Liver transplantation immunology: Immunosuppression, rejection, and immunomodulation

Neutrophil extracellular traps activate STING signaling to promote dendritic cell-driven rejection after liver transplantation

PURPOSE

Post-transplant immune rejection affects graft function. Interaction between neutrophil extracellular traps (NETs) with specific immune cells and the specific mechanism in liver transplantation were still unclear.

METHOD

Clinical patients RNA-Seq results were used for GSEA and KEGG analysis. C57BL/6 and C3H mouse models and clinical samples were use to describe the disease phenotype characteristics through multiple immunofluorescence, flow cytometry and etc. Cell co-culture experiments were performed to clarify the mechanism pathway process.

RESULTS

RNA-Seq results analysis indicated that the NETs formation pathway was upregulated. Animal models confirmed that in liver transplant immune rejection status the formation of NETs in situ and peripheral cells increased and the level of cell-free DNA (cf-DNA) in peripheral cells increased. Reactive oxygen species (ROS) as a predisposing factor for NETs accumulated more in immune rejection status and NETs are rich in mitochondrial DNA (mtDNA). NETs promote dendritic cell maturation through STING-related pathways. NETs formation increases in patients with liver transplant immune rejection and is positively correlated with disease severity.

CONCLUSION

We found that NETs can regulate dendritic cell maturation through STING-related pathways after liver transplantation, which may ultimately promote the occurrence of liver transplant rejection, providing a new perspective for clinical diagnosis, treatment and prevention of liver transplant rejection.

Macrophage-Tased Dual-Phase T Cell Immunomodulation to Combat Transplant Rejection

Transplant rejection remains a major challenge, driven primarily by the activation of alloreactive T cells. While enhancement of PD-L1 checkpoint molecules has exhibited potential in inhibiting T cell activity, its efficacy is often hindered by limited specificity and inadequate efficiency. Herein, a novel dual-phase immune modulation strategy is developed in which CTLA4-Ig and PD-L1 provide distinct, non-redundant inhibitory signals during the initial activation phase and the post-activation phase of T cells. PD-L1 is stably expressed on macrophages (sPD-L1 M) through lentiviral transduction, allowing them to leverage their chemotactic and antigen-presenting functions to target and deliver PD-L1 to transplant rejection sites. Notably, sPD-L1 M exhibited adaptive targeting capabilities, increasing their migration to grafts in response to heightened rejection. In an allograft skin model, the combined intravenous administration of sPD-L1 M and subcutaneous administration of CTLA4-Ig demonstrated synergistic efficacy, significantly suppressing alloreactive T cell activation, enhancing the recruitment of regulatory T cells (Tregs), downregulating pro-inflammatory cytokines, and prolonging allograft survival compared to either treatment alone. This study presents a promising strategy to effectively suppress T cell activity and prevent allogeneic immune responses without systemic immunosuppression.

Bortezomib as a Potential Treatment for Recurrent Autoimmune Hepatitis Following Pediatric Liver Transplantation

BACKGROUND

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease that can progress to liver cirrhosis and end-stage liver disease, often necessitating liver transplantation (LT). Pediatric LT has significantly improved survival outcomes, but complications such as acute steroid-resistant rejection and AIH recurrence pose serious challenges.

CASE PRESENTATION

We report the first documented pediatric liver transplantation case in Uzbekistan, performed on a 14-year-old boy with liver cirrhosis secondary to AIH. Despite successful surgery, the patient developed acute steroid-resistant graft rejection and was unresponsive to pulse methylprednisolone therapy and anti-thymocyte globulin (ATG), which also induced adverse effects, including polyneuropathy and hypertension. Further evaluation revealed reactivation of AIH, confirmed by elevated ANA and ANCA titers. Conventional therapies failed to control the disease, prompting the use of bortezomib, a proteasome inhibitor. After the initial dose of bortezomib, significant improvement in bilirubin levels and liver synthetic function was observed. A second dose, administered 7 days later, resulted in the normalization of liver function markers and serological antibodies by postoperative Day 30. The patient was discharged in stable condition under a triple immunosuppressive regimen. To the best of our knowledge, we report the first documented case of using bortezomib for the treatment of recurrent autoimmune hepatitis in a pediatric patient following liver transplantation.

CONCLUSION

This case emphasizes the effective use of bortezomib as a rescue therapy for steroid-resistant rejection and the recurrence of autoimmune hepatitis following pediatric liver transplantation. It highlights the significance of alternative therapeutic approaches in addressing complex post-transplant immune complications. Furthermore, this case prompts crucial considerations for future research, such as the monitoring of autoimmune disease reactivation and the potential role of drugs like bortezomib in managing immune-related complications after liver transplantation.

Chimerism and immunological tolerance in solid organ transplantation

In solid organ transplantation, chimerism inevitably occurs via the coexistence of donor-derived cells from the graft and host cells throughout the recipient. However, long-term immunosuppressive treatment is needed to suppress host immune responses to the foreign organ graft. The deliberate induction of stable mixed bone marrow chimerism to achieve donor-specific immunological tolerance in solid organ graft recipients is an ambitious goal that may significantly contribute to the long-term survival of solid organ grafts and their recipients. While this strategy has been effectively established in laboratory animals and some promising clinical case series have been reported, widespread clinical application is still limited by the toxicity of the necessary conditioning regimens. On the other hand, the naturally occurring chimeric state resulting from the bidirectional transplacental cell trafficking during pregnancy, the so-called feto-maternal microchimerism, can also induce immune tolerance and thus influence the outcome of mother-to-child or child-to-mother organ transplantation. This review provides an overview of the field's historical development, clinical results, and underlying principles of (micro) chimerism-based tolerance.

Regulation of the immune microenvironment and immunotherapy after liver transplantation

Liver transplantation (LT) is a primary treatment option for patients with end-stage liver disease. However, post-transplantation immune regulation is critical to graft survival and long-term patient outcomes. Following liver transplantation, the recipient's immune system mounts a response against the graft, while the graft promotes anti-rejection immune reactions and the establishment of immune tolerance. In recent years, advances in the study of the immune microenvironment have provided new insights into post-transplantation immune regulation. Meanwhile, immunotherapy strategies have opened new possibilities for improving transplantation success rates and long-term survival. This review summarizes recent progress in understanding the immune microenvironment and immunotherapy following liver transplantation, focusing on key components of the transplant immune microenvironment, their regulatory networks and mechanisms, major immunosuppressive strategies, emerging immunotherapeutic approaches, and current challenges. The aim was to provide a theoretical foundation for optimizing clinical practice.

