Background. We investigated the role of cytokines [tumor necrosis factor-a (TNF-a), interleukin-1 b (IL-1b), macrophage inflammatory proteins 1 b (MIP-1b), granulocyte-macrophage colony stimulating factor (GM-CSF), IL-15] in the evaluation of pleural effusion etiology. Methods. Using commercially-available ELISA kits, concentrations of these cytokines were measured in the pleural fluid and peripheral blood of patients with malignant effusions (n=51), parapneumonic effusions (n=7), tuberculous pleurisy (n=8), and transudative (n=8) effusions due to congestive heart failure or liver cirrhosis. Carcinoembryonic antigen (CEA) levels were also checked and used for comparison. Results. The results showed that 75% of blood TNF-a and 50% of effusion TNF-a, 90% of blood IL-1b and 67.5% of effusion IL-1b, and 97.5% of blood GM-CSF and 55% of effusion GM-CSF, were below minimal detectable concentrations, while 92.5% of blood IL-15 and 100% of effusion IL-15, and 95% of blood MIP-1b and 92.5% of effusion MIP-1b, were detectable. There was no significant difference in cytokine levels among a subgroup of patients with benign pleural effusion, in either the pleural fluid or peripheral blood; however, the pleural fluid TNF-a and IL-15 levels were higher in TB pleurisy (p=0.048 and 0.045, respectively), and blood MIP-1b levels were lower in patients with transudates. In general, the pleural fluid cytokine levels were higher than the blood levels, if they were detectable, in both the benign and malignant effusions. However, MIP-1b was higher in the peripheral blood than in the pleural fluid in patients with malignant effusion (p=0.009). None of these cytokines could be used for the differential diagnosis of benign and malignant pleural effusion (p>0.05), in either the pleural fluid or the peripheral blood, except for pleural fluid TNF-a, which was relatively higher in benign disease (p=0.028). On the other hand, there were significant differences in the CEA levels in the peripheral blood (p=0.012) and pleural fluid (p=0.001) of benign and malignant diseases. Conclusions. These findings suggest that pleural fluid CEA levels are still better than cytokines for the differential diagnosis of benign and malignant pleural effusion.
Background. We investigated the role of cytokines [tumor necrosis factor-a (TNF-a), interleukin-1 b (IL-1b), macrophage inflammatory proteins 1 b (MIP-1b), granulocyte-macrophage colony stimulating factor (GM-CSF), IL-15] in the evaluation of pleural effusion etiology. Methods. Using commercially-available ELISA kits, concentrations of these cytokines were measured in the pleural fluid and peripheral blood of patients with malignant effusions (n=51), parapneumonic effusions (n=7), tuberculous pleurisy (n=8), and transudative (n=8) effusions due to congestive heart failure or liver cirrhosis. Carcinoembryonic antigen (CEA) levels were also checked and used for comparison. Results. The results showed that 75% of blood TNF-a and 50% of effusion TNF-a, 90% of blood IL-1b and 67.5% of effusion IL-1b, and 97.5% of blood GM-CSF and 55% of effusion GM-CSF, were below minimal detectable concentrations, while 92.5% of blood IL-15 and 100% of effusion IL-15, and 95% of blood MIP-1b and 92.5% of effusion MIP-1b, were detectable. There was no significant difference in cytokine levels among a subgroup of patients with benign pleural effusion, in either the pleural fluid or peripheral blood; however, the pleural fluid TNF-a and IL-15 levels were higher in TB pleurisy (p=0.048 and 0.045, respectively), and blood MIP-1b levels were lower in patients with transudates. In general, the pleural fluid cytokine levels were higher than the blood levels, if they were detectable, in both the benign and malignant effusions. However, MIP-1b was higher in the peripheral blood than in the pleural fluid in patients with malignant effusion (p=0.009). None of these cytokines could be used for the differential diagnosis of benign and malignant pleural effusion (p>0.05), in either the pleural fluid or the peripheral blood, except for pleural fluid TNF-a, which was relatively higher in benign disease (p=0.028). On the other hand, there were significant differences in the CEA levels in the peripheral blood (p=0.012) and pleural fluid (p=0.001) of benign and malignant diseases. Conclusions. These findings suggest that pleural fluid CEA levels are still better than cytokines for the differential diagnosis of benign and malignant pleural effusion.