IgG4 immunostaining of duodenal papillary biopsy specimens may be useful for supporting a diagnosis of autoimmune pancreatitis

IgG4-related cholangitis - a mimicker of fibrosing and malignant cholangiopathies

IgG4-related cholangitis (IRC) is the major hepatobiliary manifestation of IgG4-related disease (IgG4-RD), a systemic fibroinflammatory disorder. The pathogenesis of IgG4-RD and IRC is currently viewed as multifactorial, as there is evidence of a genetic predisposition while environmental factors, such as blue-collar work, are major risk factors. Various autoantigens have been described in IgG4-RD, including annexin A11 and laminin 511-E8, proteins which may exert a partially protective function in cholangiocytes by enhancing secretion and barrier function, respectively. For the other recently described autoantigens, galectin-3 and prohibitin 1, a distinct role in cholangiocytes appears less apparent. In relation to these autoantigens, oligoclonal expansions of IgG4+ plasmablasts are present in patients with IRC and disappear upon successful treatment. More recently, specific T-cell subtypes including regulatory T cells, follicular T helper 2 cells, peripheral T helper cells and cytotoxic CD8+ and CD4+ SLAMF7+ T cells have been implicated in the pathogenesis of IgG4-RD. The clinical presentation of IRC often mimics other biliary diseases such as primary sclerosing cholangitis or cholangiocarcinoma, which may lead to inappropriate medical and potentially invalidating surgical interventions. As specific biomarkers are lacking, diagnosis is made according to the HISORt criteria comprising histopathology, imaging, serology, other organ manifestations and response to therapy. Treatment of IRC aims to prevent or alleviate organ damage and to improve symptoms and consists of (i) remission induction, (ii) remission maintenance and (iii) long-term management. Glucocorticosteroids are highly effective for remission induction, after which immunomodulators can be introduced for maintenance of remission as glucocorticosteroid-sparing alternatives. Increased insight into the pathogenesis of IRC will lead to improved diagnosis and novel therapeutic strategies in the future.

Autoimmune Pancreatitis and Immunoglobulin G4-related Sclerosing Cholangitis: Past, Present, and Future

The emergence of glucocorticoid-responsive autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis (IgG4-SC), a new disease entity, has attracted considerable interest within the international gastroenterology community. The typical manifestations of AIP/IgG4-SC are obstructive jaundice and pancreatic enlargement in the elderly, which may mimic the presentations of pancreatobiliary malignancies. The timely diagnosis of AIP/IgG4-SC can lead to adequate glucocorticoid treatment, whereas a misdiagnosis can result in unnecessary major surgery. The diagnostic criteria used to diagnose AIP include several cardinal features of AIP that can be detected via pancreatic parenchymal imaging, ductal imaging, serum IgG4 levels, histopathology, other organ involvement, and response to glucocorticoid therapy. The differential diagnosis of AIP/IgG4-SC may include pancreatobiliary malignancies and primary sclerosing cholangitis. Although most patients with AIP/IgG4-SC respond well to glucocorticoid therapy, there is a frequent relapse of the disease in the long term. This review describes the evolution of the concept of AIP and IgG4-related disease, including the development of diagnostic criteria, discusses the current practice for diagnosis and treatment, and suggests prospects for research.

The value of endoscopic ultrasonography for differential diagnosis in obstructive jaundice of the distal common bile duct

INTRODUCTION

Obstructive jaundice is a common clinical disease of great significance; however, diagnosing it according to etiology, especially in patients with distal obstructive jaundice is difficult. The development of endoscopic ultrasonography has improved diagnostic methods. Endoscopic ultrasonography not only improves the accuracy of conventional endoscopic ultrasound technology in etiological diagnosis, but also offers several special endoscopic ultrasound technologies for diagnosing distal obstructive jaundice of the common bile duct. What's more, endoscopic ultrasonography can be used to treat distal obstructive jaundice of common bile duct.

AREAS COVERED

This review discusses the diagnostic value and applications of endoscopic ultrasonography for obstructive jaundice of the distal common bile duct.

EXPERT OPINION

This article summarizes the value of endoscopic ultrasonography in the etiological diagnosis, relevant treatment applications of distal obstructive jaundice and the limitations of endoscopic ultrasonography in some etiologies due to the lack of clear comparison with other imaging methods. We also provide new data for the future research direction of endoscopic ultrasonography in distal obstructive jaundice.

Autoimmune pancreatitis: What we know so far

Autoimmune pancreatitis (AIP) is a rare, often‐missed disease that involves inflammation of the pancreas and strictures of the pancreatic duct. Its prevalence and incidence in the United States remain scarce. The disease has a varied presentation and often mimics pancreatic malignancy, which can make the diagnosis challenging. Most patients have an excellent response to corticosteroid therapy. Immunomodulators may be used in some cases. Rituximab is an effective, emerging treatment in steroid‐refractory cases. This study aims to review the two distinct types of AIP and provide a detailed analysis of the diagnostic approach and treatment modalities.

Clinical characteristics of immunoglobulin IgG4-related sclerosing cholangitis: Comparison of cases with and without autoimmune pancreatitis in a large cohort

BACKGROUND

The clinical characteristics of IgG4-related sclerosing cholangitis (IgG4-SC) especially without autoimmune pancreatitis (AIP) have not been investigated in a large cohort.

AIMS

To clarify the clinical characteristics of IgG4-SC and IgG4-SC without AIP.

METHODS

We retrospectively reviewed imaging, serology, other organ involvement (OOI) and histology of 872 patients with IgG4-SC who participated in a Japanese nationwide survey in 2019, and compared these items between IgG4-SC with and without AIP.

RESULTS

AIP was present in 83.7% (730/872) of IgG4-SC. In IgG4-SC, bile duct wall thickening was observed on ultrasound (528/650; 81.2%), computed tomography (375/525; 71.4%) and magnetic resonance imaging or cholangiopancreatography (290/440; 65.9%). An elevated serum IgG4 level (≥ 135 mg/dL) was found in 88.0% (322/366). IgG4-related OOI other than AIP was observed in 25.2% (211/836). The proportion of females was significantly higher in IgG4-SC without AIP (28.9% vs. 20.1%; p = 0.025). Hilar stricture was the most common cholangiographic type in IgG4-SC without AIP (39/107; 36.4%).There were no significant differences between IgG4-SC with and without AIP in the rates of bile duct wall thickening, elevated serum IgG4 level, or IgG4-related OOI.

CONCLUSIONS

The clinical characteristics of IgG4-SC was similar between IgG4-SC with and without AIP in a large cohort.

