History of Autoimmune Pancreatitis and Mikulicz's Disease

The concept of a new class of systemic disease, IgG4-related disease, was established from findings in patients with autoimmune pancreatitis and Mikulicz's disease, showing the involvement of other organs. Autoimmune pancreatitis presents as a swollen pancreas that mimics pancreatic cancer and was first recognized by its characteristic findings of lymphoplasmacytic sclerosing pancreatitis (LPSP) and irregular narrowing of the main pancreatic duct. It was later found to be associated with autoimmunity and with high serum IgG4 concentrations and IgG4-bearing plasma cell infiltration. Autoimmune pancreatitis is also characterized by the systemic distribution of extra-pancreatic lesions and shows similar pathological findings of IgG4-bearing plasma cell infiltration, suggesting that autoimmune pancreatitis is a systemic, IgG4-related disease. Mikulicz's disease is another type of IgG4-related disease, presenting as symmetrical, painless enlargement of the lacrimal and salivary glands. Mikulicz's disease was considered as a complex of symptoms, rather than a disease entity. Furthermore, this disease had been regarded as one manifestation of a more generalized symptom complex known as Sjogren's syndrome. Mikulicz's disease was later distinguished from Sjogren's syndrome by its high serum IgG4 concentration and several characteristic clinical features. Mikulicz's disease shows similar systemic organ involvements as autoimmune pancreatitis. At present, autoimmune pancreatitis and Mikulicz's disease are recognized as major constituents of IgG4-relatated disease.