IgG4 cholangiopathy: current concept, diagnosis, and pathogenesis

Cytopenias in Autoimmune Liver Diseases-A Review

Autoimmune liver diseases (AiLDs), including autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC), are immune-mediated conditions associated with significant hepatic and systemic manifestations. Among these, cytopenias-defined as reductions in blood cell counts affecting single or multiple lineages-represent a clinically important, though often under-recognized, complication. Cytopenias in AiLDs arise from diverse mechanisms, including immune-mediated destruction, hypersplenism due to portal hypertension, bone marrow suppression, and nutritional deficiencies. These abnormalities can exacerbate bleeding, infections, or fatigue, complicating the disease course and impacting therapeutic strategies. Immune-mediated cytopenias, such as autoimmune hemolytic anemia (AIHA), immune thrombocytopenic purpura (ITP), and autoimmune neutropenia (AIN), are more frequently associated with AIH, whereas cytopenias in PBC and PSC are largely attributed to hypersplenism. Diagnostic evaluation involves a systematic approach combining clinical history, laboratory testing (e.g., complete blood counts, Coombs tests, and nutritional assessments), imaging studies, and bone marrow evaluation in complex cases. Treatment strategies aim to address the underlying cause of cytopenias, including immunosuppressive therapy for autoimmune mechanisms, beta-blockers or splenectomy for hypersplenism, and supplementation for nutritional deficiencies. Challenges include distinguishing between immune- and hypersplenism-related cytopenias, managing drug-induced cytopenias, and optimizing care in transplant candidates. The recently recognized IgG4-related disease, often mimicking cholestatic AiLDs, adds another layer of complexity, given its association with autoimmune cytopenias and hypersplenism. This review aims to act as a guide for the clinician dealing with patients with AiLDs with respect to the occurrence of cytopenias, with a specific focus on pathophysiology and management of these cytopenias. Furthermore, there need to be enhanced multidisciplinary discussions about those patients between the hematologists and hepatologists, with a maintenance of a high index of suspicion for the rarer causes of cytopenias in AiLDs on the part of the treating physician, and there is a need for further studies to elucidate the mechanisms behind the occurrence of cytopenias in AiLDs.

Characteristics of imaging in hepatic inflammatory pseudotumors: a comparison between IgG4-related and IgG4-unrelated cases

OBJECTIVES

The objective of this study was to examine the imaging features of hepatic inflammatory pseudotumors (IPTs) associated with IgG4-related and IgG4-unrelated conditions and to enhance the approach toward distinguishing between these two types of IPTs.

METHODS

A retrospective study was conducted, involving 20 patients diagnosed with hepatic IPTs. Imaging procedures were conducted within a timeframe of 4 weeks prior to hepatectomy or biopsy. The imaging features were then analyzed and compared using chi-squared analysis.

RESULTS

Seventeen (81.0%) IPTs were located in the hepatic subcapsular area; six (66.7%) IgG4-related IPTs were distributed around the hepatic hilum; and eleven (91.7%) IgG4-unrelated and three (33.3%) IgG4-related IPTs had unclear boundaries. All lesions exhibited similar characteristics in CT scans, T1-weighted imaging (T1WI), T2-weighted imaging (T2WI), and diffusion-weighted imaging (DWI), with the apparent diffusion coefficient (ADC) values slightly higher than the surrounding liver tissue. Delayed hypoenhancement, observed in five cases (55.6%), was exclusively present in IgG4-related IPTs. The remaining IPT lesions displayed progressive enhancement, septal and marginal enhancement, and persistent enhancement. Central enhancement was absent in three IgG4-related IPTs (33.3%) and ten IgG4-unrelated IPTs (83.3%). The duct-penetrating sign was identified in two IgG4-unrelated IPTs (16.7%) and seven IgG4-related IPTs (77.8%). Furthermore, seven patients with IgG4-related IPTs had additional lesions outside the liver.

CONCLUSIONS

IgG4-related lesions are frequently found in the vicinity of the hepatic hilum; they display the duct-penetrating sign and affect other organs as well. Both groups exhibited progressive or persistent contrast enhancement in typical IPT lesions, but delayed hypoenhancement was only observed in the IgG4-related IPT group. IgG4-unrelated IPT lesions often exhibited indistinct boundaries lacking central enhancement.

CRITICAL RELEVANCE STATEMENT

Differences in imaging features differentiate IgG4-related and -unrelated inflammatory pseudotumors (IPT). IgG4-related lesions are frequently near the hepatic hilum, display duct-penetrating sign, and affect other organs. Only the IgG4-related group demonstrated delayed hypoenhancement. IgG4-unrelated IPT lesions often exhibited indistinct boundaries lacking central enhancement.

KEY POINTS

Compared with IgG 4-unrelated IPTs, IgG4-related IPTs show delayed hypoenhancement and affect other organs. IgG4-unrelated IPTs have unclear boundaries and lack central enhancement. Improved IPT diagnostic capabilities can help minimize additional, potentially unnecessary, interventions.

