Evaluation of adenosine deaminase (ADA) and ADA1 and ADA2 isoenzyme activities in patients with pulmonary tuberculosis and tuberculous pleurisy

Objectives: Tuberculosis (TB) still remains an important medical problem due to high levels of morbidity and mortality worldwide. Tuberculous pleurisy is the most common form of extrapulmonary TB. Since tuberculous pleural effusion usually contains a low number of mycobacteria, the diagnostic sensitivity of both direct microscopy and pleural fluid cultures is relatively low. Methods: This study included 25 patients with pleural effusions (11 with pleural TB and 14 with nontuberculous etiologies), 35 patients with pulmonary tuberculosis (PTB) and 42 healthy subjects. Results: The mean plasma ADA level in patients with PTB was 19.2±3.3U/L that was significantly higher than the control group (10.4±0.6U/L). The difference between patients with pleural TB and the controls is also significant (18.2±2.5U/L versus 10.4±0.6U/L, p<0.05). A significantly higher activity of ADA1 and ADA2 in the blood plasma was observed in patients with PTB and pleural TB than those of the corresponding controls (p<0.05). Conclusion: This study concluded that pleural fluid ADA analysis could be an easy, cheap and highly sensitive and specific test for the diagnosis of pleural TB.