Clinical features and expressions of Foxp3 and IL-17 in type 1 autoimmune pancreatitis in China

Clinicopathological and immunological features of follicular pancreatitis - a distinct disease entity characterised by Th17 activation

AIM

Follicular pancreatitis is a recently recognised, distinct clinicopathological entity characterised by the presence of many intrapancreatic lymphoid follicles with reactive germinal centres. However, the clinicopathological and immunological features and causes have not yet been established. We assessed the clinicopathological and immunological profiles of patients with follicular pancreatitis who underwent surgery.

METHODS AND RESULTS

This study included three patients with pancreatic masses (age range = 62-75 years; women:men: 1:2). A histopathological study of the resected pancreatic masses revealed abundant lymphoid follicles with reactive germinal centres in both periductal regions and diffusely within the parenchyma. No storiform fibrosis, obliterative phlebitis or granulocytic epithelial lesions were observed. The immunohistochemical examination revealed an IgG4/IgG-positive plasma cell ratio <30% in all patients. Podoplanin (Th17 marker)-expressing lymphocytes were present in the lymphoid follicles of those with follicular pancreatitis, whereas these were absent in normal lymph nodes and in lymphoid follicles of those with IgG4-related autoimmune pancreatitis (AIP). An RNA digital counting assay clearly demonstrated that the expression counts of 20 genes, including dendritic cells and lymphoid follicles markers, and related cytokines were significantly higher in follicular pancreatitis than in IgG4-related AIP (P < 0.01). The expressions of CCR6 and IL23A, which are genes related to Th17, were high.

CONCLUSIONS

This study shows that follicular pancreatitis is a histopathologically and immunologically distinct disease entity of pancreatitis and is characterised by upregulated Th17 expression.

Identification of Novel Serum Autoantibodies for Differential Diagnosis of Autoimmune Pancreatitis and Pancreatic Ductal Adenocarcinoma

OBJECTIVES

The lack of specific biochemical markers is a major drawback for the diagnosis of autoimmune pancreatitis (AIP). The aims were to characterize the autoantibody profiles in AIP and pancreatic ductal adenocarcinoma (PDAC) and to identify circulating autoantibodies that could be diagnostic markers differentiating PDAC and the AIP subtypes.

METHODS

Tissue lysates obtained from the resected pancreas of patients with AIP and patients with PDAC were separated by 2-dimensional polyacrylamide gel electrophoresis subsequently immunoblotted with autologous sera. The immunoreactive spots were subjected to nanoscale liquid chromatography-electrospray ionization tandem mass spectrometry to identify serum autoantibodies to tissue-derived autoantigens associated with AIP and PDAC. Autoantibody concentrations for selected autoantigens were assessed by enzyme-linked immunosorbent assays.

RESULTS

A total of 115 immunoreactive spots were identified by 2-dimensional polyacrylamide gel electrophoresis/immunobloting. Nanoscale liquid chromatography-electrospray ionization tandem mass spectrometry-based analysis revealed 68 autoantigens in AIP, 26 in PDAC, and 21 present in both diseases. Assessment of 13 selected AIP autoantibody serum levels revealed that 7 of them had significantly higher titers in AIP versus PDAC. IgG-directed against transaldolase could significantly differentiate between the 2 AIP subtypes.

CONCLUSIONS

The novel panel of AIP autoantibodies is promising to supplement the predictive tests for AIP of the currently known autoantigens and represent a basis for a combined blood test to differentiate AIP from PDAC in the future.

Differential Diagnosis of Autoimmune Pancreatitis From Pancreatic Cancer by Analysis of Serum Gelatinase Levels

OBJECTIVES

The aim of this study was to analyze serum gelatinases as part of the clinical strategy for the preoperative differentiation between autoimmune pancreatitis (AIP) and pancreatic ductal adenocarcinoma (PDAC). The finding of differential markers will prevent unnecessary surgical resection and allow optimal treatment of these diseases.

METHODS

Quantitative gelatin zymography was applied to analyze all individual gelatinase forms in serum and to define proteinase alterations associated with AIP and PDAC. For this purpose, sera of 130 patients, being 29 with AIP, 33 with chronic pancreatitis, 32 with PDAC, and 36 healthy controls, were first assayed for gelatinase levels by quantitative zymography before further validation by the analysis with commercial sandwich enzyme linked immunosorbent assays.

RESULTS

Serum profiling data obtained by zymography analysis revealed that gelatinase B/matrix metalloproteinase 9 (MMP-9), the neutrophil gelatinase B-associated lipocalin/MMP-9 complex, and gelatinase A/MMP-2 levels were significantly increased in patients with AIP. These proteins are promising markers to discriminate between AIP and PDAC. The best composite parameter, being the ratio of total MMP-9 over MMP-2 levels, can predict 93% of the AIP and 75% of the PDAC correctly. With enzyme linked immunosorbent assay, we confirmed the zymography results.

CONCLUSIONS

Differential gelatinase serum profiles as AIP markers, together with other clinical tests, help to assure the diagnosis of PDAC or AIP.