Diagnostic Utility of Serum IgG4 in Autoimmune Pancreatitis

Abstract

Objectives: Despite many studies suggesting an association between serum immunoglobulin G4 (sIgG4) and autoimmune pancreatitis (AIP), the evidence of utility in differentiation between AIP and pancreatic cancer (PC) remain uncertain. Methods: The analysis based on published studies. Data were pooled by means of a random-effects model, and sensitivity, specificity, diagnostic odds ratios (DOR), areas under summary receiver operating characteristic curves were calculated. Results: In the included thirteen studies, sIgG4 were measured in 594 patients with AIP and 958 patients with PC. The pooled sensitivity, specificity, DOR, and area under the curve were 0.72 [95% confidence interval (CI): 0.68-0.75], 0.93 (95% CI: 0.92-0.95), 51.37 (95% CI: 23.20-113.74), and 0.91 (95% CI: 0.87-0.95). Subgroup analyses of the DORs for region and year: Asia, (112.10; 95% CI: 27.72-453.32), non-Asia (26.01; 95% CI: 12.38-54.65), and year before 2011 (107.61; 95% CI: 39.30-294.68), year after 2011 (26.96; 95% CI: 9.78-74.32). Overall, sIgG4 was associated with AIP, the result revealed a moderate sensitivity 0.72 and high specificity 0.93. In the meta-analysis, the pooled DOR of sIgG4 levels of 2-fold upper limit 50.44 was similar with the DOR 51.37 when 1-fold cut-off value, but the summary receiver operating characteristic was 0.755 and 0.91. The higher specificity (from 93% to 98%) derived from the cut-off value (from 130-140 to 260-280 mg/dL) for sIgG4 occurred at a significant reduction in sensitivity (from 72% to 43%). Conclusions: The study revealed sIgG4 is a good marker of AIP. Screening of sIgG4 may help clinicians differentiate between AIP and PC, and the best cut-off value should be 140 rather than 280 mg/dL.

Occam’s razor or Hickam’s dictum-COVID-19 is not a textbook aetiology of acute pancreatitis: A modified Naranjo Score appraisal

“…We additionally included questions on whether there is a cause-effect temporal relationship and a more in-depth approach in ruling out the other aetiologies of AP. This included ruling out autoimmune pancreatitis with testing for serum Immunoglobulin G4 (IgG4)[ 12 ], or whether an endoscopic ultrasound (EUS) or magnetic resonance cholangiopancreatography (MRCP) was performed to rule out occult microlithiasis, pancreatic malignancy or pancreatic divisum[ 13 ]. While genetic testing to rule out hereditary pancreatitis is a consideration[ 14 ], this was omitted in our modified Naranjo score as none of the included articles performed genetic tests for confirming/excluding hereditary pancreatitis.…”

The Significance of Serum IgG4/IgG and IgG4/IgG1 Ratio in the Diagnosis Value of IgG4-Related Diseases

“…The increase of serum IgG4 concentration is one of the important features and diagnostic criteria of IgG4-RD, but its sensitivity and specificity are unsatisfactory. Elevated serum IgG4 can occur in various non-IgG4-RD diseases, including diffuse connective tissue disease, chronic infection, leukemia, and allergic diseases, resulting in poor specificity and low positive predictive value [9]. A meta-analysis showed a pooled sensitivity of 87.2% and a specificity of 82.6% for serum IgG4.…”