Differentiation of autoimmune pancreatitis from pancreas cancer: utility of anti-amylase and anti-carbonic anhydrase II autoantibodies

Autoantibodies as Potential Liquid Biopsy Biomarker in Detection of Pancreatic Cancer: A Diagnostic Test Accuracy Review and Meta-Analysis

Autoantibodies against tumour-associated antigens (TAA) are promising biomarkers for cancer diagnosis. This systematic review aims to evaluate the diagnostic values of tumour-associated autoantibodies (TAAbs) in patients with pancreatic cancer. A search was conducted in the PubMed, Web of Science, and Embase databases to collect eligible studies. The primary outcomes included sensitivity, specificity, and accuracy of the test. We used QUADAS-2 to evaluate the risk of bias in the included studies. Meta-analysis was performed using MetaDisc 1.4 and STATA 14.0 software to calculate the combined sensitivity and specificity. A total of 49 articles were included in the final analysis that reported over 100 different TAAbs that were studied for the detection of pancreatic cancer. p53, Ezrin, CLDN17, KCNN3, SLAMF7, SLC22A11 and OR51F2 were the most frequently investigated autoantibodies in these studies. Ezrin exhibited better diagnostic performance with the pooled sensitivity, specificity and summary area under the receiver operating characteristic (SROC) curves being 56%, 88% and 0.90, respectively. Moreover, certain autoantibody combinations achieved substantially higher sensitivity at reasonably high levels of specificity. For example, the combination of Ezrin and ENOA1.2 autoantibodies with CA19.9 yielded sensitivity, specificity and area under the SROC curve of 100%, 92% and 0.96, respectively. TAAb is a promising diagnostic biomarker for early detection of PC, especially when combining TAAb with other markers. The promising candidate markers identified in this review deserve further validation in a broad screening population.

Recent advances in IgG4-related autoimmune pancreatitis

The incidence of IgG4-related autoimmune pancreatitis (IgG4-AIP) is high in Asia and other countries, and unnecessary treatment is often undertaken due to both missed diagnosis and misdiagnosis in clinical practice. Although IgG4-AIP has attracted increasing attention, the details of IgG4-AIP pathogenesis and systemic immune response, including its relationship to tumor pathogenesis, are still unclear. In recent years, research on serum immunological detection, pathological features, clinical manifestations, diagnosis and treatment measures for IgG4-AIP has gradually increased. It is of great importance to summarize and discuss the latest progress regarding IgG4-AIP disease.

Diagnostic Utility of Serum IgG4 in Autoimmune Pancreatitis: An Updated Comprehensive Systematic Review and Meta-analysis

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.

The Clinical Utility of Soluble Serum Biomarkers in Autoimmune Pancreatitis: A Systematic Review

Autoimmune pancreatitis (AIP) is a rare etiological type of chronic pancreatitis. The clinical and radiological presentation of AIP often resembles that of pancreatic cancer. Identifying non-invasive markers for their early distinction is of utmost importance to avoid unnecessary surgery or a delay in steroid therapy. Thus, this systematic review was conducted to revisit all current evidence on the clinical utility of different serum biomarkers in diagnosing AIP, distinguishing AIP from pancreatic cancer, and predicting disease course, steroid therapy response, and relapse. A systematic review was performed for articles published up to August 2021 by searching electronic databases such as MEDLINE, Web of Science, and EMBASE. Among 5123 identified records, 92 studies were included in the qualitative synthesis. Apart from immunoglobulin (Ig) G4, which was by far the most studied biomarker, we identified autoantibodies against the following: lactoferrin, carboanhydrase II, plasminogen-binding protein, amylase-α2A, cationic (PRSS1) and anionic (PRSS2) trypsinogens, pancreatic secretory trypsin inhibitor (PSTI/SPINK1), and type IV collagen. The identified novel autoantigens were laminin 511, annexin A11, HSP-10, and prohibitin. Other biomarkers included cytokines, decreased complement levels, circulating immune complexes, N-glycan profile changes, aberrant miRNAs expression, decreased IgA and IgM levels, increased IgE levels and/or peripheral eosinophil count, and changes in apolipoprotein isoforms levels. To our knowledge, this is the first systematic review that addresses biomarkers in AIP. Evolving research has recognized numerous biomarkers that could help elucidate the pathophysiological mechanisms of AIP, bringing us closer to AIP diagnosis and its preoperative distinction from pancreatic cancer.