MRI diagnosis of tumor‑like IgG4 masses in bilateral distal ureters: A case report

IgG4 masses in the bilateral distal ureters are rare and frequently misdiagnosed. The present study reported the case of a 55-year-old male patient with IgG4-related disease (IgG4-RD) who had symmetrical soft tissue masses of the bilateral distal ureters found on magnetic resonance imaging (MRI) with a significant increase in the serum levels of IL-6, IgG4 and IgE. Regarding treatment, this patient received prednisone acetate tablets (40 mg/day) and mycophenolate mofetil dispersible tablets (1 g/day). During the follow-up, significant reductions in the levels of IgG4 and IgE were found after 30 days. MRI after 6 months indicated complete disappearance of the masses. The prognosis has been good so far. In clinical practice, it is necessary to consider the possibility of IgG4-RD in cases with soft tissue masses surrounding both ureters and elevated levels of serum IgG4.

A case of hilar biliary cystadenoma with elevated IgG4 levels

Cholangiocytic adenoma in the hilar bile duct is rare, and elevated IgG4 at the same time is extremely rare. This situation has not been reported in the literature. Nonetheless, the current case involved hilar biliary cystadenoma with elevated IgG4 levels. A 66-year-old man presented at this hospital with dark tea-colored urine. Preoperative imaging studies suggested hilar cholangiocarcinoma. This case demonstrates the difficulty of preoperative diagnosis of benign hilar lesions and the rarity of two combined benign lesions. A point of contention is whether this case should be treated with surgery or hormone therapy.

IgG4-Related Sclerosing Cholangitis: Rarely Diagnosed, but not a Rare Disease

IgG4-related sclerosing cholangitis, a biliary manifestation of an IgG4-related disease, belongs to the spectrum of sclerosing cholangiopathies which result in biliary stenosis. It presents with signs of cholestasis and during differential diagnosis it should be distinguished from cholangiocarcinoma or from other forms of sclerosing cholangitis (primary and secondary sclerosing cholangitis). Despite increasing information and recently established diagnostic criteria, IgG4-related sclerosing cholangitis remains underdiagnosed in routine clinical practice. The diagnosis is based on a combination of the clinical picture, laboratory parameters, histological findings, and a cholangiogram. Increased serum IgG4 levels are nonspecific but are indeed a part of the diagnostic criteria proposed by the Japan Biliary Association and the HISORt criteria for IgG4-SC. High serum IgG4 retains clinical utility depending on the magnitude of elevation. Approximately 90% of patients have concomitant autoimmune pancreatitis, while 10% present with isolated biliary involvement only. About 26% of patients have other organ involvement, such as IgG4-related dacryoadenitis/sialadenitis, IgG4-related retroperitoneal fibrosis, or IgG4-related renal lesions. A full-blown histological finding characterized by IgG4-enriched lymphoplasmacytic infiltrates, obliterative phlebitis, and storiform fibrosis is difficult to capture in practice because of its subepithelial localization. However, the histological yield is increased by immunohistochemistry, with evidence of IgG4-positive plasma cells. Based on a cholangiogram, IgG-4 related sclerosing cholangitis is classified into four subtypes according to the localization of stenoses. The first-line treatment is corticosteroids. The aim of the initial treatment is to induce clinical and laboratory remission and cholangiogram normalization. Even though 30% of patients have a recurrent course, in the literature data, there is no consensus on chronic immunosuppressive maintenance therapy. The disease has a good prognosis when diagnosed early.

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.

Intrahepatic bile duct rupture associated with IgG4-related sclerosing cholangitis presenting hepatic inflammatory pseudotumor

A 67-year-old man with a low-grade fever was found to have a 25-mm diameter tumor of the left hepatic umbilical portion. The tumor was accompanied by occlusion of the left portal vein. Positron emission tomography using fluorodeoxyglucose showed that the tumor had abnormally high metabolic activity. Magnetic resonance imaging revealed the left hepatic duct segmental narrowing. There was a mild elevation in serum IgG4 (206 mg/dL). Intrahepatic cholangiocarcinoma was suspected. Instead of planned hepatectomy, the patient was forced to undergo emergency surgery for biliary panperitonitis caused by intrahepatic bile duct rupture. Intraoperative ultrasonography revealed a hypoechoic tumor-like thickened Glissonean sheath and needle biopsy was performed. Histologic examination confirmed fibrous tissue with IgG4-positive plasma cell infiltration without neoplastic proliferation. He was diagnosed with IgG4-related sclerosing cholangitis (IgG4-SC) presenting hepatic inflammatory pseudotumor. After his general condition improved, he underwent left hepatectomy. Macroscopic findings showed extreme fibrosis of the Glissonean sheath of the umbilical portion, and diffuse granular lesion aggregated in the left lateral segment. Microscopic examination confirmed chronic cholangitis and dense portal fibrosis in the umbilical portion and diffuse xanthogranulomatous inflammation. This is the first case report of spontaneous rupture of the intrahepatic bile duct in patient with IgG4-SC.

