Autoimmune hepatitis: a review

Astaxanthin Alleviates Autoimmune Hepatitis by Modulating CD8+ T Cells: Insights From Mass Cytometry and Single-Cell RNA Sequencing Analyses

Astaxanthin (ASX) is an oxygen-containing non-vitamin A carotenoid pigment. However, the role of ASX in autoimmune hepatitis (AIH) remains unclear. In this study, a mouse model of AIH is established induced by concanavalin A (ConA). Mass cytometry and single-cell RNA sequencing (scRNA-seq) are used to analyze the potential role of ASX in regulating the immune microenvironment of AIH. ASX treatment effectively alleviated liver damage induced by ConA and downregulated pro-inflammatory cytokines production in mice. Mass cytometry and scRNA-seq analyses revealed a significant increase in the number of CD8+ T cells following ASX treatment. Functional markers of CD8+ T cells, such as CD69, MHC II, and PD-1, are significantly downregulated. Additionally, specific CD8+ T cell subclusters (subclusters 4, 13, 24, and 27) are identified, each displaying distinct changes in marker gene expression after ASX treatment. This finding suggests a modulation of CD8+ T cell function by ASX. Finally, the key transcription factors for four subclusters of CD8+ T cells are predicted and constructed a cell-to-cell communication network based on receptor-ligand interactions probability. In conclusion, ASX holds the potential to ameliorate liver damage by regulating the number and function of CD8+ T cells.

Hepatic expression of tumor necrosis factor-α and evaluation of MAPK-p38 and NFκB signaling pathways in autoimmune hepatitis

OBJECTIVES

Autoimmune hepatitis (AIH) is a necroinflammatory disease that occurs when genetically susceptible individuals are exposed to an environmental trigger. It is a rare disease, and its epidemiological aspects are nearly unknown in Northeast Brazil. In the literature, the activation of components of the inflammatory cascade pathways, including interleukins such as TNF-α and signaling factors like MAPK-p38 and NFκB, in the pathogenesis of AIH is well described in animal models. This study evaluated, for the first time, the immunostaining of TNF-α, MAPK-p38, and NFκB in immunohistochemical analysis of liver biopsies from AIH patients. The activation of the MAPK-p38 pathway was also studied through immunoassay analysis in the peripheral blood of AIH patients.

METHODS AND RESULTS

Data from medical records of 25 AIH patients were analyzed. Histological and immunohistochemical analysis of liver tissue obtained from biopsies was performed to detect NFκB, MAPK-p38, and TNF-α. Immunoassay analysis of the MAPK-p38 pathway was performed in peripheral blood from 18 AIH patients and 8 healthy volunteers. Medical record analysis showed an average age of 33.3 years, with a female predominance in a ratio of 7.3:1. Concomitance with other autoimmune diseases was observed in 36 % of patients, with thyroid disorders being the most prominent among them, and an 8 % indication for liver transplantation. In the evaluation of autoantibodies, ANA was detected in 52 %, followed by SMA at 20 %, and Anti-LKM-1 at 16 %. Liver biopsy findings were like the global literature, with interface hepatitis and lymphoplasmacytic infiltration observed. Immunohistochemical analysis showed immunostaining for NFκB, MAPK-p38, and TNF-α, corroborating the inflammatory and immunological characteristics of the disease. Immunoassay analysis in peripheral blood confirmed the activation of the MAPK-p38 signaling pathway, with a statistically significant difference between AIH patients and healthy controls.

CONCLUSIONS

The epidemiological and histological findings of AIH in this study in Northeast Brazil were like global population data. Immunohistochemical analysis of liver tissue and immunoassay analysis in peripheral blood confirmed the activation of TNF-α and the NFκB and MAPK-p38 signaling pathways in AIH patients.

Case study: autoimmune hepatitis with cirrhosis and pancytopenia since 7 weeks' gestation

Objectives

Autoimmune hepatitis (AIH) is a chronic inflammatory disease of unknown etiology and AIH in pregnancy is associated with many adverse maternal and fetal outcomes. The purpose of this report is to share insight into management of AIH-induced pancytopenia unresponsive to steroids and transfusions.

Case presentation

A 29-year-old G4P0121 female with history of spontaneous bacterial peritonitis (SBP) and severe pancytopenia secondary to AIH was found to be incidentally pregnant at 7 weeks gestation. Despite multiple blood transfusions and steroids, her pancytopenia was unresponsive to therapy. At 33 weeks, she underwent primary cesarean section for persistent category II fetal heart tracing and delivered a viable infant. Delivery was complicated by hemorrhage requiring multiple blood products. Postpartum course was complicated by sepsis secondary to urinary tract infection, and decompensated cirrhosis with hepatic encephalopathy and coagulopathy. Both fetus and mother have recovered well 3 months post-delivery.

Conclusions

This case highlights the challenges in management of AIH in pregnancy, particularly the difficulty in treating severe unresponsive pancytopenia as well as balancing the need for immunosuppression with the increased risk of infection that may lead to sequelae such as SBP and puerperal sepsis.

