Autoimmune hepatitis: A comprehensive review

COVID-19-related liver injury: Mechanisms, diagnosis, management; its impact on pre-existing conditions, cancer and liver transplant: A comprehensive review

AIMS

This review explores the mechanisms, diagnostic approaches, and management strategies for COVID-19-induced liver injury, with a focus on its impact on patients with pre-existing liver conditions, liver cancer, and those undergoing liver transplantation.

MATERIALS AND METHODS

A comprehensive literature review included studies on clinical manifestations of liver injury due to COVID-19. Key areas examined were direct viral effects, drug-induced liver injury, cytokine storms, and impacts on individuals with chronic liver diseases, liver transplants, and the role of vaccination. Data were collected from clinical trials, observational studies, case reports, and review literature.

KEY FINDINGS

COVID-19 can cause a spectrum of liver injuries, from mild enzyme elevations to severe hepatic dysfunction. Injury mechanisms include direct viral invasion, immune response alterations, drug toxicity, and hypoxia-reperfusion injury. Patients with chronic liver conditions (such as alcohol-related liver disease, nonalcoholic fatty liver disease, cirrhosis, and hepatocellular carcinoma) face increased risks of severe outcomes. The pandemic has worsened pre-existing liver conditions, disrupted cancer treatments, and complicated liver transplantation. Vaccination remains crucial for reducing severe disease, particularly in chronic liver patients and transplant recipients. Telemedicine has been beneficial in managing patients and reducing cross-infection risks.

SIGNIFICANCE

This review discusses the importance of improved diagnostic methods and management strategies for liver injury caused by COVID-19. It emphasizes the need for close monitoring and customized treatment for high-risk groups, advocating for future research to explore long-term effects, novel therapies, and evidence-based approaches to improve liver health during and after the pandemic.

Role of microbiome in autoimmune liver diseases

The microbiome plays a crucial role in integrating environmental influences into host physiology, potentially linking it to autoimmune liver diseases, such as autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. All autoimmune liver diseases are associated with reduced diversity of the gut microbiome and altered abundance of certain bacteria. However, the relationship between the microbiome and liver diseases is bidirectional and varies over the course of the disease. This makes it challenging to dissect whether such changes in the microbiome are initiating or driving factors in autoimmune liver diseases, secondary consequences of disease and/or pharmacological intervention, or alterations that modify the clinical course that patients experience. Potential mechanisms include the presence of pathobionts, disease-modifying microbial metabolites, and more nonspecific reduced gut barrier function, and it is highly likely that the effect of these change during the progression of the disease. Recurrent disease after liver transplantation is a major clinical challenge and a common denominator in these conditions, which could also represent a window to disease mechanisms of the gut-liver axis. Herein, we propose future research priorities, which should involve clinical trials, extensive molecular phenotyping at high resolution, and experimental studies in model systems. Overall, autoimmune liver diseases are characterized by an altered microbiome, and interventions targeting these changes hold promise for improving clinical care based on the emerging field of microbiota medicine.

Hepatic immune regulation and sex disparities

Chronic liver disease is a major cause of morbidity and mortality worldwide. Epidemiology, clinical phenotype and response to therapies for gastrointestinal and liver diseases are commonly different between women and men due to sex-specific hormonal, genetic and immune-related factors. The hepatic immune system has unique regulatory functions that promote the induction of intrahepatic tolerance, which is key for maintaining liver health and homeostasis. In liver diseases, hepatic immune alterations are increasingly recognized as a main cofactor responsible for the development and progression of chronic liver injury and fibrosis. In this Review, we discuss the basic mechanisms of sex disparity in hepatic immune regulation and how these mechanisms influence and modify the development of autoimmune liver diseases, genetic liver diseases, portal hypertension and inflammation in chronic liver disease. Alterations in gut microbiota and their crosstalk with the hepatic immune system might affect the progression of liver disease in a sex-specific manner, creating potential opportunities for novel diagnostic and therapeutic approaches to be evaluated in clinical trials. Finally, we identify and propose areas for future basic, translational and clinical research that will advance our understanding of sex disparities in hepatic immunity and liver disease.

Concanavalin-A-Induced Acute Liver Injury in Mice

Acute liver injury is a life-threatening disease. Although immune responses are involved in the development and exacerbation of acute liver injury, the cellular and molecular mechanisms are not fully understood. Intravenous administration of the plant lectin concanavalin A (ConA) is widely used as a model of acute liver injury. ConA triggers T cell activation and cytokine production by crosslinking glycoproteins, including the T cell receptor, leading to the infiltration of myeloid cells into the liver and the subsequent amplification of inflammation in the liver. Thus, the pathogenesis of ConA-induced acute liver injury is considered a model of immune-mediated acute liver injury or autoimmune hepatitis in humans. However, the severity of the liver injury and the analyses of immune cells and non-hematopoietic cells in the liver following ConA injection are significantly influenced by the experimental conditions. This article outlines protocols for ConA-induced acute liver injury in mice and evaluation methods for liver injury, immune cells, and non-hematopoietic cells in the liver. © 2024 Wiley Periodicals LLC. Basic Protocol 1: Induction of acute liver injury by ConA injection Basic Protocol 2: Evaluation of inflammatory cytokines in mouse plasma Basic Protocol 3: Preparation of liver sections and histological analysis of liver injury Basic Protocol 4: Preparation of liver immune cells Basic Protocol 5: Preparation of hepatocytes, endothelial cells, and hepatic stellate cells Basic Protocol 6: Flow cytometry of immune and non-hematopoietic liver cells Basic Protocol 7: Flow cytometric sorting of endothelial cells and hepatic stellate cells Basic Protocol 8: Quantitative reverse transcription polymerase chain reaction.

Targeting chronic liver diseases: Molecular markers, drug delivery strategies and future perspectives

Chronic liver inflammation, a pervasive global health issue, results in millions of annual deaths due to its progression from fibrosis to the more severe forms of cirrhosis and hepatocellular carcinoma (HCC). This insidious condition stems from diverse factors such as obesity, genetic conditions, alcohol abuse, viral infections, autoimmune diseases, and toxic accumulation, manifesting as chronic liver diseases (CLDs) such as metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic dysfunction-associated steatohepatitis (MASH), alcoholic liver disease (ALD), viral hepatitis, drug-induced liver injury, and autoimmune hepatitis. Late detection of CLDs necessitates effective treatments to inhibit and potentially reverse disease progression. However, current therapies exhibit limitations in consistency and safety. A potential breakthrough lies in nanoparticle-based drug delivery strategies, offering targeted delivery to specific liver cell types, such as hepatocytes, Kupffer cells, and hepatic stellate cells. This review explores molecular targets for CLD treatment, ongoing clinical trials, recent advances in nanoparticle-based drug delivery, and the future outlook of this research field. Early intervention is crucial for chronic liver disease. Having a comprehensive understanding of current treatments, molecular biomarkers and novel nanoparticle-based drug delivery strategies can have enormous impact in guiding future strategies for the prevention and treatment of CLDs.

NLRP3 Inflammasome in Acute and Chronic Liver Diseases

NLRP3 (NOD-, LRR-, and pyrin domain-containing protein 3) is an intracellular complex that upon external stimuli or contact with specific ligands, recruits other components, forming the NLRP3 inflammasome. The NLRP3 inflammasome mainly mediates pyroptosis, a highly inflammatory mode of regulated cell death, as well as IL-18 and IL-1β production. Acute and chronic liver diseases are characterized by a massive influx of pro-inflammatory stimuli enriched in reactive oxygen species (ROS) and damage-associated molecular patterns (DAMPs) that promote the assemblage and activation of the NLRP3 inflammasome. As the major cause of inflammatory cytokine storm, the NLRP3 inflammasome exacerbates liver diseases, even though it might exert protective effects in regards to hepatitis C and B virus infection (HCV and HBV). Here, we summarize the current knowledge concerning NLRP3 inflammasome function in both acute and chronic liver disease and in the post liver transplant setting, focusing on the molecular mechanisms involved in NLRP3 activity.

Are Gender Differences Important for Autoimmune Liver Diseases?

Gender Medicine has had an enormous expansion over the last ten years. Autoimmune liver diseases include several conditions, i.e., autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), and conditions involving the liver or biliary tree overlapping with AIH, as well as IgG4-related disease. However, little is known about the impact of sex in the pathogenesis and natural history of these conditions. The purpose of this review is to provide an update of the gender disparities among the autoimmune liver diseases by reviewing the data published from 1999 to 2023. The epidemiology of these diseases has been changing over the last years, due to the amelioration of knowledge in their diagnosis, pathogenesis, and treatment. The clinical data collected so far support the existence of sex differences in the natural history of autoimmune liver diseases. Notably, their history could be longer than that which is now known, with problems being initiated even at a pediatric age. Moreover, gender disparity has been observed during the onset of complications related to end-stage liver disease, including cancer incidence. However, there is still an important debate among researchers about the impact of sex and the pathogenesis of these conditions. With this review, we would like to emphasize the urgency of basic science and clinical research to increase our understanding of the sex differences in autoimmune liver diseases.

