Abstract IgG4-related disease (IgG4-RD) has been established in the 21st century as a novel systemic disease which is characterized by elevated levels of serum IgG4 and various lesion formation consisting of dense infiltration of IgG4-positive plasmacytes with fibrosis. The most common sites for IgG4-RD are the lacrimal glands, salivary glands, and pancreas. In addition, multiple organ involvement, including kidney, bile duct, and retroperitoneum, et al. form diverse clinical features in synchronous and metachronous course. Findings based on clinical observations from Japan has greatly contributed to the establishment of IgG4-RD. In the first place, Hamano et al. reported serum IgG4 concentrations as a biomarker to distinguish between autoimmune pancreatitis and pancreas cancer in 2001. Subsequently Yamamoto et al. revealed the difference between Mikulitz’s disease and Sjogren’s syndrome from elevated levels of serum IgG4 and histopathological findings in 2005, similar to autoimmune pancreatitis. It was finally proposed as IgG4-RD by the research group of the Japanese Ministry of Health, Labor and Welfare as a disease entity that includes those multiple organ involvements in 2010. Although the etiology and pathophysiology of IgG4-RD are still unknown, the roles of Tfh cells, Tph cells, and CD4-positive cytotoxic T cells, which have been recently attracting attention in various autoimmune diseases, has been recognized while the presence of autoantibodies have been reported. In addition to the etiology and pathophysiology, a lot of research results has being accumulated regarding classification criteria, diagnosis and treatment, as well as pathogenesis. Thus, in this session, Japanese specialists will provide commentary and the latest findings on each item of IgG4-RD (pathogenesis pathology, diagnosis, treatment, and topics, to raise awareness of IgG4-RD. We hope that the discussions conducted throughout this session will deepen mutual understanding regarding IgG4-RD.
Session Co-Chairs: Yoshiya Tanaka, MD, PhD Professor of the First Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health, Japan
Hiroki Takahashi, MD. PhD Professor of Department of Rheumatology and Clinical Immunology, School of Medicine, Sapporo Medical University
Overview Hiroki Takahashi, MD, PhD, Sapporo Medical University School of Medicine
New insights into the immunopathogenesis of IgG4-related disease Shingo Nakayamada, MD, PhD, University of Occupational and Environmental Health, Japan
Pathological features of IgG4-related disease Kenji Notohara, MD, PhD, Kurashiki Central Hospital
The diagnosis of IgG4-related disease Hajime Yoshifuji, MD, PhD, Kyoto University
Current and future treatments of IgG4-related disease Masatoshi Kanda, MD, PhD, Sapporo Medical University
New era of molecular targeted therapy for IgG4-related disease Hiroto Tsuboi, MD, PhD, University of Tsukuba
Closing Yoshiya Tanaka, MD, PhD, University of Occupational and Environmental Health
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