IL-26是一种由免疫细胞产生的细胞因子，通过促炎/抑炎作用参与多种炎症性疾病，然而尚无关于恶性胸腔积液（MPE）中IL-26作用的报道。项目组前期研究表明肺癌及胸膜转移性病灶中IL-26及其受体的表达增加。MPE中IL-26的浓度显著高于其同源外周血；其中多种免疫细胞能表达IL-26，且水平高于其同源外周血，Th1和Th17细胞可能是其主要来源细胞；外源性TNF-α、IFN-γ、IL-22能促进外周血单个核细胞分泌IL-26。此外，IL-26能通过促进MPE中CD4+T细胞以及记忆T细胞分泌IL-22参与MPE的发生发展。IL-26尚可抑制肺癌细胞的凋亡，促进其增殖、迁移。本项目将进一步深入揭示MPE中IL-26的其他免疫细胞来源，肿瘤细胞与IL-26相互作用的具体机制，IL-26对淋巴细胞亚群的发生/分化及趋化活性的影响及机制，IL-26参与MPE的具体途径及其对MPE转归的影响。

IL-26 is a cytokine produced by immune cells that participates in a variety of inflammatory diseases through pro-inflammatory/anti-inflammatory effect, though there is no report about IL-26 participating in MPE yet. Previous studies in the project group showed the presence of IL-26 and its receptors in lung cancer and pleural metastatic lesions. Many immune cells in malignant pleural effusion (MPE) express IL-26, of which Th1 and Th17 cells may be the main source cells; exogenous TNF-α, IFN-γ, IL-22 can promote the secretion of IL-26 in peripheral blood mononuclear cells. IL-26 can promote the expression of IL-22 by Th cells in MPE, and IL-26 also has a significant effect on the apoptosis, proliferation and migration of lung cancer cells. On this basis, the project will further reveal the source of immune cells of IL-26 in MPE, the effect of tumor cells on IL-26 secretion and its mechanism, the generation/differentiation and chemotactic activity of IL-26 on lymphocyte subsets, the effects and mechanisms of IL-26 interact with human lung cancer cell lines and primary tumor cells in MPE. Furthermore, the interaction between IL-26 and immune cells, tumor cells and cytokines in MPE and the specific mechanism were explored, and the specific pathway of IL-26 involved in MPE and its effect on MPE outcome were revealed.