TPN10475 alleviates concanavalin A-induced autoimmune hepatitis by limiting T cell development and function through inhibition of PI3K-AKT pathway

Autoimmune hepatitis (AIH) is an inflammatory liver disease in which the autoimmune system instigates an attack on the liver, causing inflammation and liver injury, and its incidence has increased worldwide in recent years. The mouse model of acute hepatitis established by concanavalin A (Con A) is a typical and recognized mouse model for the study of T-cell-dependent liver injury. In this study, we aimed to investigate whether the artemisinin derivative TPN10475 could alleviate AIH and its possible mechanisms. TPN10475 effectively inhibited lymphocyte proliferation and IFN-γ+ T cells production in vitro, alleviated liver injury by decreasing infiltrating inflammatory T cells producing IFN-γ in the liver and peripheral immune tissues, and demonstrated that TPN10475 weakened the activation and function of T cells by inhibiting PI3K-AKT signaling pathway. These results suggested that TPN10475 may be a potential drug for the treatment of AIH, and the inhibition of PI3K-AKT signaling pathway may provide new ideas for the study of the pathogenesis of AIH.

Multiple Dimensions of using Mesenchymal Stem Cells for Treating Liver Diseases: From Bench to Beside

Liver diseases impose a huge burden worldwide. Although hepatocyte transplantation has long been considered as a potential strategy for treating liver diseases, its clinical implementation has created some obvious limitations. As an alternative strategy, cell therapy, particularly mesenchymal stem cell (MSC) transplantation, is widely used in treating different liver diseases, including acute liver disease, acute-on-chronic liver failure, hepatitis B/C virus, autoimmune hepatitis, nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, alcoholic liver disease, liver fibrosis, liver cirrhosis, and hepatocellular carcinoma. Here, we summarize the status of MSC transplantation in treating liver diseases, focusing on the therapeutic mechanisms, including differentiation into hepatocyte-like cells, immunomodulating function with a variety of immune cells, paracrine effects via the secretion of various cytokines and extracellular vesicles, and facilitation of homing and engraftment. Some improved perspectives and current challenges are also addressed. In summary, MSCs have great potential in the treatment of liver diseases based on their multi-faceted characteristics, and more accurate mechanisms and novel therapeutic strategies stemming from MSCs will facilitate clinical practice.

New-onset and relapsed liver diseases following COVID-19 vaccination: a systematic review

BACKGROUND

Liver diseases post-COVID-19 vaccination is extremely rare but can occur. A growing body of evidence has indicated that portal vein thrombosis, autoimmune hepatitis, raised liver enzymes and liver injuries, etc., may be potential consequence of COVID-19 vaccines.

OBJECTIVES

To describe the results of a systematic review for new-onset and relapsed liver disease following COVID-19 vaccination.

METHODS

For this systematic review, we searched Proquest, Medline, Embase, PubMed, CINAHL, Wiley online library, Scopus and Nature through the Preferred Reporting Items for Systematic Reviews and Meta Analyses PRISMA guideline for studies on the incidence of new onset or relapsed liver diseases post-COVID-19 vaccination, published from December 1, 2020 to July 31, 2022, with English language restriction.

RESULTS

Two hundred seventy-five cases from one hundred and eighteen articles were included in the qualitative synthesis of this systematic review. Autoimmune hepatitis (138 cases) was the most frequent pathology observed post-COVID-19 vaccination, followed by portal vein thrombosis (52 cases), raised liver enzymes (26 cases) and liver injury (21 cases). Other cases include splanchnic vein thrombosis, acute cellular rejection of the liver, jaundice, hepatomegaly, acute hepatic failure and hepatic porphyria. Mortality was reported in any of the included cases for acute hepatic failure (n = 4, 50%), portal vein thrombosis (n = 25, 48.1%), splanchnic vein thrombosis (n = 6, 42.8%), jaundice (n = 1, 12.5%), raised liver enzymes (n = 2, 7.7%), and autoimmune hepatitis (n = 3, 2.2%). Most patients were easily treated without any serious complications, recovered and did not require long-term hepatic therapy.

CONCLUSION

Reported evidence of liver diseases post-COIVD-19 vaccination should not discourage vaccination against this worldwide pandemic. The number of reported cases is relatively very small in relation to the hundreds of millions of vaccinations that have occurred and the protective benefits offered by COVID-19 vaccination far outweigh the risks.

In Search for the Missing Link in APECED-like Conditions: Analysis of the AIRE Gene in a Series of 48 Patients

Autoimmune diseases are a heterogeneous group of disorders of the immune system. They can cluster in the same individual, revealing various preferential associations for polyendocrine autoimmune syndromes. Clinical observation, together with advances in genetics and the understanding of pathophysiological processes, has further highlighted that autoimmunity can be associated with immunodeficiency; autoimmunity may even be the first primary immunodeficiency manifestation. Analysis of susceptibility genes for the development of these complex phenotypes is a fundamental issue. In this manuscript, we revised the clinical and immunologic features and the presence of AIRE gene variations in a cohort of 48 patients affected by high polyautoimmunity complexity, i.e., APECED-like conditions, also including patients affected by primary immunodeficiency. Our results evidenced a significant association of the S278R polymorphism of the AIRE gene with APECED-like conditions, including both patients affected by autoimmunity and immunodeficiency and patients with polyautoimmunity compared to healthy controls. A trend of association was also observed with the IVS9+6 G>A polymorphism. The results of this genetic analysis emphasize the need to look for additional genetic determinants playing in concert with AIRE polymorphisms. This will help to improve the diagnostic workup and ensure a precision medicine approach to targeted therapies in APECED-like patients.

