Chronic beryllium disease: a model for pulmonary sarcoidosis?

Chronic beryllium disease (CBD) and pulmonary sarcoidosis are two distinct chronic disorders, sharing the pathological lung hallmark of the non-caseating granuloma and the immunological feature of T cell activation at the site of disease. However, while CBD is a rare occupational disease in which the cause, i.e. the inhalation of beryllium, is well known since a long time, the etiology of sarcoidosis, which is far more common in the general population, is still unknown. Since granuloma formation requires the presence of an immunogenic initiating antigen, it has been hypothesized that sarcoidosis is an antigen-triggered (auto)immune disease. Furthermore, while the study of large populations exposed to beryllium did made possible the identification of distinct genetic susceptibility factors in CBD, only recently the role of some genetic polymorphisms in sarcoidosis has been unraveled. Therefore, it seems likely that the advancement in the understanding of the immuno-pathogenesis of CBD will also help to design focused genetic studies to finally identify the etiology of sarcoidosis. Moreover, it is also possible that some cases of sarcoidosis are instead been caused by the inhalation of beryllium in genetically susceptible individuals.