IgG4-associated cholangitis

IgG4-related diseases of the digestive tract

IgG4-related conditions affecting the digestive tract are part of a multi-organ fibro-inflammatory disorder termed IgG4-related disease (IgG4-RD), with autoimmune pancreatitis and IgG4-related cholangitis being the most prominent manifestations. Gastrointestinal symptoms include jaundice, weight loss, abdominal pain, biliary strictures, and pancreatic and hepatic masses that mimic malignant diseases. IgG4-RD manifestations occur less frequently elsewhere in the digestive tract, namely in the oesophagus, retroperitoneum or intestine. Evidence-based European guidelines frame the current state-of-the-art in the diagnosis and management of IgG4-related digestive tract disease. Diagnosis is based on histology (if available), imaging, serology, other organ involvement and response to therapy (HISORt criteria). Few biomarkers beyond serum IgG4 concentrations are reliable. The first-line therapy (glucocorticoids) is swiftly effective but disease flares are common at low doses or after tapering. Second-line therapy might consist of other immunosuppressive drugs such as thiopurines or rituximab. Further trials, for example, of anti-CD19 drugs, are ongoing. Although an association between IgG4-RD and the development of malignancies has been postulated, the true nature of this relationship remains uncertain at this time.

IgG4-Associated Cholangitis in Patients Resected for Presumed Perihilar Cholangiocarcinoma: a 30-Year Tertiary Care Experience

BACKGROUND

Distinguishing perihilar cholangiocarcinoma (PHC) from benign forms of sclerosing cholangitis affecting the hilar bile ducts is challenging, since histological confirmation of PHC is difficult to obtain and accurate non-invasive diagnostic tests are not available. IgG4-associated cholangitis (IAC), an imitator of PHC, may present with clinical and radiographical signs of PHC. IAC can be accurately diagnosed with a novel qPCR test. The aim of this study was to investigate the incidence and long-term activity of IAC in patients resected for PHC in a single tertiary center over a period of 30 years.

METHODS

All patients with benign disease who underwent surgery for presumed PHC in our institute between 1984 and 2015 were identified. Benign liver and bile duct specimens were re-evaluated by a pathologist and scored according to international consensus pathology criteria for IgG4-related disease (IgG4-RD). Patients with benign disease still alive were followed-up and a clinical diagnosis of IAC was made using a combination of the HISORt group C (response to steroids) criteria and elevated serum IgG4 levels and/or the novel IgG4/IgG RNA ratio. Also, recurrent symptomatic disease at any time after surgery requiring immunosuppression was assessed.

RESULTS

Out of 323 patients who underwent surgery for presumed PHC, 50 patients (15%) had benign disease. In 42% (n = 21/50) of these patients a histological (n = 17) or clinical (n = 4) diagnosis of IAC was established. The remaining patients were diagnosed with unclassified sclerosing inflammation, cystadenoma, or sclerosing hemangioma. Nine out of 12 IAC patients who were followed-up showed episodes of recurrent disease requiring immunosuppressive treatment.

CONCLUSIONS

Liver and bile duct resections for PHC during three decades disclosed in 15% benign biliary disorders mimicking PHC of which 42% were definitely diagnosed as IAC. IgG4-RD remains active in the majority of patients with IAC years after surgery. Novel diagnostic tests for IAC might reduce misdiagnosis, unnecessary surgery, and life-threatening complications.

Cholangitis: Diagnosis, Treatment and Prognosis

Cholangitis is a serious life-threatening situation affecting the hepatobiliary system. This review provides an update regarding the clinical and pathological features of various forms of cholangitis. A comprehensive search was performed in the PubMed, Scopus, and Web of Knowledge databases. It was found that the etiology and pathogenesis of cholangitis are heterogeneous. Cholangitis can be categorized as primary sclerosing (PSC), secondary (acute) cholangitis, and a recently characterized form, known as IgG4-associated cholangitis (IAC). Roles of genetic and acquired factors have been noted in development of various forms of cholangitis. PSC commonly follows a chronic and progressive course that may terminate in hepatobiliary neoplasms. In particular, PSC commonly has been associated with inflammatory bowel disease. Bacterial infections are known as the most common cause for AC. On the other hand, IAC has been commonly encountered along with pancreatitis. Imaging evaluation of the hepatobiliary system has emerged as a crucial tool in the management of cholangitis. Endoscopic retrograde cholangiography, magnetic resonance cholangiopancreatography and endoscopic ultrasonography comprise three of the modalities that are frequently exploited as both diagnostic and therapeutic tools. Biliary drainage procedures using these methods is necessary for controlling the progression of cholangitis. Promising results have been reported for the role of antibiotic treatment in management of AC and PSC; however, immunosuppressive drugs have also rendered clinical responses in IAC. With respect to the high rate of complications, surgical interventions in patients with cholangitis are generally restricted to those patients in whom other therapeutic approaches have failed.