Liver biopsy for assessment of suspected drug-induced liver injury in metabolic dysfunction-associated steatohepatitis clinical trials: Expert consensus from the Liver Forum

BACKGROUND

Causality assessment of suspected drug-induced liver injury (DILI) during metabolic dysfunction-associated steatohepatitis (MASH) clinical trials can be challenging, and liver biopsies are not routinely performed as part of this evaluation. While the field is moving away from liver biopsy as a diagnostic and prognostic tool, information not identified by non-invasive testing may be provided on histology.

AIM

To address the appropriate utilisation of liver biopsy as part of DILI causality assessment in this setting.

METHODS

From 2020 to 2022, the Liver Forum convened a series of webinars on issues pertaining to liver biopsy during MASH trials. The Histology Working Group was formed to generate a series of consensus documents addressing these challenges. This manuscript focuses on liver biopsy as part of DILI causality assessment.

RESULTS

Expert opinion, guidance and recommendations on the role of liver biopsy as part of causality assessment of suspected DILI occurring during clinical trials for a drug(s) being developed for MASH are provided. Lessons learned from prior MASH programs are reviewed and gaps identified.

CONCLUSIONS

Although there are no pathognomonic features, histologic evaluation of suspected DILI during MASH clinical trials may alter patient management, define the pattern and severity of injury, detect findings that favour a diagnosis of DILI versus MASH progression, identify prognostic features, characterise the clinicopathological phenotype of DILI, and/or define lesions that influence decisions about trial discontinuation and further development of the drug.

PD-L1 expression levels in mesenchymal stromal cells predict their therapeutic values for autoimmune hepatitis

BACKGROUND

Autoimmune hepatitis is a chronic inflammatory hepatic disorder with no effective treatment. Mesenchymal stromal cells (MSCs) have emerged as a promising treatment owing to their unique advantages. However, their heterogeneity is hampering use in clinical applications.

METHODS

Wharton's jelly derived MSCs (WJ-MSCs) were isolated from 58 human donors using current good manufacturing practice conditions. Gene expression profiles of the WJ-MSCs were analyzed by transcriptome and single-cell RNA-sequencing (scRNA-seq), and subsequent functional differences were assessed. Expression levels of programmed death-ligand 1 (PD-L1) were used as an indicator to screen WJ-MSCs with varied immunomodulation activities and assessed their corresponding therapeutic effects in a mouse model of concanavalin A-induced autoimmune hepatitis.

RESULTS

The 58 different donor-derived WJ-MSCs were grouped into six gene expression profile clusters. The gene in different clusters displayed obvious variations in cell proliferation, differentiation bias, trophic factor secretion, and immunoregulation. Data of scRNA-seq revealed four distinct WJ-MSCs subpopulations. Notably, the different immunosuppression capacities of WJ-MSCs were positively correlated with PD-L1 expression. WJ-MSCs with high expression of PD-L1 were therapeutically superior to WJ-MSCs with low PD-L1 expression in treating autoimmune hepatitis.

CONCLUSION

PD-L1 expression levels of WJ-MSCs could be regarded as an indicator to choose optimal MSCs for treating autoimmune disease. These findings provided novel insights into the quality control of MSCs and will inform improvements in the therapeutic benefits of MSCs.

A novel web-based online nomogram to predict advanced liver fibrosis in patients with autoimmune hepatitis-primary biliary cholangitis overlap syndrome

Background

Patients with autoimmune hepatitis-primary biliary cholangitis (AIH-PBC) overlap syndrome have a worse prognosis compared to AIH or PBC alone and accurately predicting the severity and dynamically monitoring the progression of disease are therefore essential. We aimed to develop a nomogram-based model to predict advanced liver fibrosis in patients with AIH-PBC overlap syndrome.

Methods

A total of 121 patients with AIH-PBC overlap syndrome were retrospectively included and randomly assigned to a development set and a validation set. Backward stepwise regression's best model with the lowest AIC was employed to create a nomogram. Diagnose accuracy was evaluated using the area under the receiver operator characteristic curve (AUROC), calibration analysis, and decision curve analysis (DCA) and was compared with aspartate aminotransferase-to-platelet ratio (APRI) and fibrosis index based on four factors-4 (FIB-4) score.

Results

The median age of patients was 53.0 years (IQR: 46.0-63.0), and female patients accounted for 95.0 %. Platelets, globulin, total bilirubin, and prothrombin time were associated with advanced fibrosis (≥S3) and used to construct an AIH-PBC overlap syndrome fibrosis (APOSF)-nomogram (available online at https://ndth-zzy.shinyapps.io/APOSF-nomogram/). The AUROCs of APOSF-nomogram were 0.845 (95 % CI: 0.754-0.936) and 0.843 (95 % CI: 0.705-0.982) in development set and validation set respectively, which was significantly better than APRI and FIB-4. Calibration revealed that the estimated risk fits well with biopsy-proven observation. DCA outperformed APRI and FIB4 in terms of net benefit, demonstrating clinical utility.

Conclusion

This novel non-invasive web-based online APOSF-nomogram provided a convenient tool for identifying advanced fibrosis in patients with AIH-PBC overlap syndrome. Further prospective, multicenter studies with large sample size are necessary to validate the applicability of APOSF-nomogram.

sFgl2 gene-modified MSCs regulate the differentiation of CD4+ T cells in the treatment of autoimmune hepatitis

BACKGROUND

Autoimmune hepatitis (AIH) is a T-cell-mediated autoimmune liver disease that can lead to liver injury and has a poor long-term prognosis. Mesenchymal stromal cells (MSCs) have immunosuppressive effects and can treat AIH. CD4+ T cells express the unique inhibitory Fcγ receptor (FcγRIIB), which is the only receptor for the immunosuppressive factor soluble fibrinogen-like protein 2 (sFgl2). This study aimed to examine the therapeutic effect of sFgl2 gene-modified MSCs (sFgl2-MSCs) on AIH.

METHODS

MSCs were obtained from the inguinal fat of mice and cocultured with CD4+ T cells sorted from mouse spleens. FcγRIIB expression on CD4+ T cells was determined by flow cytometry. sFgl2 expression in MSCs transfected with lentiviral vectors carrying the Fgl2 gene and a green fluorescent protein-encoding sequence was determined by enzyme-linked immunosorbent assay. The percentages of Th1 cells Th17 cells and regulatory T cells (Tregs) were determined by flow cytometry And the levels of p-SHP2 and p-SMAD2/3 were detected by Western blotting after the cells were cocultured with MSCs for 72 h. After locating MSCs by in vivo imaging Con A-induced experimental AIH mice were randomly divided into 4 groups and administered different treatments. After 24 h histopathological scores liver function and cytokine levels were examined and the proportions of CD4+ T cells CD8+ T cells Tregs Th17 cells and Th1 cells in the spleen and liver were determined by flow cytometry. In addition immunohistochemical staining was used to detect the liver infiltration of T-bet-, Foxp3- and RORγ-positive cells.

RESULTS

FcγRIIB expression on CD4+ T cells was upregulated after coculture with MSCs. After coculture with sFgl2-MSCs, the proportion of Tregs among CD4+ T cells increased, the proportion of Th17 and Th1 cells decreased, and the levels of p-SHP2 and p-SMAD2/3 increased. In vivo, sFgl2-MSCs significantly improved liver function, decreased liver necrosis area, decreased tumor necrosis factor-α, interleukin (IL)-1β and IL-6 expression, increased IL-10 expression, reduced liver infiltration of CD4+ T and CD8+ T cells, increased the proportion of Tregs and reduced the proportions of Th17 and Th1 cells in mice.

CONCLUSION

By promoting Tregs differentiation and inhibiting Th17 and Th1 cell differentiation, sFgl2 gene-modified MSCs have a more powerful therapeutic effect on Con A-induced experimental AIH and may represent a strategy for the clinical treatment of AIH.

Celastrol pretreatment attenuates concanavalin A-induced hepatitis in mice by suppressing interleukin-6/STAT3-interleukin-17 signaling

BACKGROUND AND AIM

Celastrol is extracted from Tripterygium wilfordii Hook F. It has been reported to have protective effects against various liver diseases and immune regulation of autoimmune diseases. However, little is known about whether celastrol protects against immune-mediated hepatitis. This study aimed to investigate the effect of celastrol on liver injury induced by concanavalin A (ConA) and the potential mechanisms.

METHODS

Intravenous administration of ConA was applied to induce acute liver injury in mice with or without pretreatment of celastrol. The effects of celastrol on ConA-induced liver injury were further demonstrated by biochemical and histopathological assessments, immunoblotting, and flow cytometry analysis.