Decoding the Resistin-CAP1 Pathway in Intermediate Monocytes Mediating Liver Allograft Rejection

BACKGROUND & AIMS

Lymphocytes are widely recognized as the primary mediators of cellular rejection post-liver transplantation. However, conventional immunosuppressive regimens that target lymphocytes, such as calcineurin phosphatase inhibitors, corticosteroids, or lymphocyte-depleting antibodies, can only partially mitigate rejection while inducing severe adverse effects. This necessitates the search for novel immunotherapeutic targets.

METHODS

We harnessed the power of single-cell RNA sequencing and spatial transcriptome in 24 rat transplanted liver and peripheral blood single nucleated cells (PBMCs) samples to derive gene expression signatures recapitulating 13 cell phenotypes. We used flow cytometry, multifactor assays and multiple recombinant assays to validate in vitro and in vivo the role of the target protein Resistin on human T-cell function, as well as the Resistin-CAP1 interaction. Gold nanoparticles were used to package Retn siRNA sequences to validate the role of Retn knockdown on acute rejection after liver transplantation.

RESULTS

By distinguishing between donor and recipient cells, we delineate the dynamic landscape of immune cells during allograft rejection and their spatial distributions across donors and recipients. Our findings underscore the pivotal role of recipient derived intermediate monocytes in cellular rejection. Using CellChat ligand-receptor analysis, we identify the Resistin-CAP1 pathway as a key mechanism by which intermediate monocytes participate in T cell-mediated rejection reactions. We confirm that Resistin knockdown significantly alleviates acute rejection after rat liver transplantation, markedly extending the survival of recipients using innovative nanogold technology.

CONCLUSION

These findings offer insights into the dynamic changes in the alloimmune microenvironment, pinpointing intermediate monocytes as potential diagnostic and immunotherapeutic targets during allograft rejection. This study holds significant importance in advancing non-invasive diagnostic technologies and immunotherapeutic strategies for allogeneic rejection.

IMPACT AND IMPLICATIONS

This study pioneers the application of spatial transcriptomics in liver transplantation, providing a comprehensive analysis of immune cell spatial distribution, complemented by Souporcell-based chimerism assessment. We demonstrate that intermediate monocytes play a pivotal role in T cell-mediated acute rejection via the Resistin-CAP1 signaling axis. Targeting this pathway using nanogold-siRNA technology effectively mitigates rejection and enhances graft survival. These findings contribute novel insights into the mechanisms of transplant rejection and present promising avenues for the development of targeted therapeutic and diagnostic strategies in liver transplantation.

Liver transplantation for hepatocellular carcinoma following immunotherapy

PURPOSE OF REVIEW

To explore the emerging use of immune checkpoint inhibitors (ICIs) in hepatocellular carcinoma (HCC) patients eligible for liver transplantation (LT), particularly as bridging and downstaging therapies. This review also addresses the clinical challenges of integrating ICIs into transplant protocols, including graft rejection, immune-related toxicities, and gaps in evidence.

RECENT FINDINGS

ICIs have shown potential as bridging and downstaging therapies before LT, with multicentric studies reporting 75.6% successful downstaging, 85% 3-year post-LT survival, and 7.2% rejection-related mortality. A washout interval >94 days and older age have been identified as protective factors against allograft rejection. Combining locoregional therapies with ICIs has proven effective in the EMERALD-1 and LEAP-012 trials, which demonstrated improved progression-free survival (15.0 and 14.6 months, respectively) with ICI-TACE combinations. Similarly, the STAR-FIT phase II trial, combining TACE, SBRT, and avelumab, showed a 42% complete response rate and 12% conversion to curative therapy. Toxicity and rejection risk remain major challenges.

SUMMARY

ICIs represent a promising tool for expanding transplant eligibility in HCC, but their integration into LT pathways remains complex. Safety concerns, particularly regarding timing and immune modulation, require careful evaluation. Prospective studies and biomarker development are needed to guide clinical decision-making. Novel therapies such as CAR-T cells may offer more targeted approaches in the future.

Advances in Subclinical and Clinical Trials and Immunosuppressive Therapies in Xenotransplantation

Organ transplantation remains the foremost effective intervention for end-stage organ failure. Nevertheless, the scarcity of donors has resulted in prolonged waiting times for countless patients globally. The advent of xenografts presents a promising solution to the organ shortage crisis. Although the utilization of xenografts has a long history, it is only in recent years that breakthroughs in genetically modified pigs have rendered successful xenotransplantation a feasible option. In the past 4 years, numerous subclinical and clinical trials have involved xenotransplantation from genetically modified pigs to humans. However, the outcomes have been disappointing, necessitating a reassessment of basic and preclinical research to address the emerging challenges. Furthermore, immunosuppressive therapies remain essential in xenotransplantation. The range of immunosuppressive agents, encompassing traditional immunosuppressants and monoclonal antibodies such as anti-CD154/CD40 monoclonal antibodies, exhibits considerable diversity. However, the most effective drug combination for achieving optimal efficacy remains elusive. This review will offer a succinct overview of the results from recent clinical and subclinical xenotransplantation trials. Moreover, it will highlight recent advancements in immunosuppressive strategies and discuss potential future research directions in this field.

Immunosuppression Post-Liver Transplant: End of the Calcineurin Era?

The introduction of calcineurin inhibitors (CNIs) as the primary form of immunosuppression (IS) for liver transplantation (LT) in the late 1970s was a key in increasingly successful outcomes for transplantation over the past 3 decades. Despite the side effects of CNI which directly contribute to the long-term morbidity and mortality post-LT, they will remain the cornerstone of IS in the near future. Efforts to minimize exposure to CNI will require the application of blood and tissue biomarkers that accurately identify the extent of IS and risk of rejection for individual patients.

Recurrence of autoimmune hepatitis cholestatic variant syndromes after liver transplantation affects graft and patient survival

Background & Aims

A significant proportion of patients with variant syndromes (VSs), namely autoimmune hepatitis/primary biliary cholangitis or autoimmune hepatitis/primary sclerosing cholangitis, require liver transplantation (LT) despite treatment. The frequency of disease recurrence and the effect on graft survival are yet to be clarified. The aim of this international, multicentric, retrospective study is to evaluate the risk factors associated with recurrence and the impact of the disease recurrence after LT on graft and patient survival.

Methods

We evaluated 166 patients undergoing LT for VS in 33 centers in North America, South America, Europe, and Asia. Clinical data before and after LT, biochemical data within the first 12 months after LT, and immunosuppression after LT were analyzed to identify patients with a higher risk of recurrence of autoimmune disease based on a histological and radiological diagnosis. Cumulative probabilities of graft and overall survival after LT were calculated using a semi-Markov model.

