of this study was to investigate the association between soluble uPAR (suPAR) levels and community-acquired pneumonia (CAP) severity. A commercial enzyme-linked immunosorbent assay (ELISA) was performed to measure the plasma suPAR levels in 67 healthy controls and 75 patients with CAP. Our results revealed that plasma suPAR levels were significantly elevated in patients with CAP compared with the controls, and antibiotic treatment was effective in reducing suPAR levels. The plasma suPAR levels were correlated with the severity of CAP based on the pneumonia severity index (PSI) scores. Furthermore, lipopolysaccharide (LPS)-stimulation significantly increased uPAR expression in RAW 264.7 macrophages. In conclusion, plasma suPAR levels may play a role in the clinical assessment of CAP severity; these findings may provide information on new targets for treatment of CAP.