Value of anti-plasminogen binding peptide, anti-carbonic anhydrase II, immunoglobulin G4, and other serological markers for the differentiation of autoimmune pancreatitis and pancreatic cancer

The diagnosis of autoimmune pancreatitis (AIP) and its differential diagnosis from pancreatic cancer (PC) can be challenging. In this retrospective study, we aimed to evaluate the value of anti-plasminogen binding peptide (a-PBP), immunoglobulin G4 (IgG4), and anti-carbonic anhydrase-II (a-CA-II), together with other serological markers whose value is not fully elucidated.The serum levels of a-PBP, IgG4, IgG, anti-nuclear antibodies (ANA), anti-lactoferrin (a-LF), a-CA-II, and rheumatoid factor (RF) were evaluated in patients with AIP (n = 29), PC (n = 17), pancreatic neuroendocrine neoplasm (P-NEN, n = 12), and alcoholic chronic pancreatitis (ACP, n = 41). ANCA were measured in the AIP patients.There was no statistically significant difference in mean a-PBP values in AIP compared with PC. A ROC curve showed that, when using a cut-off of 38.3 U, low values of a-PBP had a sensitivity and specificity of 45% and 71% for differentiating AIP from PC. The sensitivity and specificity of IgG4 (cut-off 1.4 g/L) for differentiating AIP from PC was 45% and 88%, but rose to 52% and 88% when using a cut-off of 1.09 g/L. When using this cut-off, the sensitivity and specificity for differentiating type 1 AIP from PC was 68% and 88%. None of the other markers were significantly changed in AIP versus PC. For differentiation of type 1 and type 2 AIP, the only significant differences were IgG4 in type 1 AIP (P < .01), with a sensitivity of 68% and a specificity of 80%, and c-ANCA elevations found in some type 2 AIP patients (P < .05).The only serological marker for which we found a statistically significant difference in mean values between AIP and PC was IgG4. However, the value of IgG4 for the distinction of AIP from PC was limited, probably in part due to the relatively high number of type 2 AIP patients in our study. In accord with recent publications, our data do not support a role of increased serum a-PBP for the diagnosis of AIP.

Serum Immunoglobulin G4 in Discriminating Autoimmune Pancreatitis From Pancreatic Cancer: A Diagnostic Meta-analysis

OBJECTIVE

Differentiation between autoimmune pancreatitis (AIP) and pancreatic cancer (PC) is a clinical challenge. Emerging published data on the accuracy of serum immunoglobulin G4 (IgG4) for the differential diagnosis between AIP and PC are inconsistent. The objective of our study was to perform a meta-analysis evaluating the clinical utility of serum IgG4 in the differential diagnosis between AIP and PC.

METHODS

We performed a systematic literature search of multiple electronic databases. The methodological quality of each study was assessed according to the Quality Assessment of Diagnostic Accuracy Studies checklist. Random-effects model was used to summarize the diagnostic odds ratio and other measures of accuracy.

RESULTS

Eleven studies comprising 523 AIP patients and 771 PC patients were included in the meta-analysis. The summary estimates for serum IgG4 in distinguishing AIP from PC were as follows: diagnostic odds ratio, 57.30 (95% confidence interval [CI], 23.17-141.67); sensitivity, 0.72 (95% CI, 0.68-0.76); specificity, 0.93 (95% CI, 0.91-0.94). The area under the curve of serum IgG4 in distinguishing AIP from PC was 0.9200.

CONCLUSIONS

Our meta-analysis found that serum IgG4 has high specificity and relatively low sensitivity in the differential diagnosis between AIP and PC. Therefore, serum IgG4 is useful in distinguishing AIP from PC.

Clinical usefulness of serum antibodies as biomarkers of gastrointestinal and liver diseases

The progressively growing knowledge of the pathophysiology of a number of immune-mediated gastrointestinal and liver disorders, including autoimmune atrophic gastritis, coeliac disease, autoimmune enteropathy, inflammatory bowel disease, autoimmune hepatitis, primary sclerosing cholangitis, primary biliary cholangitis and autoimmune pancreatitis, together with the improvement of their detection methods have increased the diagnostic power of serum antibodies. In some cases - coeliac disease and autoimmune atrophic gastritis - they have radically changed gastroenterologists' diagnostic ability, while in others - autoimmune hepatitis, inflammatory bowel disease and autoimmune pancreatitis - their diagnostic performance is still inadequate. Of note, serum antibody misuse in clinical practice has raised a number of controversies, which may generate confusion in the diagnostic management of the aforementioned disorders. In this review, we critically re-evaluate the usefulness of serum antibodies as biomarkers of immune-mediated gastrointestinal and liver disorders, and discuss their pitfalls and merits.

