I g G 4‐related disease

Immunoglobulin G 4‐related disease ( I g G 4‐ RD ) is a regional or systemic fibro‐inflammatory disease of unknown etiology. It presents a distinctive histopathological appearance of dense lymphoplasmacytic infiltrates with abundant I g G 4‐positive plasma cells, storiform fibrosis and obliterative phlebitis with the appearance of inflammatory swelling or tumefactive lesions. This new disease entity includes a wide variety of diseases such as M ikulicz disease, autoimmune pancreatitis, R iedel thyroiditis, interstitial nephritis and retroperitoneal fibrosis. G lucocorticoid therapy can resolve the clinical and pathological abnormalities and impaired organ function. I g G 4‐ RD was recognized internationally in 2011, and new evidence has accumulated regarding its pathogenesis, clinical features and treatment. In this review, we outline our present understanding of I g G 4‐ RD .