Variant and Specific Forms of Autoimmune Cholestatic Liver Diseases

CT and MR imaging of primary biliary cholangitis: a pictorial review

Primary biliary cholangitis (PBC) is a rare chronic autoimmune-mediated cholestatic liver disease involving medium and small bile ducts that can lead to liver fibrosis and cirrhosis. To date, the pathogenesis of PBC remains elusive, and there is currently no curative medical treatment. Computed tomography (CT) and magnetic resonance (MR) imaging, as common technical tools that allow non-invasive monitoring of liver tissue in vivo, play crucial roles in the diagnosis, staging, and prognosis prediction in PBC by enabling assessment of abnormalities in liver morphology and parenchyma, irregular configuration of bile ducts, lymphadenopathy, portal hypertension, and complications of cirrhosis. Moreover, CT and MRI can be used to monitor the disease progression after treatment of PBC (e.g. the onset of cirrhotic decompensation or HCC) to guide the clinical decisions for liver transplantation. With the optimization of imaging technology, magnetic resonance elastography (MRE) offers additional information on liver stiffness, allows for the identification of early cirrhosis in PBC and provides a basis for predicting prognosis. Gadoxetic acid-enhanced MRI enables the assessment of liver function in patients with PBC. The purpose of this review is to detail and illustrate the definition, pathological basis, and clinical importance of CT and MRI features of PBC to help radiologists and clinicians enhance their understanding of PBC.Critical Relevance StatementCharacteristic CT and MR imaging manifestations of primary biliary cholangitis may reflect the course of the disease and provide information associated with histological grading and altered cellular function.Key points• Imaging has become highly useful for differentiating PBC from other diseases.• Key pathological alterations of PBC can be captured by CT and MRI.• Characteristic manifestations provide information associated with histological grade and cellular function.• Despite this, the CT or MRI features of PBC are not specific.

Prevalence and significance of antimitochondrial antibodies in autoimmune hepatitis (AIH): Results from a large multicentre study of the International AIH Group

BACKGROUND & AIMS

Antimitochondrial antibodies (AMA) are specific markers for the diagnosis of primary biliary cholangitis (PBC) but can also be found occasionally in patients with autoimmune hepatitis (AIH). The present large multicentre cohort study assessed the prevalence and significance of AMA in AIH-patients.

METHODS

123 AMA-positive AIH-patients were investigated and compared with 711 age-matched AMA-negative AIH-patients and 69 patients with AIH/PBC variant.

RESULTS

AMA prevalence in AIH-patients was 5.1% (range: 1.2%-11.8%). AMA-positivity was associated with female sex (p = 0.031) in AMA-positive AIH-patients but not with liver biochemistry, bile duct injury on liver biopsy, disease severity at baseline and response to treatment compared to AMA-negative AIH-patients. Comparing AMA-positive AIH-patients to those with AIH/PBC variant, there was no difference in disease severity. Regarding liver histology, AIH/PBC variant patients were characterized by the presence of at least one feature of bile duct damage (p<0.001). Response to immunosuppressive treatment was similar among groups. From AMA-positive AIH patients only those with evidence of non-specific bile duct injury had higher risk to progress to cirrhosis (HR=4.314, 95%CI: 2.348-7.928; p<0.001). During follow-up, AMA-positive AIH-patients had higher risk to develop histological bile duct injury (HR 4.654, 95%CI 1.829-11.840; p = 0.001).

CONCLUSIONS

AMA presence is relatively common among AIH-patients, but their clinical significance seems important only when they co-exist with non-specific bile duct injury at the histological level. Therefore, a careful evaluation of liver biopsy seems of utmost importance in these patients.

Increased sensitivity of gp210 autoantibody detection using a newly designed gp210 antigen

OBJECTIVES

The detection of autoantibody to glycoprotein 210 (gp210 Ab) against a 15 amino-acid peptide epitope by enzyme-linked immunosorbent assay (ELISA) has been widely used in the diagnosis of primary biliary cholangitis (PBC). However, this small peptide antigen presents spatial limitations for antibody access, which reduces the sensitivity of autoantibody detection. A recombinant gp210 antigen was constructed for increased sensitivity in antibody detection is described here.

