变应性鼻炎中M2巨噬细胞的作用机制

Allergic rhinitis (AR) is the most prevalent type I allergy and is characterized by a Th2-skewing inflammation. The regulatory T cells (Treg) have received much attention because of their impaired role in suppressing Th1 or Th2 phenotypes, which could be mechanisms underlying allergic disease. Recently, M2 polarization of macrophages has been linked to the persistence of asthma, but the phenotypes and function of macrophages in allergic rhinitis are not clear. In our preliminary experiments, we observed M2 macrophages increased significantly in AR patients, whereas M1 cells showed no difference between AR patients and healthy controls. Of interest, M2 frequency is fluctuated with severity of symptoms. Therefore, we hypothesize that M2 macrophage could be taken as an active biologic marker of Th2-dominated inflammation. The proposed study will characterize macrophage subsets distribution in allergic rhinitis patients. Healthy volunteers and patients with AR will be recruited. Their macrophage phenotypes will be determined by flow cytometry, immunohistochemistry and western blot. Then, transwell coculture and luminex will be performed to further explore the association of M2 macrophage with Treg and Th2 cells, respectively.We anticipate this study will shed light on mechanism(s) underlying allergic rhinitis and provide potential target for better treatment of allergic rhinitis.

变应性鼻炎（Allergic rhinitis，AR）是过敏原作用于特应性个体而激发的Th2细胞为主的鼻黏膜炎性疾病，发病机制复杂。作为天然免疫调节的重要细胞，巨噬细胞存在M1型和M2型，与T细胞免疫调节相联系。但不同亚型巨噬细胞在AR中的作用机制尚未阐明。我们前期工作发现AR患者外周血M2巨噬细胞数量比健康志愿者显著上升，并且同一个AR患者在症状发作期M2巨噬细胞数量显著高于症状缓解期，提示M2巨噬细胞与Th2型炎症反应严重程度相关。我们将以变应性鼻炎患者为研究对象，采集外周血、脐带血和鼻粘膜标本，用Transwell体外共培养、流式细胞术、Luminex检测等方法，观察M2细胞在AR患者的表达，研究其与临床症状的相关性，探讨M2细胞与调节性T细胞、Th2细胞间的调控关系，揭示脐带血M2细胞与母婴变应性疾病的相关性。本研究对丰富和补充AR发病机制有重要意义，亦可为AR的治疗提供新的靶点。

变应性（过敏性）鼻炎（AR）在我国发病率达到17.6%，是严重影响生活质量的常见慢性难治性疾病。巨噬细胞是天然免疫调节的重要细胞，既往研究从细胞体外实验、动物体内试验及人体内研究等不同层面支持以下结论：M2细胞在上、下气道Th2型炎性疾病中发挥正向促进作用。目前国内外关于M2巨噬细胞在AR发病中的作用尚未见报道，我们提出假说：外周血和/或局部鼻粘膜组织中M2巨噬细胞增多可能是AR患者发病的重要机制，且M2巨噬细胞数量的多寡与Th2型炎症反应的严重程度可能存在关联。.本课题以变应性鼻炎患者为研究对象，设立健康对照组，采集外周血和局部鼻粘膜标本，通过流式细胞术和免疫组化证明变应性鼻炎发病过程中M2巨噬细胞在外周血和局部鼻黏膜组织中较对照组显著增加。通过相关性分析，确认了M2巨噬细胞与鼻部症状总评分和鼻堵呈正相关。本研究检测了外周血血清中巨噬细胞相关的炎性因子，发现M2a相关的炎症因子在过敏组显著高于对照组，而M2c和M1相关的炎性因子在两组间无显著差异。M2a相关的YKL-40在变应性鼻炎患者显著增加，并与鼻痒症状评分正相关。该部分结果提示M2巨噬细胞和YKL-40可以作为监测AR严重程度及精准治疗的靶点。.本研究进一步应用IL-4和Der p刺激M0细胞，通过体外培养，发现在过敏组M0细胞向M2a方向分化，而并非向M2c和M1方向分化。我们进一步提取体外培养的巨噬细胞的RNA，发现M2a相关的基因在过敏组显著升高，而M2c和M1相关的基因在过敏组和对照组表达相似。本研究检测巨噬细胞体外培养上清液，发现上清液中炎性因子谱与外周血血清炎性因子谱相同。最后我们应用体外培养巨噬细胞所得的上清液与naïve T细胞共培养，发现过敏组naïve T细胞向Th2细胞分化，其释放的IL-4显著升高，而Th1分化在两组间无显著差异。上述体外实验证实了M2巨噬细胞与Th2细胞之间相互促进转化的关系，阐明了巨噬细胞作为沟通固有免疫和获得免疫的桥梁作用。