Transforming growth factor beta-1 level in pleural effusion.

Objective: Transforming growth factor-beta1 is an important immunomodulator. The diagnostic role of TGF-beta1 has not been systematically investigated in pleural effusion.

Methods: A prospective clinical study of 45 patients (23 men, 22 women; mean age 49 +/- 21 years) with pleural effusion was performed. Of these patients, 19 had malignant pleural effusion, 14 had tuberculous pleural effusion, seven had empyema/parapneumonic pleural effusion, and five had transudative pleural effusion due to congestive heart failure. The concentrations of TGF-beta1 were measured by ELISA in all pleural fluid samples and in serum samples only from patients with malignant and tuberculous pleural effusions.

Results: The median TGF-beta1 levels of malignant, tuberculous and empyema/parapneumonic pleural effusions were 7.25 ng/mL, 7.81 ng/mL, and 9.75 ng/mL, respectively. There was no significant difference between them. The median TGF-beta1 level was 5.62 ng/mL in the transudate pleural effusion group and it was significantly lower than that in the empyema/parapneumonic group (P < 0.05). The pleural fluid TGF-beta1 levels did not correlate with cell profiles of the pleural fluid. The median serum TGF-beta1 levels in malignant and tuberculous pleural effusion groups were 7.38 ng/mL and 7.38 ng/mL, respectively. There was no significant difference between the levels of TGF-beta1 in paired samples of serum and pleural fluid.

Conclusions: This study shows that TGF-beta1 concentrations in exudative pleural effusions are higher than those in transudative effusions secondary to congestive heart failure but TGF-beta1 concentrations do not assist in differentiating exudative effusions.