Classification and Diagnostic Criteria for IgG4-Related Sclerosing Cholangitis

IgG4-related sclerosing cholangitis (IgG4-SC) can be classified into four types based on cholangiographic findings and regions of biliary stricture. This cholangiographic classification is useful to differentiate IgG4-SC from mimickers including cholangiocarcinoma, primary sclerosing cholangitis, and pancreatic cancer. Autoimmune pancreatitis (AIP) is a valuable clue for the diagnosis of IgG4-SC because the two are frequently found in association with each other. Two sets of diagnostic criteria for IgG4-SC have been proposed. In Japan, the clinical diagnostic criteria 2020 were recently developed. These clinical diagnostic criteria include narrowing of the intrahepatic and/or extrahepatic bile duct, thickening of the bile duct wall, serological findings, pathological findings, other organ involvement, and effectiveness of steroid therapy. When these criteria are applied, IgG4-SC is initially classified as associated or not associated with AIP, and cholangiographic classification is used for differential diagnosis. In most instances, IgG4-SC can be diagnosed on the basis of clinical diagnostic criteria. However, it is challenging to diagnose isolated IgG4-SC or IgG4-SC not associated with AIP. Here, we review the classification and diagnostic criteria for IgG4-SC, specifically focusing on the clinical diagnostic criteria 2020 and a large IgG4-SC case series from a nationwide survey in Japan.

Endoscopic retrograde cholangiopancreatography and intraductal ultrasonography in the diagnosis of autoimmune pancreatitis and IgG4-related sclerosing cholangitis

Endoscopic retrograde cholangiopancreatography is used to evaluate the narrowing of the main pancreatic duct in autoimmune pancreatitis (AIP) and biliary stricture in IgG4-related sclerosing cholangitis (IgG4-SC). Intraductal ultrasonography enables detailed visualization of the thickening of the bile duct wall in IgG4-SC. Pancreatic cancer, cholangiocarcinoma, and primary sclerosing cholangitis are important mimicking conditions of AIP and IgG4-SC. Diffuse or segmental stricture without marked upstream dilatation is a typical pancreatographic finding in AIP. By contrast, a single, short stricture with marked upstream dilatation is a typical finding in pancreatic cancer. The cholangiogram of IgG4-SC is classified into four types based on biliary stricture location, and this cholangiogram classification is useful for the differential diagnosis of IgG4-SC. Endoscopic retrograde cholangiography can be used to distinguish between IgG4-SC and primary sclerosing cholangitis. A segmental/long and intrapancreatic stricture is a characteristic finding of IgG4-SC, whereas band-like strictures, a beaded or pruned-tree appearance, and diverticulum-like outpouching are characteristic of primary sclerosing cholangitis. The characteristic intraductal ultrasonographic findings of circular-symmetrical wall thickening, smooth outer and inner margins, and homogeneous internal echo at the biliary stricture site are useful for diagnosis of IgG4-SC. Thickening of the bile duct wall at non-stricture sites is also a typical intraductal ultrasonographic finding of IgG4-SC and can be used for differential diagnosis from cholangiocarcinoma. Transpapillary bile duct and duodenal papilla biopsy during endoscopic retrograde cholangiopancreatography are also useful in the diagnosis of IgG4-SC.

Role of Endoscopic Procedures in the Diagnosis of IgG4-Related Pancreatobiliary Disease

The emergence of the disease entity of glucocorticoid-responsive systemic immunoglobulin G4 (IgG4)-related pancreatobiliary disease has generated substantial attention among the international gastroenterology society. IgG4-related pancreatobiliary disease includes type 1 autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis (IgG4-SC). The typical manifestations of IgG4-related pancreatobiliary disease are cholestatic liver dysfunction, obstructive jaundice, and weight loss, although it may present with no clinical symptoms. Since it mimics tumors on imaging, AIP/IgG4-SC may often be misdiagnosed as pancreatic or biliary cancer. The endoscopic armamentarium for the diagnosis of IgG4-related pancreatobiliary disease includes endoscopic ultrasonography, intraductal ultrasonography, endoscopic retrograde cholangiopancreatography, and cholangioscopy. The role of endoscopic tissue acquisition is two-fold in the diagnosis of IgG4-related pancreatobiliary disease: exclusion of cancer and procurement of histopathological proof for diagnosis of AIP/IgG4-SC, which can also be achieved by adding the immunohistochemistry for IgG4. Our review article addresses the role of various endoscopic examinations in diagnosing IgG4-related pancreatobiliary disease, focusing on the differentiation of this condition from pancreatobiliary malingnancies.

IgG4-related sclerosing cholangitis- A great mimicker

IgG4-related disease (IgG4 RD) is a multisystem disorder characterized by tumefactive (mass forming) lesions, storiform fibrosis, and IgG4-positive plasma cell infiltration. IgG4 sclerosing cholangitis (IgG4 SC) is the biliary manifestation of IgG4 RD, often in association with autoimmune pancreatitis (AIP). Here, we report two patients with IgG4-related cholangitis mimicking primary sclerosing cholangitis.

The use of immunohistochemistry for IgG4 in the diagnosis of autoimmune pancreatitis: A systematic review and meta-analysis

BACKGROUND

The diagnosis of autoimmune pancreatitis (AIP) remains challenging, especially when serum IgG4 is normal or imaging features are indeterminate. We performed a systematic review and meta-analysis to evaluate the performance of IgG4 immunostaining of pancreatic, biliary, and ampullary tissues as a diagnostic aid for AIP.

METHODS

A comprehensive literature search of the PubMed, EMBASE, and Ovid MEDLINE databases was conducted until February 2020. The methodological quality of each study was assessed according to the Quality Assessment of Diagnostic Accuracy Studies checklist. A random-effects model was used to summarize the diagnostic odds ratio and other measures of accuracy.

RESULTS

The meta-analysis included 20 studies comprising 346 patients with AIP and 590 patients with other pancreatobiliary diseases, including 371 pancreatobiliary malignancies. The summary estimates for tissue IgG4 in discriminating AIP and controls were as follows: diagnostic odds ratio 38.86 (95% confidence interval (CI), 18.70-80.75); sensitivity 0.64 (95% CI, 0.59-0.69); specificity 0.93 (95% CI, 0.91-0.95). The area under the curve was 0.939 for tissue IgG4 in discriminating AIP and controls. Subgroup analysis revealed no significant difference in diagnostic accuracy according to control groups (pancreatobiliary cancer versus other chronic pancreatitis) and sampling site (pancreas versus bile duct/ampulla).

CONCLUSIONS

Current data demonstrate that IgG4 immunostaining of pancreatic, biliary, and ampullary tissue has a high specificity but moderate sensitivity for diagnosing AIP. IgG4 immunostaining may be useful in supporting a diagnosis of AIP when AIP is clinically suspected, but a combination of imaging and serology does not provide a conclusive diagnosis.