Cholestatic liver disease: Practice guidelines from the Saudi Association for the Study of Liver diseases and Transplantation

Cholestatic liver diseases (CLDs) are a group of diseases characterized by jaundice and cholestasis as the main presentation with different complications, which have considerable impact on the liver and can lead to end-stage liver disease, cirrhosis, and liver-related complications. In the last few years, tremendous progress has been made in understanding the pathophysiology, diagnosis, and treatment of patients with these conditions. However, several aspects related to the management of CLDs remain deficient and unclear. Due to the lack of recommendations that can help in the management, treatment of those conditions, the Saudi Association for the Study of Liver diseases and Transplantation (SASLT) has created a task force group to develop guidelines related to CLDs management in order to provide a standard of care for patients in need. These guidelines provide general guidance for health care professionals to optimize medical care for patients with CLDs for both adult and pediatric populations, in association with clinical judgments to be considered on a case-by-case basis. These guidelines describe common CLDs in Saudi Arabia, with recommendations on the best approach for diagnosis and management of different diseases based on the Grading of Recommendation Assessment (GRADE), combined with a level of evidence available in the literature.

Differences in Clinical Features and Diagnostic Strategies Between IgG4-Related Autoimmune Cholangitis and Cholangiocarcinoma

IgG4-related autoimmune cholangitis (IgG4-AIC) is often difficult to distinguish from cholangiocarcinoma (CCA). This study aimed to determine a practical clinical strategy for distinguishing between IgG4-AIC and CCA to avoid unnecessary surgical resection. We retrospectively collected and compared the clinicopathological data between IgG4-AIC and CCA patients, including the clinical, serological, and radiological characteristics, to follow up on these patients to investigate the prognosis. Among the 377 patients who received surgical resection for suspecting CCA at the Sun Yat-Sen Memorial Hospital between June 2004 and June 2014, 14 patients were diagnosed as IgG4-AIC through histochemistry after surgery. Immunohistochemistry revealed that IgG4 was up-regulated in the plasma cells of IgG4-AIC tissues in 13 out of 14 patients. The serum CA19-9 level was significantly lower than in the CCA group. Patients with IgG4-AIC can only see slight or no enhancement under the contrast enhancement CT scan, while there are no signs of ring-like or delayed enhancement that is unique to CCA. Thirteen patients were followed up, and the time was 12 to 92 months. Three of them were regularly treated with prednisone after surgery, and original symptoms disappeared. Our study demonstrated that the combination of imaging with serum CA19-9 could improve the preoperative diagnostic value and reduce the rate of unnecessary resection.

Isolated Type Immunoglobulin G4 Sclerosing Cholangitis: The Misdiagnosed Cholangiocarcinoma

Immunoglobulin G4 sclerosing cholangitis (IgG4-SC), firstly described in 2004, is the biliary manifestation of a recently described multisystem immune-mediated disease known as IgG4-related disease. IgG4-SC is a unique and rare type of cholangitis of unknown etiology and its precise prevalence rate is still unclear. It is characterized by bile duct wall thickening and high levels of systemic serum IgG4 plasma cells. Differential diagnoses for IgG4-SC include benign (primary sclerosing cholangitis) as well as malignant (extra-hepatic cholangiocarcinoma) diseases. Discrimination between these entities is very important, due to the fact that they have different biological behaviors and different therapeutic strategies. The rare IgG4-SC subgroup with its puzzling manifestations carries a hefty diagnostic challenge for the treating physicians, and inaccurate diagnosis can lead to unnecessary morbid surgical procedures. With the paucity and relative weakness of available data in the current literature, one needs to carefully review all available parameters. A low threshold of suspicion is required to try and prevent missing IgG4-SC. IgG4-SC is highly responsive to steroid treatment, especially during the early inflammatory phase, while delay in management could lead to fibrosis and organ dysfunction. On the other hand, cholangiocarcinoma is treated by means of surgery and/or chemotherapeutic agents.

The long-term outcomes of patients with immunoglobulin G4-related sclerosing cholangitis: the Mayo Clinic experience

BACKGROUND

The long-term outcomes of immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) are not well known.

METHODS

The outcomes of patients with IgG4-SC at Mayo Clinic (1999-2018) were compared to an age- and gender-matched (1:1 ratio) group of patients with primary sclerosing cholangitis (PSC).

RESULTS

We identified 89 patients with IgG4-SC; median age at diagnosis was 67 years, 81% were males, and the median follow-up was 5.7 years. Seventy-eight patients received prednisone for induction of remission, and 53 received at least one other immunosuppressive agent for maintenance of remission. Of the IgG4-SC group, 10 died (median time from diagnosis until death was 6.5 years): 2 due to cirrhosis, 3 due to cholangiocarcinoma (CCA), and 5 due to non-hepatobiliary causes. Eleven patients in the PSC group underwent liver transplantation, while none did in the IgG4-SC group. The incidence of a hepatobiliary adverse event (cirrhosis or CCA) was 3.4 times greater in the PSC compared to the IgG4-SC group (events per 1000 person-years: 52.6; 95% CI 38-73; vs. 15.6; 95% CI 7-32). The probability of development of a hepatobiliary adverse event within 10 years was 11% in the IgG4-SC compared to 45% in the PSC group (P = 0.0001). The overall survival tended to be higher in the IgG4-SC compared to the PSC group (10-year: 79% vs. 68%, respectively; P = 0.11).

