Quantification of polyreactive immunoglobulin G facilitates the diagnosis of autoimmune hepatitis.

BACKGROUND AND AIMS: Detection of autoantibodies is a mainstay of diagnosing autoimmune hepatitis (AIH). However, conventional autoantibodies for the workup of AIH lack either sensitivity or specificity, leading to substantial diagnostic uncertainty. We aimed to identify more accurate serological markers of AIH with a protein macroarray. APPROACH AND RESULTS: During the search for more-precise autoantibodies to distinguish AIH from non-AIH liver diseases (non-AIH-LD), IgG antibodies with binding capacities to many human and foreign proteins were identified with a protein macroarray and confirmed with solid-phase ELISAs in AIH patients. Subsequently, polyreactive IgG (pIgG) was exemplarily quantified by reactivity against human huntingtin-interacting protein 1-related protein in bovine serum albumin blocked ELISA (HIP1R/BSA). The diagnostic fidelity of HIP1R/BSA binding pIgG to diagnose AIH was assessed in a retrospective training, a retrospective multicenter validation, and a prospective validation cohort in cryoconserved samples from 1,568 adults from 10 centers from eight countries. Reactivity against HIP1R/BSA had a 25% and 14% higher specificity to diagnose AIH than conventional antinuclear and antismooth muscle antibodies, a significantly higher sensitivity than liver kidney microsomal antibodies and antisoluble liver antigen/liver pancreas antigen, and a 12%-20% higher accuracy than conventional autoantibodies. Importantly, HIP1R/BSA reactivity was present in up to 88% of patients with seronegative AIH and in up to 71% of AIH patients with normal IgG levels. Under therapy, pIgG returns to background levels of non-AIH-LD. CONCLUSIONS: pIgG could be used as a promising marker to improve the diagnostic workup of liver diseases with a higher specificity for AIH compared to conventional autoantibodies and a utility in autoantibody-negative AIH. Likewise, pIgG could be a major source of assay interference in untreated AIH.

T cell receptor repertoires within liver allografts are different to those in the peripheral blood.

BACKGROUND & AIMS: T cells are the main mediators of allogeneic immune responses. Specific T cell clones can be tracked by their unique T cell receptor (TCR), but specificity and function remain elusive and have not been investigated in human liver biopsies thus far. METHODS: TCR repertoire analysis of CD4+, CD8+, and regulatory T cells of the peripheral blood and liver graft was performed in 7 liver transplant recipients with either stable course (non-rejector, NR), subclinical cellular rejection (SCR), or acute cellular rejection (ACR) during an observation period from pre-transplant to 6 years post-transplant. Furthermore, donor-reactive T cells, identified by their expression of CD154 and glycoprotein A repetitions predominant (GARP) after allogeneic activation, were tracked longitudinally in peripheral blood and within the liver allograft. RESULTS: Although overall clonality of the TCR repertoire did not increase in peripheral blood after liver transplantation, clonality of donor-reactive CD4+ and regulatory T cells increased and these clones accumulated within the liver graft. Surprisingly, the TCR repertoires between the liver graft and the periphery were distinct and showed only limited overlap. Notably, during ACR, TCR repertoires aligned suggesting either graft-specific homing or release of activated T cells from the graft. CONCLUSIONS: This is the first study comparing TCR repertoires between liver grafts and blood in patients with NR, SCR, and ACR. Moreover, we attribute specificity and function to a subgroup of intragraft T cell populations. Given the limited overlap between peripheral blood and intragraft repertoires, future studies investigating function and specificities of T cells after liver transplantation should focus on the intragraft immune response. LAY SUMMARY: In solid organ transplantation, T cells are key mediators of the recipient's immune response directed at the transplanted organ. In our study, we characterised the T cell repertoire in a cohort of 7 liver transplant recipients. We demonstrate that donor-specific T cells expand clonally and accumulate in the transplanted liver. Moreover, we show that the composition of T cells in peripheral blood differs from the T cells in the liver allograft, only aligning in the context of acute cellular rejection but not in normal graft or subclinical cellular rejection. This indicates that the intragraft immune response is not mirrored in the peripheral blood. Our findings clarify the importance of protocol liver biopsies in identifying intragraft immune responses for future investigations of allo-directed immune responses.

