B cells in autoimmune hepatitis: bystanders or central players?

A Closer Look into Autoimmune Liver Diseases

Autoimmune liver diseases involve a heterogeneous group of chronic inflammatory disorders, including autoimmune hepatitis, primary biliary cholangitis, and primary sclerosing cholangitis. Sometimes presented consistently as an overlapping syndrome, their pathogenesis is rather complex and has yet to be fully elucidated, despite extensive research efforts. This review article corroborates the molecular mechanisms of autoimmune liver diseases, as well as existing and potential therapeutic modalities.

Autoimmune hepatitis: Towards a personalized treatment

Autoimmune hepatitis is an uncommon condition that affects both adults and children and is characterized by chronic and recurrent inflammatory activity in the liver. This inflammation is accompanied by elevated IgG and autoantibody levels. Historically, treatment consists of steroids with the addition of azathioprine, which results in remission in approximately 80% of patients. Despite significant advancements in our understanding of the immune system over the past two decades, few modifications have been made to treatment algorithms, which have remained largely unchanged since they were first proposed more than 40 years ago. This review summarized the various treatment options currently available as well as our experiences using them. Although steroids are the standard treatment for induction therapy, other medications may be considered. Cyclosporin A, a calcineurin inhibitor that decreases T cell activation, has proven effective for induction of remission, but its long-term side effects limit its appeal for maintenance. Tacrolimus, a drug belonging to the same family, has been used in patients with refractory diseases with fewer side effects. Sirolimus and everolimus have interesting effects on regulatory T cell populations and may become viable options in the future. Mycophenolate mofetil is not effective for induction but is a valid alternative for patients who are intolerant to azathioprine. B cell-depleting drugs, such as rituximab and belimumab, have been successfully used in refractory cases and are useful in both the short and long term. Other promising treatments include anti-tumor necrosis factors, Janus kinases inhibitors, and chimeric antigen receptor T cell therapy. This growing armamentarium allows us to imagine a more tailored approach to the treatment of autoimmune hepatitis in the near future.

Cyclophosphamide in refractory autoimmune hepatitis and autoimmune hepatitis coexisting extrahepatic autoimmune disorders

INTRODUCTION AND OBJECTIVES

Despite tacrolimus (TAC) or mycophenolate mofetil (MMF) for alternate approaches, a proportion of patients still required further exploration of other therapeutic options due to uncontrolled autoimmune hepatitis(AIH). The role of cyclophosphamide (CYC) for AIH has been explored in isolated case reports and small series. We present a review of CYC therapy in AIH patients.

MATERIALS AND METHODS

A search for studies with keywords 'autoimmune hepatitis' and 'cyclophosphamide' was performed. Data recorded included gender, age, laboratory parameters and histological findings at the time of AIH diagnosis and before initiation of CYC therapy.

RESULTS

We identified 13 patients across 7 studies who met criteria for study inclusion, of whom around 69.2% (9/13) were primary refractory; 30.8% (4/13) patients used CYC as rescue therapy due to their coexisting autoimmune complications. The main findings of the study were that CYC appears to have an acceptable safety profile in difficult-to-treat AIH patients, with an overall remission rate of 88.9% (8/9). The other four patients with AIH accompanied by extrahepatic autoimmune disorders also achieved remission of transaminase levels and stability of liver function after the addition of CYC. A positive response to CYC treatment was seen in 12(92.3%) patients and none of them relapsed during the follow-up.

CONCLUSIONS

We cautiously recommend that CYC could be a conditioning alternative to starting second-line therapy after unsuccessful intensification of first-line treatment. Pharmacogenetic methods may play a role in guiding cyclophosphamide therapy. Given our small sample size, results should be considered preliminary.

Unmet needs in autoimmune hepatitis: Results of the prospective multicentre European Reference Network Registry (R-LIVER)

BACKGROUND AND AIMS

The European Reference Network on Hepatological Diseases (ERN RARE-LIVER) launched the prospective, multicentre, quality-controlled R-LIVER registry on rare liver diseases. The aim of this study was to assess the presentation and outcome of autoimmune hepatitis (AIH) after 1 year of treatment.