CONCLUSIONS

In a cohort of IgG4-SC patients, 88% of whom were treated with immunosuppressive drugs, the risk of cirrhosis and CCA was significantly lower compared to an age- and gender-matched group with PSC.

Chronic cholangitides: Differential diagnosis and role of MRI

The idiopathic chronic cholangitides comprise a group of hepatobiliary diseases of probable autoimmune origin that are usually asymptomatic in the initial stages and can lead to cirrhosis of the liver. Elevated cholestatic enzymes on blood tests raise suspicion of these entities. Among the idiopathic cholangitides, the most common is primary sclerosing cholangitis, which is associated with inflammatory bowel disease and with an increased incidence of hepatobiliary and digestive tract tumors. It is important to establish the differential diagnosis with IgG4-associated cholangitis, primary biliary cholangitis, and secondary cholangitides, because the therapeutic management is different. Magnetic resonance cholangiopancreatography (MRCP) is the best test to evaluate the intrahepatic and extrahepatic biliary tract, and MRI also provides information about the liver and other abdominal organs. An appropriate MRCP protocol and knowledge of the different findings that are characteristic of each entity are essential to reach the correct diagnosis.

IgG4-related disease with multiple organs involvement was effectively controlled by glucocorticoids: a case report

Immunoglobulin G4 (IgG4) related disease is a rare autoimmune disease involving multiple organs and tissues. A diagnosis of IgG4-related disease (IgG4-RD) is mainly based on serum IgG4 concentration, imaging, pathology, and effective glucocorticoids therapy. In this paper, we report a 53-year-old male with typical signs and symptoms of IgG4-RD successfully treated with glucocorticoids. This patient had experienced bilateral mumps for more than 8 months and intermittent abdominal pain spreading to his lower back for 2 months before his admission. During his hospitalization, based on the characteristic appearance of magnetic resonance imaging (MRI), magnetic resonance cholangiopancreatography (MRCP), and computed tomography with positron emission tomography, a diagnosis of autoimmune pancreatitis (AIP), cholangitis with biliary obstruction, lachrymal adenitis, and submandibular adenitis was made. A high serum IgG4 concentration further supported a diagnosis of IgG4-RD. Then, the treatment was promptly initiated with corticosteroids. MRI, MRCP, and IgG4 concentration were re-examined during his follow up, suggesting that glucocorticoid treatment resulted in a resolution of his disease. The dosage of glucocorticoid had been gradually decreased. Now, he is stable with oral low-dose glucocorticoids. Certainly, long-term follow up of this patient with such a rare disease is very essential to observe the possibility of disease recurrence and glucocorticoids related complications.

Diagnosis and management of IgG4-related disease

IgG subclass 4-related disease (IgG4-RD) is a rare but increasingly recognised fibroinflammatory condition known to affect multiple organs. IgG4-RD is characterised by unique histological features of lymphoplasmacytic infiltration, storiform fibrosis and obliterative phlebitis. In this review we describe the pancreaticobiliary manifestations of IgG4-RD, with particular emphasis on type 1 autoimmune pancreatitis (AIP) and IgG4-related sclerosing cholangitis (IgG4-SC). AIP and IgG4-SC can pose diagnostic challenges to the clinician as they may mimic pancreatic cancer and primary sclerosing cholangitis, respectively. We discuss current knowledge, clinical diagnostic criteria and recent advances and summarise the evidence base for current therapeutic approaches for AIP and IgG4-SC.

Imaging in Autoimmune Pancreatitis and Immunoglobulin G4-Related Disease of the Abdomen

Autoimmune pancreatitis (AIP) is steroid-responsive fibroinflammatory disorder of the pancreas. There are 2 distinct subtypes of AIP, types 1 and 2. Type 1 is associated with systemic immunoglobulin (Ig)G4 disease and may affect multiple organs in the body. Type 2 is confined to the pancreas and shows an association with ulcerative colitis. This article describes the imaging findings of AIP and IgG4 disease in the liver, bile ducts, kidneys, and the retroperitoneal regions. The imaging differentiation of AIP from pancreas cancer is discussed.

A good response to steroid therapy in IgG4-related sclerosing cholangitis: a case report

IgG4-related sclerosing cholangitis is a rare autoimmune liver disease. Biliary tract imaging, serum IgG4 concentration, and histopathological examination are the major diagnostic criteria for IgG4-related sclerosing cholangitis. In this paper, we report a male patient with yellowish skin, in whom classical liver-protection drugs were initially given, but the efficacy was poor. After that, IgG4-related sclerosing cholangitis was diagnosed, and he achieved a good response to steroid therapy.

