Clinical factors predictive of spontaneous remission or relapse in cases of autoimmune pancreatitis

BACKGROUND: The rates of spontaneous remission and relapse of autoimmune pancreatitis (AIP) are not known. OBJECTIVE: To study the clinicopathologic factors predictive of remission and relapse in cases of AIP. DESIGN: Retrospective study. PATIENTS: Of the 20 patients with AIP, complete response to steroid therapy was recognized in 12 patients, and the remaining 8 patients improved without steroid therapy. Seven patients experienced a relapse. RESULTS: Patients who were seronegative for immunoglobulin (Ig) G4, had no obstructive jaundice, no diabetes mellitus, no swelling of the duodenal papilla, negative staining of the duodenal papilla for IgG4, and focal pancreatic swelling showed a greater tendency toward spontaneous remission (P < .05). The results of multivariate analysis revealed that negative staining of the duodenal papilla for IgG4 was the only independent predictor of spontaneous remission of AIP (odds ratio [OR] 1.395, P = .0304). Seropositivity for IgG4, diffuse swelling of the pancreas, and the presence of stricture in the lower part of the bile duct were significantly associated with a relapse of AIP (P < .05) according to the results of univariate analysis, whereas the results of multivariate analysis revealed only diffuse pancreatic swelling as an independent predictor of a relapse of AIP (OR 26.197, P = .0331). CONCLUSIONS: Endoscopic findings are of useful prognostic value, because patients with AIP and with negative staining of the duodenal papilla for IgG4 appeared to have a higher frequency of remission without steroid therapy. Patients with AIP and with diffuse pancreatic swelling were found to be at an increased risk of relapse after the initial steroid administration.