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World J Gastroenterol. Feb 28, 2024; 30(8): 817-832
Published online Feb 28, 2024. doi: 10.3748/wjg.v30.i8.817
Autoimmune pancreatitis: Cornerstones and future perspectives
Camilla Gallo, Giulia Dispinzieri, Nicola Zucchini, Pietro Invernizzi, Sara Massironi
Camilla Gallo, Giulia Dispinzieri, Pietro Invernizzi, Sara Massironi, Division of Gastroenterology and Center for Autoimmune Liver Diseases, Department of Medicine and Surgery, Fondazione IRCCS San Gerardo dei Tintori; University of Milano-Bicocca, Monza 20900, Italy
Nicola Zucchini, Department of Pathology, Fondazione IRCCS San Gerardo dei Tintori, Monza 20900, Italy
Author contributions: Gallo C writing and supervising; Dispinzieri G writing; Zucchini N writing and figures editing; Massironi S coordinationg and supervising; Invernizzi P supervising.
Conflict-of-interest statement: Authors declare no conflict of interests for this article.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See:
Corresponding author: Sara Massironi, MD, PhD, Chief Physician, Doctor, Medical Assistant, Research Scientist, Division of Gastroenterology and Center for Autoimmune Liver Diseases, Department of Medicine and Surgery, Fondazione IRCCS San Gerardo dei Tintori; University of Milano-Bicocca, 33 Via Pergolesi, Monza 20900, Italy.
Received: November 15, 2023
Peer-review started: November 15, 2023
First decision: December 15, 2023
Revised: December 18, 2023
Accepted: January 25, 2024
Article in press: January 25, 2024
Published online: February 28, 2024

Autoimmune pancreatitis (AIP) is an autoimmune subtype of chronic pancreatitis resulting from the aberrant immune response against the pancreas, leading to inflammation and fibrosis. Although AIP is rare, its incidence is increasing and is often misdiagnosed as other pancreatic diseases. AIP is commonly classified into two types. Type 1 AIP (AIP-1) is typically associated with elevated serum immunoglobulin G4 (IgG4) levels and systemic manifestations, while type 2 AIP is typically a more localized form of the disease, and may coexist with other autoimmune disorders, especially inflammatory bowel diseases. Additionally, there is emerging recognition of a third type (type 3 AIP), which refers to immunotherapy-triggered AIP, although this classification is still gaining acceptance in medical literature. The clinical manifestations of AIP mainly include painless jaundice and weight loss. Elevated serum IgG4 levels are particularly characteristic of AIP-1. Diagnosis relies on a combination of clinical, laboratory, radiological, and histological findings, given the similarity of AIP symptoms to other pancreatic disorders. The mainstay of treatment for AIP is steroid therapy, which is effective in most cases. Severe cases might require additional imm-unosuppressive agents. This review aims to summarize the current knowledge of AIP, encompassing its epidemiology, etiology, clinical presentation, diagnosis, and treatment options. We also address the challenges and controversies in diagnosing and treating AIP, such as distinguishing it from pancreatic cancer and managing long-term treatment, highlighting the need for increased awareness and knowledge of this complex disease.

Keywords: Autoimmunity, Pancreatitis, Autoimmune pancreatitis, Immunoglobulin G4, Steroids, Relapse

Core Tip: Autoimmune pancreatitis (AIP) is rare and often misdiagnosed. The lymphoplasmacytic sclerosing form, type 1 AIP (AIP-1), represents the pancreatic manifestation of immunoglobulin G4-related disease, while the idiopathic ductal centric form, type 2 AIP (AIP-2), is often associated with inflammatory bowel disease. AIP-1 presents with obstructive jaundice or abnormalities in exocrine and endocrine pancreatic function; AIP-2 usually shows abdominal pain and acute pancreatitis. The atypical mass-forming abnormality of the pancreas implies the need to histologically distinguish AIP form pancreatic ductal adenocarcinoma. Steroids are the first-line therapy for both AIP-1 and AIP-2, rituximab is a good alternative for AIP-1. Given the high relapse rate, long-term maintenance therapy is recommended. Scientific efforts are focusing on target therapies.