Hyaluronic acid levels are increased in complicated parapneumonic pleural effusions

Abstract

Hyaluronic acid (HA) is a component of extracellular matrix and may play a role in the pleural inflammation which is implicated in parapneumonic effusions.The aim of the current study was to investigate HA levels in serum and pleura in patients with parapneumonic effusions. We prospectively studied pleural and serum levels of HA in 58 patients with pleural effusions due to infection (complicated and uncomplicated parapneumonic effusions), malignant effusions and transudative effusions due to congestive heart failure. In addition to HA, TNF-alpha and IL-beta levels were determined in pleural fluid and serum by ELISA. The median +/- SD HA levels (pg/ml) in pleural fluid of patients with complicated effusions (39.058 +/- 11.208) were significantly increased (p < 0.005), compared to those with uncomplicated parapneumonic effusions (11.230 +/- 1.969), malignant effusions (10.837 +/- 4.803) or congestive heart failure (5.392 +/- 3.133). There was no correlation between pleural fluid and serum HA values. Pleural fluid TNF-alpha levels (146 +/- 127 pg/mL) and IL-1beta levels (133.4 +/- 156 pg/mL) were significantly higher in patients with complicated parapneumonic effusions compared to patients with other types of effusion (p < 0.05). No significant association between HA and TNF-alpha or IL-1beta was found. CONCLUSIONS. HA may play a significant role in the inflammatory process which characterises exudative infectious pleuritis. Further investigation might reveal whether HA is a useful marker in the management of parapneumonic effusions.