IgG4 Cholangiopathy

Immune checkpoint inhibitor-related cholangiopathy: Novel clinicopathological description of a multi-centre cohort

BACKGROUND AND AIMS

Cholestatic liver dysfunction is common in immune-related hepatitis (irH) during treatment with immune checkpoint inhibitors (CPI) for malignancy. We investigated the spectrum of bile duct injury and associated natural history in this cohort.

METHOD

Clinical, laboratory, radiological and histopathological data in patients with evidence of bile duct injury during CPI treatment from 2018 to 2020 was collected in three tertiary hospitals.

RESULTS

In this study, ten patients with confirmed bile duct disease were identified. Pembrolizumab was most commonly implicated (8/10). Median CPI cycles prior to bile duct injury was 6. Median alanine aminotransferase and alkaline phosphatase were 225 U/L and 1549 U/L respectively. Clinical jaundice was seen in 6/10 and radiological evidence of bile duct pathology in 8/10. Of five patients, who had liver biopsy, three cases (including two cases with normal MRCP) showed primary sclerosing cholangitis (PSC) like changes with periductal fibrosis. All patients were treated first-line with prednisolone following cessation of CPI, three with mycophenolate mofetil and one with tacrolimus, with clinical response in four patients. Five patients died after a mean follow-up of 27 weeks; cause of death was primarily related to progression of malignancy.

CONCLUSION

Within this heterogeneous cohort, we identified that CPI-related cholangiopathy responded poorly to immunosuppression and potentially progressed to bile duct loss. Thorough radiological and histological assessment is recommended, as identification of the cholangiopathy-associated phenotype may permit more informed advice regarding prognosis. Further data is required to determine detailed immunological characterisation in order to identify individuals at an increased risk of developing cholangiopathy.

Immunoglobulin G4 Cholangiopathy Masquerading as a Klatskin Tumor: An Interesting Case

Immunoglobulin G4 (IgG4) cholangiopathy is used to describe regional biliary involvement in a systemic fibro-inflammatory and infiltrative disease, IgG4-related disease. Occasionally, it tends to present with localized disease leading to an extensive workup to rule out malignancy and infections, especially since IgG4-related disease is an uncommon entity. Herein, we present a case of a 68-year-old male who presented with pruritus and steatorrhea with imaging studies revealing a biliary hilar mass concerning for malignancy. Subsequent extensive testing was inconclusive of malignancy and finally noted to have elevated IgG4 levels as part of a broader workup. The patient was started on prednisone with the resulting improvement in his symptoms and the imaging findings.

Anti-interferon-gamma autoantibody related disseminated nontuberculous mycobacteriosis with pathological features of immunoglobulin G4-related disease

A 72-year-old man who was diagnosed as pulmonary mycobacterium avium complex (MAC) disease had suffered from antibiotics resistant fever with left renal enlargement surrounded by inflammatory change and multiple osteolytic lesions on computed tomography (CT). The renal biopsied samples pathologically showed immunoglobulin G4 (IgG4) positive plasma cell infiltration and many acid-fast bacilli without granuloma formation. Nucleic acid identification test for MAC from the samples of vertebral osteolytic lesion was positive. In the autopsy samples from left kidney, epithelioid cell granuloma and Langhans giant cell with many acid-fast bacilli were shown pathologically. In addition to osteolytic lesions on CT study, these pathological findings were not consistent with IgG4-related disease (IgG4-RD). The diagnosis of disseminated nontuberculous mycobacteriosis was made, and plasma anti-interferon-gamma (IFN-γ) autoantibody was found as the cause of underlying immunodeficiency. Disturbed function of IFN-γ resulted in impaired ability of phagocytic cells against pathogens and leading to spread of infection. T-helper type 2 dominant immune response was induced by prolonged antigenic stimulation of mycobacteria, which might have contributed to form the pathological features of IgG4-RD.

