| Theme |
Autoimmune Pancreatitis |
| Title |
Serological Markers for Autoimmune Pancreatitis |
| Author |
Shigeyuki Kawa |
Center for Health, Safety and Environmental Management, Shinshu University |
| Author |
Hideaki Hamano |
Department of Gastroenterology, Shinshu University School of Medicine |
| Author |
Tetsuya Ito |
Department of Gastroenterology, Shinshu University School of Medicine |
| Author |
Yayoi Ozaki |
Department of Gastroenterology, Shinshu University School of Medicine |
| Author |
Norikazu Arakura |
Department of Gastroenterology, Shinshu University School of Medicine |
| [ Summary ] |
Autoimmune pancreatitis exhibits various immunological abnormalities, and is thought to be caused by autoimmune mechanisms. It is frequently associated with obstructive jaundice at the onset of symptoms and must be differentiated from pancreatic cancer. Blood tests generally indicate abnormalities related to obstructive jaundice and immunoglobulin, as well as pancreatic endocrine and exocrine dysfunctions. Positive rates for gammaglobulin, IgG and IgG4 are 60, 70 and 90%, respectively. IgE is elevated in 30-40% of cases, indicating the contribution of allergies. Elevated HbA1c and decreased BT-PABA are found in tests over 50% of the time. Antinuclear antibody and rheumatoid factors are sometimes positive, ranging from 30 to 50%. However, disease specific antibodies, such as anti-SSA (Ro) or anti-SSB (La) antibodies or antimitochodorial antibodies are generally negative. Serum IgG4 is frequently elevated and is specifically, useful for the differentiation of autoimmune pancreatitis from pancreatic cancer, indicating higher sensitivity and a specificity of over 90%. It is also a sensitive marker for disease activity and a useful predictor of relapse. However, its role in pathogenesis is unclear. Complement C3 and C4 levels decrease to 30-40%, indicating that the complement activating system is a classical pathway in operation. These levels are also useful as disease activity markers. Other disease activity markers are immune complex and soluble IL2 receptors. |