RESULTS

Both biochemical and histopathological observations showed that pretreatment of celastrol significantly ameliorated liver injury induced by ConA. Moreover, the hepatocyte apoptosis and inflammatory responses induced by ConA were also improved in celastrol-pretreated mice. Further studies revealed that these improvements were characterized as the celastrol-mediated suppression of total interleukin (IL)-17 from liver mononuclear cells in ConA-treated mice. Flow cytometry analysis suggested that celastrol specifically decreased IL-17 production by CD4⁺ T cells but not by CD8⁺ T cells. Fundamentally, pretreatment with celastrol inhibited both the IL-6 produced by F4/80⁺ macrophages and the IL-6 receptor on Th17 cells in the liver, which further led to the downregulated activation of STAT3, thus accounting for blocked Th17 signaling.

CONCLUSIONS

Celastrol may exhibit immune regulatory effects by regulating IL-6/STAT3-IL-17 signaling in ConA-induced hepatitis, which suggested new potentials for celastrol to be applied in treating immune-mediated liver diseases.

COVID-19 and liver injury: Pathophysiology, risk factors, outcome and management in special populations

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 is an ongoing health concern. In addition to affecting the respiratory system, COVID-19 can potentially damage other systems in the body, leading to extra-pulmonary manifestations. Hepatic manifestations are among the common consequences of COVID-19. Although the precise mechanism of liver injury is still questionable, several mechanisms have been hypothesized, including direct viral effect, cytokine storm, hypoxic-ischemic injury, hypoxia-reperfusion injury, ferroptosis, and hepatotoxic medications. Risk factors of COVID-19-induced liver injury include severe COVID-19 infection, male gender, advanced age, obesity, and underlying diseases. The presentations of liver involvement comprise abnormalities in liver enzymes and radiologic findings, which can be utilized to predict the prognosis. Increased gamma-glutamyltransferase, aspartate aminotransferase, and alanine aminotransferase levels with hypoalbuminemia can indicate severe liver injury and anticipate the need for intensive care units’ hospitalization. In imaging, a lower liver-to-spleen ratio and liver computed tomography attenuation may indicate a more severe illness. Furthermore, chronic liver disease patients are at a higher risk for severe disease and death from COVID-19. Nonalcoholic fatty liver disease had the highest risk of advanced COVID-19 disease and death, followed by metabolic-associated fatty liver disease and cirrhosis. In addition to COVID-19-induced liver injury, the pandemic has also altered the epidemiology and pattern of some hepatic diseases, such as alcoholic liver disease and hepatitis B. Therefore, it warrants special vigilance and awareness by healthcare professionals to screen and treat COVID-19-associated liver injury accordingly.

Hepatocyte estrogen sulfotransferase inhibition protects female mice from concanavalin A-induced T cell-mediated hepatitis independent of estrogens

Autoimmune hepatitis (AIH) is a typical T cell-mediated chronic liver disease with a higher incidence in females. However, the molecular mechanism for the female predisposition is poorly understood. Estrogen sulfotransferase (Est) is a conjugating enzyme best known for its function in sulfonating and deactivating estrogens. The goal of this study is to investigate whether and how Est plays a role in the higher incidence of AIH in females. Concanavalin A (ConA) was used to induce T cell-mediated hepatitis in female mice. We first showed that Est was highly induced in the liver of ConA-treated mice. Systemic or hepatocyte-specific ablation of Est, or pharmacological inhibition of Est, protected female mice from ConA-induced hepatitis regardless of ovariectomy, suggesting the effect of Est inhibition was estrogen independent. In contrast, we found that hepatocyte-specific transgenic reconstitution of Est in the whole-body Est knockout (EstKO) mice abolished the protective phenotype. Upon the ConA challenge, EstKO mice exhibited a more robust inflammatory response with elevated production of proinflammatory cytokines and changed liver infiltration of immune cells. Mechanistically, we determined that ablation of Est led to the hepatic induction of lipocalin 2 (Lcn2), whereas ablation of Lcn2 abolished the protective phenotype of EstKO females. Our findings demonstrate that hepatocyte Est is required for the sensitivity of female mice to ConA-induced and T cell-mediated hepatitis in an estrogen-independent manner. Est ablation may have protected female mice from ConA-induced hepatitis by upregulating Lcn2. Pharmacological inhibition of Est might be a potential strategy for the treatment of AIH.

Discontinuation of immunosuppression in patients with immune-mediated drug-induced liver injury or idiopathic autoimmune hepatitis: A case-control study

Background and Aim

Drug-induced liver injury (DILI) may present with autoimmune features and require immunosuppressive therapy (IST) to reach biochemical response. Discontinuation of IST without hepatitis relapse may be more frequent in these patients as compared to patients with classical autoimmune hepatitis (AIH). We aimed to determine baseline characteristics and outcome of patients with immune-mediated drug induced liver injury (IMDILI) with particular emphasis on IST during follow-up.

Methods

We performed a single-center retrospective study of consecutive patients presenting at a tertiary care center between January 2005 and December 2019 either with IMDILI or with classical AIH, for whom full baseline characteristics and a close follow-up were available over a 12-month period.

Results

Overall, 31 patients (IMDILI n = 16, mean age 59 [34-74] years; AIH n = 15, mean age 47 [15-61] years) were included, showing similar biochemical, serological, and histological characteristics. Incriminating drugs in IMDILI patients were mostly represented by nonsteroidal antiinflammatory drugs and sartans. Initial corticosteroids combined with IST led to biochemical response in all patients. Compared to idiopathic AIH, more patients with IMDILI were weaned off corticosteroids at the end of follow-up (11/16 [68.7%] vs 4/15 [26.6%], P < 0.02). At 1 year of follow-up, more patients in the IMDILI group compared to the classical AIH group were off any type of IST (13/16 [81%] vs 15/15 [100%], P = 0.08).

Conclusions

Although presenting with similar baseline biochemical and histological characteristics as idiopathic AIH, patients with IMDILI may not require long-term IST.

Multi-Omics Analysis Reveals the Protection of Gasdermin D in Concanavalin A-Induced Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is a progressive inflammation-associated liver injury. Pyroptosis is a novel inflammatory programmed cell death wherein gasdermin D (GSDMD) serves as the executioner. Our work challenged Gsdmd^-/- mice with concanavalin A (ConA) to try to unveil the actual role of GSDMD in AIH. After ConA injection, Gsdmd^-/- mice exhibited more severe liver damage characterized by a lower survival rate, more extensive hepatocyte necrosis and apoptosis, and higher serum transaminase levels, indicating the protection of GSDMD in ConA-induced AIH. Furthermore, the Gsdmd^-/- mice exhibited higher hepatic expression and serum levels of inflammatory cytokines (gamma interferon [IFN-γ], tumor necrosis factor alpha [TNF-α], and interleukin-17A [IL-17A]) and more infiltration of macrophages and neutrophils after ConA treatment than did wild-type (WT) mice. Gsdmd^-/- mice with AIH showed increased hepatic l-glutamine levels but decreased glycerophospholipid metabolites levels. L-glutamine levels showed positive correlations while glycerophospholipid metabolites showed negative associations with liver injury indexes and inflammation markers. We further observed a destroyed intestinal barrier in Gsdmd^-/- mice after ConA injection as indicated by decreased transcriptional expressions of Tjp1, Ocln, Reg3g, and Muc2. ConA-treated Gsdmd^-/- mice also exhibited higher serum LPS binding protein (LBP) concentrations and hepatic Tlr4 and Cd14 mRNA levels. Further fecal 16S rRNA gene sequencing demonstrated decreased relative abundances of Lactobacillus and Roseburia but increased relative abundances of Allobaculum and Dubosiella in Gsdmd^-/- mice with AIH. Lactobacillus was negatively correlated with liver injury and inflammation indexes and positively associated with Ocln, Muc2, and Reg3g levels. Allobaculum was positively related to liver injury and inflammatory cytokines and negatively correlated with gut barrier indexes. IMPORTANCE Our study provides the first direct clues to the protective role of gasdermin D (GSDMD) in autoimmune hepatitis (AIH). We demonstrated that Gsdmd knockout exacerbated concanavalin A (ConA)-induced AIH in mice. It may be due to the destroyed intestinal barrier and changes in certain intestinal microbes and hepatic metabolites resulting in increased liver injury and inflammation in ConA-treated Gsdmd^-/- mice. This finding suggested a nonnegligible role of GSDMD in AIH and also confirmed its physiological nonpyroptosis effects on the host. The role of GSDMD in autoimmune liver diseases or other liver diseases is complex and intriguing, deserving deep investigation.