Results

The autoimmune pattern of recurrence resembled the original VS in 19 cases (61%). Recurrence of autoimmune liver disease (rALD) after LT was observed in 23% and 33% of patients after 5 and 10 years, respectively. Increased alkaline phosphatase (hazard ratio [HR] 1.60, 95% confidence interval [CI] 1.13-2.25, p <0.01) and alanine aminotransferase (HR 1.25, 95% CI 1.01-1.53, p = 0.03) at 12 months after LT and acute rejection (HR 3.58, 95% CI 1.60-7.73, p <0.01) were associated with a higher risk of VS recurrence, whereas the use of predniso(lo)ne was associated with a reduced risk (HR 0.30, 95% CI 0.14-0.64, p <0.01). After adjusting for alanine aminotransferase and alkaline phosphatase at 12 months, the use of predniso(lo)ne was found to be independently and negatively associated with recurrent disease. The rALD was found to be significantly associated with graft loss and patient survival in the multivariate Cox regression analysis with a time-dependent covariate. The 5- and 10-year probabilities of graft survival were 68% and 41% in patients with recurrent VS compared with 83% and 60% in patients without recurrent disease, respectively (p = 0.01). The overall survival was significantly reduced in patients with recurrent disease (p = 0.01), with event probability at 5 and 10 years of 75% and 49% vs. 84% and 60% in patients without recurrence, respectively.

Conclusions

rALD after LT is frequent and is associated with elevation in liver enzymes within the first year after LT and rejection episodes. According to our data, VS recurrence appears to be associated with poorer graft and patient survival. Further studies are needed to explore strategies that can prevent VS recurrence or mitigate its potential impact.

Impact and implications

This study investigated the recurrence of autoimmune liver diseases (rALD) in patients transplanted for variant syndromes (VSs) and its effect on graft and patient survival. The findings reveal a significant association between rALD and poorer graft and overall survival, highlighting the need for preventive strategies. This research is crucial for transplant physicians and healthcare providers, as it underscores the impact of early liver enzyme monitoring and tailored immunosuppressive therapy on long-term outcomes. These insights can inform more effective post-LT management protocols, potentially improving patient prognosis.

The effects of interleukin-21 in the biology of transplant rejection

Interleukin-21 (IL-21) is a cytokine that plays a crucial role in regulating immune responses, affecting various immune cell types, including T cells, B cells, natural killer (NK) cells, and dendritic cells. IL-21 is primarily produced by CD4+ T cells, particularly follicular helper T (Tfh) cells and Th17 cells, and has been shown to be extensively involved in regulating both innate and adaptive immunity. IL-21 is particularly significant in the differentiation, proliferation, and effector functions of T cells and B cells. In the context of organ transplantation, IL-21 contributes to the promotion of acute transplant rejection and the development of chronic rejection, which is primarily antibody-mediated. This review summarizes relevant studies on IL-21 and discusses its multifaceted roles in transplant immune rejection, providing insights into therapeutic strategies for either inhibiting graft rejection or promoting tolerance. It also explores the feasibility of blocking the IL-21 signaling pathway within current immunosuppressive regimens, aiming to provide further clinical references.

Successful Liver Transplantation After Achieving Complete Clinical Remission of Hepatocellular Carcinoma With Combination Therapy of Immune Checkpoint Inhibitors and Targeted Agents: A Case Report

Immunotherapy, primarily with immune checkpoint inhibitors, has become pivotal in the treatment of advanced hepatocellular carcinoma (HCC), leading to significant tumor burden reduction. However, its applicability in liver transplantation remains controversial. Due to the potential risks of rejection limiting large-scale clinical trials and the incomplete understanding of underlying mechanisms, whether transplant recipients can benefit from immunotherapy remains uncertain. This report describes the application of immunotherapy in liver transplantation, wherein two patients achieved complete tumor remission after receiving immunotherapy combined with other treatments before transplantation, enabling successful liver transplantation surgeries. Additionally, one patient received combination therapy with tislelizumab and lenvatinib before transplantation (Case 2), representing the first reported case utilizing this combination therapy as a bridging treatment before LT.

Targeting Metabolism: Innovative Therapies for MASLD Unveiled

The recent introduction of the term metabolic-dysfunction-associated steatotic liver disease (MASLD) has highlighted the critical role of metabolism in the disease's pathophysiology. This innovative nomenclature signifies a shift from the previous designation of non-alcoholic fatty liver disease (NAFLD), emphasizing the condition's progressive nature. Simultaneously, MASLD has become one of the most prevalent liver diseases worldwide, highlighting the urgent need for research to elucidate its etiology and develop effective treatment strategies. This review examines and delineates the revised definition of MASLD, exploring its epidemiology and the pathological changes occurring at various stages of the disease. Additionally, it identifies metabolically relevant targets within MASLD and provides a summary of the latest metabolically targeted drugs under development, including those in clinical and some preclinical stages. The review finishes with a look ahead to the future of targeted therapy for MASLD, with the goal of summarizing and providing fresh ideas and insights.

New Scenarios in Liver Transplantation for Hepatocellular Carcinoma

BACKGROUND AND AIMS

Despite liver transplantation (LT) is considered the optimal treatment for hepatocellular carcinoma (HCC), particularly in patients with impaired liver function, the shortage of donors has forced the application of very restrictive criteria for selecting ideal candidates for whom LT can offer the best outcome. With the evolving LT landscape due to the advent of direct-acting antivirals (DAAs) and the steady increase in donors, major efforts have been made to expand the transplant eligibility criteria for HCC. In addition, the emergence of immune checkpoint inhibitors (ICIs) for the treatment of HCC, with demonstrated efficacy in earlier stages, has revolutionized the therapeutic approach for these patients, and their integration in the setting of LT is challenging. Management of immunological compromise from ICIs, including the wash-out period before LT and post-LT immunosuppression adjustments, is crucial to balance the risk of graft rejection against HCC recurrence. Additionally, the effects of increased immunosuppression on non-hepatic complications must be understood to prevent them from becoming obstacles to long-term OS.

METHODS AND RESULTS

In this review, we will evaluate the emerging evidence and its implications for the future of LT in HCC. Addressing these novel challenges and opportunities, while integrating the current clinical evidence with predictive algorithms, would ensure a fair balance between individual patient needs and the overall population benefit in the LT system.

Postoperative circulating tumor cells predict the benefits of tyrosine kinase inhibitor for hepatocellular carcinoma after transplantation

AIM

Circulating tumor cells (CTC) have shown promise in predicting the outcomes of adjuvant treatments for several malignancies. The clinical significance of CTC in predicting the efficacy of tyrosine kinase inhibitor (TKI) administration in patients with hepatocellular carcinoma (HCC) was unclear.

