Immunoglobulin G4-related diseases: Autoimmune pancreatitis and cholangitis.

Objective: Autoimmune pancreatitis (AIP) and cholangitis are chronic inflammatory diseases characterized by the infiltration of lymphoplasmocytic cells into the pancreas and biliary tract and fibrosis. This is often accompanied by increased serum immunoglobulin G4 (IgG4) levels. An early and accurate diagnosis is extremely important because they display similar features to other malignant diseases of the pancreas and biliary tract and primary sclerosing cholangitis. In this study, we aimed to convey our clinic's experiences on this topic.

Methods: The patients who were diagnosed with IgG4 (+)/(-) AIP and IgG4 (+) sclerosing cholangitis by excluding other causes with clinical, radiological, serological, and pathological examinations and treatment response between July 2014 and June 2020 were included in the study. The data of the patients were analyzed retrospectively.

Results: A total of 12 patients, 8 men and 4 women, were included in the study. The mean age of the patients was 39.4 (13-66) years. Abdominal pain of varying degrees was the main reason for admission in all patients. The time of diagnosis and follow-up was 19.2 (2-66) months on average. The average number of attacks during the follow-up was 2.9 (2-8) times. The average IgG4 level of the patients was calculated as 250.1 (133-409) mg/dL. All the patients were given 24-48 mg methylprednisolone at reduced doses for 6-8 weeks.

Conclusion: High serum IgG4 levels are the key indicators for diagnosis, and an early and accurate differential diagnosis is extremely important for malignant diseases of the pancreas and biliary tract. A good response to steroids is an important criterion for diagnosis as well as treatment.