The Role of Gut Microbiota in Some Liver Diseases: From an Immunological Perspective

Gut microbiota is a microecosystem composed of various microorganisms. It plays an important role in human metabolism, and its metabolites affect different tissues and organs. Intestinal flora maintains the intestinal mucosal barrier and interacts with the immune system. The liver is closely linked to the intestine by the gut-liver axis. As the first organ that comes into contact with blood from the intestine, the liver will be deeply influenced by the gut microbiota and its metabolites, and the intestinal leakage and the imbalance of the flora are the trigger of the pathological reaction of the liver. In this paper, we discuss the role of gut microbiota and its metabolites in the pathogenesis and development of autoimmune liver diseases((including autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis), metabolic liver disease such as non-alcoholic fatty liver disease, cirrhosisits and its complications, and liver cancer from the perspective of immune mechanism. And the recent progress in the treatment of these diseases was reviewed from the perspective of gut microbiota.

Autoantibodies Associated with Autoimmune Liver Diseases in a Healthy Population: Evaluation of a Commercial Immunoblot Test

Autoantibodies constitute important tools for diagnosing the autoimmune liver diseases (AILD) autoimmune hepatitis and primary biliary cholangitis. The EUROLINE immunoblot assay, detecting multiple specificities, is widely used, but the clinical importance of weakly positive findings is unclear. The manufacturer’s recommended cut-off was evaluated by investigating AILD-associated autoantibodies in 825 blood donors and 60 confirmed AILD cases. Positive findings were followed up with immunofluorescence microscopy on rat tissue, anti-M2-ELISA, alternative immunoblot assay, and liver function tests. Thirty-six (4.4%) blood donors were positive with EUROLINE. The most common specificities were LC-1 (1.6%), gp210 (1.3%), and AMA-M2 (1.1%). In general, the positive results were higher in patients than in blood donors, whereas anti-LC-1 was higher in blood donors. The liver function tests were slightly elevated in 2 of the 36 immunoblot positive blood donors. The majority of the positive EUROLINE findings could not be confirmed with the follow-up tests. The EUROLINE-Autoimmune Liver Diseases-(IgG) immunoblot detected autoantibodies in 4.4% of blood donors without signs of AILD. Our findings indicate that the recommended cut-off can be raised for most specificities without loss of diagnostic sensitivity. The prevalence of anti-LC-1 among blood donors indicates a problem with the antigen source.

Impaired central tolerance induces changes in the gut microbiota that exacerbate autoimmune hepatitis

Medullary thymic epithelial cells (mTECs) induce T cell tolerance in the thymus through the elimination of self-reactive thymocytes. Commensal bacteria are also critical for shaping T cell responses in the gut and distal organs. We previously showed that mice depleted of mTECs (Traf6ΔTEC) generated autoreactive T cells and developed autoimmune hepatitis (AIH). In this report, we found that Toll-like receptor (TLR)-mediated microbial sensing on liver hematopoietic cells and the gut microbiota contributed to AIH development in Traf6ΔTEC mice. While adoptive transfer of thymic Traf6ΔTEC T cells in immune-deficient mice was sufficient for AIH development, colonization of germ-free mice with Traf6ΔTEC microbiota failed to induce AIH, suggesting that the gut microbiota contributes to but is not sufficient for AIH development. Microbiota-mediated exacerbation of AIH associated with increased numbers of hepatic Foxp3+ T cells and their increase was proportional to the degree of inflammation. The contribution of the gut microbiota to AIH development associated with an altered microbial signature whose composition was influenced by the qualitative nature of the thymic T cell compartment. These results suggest that aberrant selection of T cells in the thymus can induce changes in the gut microbiota that lead to exacerbation of organ-specific autoimmunity and AIH. Our results add to our understanding of the mechanisms of AIH development and create a platform towards developing novel therapeutic approaches for treating this disease.

Autoimmune Hepatitis: Serum Autoantibodies in Clinical Practice

Circulating autoantibodies are a key diagnostic tool in autoimmune hepatitis (AIH), being positive in 95% of the cases if tested according to dedicated guidelines issued by the International Autoimmune Hepatitis Group. They also allow the distinction between type 1 AIH, characterized by positive anti-nuclear and/or anti-smooth muscle antibody, and type 2 AIH, characterized by positive anti-liver kidney microsomal type 1 and/or anti-liver cytosol type 1 antibody. Anti-soluble liver antigen is the only AIH-specific autoantibody, and is found in 20-30% of both type 1 and type 2 AIH. Anti-neutrophil cytoplasmic antibody is frequently positive in type 1 AIH, being associated also with inflammatory bowel disease and with primary/autoimmune sclerosing cholangitis. The reference method for autoantibody testing remains indirect immunofluorescence on triple tissue (rodent liver, kidney and stomach), allowing both the detection of the majority of liver-relevant reactivities, including those autoantibodies whose molecular target antigens are unknown. Of note, the current knowledge of the clinical significance of autoantibodies relies on studies based on this technique. However, immunofluorescence requires trained laboratory personnel, is observer-dependent, and lacks standardization, leading to ongoing attempts at replacing this method with automated assays, the sensitivity, and specificity of which, however, require further studies before they can be used as a reliable alternative to immunofluorescence; currently, they may be used as complementary to immunofluorescence.

Autoimmune hepatitis in Egyptian children: A single center experience

Background and aim

Autoimmune hepatitis (AIH) has variable clinical manifestations and should be considered in the diagnostic work-up of any patient with cryptogenic liver disease. The aim of the study was to determine the clinical, biochemical, histopathological characteristics and treatment outcome of AIH in Egyptian children.

Patients and methods

This observational study was conducted at the Pediatric Hepatology Unit at Cairo University Pediatric Hospital, Egypt. All children (<18 years of age) presenting from 2009 to 2016 with established diagnosis of AIH were included. Medical history, clinical examination, and results of investigations were retrieved from patients’ files. The main outcome measures included the rate of remission, relapses, and mortality.

Results

The study included 34 children with AIH. Twenty patients (58%) presented with chronic liver disease. There was a history of concomitant autoimmune diseases in 5 patients. Transaminases were elevated in all patients. There was synthetic dysfunction in 58%. Twenty-four patients (70.5%) had AIH-1, while nine patients (26.4%) had AIH-2 and one patient (2.9%) had autoantibody negative AIH. Piecemeal necrosis was observed in the liver biopsy of 79% of our cohort. Approximately 80% achieved biochemical remission (88% received combined therapy of prednisolone and azathioprine). About half of the patients developed relapses. One patient died of liver cell failure.

Conclusion

In children with liver disease, a diagnosis of AIH should be considered. In those patients, AIH-1 is more common than AIH-2. Prednisolone monotherapy or combined with azathioprine could achieve remission, but relapse is still common. Treatment non-adherence is the main risk factor for relapse.

Autoimmune hepatitis in genetic syndromes: A literature review

Genetic syndromes represent relevant and rare diseases. These conditions include a large amount of epidemiological, pathogenetic and clinical features. However, a systematic approach to genetic syndromes is often prevented by the rareness of these diseases. So, although clinical features are usually precisely defined, nowadays more uncommon associations between genetic syndromes and internal medicine related diseases have been insufficiently studied. Autoimmune hepatitis (AIH) is a chronic liver disease caused by loss of tolerance to hepatocyte-specific auto-antigens. Conversely, a better knowledge about specific genetic syndromes in which AIH is more frequent could be important in the clinical management of patients, both for an early diagnosis and for a prompt therapy. Furthermore, a systematic approach could explain if onset, clinical course, and response to treatment of AIH are typical for specific genetic syndromes. We took in consideration all the scientific articles reported in PubMed in the last 10 years, from 2010 to 2020. The purpose of this review is to explore the prevalence of AIH in genetic syndrome, but also to suggest new classification, that could be useful for pathogenetic hypothesis and clinical approach to genetic syndrome. From the 139 publications selected using keywords “autoimmune hepatitis” and “genetic syndrome”, 30 papers (21.6%) respected the chosen inclusion criteria, reporting the association between AIH in patients with a genetic syndrome. We have collected in all 47 patients with AIH and genetic syndrome, and with median age of 12.6-year-old. We suggest that when a patient presents a clinical picture of cryptogenic chronic hepatitis, that is unexplained, it is useful to explore differential diagnosis of AIH associated with genetic syndrome. Given the clinical relevance of this topic, further reports are needed to demonstrate our hypothesis and collect new evidence in this field.

