Chapter 51 - Antipancreatic Autoantibodies

Abstract

Autoantibodies against exocrine pancreas, called pancreatic autoantibodies (PAB), are directed against glycoprotein 2 (GP2), the major zymogen granule membrane protein of pancreatic acinar cells, and presumably other minor components of acinar secretory storage granules of the pancreas such as the CUB and zona pellucida-like domain-containing protein 1 (CUZD1). PAB are routinely detected by indirect immunofluorescence (IIF) using frozen sections of unfixed human pancreas. Their antigen-specific testing is currently based on enzyme-linked immunosorbent assay (ELISA) using eukaryotically expressed recombinant GP2 and IIF based on GP2- and CUZD1-transfected HEK293 cells. PAB are strongly associated with the presence of inflammatory bowel disease (IBD) and in particular Crohn's disease (CD), being present in 29–44% of patients with CD but in less than 10% of ulcerative colitis (UC) patients. Excluding patients with UC and gluten-related disorder (GRD), the specificity of PAB for diagnosing CD is greater than 98%. More studies with assays using PAB-specific targets (GP2 and CUZD1) are necessary to evaluate the clinical and pathophysiological relevance of PAB further, as well as for further stratification of CD patients.