Differential diagnosis of tuberculous pleurisy by measurement of cytokine concentrations in pleural effusion.

STUDY OBJECTIVE

Measurement of cytokine concentration in serum and pleural effusion may be useful in the differential diagnosis of tuberculous pleurisy.

PATIENTS AND METHODS

We compared the biochemical properties and concentrations of cytokines in serum and pleural effusion samples of 18 patients with tuberculous pleurisy, 7 patients with parapneumonic pleurisy, and 25 patients with malignant pleurisy.

RESULTS

A high value of adenosine deaminase (ADA) was observed in pleural effusion of patients with tuberculosis. The serum concentrations of interleukin (IL)-1-beta, IL-2, interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha were similar among the three groups. However, the concentration of IFN-gamma in pleural effusion was high in tuberculous patients, and that of TNF-alpha was high in tuberculous and parapneumonic pleural fluid, but both cytokines were low in malignant pleural fluid. The sensitivity, specificity and accuracy of IFN-gamma in the diagnosis of tuberculous pleurisy were 94%, 100% and 98%, respectively. Similarly, those of TNF-alpha for the diagnosis of infectious pleurisy including tuberculous and parapneumonic pleurisy were 88%, 80% and 84%, respectively.

CONCLUSIONS

Our results indicate that simultaneous measurement of IFN-gamma and TNF-alpha in pleural effusion is a useful diagnostic tool for differentiating tuberculous pleurisy from parapneumonic and malignant pleurisy.