The Diagnosis of Autoimmune Pancreatitis Using Endoscopic Ultrasonography

Autoimmune pancreatitis (AIP) is characterized by enlargement of the pancreas and irregular narrowing of the main pancreatic duct. It is often associated with IgG4-related sclerosing cholangitis (IgG4-SC), in which the bile duct narrows. Although characteristic irregular narrowing of the pancreatic duct caused by endoscopic retrograde cholangiopancreatography is noted in AIP, it is difficult to differentiate between localized AIP and pancreatic carcinoma based on imaging of the pancreatic duct. While stenosis of the bile duct in IgG4-SC is characterized by longer-length stenosis than in cholangiocarcinoma, differentiation based on bile duct imaging alone is challenging. Endoscopic ultrasound (EUS) can characterize hypoechoic enlargement of the pancreas or bile duct wall thickening in AIP and IgG4-SC, and diagnosis using elastography and contrast-enhanced EUS are being evaluated. The utility of EUS-guided fine needle aspiration for the histological diagnosis of AIP has been reported and is expected to improve diagnostic performance for AIP. Findings in the bile duct wall from endoscopic retrograde cholangiopancreatography followed by intraductal ultrasonography are useful in differentiating IgG4-SC from cholangiocarcinoma. Diagnoses based on endoscopic ultrasonography play a central role in the diagnosis of AIP.

Idiopathic recurrent acute pancreatitis

Idiopathic recurrent acute pancreatitis is clinically challenging and has substantial socioeconomic consequences. Investigations are expensive and often reveal little about the cause of the disease. Little is known about the interaction between genetic, environmental, anatomical, and other factors that contribute to the disease. Data on the efficacy, safety, and long-term outcomes of endoscopic therapies are scarce. The effect of idiopathic recurrent pancreatitis on quality of life is often underestimated. A more thorough examination of the causes of the disease and the roles of other associated risk factors is needed, as are well designed clinical studies with robust and objectively measurable outcomes. Ideally, evaluation of the causes of disease and therapy should be done only in specialised centres, should follow a protocol, and all outcomes should be formally assessed.

IgG4-related disease: with emphasis on the biopsy diagnosis of autoimmune pancreatitis and sclerosing cholangitis

In 2011, chronic fibroinflammatory processes occurring simultaneously or metachronously in various organs and associated with elevated IgG4 serum levels and/or tissue infiltration with IgG4-positive plasma cells have been recognized as manifestations of a systemic disorder called IgG4-related disease (IgG4-RD). The histologic key findings are lymphoplasmacytic infiltration rich in IgG4-positive plasma cells combined with storiform fibrosis and obliterative phlebitis. Among the organs mainly affected by IgG4-RD are the pancreas and the extrahepatic bile ducts. The pancreatic and biliary alterations have been described under the terms autoimmune pancreatitis (AIP) and sclerosing cholangitis, respectively. These diseases are currently more precisely called IgG4-related pancreatitis (or type 1 AIP to distinguish it from type 2 AIP that is unrelated to IgG4-RD) and IgG4-related sclerosing cholangitis (IgG4-related SC). Clinically and grossly, both diseases commonly imitate pancreatic and biliary adenocarcinoma, tumors that are well known for their dismal prognosis. As IgG4-RD responds to steroid treatment, making a resection of a suspected tumor unnecessary, a biopsy is often required to establish the preoperative diagnosis. This review discusses the morphologic spectrum of IgG4-related pancreatitis and IgG4-related SC and focuses on the biopsy relevant histologic features for the diagnosis and differential diagnosis of these diseases.

IgG4-related Disease and the Liver

Pathologists are likely to encounter IgG4-related disease in several organ systems. This article focuses on helping pathologists diagnose IgG4-related disease in the hepatobiliary system. Missing the diagnosis can result in unnecessary organ damage and/or unnecessary surgical and cancer therapy. In the liver, tumefactive lesion(s) involving the bile ducts with storiform fibrosis and an IgG4-enriched lymphoplasmacytic infiltrate are highly concerning for IgG4-related disease. The recent identification of oligoclonal populations of T cells and B cells in IgG4-related disease may lead to molecular tests, new therapeutics, and a greater mechanistic understanding of the disease.

IgG4-related hepatobiliary disease: an overview

IgG4-related hepatobiliary diseases are part of a multiorgan fibroinflammatory condition termed IgG4-related disease, and include IgG4-related sclerosing cholangitis (IgG4-SC) and IgG4-related hepatopathy. These diseases can present with biliary strictures and/or mass lesions, making them difficult to differentiate from primary sclerosing cholangitis (PSC) or other hepatobiliary malignancies. Diagnosis is based on a combination of clinical, biochemical, radiological and histological findings. However, a gold standard diagnostic test is lacking, warranting the identification of more specific disease markers. Novel assays - such as the serum IgG4:IgG1 ratio and IgG4:IgG RNA ratio (which distinguish IgG4-SC from PSC with high serum IgG4 levels), and plasmablast expansion to recognize IgG4-SC with normal serum IgG4 levels - require further validation. Steroids and other immunosuppressive therapies can lead to clinical and radiological improvement when given in the inflammatory phase of the disease, but evidence for the efficacy of treatment regimens is limited. Progressive fibrosclerotic disease, liver cirrhosis and an increased risk of malignancy are now recognized outcomes. Insights into the genetic and immunological features of the disease have increased over the past decade, with an emphasis on HLAs, T cells, circulating memory B cells and plasmablasts, chemokine-mediated trafficking, as well as the role of the innate immune system.

Autoimmune Pancreatitis - A Riddle Wrapped in an Enigma

Autoimmune pancreatitis (AIP) was recognized as a clinical entity, at least in the West little more than 10 years ago. Since then, studies globally, and international collaboration, have led to important advances in our understanding of its clinical features, disease course, and management, although the aetiopathogenesis of this curious disease remains to be fully elucidated. Types 1 and 2 AIP have been described, of which type 1 is the commonest form, and best defined. International consensus now recognizes it as one of the many clinical manifestations of IgG4-related disease, and is now termed IgG4-related pancreatitis (IgG4-RP). The disease is not confined to a particular race, gender, or age, but often presents after the fifth decade in men. A common presentation is with jaundice due to low bile duct obstruction related to diffuse pancreatic enlargement (historically often leading to a misdiagnosis of cancer). Acute pancreatitis is unusual. Other organ involvement is a particular feature, including biliary disease, retroperitoneal fibrosis, generalized lymphadenopathy, renal, and lung involvement. No single test makes the diagnosis, and diagnostic criteria for type 1 AIP/IgG4-RP, which incorporate clinical, laboratory, radiological, pathological, and therapeutic parameters should be applied. A particular attempt should be made to make a histological diagnosis, which is characterized by an IgG4-positive lymphoplasmacytic infiltrate. Management is not based on randomized studies, but corticosteroids are the mainstay of treatment, providing rapid clinical and radiological benefit. However, clinical relapse is common (particularly in type 1 AIP, and in those with associated other organ involvement). Additional immunosuppression may be required, including azathioprine, and rituximab may play an emerging role. The disease course is variable, but loss of organ function (especially pancreatic exocrine failure and pancreatic atrophy) may occur.