Autoimmune Hepatitis Induced after Treatment of Syphilitic Hepatitis

We present a unique case of biopsy-proven syphilitic hepatitis which presented as severe acute liver injury with significant elevation in aminotransferases and bilirubin, and improved with antibiotic therapy. However, the patient returned weeks after initial presentation with new-onset acute liver injury and had developed hypergammaglobulinemia, positive autoantibody titers, and repeat liver biopsy demonstrating interface hepatitis, supporting a diagnosis of autoimmune hepatitis. He had an otherwise unrevealing etiologic workup, and responded to glucocorticoid therapy. We believe that syphilitic hepatitis and its treatment subsequently triggered an immunogenic response, leading to autoimmune hepatitis. Autoimmune hepatitis is a chronic liver disease thought to manifest as a result of predisposing genetic factors in combination with environmental insults, especially hepatotropic pathogens. Syphilis is a sexually transmitted disease caused by Treponema pallidum that has been associated with autoimmunity and the development of autoantibodies. We propose that in the setting of syphilitic hepatitis, a molecular mimicry event resulting from structural similarities between T. pallidum and liver antigens, as well as impaired regulatory T-cell function, led to the breakdown of immune tolerance and the onset of autoimmune hepatitis. To support this hypothesis, further molecular analyses and case series are necessary to determine if syphilitic hepatitis and its treatment are risk factors for the onset of autoimmune hepatitis. Autoimmune hepatitis should be considered early as the cause of acute liver injury in susceptible patients with risk factors for the disease, as prompt recognition and appropriate treatment may prevent progression of liver injury and result in improved outcomes.

Fucosterol of Marine Macroalgae: Bioactivity, Safety and Toxicity on Organism

Fucosterol (24-ethylidene cholesterol) is a bioactive compound belonging to the sterol group that can be isolated from marine algae. Fucosterol of marine algae exhibits various biological activities including anti-osteoarthritic, anticancer, anti-inflammatory, anti-photoaging, immunomodulatory, hepatoprotective, anti-neurological, antioxidant, algicidal, anti-obesity, and antimicrobial. Numerous studies on fucosterol, mainly focusing on the quantification and characterization of the chemical structure, bioactivities, and health benefits of fucosterol, have been published. However, there is no comprehensive review on safety and toxicity levels of fucosterol of marine algae. This review aims to discuss the bioactivities, safety, and toxicity of fucosterol comprehensively, which is important for the application and development of fucosterol as a bioactive compound in nutraceutical and pharmaceutical industries. We used four online databases to search for literature on fucosterol published between 2002 and 2020. We identified, screened, selected, and analyzed the literature using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses method and identified 43 studies for review. Despite the potential applications of fucosterol, we identified the need to fill certain related research gaps. Fucosterol exhibited low toxicity in animal cell lines, human cell lines, and animals. However, studies on the safety and toxicity of fucosterol at the clinical stage, which are required before fucosterol is developed for the industry, are lacking.

Recurrent Autoimmune Hepatitis and De Novo Autoimmune Hepatitis in the Liver Allograft

OBJECTIVES

Autoimmune hepatitis (AIH) is a form of severe hepatitis that can recur after orthotopic liver transplant (OLT). Presentation of AIH in patients with OLT who do not have a history of AIH is called de novo AIH (DNAIH). We evaluated the clinicopathologic characteristics of AIH and DNAIH.

METHODS

Clinicopathologic and outcome measures of 11 patients with recurrent AIH (RAIH) and 22 with DNAIH identified between 2000 and 2017 were compared.

RESULTS

Both cohorts showed female predominance. The mean clinical follow-up was 13 and 7.8 years in the in the RAIH and DNAIH groups, respectively (P = .1). Moderate portal inflammation was more common in patients with RAIH (64% vs 27%, P = .043). A trend was observed for more cases of DNAIH showing severe inflammation (36% vs 9%, P = .09) and submassive necrosis compared with RAIH (23% vs 0%, P = .086). A trend for more advanced fibrosis was also noted in the RAIH group (27% vs 5%, P = .059). Three patients with RAIH lost their grafts because of RAIH. Five-year disease-specific graft survival (GS) (P = .012) and overall GS (P = .015) were worse in patients with RAIH. Complement component 4d immunohistochemistry was positive in 2 patients with RAIH and 3 with DNAIH but showed no correlation with GS or other parameters.

CONCLUSIONS

RAIH seems to have a more aggressive clinical course than DNAIH and warrants closer clinical follow-up and aggressive treatment.

Association of Interleukin-6 and Interleukin-1 Family Gene Polymorphisms in Autoimmune Hepatitis

INTRODUCTION AND AIM

Autoimmune hepatitis (AIH) is an immune-mediated destruction of liver cells, in recognition of interface hepatitis, seropositivity for autoantibodies, and interface hepatitis in histology sections. Hepatocyte destruction in AIH is the direct result of CD4+ T-cell destruction. Yet, Th17 mediated immune attach and a diversity of cytokine networks, including pro-inflammatory cytokines such as Interleukin 1 (IL-1) and Interleukin 6 (IL-6), set the stage for the destructive liver damage.

MATERIAL AND METHOD

Peripheral blood samples from 57 patients, with AIH, recruited from referrals to the main pediatric hospital in Tehran. Single nucleotide polymorphisms for the following cytokines genes, were evaluated through, polymerase chain reaction with sequencespecific primers (PCR-SSP) assay: IL-1a (C/T -889), IL-1α (C/T -511), IL-1β (C/T +3962), IL-1 receptor (IL-1R; C/T Pst-I 1970), IL-1RA (C/T Mspa-I 11100), and IL-6 (C/G -174 and A/G nt565).

