The discovery of IgG4-associated diseases can be traced back to the study of autoimmune pancreatitis (AIP). Autoimmune pancreatitis was first proposed by Yoshida et al. in 1995, and the pathogenesis of the disease was suggested to be related to autoimmune factors. The relationship between AIP and IgG4-associated disease-positive plasma cells was first introduced and proposed in 2001, and AIP is often combined with similar lesions in other organs and tissues, such as salivary glands, bile ducts, and retroperitoneal tissues, and typical biopsy specimens from these organs and tissues (including AIP) show a large infiltration of IgG4-associated disease-positive lymphocytes. Thereafter, as research continued, Kamisawa et al. first introduced the concept of IgG4 systemic disease, IgG4-associated disease, also known as lgG4 multiorgan lymphoproliferative syndrome, in 2003, and the birth of this disease was announced in the journal AutoimmunRev in 2010.