TNF-α in the Pleural Fluid for the Differential Diagnosis of Tuberculous and Malignant Effusion

Abstract

Background : Determining the cause of an exudative pleural effusion is sometimes quite difficult, especially between malignant and tuberculous effusions. Twenty percent of effusions remain undiagnosed even after a complete diagnostic evaluation, including pleural biopsy. The activity of tumor necrosis factor-alpha (TNF-), which is the one of proinflammatory cytokines, is increased in both infectious and malignant effusions. The aim of this study was to investigate the diagnostic efficiency of TNF- activity in distinguishing tuberculous from malignant effusions. Methods : 46 patients (13 with malignant pleural effusion, 33 with tuberculous pleural effusion) with exudative pleurisy were included. TNF- concentrations were measured in the pleural fluid and serum samples using an enzyme-linked immunosorbent assay (ELISA). In addition, TNF- ratio (pleural fluid TNF- : serum TNF-) was calculated. Results : TNF- concentration and TNF- ratio in the pleural fluid were significantly higher in the tuberculous effusions than in the malignant effusions (p in the malignant and tuberculous pleural effusions were similar (p>0.05). The cut off points for the pleural fluid TNF- level and TNF- ratio were found to be 136.4 pg/mL and 6.4, respectively. The sensitivity, specificity and area under the curve were 81%, 80% and 0.82 for the pleural fluid TNF- level (p ratio (p level and TNF- ratio can distinguish a malignant pleural effusion from a tuberculous effusion, and can be additional markers in a differential diagnosis of tuberculous and malignant pleural effusion. The level of TNF- in the pleural fluid could be a more efficient marker than the TNF- ratio.