RESULTS

Significant higher frequency of genotype AA was detected in patients in IL-6 at position nt565 (15.8% in AIH patients vs. 2.9% in controls, p = 0.003). The haplotype GA of IL-6 at -174 and nt565, was significantly overrepresented in the AIH group, compared to (20.9% of AIH vs. 1.4% in controls p < 0.0001).

CONCLUSION

Results of our study, indicate significant deviation toward high yield IL-6 polymorphisms, in AIH patients. These data could bring new insights in pathophysiology of disease, which could contribute to developing novel treatments for AIH.

Primary Biliary Cholangitis and Autoimmune Hepatitis

Primary biliary cholangitis and autoimmune hepatitis are common autoimmune diseases of the liver. Both have typical clinical presentations, including certain autoantibodies on serologic testing. Histologic features are also often typical: primary biliary cholangitis shows bile duct destruction (sometimes with granulomas), and autoimmune hepatitis shows prominent portal and lobular lymphoplasmacytic inflammation. Both have a wide differential diagnosis, including one another; they may also simultaneously occur within the same patient. Careful use of clinical and histologic criteria may be necessary for diagnosis. First-line therapy is immunosuppression for autoimmune hepatitis and ursodeoxycholic acid for primary biliary cholangitis. Both diseases may progress to cirrhosis.

Variety of lung involvement in autoimmune liver diseases

The primary autoimmune liver diseases conventionally include primary biliary cholangitis, primary sclerosing cholangitis and autoimmune hepatitis. Despite of primary autoimmune affection of different parts of the hepatobiliary system, in the recent decades, a lot of data has emerged indicating the presence of extrahepatic manifestations of these diseases, in particular, lung lesions, such as nodular and interstitial changes with possible progression and development of fibrosis and respiratory failure. In case of lungs disease, both pulmonary parenchyma and lung vessels, pleura, and intrathoracic lymph nodes can be involved. The most sensitive and specific procedure to assess the extent of the lung lesions and their evolution is high-resolution computed tomography. Due to the possibility of long-term asymptomatic course of the pulmonary disease with development of irreversible changes in patients with autoimmune liver diseases, it seems reasonable to conduct screening studies aimed at early detection and treatment of lung lesions in this population.

Analysis of Differentially Expressed Proteins Involved in Autoimmune Cirrhosis and Normal Serum by iTRAQ Proteomics

PURPOSE

In order to study the candidate biomarkers in autoimmune cirrhosis (AIC).

EXPERIMENTAL DESIGN

Isobaric tags are first implemented for relative and absolute quantitation technology on proteins prepared from serum obtained from AIC and normal controls. Proteins found to be differentially expressed are identified with liquid chromatography electrospray ionization tandem mass spectrometry by using a Q Exactive classic ion trap mass spectrometer.

RESULTS

108 proteins (32 upregulated and 76 downregulated proteins) are identified from AIC samples, compared with the normal controls. Gene Ontology enrichment analysis, KEGG pathway analysis, and protein-protein interaction map by STRING show that they associate with multiple functional groups, including ion binding activity, peptidase activity, and enzyme regulator activity. Finally, the von Willebrand factor, insulin-like growth factor-binding protein complex acid labile subunit, transthyretin, adiponectin proteins are identified with western blot as candidate biomarkers for AIC.

CONCLUSIONS AND CLINICAL RELEVANCE

These findings offer a comprehensive profile of the AIC proteome about candidate biomarkers and provide a useful basis for further analysis of the pathogenic mechanism of AIC.

Pro: Steroids Can Be Withdrawn After Transplant in Recipients With Autoimmune Hepatitis

Corticosteroids have been a mainstay of immunosuppression following liver transplantation. However, evolution in the field of transplant immunology has produced steroid-free options, resulting in most transplant centers weaning steroids after transplant within days to months-an evidence-based management decision. Patients with autoimmune hepatitis (AIH), however, receive corticosteroids prior to transplant. This raises the question of whether these patients should also be weaned from corticosteroids. In this review, we discuss the benefits of avoiding steroid use in this population of patients-an approach that not only avoids the adverse effects of corticosteroids but does so without risking graft failure from recurrent AIH or from acute cellular rejection.

Fucosterol Protects against Concanavalin A-Induced Acute Liver Injury: Focus on P38 MAPK/NF-κB Pathway Activity

Objective

Fucosterol is derived from the brown alga Eisenia bicyclis and has various biological activities, including antioxidant, anticancer, and antidiabetic properties. The aim of this study was to investigate the protective effects of fucosterol pretreatment on Concanavalin A- (ConA-) induced acute liver injury in mice, and to understand its molecular mechanisms.

Materials and Methods

Acute liver injury was induced in BALB/c mice by ConA (25 mg/kg), and fucosterol (dissolved in 2% DMSO) was orally administered daily at doses of 25, 50, and 100 mg/kg. The levels of hepatic necrosis, apoptosis, and autophagy associated with inflammatory cytokines were measured at 2, 8, and 24 h.

Results

Fucosterol attenuated serum liver enzyme levels and hepatic necrosis and apoptosis induced by TNF-α, IL-6, and IL-1β. Fucosterol also inhibited apoptosis and autophagy by upregulating Bcl-2, which decreased levels of functional Bax and Beclin-1. Furthermore, reduced P38 MAPK and NF-κB signaling were accompanied by PPARγ activation.

