IgG4-related disease (IgG4-RD) is a novel disease concept discovered in this century. IgG4-RD is systemic disorders characterized by increased serum IgG4 concentration and infiltration of IgG4-positive plasma cells in various organs, and includes various disorders which have been thought as different diseases so far, such as Mikulicz’s disease (IgG4-related sialoadenitis), autoimmune pancreatitis, retroperitoneal fibrosis, Küttner’s tumor, Riedel thyroiditis, etc.
Many Japanese researchers made important contribution for discovery of IgG4-RD and development of its disease concept. The first recognition between autoimmune pancreatitis and involvement of IgG4 was reported by Hamano et al. [Citation1]. And then, Mikulicz’s disease, which had been disappeared from the history of medicine, was also identified as an IgG4-related disorder by Yamamoto et al. [Citation2]. Later, many other diseases were classified in IgG4-RD. The consensus name of ‘IgG4-RD’ and development of a comprehensive diagnostic criteria for IgG4-RD have been dispatched from Japan to the world.
However, on the other hand, we need to pay attention sometimes to encounter cases with inadequate diagnosis and treatment if an immature understanding of IgG4-RD is spreading, often experienced in the dawn of novel disease proposal. Therefore, the development of useful classification criteria, rigid differential diagnosis and therapeutic guideline, as well as investigation of etio-pathogenesis, is necessary to avoid such misleading.
In these backgrounds, special issues of Modern Rheumatology for IgG4-RD were planned. In this issue and another issue, as a coordinate editor, I invited authors who have played a central role in the development of the concept and researches of IgG4-RD. These special issues of IgG4-RD contain the research upfront such as genetics, cytokines, immune cells, innate immunity and autoantibody, and also clinical topics including recent advance of classification criteria, autoimmune pancreatitis, sclerosing cholangitis, IgG4-related sialo/dacryoadenitis (Mikulicz’s disease), IgG4-related kidney disease, IgG4-related endocrine disease, IgG4-related lung disease, IgG4-related aortitis and retroperitoneal fibrosis.
True etiology and pathogenesis of IgG4-RD have still been unknown. But we hope its whole picture would be clarified in near future by the efforts of these researchers.
Conflict of interest
None.
References
- Hamano H, Kawa S, Horiuchi A, Unno H, Furuya N, Akamatsu T, et al. High serum IgG4 concentrations in patients with sclerosing pancreatitis. N Engl J Med. 2001;344(10):732–8.
- Yamamoto M, Ohara M, Suzuki C, Naishiro Y, Yamamoto H, Takahashi H, et al. Elevated IgG4 concentrations in serum of patients with Mikulicz’s disease. Scand J Rheumatol. 2004;33(6):432–3.