METHODS

A total of 429 patients who underwent liver transplantation for HCC had provided 335 preoperative and 373 postoperative blood samples that could be used for CTC detection (pre-CTC and post-CTC). The association of the pre-CTC and post-CTC findings with the efficacy of TKI administration was assessed. Additionally, CTC surveillance was performed in 27 patients during TKI administration.

RESULTS

Patients with detectable post-CTC, instead of pre-CTC, showed a significantly longer time to recurrence when receiving a TKI after liver transplantation for HCC (hazard ratio 0.57; P = 0.042). Whereas patients without detectable post-CTC did not benefit from the TKI administration (P = 0.270). Furthermore, we also found that patients who persistently harbored CTC during TKI administration showed significantly higher early recurrence rates (≤1 year; 40% vs. 5.9%, P < 0.001) and a shorter time to recurrence (HR 7.03; P < 0.001) than those whose CTC status switched from positive to negative. In addition, longitudinal CTC monitoring demonstrated that CTC tended to reflect drug resistance during TKI administration.

CONCLUSIONS

The postoperative CTC level could predict the efficacy of TKI treatment for HCC patients after liver transplantation. Dynamic monitoring for CTC during treatment could sensitively reflect the response to the TKI, the development of drug resistance, and foresee tumor recurrence.

Safety of acamprosate for alcohol use disorder after liver transplant: A pilot randomized controlled trial

Acamprosate is a therapy for alcohol use disorder, but data on feasibility and safety in recipients of liver transplants are lacking. This was a single-center unblinded prospective pilot randomized controlled trial of adults (≥18 y) with liver transplant for alcohol-associated liver disease enrolled between 2021 and 2023, who were randomized 2:1 to the intervention of acamprosate (666 mg dose 3 times daily) or standard of care (SOC) over 14 weeks. Outcomes included safety (prevalence of adverse events [AEs]), feasibility (weekly survey response rate >60%), adherence (self-reported acamprosate use >60%), and efficacy (reduction in Penn Alcohol Craving Scale), and relapse-blood phosphatidylethanol (≥20 ng/mL/reported alcohol use) evaluated by standardized weekly surveys. The efficacy analysis was done in both the intention-to-treat (excluding withdrawals before medication administration) and per-protocol population (excluding withdrawals/<4 weeks participation). Of 78 participants who were approached, 30 enrolled (19 acamprosate and 11 SOC) with similar baseline characteristics. Eight participants withdrew (6 acamprosate before medication administration and 2 SOC). AEs were similar between acamprosate and SOC groups (92.3% vs. 90.0%, p > 0.99), including grade 3 AEs (53.9% vs. 60.0%, p > 0.99) with no reported grade 4/5 AEs. Survey response rates were similar in acamprosate versus SOC groups (61.0% vs. 76.0%, p = 0.19), and 69.0% were acamprosate adherents. Baseline Penn Alcohol Craving Scale values were low with no difference by the group in median absolute change in Penn Alcohol Craving Scale for intention-to-treat (0, IQR: -4 to 0 vs. 0, IQR: 0-0, p = 0.32), and per-protocol analyses (-1, IQR: -6 to 0 vs. 0, IQR: -0 to 0, p = 0.36). There was no reported or biochemical evidence of alcohol relapse. In this pilot study, preliminary data suggest that acamprosate may be safe and feasible. These data can inform larger studies and clinician efforts to address alcohol use disorder in post-liver transplant care (ClinicalTrials.gov, Number: NCT06471686).

Application progress of early nutrition intervention in patients with hepatocellular carcinoma after liver transplantation

Liver transplantation, as an effective therapy for patients with liver cancer, plays an important role in improving the quality of life of patients. However, the complexity and trauma of liver transplantation can easily lead to the occurrence of malnutrition in patients, and then increase the risk of postoperative complications, which has aroused widespread clinical attention. Reasonable nutritional support can not only maintain the stability of the body's internal environment, reduce the occurrence of complications, but also promote the recovery of liver and other organ functions. In recent years, with the in-depth understanding of nutritional metabolism after liver transplantation, the application of enteral nutrition and parenteral nutrition in nutritional support after liver transplantation has been increasingly extensive and achieved remarkable results. This paper discusses the effect of early postoperative nutritional intervention on patients with liver cancer and liver transplantation, and combined with its mechanism of action, can better understand the effectiveness of intervention, and provide reference for the development of scientific and reasonable nutritional support programs in clinical practice.

Lesson learnt from 60 years of liver transplantation: Advancements, challenges, and future directions

Over the past six decades, liver transplantation (LT) has evolved from an experimental procedure into a standardized and life-saving intervention, reshaping the landscape of organ transplantation. Driven by pioneering breakthroughs, technological advancements, and a deepened understanding of immunology, LT has seen remarkable progress. Some of the most notable breakthroughs in the field include advances in immunosuppression, a revised model for end-stage liver disease, and artificial intelligence (AI)-integrated imaging modalities serving diagnostic and therapeutic roles in LT, paired with ever-evolving technological advances. Additionally, the refinement of transplantation procedures, resulting in the introduction of alternative transplantation methods, such as living donor LT, split LT, and the use of marginal grafts, has addressed the challenge of organ shortage. Moreover, precision medicine, guiding personalized immunosuppressive strategies, has significantly improved patient and graft survival rates while addressing emergent issues, such as short-term complications and early allograft dysfunction, leading to a more refined strategy and enhanced post-operative recovery. Looking ahead, ongoing research explores regenerative medicine, diagnostic tools, and AI to optimize organ allocation and post-transplantation car. In summary, the past six decades have marked a transformative journey in LT with a commitment to advancing science, medicine, and patient-centered care, offering hope and extending life to individuals worldwide.

LXRα agonists ameliorates acute rejection after liver transplantation via ABCA1/MAPK and PI3K/AKT/mTOR signaling axis in macrophages

INTRODUCTION

Liver X receptor α (LXRα) plays an important role in inflammatory immune response induced by hepatic ischemia-reperfusion injury (IRI) and acute rejection (AR). Macrophage M1-polarization play an important role in the occurrence and development of AR. Although the activation of LXR has anti-inflammatory effects, the role of LXRα in AR after liver transplantation (LT) has not been elucidated.

OBJECTIVE

We aimed to investigate LXRα anti-inflammatory and macrophage polarization regulation effects and mechanisms in acute rejection rat models.

METHODS

LXRα anti-inflammatory and liver function protective effects was initially measured in primary Kupffer cells and LT rat models. Subsequently, a flow cytometry assay was used to detect the regulation effect of LXRα in macrophage polarization. HE staining, TUNEL and ELISA were used to evaluate the co-treatment effects of TO901317 and tacrolimus on hepatic apoptosis and liver acute rejection after LT.

