Classification and Diagnostic Criteria for IgG4-Related Sclerosing Cholangitis

Management of IgG4-related cholangitis: diagnosis, therapy, and long-term surveillance

IgG4-related cholangitis (IRC) is a chronic cholestatic liver disease that often occurs concomitantly with autoimmune pancreatitis type 1. Both conditions are manifestations of IgG4-related disease, a systemic autoimmune-mediated fibroinflammatory disorder. Patients often present with jaundice and weight loss, mimicking hepatobiliary malignancies, such as cholangiocarcinoma, primary sclerosing cholangitis, and pancreatic cancer. Accurate diagnosis is challenging due to the absence of pathognomonic findings but can be achieved using the HISORt criteria (histology, imaging, serology, other organ involvement, and response to immunosuppressive therapy). Early diagnosis is critical to avoid unnecessary surgery and prevent progression to liver fibrosis or cirrhosis. IRC responds well to corticosteroid therapy, though relapses are common, necessitating long-term immunosuppressive treatment in many cases. Steroid-sparing agents for remission induction and maintenance therapy comprise immunomodulators, such as azathioprine, as well as B-cell depletion therapies, such as rituximab. This review provides a structured clinical overview of the diagnosis, differential diagnosis, and therapy, including novel therapeutic options, such as inebilizumab, for this rare yet severe condition. A key focus is on long-term surveillance strategies, which include laboratory tests, imaging (contrast-enhanced magnetic resonance imaging/magnetic resonance cholangiopancreatography, ultrasound, endosonography), and, particularly in patients with fibrotic bile duct strictures, endoscopy (endoscopic retrograde cholangiopancreatography, cholangioscopy).

Journey to diagnosis: An unfinished exploration of IgG4-related sclerosing cholangitis

IgG4-related sclerosing cholangitis (IgG4-SC) is an inflammatory disease that leads to bile duct stricture, characterized by the infiltration of IgG4-positive plasma cells into the bile duct wall, thickening of the bile duct wall, and narrowing of the lumen. The differential diagnosis of IgG4-SC mainly includes primary sclerosing cholangitis, cholangiocarcinoma, and pancreatic cancer. IgG4-SC is often associated with autoimmune pancreatitis and can be accurately diagnosed based on clinical diagnostic criteria. However, isolated IgG4-SC is difficult to distinguish from biliary tumors. Given the significant differences in biological behavior, treatment, and prognosis between these diseases, accurately identifying isolated IgG4-SC has very important clinical significance.

A Review of IgG4-related Sclerosing Cholangitis (IgG4-SC)

IgG4-related sclerosing cholangitis (IgG4-SC) is a unique, steroid-responsive, fibroinflammatory condition that is more commonly found in older men and is strongly associated with autoimmune pancreatitis (AIP). It may pose a diagnostic challenge at times due to closely mimicking hepatobiliary diseases such as primary sclerosing cholangitis (PSC), secondary sclerosing cholangitis (SSC), and cholangiocarcinoma. IgG4-SC has an excellent prognosis when promptly diagnosed and treated with steroids. Literature search strategy: The authors searched PubMed and Google Scholar, for articles with the search terms "autoimmune cholangiopathy" and "IgG4 cholangiopathy."

Endoscopic Ultrasound and Intraductal Ultrasound in the Diagnosis of Biliary Tract Diseases: A Narrative Review

Endoscopic ultrasound (EUS) and intraductal ultrasound (IDUS) play very important roles in the field of biliary tract disease. Because of their excellent spatial resolution, the detection of small lesions and T- or N-staging of tumors have become possible. Additionally, contrast-enhanced EUS and the new imaging technique of detective flow imaging are reported to be useful for differential diagnosis. Furthermore, EUS-guided tissue acquisition is used not only for pathological diagnosis but also to collect tissue samples for cancer genome profiling. This review provides an overview of diagnosis utilizing the features and techniques of EUS and IDUS.

Unexpected diagnosis: IgG4-related sclerosing cholangitis with normal serum IgG4 levels - Unraveling diagnostic and therapeutic challenges

Diagnosing IgG4-related sclerosing cholangitis (IgG4-SC) presents significant challenges, especially when serum IgG4 levels are normal and other organs are not involved. We report a case of a 51-year-old patient with typical symptoms of biliary obstruction, including jaundice and abdominal pain. Despite normal serum IgG4 levels, imaging suggested cholangiocarcinoma, leading to extensive surgical intervention. Histological analysis of the surgical specimen revealed extensive lymphoplasmacytic infiltration and numerous IgG4-positive plasma cells, confirming IgG4-SC. This case underscores the difficulty in differentiating IgG4-SC from other biliary diseases such as primary sclerosing cholangitis and cholangiocarcinoma, highlighting the need for thorough histological examination in atypical presentations.