Conclusion

This study showed that fucosterol could alleviate acute liver injury induced by ConA by inhibiting P38 MAPK/PPARγ/NF-κB signaling. These findings highlight that fucosterol is a promising potential therapeutic agent for acute liver injury.

Analytical "bake-off" of whole genome sequencing quality for the Genome Russia project using a small cohort for autoimmune hepatitis

A comparative analysis of whole genome sequencing (WGS) and genotype calling was initiated for ten human genome samples sequenced by St. Petersburg State University Peterhof Sequencing Center and by three commercial sequencing centers outside of Russia. The sequence quality, efficiency of DNA variant and genotype calling were compared with each other and with DNA microarrays for each of ten study subjects. We assessed calling of SNPs, indels, copy number variation, and the speed of WGS throughput promised. Twenty separate QC analyses showed high similarities among the sequence quality and called genotypes. The ten genomes tested by the centers included eight American patients afflicted with autoimmune hepatitis (AIH), plus one case’s unaffected parents, in a prelude to discovering genetic influences in this rare disease of unknown etiology. The detailed internal replication and parallel analyses allowed the observation of two of eight AIH cases carrying a rare allele genotype for a previously described AIH-associated gene (FTCD), plus multiple occurrences of known HLA-DRB1 alleles associated with AIH (HLA-DRB1-03:01:01, 13:01:01 and 7:01:01). We also list putative SNVs in other genes as suggestive in AIH influence.

Autoimmune liver disease and the enteric microbiome

The human enteric microbiome is highly complex and has more than 150 times more genes within it than its host. The host and the microbiome have a commensurate relationship that can evolve over time. The typically symbiotic relationship between the two can become pathogenic. The microbiome composition in adults reflects their history of exposure to bacteria and environmental factors during early life, their genetic background, age, interactions with the immune system, geographical location, and, most especially, their diet. Similarly, these factors are thought to contribute to the development of autoimmune disease. It is possible that alterations in the intestinal microbiome could lead to liver disease. There is emerging data for the contribution of the microbiome in development of primary sclerosing cholangitis, primary biliary cholangitis, and autoimmune hepatitis; liver disorders associated with aberrant immune function in genetically susceptible individuals.

Autoimmune hepatitis association with single nucleotide polymorphism of interleukin-2, but not interferon-gamma

BACKGROUND

Autoimmune hepatitis (AIH) is a chronic inflammation in hepatocellular tissues associated with circulating autoantibodies. Imbalance in T-cells population and dysregulation in several cytokine profiles has been implicated in pathogenesis of AIH. This study was performed to assess potential association of AIH with interleukin-2 (IL-2) and interferon-gamma (IFN-γ) genes single nucleotide polymorphisms (SNPs).

METHODS

Fifty-six patients with AIH and 139 healthy individuals were enrolled in this study. IL-2 and IFN-γ typing was performed, using polymerase chain reaction with sequence-specific primers (PCR-SSP) assay. The frequencies of alleles, genotypes and haplotypes in AIH patients were compared to healthy controls.

RESULTS

IL-2 T allele at position +166 (rs2069763) showed significant higher frequency in AIH group (36%), compared to the controls (21%) (OR=2.06; 95% CI, 1.24-3.43, P-value<0.01). The frequency of IL-2 TT genotype at +166 position was also associated with AIH (OR=18.68, 95% CI 3.74-126.04, P-value<0.01). G/T alleles of IL-2 at -330 (rs2069762) and A/T alleles on UTR +5644 position at IFN-γ and their subsequent haplotypes, did not show significant association with AIH.

CONCLUSIONS

This study identified IL-2T allele at +166 position and TT genotype as susceptibility gene in AIH which would provide better understandings into the mechanisms of AIH and potential immune modulation therapies.

Diagnosis and Management of Pediatric Autoimmune Liver Disease: ESPGHAN Hepatology Committee Position Statement

Paediatric autoimmune liver disease is characterized by inflammatory liver histology, circulating autoantibodies, and increased levels of IgG, in the absence of a known etiology. Three conditions have a likely autoimmune pathogenesis: autoimmune hepatitis (AIH), autoimmune sclerosing cholangitis, and de novo AIH after liver transplantation. Two types of pediatric AIH are recognized according to seropositivity for smooth muscle and/or antinuclear antibody (AIH-1) or liver kidney microsomal type 1 and/or anti-liver cytosol type 1 antibodies (AIH-2).Pertinent issues addressing the diagnosis, treatment, and long-term follow-up were formulated by a core group of ESPGHAN members. They have commissioned the first authors with execution of this project. Initially, they have performed a systematic literature search on MEDLINE, ResearchGate, and Mendeley databases during the last 30 years and produced a document focusing on prospective and retrospective studies in children. The ESPGHAN core group and ESPGHAN Hepatology Committee members voted on each recommendation, using a formal voting technique.

Glassy droplet inclusions within the cytoplasm of Kupffer cells: A novel ultrastructural feature for the diagnosis of pediatric autoimmune hepatitis

Since Kupffer cells/macrophages (KCs/MPs) may be involved in the pathogenesis of autoimmune hepatitis (AIH), this pioneer study was undertaken to evaluate KCs/MPs in pediatric AIH in transmission-electron microscope.

METHODS

Ultrastructural analyses were performed using liver biopsies from 14 children with clinicopathologically diagnosed AIH.