Non-neoplastic cholangiopathies: an algorithmic approach

Cholangiopathies are chronic diseases that affect the bile ducts, comprising a heterogeneous group of progressive and potentially fatal entities. The diagnosis of these diseases is a great challenge for radiologists because of the overlapping of their clinical, biochemical, and imaging findings. Nevertheless, identifying the precise etiology is crucial, given that the therapeutic options are distinct and influence the prognosis of the patient. The purpose of this review article is to discuss some of the non-neoplastic causes of cholangiopathies and to provide a useful diagnostic algorithm.

IgG4-Related Sclerosing Cholangitis: A Clinical and Imaging Review

OBJECTIVE. The purpose of this article is to present the pathologic and clinical features of IgG4-related sclerosing cholangitis (ISC), illustrate the associated imaging findings, and discuss treatment of the disorder. CONCLUSION. ISC is an inflammatory disorder involving the biliary system and resulting in strictures. Although often associated with autoimmune pancreatitis, it may be an isolated disease. Differentiation of ISC from other forms of cholangitis and cholangiocarcinoma is difficult but necessary for management. Imaging is important in diagnosing and assessing the extent of disease and planning a management strategy.

IgG4-Related Cholangiopathy and Its Mimickers: A Case Report and Review Highlighting the Importance of Early Diagnosis

Immunoglobulin (Ig) G4 (IgG4)-related disease is a recently described clinical entity that can involve multiple organs. It is an autoimmune disorder characterized by a dense lymphoplasmacytic infiltrate, storiform fibrosis, and obliterative phlebitis. A key distinguishing factor is its dramatic response to steroid therapy. Although best described in cases of autoimmune pancreatitis, IgG4-related disease has also been implicated in patients with cholangitis and is now commonly referred to as IgG4-related cholangiopathy. It is characterized by elevated serum IgG4 levels, an IgG4-positive plasma cell infiltration with storiform fibrosis/obliterative phlebitis of the bile duct wall, and a response to steroids. It is crucial to differentiate IgG4-related cholangiopathy from its mimickers, such as primary biliary cholangitis, secondary biliary cholangitis, primary sclerosing cholangitis, secondary sclerosing cholangitis, and cholangiocarcinoma, because treatment modalities and outcomes of IgG4-related cholangiopathy differ significantly from these disorders. Here, we present an interesting case of IgG4-related cholangiopathy, discuss clinical and pathological features crucial to its early diagnosis, and compare and contrast this condition with its potentially confounding mimickers.

IgG4-related sclerosing cholangitis: all we need to know

Our knowledge and experience of IgG4-related sclerosing cholangitis (ISC) have expanded in the last decade. ISC is one of the common organ manifestations of IgG4-related disease (IgG4-RD); approximately 60 % of patients with this systemic condition have ISC in the proximal and/or distal bile ducts. ISC needs to be discriminated from primary sclerosing cholangitis, cholangiocarcinoma, and other rare forms of lymphoplasmacytic cholangiopathy (e.g., follicular cholangitis and sclerosing cholangitis with granulocytic epithelial lesions). Its diagnosis requires a multidisciplinary approach, in which serology, histology, and imaging play crucial roles. Treatments with high-dose corticosteroids typically lead to the rapid and consistent induction of disease remission. Another promising therapeutic approach is B-cell depletion with rituximab. Although disease relapse is relatively common, provided that appropriate treatments are administered, ISC is considered a "benign" disease with a low risk of liver failure and biliary malignancy. Its molecular pathology is characterized by Th2-dominant immune reactions, regulatory T-cell activation, and CCL1-CCR8 interactions. Particular subsets of B cells such as plasmablasts and regulatory B cells also expand. A recent global proteomic study demonstrated that three significantly activated immunological cascades in ISC were all B-cell- or immunoglobulin-related (Fc-gamma receptor-mediated phagocytosis, B-cell receptor signaling pathway, and Fc-epsilon receptor I signaling pathway), suggesting the crucial roles of B cells in the underlying immune reactions. Despite the expansion of our knowledge of the pathophysiology of ISC, the exact role of IgG4 remains unclear. A better understanding of its immunopathology will offer some potential drug targets for this emerging biliary disease.