METHODS

Data were prospectively collected at the time of diagnosis and after 6 and 12 months follow-up. Complete biochemical response (CBR) was defined as normalization of alanine aminotransferase (ALT) and immunoglobulin G (IgG) serum levels.

RESULTS

A total of 231 patients from six European centres were included in the analysis. After 6 months of treatment 50% (106/212), and after 12 months 63% (131/210) of patients reached CBR with only 27% (56/211) achieving a steroid-free CBR within the first year. Overall, 16 different treatment regimens were administered. Change of treatment, mostly due to intolerance, occurred in 30.4% within the first 6 months. In multivariate analysis, younger age at diagnosis (odds ratio [OR] = 1.03 [95% confidence interval (CI) 1.01-1.05]; p = .007), severe fibrosis (OR .38 [95% .16-.89], p = .026) and change of treatment within the first 6 months (OR .40 [95% CI .2-.86]; p = .018) were associated with a lesser chance of ALT normalization at 12 months follow-up.

CONCLUSION

The landscape of AIH treatment in Europe is highly heterogeneous, even between expert centres. The results from this first European multicentre prospective registry reveal several unmet needs, highlighted by the overall low rates of CBR and the frequent failure to withdraw corticosteroids.

Autoimmune hepatitis: Current and future therapies

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease that can lead to cirrhosis and liver failure. AIH can present in all ages, races, and ethnicities, but it predominantly affects women. As a heterogeneous disease, AIH presents variably in different patients, making diagnosis and treatment a challenge. Currently, the standard treatment for AIH comprises immunosuppressants; however, their long-term use is associated with adverse effects. The pathogenesis of AIH is complex, involving T cells, macrophages, and plasma cells that invade the periportal parenchyma and lead to an inflammatory cascade that can result in liver damage. Due to the complexity of AIH pathogenesis, treatment targets several inflammatory pathways. However, unlike other autoimmune diseases in which targeted treatments have been approved, there has been little progress made in advancing the treatment paradigm for AIH. Major obstacles to progress include challenges in conducting clinical trials, particularly patient recruitment and ensuring a diverse range of backgrounds; poorly defined outcomes to assess treatment response and improved quality of life; and a lack of study designs that account for the stage of disease and variations in treatment. A focus on individualized and steroid-free treatment approaches is needed to improve AIH prognosis and minimize steroid-associated adverse effects.

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.

Research gaps and opportunities in autoimmune hepatitis-Results of the international autoimmune hepatitis group research workshop 2022

Autoimmune hepatitis (AIH) is a rare autoimmune liver disease that is characterised by a chronic inflammatory immune reaction directed against hepatocytes. The disease results in a substantial reduction in quality of life and potentially leads to liver-related complications or death. The International Autoimmune Hepatitis Group (IAIHG) initiated a series of research workshops to uncover the scientific gaps and opportunities in AIH. This review summarises the results of the latest workshop in Maastricht in 2022 and reviews the current challenges in adult AIH, particularly in relation to four important aspects of AIH: diagnostics; new immunomodulatory therapies; clinical trial design; and unmet clinical needs. This review also summarises the progress made since the AIH workshop in 2017. Patients and patient representatives were actively involved in the parallel working groups alongside clinicians and researchers. Despite 40 years of experience with diagnosing and treating AIH, false diagnoses occur and treatment is still based on nonselective immunosuppression. In addition to the need for more specific diagnostic tests, prognostic markers and tailor-based treatments, a major unmet clinical need was identified in areas of care delivery and health-related quality of life.

[Autoimmune hepatitis : From autoantibodies to cirrhosis]

Autoimmune Hepatitis (AIH) is an immune-mediated liver disease of unknown origin. Its clinical presentation is heterogeneous and ranges from asymptomatic courses over several years to acute forms with acute liver failure. Accordingly, the diagnosis is only made at the stage of cirrhosis in about one third of affected individuals. Early diagnosis and a consistent, adequate, individualized, immunosuppressive therapy are crucial for the prognosis, which is excellent when treated properly. AIH is rare in the general population and can be easily overlooked due to its variable clinical picture and sometimes difficult diagnosis. AIH should be considered as a differential diagnosis in any unclear acute or chronic hepatopathy. The therapy initially consists of remission induction and subsequently maintenance therapy with (often lifelong) immunosuppressants.