Successful treatment of acute-on-chronic liver failure and hemolytic anemia with hepato-protective drugs in combination with intravenous ozone without steroids: A case report

Both acute-on-chronic liver failure (ACLF) and autoimmune hemolytic anemia (AIHA) are common causes of jaundice. A co-occurrence of ACLF and AIHA is rare in clinical practice. This report describes a male elderly patient who developed persistently increased levels of total bilirubin and ascites after endoscopic retrograde cholangiopancreatography for the successful treatment of common bile duct stones. Eventually, he was diagnosed with ACLF and AIHA according to current diagnostic criteria. The patient was given conventional hepato-protective drugs, human albumin, and diuretics in combination with immune ozone without steroids, and he responded well. The therapeutic role of immune ozone in this case is also discussed. When immune ozone was given, total bilirubin gradually decreased; however, no change in total bilirubin was observed after immune ozone was stopped. Notably, when immune ozone was re-initiated, total bilirubin decreased again.

A case report of immunoglobulin G4-related sclerosing cholangitis with multiple relapse

RATIONALE

Immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) is classified as a biliary tract manifestation of immunoglobulin G4-related disease (IgG4-RD). Glucocorticoid is the first-line therapy for most patients, but the optimal starting dose, adequate maintaining dose and withdrawal time remain disputable.

PATIENT CONCERNS

An elderly male patient presented to our hospital with neoplasms of the bile duct and pancreas at first visit in December 2011. Further examination revealed bile duct stenosis and obstruction, and elevated serum IgG4 level.

DIAGNOSES

A diagnosis of IgG4-SC was established by examination results and effectiveness of steroid therapy, although IgG4-positive plasma cells were seldom seen in the liver sample.

INTERVENTIONS

Prednisolone was started from 40 mg daily, tapered gradually, and totally withdrawn after 22 months of treatment.

OUTCOMES

A new-onset cholangitis was detected 2 months later. Prednisolone 10 mg daily was administered again. Prednisolone was reduced to 5 mg every other day without consultation with his doctor 1 year ago in May 2017, then he presented to our hospital again with recurrent abdominal pain and jaundice.

LESSONS

IgG4-SC is a protean condition and can be distinguished from primary sclerosing cholangitis, malignancy, and other inflammatory disorders based on 4 clinical criteria. Serum IgG4/IgG1 ratio is a practicable diagnostic algorithm to distinguish PSC from IgG4-SC. The dose and duration of glucocorticoid for treatment should be adjusted according to clinical situations, and proper maintaining dose is essential for a better prognosis.

Hilar cholangiocarcinoma associated with immunoglobulin G4-positive plasma cells and elevated serum immunoglobulin G4 levels

Immunoglobulin G4 (IgG4)‐related disease is a fibroinflammatory systemic disorder with multiorgan involvement. Proximal bile duct involvement results in IgG4‐related sclerosing cholangitis, which is characterized by a lymphoplasmacytic infiltrate with abundant IgG4‐positive plasma cells and fibrosis. Differentiating between cholangiocarcinoma and IgG4‐sclerosing cholangitis can present a diagnostic dilemma. We describe an unusual presentation of a hepatic mass meeting multiple criteria for IgG4‐sclerosing cholangitis but was ultimately found to be cholangiocarcinoma. Several published case reports describe patients with suspected cholangiocarcinoma who are later found to have IgG4‐sclerosing cholangitis, but few reports have demonstrated the reverse. Distinguishing between cholangiocarcinoma and IgG4‐sclerosing cholangitis is challenging, and a high clinical suspicion for cholangiocarcinoma must always be maintained. (Hepatology Communications 2018;2:349‐353)

[Hepatopancreaticobiliary diseases in IgG4-associated autoimmune diseases]

BACKGROUND

IgG4-related diseases are rare systemic multiorgan diseases and can thus affect any organ system. The incidence of diagnosis has significantly increased due to increasing awareness.

OBJECTIVE

In the abdomen the hepatopancreaticobiliary system provides an essential organ system for the expression of IgG4-associated autoimmune diseases. The focus here is autoimmune pancreatitis type 1 but IgG4-associated sclerosing cholangitis and IgG4-associated hepatopathy, which can also occur in combination are less well-known.

METHODS

Various mostly Asiatic, histologically-based diagnostic systems, such as HISORt or international consensus diagnostic criteria (ICDC) are available for the diagnostics of hepatopancreaticobiliary IgG4-related autoimmune diseases, in which imaging techniques playing an increasingly important role.

RESULTS

In addition to generalized organ swelling further morphological and also functional imaging criteria have become increasingly well-known for autoimmune pancreatitis, such as late enhancement or the imaging response to steroid therapy. Magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERP) can provide valuable information for the diagnostics of IgG4-related diseases in the hepatopancreaticobiliary system.

CONCLUSION

IgG4-related autoimmune diseases of the hepatopancreaticobiliary system are a rare group of diseases in which increasing knowledge of the radiological appearance also leads to an increasingly frequency of diagnosis. IgG4-related diseases must be distinguished from non-necrotizing pancreatitis and pancreatic cancer, which is often difficult but has significant therapeutic consequences for the patients.

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.