Endoscopic retrograde cholangiopancreatography-related adverse events in patients with type 1 autoimmune pancreatitis

BACKGROUND

Endoscopic retrograde cholangiopancreatography (ERCP) is frequently performed for the diagnosis and treatment of type 1 autoimmune pancreatitis (AIP). However, the prevalence of ERCP-related adverse events in patients with type 1 AIP has not been evaluated. We aimed to clarify the feasibility of ERCP in patients with type 1 AIP.

METHODS

We retrospectively reviewed 82 consecutive ERCP procedures performed in patients with type 1 AIP from 2004 to 2014 in one university hospital and three tertiary-care referral centers. One hundred four ERCP procedures in chronic pancreatitis and 1123 in non-AIP cohort were enrolled as control groups. We compared the incidence of post-ERCP pancreatitis (PEP) between type 1 AIP and control groups. We evaluated the incidence of ERCP-related adverse events and various predictive factors for hyperamylasemia after ERCP.

RESULTS

Pancreatography and cholangiography by ERCP were obtained in 78 (95.1%) and 76 (92.7%) patients, respectively. The incidence of PEP, cholangitis, and bleeding was 1.2% (1/82), 0%, and 1.2%, respectively. PEP occurred in type 1 AIP patient with diffuse parenchymal imaging, and the severity was mild. The incidences of PEP were 2.9% (3/104) and 5.4% (61/1123) in chronic pancreatitis and normal cohort, respectively. The incidence of PEP was slightly lower in type 1 AIP than non-AIP cohort (1.2% vs 5.8%, p = 0.119). There were no significant predictive factors for hyperamylasemia after ERCP in type 1 AIP.

CONCLUSIONS

The incidence of ERCP-related adverse events is low in patients with type 1 AIP. ERCP-related procedures are feasible in the diagnosis and treatment of AIP.

Comparison of endoscopic retrograde cholangiopancreatography with papillary biopsy and endoscopic ultrasound-guided pancreatic biopsy in the diagnosis of autoimmune pancreatitis

BACKGROUND

International consensus diagnostic criteria (ICDC) have been proposed for the diagnostic criteria and algorithm of autoimmune pancreatitis (AIP). Although endoscopy is important in the diagnosis of AIP, practical patterns of its usage vary considerably worldwide. This study aimed to compare endoscopic retrograde cholangiopancreatography (ERCP) with papillary biopsy and endoscopic ultrasound (EUS)-guided pancreatic biopsy for diagnosing AIP using ICDC.

METHODS

We retrospectively reviewed and classified 165 Korean patients diagnosed by Korean criteria from June 2007 to October 2013. Among them, 61 patients underwent ERCP with duodenal papillary biopsy (group A) and 62 patients underwent EUS-guided pancreatic biopsy (group B). We analyzed the diagnostic criteria and levels of each criterion, and type of AIP before and after endoscopic procedures.

RESULTS

ERCP with papillary biopsy increased the diagnostic sensitivity from 65.6% (40/61) to 95.1% (58/61) (P < 0.01). EUS-guided pancreatic biopsy increased the diagnostic sensitivity from 50.0% (27/62) to 88.7% (55/62) (P < 0.01). The increases of diagnostic sensitivity in two endoscopic methods were not different statistically. In diagnosing definite AIP, EUS-guided pancreatic biopsy was more useful than ERCP with papilla biopsy (sensitivity; 79.0% vs. 65.6%, P < 0.01). EUS-guided pancreatic biopsy was helpful to classify type 1 and type 2 AIP in some patients. Procedure-related complication (mild pancreatitis) developed in one patient (1.6%) in group A and two patients (3.2%) in group B. ERCP with papillary biopsy was less expensive than EUS-guided pancreatic biopsy.

CONCLUSIONS

Both ERCP with papillary biopsy and EUS-guided pancreatic biopsy are safe and play important roles in diagnosing AIP according to the ICDC.

Endoscopic approaches for the diagnosis of autoimmune pancreatitis

Autoimmune pancreatitis (AIP) is characterized by diffuse pancreatic enlargement and irregular narrowing of the main pancreatic duct (MPD). Immunoglobulin (Ig)G4-related sclerosing cholangitis (IgG4-SC) associated with AIP frequently appears as a bile duct stricture. Therefore, it is important to differentiate AIP and IgG4-SC from pancreatic cancer and cholangiocarcinoma or primary sclerosing cholangitis, respectively. Endoscopy plays a central role in the diagnosis of AIP and IgG4-SC because it provides imaging of the MPD and bile duct strictures as well as the ability to obtain tissue samples for histological evaluations. Diffuse irregular narrowing of MPD on endoscopic retrograde cholangiopancreatography (ERCP) is rather specific to AIP, but localized narrowing of the MPD is often difficult to differentiate from MPD stenosis caused by pancreatic cancer. A long stricture (>1/3 the length of the MPD) and lack of upstream dilatation from the stricture (<5 mm) might be key features of AIP on ERCP. Some cholangiographic features, such as segmental strictures, stric tures of the lower bile duct, and long strictures with prestenotic dilatation, are more common in IgG4-SC than in cholangiocarcinoma. Endoscopic ultrasonography (EUS) reveals diffuse hypoechoic pancreatic enlargement, sometimes with hypoechoic inclusions, in patients with AIP. In addition, EUS-elastography and contrast-enhanced harmonic EUS have been developed with promising results. The usefulness of EUS-guided fine-needle aspiration has been increasingly recognized for obtaining adequate tissue samples for the histological diagnosis of AIP. Further improvement of endoscopic procedures and devices will contribute to more accurate diagnosis of AIP and IgG4-SC.

Biliary and hepatic involvement in IgG4-related disease

BACKGROUND

IgG4-related disease (IgG4-RD) is a multi-systemic disorder. IgG4-related sclerosing cholangitis (IgG4-SC) is the biliary manifestation of the disease, often in association with autoimmune pancreatitis (AIP). Hepatic manifestations of IgG4-RD are less well described within the literature.

AIM

To examine and present an overview of IgG4-RD with a focus on the biliary and hepatic manifestations.

METHODS

An electronic search using Medline was performed. Search items included 'IgG4 multi-system disease, IgG4 associated cholangitis, IgG4 associated liver disease and autoimmune pancreatitis (AIP)'.

