Propionibacterium aenesas a causative agent of sarcoidosis

结节病，病因不明，可能是由于遗传易感受试者暴露于特定的环境因子（可能是感染性因子）所致，尽管尚未确定。痤疮丙酸杆菌是迄今为止从结节病病变中分离到的唯一细菌。用定量聚合酶链反应在结节病淋巴结中检测到许多痤疮丙酸杆菌的基因组。通过原位杂交，在结节病肉芽肿内及周围的结节病淋巴结中发现了痤疮丙酸杆菌基因组。这些结果表明痤疮丙酸杆菌和某些结节病病例之间存在病因学联系。来自痤疮丙酸杆菌的重组补体因子蛋白（RP 35）在某些结节病患者中引起细胞免疫应答，但在无结节病的受试者中不引起细胞免疫应答。RP35在用蛋白质和佐剂致敏的一些小鼠中引起肺颗粒细胞增多症。痤疮丙酸杆菌是周围肺组织和纵隔淋巴结最常见的细菌，这可能是结节病如此频繁地累及这些器官的原因。肉瘤样肉芽肿可以通过对一种或多种痤疮丙酸杆菌抗原的Th1免疫应答形成，所述痤疮丙酸杆菌抗原在具有遗传性或获得性免疫系统异常的个体的受影响器官中是固有的或在受影响器官中增殖。

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.