Role of mycobacteria in sarcoidosis immunopathogenesis

描述（由申请人提供）：结节病是一种病因不明的疾病，病理特征为非干酪化肉芽肿，最常累及肺、皮肤、淋巴结和眼睛。与结节病具有相似病理和免疫特征的综合征，如慢性铍病、过敏性肺炎和结核病，说明肉芽肿性疾病可能或可能具有感染性病因。我们对石蜡包埋的结节病和对照标本进行PCR分析，检测分枝杆菌16S rRNA和rpoB的存在。我们在60%的肉样肉芽肿中发现分枝杆菌核酸的证据，而在对照组中没有发现分枝杆菌核酸（p<0.00002，卡方）。16S rRNA和rpoB扩增子的序列分析显示存在一种新的分枝杆菌，其基因与结核分枝杆菌（MTB）相似（99%的位置同一性）。我们扩大了我们的工作，包括来自范德比尔特大学和美国其他地区的10个冷冻结节病和10个对照组织。我们在50%的冷冻结节病标本中发现了分枝杆菌核酸，而在对照组中没有发现分枝杆菌核酸（p<0.0325，双尾Fisher检验）。最近，我们对结节病（n=10）和对照（n=9）外周血单个核细胞（PBMC）进行了ELISPOT检测。我们在70.0%的结节病标本中发现MTB katG肽的免疫识别，而没有阴性对照标本（p=0.01，方差分析）。中心假设是结节病是对分枝杆菌感染在遗传易感宿主的免疫反应。我们成立了一个全国性的合作项目，包括国家犹太医学和研究中心、范德比尔特大学医学院和科罗拉多大学博尔德分校。合作的目的是确定分枝杆菌是否在结节病的免疫发病机制中起作用。我们将结合结节病和对照资源1)利用致病性分枝杆菌的基因对结节病肉芽肿进行分子表征，2)比较结节病患者与CBD患者、PPD对照人群和结核分枝杆菌感染患者的t细胞特异性干扰素-y产生。3)利用原位杂交技术在结节病物种中定位分枝杆菌，以便更好地了解宿主-病原体的相互作用。这些发现将以独立和互补的方式评估分枝杆菌在结节病免疫发病机制中的作用，可能对结节病的未来治疗方式产生影响。

DESCRIPTION (provided by applicant): Sarcoidosis is a disease of unknown etiology, characterized pathologically by noncaseating granulomas which most commonly involve the lung, skin, lymph node and eyes. Syndromes with similar pathologic and immunologic features to sarcoidosis such as chronic beryllium disease, hypersensitivity pneumonitis, and tuberculosis illustrate that granulomatous diseases may or may have an infectious etiology. We performed PCR analysis of paraffin-embedded sarcoidosis and control specimens for the presence of Mycobacterium 16S rRNA and rpoB. We found evidence of mycobacterial nucleic acids in 60% of the sarcoid granulomas and in none of the controls (p<0.00002, chi square). Sequence analysis of the 16S rRNA and rpoB amplicons revealed the presence of a novel Mycobacterium, genetically similar to M. tuberculosis (MTB) (99% positional identity). We expanded our work to include ten frozen sarcoidosis and ten control tissues from Vanderbilt University and from other regions of the United States. We identified mycobacterial nucleic acid in 50% of frozen sarcoidosis specimens and in none of controls (p<0.0325, two-tailed Fisher's test). Most recently, we performed ELISPOT assays on sarcoidosis (n=10) and control (n=9) peripheral blood mononuclear cells (PBMC). We found immune recognition of MTB katG peptides in 70.0% of the sarcoidosis specimens compared to none of the negative control specimens (p=0.01, ANOVA analysis). The central hypothesis is that sarcoidosis is an immunologic response to a mycobacterial infection in a genetically susceptible host. We have formed a national collaboration involving National Jewish Medical and Research Center, Vanderbilt University School of Medicine, and University of Colorado, Boulder. The purpose of the collaboration is to determine if mycobacteria have a role in sarcoidosis immunopathogenesis. We will combine the sarcoidosis and control resources 1) to perform molecular characterization of sarcoidosis granulomas using genes which speciate pathogenic mycobacteria, 2) to compare T-cell specific interferon-y production to mycobacterial peptides in sarcoidosis patients to CBD patients, a PPD- control population, and patients with M. tuberculosis infection, 3) to use in situ hybridization to localize mycobacteria within sarcoidosis species in order to better understand host-pathogen interactions. These findings, which will assess in an independent and complementary fashion the role of mycobacteria in sarcoidosis immunopathogenesis, may have an impact on future therapeutic modalities for sarcoidosis.