Stem cell therapies for autoimmune hepatitis

Autoimmune hepatitis is a chronic inflammatory hepatic disorder which may cause liver fibrosis. Appropriate treatment of autoimmune hepatitis is therefore important. Adult stem cells have been investigated as therapies for a variety of disorders in latest years. Hematopoietic stem cells (HSCs) were the first known adult stem cells (ASCs) and can give rise to all of the cell types in the blood and immune system. Originally, HSC transplantation was served as a therapy for hematological malignancies, but more recently researchers have found the treatment to have positive effects in autoimmune diseases such as multiple sclerosis. Mesenchymal stem cells (MSCs) are ASCs which can be extracted from different tissues, such as bone marrow, adipose tissue, umbilical cord, and dental pulp. MSCs interact with several immune response pathways either by direct cell-to-cell interactions or by the secretion of soluble factors. These characteristics make MSCs potentially valuable as a therapy for autoimmune diseases. Both ASC and ASC-derived exosomes have been investigated as a therapy for autoimmune hepatitis. This review aims to summarize studies focused on the effects of ASCs and their products on autoimmune hepatitis.

Case Report: Viral Pneumonia Could Prompt the Advancement of Immune-Mediated Liver Disease

Background: The impact of the influenza A (H1N1) and SARS-CoV-2 virus on the development of autoimmune hepatitis has not been described previously.

Methods: In this case series, we evaluated the dynamic changes in liver function of three patients with autoimmune hepatitis who presented with viral infection (two with the H1N1 and one with the SARS-CoV-2 virus) during the recent COVID-19 outbreak.

Result: Patient 1 was a 68-year-old woman with a history of hepatitis of unknown origin before being infected with the H1N1 virus. Autoimmune hepatitis with an exacerbation of liver injury was diagnosed during the infection. Patient 2 was a 48-year-old woman with pre-existing autoimmune hepatitis. Despite being on immunosuppressant therapy (using glucocorticoids), liver injury recurred with elevated total bilirubin and gamma-glutamyl transferase levels post H1N1 infection. Patient 3 was a 61-year-old woman with probable autoimmune hepatitis. Liver injury recurred with a flare in alanine transaminase/aspartate transaminase levels post SARS-CoV-2 infection, in spite of the patient being on liver protection therapy (using ursodeoxycholic acid).

Conclusion: The case series raises the possibility that COVID-19 or influenza induced pneumonia triggers the progression of autoimmune hepatitis.

Tim-3 suppresses autoimmune hepatitis via the p38/MKP-1 pathway in Th17 cells

T‐cell immunoglobulin‐ and mucin‐domain‐containing molecule‐3 (Tim‐3) mediates T‐cell suppression in various autoimmune diseases, such as chronic inflammatory liver disease. However, the regulatory effect of Tim‐3 on Th17 cells in autoimmune hepatitis (AIH) is incompletely understood. Here, we studied the expression and function of Tim‐3 in T cells in AIH patients and in a Con A (concanavalin A)‐induced mouse AIH model. We report that the frequency of CD4⁺Tim‐3⁺ T cells in peripheral blood samples of AIH patients was lower than that in the control group. The p38/MKP‐1 and p‐JNK pathways were activated, and the expression of interleukin‐17A protein was elevated in patients with AIH. Furthermore, the extent of pathological damage in the livers of mice with a blocked Tim‐3 signaling pathway (anti‐Tim‐3 group) was markedly increased and correlated with elevated alanine aminotransferase and aspartate aminotransferase levels. In addition, the frequency of CD4⁺ IL‐17⁺ T (Th17) cells in the anti‐Tim‐3 group was increased, while that in mice with blocked p38 activity was decreased. Finally, the expression of MKP‐1 (p‐p38) gradually increased in the control, Con A, and anti‐Tim‐3 groups, but the levels of interleukin‐17A were decreased in the p38‐blocked group. In summary, our results suggest that Tim‐3 suppresses AIH by regulating Th17 cells through the p38/MKP‐1 pathway.

Long-term outcome of patients with difficult-to-treat autoimmune hepatitis receiving mycophenolate mofetil

BACKGROUND

Most patients with autoimmune hepatitis (AIH) respond to a combination of prednisolone and azathioprine. For patients who are intolerant or refractory to azathioprine, proposed alternative therapies are based on scarce data, limited to transplant centres and with short-term follow-up periods.

OBJECTIVE

To evaluate the long-term efficacy and safety of MMF as a second-line therapy in patients with AIH managed at a tertiary non-transplant centre.

METHODS

Retrospective analysis of a prospectively collated database identified AIH patients who received MMF from 2006 to 2015. Clinical, biochemical and immunological parameters were assessed at 3-, 6- and 12-months, and at last follow-up. Biochemical response (BR) was defined as improvement of transaminases, complete remission (CR) as normalisation of transaminases and IgG, while others were considered non-responders (NR).

RESULTS

Eighteen out of 151 (12%) AIH patients received MMF. Nine received MMF due to azathioprine-intolerance (group 1), while nine due to refractory disease (group 2). In group 1, CR and BR was achieved in six (67%) and two (22%) patients respectively. In group 2, CR and BR was achieved in one (11%) and five (56%) patients respectively. Adverse events occurred in eight patients (44%), with one patient requiring drug discontinuation. After a medium follow-up of 78 (31-116) months, there was a significant decrease in transaminase levels, mirrored by decrease in prednisolone dose from 25 to 6.25 mg/day (P<0.05).

CONCLUSION

Long-term therapy with MMF is safe and effective in AIH patients requiring second-line therapies, and these patients can be effectively managed at tertiary non-liver transplant centres.

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.

Autoantibodies associated with primary biliary cholangitis are common among patients with systemic lupus erythematosus even in the absence of elevated liver enzymes

Knowledge of concomitant autoimmune liver diseases (AILD) is more detailed in primary Sjögren's syndrome (pSS) compared to systemic lupus erythematosus (SLE). Herein, the prevalence of autoantibodies associated with autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) was investigated in stored sera from patients with SLE (n = 280) and pSS (n = 114). Antibodies against mitochondria (AMA), liver-kidney microsomal (LKM) antigen, smooth muscle (SMA) and anti-nuclear antibodies (ANA) were analysed with immunofluorescence microscopy. In addition, AILD-associated autoantibodies were tested with immunoblot. Prior to sampling, eight SLE (2·9%) and three pSS (2·6%) cases were diagnosed with AILD. Among SLE-cases without known AILD (n = 272), 26 (9·6%) had PBC-associated autoantibodies, 15 (5·5%) AIH-associated autoantibodies (excluding ANA) and one serological overlap. Most subjects with PBC-associated autoantibodies had liver enzymes within reference limits (22 of 27, 81%) or mild laboratory cholestasis (two of 27, 7·4%), while one fulfilled the diagnostic PBC-criteria. AMA-M2 detected by immunoblot was the most common PBC-associated autoantibody in SLE (20 of 272, 7·4%). The prevalence of SMA (4·4%) was comparable with a healthy reference population, but associated with elevated liver enzymes in four of 12 (25%), none meeting AIH-criteria. The patient with combined AIH/PBC-serology had liver enzymes within reference limits. Among pSS cases without known AILD (n = 111), nine (8·1%) had PBC-associated, 12 (10·8%) AIH-associated autoantibodies and two overlapped. PBC-associated autoantibodies were found as frequently in SLE as in pSS but were, with few exceptions, not associated with laboratory signs of liver disease. Overall, AILD-associated autoantibodies were predominantly detected by immunoblot and no significant difference in liver enzymes was found between AILD autoantibody-negative and -positive patients.

Clinical characteristics of paediatric autoimmune hepatitis at a referral hospital in Sub Saharan Africa

BACKGROUND

Autoimmune hepatitis (AIH) is a progressive inflammatory liver disease of unknown aetiology. The number of reported AIH cases is increasing in the developed countries but the same cannot be said about sub Saharan Africa (SSA). Paediatric AIH diagnosis is usually missed and patients present with decompensated liver disease. Our study highlights the clinical profile of paediatric AIH cases at a referral hospital in Ghana.

METHODS

This is a retrospective review of all cases of children diagnosed with autoimmune hepatitis at the gastroenterology clinic in Korle Bu Teaching Hospital, Accra, Ghana. Data was extracted from the patients' records from April 2016 to October 2019. These children were diagnosed based on the presence of autoantibodies, elevated immunoglobulin G and histologic presence of interphase hepatitis with the exclusion of hepatitis A, B, C and E depending on their clinical presentation, Wilson's disease, HIV, Schistosomiasis and sickle cell disease.

RESULTS

Thirteen patients aged between 5 years to 13 years with a mean age of 10 years were diagnosed with AIH. All the patients had type 1 AIH with majority 8 (61.5%) being females. Most of the children presented with advanced liver disease with complications. Three patients had other associated autoimmune diseases. The patients were treated with prednisolone with or without azathioprine depending on the severity of the liver disease.

CONCLUSION

Majority of paediatric AIH presents with advanced liver disease. There is the need for early detection to change the natural history of AIH in SSA.

