T CELLS IN THE PATHOGENESIS OF HUMAN ISOCYANATE ASTHMA

异氰酸酯是工业上广泛使用的高活性化合物， 职业性哮喘最常见的病因 但 异氰酸酯引起哮喘的机理还没有很好地确定。 有限的信息表明，异氰酸酯可以作为一个外国低 分子量半抗原，引起抗原特异性T细胞应答， 气道炎症 我们进行了异氰酸酯挑战研究， 描述肺部反应，并记录了晚期和/或 哮喘反应 气道活检显示炎症增加 主要是T细胞。 BAL和外周血显示增加 活化和/或记忆T细胞与异氰酸酯攻击。 这 根据这些信息，我们提出了以下假设：a） 异氰酸酯哮喘是由一种独特的气道炎症介导的， 以显著的T细胞异常为特征的应答，B）异氰酸酯 在易感个体中诱导抗原特异性T细胞应答， 和c）T细胞在肿瘤发病机制中的作用的知识 异氰酸酯哮喘可导致外周血标记识别 致敏、早期异氰酸酯哮喘和/或宿主易感性。 为了解决这些假设，我们提出：目标1）表征 气道活检、BAL和外周血中的炎症反应 异氰酸酯哮喘受试者和适当的对照组， 在特定的异氰酸酯挑战之后。 免疫组织化学，FACS 分析、RT-PCR、原位杂交和ELISA方法将 用于表征：a）表型、激活状态和解剖结构 T淋巴细胞的定位，B）T细胞活化的表达和 调节细胞因子，c）T细胞受体（TCR）Vbeta基因使用，和d） 内皮细胞粘附分子的表达和分布。 目标2） 表征异氰酸酯诱导的半抗原特异性T细胞应答， 体外 （a）确定扩散对策和扩散水平， BAL和外周血单核细胞的细胞因子产生 在用特定异氰酸酯缀合物刺激后，和/或 异氰酸酯缀合抗原呈递细胞和B）产生和 表征从气道培养的异氰酸酯特异性T细胞系 活组织检查 目的3）确定早期疾病的外周血标志物 和/或对异氰酸酯的敏感性， 更大的流行病学研究。 这些研究将提高我们的 了解异氰酸酯哮喘的发病机制，特别是 T细胞的作用，并可能适用于其他形式的哮喘。 这些 研究还应确定致敏、早期疾病 和/或主体对异氰酸酯的敏感性， 诊断和预防。

Isocyanates, highly reactive compounds used extensively in industry, are the most commonly reported cause of occupational asthma. However, the mechanisms by which isocyanates cause asthma are not well defined. Limited information suggests that isocyanates can act like a foreign low molecular weight hapten, causing antigen specific T cell responses and airway inflammation. We performed isocyanate challenge studies to characterize the lung responses, and have documented late and/or asthmatic responses. Airway biopsies showed increased inflammatory cells, primarily T cells. BAL and peripheral blood showed increased activated and/or memory T cells with isocyanate challenge. This information has lead us to formulate the following hypothesis: a) Isocyanate asthma is mediated by a distinctive airway inflammatory response characterized by prominent T cell abnormalities, b) Isocyanates induce an antigen specific T cell response in susceptible individuals, and c) Knowledge of the role of T cells in the pathogenesis of isocyanate asthma may lead to identification of peripheral blood mar(s) of sensitization, early isocyanate asthma, and/or host susceptibility. To address these hypothesis we propose to : Aim 1) Characterize inflammatory responses in the airway biopsies, BAL, and peripheral blood of subjects with isocyanate asthma and appropriate controls before and after specific isocyanate challenge. Immunohistochemistry, FACS analysis, RT-PCR, in situ hybridization, and ELISA approaches will be used to characterize the: a) phenotypes, activation status, and anatomic location of T lymphocytes, b) expression of t cell activating and regulating cytokines, c) T cell receptor (TCR) Vbeta gene usage, and d) expression and distribution of endothelial adhesion molecules. Aim 2) Characterize hapten-specific T cell responses induced by isocyanates in vitro. We will: a) Determine proliferation responses and levels of cytokine production of BAL and peripheral blood mononuclear cells following stimulation with specific isocyanate conjugates and/or isocyanate-conjugated antigen presenting cells and b) Generate and characterize isocyanate-specific T cell clines cultured from airway biopsies. Aim 3) Identify peripheral blood markers of early disease and/or susceptibility to isocyanates that eventually can be applied to larger epidemiologic studies. These studies should improve our understanding the pathogenesis of isocyanate asthma, in particular the role of T cells, and may be applicable to other forms of asthma. These studies should also identify markers of sensitization, early disease and/or host susceptibility to isocyanates that will enable early diagnosis and prevention.