Autoimmune pancreatitis (AIP) is part of a systemic fibro-inflammatory disease that can involve multiple organs which characteristically have a lymphoplasmacytic infiltrate rich in IgG4-positive cells. IgG4-related systemic disease (ISD) has been proposed by Kamisawa et al as the umbrella term to describe this multi-organ disease.1 Although the fibrosis in ISD can often lead to damage and even destruction of the involved organ, the inflammatory process typically responds to steroid treatment. However, the resolution of the inflammatory process in ISD may occur spontaneously without steroid treatment, especially in AIP.2 3 The effect of steroid treatment on the natural history of AIP is not known as it is only recently that large series of AIP are being reported.

In this issue of Gut (page 1719), Hirano et al4 report the results of a retrospective review of 42 AIP patients of whom 19 were treated with steroids. The authors’ goal was to determine the effect of steroids on subsequent disease relapse by comparing “unfavourable events” in steroid treated patients with those in historical controls presenting before 2003 who did not receive steroids. “Unfavourable events” included the development of obstructive jaundice related to distal biliary stricture, sclerosing cholangitis with elevated liver enzymes, growing pancreatic pseudocyst or other extra pancreatic lesions that required treatment (retroperitoneal fibrosis, interstitial nephritis, sialoadenitis). “Unfavourable events” were less in the steroid treated group compared to controls (32% vs 70%, p _ 0.01). The authors conclude that steroid treatment could reduce subsequent disease relapse and thus recommend the early introduction of steroids.

DEFINITIONS OF TREATMENT OUTCOMES

When discussing treatment in AIP, it is important to use specific terms that help identify treatment goals and responses. Remission refers to the resolution of disease-related symptoms and radiological abnormalities, whether spontaneously (spontaneous remission) or with steroids (steroid-induced remission), keeping in mind that in …