RESULTS

In this study, we found that LPS can inhibit the expression of LXRα and activate MAPK pathway and PI3K/AKT/mTOR. We also found that LXRα agonist (TO901317) could improve liver function and rat survival after LT by activating the level of ABCA1 and inhibiting MAPK. TO901317 could inhibit macrophage M1-polarization by activating PI3K/AKT/mTOR signal pathway to improve the liver lesion of AR rats after liver transplantation. Additionally, co-treatment with TO901317 and tacrolimus more effectively alleviated the damaging effects of AR following LT than either drug alone.

CONCLUSION

Our results suggest that the activation of LXRα can improve liver function and rat survival after LT by regulate ABCA1/MAPK and PI3K/AKT/mTOR signaling axis in macrophages.

Determining safe washout period for immune checkpoint inhibitors prior to liver transplantation: An international retrospective cohort study

BACKGROUND AND AIMS

Immune checkpoint inhibitors (ICIs) are increasingly used in patients with advanced HCC patients awaiting liver transplantation (LT). However, concerns about the risk of posttransplant rejection persist.

APPROACH AND RESULTS

We conducted an international retrospective cohort study including 119 HCC patients who received ICIs prior to LT. We analyzed the incidence of allograft rejection, graft loss, and posttransplant recurrence with a particular focus on the washout period between the last ICI dose and LT. In this study, 24 of the 119 (20.2%) patients experienced allograft rejection with a median time to rejection of 9 days (IQR 6-10) post-LT. A linear relationship was observed between shorter washout periods and higher rejection risk. Washout periods <30 days (OR: 21.3, 95% CI: 5.93-103, p< 0.001) and between 30 and 50 days (OR: 9.48, 95% CI 2.47-46.8, p =0.002) were significantly associated with higher rejection rates in the univariate analysis compared to the washout period above 50 days. Graft loss as a result of rejection occurred in 6 patients (25%) with rejection. No factors related to grafts were associated with rejection. A longer washout period was not associated with a lower recurrence-free survival posttransplantation at 36 months (71% vs. 67%, p =0.71).

CONCLUSIONS

Our findings suggest that a washout period longer than 50 days for ICIs before LT appears to be safe with respect to rejection risk. While these results may help guide clinical decision-making, future prospective studies are essential to establish definitive guidelines.

Cytopenias in Autoimmune Liver Diseases-A Review

Autoimmune liver diseases (AiLDs), including autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC), are immune-mediated conditions associated with significant hepatic and systemic manifestations. Among these, cytopenias-defined as reductions in blood cell counts affecting single or multiple lineages-represent a clinically important, though often under-recognized, complication. Cytopenias in AiLDs arise from diverse mechanisms, including immune-mediated destruction, hypersplenism due to portal hypertension, bone marrow suppression, and nutritional deficiencies. These abnormalities can exacerbate bleeding, infections, or fatigue, complicating the disease course and impacting therapeutic strategies. Immune-mediated cytopenias, such as autoimmune hemolytic anemia (AIHA), immune thrombocytopenic purpura (ITP), and autoimmune neutropenia (AIN), are more frequently associated with AIH, whereas cytopenias in PBC and PSC are largely attributed to hypersplenism. Diagnostic evaluation involves a systematic approach combining clinical history, laboratory testing (e.g., complete blood counts, Coombs tests, and nutritional assessments), imaging studies, and bone marrow evaluation in complex cases. Treatment strategies aim to address the underlying cause of cytopenias, including immunosuppressive therapy for autoimmune mechanisms, beta-blockers or splenectomy for hypersplenism, and supplementation for nutritional deficiencies. Challenges include distinguishing between immune- and hypersplenism-related cytopenias, managing drug-induced cytopenias, and optimizing care in transplant candidates. The recently recognized IgG4-related disease, often mimicking cholestatic AiLDs, adds another layer of complexity, given its association with autoimmune cytopenias and hypersplenism. This review aims to act as a guide for the clinician dealing with patients with AiLDs with respect to the occurrence of cytopenias, with a specific focus on pathophysiology and management of these cytopenias. Furthermore, there need to be enhanced multidisciplinary discussions about those patients between the hematologists and hepatologists, with a maintenance of a high index of suspicion for the rarer causes of cytopenias in AiLDs on the part of the treating physician, and there is a need for further studies to elucidate the mechanisms behind the occurrence of cytopenias in AiLDs.

Recurrence of autoimmune liver diseases after liver transplantation: Review and expert opinion statement

Autoimmune liver diseases (AILDs) constitute the fourth most common indication for liver transplantation (LT) across the world. In general, the outcomes after LT are acceptable; however, disease recurrence after LT is common for all AILD, which can negatively affect graft and overall survival. Several questions persist, including the risk factors associated with recurrent disease, optimal antirejection medications, strategies to reduce the risk of recurrence, and how to best incorporate these strategies into clinical practice. For that reason, we assembled an international group of experts to review evidence to address these outstanding questions regarding LT for AILD. Survival rates after LT are ~90% and 70% at 1 and 5 years, and recurrent disease occurs in 10%-50% of patients with AILD. In patients with disease recurrence, graft survival decreased by 18% and 28% and overall survival by 8% and 12% at 5 and 10 years after LT, respectively. Recurrent autoimmune hepatitis is associated with high aminotransferases and immunoglobulin G (IgG) before LT, lymphoplasmacytic infiltrates in the explants, and may be associated with the absence of steroids after LT. However, the efficiency and safety of triple immunosuppressive maintenance therapy is still debatable. Younger age at diagnosis with primary biliary cholangitis or LT is associated with primary biliary cholangitis recurrence. Preventive use of ursodeoxycholic acid reduces the risk of recurrence and has a benefit in graft and patient survival. Episodes of systemic inflammation, including T-cell-mediated rejection, active ulcerative colitis, and episodes of cholangitis, are associated with recurrent PSC. Recurrent disease for AILD is associated with worse graft and patient survival. Patients with autoimmune hepatitis could be considered for long-term low-dose predniso(lo)ne, whereas patients with primary biliary cholangitis should be placed on preventive ursodeoxycholic acid after LT. There are no specific treatments for PSC recurrence; however, adequate control of inflammatory bowel disease and optimal immunosuppression to avoid T-cell-mediated rejection should be encouraged.

