title: Diagnosis and Treatment of IgG4-Related Disease.
abstract: It is critical to differentiate IgG4-related disease (IgG4-RD) from malignant tumor and similar disease of the affected organ to apply appropriate therapy and avoid unnecessary surgery. IgG4-RD is diagnosed on combination of typical radiological findings; elevation of serum IgG4 levels; histopathological findings of abundant infiltration of IgG4-positive plasma cells and lymphocytes, storiform fibrosis , and obliterative phlebitis ; association with other IgG4-related diseases; and response to steroids. Histopathological approach is particularly recommended. Systemic glucocorticoids are currently the first-line approach for IgG4-RD, and the indications are symptoms. The initial recommended dose of oral prednisolone for induction of remission is 0.6 mg/kg/day, administered for 2-4 weeks. This dose is gradually tapered to a maintenance dose of 2.5-5 mg/day over a period of 2-3 months. As IgG4-RD sometimes relapses after steroids, maintenance therapy is usually performed in Japan. However, as IgG4-RD patients are typically elderly and are at high risk of developing steroid-related complications, cessation of the medication should be attempted at least within 3 years. For relapsed IgG4-RD, re-administration or dose up of steroid is effective, but the addition of immunomodulatory drugs such as azathioprine has been considered to be appropriate. B cell depletion with rituximab (an anti-CD20 antibody) is effective, even in many patients in whom treatment with immunomodulatory drugs was unsuccessful. The short-term clinical, morphological, and functional outcomes of most IgG4-RD patients treated with steroid therapy are good, but the long-term outcomes are less clear due to several unknown factors such as relapse, developed fibrosis, and associated malignancy.
authors.affiliation: Department of Internal Medicine, Tokyo Metropolitan Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-Ku, Tokyo, 113-8677, Japan. kamisawa@cick.jp.
authors.forename: Terumi
authors.initials: T
authors.lastname: Kamisawa
authors.affiliation: Department of Gastroenterology and Hepatology, Kansai Medical University, Osaka, Japan.
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Okazaki
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D007249:Inflammation / Q000175:diagnosis* / Q000188:drug therapy* / Q000276:immunology; D000069283:Rituximab / Q000008:administration & dosage
chemical_list: D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D000069283:Rituximab