The role of plasmacytoid dendritic cells in allergic asthma

为了开发新的、更有效的治疗策略来治疗过敏性哮喘，需要提高对过敏原介导的肺部炎症的理解。最近，我们发现浆细胞样树突状细胞（pDCs）可能是一个目标群体。在这个项目的第一阶段，这些pDCs被表型和功能表征。最重要的结果是，与健康对照相比，特应性哮喘患者外周血pDCs中FcεRIα的表达增加，过敏原激发后支气管内pDCs中该IgE受体链的表达增加。此外，我们首次发现在th2样细胞因子环境下分化的pDCs中IL-4的表达上调。这些结果导致假设，在过敏性哮喘中，pDCs可能作为效应细胞支持甚至放大过敏性炎症。这个新项目应该集中在这个假设上。因此，我们将研究高亲和IgE受体交联对pDCs不同成熟状态的影响。首先，naïve健康对照者和过敏性哮喘患者外周血pDCs将在mRNA、蛋白质和功能水平上进行广泛比较。为了分析更多分化的pDCs，将使用已建立的体外模型，在存在th2样细胞因子环境的情况下，将IL-3添加到naïve pDCs中以产生所谓的Th2-pDCs。为了分析这些数据的体内相关性，将采用已建立的分段过敏原攻击的人类哮喘模型。在体内th2环境中分化的支气管内pDCs将在过敏原攻击后从支气管肺泡灌洗中分离出来，然后在fc - ε - ri交联后进一步分析。我们期望这些数据将使我们能够明确pDCs在过敏性哮喘中是作为效应细胞还是作为免疫调节细胞发挥作用。最后，鉴于新的治疗策略的发展，我们希望确定哪些因素的中和、抑制或添加会增加Th2-pDCs的耐受性，并降低其th2效应的潜力。在这次尝试中，我们将进行Th2-pDCs的体外模型。

To develop novel, more effective therapeutic strategies for the treatment of allergic asthma an improved understanding of allergen-mediated lung inflammation is needed. Recently, we identified plasmacytoid dendritic cells (pDCs) as a possible target population. In the first period of this project these pDCs were phenotypically and functionally characterized. The most important results were an increased expression of FcεRIα on peripheral blood pDCs from atopic asthmatics compared with healthy controls and an increased expression of this IgE receptor chain on endobronchial pDCs following allergen provocation. In addition, we showed for the first time the expression of IL-4 by pDCs which was upregulated in pDCs differentiated in a Th2-like cytokine milieu. These results lead to the hypothesis that in allergic asthma pDCs may function as effector cells which support or even amplify allergic inflammation. This new project is supposed to focus on this hypothesis. Therefore, the effects of crosslinking of the high affinity IgE receptor on different maturation states of pDCs will be investigated. First, naïve peripheral blood pDCs from healthy controls and allergic asthmatics will be extensively compared on mRNA, protein as well as on functional levels. To analyse more differentiated pDCs an established in vitro model will be used where IL-3 is added to naïve pDCs in the presence of a Th2-like cytokine milieu to generate so called Th2-pDCs. To analyse the in vivo relevance of this data the established human asthma model of segmental allergen challenge will be employed. Endobronchial pDCs which have been differentiated in a Th2-milieu in vivo will be isolated from bronchoalveolar lavage after allergen challenge and then will be further analysed following FcεRI-crosslinking. We expect these data will enable us to make a clear statement whether pDCs function as effector cells or as immune regulatory cells in allergic asthma. Finally, in view of the development of novel therapeutic strategies we want to identify factors whose neutralisation, inhibition or addition will increase the tolerogenic potential of Th2-pDCs and decrease their Th2-effector potential. For this attempt the in vitro model of Th2-pDCs will be performed.