GBP1 promotes acute rejection after liver transplantation by inducing Kupffer cells pyroptosis

Liver transplantation is currently recognized as the most effective treatment for severe liver diseases. Although survival rates after liver transplantation have improved, rejection of the transplanted liver remains a significant cause of morbidity and transplant failure in patients. Our team previously discovered a close association between high GBP1 expression and acute rejection reactions following liver transplantation. Liver biopsies were conducted on patients who experienced acute rejection or successfully achieved immune tolerance post-transplantation. We confirmed that GBP1 was highly expressed in the acute rejection group after transplantation by Immunohistochemistry. This study aims to confirm that GBP1 promotes acute rejection reactions following liver transplantation through inducing pyroptosis in rat transplanted hepatic macrophages (KCs). We knocked down GBP1 in KCs and examined the extent of pyroptosis and the severity of acute rejection in the transplanted liver post-orthotopic liver transplantation in rats and KCs. These data provide new approaches for the study of liver transplant rejection reactions and identify new targets.

Liver Transplantation for Hepatocellular Carcinoma: An Expanding Cornerstone of Care in the Era of Immunotherapy

Liver transplantation (LT) has been accepted as a cornerstone of care in hepatocellular carcinoma (HCC) for almost three decades. In recent years, its role has been evolving to include patients with disease burden beyond the widely used Milan criteria. The integration of dynamic biomarkers such as alpha-fetoprotein together with downstaging approaches and tumor evolution after enlistment has allowed the selection of patients most likely to benefit, resulting in 5-year survival rates greater that 70%. With the increasing use of immune checkpoint inhibitors (ICIs) across all stages of disease, alone or in combination with locoregional therapies, there is now the potential to further expand the patient population with HCC who may benefit from LT. This brings challenges, given the global shortage of organs and the need to better understand the optimal use of ICIs before transplantation. Furthermore, the field of transplant oncology awaits additional biomarkers that can predict those likely to benefit from ICIs. More than ever, a multidisciplinary approach for liver cancer management is critical to ensure all patients are considered for LT where appropriate, and do not miss the opportunity for long-term survival.

Advancements in noninvasive techniques for transplant rejection: from biomarker detection to molecular imaging

Transplant rejection remains a significant barrier to the long-term success of organ transplantation. Biopsy, although considered the gold standard, is invasive, costly, and unsuitable for routine monitoring. Traditional biomarkers, such as creatinine and troponin, offer limited predictive value owing to their low specificity, and conventional imaging techniques often fail to detect early organ damage, increasing the risk of undiagnosed rejection episodes. Considering these limitations, emerging noninvasive biomarkers and molecular imaging techniques hold promise for the early and accurate detection of transplant rejection, enabling personalized management strategies. This review highlights noninvasive biomarkers that predict, diagnose, and assess transplant prognosis by reflecting graft injury, inflammation, and immune responses. For example, donor-derived cell-free DNA (dd-cfDNA) is highly sensitive in detecting early graft injury, whereas gene expression profiling effectively excludes moderate-to-severe acute rejection (AR). Additionally, microRNA (miRNA) profiling enhances the diagnostic specificity for precise AR detection. Advanced molecular imaging techniques further augment the monitoring of rejection. Fluorescence imaging provides a high spatiotemporal resolution for AR grading, ultrasound offers real-time and portable monitoring, and magnetic resonance delivers high tissue contrast for anatomical assessments. Nuclear imaging modalities such as single photon emission computed tomography and positron emission tomography, enable dynamic visualization of immune responses within transplanted organs. Notably, dd-cfDNA and nuclear medicine imaging have already been integrated into clinical practice, thereby demonstrating the translational potential of these techniques. Unlike previous reviews, this work uniquely synthesizes advancements in both noninvasive biomarkers and molecular imaging, emphasizing their complementary strengths. Biomarkers deliver molecular-level insights, whereas imaging provides spatial and temporal resolution. Together, they create a synergistic framework for comprehensive and precise transplant monitoring. By bridging these domains, this review underscores their individual contributions and collective potential to enhance diagnostic accuracy, improve patient outcomes, and guide future research and clinical applications in transplant medicine.

Immunosuppression protocols for emerging oncological indications in liver transplantation: A systematic review and pooled analysis

The evolving field of liver transplant (LT) oncology calls for tailored immunosuppression protocols to minimize the risk of tumor recurrence. We systematically reviewed the available evidence from inception to May 2023 regarding immunosuppression protocols used in patients undergoing LT for cholangiocarcinoma, neuroendocrine tumors (NET), hepatic-endothelial hemangioendothelioma, and colorectal liver metastases (CRLM) to identify common practices and to evaluate their association with oncological outcomes. Studies not involving humans, case reports, and short case series (ie, n < 10) were excluded. Among 3374 screened references, we included 117 studies involving 6797 patients distributed as follows: cholangiocarcinoma (58.1%), NETs (18.8%), hepatic-endothelial hemangioendothelioma (7.7%), CRLM (6.8%), mixed neoplasms (6.8%), or others (1.7%). Only 41% of the studies disclosed details of the immunosuppression protocol, and 20.8% of studies provided drug trough concentrations during follow-up. The immunosuppression protocols described were heterogeneous and broadly mirrored routine practices for nontumoral indications. The only exception was CRLM, where tacrolimus minimization-or even withdrawal-in combination with inhibitors of the mammalian target of rapamycin (mTORi) were consistently reported. None of the studies evaluated the relationship between the immunosuppression protocol and oncological outcomes. In conclusion, based on low-quality and indirect scientific evidence, patients with tumoral indications for LT should receive the lowest tacrolimus level tolerated under close surveillance. The combination with mTORi titrated to achieve the top therapeutic range of trough concentrations could allow complete tacrolimus withdrawal. This approach may be particularly useful in patients with cholangiocarcinoma and CRLM, in whom tumor recurrence is the main cause of death. We propose a tool for reporting immunosuppression protocols, which could be implemented in future transplant oncology studies.

EASL Clinical Practice Guidelines on the management of hepatocellular carcinoma

Liver cancer is the third leading cause of cancer-related deaths worldwide, with hepatocellular carcinoma (HCC) accounting for approximately 90% of primary liver cancers. Advances in diagnostic and therapeutic tools, along with improved understanding of their application, are transforming patient treatment. Integrating these innovations into clinical practice presents challenges and necessitates guidance. These clinical practice guidelines offer updated advice for managing patients with HCC and provide a comprehensive review of pertinent data. Key updates from the 2018 EASL guidelines include personalised surveillance based on individual risk assessment and the use of new tools, standardisation of liver imaging procedures and diagnostic criteria, use of minimally invasive surgery in complex cases together with updates on the integrated role of liver transplantation, transitions between surgical, locoregional, and systemic therapies, the role of radiation therapies, and the use of combination immunotherapies at various stages of disease. Above all, there is an absolute need for a multiparametric assessment of individual risks and benefits, considering the patient's perspective, by a multidisciplinary team encompassing various specialties.