IgG4-Associated Cholangitis Can Mimic Hilar Cholangiocarcinoma

IgG4-associated cholangitis can mimic hilar cholangiocarcinoma. Previously reported patients with IgG4-associated cholangitis mimicking cholangiocarcinoma had elevated serum IgG4 levels and long-segment biliary strictures. However, in the absence of other diagnostic criteria for malignancy, IgG4-associated cholangitis should remain a consideration among patients with normal serum IgG4 and a hilar mass suspicious for cholangiocarcinoma. The presence of a hilar mass and a malignant-appearing biliary stricture in two patients with normal serum IgG4 prompted further evaluation and subsequent concomitant liver and bile duct resection and reconstruction. The diagnosis of IgG4-associated cholangitis was established during the pathologic evaluation of the resected specimens. IgG4-associated cholangitis is a known imitator of hilar cholangiocarcinoma and should be considered in the differential diagnosis even among serologically IgG4-negative patients with a hilar mass prior to operative resection.

"Biliary Diseases with Pancreatic Counterparts": Cross-sectional Imaging Findings

On the basis of the similarities in the histopathologic findings and the clinical-biologic behaviors of select biliary and pancreatic conditions, a new disease concept, "biliary diseases with pancreatic counterparts," has been proposed. Both nonneoplastic and neoplastic pathologic conditions of the biliary tract have their counterparts in the pancreas. Immunoglobulin G4 (IgG4)-related sclerosing cholangitis is the biliary manifestation of IgG4-related sclerosing disease, and type 1 autoimmune pancreatitis is its pancreatic counterpart. People with chronic alcoholism can develop peribiliary cysts and fibrosis as well as pancreatic fibrosis and chronic pancreatitis simultaneously. Pancreatic ductal adenocarcinoma, intraductal papillary mucinous neoplasm, and mucinous cystic neoplasm are considered pancreatic counterparts for the biliary neoplasms of extrahepatic cholangiocarcinoma, intraductal papillary neoplasm of the biliary tract, and hepatic mucinous cystic neoplasm, respectively. The anatomic proximity of the biliary tract and the pancreas, the nearly simultaneous development of both organs from the endoderm of the foregut, and the presence of pancreatic exocrine acini within the peribiliary glands surrounding the extrahepatic bile ducts are suggested as causative factors for these similarities. Interestingly, these diseases show "nearly" identical findings at cross-sectional imaging, an observation that further supports this new disease concept. New information obtained with regard to biliary diseases can be used for evaluation of pancreatic abnormalities, and vice versa. In addition, combined genetic and molecular studies may be performed to develop novel therapeutic targets. For both biliary and pancreatic diseases, imaging plays a pivotal role in initial diagnosis, evaluation of treatment response, efficacy testing of novel drugs, and long-term surveillance.

IgG4-Seronegative Autoimmune Pancreatitis and Sclerosing Cholangitis

IgG4-related disease is a relatively novel clinical entity whose gastrointestinal manifestations include type 1 autoimmune pancreatitis (AIP) and IgG4-associated sclerosing cholangitis. The presence of elevated serum IgG4 is suggestive but not essential for the diagnosis of type 1 AIP and is a pervasive feature of the proposed diagnostic criteria. The differential diagnosis of type 1 AIP includes malignant conditions, emphasizing the importance of a deliberate, comprehensive evaluation. Management of patients with a suggestive clinical presentation, but without serum IgG4 elevation, is difficult. Here we present three cases of IgG4-seronegative AIP and sclerosing cholangitis that responded to empiric steroid therapy and discuss approach considerations. These cases demonstrate the value of meticulous application of existing diagnostic algorithms to achieve a clinical diagnosis and avoid surgical intervention.

