[Studies of T-lymphocytes in pursuit of sarcoidosis antigens]

Sarcoidosis is characterised by lung accumulated activated T helper cells that are believed to be of central importance for the inflammatory reaction, which results in granuloma formation and in some patients in the development of fibrosis. It is generally considered that sarcoidosis is initiated and triggered by unknown antigen(s), resulting in disease in genetically predisposed individuals. Although a number of different micro-organisms as well as inorganic antigens have been suggested to cause the disease over the years, the exact aetiology of sarcoidosis is still unknown. In this article we describe how studies on T lymphocytes in sarcoidosis have gained insight into the pathogenesis of the disease. A remarkably strict correlation between lung accumulated T helper cells expressing a specific T cell receptor (AV2S3+) and HLA-DR17 was observed, indicating an immune attack against a specific target in the lungs. Future studies in this field may reveal how candidate antigens, identified by other techniques, play a role in the sarcoid inflammation.