Novel therapeutic targets in autoimmune hepatitis.

Autoimmune hepatitis (AIH) is an orphan disease characterized by an autoimmune attack against hepatocytes. The exact sequence of events that leads to a breach of tolerance is incompletely understood. Current hypotheses suggest that environmental agents such as toxins or infectious agents like viruses cause a tissue damage that initiates autoimmunity in genetically susceptible individuals. The growing knowledge of the multi-facetted immune dysregulation, which involves Th1/Th17 polarization and the suspected inability of regulatory T cells to revert autoimmunity in the otherwise tolerogenic milieu of the liver, offers multiple new therapeutic approaches and targets. Standard of care (SOC) is treatment with corticosteroids with or without azathioprine, which is sufficient to induce remission in the majority of patients. However, it rarely cures AIH or restores intrahepatic immune tolerance. Hence, life-long therapy is required in the majority of patients. In addition, several studies suggest a weakening of immune regulation mediated by intrahepatic T cells under current therapies. Furthermore, second line therapies for non-responders, intolerant or otherwise difficult to treat patients are urgently needed as this is relevant for at least one fifth of all patients with inefficacy or intolerance to SOC. Current second line therapies are mainly based on single center retrospective experiences and none of them have been approved by regulatory authorities for AIH, yet. This article highlights new therapeutic approaches based on our growing knowledge on the pathophysiology of AIH. It focuses on cell-based therapies that strengthen or restore immune tolerance. An additional focus lies on new therapeutic agents showing promising results in non-hepatic autoimmune diseases that have a potential for treating AIH. The dynamics in the whole field of innovative therapies for non-hepatic autoimmune diseases will hopefully improve the therapeutic armamentarium for AIH patients in the future.

Folic acid supplementation is associated with a decreased mortality and reduced hospital readmission in patients with decompensated alcohol-related liver cirrhosis.

BACKGROUND AND AIMS: Thiamine and folic acid malnutrition is highly frequent in patients with decompensated alcohol-related liver cirrhosis (aLC). Current guidelines therefore recommend vitamin supplementation in these patients. However, implementation and its impact on the clinical outcome remains unknown. Therefore, we aimed to analyze the use of thiamine and folic acid and their effects on mortality and morbidity in patients with decompensated aLC. METHODS: A number of 289 consecutive patients with decompensated aLC who received a paracentesis at Hannover Medical School between 2011 and 2023 were retrospectively investigated. The use of folic acid and thiamine-containing supplements was assessed in the discharge medication. Patients were followed for up to one year regarding liver transplant (LTx)-free survival and the incidence of hepatic encephalopathy, infections and hepatic decompensation requiring rehospitalization. RESULTS: Median baseline MELD was 15, median age 56.6 years. 73.0% (n = 211) were male patients. At hospital discharge, thiamine-containing supplements and folic acid were prescribed to 48.1% (n = 139) and 18.0% (n = 52) patients, respectively. Neither thiamine nor folic acid prescription were linked to improved clinical outcomes within 90 days. However, folic acid intake was associated with a higher one-year LTx-free survival (HR = 0.48; p = 0.04) in the multivariable analysis. Furthermore, folic acid substitution was linked to a decreased risk of rehospitalization within one year (HR = 0.55; p = 0.01) in the multivariable competing risk model. In contrast, thiamine prescription did neither affect LTx-free survival nor the here investigated liver-related complications. CONCLUSION: Folic acid, but not thiamine substitution was linked to an improved outcome in patients with decompensated aLC.

Detection of polyreactive immunoglobulin G facilitates diagnosis in children with autoimmune hepatitis.