Case report: Isolated immunoglobulin G4-related sclerosing cholangitis misdiagnosed as hilar cholangiocarcinoma

Background

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is frequently accompanied with type 1 autoimmune pancreatitis (AIP). Isolated IgG4-SC which is not accompanied with AIP is uncommon in clinical practice, and its manifestations are similar to those of hilar cholangiocarcinoma.

Case presentation

A 55-year-old male presented with persistent aggravation of icteric sclera and skin. He was initially diagnosed with hilar cholangiocarcinoma and underwent surgery. However, positive IgG4 plasma cells were found in the surgical specimens. Thus, a pathological diagnosis of IgG4-SC was established. After that, steroid therapy was given and initially effective. But he was steroid dependent, and then received rituximab therapy twice. Unfortunately, the response to rituximab therapy was poor.

Conclusion

It is crucial to differentiate isolated IgG4-SC from hilar cholangiocarcinoma to avoid unnecessary surgery. Future studies should further explore effective treatment strategy in patients who do not respond to steroids therapy. It is also required to develop novel and accurate diagnostic approaches to avoid unnecessary surgical procedures.

Immunoglobulin G4-related Hepatopathy after COVID-19 Vaccination

An 84-year-old woman with immunoglobulin G4 (IgG4)-related disease presented with jaundice and liver dysfunction after COVID-19 vaccination. Serum IgG4 levels were elevated. Diagnostic imaging showed no stenotic lesions in the bile ducts. A liver biopsy was performed because of the enlarged liver. Infiltration of IgG4-positive plasma cells, which accounted for approximately 74% of total plasma cells, was found in the portal area, but there was no evidence of periportal hepatitis, and inflammatory cell infiltration into the lobular space was minimal. IgG4-related hepatopathy was diagnosed. The patient achieved spontaneous remission with no treatment and only follow-up and remains under observation at the time of writing.

Inflammasome and pyroptosis in autoimmune liver diseases

Autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and IgG4-related sclerosing cholangitis (IgG4-SC) are the four main forms of autoimmune liver diseases (AILDs), which are all defined by an aberrant immune system attack on the liver. Most previous studies have shown that apoptosis and necrosis are the two major modes of hepatocyte death in AILDs. Recent studies have reported that inflammasome-mediated pyroptosis is critical for the inflammatory response and severity of liver injury in AILDs. This review summarizes our present understanding of inflammasome activation and function, as well as the connections among inflammasomes, pyroptosis, and AILDs, thus highlighting the shared features across the four disease models and gaps in our knowledge. In addition, we summarize the correlation among NLRP3 inflammasome activation in the liver-gut axis, liver injury, and intestinal barrier disruption in PBC and PSC. We summarize the differences in microbial and metabolic characteristics between PSC and IgG4-SC, and highlight the uniqueness of IgG4-SC. We explore the different roles of NLRP3 in acute and chronic cholestatic liver injury, as well as the complex and controversial crosstalk between various types of cell death in AILDs. We also discuss the most up-to-date developments in inflammasome- and pyroptosis-targeted medicines for autoimmune liver disorders.

Secondary sclerosing cholangitis and IgG4-sclerosing cholangitis - A review of cholangiographic and ultrasound imaging

Sclerosing cholangitis (SC) represents a spectrum of chronic progressive cholestatic diseases of the intrahepatic and/or extrahepatic biliary system characterized by patchy inflammation, fibrosis, and stricturing. Primary and secondary SC must be distinguished given the different treatment modalities, risks of malignancy, and progression to portal hypertension, cirrhosis, and hepatic failure. This review focuses on secondary SC and the pathogenic mechanisms, risk factors, clinical presentation, and novel imaging modalities that help to distinguish between these conditions. We explore the detailed use of cholangiography and ultrasound imaging techniques.

Histological evaluation in biliary diseases

PURPOSE OF REVIEW

This review focuses on recent developments of histopathology in the most common biliary disorders affecting adults. The reader is referred to other sources for the specialized topics on paediatric populations and post liver transplantation.

RECENT FINDINGS

Fibrosis stage at diagnosis is an independent predictor of liver transplant-free survival in patients with primary biliary cholangitis. Immunohistochemistry might have an important role in predicting response to treatment. New histological scoring systems with excellent correlation with long-term clinical outcomes are being developed in primary sclerosing cholangitis (PSC). Quantification of fibrosis with collagen proportionate area can improve risk stratification and could be particularly useful to assess treatment response in PSC.Gene sequencing on cytology and intrabiliary biopsy may improve risk stratification for cholangiocarcinoma. Genetic variants of ATP8B1, ABCB11 and ABCB4 are relatively common in adults with cholestatic liver disease. New causes of cholestatic liver injury have recently been described.

SUMMARY

Histology is often not necessary for the diagnosis of biliary disease, but can provide important information that may assist the clinician in patients' management. Histopathology remains crucial to confirm a diagnosis of cholangiocarcinoma, and to identify the pattern of biliary injury in immune-mediated cholangiopathies and rarer pathological entities.