METHODS

The gp210 C terminal 18 amino acid coding sequence was ligated to the modified C-terminal 108 amino acid coding sequence of human serum albumin (mHSA108) and produced as a recombinant gp210 antigen mHSA108-gp210-C18. Measurements of gp210 Ab using the gp210 C-terminal 25 amino acid peptide (gp210-C25) and mHSA108-gp210-C18 by in-house ELISA were compared. ELISAs with mHSA108-gp210-C18 and commercial INOVA kit for gp210 Ab detection were also compared in PBC patients and healthy controls. The correlation between the two assays was analyzed and their efficiency in diagnosing was compared.

RESULTS

Of 86 PBC samples, 35 (40.70%) and 44 (52.33%) positive samples were detected for anti-gp210 Ab using gp210-C25 and mHSA108-gp210-C18, respectively. Of 252 samples from PBC, 114 (45.24%) were positive for mHSA108-gp210-C18 ELISA whereas 94 (37.3%) for commercial ELISA (INOVA). All positive samples detected with commercial ELISA kit were also tested positive in mHSA108-gp210-C18 ELISA. Among 374 patients with other autoimmune diseases, anti-gp210 Ab were detected by mHSA108-gp210-C18 ELISA in 0.95% systemic lupus erythematosus (SLE) patients (2/210), 13.04% rheumatoid arthritis (RA) patients (13/97), and 1.47% of Sjögren's Syndrome (SS) patients (1/67).

CONCLUSIONS

Compared to the gp210 peptide antigen, the sensitivity of the ELISA system using mHSA108-gp210-C18 antigen was improved. The novel gp210 antigen could be useful for screening patients known to be at increased risk of developing PBC.

Autoimmune biliary diseases: primary biliary cholangitis and primary sclerosing cholangitis

Autoimmune cholestatic liver diseases are rare hepato-biliary disorders characterized by a progressive, inflammatory destruction of bile ducts. Primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are the main autoimmune cholestatic liver diseases. Both may evolve into secondary biliary cirrhosis and its complications. Therapeutic options are limited and liver transplantation remains the only definitive treatment for PBC and PSC.

Most PBC and PSC patients have a typical presentation, which does not require liver biopsy. However, in routine clinical practice, important variants or specific subgroups that benefit from liver biopsy for proper management may be observed. Herein, we provide a general overview of clinical and pathological characteristic of PBC and PSC, highlighting the most important features for routine diagnostic practice.

Promyelocytic Leukemia Antigen Expression: a Histological Marker for Primary Biliary Cholangitis Diagnosis?

Background and Objectives

Distinguishing primary biliary cholangitis (PBC) from other cholestatic diseases at the histological level could be assisted by new methods, such as immunohistochemical staining of specific antigens.

Methods

We evaluated whether the detection of promyelocytic leukemia protein (PML) can serve as a specific and sensitive marker for PBC diagnosis. Liver biopsies from 26 PBC patients, 20 primary sclerosing cholangitis (PSC), 37 viral hepatitis, 11 non-alcoholic steatohepatitis (NASH) and 5 normal patients were investigated after immunostaining with the anti-PML monoclonal PG-M3, IgG1 antibody.

Results

Immunoreactivity in bile ducts was expressed by the PML-score (quotient of positive ducts to the total number of portal tracts multiplied by 2). PML-score was higher in PBC as compared to controls (P < 0.001). Using a cutoff of 0.18, PML-score proved highly sensitive (84.6%) and specific (89.7%) for confirming PBC as compared to only 5% of PSC, 9.1% of NASH and 13.5% of viral hepatitis patients (P < 0.001). Irrespective of the underlying disease, patients with PML-score > 0.18 were older (P = 0.007), more often females (P < 0.001) with higher ALP (P < 0.001), γ-GT (P = 0.001) and IgM (P < 0.001) compared to the patients with PML-score < 0.18.

Conclusions

We postulate that a simple PML immunohistochemical test could be sufficient for histopathological discrimination of PBC in problematic cases of undefined cholestatic disorders, including small-duct PSC and AMA-negative PBC cases.

