Propionibacterium aenesas a causative agent of sarcoidosis

结节病的病因不明，可能是由于遗传易感的受试者暴露于特定的环境因素，可能是传染性因素，尽管尚未确定。痤疮丙酸杆菌是迄今为止唯一从肉瘤病变中分离出来的细菌。用定量聚合酶链反应在结节淋巴结中检测到许多痤疮P的基因组。通过原位杂交，在肉芽肿内及周围的结节淋巴结中发现了P - acnes基因组。这些结果指出了P型痤疮和一些结节病病例之间的病原学联系。来自P痤疮的重组触发因子蛋白（RP35）在一些结节病患者中引起细胞免疫反应，但在没有结节病的受试者中没有。在一些用RP35蛋白和佐剂致敏的小鼠中，RP35引起肺颗粒瘤。痤疮P是最常见的原生性细菌外周肺组织和纵隔淋巴结，这可能是这些器官如此频繁涉及结节病的原因。在具有遗传或获得性免疫系统异常的个体中，肉瘤样肉芽肿可能是由于对一种或多种原生性或在受影响器官中增殖的痤疮假单胞杆菌抗原的Th1免疫应答而形成的。

Sarcoidosis, of unknown etiology, may result from exposure of a genetically susceptible subject to a specific enviromnental agent(s), possibly an infectious one, although none has been identified. Propionibacterium acnes is so far the only bacterium to be isolated from sarcoid lesions. Many genomes of P acnes have been detected in sarcoid lymph nodes by the quantitative polymerase chain reaction. By in situ hybridization, P acnes genomes were found in sarcoid lymph nodes in and around sarcoid granulomas. These results point to an etiological link between P acnes and some cases of sarcoidosis. A recombinant triggerfactor protein (RP35) from P acnes causes a cellular immune response in some patients with sarcoidosis, but not in subjects without sarcoidosis. RP35 causes pulmonary granuloinas in some of the mice sensitized with the protein and adjuvant. P acnes is the most common bacterium indigenous to the peripheral lung tissues and mediastinal lymph nodes, which may be the reason why these organs are so frequently involved in sarcoidosis. Sarcoid granulomas may be formed by a Th1 immune response to one or more antigens of P. acnes indigenous to or proliferating in the affected organs in an individual with a hereditary or acquired abnormality of the immune system.