Animal Models of Autoimmune Liver Diseases: a Comprehensive Review

Autoimmune liver diseases (AILDs) are potentially life-threatening chronic liver diseases which include autoimmune hepatitis, primary biliary cholangitis, primary sclerosing cholangitis, and recently characterized IgG4-related sclerosing cholangitis. They are caused by immune attack on hepatocytes or bile ducts, with different mechanisms and clinical manifestations. The etiologies of AILDs include a susceptible genetic background, environment insults, infections, and changes of commensal microbiota, but remain complicated. Understanding of the underlying mechanisms of AILDs is mandatory for early diagnosis and intervention, which is of great importance for better prognosis. Thus, animal models are developed to mimic the pathogenesis, find biomarkers for early diagnosis, and for therapeutic attempts of AILDs. However, no animal models can fully recapitulate features of certain AILD, especially the late stages of diseases. Certain limitations include different living condition, cell composition, and time frame of disease development and resolution. Moreover, there is no IgG4 in rodents which exists in human. Nevertheless, the understanding and therapy of AILDs have been greatly advanced by the development and mechanistic investigation of animal models. This review will provide a comprehensive overview of traditional and new animal models that recapitulate different features and etiologies of distinct AILDs.

Frequency of OBI among Patients with Autoimmune Hepatitis

Autoimmune hepatitis (AIH) is recognized as a serious disease in which the body’s immune system attacks liver cells so untreated patients may consequently suffer from liver cirrhosis, hepatocellular carcinoma (HCC) and liver failure. The role of viral infection may be involved in AIH. Presence of anti-HBc alone is a predictive signal of potential OBI. Thus, this study was conducted to evaluate the rate OBI among the patients with AIH.

Histopathological analysis of autoimmune hepatitis with "acute" presentation: Differentiation from drug-induced liver injury

AIM

Presently, no standardized definition or acceptable diagnostic criteria have been established for acute presentation of autoimmune hepatitis (AP-AIH), making it difficult to differentiate that condition from drug-induced liver injury (DILI). This study aimed to characterize clinical and histological features for distinguishing between AP-AIH and DILI.

METHODS

Clinical, biochemical, and histological characteristics of AP-AIH and DILI in clinically well-characterized cases were compared in a standardized manner to clarify differences.

RESULTS

In clinical evaluations, immunoglobulin G level and rate of anti-nuclear antibody positivity were greater in AP-AIH than DILI cases. As for diagnosis of each condition, significant (P < 0.01) differences were found for 10 features: lobular necrosis/inflammation, cobblestone appearance of hepatocytes, plasma cell infiltration in liver parenchyma, centrilobular fibrosis, hepatic rosette formation in areas with cobblestone appearance, portal inflammation, interface hepatitis, prominent plasma cells in portal areas, bile duct injury, and hepatic rosette formation in periportal areas. The area under the curve and cut-off values for the combination of these 10 features were 0.95 and 9 (sensitivity 86%, specificity 90%), respectively.

CONCLUSION

Combinations of histological features were found to be helpful for differentiating AP-AIH from DILI, but we were not able to statistically identify an individual feature as definitive.

Rescue of autoimmune hepatitis by soluble MHC class II molecules in an altered concanavalin A-induced experimental model

BACKGROUND

Soluble major histocompatibility complex class II (sMHCII) molecules have been described to maintain tolerance through the suppression of autoreactive T lymphocytes. In order to evaluate their ability to rescue autoimmune hepatitis (AIH) symptoms, the present work attempted to administer sMHCII molecules to an in vitro as well as in vivo concanavalin A (ConA)-induced AIH model.

METHODS

The in vitro AIH model consisted of splenocyte stimulation with ConA in the presence or absence of serum-isolated sMHCII molecules. An in vivo ConA-modified model with or without sMHCII treatment was developed. The cytokine profile in culture supernatants and serum was tested by ELISA. Cell markers were evaluated by immunofluorescence, while cell proliferation by tritiated thymidine uptake. AIH symptoms were assessed by daily observations for the establishment of a disease severity scoring system and liver histology was evaluated using a biomolecular imager.

RESULTS

The presence of sMHCII molecules in the ConA-stimulated cell cultures leads to a significant reduction of cell proliferation. The administration of sMHCII molecules to the ConA-treated animals showed a significant reduction in the levels of IL-2, IL-4, and IL-10, as well as a decrease in the number of spleen CD4+ and CD8+ cells. Upon development of a scoring system, it was shown that the sMHCII treatment was accompanied by a slower progression of the disease, while rescuing fibrotic liver morphology.

CONCLUSION

The results presented in this study confirm the ability of sMHCII proteins to alleviate autoimmune hepatitis, possibly highlighting new therapeutic approaches for autoimmune diseases.

Hepatocytes paradoxically affect intrahepatic IFN-γ production in autoimmune hepatitis due to Gal-9 expression and TLR2/4 ligand release

Hepatocytes are the targets in autoimmune hepatitis (AIH) that results in T cell-dependent liver injury. However, hepatocytes may also affect the hepatic T cells in AIH, but the underlying mechanisms are not fully understood. Here we report that hepatocytes could secrete galectin-9 (Gal-9) to suppress the intrahepatic production of Th1 cytokine IFN-γ and restrict AIH development, but hepatocyte damage resulted in opposite effects due to release of TLR2/4 ligands that promoted the intrahepatic production of IL-1β, IL-6, and IL-12. Through Tim-3, Gal-9 could efficiently suppress the intrahepatic T cell activation despite presence of TLR2/4 ligands, thus attenuating Th1 response in AIH. Intriguingly, intrahepatic IL-6/IL-12 suppressed the effect of TGF-β on Treg cells. Therefore, in AIH, Gal-9 promoted Foxp3 expression and function of hepatic Treg cells through TL1A signaling, although Treg function was still impaired, compared with that in naive state. Due to its promoting effect on Treg function, together with its effect on T effector cells in a Tim-3-independent way, Gal-9 could attenuate intrahepatic IFN-γ production by hindering the increase of hepatic CD4⁺CD43⁺ T cells resulting from extrahepatic T cell activation. TLR2/4 ligands attenuated the effects of Gal-9 on Treg cells and CD4⁺CD43⁺ T cells by increasing intrahepatic IL-6 and IL-12. Blocking TLR2/4 ligands could efficiently suppress intrahepatic IFN-γ production, liver injury, and hepatic fibrosis. These findings suggest that hepatocytes paradoxically affect Th1 response in AIH due to Gal-9 expression and TLR2/4 ligands release, and that targeting TLR2/4 signaling may provide an important approach in the therapeutic strategy for AIH.

Soluble PD1 levels are increased with disease activity in paediatric onset autoimmune hepatitis and inflammatory bowel disease

Introduction: Immune mediated liver diseases entail a broad category which are associated with increased morbidity and mortality amongst the paediatric population. Programmed Death 1 (PD1) is an inhibitory receptor mainly expressed by T cells, and when activated shed into plasma as soluble PD1(sPD1). The AIM of this study was to evaluate sPD1 levels in plasma of paediatric patients with Autoimmune Hepatitis (AIH), Primary Sclerosing Cholangitis (PSC), AIH and PSC overlap, Inflammatory Bowel Disease (IBD) alone, and concurrent PSC/IBD and AIH/IBD in order to identify a biomarker to response or predict relapse verses remission.Methods: Plasma samples were collected from 41 paediatric patients. AIH patients were further categorized into active, incomplete responders and responders, based on response to standard therapy. sPD1 levels were measured and compared between PSC, PSC/AIH, IBD alone, PSC/IBD and AIH/IBD patients and between active AIH, incomplete responders and responders. Flow cytometry was performed to further analyze CD45RA+, CD3CD4, CD8, CCR7, CXCR3, CD38 and PD1.Results: In the AIH group, those with active disease demonstrated a significantly higher sPD1 levels in comparison to responders (*p > .001). However, the incomplete responders didn't show a reduction in sPD1 in comparison to active AIH and patients with IBD alone. Interestingly, patients with PSC showed significantly lower level of sPD1 compared to active AIH (*p < .002), whereas, patients with PSC in conjunction with AIH (*p < .006) or IBD (*p < .02) demonstrated a significant increase in sPD1. In addition, we have observed increased levels of circulating CD4 and CD8 bound PD1 in active AIH but not in PSC or responders suggesting T cells activation. CD4+ PD1 double positive cells demonstrated increased expression of CXCR3. Thus, suggesting the activation of PD1 + T cells is mediating through CXCR3 in Autoimmune hepatitis.Conclusions: Our study demonstrates that sPD1 levels correlate with active disease state of AIH and IBD. sPD1 levels did not correlate with PSC. However, PSC in conjunction with AIH or IBD showed higher levels of sPD1. This suggests that T cell activation plays a critical role in active AIH and IBD but not in PSC. Soluble PDI levels could be used as a clinical biomarker to assess response in patients with AIH and for prospectively monitoring PSC patients for development of IBD or AIH.

