Autoimmune pancreatitis (AIP) is a rare form of chronic pancreatitis. AIP is a relatively new disease entity, which has become a new evolving field in gastroenterology. Its importance and relevance are increasing, especially due to being one important differential diagnosis of pancreatic cancer.

Based on an international consensus, AIP is classified into two distinct types: (1) Type 1 AIP appears to be part of a systemic immunoglobulin IgG4-positive disease with lobular, interlobular inflammation, prominent lymphoplasmacytic inflammation and vasculitis, and intense fibrosis affecting multiple other organs (bile duct, kidney, salivary gland). (2) Type 2 AIP presents as a fibro-inflammatory duct-centric type with granulocyte epithelial pancreatic lesions and destruction of the pancreatic duct without IgG4-positive cells or systemic involvement.1

The only therapy that has been established and accepted so far is corticosteroids, but the relapse rate is significant (15%–60%).2 Limited data suggest that immune suppressive agents (like azathioprine) are recommended in patients who fail steroid therapy, exhibit relapse or cannot be weaned from steroids. A comparative study by Hart and colleagues3 tested immunomodulatory (IM) drugs, such as azathioprine, 6-mercaptopurine or mycophenolate mofetil for prevention of relapses in AIP. However, the authors concluded that relapse-free survival was similar in patients treated with steroids alone versus steroids plus IM maintenance treatment.

As the aetiology of AIP is still completely in the dark, development of clinically meaningful therapeutic approaches at least requires an understanding of the underlying disease pathophysiology. As suggested by its name, the immune …