{"type":"root","children":[{"type":"paragraph","children":[{"type":"text","value":"IgG4 is one of four subtypes of IgG. IgG4-related sclerosing disease has been recognized as a systemic disease entity characterized by an elevated serum IgG4 level, sclerosing fibrosis and diffuse lymphoplasmacytic infiltration with the presence of many IgG4-positive plasma cells in affected tissues but also significantly higher IgG4/IgG ratios. Clinical manifestations are apparent in various organs such as pancreas, bile duct, gallbladder, lacrimal gland, salivary gland, retroperitoneum, kidney, lung, breast, thyroid, and prostate."}]}]}