Viral Hepatitis and Iron Dysregulation: Molecular Pathways and the Role of Lactoferrin

The liver is a frontline immune site specifically designed to check and detect potential pathogens from the bloodstream to maintain a general state of immune hyporesponsiveness. One of the main functions of the liver is the regulation of iron homeostasis. The liver detects changes in systemic iron requirements and can regulate its concentration. Pathological states lead to the dysregulation of iron homeostasis which, in turn, can promote infectious and inflammatory processes. In this context, hepatic viruses deviate hepatocytes' iron metabolism in order to better replicate. Indeed, some viruses are able to alter the expression of iron-related proteins or exploit host receptors to enter inside host cells. Lactoferrin (Lf), a multifunctional iron-binding glycoprotein belonging to the innate immunity, is endowed with potent antiviral activity, mainly related to its ability to block viral entry into host cells by interacting with viral and/or cell surface receptors. Moreover, Lf can act as an iron scavenger by both direct iron-chelation or the modulation of the main iron-related proteins. In this review, the complex interplay between viral hepatitis, iron homeostasis, and inflammation as well as the role of Lf are outlined.

Immunopathogenesis of Autoimmune Hepatitis

http://aasldpubs.onlinelibrary.wiley.com/hub/journal/10.1002/(ISSN)2046-2484/video/15-3-reading-assis a video presentation of this article http://aasldpubs.onlinelibrary.wiley.com/hub/journal/10.1002/(ISSN)2046-2484/video/15-3-interview-assis the interview with the author.

Phytosterols of marine algae: Insights into the potential health benefits and molecular pharmacology

BACKGROUND

Marine algae are rich in some unique biologically active secondary metabolites having diverse pharmacological benefits. Of these, sterols comprise a group of functional lipid compounds that have attracted much attention to natural product scientists.

PURPOSE

This review was aimed to update information on the health effects of algae-derived phytosterols and their molecular interactions in various aspects of human health and diseases and to address some future perspectives that may open up a new dimension of pharmacological potentials of algal sterols.

METHODS

A literature-based search was carried out to retrieve published research information on the potential health effects of algal phytosterols with their pharmacological mechanisms from accessible online databases, such as Pubmed, Google Scholar, Web of Science, and Scopus, using the key search terms of 'marine algae sterol' and 'health potentials such as antioxidant or anti-inflammatory or anti-Alzheimer's or anti-obesity or cholesterol homeostasis or hepatoprotective, antiproliferative, etc.'

RESULTS

Phytosterols of marine algae, particularly fucosterol, have been investigated for a plethora of health benefits, including anti-diabetes, anti-obesity, anti-Alzheimer's, antiaging, anticancer, and hepatoprotection, among many others, which are attributed to their antioxidant, anti-inflammatory, immunomodulatory and cholesterol-lowering properties, indicating their potentiality as therapeutic leads. These sterols interact with enzymes and various other proteins that are actively participating in different cellular pathways, including antioxidant defense system, apoptosis and cell survival, metabolism, and homeostasis.

CONCLUSION

In this review, we briefly overview the chemistry, pharmacokinetics, and distribution of algal sterols, and provide critical insights into their potential health effects and the underlying pharmacological mechanisms, beyond the well-known cholesterol-lowering paradigm.

Hepatic ILC2 activity is regulated by liver inflammation-induced cytokines and effector CD4+ T cells

In immune-mediated hepatitis, type 2 innate lymphoid cells (ILC2) as well as effector CD4⁺ T cells have been shown to drive disease pathology. However, less is known about mechanisms involved in the regulation of ILC2 function during liver inflammation. We showed that in homeostasis, hepatic ILC2 constituted a very small population with a naive, inactive phenotype. During immune-mediated hepatitis, the cytokines IL-33 and IFNγ were expressed in liver tissue. IL-33 induced strong activation and expression of type 2 cytokines as well as IL-6 by hepatic ILC2 while IFNγ suppressed cytokine production. Interestingly, this inhibitory effect was overcome by IL-33. The phenotype of activated hepatic ILC2 were stable since they did not show functional plasticity in response to liver inflammation-induced cytokines. Moreover, hepatic ILC2 induced a Th2 phenotype in activated CD4⁺ T cells, which increased ILC2-derived cytokine expression via IL-2. In contrast, Th1 cells inhibited survival of ILC2 by production of IFNγ. Thus, hepatic ILC2 function is regulated by IL-33, IL-2, and IFNγ. While IL-33 and IL-2 support hepatic ILC2 activation, their inflammatory activity in immune-mediated hepatitis might be limited by infiltrating IFNγ-expressing Th1 cells.

Red blood cell distribution width for predicting significant liver inflammation in patients with autoimmune hepatitis

BACKGROUND

Red blood cell distribution width (RDW) was reported to be associated with the severity of liver diseases. We aimed to investigate the association between RDW and severity of liver inflammation in autoimmune hepatitis (AIH).

PATIENTS AND METHODS

Ninety-two consecutive AIH patients who underwent liver biopsy during 2016-2017 were included. Liver histology was evaluated using the Scheuer scoring system. Logistic regression analysis was used to analyze the risk factors for significant inflammation. The diagnostic accuracy was evaluated by the area under the receiver operating characteristic curve.

RESULTS

The RDW level was higher in AIH patients with significant inflammation (14.6%, interquartile range: 13.2-16.3%) than in patients with mild inflammation (13.2%, interquartile range: 12.6-13.8%). The RDW level was correlated positively with the grades of liver inflammation (r=0.356, P < 0.001). The area under the receiver operating characteristic curve of RDW in predicting significant inflammation was 0.739 (95% confidential interval: 0.634-0.843, P < 0.001), with 67.80% sensitivity and 75.76% specificity. The diagnostic performance of RDW for significant inflammation was better than alanine aminotransferase (P = 0.003) and immunoglobulin G (P = 0.049). RDW (odds ratio = 1.702, P = 0.001) was identified as an independent predictor for significant inflammation by logistic multivariable analysis.

CONCLUSION

The RDW level was correlated positively with the severity of liver inflammation in AIH patients. RDW can be a promising indicator for predicting significant liver inflammation in AIH.

Effects of adenovirus-induced hepatocyte damage on chronic bile duct inflammation in a sclerosing cholangitis mouse model

BACKGROUND & AIMS

Four major autoimmune diseases target the liver. They develop because of bile duct destruction, leading to chronic cholestasis or result from hepatocyte damage like autoimmune hepatitis (AIH). Interestingly, some patients simultaneously show features of both cholangitis and AIH. Our goal was to mimic such concurrent characteristics in a mouse model that would help deciphering mechanisms possibly involved in an inflammatory crosstalk between cholestatic disease and hepatitis.

METHODS

Mdr2^-/- mice, which spontaneously develop sclerosing cholangitis because of accumulation of toxic bile salts, were infected with adenovirus (Ad) encoding human Cytochrome P4502D6 (hCYP2D6), the major target autoantigen in type-2 AIH, to trigger hepatocyte injury. Wild type FVB mice were controls.

RESULTS

Resulting Ad-Mdr2^-/- mice presented with cholangitis, fibrosis and cellular infiltrations that were higher than in Mdr2^-/- or Ad-FVB mice. Increased levels of anti-neutrophil cytoplasmic antibodies but similar anti-hCYP2D6 antibody titres were detected in Ad-Mdr2^-/- compared to Mdr2^-/- and Ad-FVB mice respectively. IFNγ-expressing hCYP2D6-specific CD4 T cells declined, whereas hCYP2D6-specific CD8 T cells increased in Ad-Mdr2^-/- compared to Ad-FVB mice. The overall T cell balance in Ad-Mdr2^-/- mice was a combination of a type 17 T cell response typically found in Mdr2^-/- mice with a type 1 dominated T cell response characteristic for Ad-FVB mice. Simultaneously, the type 2 T cell compartment was markedly reduced.

CONCLUSIONS

Experimental hepatitis induction in a mouse with sclerosing cholangitis results in a disorder which represents not simply the sum of the individual characteristics but depicts a more complex entity which urges on further analysis.

Hepatic expression of programmed death-1 (PD-1) and its ligand, PD-L1, in children with autoimmune hepatitis: relation to treatment response

AIM OF THE STUDY

Autoimmune hepatitis (AIH) is characterized histologically by aggressive inflammation with interface hepatitis and prominent lymphoplasmacytic infiltration. Programmed death-1 (PD-1) is expressed on activated lymphocytes. Engagement of PD-1 by its ligand PD-L1 leads to cell apoptosis and death. We aimed to evaluate the immunohistochemical expression of PD-1 and PD-L1 in children with AIH, and its relation to treatment outcome.

MATERIAL AND METHODS

Pre-treatment liver biopsies of 31 children with AIH were compared to 30 children with chronic hepatitis C virus (HCV) infection as a control group. PD-1 was evaluated in lymphocytes, while PD-L1 was evaluated in lymphocytes, hepatocytes, biliary epithelial cells, sinusoidal endothelial cells and Kupffer cells. All AIH patients received the standard treatment.

