Effect of interleukin-17 on in vitro cytokine production in healthy controls and patients with severe sepsis.

BACKGROUND/PURPOSE: Interleukin (IL)-17 family members (IL-17A to IL-17F) are appearing to play key roles in host defense and inflammatory disease. Recently, several cytokines, such as IL-6, IL-10, IL-12, and transforming growth factor (TGF)-ß1, were shown to have vital roles in severe sepsis. However, the influence of IL-17 on these cytokine responses from peripheral blood mononuclear cells (PBMCs) is unclear. METHODS: Fifty-two patients who were admitted to our intensive care unit (ICU) because of severe sepsis were enrolled into this study. To validate experimental findings, 25 healthy controls were enrolled. Lipopolysaccharide-stimulated PBMCs with IL-17 or anti-IL-17 treatments were cultured for 24 hours. IL-6, IL-10, IL-12, and TGF-ß1 levels in supernatants were measured. RESULTS: The IL-12 production from stimulated PBMCs was increased after IL-17 treatment in both control and patient groups. Additional treatment of anti-IL-17 enhanced IL-10 production but decreased IL-12 production from stimulated PBMCs of healthy controls and patients with severe sepsis. CONCLUSION: IL-17 was helpful for inflammation in severe sepsis. Lack of IL-17 decreased IL-12 and enhanced IL-10 production from PBMCs, which resulted in immune imbalance.