Advances in research of immunoglobulin G4-related sclerosing cholangitis

Immunoglobulin G4 (IgG4)-related sclerosing cholangitis is a special form of cholangitis. As an autoimmune disease, IgG4-related sclerosing cholangitis has no specific clinical manifestations, and its pathogenesis remains unclear. In patients with this disease, serum concentration of IgG4 is elevated, intrahepatic or extrahepatic bile duct stenosis associated with biliary wall thickening is often revealed by biliary imaging, autoimmune diseases such as autoimmune pancreatitis may be present, and massive IgG4 positive plasma cell infiltration and widespread bile duct wall fibrosis are often showed by histopathological examination. It is often difficult to differentiate IgG4-related sclerosing cholangitis from primary sclerosing cholangitis, secondary sclerosing cholangitis and bile duct cancer. However, the disease is sensitive to hormone therapy. This article will review the current advances in research of IgG4-related sclerosing cholangitis.

A global proteomic study identifies distinct pathological features of IgG4-related and primary sclerosing cholangitis

AIMS

This combined proteomic and histopathological study was aimed to compare tissue characteristics of immunoglobulin (Ig)G4-related sclerosing cholangitis (ISC) and primary sclerosing cholangitis (PSC) in a global, non-biased manner.

METHODS AND RESULTS

Tissue proteomes and phosphorylomes of frozen large bile duct samples were analysed by a conventional liquid chromatography-tandem mass spectrometry (LC-MS/MS) protocol and additional phosphopeptide enrichment methods. The proteomic examination identified 23 373 peptides and 4870 proteins, including 4801 phosphopeptides and 1121 phosphoproteins. The expression profiles of phosphopeptides discriminated ISC from PSC more clearly than those of non-phosphopeptides. In the pathway analysis, ISC was found to have 11 more activated signal cascades, including three immunological pathways, all B cell- or immunoglobulin-related. On immunostaining, two immunological markers (FYN-binding protein and allograft inflammatory factor-1) up-regulated in ISC were expressed mainly in M2 macrophages, consistent with increased phagocytotic activity induced by the immunoglobulin (Ig)G-Fcγ receptor interaction. In contrast, PSC had two more activated signal pathways related to extracellular matrix (ECM) remodelling. Filamin-A involved in ECM remodelling was expressed aberrantly in injured bile ducts and associated cholangiocarcinomas in PSC, suggesting its possible roles in periductal fibrosis and carcinogenesis in PSC.

CONCLUSIONS

This study suggested crucial roles of B cells and macrophages in ISC, and more dynamic ECM remodelling in PSC.

Immunoglobulin G4-related cholangiopathy: clinical and experimental insights

PURPOSE OF REVIEW

The clinical spectrum of immunoglobulin G4-related disease (IgG4-RD) is diverse and the disease may affect multiple organ systems. The pancreatobiliary tract probably is the clinically most important localization of the disease but diagnosing IgG4-related cholangiopathy (synonym: IgG4-associated cholangitis) or autoimmune pancreatitis is often challenging. This review summarizes the current best practice in diagnosing and treating IgG4-related cholangiopathy and recent advances in our understanding of its cause.

RECENT FINDINGS

The identification of IgG4-switched B-cell and plasma cell populations in patients with IgG4-related cholangiopathy and IgG4-RD and their disappearance upon successful treatment have established the role of these cells in the disorder. Ultimately, these findings may lead to the development of more sensitive diagnostic tests. The observation that many of the predominantly 50-70 years old male patients have been exposed lengthily to occupational hazardous compounds further supports the idea that chronic antigenic stimulation may be a pivotal etiological aspect of the disease. Immunosuppressive treatment remains the therapeutic cornerstone in IgG4-RD.

SUMMARY

Currently available experimental evidence classifies IgG4-RD as an immune-mediated disorder, providing support to the use of immunosuppressants and possibly even more specific therapies targeting the B-cell and plasma cell lineages.