RESULTS

In all AIH children, ultrastructural findings revealed changes in the cells lining sinusoidal vessels, especially KCs/MPs and endothelial cells. KCs/MPs showed increased phagocytic activity and damaged mitochondria, frequently with accompanying intense fibrosis. In 10/14 AIH patients, the cytoplasm of sinusoidal KCs/MPs contained characteristic glassy droplet inclusions. They were round, sharply circumscribed, and contained homogeneous material and distinct translucent fields. Their ultrastructure was identical with the Russel bodies of plasma cells, which were also found in liver biopsies in the same patients.

CONCLUSION

Ultrastructural identification of characteristic cytoplasmic droplets with glassy appearance in KCs/MPs, never before described in AIH, provides a useful novel morphological feature in the diagnosis of this disease.

Imaging of autoimmune hepatitis and overlap syndromes

Autoimmune hepatitis (AIH) is an uncommon, chronic inflammatory, and relapsing liver disease of unknown origin that may lead to liver cirrhosis, hepatocellular carcinoma, liver transplantation, or death. AIH occurs in all age groups and races but can frequently manifest as acute fulminant hepatitis. Clinical presentation of AIH can have features similar to primary sclerosing cholangitis (PSC) and primary biliary cirrhosis (PBC), and these diseases may coexist leading to overlap syndromes. Although histological diagnosis is necessary, imaging features often can demonstrate characteristics that may be helpful to distinguish these diseases. Imaging features of AIH are those of chronic liver disease, and imaging plays important role in detection of complications and ruling out other possible causes of chronic liver disease. Emerging techniques such as elastography provide non-invasive options for diagnosis of significant fibrosis and cirrhosis during clinical follow-up as well as assessment of response to treatment. In this study, we will describe imaging findings in AIH and overlap syndromes.

Absence of keratin 8 or 18 promotes antimitochondrial autoantibody formation in aging male mice

Human mutations in keratin 8 (K8) and keratin 18 (K18), the intermediate filament proteins of hepatocytes, predispose to several liver diseases. K8-null mice develop chronic liver injury and fragile hepatocytes, dysfunctional mitochondria, and Th2-type colitis. We tested the hypothesis that autoantibody formation accompanies the liver damage that associates with K8/K18 absence. Sera from wild-type control, K8-null, and K18-null mice were analyzed by immunoblotting and immunofluorescence staining of cell and mouse tissue homogenates. Autoantibodies to several antigens were identified in 81% of K8-null male mice 8 mo or older. Similar autoantibodies were detected in aging K18-null male mice that had a related liver phenotype but normal colon compared with K8-null mice, suggesting that the autoantibodies are linked to liver rather than colonic disease. However, these autoantibodies were not observed in nontransgenic mice subjected to 4 chronic injury models. The autoantigens are ubiquitous and partition with mitochondria. Mass spectrometry and purified protein analysis identified, mitochondrial HMG-CoA synthase, aldehyde dehydrogenase, and catalase as the primary autoantigens, and glutamate dehydrogenase and epoxide hydrolase-2 as additional autoantigens. Therefore, absence of the hepatocyte keratins results in production of anti-mitochondrial autoantibodies (AMA) that recognize proteins involved in energy metabolism and oxidative stress, raising the possibility that AMA may be found in patients with keratin mutations that associate with liver and other diseases.

Vitamin C exerts beneficial hepatoprotection against Concanavalin A-induced immunological hepatic injury in mice through inhibition of NF-κB signal pathway

The present study was designed to investigate the potential benefits of vitamin C (VC) in treating immunological liver injury induced by Concanavalin A (Con A, 20 mg kg(-1)) in mice. Interestingly, VC administration significantly reduced serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and total-bilirubin (T-bilirubin) in Con A-lesioned mice, while serum concentrations of albumin and total-protein (T-protein) were increased. Moreover, inflammatory cytokine profiles, such as interferon-gamma (IFN-γ), interleukin-4 (IL-4), interleukin-6 (IL-6) and interleukin-8 (IL-8), were decreased in liver tissue by VC administration. Morphological examination showed that Con A-induced liver damage was effectively mitigated. As shown in RT-PCR assay, VC administration resulted in down-regulated mRNA expressions of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). In addition, VC contributed towards the reduction of intrahepatic tumor necrosis factor alpha (TNF-α) and the receptor (TNF-R) protein levels, as well as decreasing IKKβ, p-IκBα, p50 and NF-κB expressions; furthermore, VC blocked intranuclear DNA-binding NF-κB locus. Our findings show that VC effectively attenuates Con A-mediated immunotoxicity in liver tissue, through an underlying mechanism which relates to dampening of the intrahepatic NF-κB signal pathway, thereby reducing cytotoxicity within hepatocytes.

The possible implication of the S250C variant of the autoimmune regulator protein in a patient with autoimmunity and immunodeficiency: in silico analysis suggests a molecular pathogenic mechanism for the variant