Bioinformatics analyses of combined databases identify shared differentially expressed genes in cancer and autoimmune disease

BACKGROUND

Inadequate immunity caused by poor immune surveillance leads to tumorigenesis, while excessive immunity due to breakdown of immune tolerance causes autoimmune genesis. Although the function of immunity during the onset of these two processes appears to be distinct, the underlying mechanism is shared. To date, gene expression data for large bodies of clinical samples are available, but the resemblances of tumorigenesis and autoimmune genesis in terms of immune responses remains to be summed up.

METHODS

Considering the high disease prevalence, we chose invasive ductal carcinoma (IDC) and systemic lupus erythematosus (SLE) to study the potential commonalities of immune responses. We obtained gene expression data of IDC/SLE patients and normal controls from five IDC databases (GSE29044, GSE21422, GSE22840, GSE15852, and GSE9309) and five SLE databases (GSE154851, GSE99967, GSE61635, GSE50635, and GSE17755). We intended to identify genes differentially expressed in both IDC and SLE by using three bioinformatics tools including GEO2R, the limma R package, and Weighted Gene Co-expression Network Analysis (WGCNA) to perform function enrichment, protein-protein network, and signaling pathway analyses.

RESULTS

The mRNA levels of signal transducer and activator of transcription 1 (STAT1), 2'-5'-oligoadenylate synthetase 1 (OAS1), 2'-5'-oligoadenylate synthetase like (OASL), and PML nuclear body scaffold (PML) were found to be differentially expressed in both IDC and SLE by using three different bioinformatics tools of GEO2R, the limma R package and WGCNA. From the combined databases in this study, the mRNA levels of STAT1 and OAS1 were increased in IDC while reduced in SLE. And the mRNA levels of OASL and PML were elevated in both IDC and SLE. Based on Kyoto Encyclopedia of Genes and Genomes pathway analysis and QIAGEN Ingenuity Pathway Analysis, both IDC and SLE were correlated with the changes of multiple components involved in the Interferon (IFN)-Janus kinase (JAK)-signal transducer and activator of transcription (STAT) signaling pathway.

CONCLUSION

The expression levels of STAT1 and OAS1 manifest the opposite expression tendency across cancer and autoimmune disease. They are components in the IFN-JAK-STAT signaling pathway related to both tumorigenesis and autoimmune genesis. STAT1 and OAS1-associated IFN-JAK-STAT signaling could explain the commonalities during tumorigenesis and autoimmune genesis and render significant information for more precise treatment from the point of immune homeostasis.

Standard immunosuppressive treatment reduces regulatory B cells in children with autoimmune liver disease

Introduction

Autoimmune hepatitis (AIH) is a chronic liver disease caused by a perturbed immune system. The scarcity of short- and long-term immune monitoring of AIH hampered us to comprehend the interaction between immunosuppressive medication and immune homeostasis.

Methods and patients

We recruited children with AIH at the time of diagnosis and at the 1st, 3rd, 6th, 12th, 18th, and 24th months of immunosuppression (IS). We also enrolled children with AIH being on IS for >2 years. Children with drug-induced liver injury (DILI), and those receiving tacrolimus after liver transplantation (LT), were enrolled as disease/IS control subjects. Healthy children (HC) were also recruited. Peripheral blood mononuclear cells (PBMCs) were isolated from all participants. Healthy liver tissue from adult donors and from livers without inflammation were obtained from children with hepatoblastoma. By using flow cytometry, we performed multi-parametric immune profiling of PBMCs and intrahepatic lymphocytes. Additionally, after IS with prednisolone, tacrolimus, rapamycin, or 6-mercaptopurine, we carried out an in vitro cytokine stimulation assay. Finally, a Lifecodes SSO typing kit was used to type HLA-DRB1 and Luminex was used to analyze the results.

