th1 and th2 cytokine profiles in malignant pleural effusion

background: the alteration of th1 and th2 cytokine levels is the subject of controversy in pleural effusions caused by malignancy, a situation that favors a th2 immune response. objective: to examine the different levels of il-4 and il-10 (th2 cytokines), and il-2 and interferon-γ (ifn-γ) (th1 cytokines) in malignant and non-malignant pleural effusions. method: the cytokine levels in pleural fluid of 62 patients with malignant pleural effusion (44 with lung cancer and 18 with extrathoracic tumors), 8 with tuberculous and 8 with congestive heart failure pleural effusion were analysed using enzymelinked immunosorbent assays. results: il-2 was below the detectable concentration of the assay. a significant decrease in ifn-γ level was observed in malignant but not in congestive heart failure cases compared to tuberculous cases. il-10 levels were higher in malignant and tuberculous pleural effusions than in congestive heart failure pleural effusions, however, this difference did not reach the significant level. il-4 levels were also increased non-significantly in lung cancer pleural effusions compared to the other groups. conclusion: our results show a wide variation in il-4, il-10, and ifn-γ levels in malignant pleural effusions, a pattern which was not convincing enough to differentiate the cause of effusion.