Autoimmunity can develop from an often undetermined interplay of genetic and environmental factors. Rare forms of autoimmune conditions may also result from single gene mutations as for autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy, an autosomal recessive disease associated with mutated forms of the autoimmune regulator gene. It was proposed that genetic variability in the autoimmune regulator locus, in particular heterozygous loss-of-function mutations, might favor the development of organ-specific autoimmunity by affecting the presentation of self-antigens in the thymus. Indeed, heterozygous mutations of the autoimmune regulator gene were reported in patients with organ-specific autoimmunity. Also, in primary immunodeficiencies, a breakdown in central/peripheral tolerance frequently produces association with autoimmunity. The causative link may involve a common genetic background and several gene defects have been identified as putative culprits. We report a unique patient, a 14 year old male from Lazio region, affected by common variable immunodeficiency associated with autoimmune manifestations (alopecia, onychodystrophy) and heterozygote for the S250C variant located in the SAND domain of the autoimmune regulator gene protein. To our knowledge this is the first report of the S250C variant in a patient bearing this unusual combination of autoimmunity and immunodeficiency. To obtain insights into the possible molecular effects of the S250C variant, we have carried out an in silico analysis of the SAND domain structure of the autoimmune regulator protein. In particular, homology modeling has allowed us to observe that the cysteine introduced by the S250C variant is surrounded by cationic residues, and by means of molecular dynamics simulations together with pKa calculations, we have shown that these residues remain stably proximal to cysteine-250 lowering its pKa and thus conferring high chemical reactivity to the mutated residue. We propose that the enhanced reactivity of cysteine-250, which is likely to impair the protein function but probably insufficient to produce alone a phenotype as a heterozygous S250C variant due to compensation mechanisms, might become manifest when combined with other genetic/environmental factors. These results can provide the rationale for the patient's unusual phenotype, shedding new light into the pathogenesis of the clinical association of autoimmunity and immunodeficiency.

Noninvasive markers in the assessment and management of autoimmune liver diseases

Historically, liver biopsy has been used to determine the etiology of liver disease, the degree of inflammation, the stage of liver fibrosis, and the response to treatments. In the last decade, the advent of noninvasive tests has improved the diagnosis and management of autoimmune liver diseases. For example, serum markers can identify hepatic inflammation, whereas ultrasound and MRI can diagnose liver fibrosis. Physicians now have a much larger repertoire of diagnostic tests to assess the liver parenchyma compared with liver biopsy alone. In some rare cases, noninvasive tests may provide an alternative to liver biopsy. In general, however, these noninvasive tests complement liver biopsy and provide quick, accurate, and reliable adjunctive data.

Occult hepatitis C virus infection in patients with autoimmune hepatitis

BACKGROUND

Occult hepatitis C virus infection (OCI) is recognized by finding hepatitis C virus (HCV) RNA in hepatocytes without detectable anti-HCV antibodies and viral RNA in plasma. Autoimmune hepatitis (AIH) is a chronic and generally progressive disease without exactly-identified etiology.

OBJECTIVES

This study aimed to determine the prevalence of OCI among patients with AIH and to evaluate the tests used to rule out HCV infection in diagnosing AIH.

PATIENTS AND METHODS

Between July 2012 to February 2013, 35 Iranian patients with AIH who attended Tehran Hepatitis Center were investigated. For identifying OCI, detection of HCV RNA in both ultracentrifuged serum samples and peripheral blood mononuclear cells (PBMCs) was used. Data analysis was performed using SPSS.

RESULTS

Six males and 29 females with mean disease duration of 77.1 ± 39.5 month and mean age of 43.62 ± 12.67 years were investigated. All cases were negative for anti-HCV antibody and we could not find any HCV RNA in ultracentrifuged serum samples and PBMCs.

CONCLUSIONS

With our laboratory diagnostic method, it seems that there are no cases of OCI in patients with AIH. However, we recommend further studies with more samples and more precise laboratory method.

Presence of antibodies against self human leukocyte antigen class II molecules in autoimmune hepatitis

Autoimmune hepatitis (AIH) can arise de novo after liver transplantation (LT) for non-autoimmune liver diseases. Considering the identical features of de novo AIH after LT and classical AIH, as well as the importance of anti-human leukocyte antigen (HLA) antibodies in graft rejection, we investigated the presence of circulating anti-HLA class II antibodies in the sera of 35 patients with AIH, 30 patients with primary biliary cirrhosis (PBC), and 30 healthy donors using fluorescent dye-impregnated beads bound to HLA molecules. We then investigated the allele specificity of the antibodies and identified the HLA alleles in each patient using DNA-based HLA typing. We also examined HLA class II expression in liver samples using immunohistochemistry. Anti-HLA class II antibodies were detected significantly more frequently in the patients with AIH (88.1%) than in the patients with PBC (33.3%) or in the healthy donors (13.3%) (both P <0.01). We confirmed that the anti-HLA class II antibodies in the AIH patients showed specificity for several HLA class II alleles, including self HLA class II alleles. Moreover, positive reactivity with anti-self HLA class II antibodies was associated with higher serum transaminase levels. In conclusion, we demonstrated, for the first time, that antibodies against self HLA class II alleles were detectable in patients with AIH. Our results suggest that an antibody-mediated immune response against HLA class II molecules on hepatocytes may be involved in the pathogenesis or acceleration of liver injury in AIH.

Current progress in research of overlap syndrome of autoimmune liver diseases

Autoimmune liver diseases (AILDs) include autoimmune hepatitis (AIH), primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). Overlap syndrome (OS) of AILDs is a relatively infrequent disease that has the combined clinical, biochemical, serological, histological and radiological features of AIH and PBC or PSC, mainly comprising AIH-PBC and AIH-PSC overlap syndromes. The AIH-PBC overlap syndrome is common in adults, while the AIH-PSC overlap syndrome is predominantly found in children. Overlap syndromes have a progressive course and may finally lead to liver cirrhosis and liver failure without treatment. High-dose ursodeoxycholic acid (UDCA) combined with immunosuppressive therapy with corticosteroids and/or azathioprine (AZA) is usually used in both AIH-PBC and AIH-PSC overlap syndromes. At present, liver transplantation is the only option with known therapeutic benefit for end-stage patients.