OBJECTIVE: The detection of autoantibodies is essential to diagnose autoimmune hepatitis (AIH). Particularly in children, specificity of autoantibodies decreases due to lower titers being diagnostic and being present not only in AIH but also in other liver diseases. Recently, quantification of polyreactive IgG (pIgG) for detection of adult AIH showed the highest overall accuracy compared to antinuclear antibodies (ANA), anti-smooth muscle antibodies (anti-SMA), anti-liver kidney microsomal antibodies (anti-LKM) and anti-soluble liver antigen/liver pancreas antibodies (anti-SLA/LP). We aimed to evaluate the diagnostic value of pIgG for pediatric AIH. DESIGN: pIgG, quantified using HIP1R/BSA coated ELISA, and immunofluorescence on rodent tissue sections were performed centrally. The diagnostic fidelity to diagnose AIH was compared to conventional autoantibodies of AIH in training and validation cohorts from a retrospective, European multi-center cohort from nine centers from eight European countries composed of existing biorepositories from expert centers (n = 285). RESULTS: IgG from pediatric AIH patients exhibited increased polyreactivity to multiple protein and non-protein substrates compared to non-AIH liver diseases and healthy children. pIgG had an AUC of 0.900 to distinguish AIH from non-AIH liver diseases. pIgG had a 31-73% higher specificity than ANA and anti-SMA and comparable sensitivity that was 6-20 times higher than of anti-SLA/LP, anti-LC1 and anti-LKM. pIgG had a 21-34% higher accuracy than conventional autoantibodies, was positive in 43-75% of children with AIH and normal IgG and independent from treatment response. CONCLUSION: Detecting pIgG improves the diagnostic evaluation of pediatric AIH compared to conventional autoantibodies, primarily owing to higher accuracy and specificity.

Clinical long-term outcome of hepatitis D compared to hepatitis B monoinfection.

BACKGROUND AND AIMS: Hepatitis D virus (HDV) infection causes the most severe form of chronic viral hepatitis. However, it is still unclear to what extent the underlying cirrhosis may contribute to disease progression. The aim of this study was to compare the long-term outcome of HDV infection with HBV monoinfection in a single-center cohort of both non-cirrhotic and cirrhotic patients. METHOD: We retrospectively studied 175 patients with chronic hepatitis D (CHD) who were followed for at least 6 months (median of 6.3 (0.6-23.6) years). In addition, we selected 175 patients with HBV monoinfection (CHB) who were matched for gender, age, region of origin, HBeAg status, and bilirubin. Liver-related clinical end points were defined as hepatic decompensation (ascites, encephalopathy, variceal bleeding), liver transplantation, HCC, or liver-related death. RESULTS: Clinical complications developed earlier (4.6 vs. 6.2 years) and more frequently (35.4% vs. 12.6%, p < 0.01) in CHD patients. In a multivariate Cox regression, HDV infection was independently associated with the development of end points (p < 0.01; HR: 3.0; 95% CI 1.4-6.4). However, in cirrhotic patients there were no significant differences between HBV and HDV in the development of end points. Besides, CHB patients with cirrhosis developed more frequently HCC (35.5%) than CHD patients with cirrhosis (18.5%). CONCLUSION: Our results confirmed that HDV leads to a faster progression to cirrhosis compared to HBV. However, once cirrhosis is present, not HDV but the underlying cirrhosis is the dominate intrinsic risk factor for the development of liver-related end points and for the progression to HCC.

The Detrimental Role of Regulatory T Cells in Nonalcoholic Steatohepatitis.

