What is Autoimmune Pancreatitis?

Sometimes the body’s immune system mistakenly attacks the pancreas, causing the organ to swell. This is known as autoimmune pancreatitis.

A rare disease, autoimmune pancreatitis is commonly confused with pancreatic cancer, as it often presents as a painless lump or mass on the pancreas. However, treatments for these diseases are very different. That’s why it is important to ensure an accurate diagnosis.

At UChicago Medicine, our experienced pancreatic disease team specializes in identifying and treating rare as well as common pancreatic diseases. Diagnosing autoimmune pancreatitis requires high-quality imaging and, in many cases, a biopsy. For that, our highly-skilled interventional gastroenterologists thread a thin tube (endoscope) through the mouth to the pancreas to take a sample of pancreatic tissue. Then our pathologists examine this tissue under a microscope. Modern laboratory approaches, including some special stains, are used to make it easier to see the hallmark cellular features of autoimmune pancreatitis.

Treatment for Autoimmune Pancreatitis

Autoimmune pancreatitis is typically treated with steroids and/or other drugs that weaken the body’s immune response (known as immunosuppressants or immunomodulators). The exact drug regimen needs to be customized to the patient, taking into account individual factors. For instance, some patients cannot be treated with steroids due to difficulty controlling blood sugar.

Autoimmune pancreatitis responds well to prescription medicine. But a significant number of patients experience repeat attacks of the disease. Reducing recurrences is important because uncontrolled autoimmune pancreatitis can lead to chronic pancreatitis and irreversible damage to pancreatic tissue.

The risk of recurrence depends, in part, on the type of autoimmune pancreatitis a patient has. There are two types:

  • Type 1 (IgG4-related) autoimmune pancreatitis tends to recur in more than 50 percent of patients. In addition to affecting the pancreas, type 1 autoimmune pancreatitis can inflame a patient’s liver, kidneys, thyroid, and other organs. Type 1 typically occurs in older people in their 60s and 70s, and is three times more common in men than women. Type 2 (idiopathic duct-centric) autoimmune pancreatitis only affects the pancreas. After being controlled by drugs, type 2 only recurs in about 10-20 percent of patients. Type 2 autoimmune pancreatitis is less common than Type 1, and typically develops in middle-aged women and men (with similar predisposition). Type 2 also tends to occur more in people with inflammatory bowel disease (i.e., Crohn disease and ulcerative colitis) as compared to Type 1
  • Treating autoimmune pancreatitis that recurs or does not respond well to medication can be medically challenging. The gastroenterologists at UC Medicine’s pancreas clinic have extensive experience managing this disease, including in patients with other complex health problems. They also stay on top of promising drug treatments, which means our patients are among the first to benefit from new therapies.

Frequently Asked Questions