Long-Term Follow-Up and Immunomonitoring of Relapsing Type 1 Autoimmune Pancreatitis Treated With Rituximab

Objectives To evaluate the efficacy and safety of rituximab in relapsing type 1 autoimmune pancreatitis especially the long-term clinical and immunologic impacts. Methods All consecutive patients with type 1 autoimmune pancreatitis were retrospectively included. The rituximab protocol was induction therapy of 375 mg center dot m(-2) intravenous weekly for 4 weeks, followed by 500 mg intravenous every 6 months for 2 years. The follow-up included clinical examinations, biological tests, positron emission tomography scan, and immunomonitoring of lymphocyte CD 19+. Results Among the 43 patients included, 15 received rituximab induction therapy, followed by maintenance in 10 cases because of 1 or more relapses after steroids (whether or not followed by immunosuppressants) and multiple organ involvement. All patients had a clinical, biological and morphological response, a deep and persistent drop in serum immunoglobulin G4 levels, an extinction of both pancreatic and extra pancreatic hypermetabolic positron emission tomography scan signals, and a depletion of B lymphocyte CD19+. No relapse occurred during the follow-up (62.8 +/- standard error of the mean of 11.1 months). Conclusions Rituximab is an effective treatment for type 1 autoimmune pancreatitis that provides a rapid strong clinical, biological, and morphological response, which persists after discontinuation without any safety issues.