Diagnosis and treatment of tuberculous pleurisy--with special reference to the significance of measurement of pleural fluid cytokines

Tuberculous pleurisy as well as malignant pleuritis is a representative disease presenting pleural effusion. The diagnosis of tuberculous pleurisy is made from examination of pleural effusion, but the sensitivity of smear or culture of Mycobacterium tuberculosis from pleural fluid is generally low. Although the pleural fluid concentration of adenosine deaminase (ADA) is useful in terms of sensitivity or specificity, the value could be high in empyema or rheumatoid pleuritis. Thoracoscopic biopsy of pleura is more sensitive rather than conventional percutaneous needle biopsy, but is more invasive. Tuberculous pleural effusion is caused by delayed allergy which macrophage and T-helper 1 cells mainly relate and the stimuli of bacterial body consecutively induces T-helper 1 cytokines. Pleural fluid interferon-gamma (INF-gamma) is important not only in pathogenesis but also in diagnosis. We demonstrated that INF-gamma is a more sensitive and specific indicator for tuberculous pleurisy than ADA using receiver operating characteristics (ROC) analysis. Cytometric bead array (CBA) is a tool to simultaneously measure abundance of various cytokines and is expected to be a very useful method to provide informations for understanding a feedback mechanism of cytokine network. It is needed to clear the immunity in pleural fluid and to establish the less invasive and more useful method to diagnose tuberculous pleurisy.