Autoimmune pancreatitis (AIP) is the only pancreatic disorder responsive to steroid treatment. AIP has recently been subclassified into type 1 and type 2 AIP.1 Type 1 AIP is the pancreatic manifestation of immunoglobulin G4 (IgG4)-associated systemic disease (ISD), a fibroinflammatory autoimmune disorder that involves multiple organ systems and is characteristically associated with elevation of serum levels of IgG4.2 Commonly used diagnostic criteria for AIP include the Asian Consensus diagnostic criteria3 and the Mayo Clinic HISORt criteria4 (histology, imaging, serology, other organ involvement and response to corticosteroid treatment). Treatment protocols for AIP are still evolving, but corticosteroids are generally considered to be very effective in the initial inflammatory phase of the disease. Several small case series have reported that corticosteroids are effective in inducing remission in AIP, but larger series and controlled trials are lacking.

In this issue of Gut (see page 1504), Kamisawa and colleagues5 report results from a large, multicentre, retrospective survey of 563 patients with AIP treated at 17 referral centres in Japan. Their study highlights the fact that though a substantial proportion of patients with AIP may achieve spontaneous remission (77/104 patients, 74%), corticosteroids are also highly effective in inducing remission (451/459 patients, 98%). This study, despite the limitations of a retrospective and cross-sectional study design, provides the best evidence to date of the efficacy of corticosteroid treatment in the initial presentation of AIP. However, our knowledge of the natural history of AIP, predictors of relapse, need for maintenance treatment and the optimal type of maintenance treatment is still limited. The objective of this commentary is to provide a brief overview of the issues associated with corticosteroid treatment in AIP.