RESULTS

IgG4-RD is characterised by an IgG4-positive lymphoplasmacytic tissue infiltrate, storiform fibrosis and an obliterative phlebitis. The HISORt criteria may be used to establish the diagnosis and incorporate a multi-disciplinary approach involving histology, radiology, serum IgG4 levels and response to steroid therapy. IgG4-SC is the commonest extrapancreatic manifestation of type-1 AIP, while the hepatic manifestations remain poorly defined. Important differential diagnoses include primary sclerosing cholangitis, secondary sclerosing cholangitis, cholangiocarcinoma and pancreatic carcinoma. Current treatment regimens remain ill defined although steroid therapy is used first line unless contraindicated. Patients with relapsing disease or multifocal disease should be considered for azathioprine. Available data would also suggest a role for rituximab.

CONCLUSIONS

IgG4-related sclerosing cholangitis is a common manifestation of IgG4-related disease which requires a multi-disciplinary approach to establish the diagnosis. Differentiating IgG4-related sclerosing cholangitis from other conditions, both benign and malignant, is challenging, but vital. Steroids remain the mainstay of treatment. Our understanding of the pathogenesis of the hepatic manifestations of IgG4-related disease continues to evolve.

IgG4 Levels in Bile for Distinguishing IgG4-Associated Cholangiopathy from Other Biliary Disorders: A Single Blinded Pilot Study

Background/Aims

Immunoglobulin G4 (IgG4)-associated cholangiopathy (IAC) is an inflammatory disease and may mimic primary sclerosing cholangitis (PSC), cholangiocarcinoma (CCA), or pancreatic cancer on cholangiography. We investigated whether IgG4 levels in bile aspirated during endoscopic retrograde cholangiopancreatography (ERCP) can distinguish IAC from PSC, CCA, and pancreatic cancer.

Methods

Bile was aspirated directly from the common bile duct during ERCP in patients with IAC prior to steroid therapy. For control purposes, bile was obtained from patients with PSC, CCA, pancreatic cancer, and benign biliary conditions (sphincter of oddi dysfunction/choledocholithiasis).

Results

Biliary IgG4 levels were measured in 54 patients. The median bile IgG4 levels were markedly elevated in patients with IAC (5.5 mg/dL; interquartile range [IQR], 5.1 to 15.6) as compared to patients with benign biliary conditions (0 mg/dL; IQR, 0 to 0.1; p=0.003). The median biliary IgG4 levels in PSC, CCA, and pancreatic cancer were 1.2 (IQR, 0.2 to 3.8), 0.9 (IQR, 0.2 to 3.4), and 0.2 mg/dL (IQR, 0.1 to 0.8), respectively. A cutoff value of 3.8 mg/dL distinguished IAC from PSC and CCA patients with 100% and 76.9% sensitivity and specificity, respectively.

Conclusions

The results of this pilot study suggest that measurement of biliary IgG4 levels may have clinical value in distinguishing patients with IAC from biliary disorders that can mimic IAC.

Major and minor duodenal papillae in autoimmune pancreatitis

OBJECTIVE

The objective of this study was to evaluate picture of the major and minor duodenal papillae in patients with autoimmune pancreatitis (AIP).

METHODS

Endoscopic features of the major and minor papillae were examined in 59 and 13 patients with AIP. After steroid therapy, changes of the major and minor papillae were observed in 5 and 6 patients. The major and minor papillae were observed with narrow band imaging in 24 and 6 patients. Biopsy specimens from the major (n = 50) and minor (n = 13) papillae were immunostained using an anti-IgG4 antibody.

RESULTS

Endoscopic features of the major and minor papillae were abnormal in 26 patients (44%; swelling [n = 20] and redness [n = 14]) and 5 patients (38%; swelling [n = 5]). Swelling of the pancreatic head, irregular narrowing of the main pancreatic duct of the pancreatic head, stenosis of the lower bile duct, and abundant infiltration of IgG4-positive plasma cells were more frequent in the patients with an abnormal major papilla compared with those with a normal major papilla. On narrow band imaging, dilated vessels were observed in abnormal papillae. After therapy, swelling of the major and minor papillae improved in all 4 and 2 patients.

CONCLUSIONS

Endoscopic features of the major and minor papillae were abnormal in 44% and 38% of the patients with AIP.

A comparison of the diagnostic efficacy in type 1 autoimmune pancreatitis based on biopsy specimens from various organs

BACKGROUND

Comprehensive immunostaining evaluation of the biopsy specimens from various organs with type 1 autoimmune pancreatitis (AIP) has not been elucidated. Our aim was to clarify which of these biopsy specimens and counting method could be a useful tool for supporting the diagnosis of AIP.

METHODS

We retrospectively evaluated biopsy specimens from pancreas (n = 19), stomach (n = 28), duodenum (n = 27), duodenal papilla (n = 25), colon (n = 19), liver (n = 11), bile duct (n = 24), and minor salivary gland (n = 13) in 36 patients with AIP. Positive IgG4 immunostaining (>10 plasma cells/high-power field [HPF]) and positive IgG4/IgG ratio (>40%) of biopsy specimens from 8 sites of 6 organs in one HPF and an average from 3 HPFs were compared between AIP and controls.

RESULTS

The sensitivity of IgG4 immunostaining for AIP in one HPF were 16% in pancreas, 14% in stomach, 15% in duodenum, 52% in duodenal papilla, 11% in colon, 27% in liver, 21% in bile duct and 8% in minor salivary gland, respectively. The positive IgG4 immunostaining of the duodenal papilla in one HPF showed the highest sensitivity (52%) and accuracy (73%) among the 8 sites. It also showed the highest sensitivity among 4 different counting methods (IgG4 immunostaining in one HPF and 3 HPFs, both IgG4 immunostaining and IgG/IgG4 ratio in one HPF and 3 HPFs), but there were no significant differences with respect to specificity and accuracy.

CONCLUSIONS

IgG4 immunostaining of swollen duodenal papilla with more than 10 IgG4-positive plasma cells in at least one HPF is useful for supporting the diagnosis of AIP.

Increased immunoglobulin (Ig) G4-positive plasma cell density and IgG4/IgG ratio are not specific for IgG4-related disease in the skin

OBJECTIVES

Immunoglobulin (Ig) G4-related disease (IgG4-RD), a fibroinflammatory condition that can affect multiple organs, is suggested by lymphoplasmacytic inflammation, fibrosis, phlebitis, and increased IgG4+ plasma cell (PC) tissue density. In patients with suspected IgG4-RD and skin changes, skin biopsy may serve as a diagnostic screen or to supplement nondiagnostic visceral biopsy specimens. We aimed to determine whether increased cutaneous IgG4+ PCs or IgG4/IgG ratio is specific for IgG4-RD.