Nonalcoholic steatohepatitis (NASH) is induced by steatosis and metabolic inflammation. While involvement of the innate immune response has been shown, the role of the adaptive immune response in NASH remains controversial. Likewise, the role of regulatory T cells (Treg) in NASH remains unclear although initial clinical trials aim to target these regulatory responses. High-fat high-carbohydrate (HF-HC) diet feeding of NASH-resistant BALB/c mice as well as the corresponding recombination activating 1 (Rag)-deficient strain was used to induce NASH and to study the role of the adaptive immune response. HF-HC diet feeding induced strong activation of intrahepatic T cells in BALB/c mice, suggesting an antigen-driven effect. In contrast, the effects of the absence of the adaptive immune response was notable. NASH in BALB/c Rag1-/- mice was substantially worsened and accompanied by a sharp increase of M1-like macrophage numbers. Furthermore, we found an increase in intrahepatic Treg numbers in NASH, but either adoptive Treg transfer or anti-cluster of differentiation (CD)3 therapy unexpectedly increased steatosis and the alanine aminotransferase level without otherwise affecting NASH. Conclusion: Although intrahepatic T cells were activated and marginally clonally expanded in NASH, these effects were counterbalanced by increased Treg numbers. The ablation of adaptive immunity in murine NASH led to marked aggravation of NASH, suggesting that Tregs are not regulators of metabolic inflammation but rather enhance it.

Dulaglutide Alone and in Combination with Empagliflozin Attenuate Inflammatory Pathways and Microbiome Dysbiosis in a Non-Diabetic Mouse Model of NASH.

Dysregulation of glucose homeostasis plays a major role in the pathogenesis of non-alcoholic steatohepatitis (NASH) as it activates proinflammatory and profibrotic processes. Beneficial effects of antiglycemic treatments such as GLP-1 agonist or SGLT-2 inhibitor on NASH in patients with diabetes have already been investigated. However, their effect on NASH in a non-diabetic setting remains unclear. With this aim, we investigated the effect of long-acting GLP1-agonist dulaglutide and SGLT-2 inhibitor empagliflozin and their combination in a non-diabetic mouse model of NASH. C57BL/6 mice received a high-fat-high-fructose (HFHC) diet with a surplus of cholesterol for 16 weeks. After 12 weeks of diet, mice were treated with either dulaglutide, empagliflozin or their combination. Dulaglutide alone and in combination with empagliflozin led to significant weight loss, improved glucose homeostasis and diminished anti-inflammatory and anti-fibrotic pathways. Combination of dulaglutide and empagliflozin further decreased MoMFLy6CHigh and CD4+Foxp3+ T cells. No beneficial effects for treatment with empagliflozin alone could be shown. While no effect of dulaglutide or its combination with empaglifozin on hepatic steatosis was evident, these data demonstrate distinct anti-inflammatory effects of dulaglutide and their combination with empagliflozin in a non-diabetic background, which could have important implications for further treatment of NASH.

Telemonitoring-Supported Exercise Training in Employees With Metabolic Syndrome Improves Liver Inflammation and Fibrosis.

INTRODUCTION: Metabolic syndrome (MetS) is a major health problem worldwide and the main risk factor for metabolic-associated fatty liver disease (MAFLD). Established treatment options are lifestyle interventions facilitating dietary change and increased physical activity. Here, we tested the effect of a telemonitoring-supported intervention on liver parameter of inflammation and fibrosis in individuals with MetS. METHODS: This was a prospective, randomized, parallel-group, and assessor-blind study performed in workers of the main Volkswagen factory (Wolfsburg, Germany). Volunteers with diagnosed MetS were randomly assigned (1:1) to a 6-month lifestyle intervention focusing on supervised, activity-tracker-guided exercise or to a waiting-list control group. This secondary analysis assessed the effect of the intervention on liver enzymes and MAFLD-related parameters. RESULTS: We screened 543 individuals between October 10, 2017, and February 27, 2018, of whom 314 were randomly assigned to the intervention group (n = 160) or control group (n = 154). Liver transaminases, alkaline phosphatase, and gamma-glutamyl transferase significantly decreased after 6 months in the intervention group compared with the CG. Furthermore, an aspartate aminotransferase-to-platelet ratio index score as a marker for liver fibrosis significantly decreased in the intervention group. These improvements were associated with changes in obesity and exercise capacity. DISCUSSION: A 6-month lifestyle intervention based on exercise training with individualized telemonitoring-based supervision led to improvements of liver inflammation and fibrosis in employees with MetS. Therefore, this intervention shows therapeutic potential for individuals at high risk of MAFLD (ClinicalTrials.gov Identifier: NCT03293264).