Analysis of the autoimmune regulator gene in patients with autoimmune non-APECED polyendocrinopathies

The pathogenesis of autoimmunity was derived from a complex interaction of genetic and environmental factors. Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy is a rare autosomal recessive disease caused by mutations in the autoimmune regulator (AIRE) gene. AIRE gene variants and, in particular, heterozygous loss-of-function mutations were also discovered in organ-specific autoimmune disorders, possibly contributing to their etiopathogenesis. It was suggested that even predisposition to develop certain autoimmune conditions may be derived from AIRE gene polymorphisms including S278R and intronic IVS9+6 G>A. In this study we unravel the hypothesis on whether AIRE gene variants may predispose individuals to associated autoimmune conditions in 41 Italian patients affected by non-APECED autoimmune polyendocrinopathies. We could not detect any heterozygous mutations of the AIRE gene. Although a trend of association was observed, heterozygous polymorphisms S278R and IVS9+6 G>A were detected in patients without statistically significant prevalence than in controls. Their putative contribution to autoimmune polyendocrinopathies and their predictive value in clinical strategies of disease development could be unravelled by analysing a larger sample of diseased patients and healthy individuals.

The role of natural killer cells in autoimmune liver disease: a comprehensive review

Natural Killer (NK) cells are important players of the innate arm of the immune system and provide an early defense against pathogens and tumor-transformed cells. Peripheral blood NK (PB-NK) cells were first identified because of their ability to spontaneously kill tumor-cell targets in vitro without the need for specific antigen priming, which is the reason that they were named 'natural killer' cells. The characterization of NK cells in human tissues and body organs represented another important step forward to better understand their physiology and physiopathology. In this regard, many reports revealed over the past decade a differential anatomic distribution of NK cell subsets in several sites such as the intestine, lung, cervix, placenta and liver as well as in secondary lymphoid organs such as spleen, lymph nodes and tonsils. Among all these tissues, the liver is certainly unique as its parenchyma contains an unusually high number of infiltrating immune cells with 30-50% of total lymphocytes being NK cells. Given the constant liver intake of non-self antigens from the gastrointestinal tract via the portal vein, hepatic NK (H-NK) cells must retain a certain degree of tolerance in the context of their immune-surveillance against dangers to the host. Indeed, the breakdown of the tolerogenic state of the liver-associated immune system has been shown to induce autoimmunity. However, the role of NK cells during the course of autoimmune liver diseases is still being debated mainly because a complete characterization of H-NK cells normally resident in healthy human liver has not yet been fully disclosed. Furthermore, the differences in phenotype and functions between human and mouse H-NK cells often preclude translation of results obtained from murine models into experimental approaches to be performed in humans. Here, we provide an extensive characterization of the phenotype of H-NK cells physiologically resident in the human liver by both mentioning data available in literature and including a set of original results recently developed in our laboratory. We then review our current knowledge in regard to the contribution of H-NK cells in regulating local immune homeostasis and tolerance as well as in inducing the development of liver autoimmunity.

Autoimmune Hepatitis

Autoimmune hepatitis is a chronic necroinflammatory disease of unknown etiology that is characterized by increased aminotransferases, serum autoantibodies, increased immunoglobulin G levels, and histological interface hepatitis. The disease does not have a pathognomonic clinical, laboratory, or histological feature; diagnosis depends on a combination of clinical and pathologic criteria which also form the basis for a weighted scoring system to aid diagnosis. Liver biopsy is an essential part of the diagnostic criteria and is also crucial to the management of the disease. This review focuses on the diagnosis, microscopic features, differential diagnosis and overlap syndromes of autoimmune hepatitis.

Nuclear receptors as drug targets in cholestatic liver diseases

Cholestatic liver diseases encompass a wide spectrum of disorders with different causes, resulting in impaired bile flow and accumulation of bile acids and other potentially hepatotoxic cholephils. The understanding of the molecular mechanisms of bile formation and cholestasis has recently improved significantly through new insights into nuclear receptor (patho)biology. Nuclear receptors are ligand-activated transcription factors, which act as central players in the regulation of genes responsible for elimination and detoxification of biliary constituents accumulating in cholestasis. They also control other pathophysiologic processes such as inflammation, fibrogenesis, and carcinogenesis involved in the pathogenesis and disease progression of cholestasis liver diseases.

Cutting edge: chronic inflammatory liver disease in mice expressing a CD28-specific ligand

Inflammation of the normally tolerant liver microenvironment precedes the development of chronic liver disease. Study of the pathogenesis of autoimmune liver diseases, such as autoimmune hepatitis (AIH), has been hampered by a lack of autochthonous chronic animal models. Through our studies of T cell costimulation, we generated transgenic mice expressing a ligand specific for the CD28 receptor, which normally shares ligands with the related inhibitory receptor CTLA-4. The mice spontaneously develop chronic inflammatory liver disease with several pathologies found in AIH, including elevated serum aminotransferases in the context of normal alkaline phosphatase and bilirubin levels, lymphocytic inflammation, focal necrosis, oval cell hyperplasia, and fibrosis. The prevalence of IFN-γ-producing CD8(+) T cells in the livers of transgenic mice suggests a role for autoimmune cytotoxicity in the chronic disease state. The CD28 ligand-specific transgenic mice will facilitate evaluation of CD8(+) T cell function in liver disease pathologies found in AIH.