Current Trends and Characteristics of Hepatocellular Carcinoma in Patients with Autoimmune Liver Diseases

Hepatocellular carcinoma (HCC), the commonest among liver cancers, is one of the leading causes of mortality among malignancies worldwide. Several reports demonstrate autoimmune liver diseases (AILDs), including autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC) to confer increased risk of hepatobiliary malignancies, albeit at lower frequencies compared to other liver diseases. Several parameters have been recognized as risk factors for HCC development in AIH and PBC, including demographics such as older age and male sex, clinical features, the most decisive being cirrhosis and other co-existing factors, such as alcohol consumption. Moreover, biochemical activity and treatment response have been increasingly recognized as prognostic factors for HCC development in AIH and PBC. As available treatment modalities are effective only when HCC diagnosis is established early, surveillance has been proven essential for HCC prognosis. Considering that the risk for HCC is not uniform between and within disease groups, refinement of screening strategies according to prevailing demographic, clinical, and molecular risk factors is mandated in AILDs patients, as personalized HCC risk prediction will offer significant advantage in patients at high and/or medium risk. Furthermore, future investigations should draw attention to whether modification of immunosuppression could benefit AIH patients after HCC diagnosis.

Alcoholic liver disease and autoimmune hepatitis: Sometimes a closer look under the surface is needed

AIMS

Differential diagnosis of autoimmune hepatitis (AIH) incorporates various liver diseases, including alcoholic liver disease (ALD). We report on clinical, laboratory and outcome characteristics of AIH patients who were initially referred as ALD based on increased alcohol consumption (AIH/ALD).

METHODS

From 2000-2019, we retrospectively identified 12 AIH/ALD patients [9 males, age: 61 (30-73) years] in our prospective data base of 317 AIH patients.

RESULTS

AIH diagnosis was based on aminotransferases elevation in 10 patients, high IgG in 8, compatible autoantibody profile in all and typical/compatible histology in all 9 with available biopsy. There were no significant differences of baseline demographics, presentation, cirrhosis at diagnosis, response to treatment and simplified score compared to 45 age- and sex-matched AIH patients without alcohol consumption and 44 age- and sex-matched ALD patients. However, the AIH/ALD cohort was characterized by more frequent progression to cirrhosis, higher liver-related deaths and overall mortality compared to AIH, though similar to the ALD group. AST/ALT ratio>1 seems to bear a good positive (0.84) and negative predictive value (0.88) for ALD and AIH diagnosis, respectively, but cannot help in discriminating the AIH/ALD variant.

CONCLUSIONS

AIH should not be forgotten in patients with alcohol use when clinical and laboratory features hint towards the diagnosis of AIH/ALD variant as this group seems to have worse outcome compared to those with AIH alone suggesting the need for closer follow-up and surveillance. Reliable autoantibody testing and cautious interpretation of liver histology appear mandatory for AIH diagnosis in these difficult to diagnose cases.

Epigenetic Modifications in Generalized Autoimmune Epithelitis: Sjögren's Syndrome and Primary Biliary Cholangitis

Sjögren's syndrome (SjS) and primary biliary cholangitis (PBC) can be classified as a model of generalized autoimmune epithelitis based on their frequent coexistence in clinical practice and the highly specific immune mediated injury of target epithelial cells. Both of these autoimmune diseases are characterized by female predominance, highly specific circulating autoantibodies, and immune-mediated destruction of the salivary and lachrymal glands and the biliary epithelial cells, respectively. Although the genetic predisposition has been well described for both diseases, genetic studies have failed to completely elucidate their pathogenesis. The recent integration of epigenetic data, analyzing the different cellular partners, opens new perspectives and allows for better understanding of these complex and still incurable diseases. Epigenetic studies on SjS have elucidated the role of DNA methylation alterations in disease pathogenesis, while epigenetic changes that influence expression of genes on the X chromosome have been implicated in the geo-variability and occurrence of PBC. The aim of this review is to describe the advances in epigenetics in the field of autoimmune epithelitis as well as to highlight how epigenetic changes could contribute to better understanding of disease pathogenesis and progression. These advances could yield insights on novel therapeutic interventions.