METHODS

We examined 50 mucocutaneous specimens representing seven PC-rich dermatoses and reactive PC-rich infiltrates with IgG and IgG4 immunohistochemical stains.

RESULTS

IgG4+ density exceeded 10 cells per high-power field in 22 (44%) of 50 specimens, representing six of seven diagnoses and reactive infiltrates. In five specimens (10%), the IgG4/IgG ratio exceeded 0.40.

CONCLUSIONS

Moderately elevated IgG4+ PC density or IgG4/IgG ratio is a nonspecific finding in the skin. In cutaneous biopsy specimens showing increased IgG4+ PCs, careful consideration should be given to clinical, serologic, and other histopathologic features before attributing clinical changes to IgG4-RD.

Isolated IgG4-related Disease of Sphenoid Sinus Manifesting as Blindness

Introduction

IgG4 related disease is a rare entity which can affect almost all parts of the body. The available literature of this entity related to paranasal sinuses is very limited.

Presentation of case

We present a case of isolated sphenoid sinus affliction by IgG4 related sclerosing disease manifesting as blindness, which recovered fully with pulsed steroid therapy.

Discussion

We present this case in view of developing insights toward diagnosis and management of IgG4 related sclerosing disease in paranasal sinuses, specifically the sphenoid sinus.

Conclusion

IgG4 disease involving paranasal sinuses (PNS) is rare entity and is managed with pulse methylprednisolone and immunomodulator drugs. Considering the limit of understanding of etiopathogenesis of this disease, surgeon needs to keep this differential diagnosis in mind. It may present atypically like isolated sinus involvement and optic neuritis.

Autoimmune pancreatitis: role of endoscopy in diagnosis and treatment

This review addresses the role of endoscopy in the diagnosis and treatment of autoimmune pancreatitis (AIP) and provides a diagnostic process for patients with suspected AIP. When should AIP be suspected? When can it be diagnosed without endoscopic examination? Which endoscopic approaches are appropriate in suspected AIP, and when? What are the roles of diagnostic endoscopic retrograde pancreatography, endoscopic biopsies, and IgG4 immunostaining? What is the proper use of the steroid trial in the diagnosis of AIP in patients with indeterminate computed tomography imaging? Should biliary stenting be performed in patients with AIP with obstructive jaundice?

Role of endoscopic ultrasonography in the diagnosis of acute and chronic pancreatitis

Endoscopic ultrasonography (EUS) can be a useful tool for detecting underlying causes of acute pancreatitis and establishing the severity of fibrosis in chronic pancreatitis. Ancillary techniques include fine needle aspiration and core biopsy, bile collection for crystal analysis, pancreatic function testing, and celiac plexus block. This review focuses on the role of EUS in the diagnosis of acute and chronic pancreatitis.

Immunoglobulin G4-related gastrointestinal diseases, are they immunoglobulin G4-related diseases?

In immunoglobulin G4 (IgG4)-related disease (RD), organ enlargement or nodular lesions consisting of abundant infiltration of lymphocytes and IgG4-positive plasma cells and fibrosis are seen in various organs. Although infiltration of many IgG4-positive plasma cells is detected in the gastric and colonic mucosa and major duodenal papilla of patients with autoimmune pancreatitis, it cannot be diagnosed as a gastrointestinal lesion involved in IgG4-RD, because none of the following is observed in these lesions: a mass-like formation; dense fibrosis; or obliterative phlebitis. Based on our review of the literature, there appear to be two types of IgG4-related gastrointestinal disease. One is a gastrointestinal lesion showing marked thickening of the wall of the esophagus and stomach, consisting of dense fibrosis with abundant infiltration of IgG4-positive plasma cells, which usually show submucosal spreading. The other is an IgG4-related pseudotumor occurring in gastrointestinal regions such as the stomach, colon, and major duodenal papilla, showing polypoid or mass-like lesions. Most solitary IgG4-related gastrointestinal lesions that are not associated with other IgG4-RD appear to be difficult to diagnose. It is of utmost importance to rule out malignancy. However, these lesions may respond to steroid therapy. To avoid unnecessary resection, IgG4-related gastrointestinal diseases should be considered in the differential diagnosis.

Update on primary sclerosing cholangitis

Primary sclerosing cholangitis (PSC) remains one of the most challenging conditions of clinical hepatology. There has been a steady growth in research to overcome this fact and the present review aims at summarizing the most recently published literature. The main emphasis will be put on the link of recent pathogenetic insights to clinical characteristics and patient management. With regard to pathogenesis, there is no consensus yet as to whether immune mediated injury or factors related to bile acid physiology are the most important. It also remains to be clarified whether PSC is a mixed bag of various secondary etiologies yet to be defined, or a disease entity predominantly represented by sclerosing cholangitis in the context of inflammatory bowel disease. Most important, there is no available medical therapy with proven influence on clinical end points, and timing of liver transplantation and patient follow-up are challenging due to the unpredictable and high risk of cholangiocarcinoma.

Immunoglobulin G4+ clones identified by next-generation sequencing dominate the B cell receptor repertoire in immunoglobulin G4 associated cholangitis

Immunoglobulin G4 (IgG4)-associated cholangitis (IAC) is a manifestation of the recently discovered idiopathic IgG4-related disease. The majority of patients have elevated serum IgG4 levels and/or IgG4-positive B-cell and plasma cell infiltrates in the affected tissue. We hypothesized that clonally expanded, class-switched IgG4-positive B cells and plasma cells could be causal to these poorly understood phenomena. In a prospective cohort of six consecutive IAC patients, six healthy controls, and six disease controls, we used a novel next-generation sequencing approach to screen the B-cell receptor (BCR) repertoires, in blood as well as in affected tissue, for IgG4+ clones. A full repertoire analysis of the BCR heavy chain was performed using GS-FLX/454 and customized bioinformatics algorithms (>10,000 sequences/sample; clones with a frequency ≥0.5% were considered dominant). We found that the most dominant clones within the IgG+ BCRheavy repertoire of the peripheral blood at baseline were IgG4+ only in IAC patients. In all IAC patients, but none of the controls, IgG4+ BCR clones were among the 10 most dominant BCR clones of any immunoglobulin isotype (IgA, IgD, IgM, and IgG) in blood. The BCR repertoires of the duodenal papilla comprised the same dominant IgG4+ clones as the paired peripheral blood samples. In all IAC patients, after 4 and 8 weeks of corticosteroid therapy the contribution of these IgG4+ clones to the IgG+ repertoire as well as to total BCR repertoire was marginalized, mirroring sharp declines in serum IgG4 titers and regression of clinical symptoms.