Development of a scoring system for differentiating IgG4-related sclerosing cholangitis from primary sclerosing cholangitis

BACKGROUND

Recent research has shown that a substantial number of patients with primary sclerosing cholangitis (PSC) can also have elevated serum/tissue IgG4. The aim of our study was to develop a simple scoring system for the discrimination of IgG4-related sclerosing cholangits (IgG4-SC) from PSC.

METHODS

Patients with IgG4-SC (n = 39) and PSC (n = 76) who had intrahepatic/hilar strictures were included. Candidate-differentiating variables included patient age, other organ involvement (OOI), inflammatory bowel disease, serum IgG4, and cholangiographic features. A scoring system was developed on the basis of these variables, and its performance was internally validated using a bootstrapping-based method.

RESULTS

The scoring system in the final model included age (<30 years, 0 points; 30-39 years, 1 point; 40-49 years, 2 points; 50-59 years, 3 points; ≥60 years, 4 points), OOI (no, 0 points; yes, 3 points), and beaded appearance (yes, 0 points; no, 2 points). The patients were classified according to their total score into three categories: 0-4 points, probable PSC; 5-6 points, indicating diagnostic steroid trial; 7-9 points, probable IgG4-SC. The discrimination between IgG4-SC and PSC using the scoring system was excellent (area under the receiver operating characteristic curve, 0.986).

CONCLUSIONS

A reliable differentiation of IgG4-SC from PSC can be made using the scoring system presented here. We suggest the diagnosis of IgG4-SC at a cutoff of 7 points or higher and the indication of diagnostic steroid trial at 5 or 6 points. External validation of our scoring system is warranted.

IgG4-related sclerosing cholangitis overlapping with autoimmune hepatitis: Report of a case

BACKGROUND

IgG4-related sclerosing cholangitis (IgG4-SC) is the biliary manifestation of IgG4-related disease (IgG4-RD) but the presence of IgG4-SC in the porta hepatis is difficult to differentiate from hilar cholangiocarcinoma (HCCA). IgG4-related autoimmune hepatitis (IgG4-related AIH) is extremely rare and it is not fully clear whether IgG4-related AIH is a hepatic manifestation of IgG4-RD or a subtype of AIH.

CASE PRESENTATION

We present a rare case of a 52-year-old male who was admitted with obstructive jaundice and itchy skin. He primarily presented a severe bile duct stricture in the porta hepatis and an elevated serum level of carbohydrate antigen 19-9 (CA19-9) mimicking HCCA. The patient underwent a surgical resection of the left hepatic lobular and cholecyst as well as common bile duct with a right hepatico-jejunostomy. He was finally diagnosed as IgG4-SC accompanied with IgG4-related AIH by immunohistochemistry, but he lacked conventional autoantibodies. The patient responded well to steroid therapy and remains healthy with no signs of recurrence at six-month follow-up.

CONCLUSION

This is the first case report that hepatic portal IgG4-SC overlapping with IgG4-related AIH without the presence of conventional autoantibodies. Additionally, we suggest that IgG4-RD should be always considered in case of a bile duct stricture in the porta hepatis to avoid unnecessary surgical operation.

Imaging of autoimmune biliary disease

Autoimmune biliary diseases are poorly understood but important to recognize. Initially, autoimmune biliary diseases are asymptomatic but may lead to progressive cholestasis with associated ductopenia, portal hypertension, cirrhosis, and eventually liver failure. The three main forms of autoimmune biliary disease are primary biliary cirrhosis, primary sclerosing cholangitis, and IgG4-associated cholangitis. Although some overlap may occur between the three main autoimmune diseases of the bile ducts, each disease typically affects a distinct demographic group and requires a disease-specific diagnostic workup. For all the autoimmune biliary diseases, imaging provides a means to monitor disease progression, assess for complications, and screen for the development of hepatobiliary malignancies that are known to affect patients with these diseases. Imaging is also useful to suggest or corroborate the diagnosis of primary sclerosing cholangitis and IgG4-associated cholangitis. We review the current literature and emphasize radiological findings and considerations for these autoimmune diseases of the bile ducts.

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.

Differential Diagnosis of Immunoglobulin G4-associated Cholangitis From Cholangiocarcinoma

BACKGROUND AND AIM

Immunoglobulin G4-associated cholangitis (IAC) shares many similar symptoms with cholangiocarcinoma (CCA). However, the treatment and the prognosis are substantially different. This study aimed to identify the important markers for the differential diagnosis of these 2 diseases.

METHODS

Thirty IAC patients and 275 CCA patients were reviewed retrospectively for their clinical symptoms, serological tests, and imaging characteristics. Posttreatment responses were also studied.

RESULTS

IgG4 had 100% specificity for IAC at a cutoff of 6 times the upper normal limit. IAC patients had a significantly higher incidence of weight loss (P=0.025) and a higher level of weight loss (P=0.008) than CCA patients. The positive rates of biological markers CA199, CA242, and CEA in CCA and IAC were 81.5% versus 42.9%, 45.5% versus 4.5%, and 29.2% versus 7.1%, respectively. Levels of these tumor markers in CCA were significantly higher than in IAC (P<0.05). The thickened wall [17/18 (94.4%) vs. 3/10 (30%), P=0.001] and the occupying lesion on the bile duct [1/18 (5.6%) vs. 8/10 (80%), P<0.001] were found to be significantly different in IAC and CCA, respectively, by endoscopic ultrasonography. Autoimmune pancreatitis was the most frequently observed comorbidity of IAC (25/30). All IAC patients respond positively to steroid treatment.

