The clinical utility of immunoglobulin G4 in the evaluation of autoimmune pancreatitis and pancreatic adenocarcinoma Journal Article

Authors: Pak, L. M.; Schattner, M. A.; Balachandran, V.; D'Angelica, M. I.; DeMatteo, R. P.; Kingham, T. P.; Jarnagin, W. R.; Allen, P. J.
Article Title: The clinical utility of immunoglobulin G4 in the evaluation of autoimmune pancreatitis and pancreatic adenocarcinoma
Abstract: Background: Elevation in the serum immunoglobulin-G4 (IgG4) level has been used as a diagnostic marker to distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC), but its true utility is ill-defined. This study evaluates the clinical utility of IgG4 in differentiating AIP from PDAC. Methods: All patients evaluated in the hepatopancreaticobiliary surgery clinics with measured serum IgG4 were included. Patients were divided into normal IgG4 (<135 mg/dL) and elevated IgG4 (≥135 mg/dL) groups. The final diagnosis was determined by operative pathology when available or by clinical outcome. The sensitivity, specificity, PPV, and NPV of IgG4 for diagnosing AIP was assessed. Results: Between 1997 and 2015, 298 patients were identified. Normal IgG4 levels were present in 85% of patients (254/298), while 15% (44/298) were elevated. The overall prevalence of AIP was 17% (52/298). The sensitivity and specificity of IgG4 for AIP was 67% and 96%, respectively; however, the PPV was only 80%, including a 9% occurrence of PDAC in patients with an elevated IgG4. Conclusion: In this study of selected patients who underwent IgG4 testing, 9% of elevated IgG4 patients had PDAC. The overreliance on IgG4 as diagnostic for AIP may lead to mis-diagnosis and delayed treatment for PDAC. © 2017 International Hepato-Pancreato-Biliary Association Inc.
Keywords: adult; human tissue; aged; major clinical study; outcome assessment; sensitivity and specificity; prevalence; diagnostic value; pancreas adenocarcinoma; immunoglobulin blood level; pancreas biopsy; predictive value; immunoglobulin g4; autoimmune pancreatitis; diagnostic test accuracy study; very elderly; human; male; female; article
Journal Title: HPB
Volume: 20
Issue: 2
ISSN: 1365-182X
Publisher: Elsevier Science, Inc.  
Date Published: 2018-02-01
Start Page: 182
End Page: 187
Language: English
DOI: 10.1016/j.hpb.2017.09.001
PROVIDER: scopus
PUBMED: 29033025
Notes: Article -- Export Date: 1 March 2018 -- Source: Scopus
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MSK Authors
  1. Ronald P DeMatteo
    597 DeMatteo
  2. Peter Allen
    436 Allen
  3. William R Jarnagin
    583 Jarnagin
  4. T Peter Kingham
    281 Kingham
  5. Mark Schattner
    102 Schattner
  6. Linda Ma
    16 Ma