CONCLUSION

The novel finding of highly abundant IgG4+ BCR clones in blood and tissue of patients with active IAC, which disappear upon corticosteroid treatment, suggests that specific B cell responses are pivotal to the pathogenesis of IAC. (HEPATOLOGY 2013 ).

Immunoglobulin G4-related sclerosing cholangitis: pathologic features and histologic mimics

Since immunoglobulin G4 (IgG4)-related sclerosing cholangitis was first described in 2004, this condition has been recognized as a distinct entity characterized by unique pathologic features. Affected bile ducts show diffuse wall thickening, which represents transmural sclerosing inflammation composed of a dense lymphoplasmacytic infiltrate and fibrosis arranged at least focally in a storiform pattern. A diffuse IgG4-positive plasma cell infiltrate is demonstrable by immunohistochemistry. More than 90% of patients with IgG4-related sclerosing cholangitis have type 1 autoimmune pancreatitis, the remaining presenting as isolated cholangitis. The diagnosis requires a multidisciplinary approach, in which pathologic examination has a critical role. Tissue diagnosis on biopsy specimens (ie, bile duct biopsy, liver needle biopsies) is important, particularly for patients with isolated cholangitis, given the fact that radiological findings of IgG4-cholangitis are not reliable enough for establishing the diagnosis. Furthermore, serum IgG4 levels can be, albeit mildly, elevated in other biliary disorders. Histologic mimics of IgG4-related sclerosing cholangitis include primary sclerosing cholangitis, follicular cholangitis, and sclerosing cholangitis with granulocytic epithelial lesion, the latter 2 being recently described entities.

Autoimmune pancreatitis: an update on classification, diagnosis, natural history and management

Autoimmune Pancreatitis (AIP) is a recently recognized chronic fibro-inflammatory disease of the pancreas. Although rare, its recognition continues to increase worldwide. Patients often present with painless obstructive jaundice mimicking pancreatic cancer. Two subtypes of AIP are known-type 1 is a multi-organ disease associated with IgG4; type 2 appears to be a pancreas-specific disorder. Dramatic response to steroid treatment is characteristic of both forms. A non-invasive diagnosis of type 1 AIP may be possible using diagnostic criteria (in ~70% cases) while diagnosis of type 2 requires histology. These subtypes differ in natural history- type 1 often relapses while initial reports suggest that type 2 does not. Long term complications include endocrine and exocrine insufficiency and in case of type 1, disease relapses and complications from extra-pancreatic involvement. Neither form affects long term survival. The treatment and follow-up guidelines continue to evolve with our increasing experience in AIP.

Sampling at ERCP for cyto- and histopathologicical examination

Sampling at ERCP may be performed at the level of the papilla or of the biliopancreatic ducts. Samples collected at the level of the biliopancreatic ducts allow for diagnosing malignancy with a specificity close to 100% but present a moderate sensitivity in most studies. In this article, the different aspects of sampling at ERCP are discussed, and a special focus is placed on the means that are routinely available to the endoscopist for obtaining a high sensitivity for the diagnosis of malignancy.

IgG4-related disease: can non-classical histopathological features or the examination of clinically uninvolved tissues be helpful in the diagnosis?

IgG4-related disease (IgG4-RD) is an increasingly recognised inflammatory and fibrosing condition that commonly shows multisystem involvement. The disease may mimic malignancy and other inflammatory or immune-mediated disorders, but usually has a good response to corticosteroid therapy, underlining the requirement for recognition of the condition. Accurate diagnosis requires careful interpretation of varying combinations of serum IgG4 levels, radiological features and characteristic histopathological appearances within an appropriate clinical setting. The presence of 'classical' histopathological features together with an elevated tissue IgG4+ plasma cell count and IgG4 to IgG ratio is often diagnostic and at the very least can strongly support a clinicopathological diagnosis of IgG4-RD. The authors describe the most recent diagnostic criteria for IgG4-RD, especially the histopathological features. The authors then discuss the merits of examining tissues that may be more easily obtainable than those that commonly show the 'classical' histopathological features, but within which not all of these 'diagnostic' features may be present. The authors conclude that while a combination of 'classical' histopathological features and an elevated tissue IgG4+ plasma cell count is the gold standard for diagnosis, examination of tissues that show some but not all of these features can, in the appropriate context, provide useful supporting evidence for a clinicopathological diagnosis of IgG4-RD.

Endoscopic diagnosis of biliary tract disease

PURPOSE OF REVIEW

Endoscopic diagnosis of biliary disease is challenging due to difficulties in access, visualization, and sampling. Recent advances in endoscopic technology, ancillary diagnostic methods, and our understanding of autoimmune pancreatitis (AIP) and IgG4-related cholangitis (IRC) have led to improvements in the endoscopic diagnosis of pancreaticobiliary disease.

RECENT FINDINGS

Single-operator cholangioscopy overcomes several of the limitations of mother-baby cholangioscopy enhancing the diagnostic accuracy in indeterminate pancreaticobiliary disease. Probe-based confocal laser endomicroscopy has been recently shown to provide a significantly higher accuracy for the diagnosis of malignant biliary strictures than achieved by endoscopic retrograde cholangiopancreatogram and standard tissue acquisition, and has the potential to develop into a useful adjunct method of cholangioscopy. Fluorescence in-situ hybridization increases the sensitivity of routine brush cytology without compromising specificity in patients with indeterminate biliary strictures. The diagnosis of AIP/IRC remains challenging. The recently published international consensus criteria for AIP have included data on the potential diagnostic utility of endoscopic retrograde pancreatogram and endoscopic ampullary biopsies.

SUMMARY

Recent technical advances as well as ancillary diagnostic methods have improved the diagnostic accuracy of conventional endoscopic techniques. Future refinement of endoscopic methods may further improve diagnostic approaches to biliary disease.

Distinguishing autoimmune pancreatitis from pancreaticobiliary cancers: current strategy

OBJECTIVE

A review of the literature to identify current modalities for the diagnosis of autoimmune pancreatitis (AIP) with the objective of establishing a strategy to distinguish it from pancreaticobiliary cancers.

BACKGROUND

Pancreatic and biliary manifestations of AIP mimic pancreaticobiliary cancers. Misdiagnosis of AIP can result in major surgery for a steroid-responsive disease.

METHODS

A review of the literature was performed to identify recent advances in the diagnosis of AIP and evaluate outcomes with various diagnostic strategies to minimize operative intervention for an autoimmune disease.

