IgG4-related disease of the biliary tract and pancreas: clinical and experimental advancesHubers, Lowiek M.; Beuers, UlrichCurrent Opinion in Gastroenterology: July 2017 - Volume 33 - Issue 4 - p 310–314 doi: 10.1097/MOG.0000000000000362 Special Commentary Abstract Author Information Purpose of review IgG4-related disease (IgG4-RD) is an immune-mediated disease of unknown cause. It predominantly affects the biliary tract [IgG4-associated cholangitis (IAC)] and pancreas [autoimmune pancreatitis (AIP)] of mostly elderly men. Accurate diagnostic tests are lacking. Patients benefit from predniso(lo)ne treatment. However, disease relapse is often seen. This review will address pathophysiological aspects and advances in diagnostic and therapeutic strategies. Recent findings The role of IgG1 and IgG4 in the pathophysiology of IgG4-RD was studied in mice which showed more intense organ damage of pancreas and salivary glands when IgG1 rather than IgG4 of patients with IgG4-RD was injected. Coadministration of IgG1+IgG4 led to dampening of IgG1-mediated injury supporting the view that IgG4 exerts immune-dampening effects. IgG4+ B-cell receptor clones identified by next-generation sequencing and the IgG4/IgG RNA ratio in human blood assessed by quantitative PCR were able to accurately distinguish IAC/AIP from primary sclerosing cholangitis or pancreatobiliary malignancies. Long-term treatment with low-dose prednisolone was safe and reduced the number of flare-ups in patients with AIP. Summary Early diagnosis by a novel accurate and easy-to-use qPCR test may prevent life-threatening complications, unnecessary interventions and fatal course because of misdiagnosis. Prednisolone treatment remains the standard of care in patients with IgG4-RD. Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Centre, Amsterdam, The Netherlands Correspondence to Ulrich Beuers, MD, Department of Gastroenterology and Hepatology, Tytgat Institute for Liver and Intestinal Research, Academic Medical Centre, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. Tel: +31 20 566 2422; e-mail: email@example.com Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.