Identification of a Novel Autoantibody Against Pancreatic Secretory Trypsin Inhibitor in Patients with Autoimmune Pancreatitis

Abstract

These findings suggest that PSTI may be related to the pathogenesis of AIP, and autoantibodies against PSTI can be a useful diagnostic marker for the disease.

Autoimmune pancreatitis: current concepts

“…Other AIP-related antibodies have also been reported, such as anti-lactoferrin, anti-carbonic anhydrase-II/IV [28,29], anti-pancreatic secretory trypsin inhibitor [30], anti-amylasealpha [31], and anti-heat-shock protein-10 antibodies [32]. However, data about these auto-antibodies are not available in Caucasian patients, most of whom have type II AIP.…”

Autoimmune pancreatitis—a new evolving pancreatic disease?

“…Occasional coexistence of other organ involvement leads us to the concept that there may be common target antigens in the involved organs such as the pancreas, salivary gland, biliary tract, lung and renal tubules, and so on. Although the disease-specific antibodies have not been identified at this moment, several disease-related antibodies such as antilactoferrin (LF) [20,21], anti-carbonic anhydrase (CA)-II [20,21,54,55], anti-CA-IV [56], anti-pancreatic secretory trypsin inhibitor (PSTI) [22], anti-amylase-alpha [57], anti-HSP-10 [58], and anti-plasminogen-binding protein (PBP) peptide autoantibodies [59] have been reported. Although the patients show increased serum levels of IgG4, the major subclass of these autoantibody is not necessarily IgG4, but often IgG1 [22].…”

“…In pancreatic images, low-echoic swelling on US, sausage-like swelling with capsule-like rim and homogeneously delayed enhancement on CT, low-intensity on T1-weighted MR image, and diffuse narrowing of the main pancreatic duct on ERCP images are characteristic [5]. Increased serum levels of gammaglobulin, IgG, especially IgG4, IgG4 subclass of immune complexes, or autoantibodies such as ANF, ALF, ACA-II, and rheumatoid factor (RF) are useful for the diagnosis of AIP [4,5,21,22]. Among them, serum IgG4 is the best marker for diagnosing AIP at this moment, although it is not necessarily specific for it [7].…”

“…Moreover, several diagnostic criteria for AIP have been proposed from Japan [8,9], Korea [10,11], Asian consensus [12], Mayo clinic [13,14], and Verona [15,16]. However, pathogenesis still remains unclear, although some investigators have paid great attentions to the pathogenesis and pathophysiology AIP, especially in genetic analysis [17,18], IgG4 [19], diseaseassociated autoantibodies [20][21][22][23], complement system [24], and extrapancreatic lesions [4,5,[10][11][12][13][25][26][27][28][29][30][31].…”

Autoimmunpankreatitis–eine seltene und schwierige Differentialdiagnose zum Pankreaskarzinom

“…Inwiefern künftig weitere Seromarker wie beispielsweise der aktuell beschriebene PSTI-Antikörper ("pancreatic secretory trypsin inhibitor") [18] gestrebt werden, um das Fortschreiten eines als AIP fehldiagnostizierten Pankreaskarzinoms zur Inoperabilität zu vermeiden.…”