RESULTS

Diagnostic criteria for AIP are based on histology, imaging, serology, extrapancreatic organ involvement, and response to steroid therapy. The most commonly involved extrapancreatic sites are bile duct, kidney, and retroperitoneum. The Mayo Clinic diagnostic strategy utilizes core biopsy of the pancreas and the Japanese strategy depends on a characteristic pancreatogram. The rate of operative intervention was similar with both strategies and none of the patients with cancer received steroid therapy. Immunoglobulin G subtype 4 (IgG4)-associated cholangitis mimics cholangiocarcinoma and presence of more than 10 IgG4-positive plasma cells/high power field on endoscopic biopsy of the bile duct was diagnostic for AIP in 88% patients. Biliary complications and early relapse are common after surgical resection and immunomodulatory drugs can maintain long-term remission.

CONCLUSION

Criteria based on histology, imaging, endoscopy, serology, extrapancreatic organ involvement, and response to steroid therapy improve the diagnostic yield for AIP. Application of diagnostic and therapeutic protocols by a multidisciplinary team will optimize outcomes with a decline in the rate of operative intervention for AIP, a steroid-responsive disease with propensity for relapse.

IgG4 Cholangiopathy

IgG4 cholangiopathy can involve any level of the biliary tree which exhibits sclerosing cholangitis or pseudotumorous hilar lesions. Most cases are associated with autoimmune pancreatitis, an important diagnostic clue. Without autoimmune pancreatitis, however, the diagnosis of IgG4-cholangiopathy is challenging. Indeed such cases have been treated surgically. IgG4-cholangiopathy should be diagnosed based on serological examinations including serum IgG4 concentrations, radiological features, and histological evidence of IgG4(+) plasma cell infiltration. Steroid therapy is very effective even at disease relapse. A Th2-dominant immune response or the activation of regulatory T cells seems to be involved in the underlying immune reaction. It is still unknown why IgG4 levels are specifically elevated in patients with this disease. IgG4 might be secondarily overexpressed by Th2 or regulatory cytokines given the lack of evidence that IgG4 is an autoantibody.

IgG4-related sclerosing disease, an emerging entity: a review of a multi-system disease

Immunoglobulin G4-related systemic disease (IgG4-RSD) is a recently defined emerging entity characterized by a diffuse or mass forming inflammatory reaction rich in IgG4-positive plasma cells associated with fibrosclerosis and obliterative phlebitis. IgG4-RSD usually affects middle aged and elderly patients, with a male predominance. It is associated with an elevated serum titer of IgG4, which acts as a marker for this recently characterized entity. The prototype is IgG4-related sclerosing pancreatitis or autoimmune pancreatitis (AIP). Other common sites of involvement are the hepatobiliary tract, salivary gland, orbit, and lymph node, however practically any organ can be involved, including upper aerodigestive tract, lung, aorta, mediastinum, retroperitoneum, soft tissue, skin, central nervous system, breast, kidney, and prostate. Fever or constitutional symptoms usually do not comprise part of the clinical picture. Laboratory findings detected include raised serum globulin, IgG and IgG4. An association with autoantibody detection (such as antinuclear antibodies and rheumatoid factor) is seen in some cases. Steroid therapy comprises the mainstay of treatment. Disease progression with involvement of multiple organ-sites may be encountered in a subset of cases and may follow a relapsing-remitting course. The principal histopathologic findings in several extranodal sites include lymphoplasmacytic infiltration, lymphoid follicle formation, sclerosis and obliterative phlebitis, along with atrophy and destruction of tissues. Immunohistochemical staining shows increased IgG4+ cells in the involved tissues (>50 per high-power field, with IgG4/IgG ratio >40%). IgG4-RSD may potentially be rarely associated with the development of lymphoma and carcinoma. However, the nature and pathogenesis of IgG4-RSD are yet to be fully elucidated and provide immense scope for further studies.

Immunoglobulin G4 immunostaining of gastric, duodenal, or colonic biopsies is not helpful for the diagnosis of autoimmune pancreatitis

BACKGROUND & AIMS

The aim of this study was to evaluate the specificity of the infiltration of digestive tract mucosa by immunoglobulin (Ig) G4-positive plasma cells in patients with autoimmune pancreatitis (AIP), as compared with normal or inflammatory mucosa.

METHODS

Plasma cell infiltration, CD138 and IgG4 immunostaining of digestive biopsies were compared in 4 groups of patients: AIP type 1 (n = 19); AIP type 2 (n = 4) with inflammatory bowel disease (IBD); IBD without pancreatic disorders (n = 20); and controls (n = 26).

RESULTS

With AIP type 1 versus controls, more plasma cells were present in the gastric mucosa of AIP (P = .02) without difference concerning IgG4+ plasma cells at any biopsy site. With AIP type 1 versus IBD, colonic mucosa was more often abnormal (P = .004), and more CD138 (P = .02) and IgG4 plasma cells (P = .0002) were counted in the colon biopsies of IBD. With AIP type 2 versus IBD, no difference for plasma cell and IgG4 infiltration was found.

CONCLUSIONS

IgG4-positive plasma cells are not more numerous in the digestive mucosa of AIP patients than in controls, but they are more abundant in the colon of IBD patients than in AIP patients.

Chronic pancreatitis

PURPOSE OF REVIEW

We review important new clinical observations in chronic pancreatitis made in the past year.

RECENT FINDINGS

Tropical pancreatitis associates with SPINK1 and/or CFTR gene mutations in approximately 50% of patients, similar to the frequency in idiopathic chronic pancreatitis. Corticosteroids increase secretin-stimulated pancreatic bicarbonate concentrations in autoimmune pancreatitis (AIP) by restoring mislocalized CFTR protein to the apical ductal membrane. Most patients with asymptomatic hyperenzymemia have pancreatic lesions of unclear significance or no pancreatic lesions. Common pitfalls in the use of diagnostic tests for exocrine pancreatic insufficiency (EPI) confound interpretation of findings in irritable bowel syndrome and severe renal insufficiency. Further study is needed to improve the accuracy of endoscopic ultrasonography (EUS) to diagnose chronic pancreatitis. Celiac plexus block provides short-term pain relief in a subset of patients.

SUMMARY

Results of this year's investigations further elucidated the genetic associations of tropical pancreatitis, a reversible mislocalization of ductal CFTR in AIP, the association of asymptomatic pancreatic hyperenzymemia with pancreatic disorders, limitations of diagnostic tests for EPI, diagnosis of chronic pancreatitis by EUS and endoscopic pancreatic function testing and treatment of pain.

Recurrent and relapsing pancreatitis

Recurrent acute pancreatitis is a common clinical problem. Most cases of pancreatitis are identified by a careful history and physical examination. Despite advanced evaluation, the cause is not apparent in about 10% of cases. The etiology of recurrent acute pancreatitis appears to be multifactorial, with genetic and environmental influences playing a significant role. The strength of evidence for certain etiologies is highly variable, and natural history data are limited. Controversy exists regarding the most appropriate diagnostic and therapeutic approach. Recurrent acute pancreatitis often represents a continuum with chronic pancreatitis.