BACKGROUND & AIMS:Patients with autoimmune hepatitis (AIH) experience increased mortality and severe side effects from non-specific immunosuppressive therapy, highlighting an urgent need for targeted treatment approaches. Here, we aimed to delineate the cellular and molecular network underlying AIH within its spatial context and to validate a key therapeutic target in a clinical trial. METHODS:We employed computational modelling, multi-omics analyses, and functional experiments to map the immune landscape of AIH. In addition, we conducted a steroid-free open-label phase IIa clinical trial using infliximab, a TNF-targeting antibody, in patients with AIH. RESULTS:Our studies revealed that myeloid cell and hepatocyte-derived IL-15 promotes cytotoxicity and proliferation of liver auto-aggressive CD8+ T cells. Full execution of their cytotoxic program is licensed by TNF derived from clonally expanded liver-resident CD4+ T cells. AIH hepatocytes respond to TNF by increasing expression of adhesion molecules, making them targets for both CD8+ and CD4+ T cells. In the clinical trial, targeting TNF with infliximab demonstrated efficacy as an entirely steroid-free AIH treatment. CONCLUSIONS:These findings elucidate the immune network in AIH and identify TNF as one of the central network nodes. Accordingly, our findings provide the basis for novel targeted, steroid-free immune therapies, including the use of infliximab. CLINICAL TRIAL NUMBER:European Union Clinical Trials Register (EudraCT No.: 2017-003311-19). IMPACT AND IMPLICATIONS:These findings have significant implications for the treatment of autoimmune hepatitis (AIH). By mapping the spatial and functional immune network within the AIH liver, this study identifies IL-15 and TNF as central drivers of T cell-mediated cytotoxicity, offering new precision targets for intervention. The successful use of infliximab as a steroid-free therapy in a phase II trial marks a pivotal step toward safer, more specific treatment options for patients with AIH. This research not only advances our understanding of AIH pathogenesis, but also sets the stage for broader application of immune-targeted therapies in autoimmune liver diseases.

Background & Aims: Primary sclerosing cholangitis (PSC) is a chronic heterogenous cholangiopathy with unknown etiology where chronic inflammation of the bile ducts leads to multifocal biliary strictures and biliary fibrosis with consecutive cirrhosis development. We here aimed to identify a PSC-specific gene signature associated with biliary fibrosis development. Methods: We performed RNA-sequencing of 47 liver biopsies from people with PSC (n = 16), primary biliary cholangitis (PBC, n = 15), and metabolic dysfunction-associated steatotic liver disease (MASLD, n = 16) with different fibrosis stages to identify a PSCspecific gene signature associated with biliary fibrosis progression. For validation, we compared an external transcriptome data set of liver biopsies from people with PSC (n = 73) with different fibrosis stages (baseline samples from NCT01672853). Results: Differential gene expression analysis of the liver transcriptome from patients with PSC with advanced vs. early fibrosis revealed 431 genes associated with fibrosis development. Of those, 367 were identified as PSC-associated when compared with PBC or MASLD. Validation against an external data set of 73 liver biopsies from patients with PSC with different fibrosis stages led to a condensed set of 150 (out of 367) differentially expressed genes. Cell type specificity assignment of those genes by using published single-cell RNA-Seq data revealed genetic disease drivers expressed by cholangiocytes (e.g. CXCL1, SPP1), fibroblasts, innate, and adaptive immune cells while deconvolution along fibrosis progression of the PSC, PBC, and MASLD samples highlighted an early involvement of macrophage- and neutrophil-associated genes in PSC fibrosis. Conclusions: We reveal a PSC-attributed gene signature associated with biliary fibrosis development that may enable the identification of potential new biomarkers and therapeutic targets in PSC-related fibrogenesis. (c) 2024 The Author(s). Published by Elsevier B.V. on behalf of European Association for the Study of the Liver (EASL). This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) are autoimmune liver diseases with strong female predominance. They are caused by T cell-mediated injury of hepatic parenchymal cells, but the mechanisms underlying this sex bias are unknown. Here, we investigated whether testosterone contributes to T cell activation in women with PBC. Compared with sex- and age-matched healthy controls (n = 23), cisgender (cis) women with PBC (n = 24) demonstrated decreased testosterone serum levels and proinflammatory CD4+ T cell profile in peripheral blood. Testosterone suppressed the expression of TNF and IFN-γ by human CD4+ T cells in vitro. In trans men receiving gender-affirming hormone therapy (GAHT) (n = 25), testosterone affected CD4+ T cell function by inhibiting Th1 and Th17 differentiation and by supporting the differentiation into regulatory Treg. Mechanistically, we provide evidence for a direct effect of testosterone on T cells using mice with T cell-specific deletion of the cytosolic androgen receptor. Supporting a role for testosterone in autoimmune liver disease, we observed an improved disease course and profound changes in T cell states in a trans man with AIH/primary sclerosing cholangitis (PSC) variant syndrome receiving GAHT. We here report a direct effect of testosterone on CD4+ T cells that may contribute to future personalized treatment strategies.

