Autoantibodies in Autoimmune Pancreatitis

Daniel S Smyk,Stephen Kriese,Eirini I Rigopoulou,Dimitrios P Bogdanos,Andreas L Koutsoumpas,Andrew K Burroughs

doi:10.1155/2012/940831

Abstract

Autoimmune pancreatitis (AIP) was first used to describe cases of pancreatitis with narrowing of the pancreatic duct, enlargement of the pancreas, hyper-γ-globulinaemia, and antinuclear antibody (ANA) positivity serologically. The main differential diagnosis, is pancreatic cancer, which can be ruled out through radiological, serological, and histological investigations. The targets of ANA in patients with autoimmune pancreatitis do not appear to be similar to those found in other rheumatological diseases, as dsDNA, SS-A, and SS-B are not frequently recognized by AIP-related ANA. Other disease-specific autoantibodies, such as, antimitochondrial, antineutrophil cytoplasmic antibodies or diabetes-specific autoantibodies are virtually absent. Further studies have focused on the identification of pancreas-specific autoantigens and reported significant reactivity to lactoferrin, carbonic anhydrase, pancreas secretory trypsin inhibitor, amylase-alpha, heat-shock protein, and plasminogen-binding protein. This paper discusses the findings of these investigations and their relevance to the diagnosis, management, and pathogenesis of autoimmune pancreatitis.

Highlights

Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis with raised levels of serum IgG4, responsiveness to immunosuppressive therapy, and no apparent underlying cause such as chronic alcoholic pancreatitis [1,2,3,4,5,6,7,8]
ELISA testing based on recombinant antigens revealed significantly increased levels at 1/600 serum dilution, against trypsinogen PRSS1 in AIP patients compared to non-AIP chronic pancreatitis patients or normal controls
It is possible that a loss of tolerance to a variety of pancreatic specific and nonpancreaticspecific antigens may be involved in the initiation of AIP

Summary

Introduction

Autoimmune pancreatitis (AIP) is a form of chronic pancreatitis with raised levels of serum IgG4, responsiveness to immunosuppressive therapy, and no apparent underlying cause such as chronic alcoholic pancreatitis [1,2,3,4,5,6,7,8]. The major differential diagnosis is pancreatic cancer, which is usually ruled out through radiological, serological, or histological investigation [22, 23]. Typical radiological features include diffuse pancreatic enlargement with a narrowed pancreatic duct [7, 29] These features, in the presence of a raised IgG4, are diagnostic of AIP [7, 29]. Features of autoimmune disease may be present and include the presence of a variety of autoantibodies and/or raised IgG [7, 29]. In addition to its role in the diagnosis of AIP, IgG4 appears to relate to the disease severity and clinical course. This paper describes the current data surrounding the presence and role of autoantibodies in AIP

Pathogenesis of AIP

Findings

Conclusion