Role of immunotherapy in managing cancers prior to liver transplantation

PURPOSE OF REVIEW

Immune checkpoint inhibitors (ICIs) have transformed the treatment landscape in advanced hepatocellular carcinoma and increasingly are being evaluated in earlier stage disease. Herein we explore the role of ICIs pre-liver transplant for liver cancers.

RECENT FINDINGS

Given the high response rates with combination approaches including locoregional treatments, more patients with liver confined disease, without vascular invasion, who have received ICIs are now being rendered eligible for potential liver transplant. This opportunity to expand the population who may benefit from liver transplant has also come with challenges recognizing the global shortage of organs. Post-liver transplant immunosuppression potentially competes with the immune-stimulating effects of ICIs and graft rejection has been a concern. ICIs may provide an opportunity to maintain patients on the waiting list but an understanding of who is likely to benefit is needed, to circumvent possible toxicities. In addition, ICIs are now considered standard of care, in combination with chemotherapy, for advanced cholangiocarcinoma, where the role of liver transplant is evolving.

SUMMARY

As the eligibility criteria globally for liver transplant in the setting of malignancy continues to expand, the integration of ICIs becomes increasingly important.

Advances, challenges and future applications of liver organoids in experimental regenerative medicine

The liver is a vital organ responsible for numerous metabolic processes in the human body, including the metabolism of drugs and nutrients. After liver damage, the organ can rapidly return to its original size if the causative factor is promptly eliminated. However, when the harmful stimulus persists, the liver's regenerative capacity becomes compromised. Substantial theoretical feasibility has been demonstrated at the levels of gene expression, molecular interactions, and intercellular dynamics, complemented by numerous successful animal studies. However, a robust model and carrier that closely resemble human physiology are still lacking for translating these theories into practice. The potential for liver regeneration has been a central focus of ongoing research. Over the past decade, the advent of organoid technology has provided improved models and materials for advancing research efforts. Liver organoid technology represents a novel in vitro culture system. After several years of refinement, human liver organoids can now accurately replicate the liver's morphological structure, nutrient and drug metabolism, gene expression, and secretory functions, providing a robust model for liver disease research. Regenerative medicine aims to replicate human organ or tissue functions to repair or replace damaged tissues, restore their structure or function, or stimulate the regeneration of tissues or organs within the body. Liver organoids possess the same structure and function as liver tissue, offering the potential to serve as a viable replacement for the liver, aligning with the goals of regenerative medicine. This review examines the role of liver organoids in regenerative medicine.

Understanding immunological insights of liver transplantation: a practice for attaining operational tolerance

Liver transplantation has been at the forefront of medical research, with efforts concentrated on understanding the intricate cellular and molecular dynamics involved this complex procedure. This body of work has chronicled critical clinical advancements, identified challenges, and highlighted progressive improvements in surgical practices. These concerted efforts have significantly contributed to the evolution and enhancement of liver transplantation, elevating it to its current level of sophistication. A successful liver transplant now demands an integrated, multidisciplinary approach that includes not only expanding the donor pool from deceased to living donors but also embracing advances in surgical methods, efficiently managing post-transplant complications, and, importantly, achieving operational tolerance. The latter, operational tolerance, is a state wherein the recipient's immune system is coaxed into accepting the transplanted organ without the long-term use of immunosuppressive drugs, thereby minimizing potential side effects, and improving quality of life. Understanding the critical immune mechanisms that aim to prevent graft rejection is essential from an immunological perspective. This review aims to highlight the crucial areas of host versus graft immune responses, making a clear distinction between organs received from living and deceased donors. It examines how these immune responses, both innate and adaptive, are initiated and proposes the exploration of molecular docking sites as a strategy to curb unwanted immune reactions. Additionally, this review explores the promising potential of biomarkers in predicting graft rejection, and emphasizes the importance of achieving tolerance and the continuous quest for innovative strategies to enhance the success and longevity of liver transplants.

Defining an NK Cell-enriched Rejection-like Phenotype in Liver Transplant Biopsies From the INTERLIVER Study

BACKGROUND

Initial analysis of liver transplant biopsies in the INTERLIVER study (ClinicalTrials.gov; unique identifier NCT03193151) using rejection-associated transcripts failed to find an antibody-mediated rejection state (ie, rich in natural killer [NK] cells and with interferon-gamma effects). We recently developed an optimization strategy in lung transplants that isolated an NK cell-enriched rejection-like (NKRL) state that was molecularly distinct from T cell-mediated rejection (TCMR). Here we apply the same strategy to a liver transplant biopsy population.

METHODS

We used this strategy to search for a molecular NKRL state in 765 consented liver transplant biopsies collected at participating international centers for gold-standard histology and molecular assessment by genome-wide microarrays. Validation through a training set-test set approach of an optimized selection of variables as inputs into unsupervised rejection classification identified an NKRL state in livers.

RESULTS

The full model classified 765 biopsies into the following molecular phenotypes, characterized by their gene expression: no-rejection 54%, TCMR 16%, NKRL 13%, and injury 16%. Top TCMR transcripts were expressed in effector T cells; top NKRL transcripts were almost exclusively expressed in NK cells; and both had increased interferon-γ-inducible transcripts, which were more pronounced in TCMR. Most TCMR biopsies had significant parenchymal injury, molecular fibrosis, and abnormal biochemistry. NKRL biopsies had no excess of injury, fibrosis, or biochemistry abnormalities.

CONCLUSIONS

Optimized rejection algorithms indicate that some liver transplants manifest an NKRL state that is well tolerated in the short term postbiopsy and with minimal injury and relatively normal biochemistry, while also underscoring the potential of TCMR to produce extensive parenchymal injury.

Does Weekend Discharge Affect Readmission and Survival in Liver Transplant Patients? Insights From a Cohort Study

BACKGROUND

Weekend hospital discharges are often associated with reduced staffing, potentially impacting the quality of patient care. We studied the effects of weekend discharge after liver transplantation (LT) on early readmission rates, overall survival (OS), and graft survival (GS).

METHOD

We analyzed data from the Ohio State University Wexner Medical Center database (January 2016 to December 2023). The study included initial LT recipients (LTRs) including donation after brain death (DBD) and donation after cardiac death (DCD). Primary outcomes encompassed early readmission rates, and secondary outcomes included OS and GS.