Autoimmune pancreatitis mimicking Klatskin tumour on radiology

Autoimmune pancreatitis (AIP) is categorised into two distinct types, AIP type 1 and 2. Although there can be multisystem involvement, rarely, the cholangitis associated with AIP can present radiologically in a manner similar to that of Klatskin tumour. We present the case of a 65-year-old man who was almost misdiagnosed with a Klatskin tumour because of the similarity in radiological features of the two aforementioned clinical entities. The patient presented with a history of jaundice, pruritus and abdominal pain, and work up showed deranged liver function tests, elevated cancer antigen 19-9 levels and positive antinuclear antibodies. CT scan of the abdomen showed findings suggestive of Klatskin tumour but due to diffuse enlargement of the pancreas and surrounding low-attenuation halo found on a closer review, a diagnosis of AIP was performed. The patient was started on standard corticosteroid therapy and responded well, with complete resolution of the radiological findings.

Immunoglobulin G4-related pancreatic and biliary diseases

BACKGROUND

Autoimmune pancreatitis and autoimmune cholangitis are new clinical entities that are now recognized as the pancreatico-biliary manifestations of immunoglobulin (Ig) G4-related disease.

OBJECTIVE

To summarize important clinical aspects of IgG4-related pancreatic and biliary diseases, and to review the role of IgG4 in the diagnosis of autoimmune pancreatitis (AIP) and autoimmune cholangitis (AIC).

METHODS

A narrative review was performed using the PubMed database and the following keywords: "IgG4", "IgG4 related disease", "autoimmune pancreatitis", "sclerosing cholangitis" and "autoimmune cholangitis". A total of 955 articles were retrieved; of these, 381 contained relevant data regarding the IgG4 molecule, pathogenesis of IgG-related diseases, and diagnosis, management and long-term follow-up for patients with AIP and AIC. Of these 381 articles, 66 of the most pertinent were selected.

RESULTS

The selected studies demonstrated the increasing clinical importance of both AIP and AIC, which can mimic pancreatic cancer and cholangiocarcinoma, respectively. IgG4 titration in tissue or blood cannot be used alone to diagnose all IgG4-related diseases; however, it is often a useful adjunct to clinical, radiological and histological features. AIP and AIC respond to steroids; however, relapse is common and long-term maintenance treatment often required.

CONCLUSIONS

A review of the diagnosis and management of both AIC and AIP is timely and pertinent to clinical practice because the amount of information regarding these conditions has increased substantially in the past few years, resulting in significant impact on the clinical management of affected patients.

Chronic cholestatic liver diseases: clues from histopathology for pathogenesis

Chronic cholestatic liver diseases include fibrosing cholangiopathies such as primary biliary cirrhosis or primary sclerosing cholangitis. These and related cholangiopathies clearly display pathologies associated with (auto)immunologic processes. As the cholangiocyte's apical membrane is exposed to the toxic actions of the bile fluid, the interaction of bile with cholangiocytes and the biliary tree in general must be considered to completely understand the pathogenesis of cholangiopathies. While the molecular processes involved in the hepatocellular formation of bile are well understood in both normal and pathophysiologic conditions, those in the bile ducts of normal liver and in livers with cholangiopathies lag behind. This survey highlights key mechanisms known to date that are important for the formation of bile by hepatocytes and its modification by the biliary tree. It also delineates the clinical pathophysiologic findings for cholangiopathies and puts them in perspective with current experimental models to reveal the pathogenesis of cholangiopathies and develop novel therapeutic approaches.

IgG4-related Disorders of the Gastrointestinal Tract

IgG4-related disease, a newly established multisystemic disease can affect virtually every organ. Histologically, it is characterized by the presence of a dense lymphoplasmacytic infiltrate, storiform-type fibrosis, and obliterative phlebitis. The disease shows elevated serum and tissue IgG4. The pancreas and hepatobiliary tract are involved far more commonly than the tubular gut. This review summarizes the clinical and pathologic features of the gastrointestinal manifestations of IgG4-related disease and discusses the wide spectrum of diseases that this entity may mimic.