Primary sclerosing cholangitis (PSC) is an immune-mediated liver disease of unknown pathogenesis, with a high risk to develop cirrhosis and malignancies. Functional dysregulation of T cells and association with genetic polymorphisms in T cell-related genes were previously reported for PSC. Here, we genotyped a representative PSC cohort for several disease-associated risk loci and identified rs56258221 (BACH2/MIR4464) to correlate with not only the peripheral blood T cell immunophenotype but also the functional capacities of naive CD4+ T (CD4+ TN) cells in people with PSC. Mechanistically, rs56258221 leads to an increased expression of miR4464, in turn causing attenuated translation of BACH2, a major gatekeeper of T cell quiescence. Thereby, the fate of CD4+ TN is skewed toward polarization into pro-inflammatory subsets. Clinically, people with PSC carrying rs56258221 show signs of accelerated disease progression. The data presented here highlight the importance of assigning functional outcomes to disease-associated genetic polymorphisms as potential drivers of diseases.

Die primär biliäre Cholangitis (PBC) ist eine chronische cholestatische Lebererkrankung, die unbehandelt zur Leberzirrhose fortschreiten kann. Die frühzeitige Diagnosestellung, Therapieeinleitung und gegebenenfalls Therapieanpassung ist daher essenziell, um eine Krankheitsprogression zu verhindern. Die Bewertung eines ausreichenden Therapieansprechens kann im klinischen Alltag eine Herausforderung darstellen, da Zeitpunkt und Grenzwerte zur Therapieevaluation in der Literatur uneinheitlich definiert sind. Neben der komprimierten Darstellung der leitliniengerechten Diagnostik und Erstlinientherapie soll diese Arbeit eine praktische Anleitung zur Therapieevaluation sowie Optionen der Zweitlinientherapie bei PBC darlegen. Der vorliegende Beitrag basiert auf der aktuellen Leitlinie der European Association for the Study of the Liver (EASL) zum Management der PBC von 2017 sowie auf einer Literaturrecherche der Studienlage (2017–2023) mit Fokus auf die Definition des Therapieansprechens, die Risikoabschätzung der Krankheitsprogression sowie die zugelassenen und in Testung befindlichen Substanzen der Zweitlinientherapie. Es existieren unterschiedliche Definitionen für das suffiziente Ansprechen auf die Therapie mit Ursodesoxycholsäure (UDCA). Die Therapieziele orientieren sich am individuellen Risiko einer Krankheitsprogression. Das geringste Risiko scheint bei einer Normalisierung der alkalischen Phosphatase (AP) sowie einem Serumbilirubinspiegel unterhalb des 0,6-fachen des oberen Grenzwerts vorzuliegen. Als erprobte Zweitlinientherapeutika stehen Obeticholsäure und Bezafibrat („off-label use“) zur Verfügung. Weitere Agonisten von Peroxisom-Proliferator-aktivierten Rezeptoren (PPAR) und Kombinationstherapien befinden sich in klinischer Testung. Nach Therapieeinleitung sollte eine frühzeitige Evaluation des Therapieerfolgs stattfinden und bei unzureichendem Therapieansprechen gemäß dem individuellen Risikoprofil eine Zweitlinientherapie eingeleitet werden.

