Elevated levels of anti inflammatory IL-10 and pro inflammatory IL-17 in malignant pleural effusions

BACKGROUND Pleural effusions can be caused by highly different underlying diseases and are characterized by complex interactions of various local and circulating cells as well as numerous soluble parameters like interleukins (IL). Knowledge of this complex network can be helpful in order to make the differential diagnosis in known malignant pleural effusions and understand the underlying immunochemistry of each disease or condition. METHODS We investigated immunoreactive concentrations of Interleukin 10 (IL-10) and Interleukin 17 (IL-17) in malignant pleural effusions and peripheral blood from patients with bronchial carcinomas and other carcinomas, excluding other conditions such as congestive heart failure (CHF) and pneumonias in twenty four (24) patients (9 men/15 women), 37-74 years (mean:61) with already diagnosed malignant pleural effusions applying the ELISA method. RESULTS The SPSS 15 program for Windows was used. Quantitative analysis showed high concentrations of IL-10 and IL-17 in pleural fluid and blood. Even though IL-17 levels -both blood and pleural- were lower than IL-10's, statistical correlation between blood and pleural concentations was proven, confirming once more the systematic action of these cytokines. At the same time high IL-17 levels in malignant effusions shows maybe a new perspective in understanding the pathophysiology of malignant pleural effusions. CONCLUSIONS Our results confirm the pathogenetic role of these cytokines in malignant pleural effusions combining for the first time a pro- and an anti- inflammatory cytokine. The observation that IL-17 is elevated in malignant pleural effusions may give a new meaning in Virchow's remarks 100 years ago. Larger number of patients is needed to confirm our hypothesis.