Endoscopic management of benign bile duct strictures

The use of endoscopic retrograde cholangiopancreatography for treating benign biliary strictures has become the standard of practice, with surgery and percutaneous therapy reserved for selected patients. The gold-standard endoscopic therapy is dilation of the stricture followed by placing and exchanging progressively larger and more numerable plastic stents over a 1-year period. Newer modalities, including the use of fully covered metal stents, are currently under investigation in an effort to improve the treatment of benign biliary strictures.

Recent advances in research of immunoglobulin G4-related sclerosing cholangitis

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is a recently defined disease entity characterized by elevated serum IgG4, chronic progressive obstructive jaundice, and diffuse or mass-forming inflammatory reaction rich in IgG4-positive plasma cells and lymphocytes associated with fibrosclerosis and obliterative phlebitis, which shares a number of clinical, biochemical, and radiological features with primary sclerosing cholangitis (PSC) or cholangiocarcinoma (CC). IgG4-SC is commonly associated with autoimmune pancreatitis (AIP). Steroid therapy comprises the mainstay of treatment for IgG4-SC patients. However, liver transplantation is the only useful treatment for PSC patients, and CC patients require surgical therapy. Therefore, the accurate discrimination between IgG4-SC and PSC or CC is a very important issue. In this article, we will review the features and role of immunoglobulin G4 (IgG4), the diagnosis and therapy of IgG4-SC, and the relations between IgG4-SC and AIP, PSC or CC.

Klatskin-like lesions

Hilar cholangiocarcinoma, also known as Klatskin tumour, is the commonest type of cholangiocarcinoma. It poses unique problems in the diagnosis and management because of its anatomical location. Curative surgery in the form of major hepatic resection entails significant morbidity. About 5-15% of specimens resected for presumed Klatskin tumour prove not to be cholangiocarcinomas. There are a number of inflammatory, infective, vascular, and other pathologies, which have overlapping clinical and radiological features with a Klatskin tumour, leading to misinterpretation. This paper aims to summarise the features of such Klatskin-like lesions that have been reported in surgical literature.

Diagnostic Dilemma in a Patient with Jaundice: How to Differentiate between Autoimmune Pancreatitis, Primary Sclerosing Cholangitis and Pancreas Carcinoma

A 68-year-old male patient was referred to our institution in May 2011 for a suspected tumor in the pancreatic head with consecutive jaundice. Using magnetic resonance imaging, further differentiation between chronic inflammation and a malignant process was not possible with certainty. Apart from cholestasis, laboratory studies showed increased values for CA 19-9 to 532 U/ml (normal <37 U/ml) and hypergammaglobulinemia (immunoglobulin G, IgG) of 19.3% (normal 8.0–15.8%) with an elevation of the IgG4 subtype to 2,350 mg/l (normal 52–1,250 mg/l). Endoscopic retrograde cholangiopancreatography revealed a prominent stenosis of the distal ductus hepaticus communis caused by pancreatic head swelling and also a bihilar stenosis of the main hepatic bile ducts. Cytology demonstrated inflammatory cells without evidence of malignancy. Under suspicion of autoimmune pancreatitis with IgG4-associated cholangitis, immunosuppressive therapy with steroids and azathioprine was started. Follow-up endoscopic retrograde cholangiopancreatography after 3 months displayed regressive development of the diverse stenoses. Jaundice had disappeared and blood values had returned to normal ranges. Moreover, no tumor of the pancreatic head was present in the magnetic resonance control images. Due to clinical and radiological similarities but a consecutive completely different prognosis and therapy, it is of fundamental importance to differentiate between pancreatic cancer and autoimmune pancreatitis. Especially, determination of serum IgG4 levels and associated bile duct lesions induced by inflammation should clarify the diagnosis of autoimmune pancreatitis and legitimate immunosuppressive therapy.