CONCLUSIONS

Increased tumor markers, 6-fold higher levels of serum IgG4, and other organs' involvement could be the reference factors for a differential diagnosis of IAC and CCA. Endoscopic ultrasonography might be an effective imaging tool for diagnosis, although clinical signs and symptoms of IAC and CCA are similar. Experimental steroid treatment can be useful in the diagnosis for certain difficult cases.

Adult bile duct strictures: differentiating benign biliary stenosis from cholangiocarcinoma

Biliary epithelial cells preferentially respond to various insults under chronic pathological conditions leading to reactively atypical changes, hyperplasia, or the development of biliary neoplasms (such as biliary intraepithelial neoplasia, intraductal papillary neoplasm of the bile duct, and cholangiocarcinoma). Moreover, benign biliary strictures can be caused by a variety of disorders (such as IgG4-related sclerosing cholangitis, eosinophilic cholangitis, and follicular cholangitis) and often mimic malignancies, despite their benign nature. In addition, primary sclerosing cholangitis is a well-characterized precursor lesion of cholangiocarcinoma and many other chronic inflammatory disorders increase the risk of malignancies. Because of these factors and the changes in biliary epithelial cells, biliary strictures frequently pose a diagnostic challenge. Although the ability to differentiate neoplastic from non-neoplastic biliary strictures has markedly progressed with the advance in radiological modalities, brush cytology and bile duct biopsy examination remains effective. However, no single modality is adequate to diagnose benign biliary strictures because of the low sensitivity. Therefore, understanding the underlying causes by compiling the entire clinical, laboratory, and imaging data; considering the under-recognized causes; and collaborating between experts in various fields including cytopathologists with multiple approaches is necessary to achieve an accurate diagnosis.

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.

Immunoglobulin G4-associated autoimmune hepatitis may be found in Western countries

BACKGROUND

Immunoglobulin G4-related disease is a multi-systemic autoimmune disease. The sole involvement of the liver has been recently reported in Japanese patients and named "immunoglobulin G4-associated autoimmune hepatitis".

AIM

To examine the baseline and the 2-year follow-up characteristics of non-Asian patients with immunoglobulin G4-associated autoimmune hepatitis compared to patients with classical autoimmune hepatitis.

METHODS

This was a retrospective study of patients who had undergone liver biopsy between March 2009 and January 2012 before starting any treatment. All patients were treated according to the guidelines. Immunoglobulin G4-associated autoimmune hepatitis was diagnosed according to Umemura's histological definition: at least 10 positive immunoglobulin G4-plasma cells per high power field.

RESULTS

Among 28 enrolled patients (males 39%, median age 54 years): 7 had immunoglobulin G4-associated autoimmune hepatitis (25%) and 21 had classical hepatitis; fibrosis and activity stages were F1: 57%, F2: 11%, F3: 11%, F4: 21% and A1: 18%, A2: 39%, A3: 43%. Alanine aminotransferase (ALT) activity and serum immunoglobulin G levels were similar in the two groups at baseline and at 2 years. Complete biochemical response (normal ALT) was similar in immunoglobulin G4-associated autoimmune hepatitis and classical hepatitis (67% vs. 59% at 2 years, p=0.74).

CONCLUSION

Immunoglobulin G4-associated autoimmune hepatitis has been observed in Western patients and seems to evolve in a similar manner to classical hepatitis.

Biliary strictures and masses: an expanded differential diagnosis

Biliary strictures and masses are commonly a result of cholangiocarcinoma. However, there are several congenital, infectious, inflammatory, autoimmune, iatrogenic, and neoplastic etiologies that should also be considered in the differential diagnosis. Knowledge of the key imaging and clinical findings will aid in facilitating the diagnosis and treatment.

"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.

Diagnosing Biliary Malignancy

The most common malignant causes of biliary strictures are pancreatic cancer and cholangiocarcinoma. Differentiating between malignant and benign causes of biliary strictures has remained a clinical challenge. Endoscopic retrograde cholangiopancreatography (ERCP) remains the mainstay and first-line method of tissue diagnosis but has a poor diagnostic yield. This article reviews the causes of biliary strictures, the initial clinical evaluation of biliary obstruction, the diagnostic yield of ERCP-based sampling methods, the role of newer tools in the armamentarium for evaluating strictures, and ways to address the ongoing challenge of stricture evaluation in patients with primary sclerosing cholangitis.

Hepatobiliary IgG4 Cholangiopathy: Case Series and Literature Review

IgG4 cholangiopathy is a recently described distinctive type of hepatobiliary manifestation of IgG4-related disease. This is often misdiagnosed as a malignancy of the hepatobiliary system on clinical presentation and imaging. Accurate diagnosis is crucial for appropriate management. Histopathology provides crucial information and is characterized by IgG4-positive lymphoplasmacytic infiltration with storiform fibrosis and obliterative phlebitis. We present the clinicopathological spectrum of a retrospective series of 6 cases of IgG4 cholangiopathy that clinically masqueraded as hepatobiliary malignancies.