Diagnostic performance of serum IgG4 level for IgG4-related disease: a meta-analysis

An elevated serum IgG4 level is one of the most useful factors in the diagnosis of IgG4-related disease (IgG4-RD). In this study, we performed a meta-analysis of the published articles assessing the diagnostic accuracy of serum IgG4 concentrations for IgG4-RD. The databases of MEDLINE/PubMed, EMBASE and Web of Science were systematically searched for relevant studies. Sensitivities and specificities of serum IgG4 in each study were calculated, and the hierarchical summary receiver operating characteristic (HSROC) model with a random effects model were employed to obtain the individual and pooled estimates of sensitivities and specificities. In total, twenty-three studies comprising 6048 patients with IgG4-RD were included in the meta-analysis. The pooled sensitivity was 85% with a 95% confidence interval (CI) of 78-90%; the pooled specificity was 93% with a 95% CI of 90-95%. The HSROC curve for quantitative serum IgG4 lies closer to the upper left corner of the plot, and the area under the curve (AUC) was 0.95 (95% CI 0.93, 0.97), which suggested a high diagnostic accuracy of serum IgG4 for the entity of IgG4-RD. Our study suggests that serum IgG4 has high sensitivity and specificity in the diagnosis of IgG4-RD.

Serum IgG4 and IgG for the diagnosis of autoimmune pancreatitis: A systematic review with meta-analysis

BACKGROUND AND OBJECTIVE

The correct diagnosis of autoimmune pancreatitis (AIP) is a clinical challenge. Emerging published data on the accuracy of serum IgG4 and IgG for diagnosing AIP are inconsistent. This study was performed to better elucidate the accuracy of serum IgG4 and IgG in diagnosing AIP.

METHODS

A comprehensive literature search of PubMed, Web of Science, EMBASE, the Cochrane Library and some other databases was conducted before October 2014. The methodological quality of each study was assessed according to the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) checklist. Random-effects model was used to summarize the sensitivity, specificity and other measures of accuracy.

RESULTS

Fifteen studies on IgG4 and 8 studies on IgG were included. The summary estimates for serum IgG4 in distinguishing AIP from the overall controls, pancreatic cancer and ordinary chronic pancreatitis were as follows: sensitivity 0.74 (0.70-0.77), 0.73 (0.69-0.77) and 0.76 (0.72-0.80), respectively, specificity, 0.94 (0.93-0.95), 0.93 (0.91-0.95) and 0.96 (0.95-0.97), respectively. The summary estimates for serum IgG in distinguishing AIP from the overall controls and pancreatic cancer were as follows: sensitivity, 0.53 (0.47-0.59) and 0.51 (0.44-0.57), respectively, specificity, 0.87 (0.85-0.89) and 0.94 (0.91-0.96), respectively. The area under the curve (AUC) of serum IgG in distinguishing AIP from ordinary chronic pancreatitis was 0.657.

CONCLUSIONS

Both serum IgG4 and IgG have high specificity and relatively low sensitivity for diagnosing AIP. Besides, they are useful for distinguishing AIP from pancreatic cancer and ordinary chronic pancreatitis. To better elucidate the usefulness of serum IgG4 and IgG, further studies are needed.

Role of Amylase-α2A Autoantibodies in the Diagnosis of Autoimmune Pancreatitis

OBJECTIVES

Several serological markers have been reported in autoimmune pancreatitis (AIP) patients. However, only serum IgG4 (sIgG4) is available in clinical practice for AIP diagnosis. Antiamylase α antibodies (AMY-α Abs) have been proposed to diagnose AIP. This study evaluates the utility of AMY-α Abs and sIgG4 for AIP diagnosis.

METHODS

Twenty-five AIP patients, 84 disease control groups (31 chronic pancreatitis, 30 acute pancreatitis, 23 pancreatic adenocarcinoma), and 59 healthy donors were prospectively studied. The AMY-α Abs were determined by homemade enzyme-linked immunosorbent assay and sIgG4 by nephelometry.

RESULTS

Increased sIgG4 were detected to be present in 52% of AIP, 5% in control groups, and 0% in healthy donors, and AMY-α Abs, respectively, in 76%, 36%, and 2%. sIgG4 was elevated in 92% of the 13 patients with type 1 AIP, but in none of 3 with type 2 and of 8 with not otherwise specified AIP. The AMY-α Abs were present in 79%, 67%, and 75% of type 1, type 2, and not otherwise specified AIP, respectively. Sensitivity and specificity of AMY-α Abs were 76% and 78%, and of sIgG4 50% and 94%. By combining the 2 serological markers, sensitivity was 41%, and specificity was 99%.

CONCLUSIONS

The AMY-α Abs may help to diagnosis of AIP and to differentiate AIP subtypes.