Presentation and Management of Post-treatment Relapse in Autoimmune Pancreatitis/Immunoglobulin G4-Associated Cholangitis

BACKGROUND & AIMS: Autoimmune pancreatitis (AIP) is a multisystem disorder that often has extrapancreatic manifestations such as immunoglobulin G4-associated cholangitis (IAC). Patients respond rapidly to steroids but can relapse after therapy. We assessed the clinical management of relapse in a group of patients with AIP/IAC. METHODS: We performed a prospective study of patients diagnosed with AIP from 2004-2007 who received steroids. Treatment outcome was defined clinically, radiologically, and biochemically as response to steroids, remission after steroids, failure to wean steroids, and relapse. Steroids +/- azathioprine (AZA) were used to treat patients who failed, relapsed, or could not be weaned from steroids. RESULTS: Twenty-eight patients with AIP were Studied; 23 (82%) had IAC. All patients responded within 6 weeks to prednisolone therapy. Twenty-three patients achieved remission after a median of 5 months of treatment (range, 1.5-17 months), whereas S patients (18%) could not be weaned because of a disease flare. Of the patients who achieved remission, 8 of 23 (35%) subsequently relapsed. Overall, 13 of 23 patients (57%) with AIP/IAC relapsed, compared with 0 of the 5 with isolated AIP (P = .04, Fisher exact test). Steroids were increased/restarted in all patients who relapsed; 10 also received AZA. Remission was achieved and maintained in 7 patients; they remain on AZA monotherapy at a median of 14 months (range, 1-27 months). CONCLUSIONS: Relapse or failure to wean steroids occurred in 46% of patients with AIP. Patients with IAC are at particularly high risk of relapse. AZA appears to be effective in patients with post-treatment relapse or who cannot be weaned from steroids.