The immunopathogenesis of rheumatoid arthritis.

Rheumatoid arthritis is a chronic inflammatory disease of unknown aetiology. The immunohistology of the rheumatoid synovial membrane (which resembles classical cell-mediated immune lesions), the response to immunomodulatory therapies (thoracic duct drainage, lymphaphoresis, total lymphoid irradiation, anti-T cell monoclonal antibodies) and the strong association with HLA-DR4/DR1 all suggest that it is a disease whose pathogenesis is dependent on the T cell. This Workshop explores the relationship between the frequency of HLA-DR4/DR1 and the clinical expression of rheumatoid arthritis in Europe, where regional differences in these variables are known or suspected to exist.