[IgG4-RELATED DISEASE].

IgG4-related disease is a syndrome of unknown etiology, which can affect any organ. It is characterized by lymphoplasmacytic infiltration of the affected organs that is rich in IgG4-positive plasma cells, fibrosis, and sometimes increased blood levels of IgG4. Treatment is determined according to the organs involved and the severity of involvement. Corticosteroids are considered to be the first line of treatment. In steroid-resistant or recurrent disease, immunosuppressive drugs or rituximab are used, although their efficacy has not been proven in clinical trials. This review describes the current understanding of the pathogenesis, clinical features, diagnosis and treatment of IgG4-related disease.