Top ten list in sarcoidosis.

The increase in our knowledge of the immune mechanisms leading to the formation of the sarcoid granuloma unfortunately has not resolved the key question dealing with the etiologic agent(s) causing the disease. In this article, many genomes of Propionibacterium acnes or Propionibacterium granulosum were detected in specimens from 15 lymph node biopsies from 15 patients with sarcoidosis by using a quantitative polymerase chain reaction assay. The data suggest an etiologic link between propionibacteria and some cases of sarcoidosis. In particular, it is proposed that sarcoidosis may arise from a Th1 immune response to one or more antigens of propionibacteria in an individual with a hereditary or acquired abnormality of the immune system. Indeed, even if it is known that P acnes is a strong adjuvant, causing granulomas when injected experimentally into sensitized rats and rabbits, further experimental data are needed to draw definite conclusions about the pathogenetic role of propionibacteria in sarcoidosis. Pathogenesis