过敏性疾病是全球第六大慢性疾病，全球范围内的患病率约为22%。其中过敏性结膜炎为主的眼部疾病最为常见，是干眼、圆锥角膜等的重要病因，严重者甚至可能致盲。传统认为Th2细胞及其产生的细胞因子是引起过敏性疾病的主要原因，我们前期发现在过敏性结膜炎小鼠模型中，花粉通过角膜结膜上皮细胞Toll样受体4（TLR4）的固有免疫途径，激活Th2细胞引起过敏性炎症反应，同时Th9细胞及其转录因子PU.1, IRF4的表达水平升高，而免疫抑制因子IL-27能够阻断该过程。近年来研究发现，Th9细胞及其产生的IL-9在过敏性哮喘、过敏性皮炎等过敏性疾病中同样发挥了重要作用。因此我们假设在过敏性结膜炎模型中，花粉通过TLR4固有免疫途径激活Th9细胞分化及其相关因子表达，引起过敏性炎症反应，而IL-27可能通过抑制Th9细胞的表达，减轻过敏炎症反应，以期在治疗过敏性结膜炎或其他过敏性疾病方面找到一个切入点。

Allergic disease is the sixth largest chronic disease in the world, with a global prevalence of about 22%. Allergic conjunctivitis is one of the most common eye diseases, which develops into dry eye, keratoconus and even blind. It is traditionally believed that Th2 cells and the cytokines its produced are the main causes of allergic diseases. In the mouse model of allergic conjunctivitis, we found that pollen activated Th2 cells to cause allergic inflammation through the innate immune pathway of Toll like receptor 4 (TLR4) of corneal and conjunctival epithelial cells. And the expression of Th9 cells and its transcription factor PU.1, IRF4 were upregulated. The immunosuppressive factor IL-27 could block the process. In recent years, it has been found that Th9 cells and its cytokine IL-9 play an important role in allergic asthma, allergic dermatitis and other allergic diseases. Therefore, we hypothesized that in our allergic conjunctivitis model, pollen can activate Th9 cell differentiation and expression through TLR4 innate immune pathway, cause allergic inflammation, while IL-27 may inhibit this reaction by inhibiting Th9 cell expression, so as to find a breakthrough point in the treatment of allergic conjunctivitis or other allergic diseases.