Results

Untreated AIH patients had lower total CD8 T-cell frequencies than HC, but these cells were more naïve. While the percentage of naïve regulatory T cells (Tregs) (CD4⁺FOXP3^lowCD45RA⁺) and regulatory B cells (Bregs, CD20⁺CD24⁺CD38⁺) was similar, AIH patients had fewer activated Tregs (CD4⁺FOXP3^highCD45RA ^- ) compared to HC. Mucosal-associated-invariant-T-cells (MAIT) were also lower in these patients. Following the initiation of IS, the immune profiles demonstrated fluctuations. Bregs frequency decreased substantially at 1 month and did not recover anymore. Additionally, the frequency of intrahepatic Bregs in treated AIH patients was lower, compared to control livers, DILI, and LT patients. Following in vitro IS drugs incubation, only the frequency of IL-10-producing total B-cells increased with tacrolimus and 6MP. Lastly, 70% of AIH patients possessed HLA-DR11, whereas HLA-DR03/DR07/DR13 was present in only some patients.

Conclusion

HLA-DR11 was prominent in our AIH cohort. Activated Tregs and MAIT cell frequencies were lower before IS. Importantly, we discovered a previously unrecognized and long-lasting Bregs scarcity in AIH patients after IS. Tacrolimus and 6MP increased IL-10+ B-cells in vitro.

The immunological characteristics of TSPAN1 expressing B cells in autoimmune hepatitis

Background and aims

Tetraspanin proteins are closely related to the functional changes of B cells, including antigen presentation, production of cytokines, and transduction. We aim to explore the potential role of Tetraspanin 1 (TSPAN1) in the biological activities of B cells in AIH.

Methods and results

Herein, this study found that numbers of cells expressing TSPAN1 were significantly increased in AIH patients compared to PBC, chronic hepatitis B, and healthy control (P < 0.0001). Moreover, there was a positive correlation between numbers of TSPAN1+ cells and AIH disease severity (P < 0.0001). Immunofluorescence staining further confirmed that TSPAN1 was primarily expressed on CD19+ B cells. Flow-cytometric analysis showed that TSPAN1+ B cells secreted more inflammatory cytokines and expressed higher level of CD86 than TSPAN1- B cells. Furthermore, compared with TSAPN1- cells, the expression of CXCR3 on TSPAN1+ cells was also higher. Meanwhile, CXCL10, the ligand of CXCR3, was significantly elevated in the liver of AIH (P < 0.01) and had positive correlation with the quantities of TSPAN1 (P < 0.05). Interestingly, the numbers of TSPAN1+ B cells were decreased in AIH patients after immunosuppressive therapy.

Conclusions

TSPAN1⁺ B cells in the liver may promote the progression of AIH via secreting cytokines and presenting antigens. The chemotactic movement of TSPAN1⁺ B cells toward the liver of AIH was possibly due to CXCR3 - CXCL10 interaction.

Role of B Lymphocytes in the Pathogenesis of NAFLD: A 2022 Update

Non-alcoholic fatty liver disease and its related complications are becoming one of the most important health problems globally. The liver functions as both a metabolic and an immune organ. The crosstalk between hepatocytes and intrahepatic immune cells plays a key role in coordinating a dual function of the liver in terms of the protection of the host from antigenic overload as a result of receiving nutrients and gut microbiota antigenic stimulation via facilitating immunologic tolerance. B cells are the most abundant lymphocytes in the liver. The crucial role of intrahepatic B cells in energy metabolism under different immune conditions is now emerging in the literature. The accumulating evidence has demonstrated that the antibodies and cytokines produced by B cells in the microenvironment play key and distinct roles in the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Herein, we have aimed to consolidate and update the current knowledge about the pathophysiological roles of B cells as well as the underlying mechanisms in energy metabolism. Understanding how B cells can exacerbate and suppress liver damage by exploiting the antibodies and cytokines they produce will be of great importance for designing B-cell targeting therapies to treat various liver diseases.