Elevated IgG4 in patient circulation is associated with the risk of disease progression in melanoma

Emerging evidence suggests pathological and immunoregulatory functions for IgG4 antibodies and IgG4⁺ B cells in inflammatory diseases and malignancies. We previously reported that IgG4 antibodies restrict activation of immune effector cell functions and impair humoral responses in melanoma. Here, we investigate IgG4 as a predictor of risk for disease progression in a study of human sera (n = 271: 167 melanoma patients; 104 healthy volunteers) and peripheral blood B cells (n = 71: 47 melanoma patients; 24 healthy volunteers). IgG4 (IgG4/IgG_total) serum levels were elevated in melanoma. High relative IgG4 levels negatively correlated with progression-free survival (PFS) and overall survival. In early stage (I-II) disease, serum IgG4 was independently negatively prognostic for progression-free survival, as was elevation of IgG4⁺ circulating B cells (CD45⁺CD22⁺CD19⁺CD3^-CD14^-). In human tissues (n = 256; 108 cutaneous melanomas; 56 involved lymph nodes; 60 distant metastases; 32 normal skin samples) IgG4⁺ cell infiltrates were found in 42.6% of melanomas, 21.4% of involved lymph nodes and 30% of metastases, suggesting inflammatory conditions that favor IgG4 at the peripheral and local levels. Consistent with emerging evidence for an immunosuppressive role for IgG4, these findings indicate association of elevated IgG4 with disease progression and less favorable clinical outcomes. Characterizing immunoglobulin and other humoral immune profiles in melanoma might identify valuable prognostic tools for patient stratification and in the future lead to more effective treatments less prone to tumor-induced blockade mechanisms.

Rare case of Helicobacter pylori-positive multiorgan IgG4-related disease and gastric cancer

A 61-year-old male from Northeast China presented with a 2-mo history of abdominal distension, pruritus and jaundice. Laboratory testing revealed an elevated serum IgG4 level. A computed tomography scan showed a typical feature of autoimmune pancreatitis (AIP) and cholecystocholangitis. Early gastric cancer was incidentally discovered when endoscopic untrasound-guided fine needle aspiration (EUS-FNA) of the pancreas was carried out. The patient underwent radical subtotal gastrectomy for gastric cancer combined with cholecystectomy. Helicobacter pylori (H. pylori) and IgG4-positive plasmacytes were detected in gastric cancer tissue, pancreatic EUS-FNA sample and resected gallbladder specimen by immunohistochemistry. The patient was diagnosed with H. pylori-positive IgG4-related AIP and sclerosing cholecystocholangitis as well as H. pylori-positive gastric cancer. He responded well to steroid therapy and remains healthy with no signs of recurrence at one year follow-up. We speculate that H. pylori might act as a trigger via direct or indirect action in the initiation of onset of gastric cancer and multiorgan IgG4-related disease.

IgG4-related autoimmune diseases: Polymorphous presentation complicates diagnosis and treatment

BACKGROUND

IgG4-associated autoimmune diseases are systemic diseases affecting multiple organs of the body. Autoimmune pancreatitis, with a prevalence of 2.2 per 100,000 people, is one such disease. Because these multi-organ diseases present in highly variable ways, they were long thought just to affect individual organ systems. This only underscores the importance of familiarity with these diseases for routine clinical practice.

METHODS

This review is based on pertinent articles retrieved by a selective search in PubMed, and on the published conclusions of international consensus conferences.

RESULTS

The current scientific understanding of this group of diseases is based largely on case reports and small case series; there have not been any randomized controlled trials (RCTs) to date. Any organ system can be affected, including (for example) the biliary pathways, salivary glands, kidneys, lymph nodes, thyroid gland, and blood vessels. Macroscopically, these diseases cause diffuse organ swelling and the formation of pseudotumorous masses. Histopathologically, they are characterized by a lymphoplasmacytic infiltrate with IgG4-positive plasma cells, which leads via an autoimmune mechanism to the typical histologic findings--storiform fibrosis ("storiform" = whorled, like a straw mat) and obliterative, i.e., vessel-occluding, phlebitis. A mixed Th1 and Th2 immune response seems to play an important role in pathogenesis, while the role of IgG4 antibodies, which are not pathogenic in themselves, is still unclear. Glucocorticoid treatment leads to remission in 98% of cases and is usually continued for 12 months as maintenance therapy. Most patients undergo remission even if untreated. Steroid-resistant disease can be treated with immune modulators.

CONCLUSION

IgG4-associated autoimmune diseases are becoming more common, but adequate, systematically obtained data are now available only from certain Asian countries. Interdisciplinary collaboration is a prerequisite to proper diagnosis and treatment. Treatment algorithms and RCTs are needed to point the way to organ-specific treatment in the future.