RESULTS

The mean PD-1 was significantly higher in AIH than HCV patients (29.19 ±18.5% vs. 15.2 ±10.1%; p = 0.002) while there was no statistically significant difference as regards PD-L1 on lymphocytes (p = 0.853). Neither PD-1 nor PD-L1 correlated with either liver fibrosis or the inflammatory activity (p > 0.05 for all). PD-1/PD-L1 ratio was significantly higher in AIH compared to HCV patients and in non-responder AIH patients compared to responders (46.9 vs. 6.58). PD-1 expression was comparable in both responders and non-responders (p = 0.813), while PD-L1 was significantly upregulated in responders (4.17 ±3.15% vs. 0.63 ±1.3%; p = 0.046). PD-L1 expression on hepatocytes, biliary epithelial cells, sinusoidal endothelial cells and Kupffer cells was comparable in AIH and HCV groups.

CONCLUSIONS

PD-1/PD-L1 ratio, which reflects immune aggression, was significantly higher in AIH compared to HCV patients and in non-responder AIH patients compared to responders.

Bystander activation and autoimmunity

The interaction over time of genetic, epigenetic and environmental factors (i.e., autoimmune ecology) increases or decreases the liability an individual would have to develop an autoimmune disease (AD) depending on the misbalance between risk and protective effects. Pathogens have been the most common antecedent events studied, but multiple other environmental factors including xenobiotic chemicals, drugs, vaccines, and nutritional factors have been implicated into the development of ADs. Three main mechanisms have been offered to explain the development of autoimmunity: molecular mimicry, epitope spreading, and bystander activation. The latter is characterized by auto-reactive B and T cells that undergo activation in an antigen-independent manner, influencing the development and course of autoimmunity. Activation occurs due to a combination of an inflammatory milieu, co-signaling ligands, and interactions with neighboring cells. In this review, we will discuss the studies performed seeking to define the role of bystander activation in systemic and organ-specific ADs. In all cases, we are cognizant of individual differences between hosts and the variable latency time for clinical expression of disease, all of which have made our understanding of the etiology of loss of immune tolerance difficult and enigmatic.

Comparison of mycophenolate mofetil with standard treatment for autoimmune hepatitis: a meta-analysis

OBJECTIVE

To systematically evaluate the efficacy of mycophenolate mofetil (MMF) compared with the standard treatment for autoimmune hepatitis.

METHODS

Medline (PubMed), Embase, and Cochrane Library databases were searched between 1966 and June 2018 for studies on prednisone and/or azathioprine/mycophenolate mofetil in autoimmune hepatitis. The keywords and descriptor terms used were 'hepatitis', 'autoimmunity', 'prednisone', 'prednisolone', 'azathioprine', and 'mycophenolate mofetil'. The Z test and Cochrane Q test were used in the statistical analysis.

RESULTS

Seven hundred and eighty-eight related articles were found; 779 studies were excluded after further review. Ultimately, seven studies (583 participants) were included. The remission rate of aminotransferase and immunoglobulin (Ig)-G levels with standard treatment was 33.33-86.67%, and the nonresponse rate was 15.15-66.67%. Although the remission rate of the aminotransferase level with prednisone and MMF was 55.17-88.89% and that of the IgG level was 61.16-88.89%, the nonresponse rate was 6.42-33.33%. Remission rates of the aminotransferase level (P<0.05, I=49%) and IgG level (P<0.01, I=0) with MMF were superior to those of standard treatment, and the nonresponse rate was lower (P<0.01, I=0). For those with no response to the standard treatment who were switched to MMF, the remission rates were 0, 13.33, 22.22, 25, and 34.04%. Sequential treatment with MMF was effective (P<0.01, I=90%).

CONCLUSION

Compared with the standard treatment, the combination of prednisone and MMF as a first-line treatment enables patients with autoimmune hepatitis to obtain higher remission rates of aminotransferase and IgG levels and a lower nonresponse rate. The validity and safety of long-term MMF use needs investigated further.

Therapeutic plasma exchange and a double plasma molecular absorption system in the treatment of thyroid storm with severe liver injury: A case report

BACKGROUND

Thyroid storm is resistant to conventional treatments including antithyroid drugs and ¹³¹I therapeutic means. Plasma exchange (PE) and double plasma molecular absorption system (DPMAS) can be used as an effective treatment for thyroid storm with severe liver injury.

CASE SUMMARY

A 52-year-old woman presented with a 10-day history of nausea and vomiting accompanied by yellowing of the skin and mucosa. Further, her free T3 (FT3) and FT4 levels were significantly elevated, whereas her thyrotropin level was reduced. After admission, her condition continued to deteriorate, and she presented with continued high fever, vomiting, palpitation, and shortness of breath. After being diagnosed with thyroid storm, the patient was immediately treated with PE combined with DPMAS. Her symptoms improved immediately. After three PE + DPMAS treatments, and she was discharged from the hospital. She was treated with methylprednisolone and methylthimidazole. After six months, the patient spontaneously discontinued methylthimidazole treatment. Her previous clinical manifestations and liver dysfunction reoccurred. The patient was treated with PE + DPMAS two times, and her condition rapidly improved. Liver histopathology indicated immunological liver injury.

CONCLUSION

Our experience suggests that PE combined with DPMAS can effectively relieve the development of thyroid storm.

Rheumatologic manifestations of hepatic diseases

The course of hepatic diseases may be complicated by a multitude of rheumatologic manifestations, which can complicate the diagnostic approach and alter the natural history of primary liver disease, sometimes worsening prognosis due to associated multiple organ dysfunction. These manifestations can occur in association with a multitude of liver diseases, including viral hepatitis, autoimmune hepatitis, alcoholic liver disease, nonalcoholic fatty liver disease, hemochromatosis, or Wilson’s disease. It is necessary not only for rheumatologists, but also for other clinicians, to be aware that these atypical manifestations may reflect an undiagnosed hepatic disease. On the other hand, it is crucial that, in a patient with known hepatic disease presenting with rheumatologic symptoms, an accurate distinction be made between the rheumatologic manifestations of hepatic disease and primary rheumatologic disease, since the treatment is often different. This review aims to summarize the current evidence regarding rheumatologic manifestations of hepatic diseases, how to distinguish them from primary rheumatologic disorders, and how to provide adequate management.

Fas, FasL and Foxp3 gene expression in post-liver transplant autoimmune hepatitis patients with and without acute rejection

Aim of the study

In this study we investigated Fas, FasL and Foxp3 expression in relation to liver graft rejection and its severity in autoimmune hepatitis (AIH) patients.

Material and methods

Twenty-three AIH patients including five post-transplant patients with acute rejection (AR) and 18 patients without AR (non-AR) were studied for Fas, FasL and Foxp3 gene expression in peripheral blood mononuclear cells on days 1, 3 and 7 after transplantation by real-time PCR. The relationships between gene expression and clinical features were determined.

Results

Real-time PCR showed various Fas gene expression levels with no significant difference between the days in AR patients (p = 0.52). In non-AR patients, Fas level increased from 0.98 ±0.24 fold on the first day to 1.89 ±0.42 fold on day 3 after transplantation (p < 0.01). In this group of patients, we also found a significant increase in FasL expression on day 7 (29.91 ±6.89 fold) compared to day 1 (13.50 ±7.44 fold, p < 0.05). Foxp3 gene expression in both groups showed decreased levels during the first week after transplantation. The decreased Foxp3 expression in AR patients was correlated with rejection activity index (r = 0.86, p < 0.0001).

Conclusions

Increased Fas and FasL gene expression levels in non-AR patients and decreased Foxp3 gene expression in both groups suggested the important role of these molecules in the alloreactive response after liver transplantation in AIH patients. Foxp3 expression might be useful for monitoring rejection severity.

Cellular and Molecular Mechanisms of Autoimmune Hepatitis

Autoimmune hepatitis is an uncommon idiopathic syndrome of immune-mediated destruction of hepatocytes, typically associated with autoantibodies. The disease etiology is incompletely understood but includes a clear association with human leukocyte antigen (HLA) variants and other non-HLA gene variants, female sex, and the environment. Pathologically, there is a CD4+ T cell-rich lymphocytic inflammatory infiltrate with variable hepatocyte necrosis and subsequent hepatic fibrosis. Attempts to understand pathogenesis are informed by several monogenetic syndromes that may include autoimmune liver injury, by several drug and environmental agents that have been identified as triggers in a minority of cases, by human studies that point toward a central role for CD4+ effector and regulatory T cells, and by animal models of the disease. Nonspecific immunosuppression is the current standard therapy. Further understanding of the disease's cellular and molecular mechanisms may assist in the design of better-targeted therapies, aid the limitation of adverse effects from therapy, and inform individualized risk assessment and prognostication.