BACKGROUND:Primary biliary cholangitis (PBC) is a chronic cholestatic liver disease that can progress to liver cirrhosis if left untreated. Early diagnosis, initiation of therapy and, if necessary, adjustment of treatment are essential to prevent disease progression. The timing and thresholds for assessing adequate treatment response are inconsistently defined in the literature and can pose a challenge in clinical practice. OBJECTIVE:In addition to providing a concise overview of the guideline-based diagnostic work-up and first-line therapy, this study offers practical guidance for the evaluation of treatment response and options for second-line treatment in PBC. MATERIALS AND METHODS:This article is based on the current European Association for the Study of the Liver (EASL) clinical practice guidelines for the management of PBC from 2017 as well as a literature review of studies from 2017 to 2023, focusing on defining treatment response, assessing disease progression risk, and the approved and investigational agents for second-line therapy. RESULTS:There are varying definitions for a sufficient response to ursodeoxycholic acid (UDCA). Therapeutic goals are tailored to the individual risk of disease progression. The lowest risk appears to be associated with normalization of alkaline phosphatase (AP) and serum bilirubin below 0.6 the upper limit of normal. Established second-line therapies include obeticholic acid and bezafibrate (off-label use), while other peroxisome proliferator-activated receptor (PPAR) agonists and combination therapies are under clinical investigation. DISCUSSION:Early evaluation of treatment response to UDCA is mandatory. In the case of insufficient treatment response, second-line therapy should be initiated according to the individual's risk profile.

BACKGROUND AND AIMS:There is little data on the hepatic efficacy and safety of immunomodulatory drugs used in patients with autoimmune hepatitis (AIH), despite their established use in dermatology, rheumatology and inflammatory bowel diseases (IBD). Our aim was to collect real-life data on the experience of expert centres in treating AIH patients with these drugs, considered unconventional for AIH management. METHODS:Online survey among hepatology centres being part of the European Reference Network on Hepatological Diseases (ERN RARE-LIVER). RESULTS:25 AIH patients have been reported. Ten were female, median age at diagnosis was 28 years; median follow-up was 17 months. All had initially received AIH-standard treatment. AIH-unconventional treatment was initiated for concomitant autoimmune diseases in 15 cases: nine for IBD (five vedolizumab and four ustekinumab), and one each for following diseases: autoinflammatory syndrome (tocilizumab), chronic urticaria (omalizumab), rheumatoid arthritis (abatacept), psoriasis (guselkumab), psoriatric arthritis (secukinumab, followed by ustekinumab) and alopecia (ruxolitinib). Three patients were treated with immunomodulatory drugs for side effects of previous treatments, including two patients with IBD treated with vedolizumab and ustekinumab, respectively, and one treated with belimumab. At the end of follow-up, 13 patients were in complete biochemical response, the patient on omalizumab had a relapse, and four patients with concomitant IBD had insufficient response. Seven patients were treated for lack of biochemical remission, of whom six with belimumab, all initially reaching complete biochemical response, but five relapsing during follow-up; and one with secukinumab, having concomitant rheumatoid arthritis and ankylosing spondylitis, reaching complete biochemical response. Only the patient on abatacept received unconventional treatment as monotherapy. Side effects were reported in two patients on belimumab: one recurrent soft tissue infections, one fatigue and arthralgia. CONCLUSION:Among 25 AIH patients who were treated with immunomodulatory drugs for different reasons, the majority had a fovorable course, relapse was frequent in difficult-to-treat patients who received belimumab, and four with concomitant IBD had insufficient response.

Background: Variant syndromes of autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) share diagnostic features of both entities, but their immunological underpinnings remain largely unexplored. Methods: We performed blood profiling of 23 soluble immune markers and immunogenetics in a cohort of 88 patients with autoimmune liver diseases (29 typical AIH, 31 typical PBC and 28 with clinically PBC/AIH variant syndromes). The association with demographical, serological and clinical features was analyzed. Results: While T and B cell receptor repertoires were highly skewed in variant syndromes compared to healthy controls, these biases were not sufficiently discriminated within the spectrum of autoimmune liver diseases. High circulating checkpoint molecules sCD25, sLAG-3, sCD86 and sTim-3 discriminated AIH from PBC on top of classical parameters such as transaminases and immunoglobulin levels. In addition, a second cluster of correlated soluble immune factors encompassing essentially TNF, IFNγ, IL12p70, sCTLA-4, sPD-1 and sPD-L1 appeared characteristic of AIH. Cases with complete biochemical responses to treatment generally showed a lower level of dysregulation. Unsupervised hierarchical clustering of classical and variant syndromes identified two pathological immunotypes consisting predominantly of either AIH or PBC cases. Variant syndromes did not form a separate group, but clustered together with either classical AIH or PBC. Clinically, patient with AIH-like variant syndromes were less likely to be able discontinue immunosuppressive treatment. Conclusions: Our analyses suggest that variants of immune mediated liver diseases may represent an immunological spectrum from PBC to AIH-like disease reflected by their pattern of soluble immune checkpoint molecules rather than separate entities.