RESULTS

The cohort comprised 915 LTRs (645 DBD, 270 DCD), with 156 (17.0%) weekend and 759 (83.0%) weekday discharges. Regarding discharge disposition, 681 (74.4%) patients were discharged home, 210 (22.9%) were discharged to healthcare facilities. No significant differences were identified in the length of hospital stay (8 days vs. 9 days, weekend vs. weekday, respectively, p = 0.22) or 30-day readmission (29.5% vs. 32.5%, weekend vs. weekday, respectively, p = 0.75). There were no significant differences in OS (90.9% vs. 92.7% at 1-year, 84.4% vs. 88.0% at 3-year, weekend vs. weekday, p = 0.27) and GS (90.9% vs. 91.5% at 1-year, 84.0% vs. 86.6% at 3-year, weekend vs. weekday, p = 0.50). Multivariate logistic analysis showed no significant impact of weekend discharge (OR: 0.84 [0.57-1.22], p = 0.35) or discharge disposition (OR: 1.00 [0.75-1.33], p = 1.00) on 30-day readmission. Multivariate Cox regression analysis found no significant impact of weekend discharge or discharge disposition on OS and GS (all p > 0.05).

CONCLUSION

Weekend discharge does not impact early readmission, OS, or GS in LTRs. These findings are a testament to our multidisciplinary team efforts and suggest that with appropriate discharge planning and follow-up care, the timing of discharge may be less critical than previously assumed.

APASL clinical practice guidelines on systemic therapy for hepatocellular carcinoma-2024

In Asia-Pacific region, hepatocellular carcinoma is a serious health threat attributing to over 600,000 deaths each year and account for over 70% of global cases. Clinically, the major unmet needs are recurrence after curative-intent surgery, liver transplantation or local ablation and disease progression in those with hepatocellular carcinoma not eligible for resection or failed locoregional therapy. In the recent few years, new targeted therapy and immune-checkpoint inhibitors have been registered as systemic therapy to address these issues. Notably, new forms of systemic therapy, either as first-line or second-line therapy for unresectable hepatocellular or those not eligible for locoregional therapy, are now available. New data is also emerging with the use of systemic therapy to prevent hepatocellular carcinoma recurrence after curative-intent resection or local ablation therapy and to retard disease progression after locoregional therapy. In the future, further implementation of immune-checkpoint inhibitors and other forms of immunotherapy are expected to bring a new paradigm to the management of hepatocellular carcinoma. New insight related to immune-related adverse events with the use of immunotherapy has allso enabled optimization of the therapeutic approach to patients with hepatocellular carcinoma. The purpose of this clinical practice guideline is to provide an up-to-date recommendation based on clinical evidence and experience from expert Asia-Pacific key opinion leaders in the field of hepatocellular carcinoma. Three key questions will be addressed, namely: (1) Which patients with hepatocellular carcinoma should be considered for systemic therapy? (2) Which systemic therapy should be used? (3) How should a patient planned for immune checkpoint-based systemic therapy be managed and monitored?

Gene Therapy for Inherited Liver Disease: To Add or to Edit

Patients suffering from an inherited severe liver disorder require lifelong treatment to prevent premature death. Until recently, the only curative treatment option was liver transplantation, which requires lifelong immune suppression. Now, liver-directed gene therapy, which is a much less invasive procedure, has become a market-approved treatment for hemophilia A and B. This may pave the way for it to become the treatment of choice for many other recessive inherited liver disorders with loss-of-function mutations. Inherited liver disease with toxic-gain-of-function or intrinsic hepatocyte damage may require alternative applications, such as integrating vectors or genome editing technologies, that can provide permanent or specific modification of the genome. We present an overview of currently available gene therapy strategies, i.e., gene supplementation, gene editing, and gene repair investigated in preclinical and clinical studies to treat inherited severe liver disorders. The advantages and limitations of these gene therapy applications are discussed in relation to the underlying disease mechanism.

Capecitabine mitigates cardiac allograft rejection via inhibition of TYMS-Mediated Th1 differentiation in mice

OBJECTIVES

Previous studies elucidated that capecitabine (CAP) works as an anti-tumor agent with putative immunosuppressive effects. However, the intricate mechanisms underpinning these effects remain to be elucidated. In this study, we aimed to unravel the molecular pathways by which CAP exerts its immunosuppressive effects to reduce allograft rejection.

METHODS

Hearts were transplanted from male BALB/c donors to male C57BL/6 recipients and treated with CAP for seven days. The rejection of these heart transplants was assessed using a range of techniques, including H&E staining, immunohistochemistry, RNA sequencing, LS-MS/MS, and flow cytometry. In vitro, naïve CD4+ T cells were isolated and cultured under Th1 condition medium with varying treatments, flow cytometry, LS-MS/MS were employed to delineate the role of thymidine synthase (TYMS) during Th1 differentiation.

RESULTS

CAP treatment significantly mitigated acute allograft rejection and enhanced graft survival by reducing graft damage, T cell infiltration, and levels of circulating pro-inflammatory cytokines. Additionally, it curtailed CD4+ T cell proliferation and the presence of Th1 cells in the spleen. RNA-seq showed that TYMS, the target of CAP, was robustly increased post-transplantation in splenocytes. In vitro, TYMS and its metabolic product dTMP were differentially expressed in Th0 and Th1, and were required after activation of CD4+ T cell and Th1 differentiation. TYMS-specific inhibitor, raltitrexed, and the metabolite of capecitabine, 5-fluorouracil, could inhibit the proliferation and differentiation of Th1. Finally, the combined use of CAP and the commonly used immunosuppressant rapamycin can induce long-term survival of allograft.

CONCLUSION

CAP undergoes metabolism conversion to interfere pyrimidine metabolism, which targets TYMS-mediated differentiation of Th1, thereby playing a significant role in mitigating acute cardiac allograft rejection in murine models.

Cardiovascular disease assessment and management in liver transplantation

The prevalence and mortality related to end-stage liver disease (ESLD) continue to rise globally. Liver transplant (LT) recipients continue to be older and have inherently more comorbidities. Among these, cardiac disease is one of the three main causes of morbidity and mortality after LT. Several reasons exist including the high prevalence of associated risk factors, which can also be attributed to the rise in the proportion of patients undergoing LT for metabolic dysfunction-associated steatohepatitis (MASH). Additionally, as people age, the prevalence of now treatable cardiac conditions, including coronary artery disease (CAD), cardiomyopathies, significant valvular heart disease, pulmonary hypertension, and arrhythmias rises, making the need to treat these conditions critical to optimize outcomes. There is an emerging body of literature regarding CAD screening in patients with ESLD, however, there is a paucity of strong evidence to support the guidance regarding the management of cardiac conditions in the pre-LT and perioperative settings. This has resulted in significant variations in assessment strategies and clinical management of cardiac disease in LT candidates between transplant centres, which impacts LT candidacy based on a transplant centre's risk tolerance and comfort level for caring for patients with concomitant cardiac disease. Performing a comprehensive assessment and understanding the potential approaches to the management of ESLD patients with cardiac conditions may increase the acceptance of patients, who appear too complex, but rather require extra evaluation and may be reasonable candidates for LT. The unique physiology of ESLD can profoundly influence preoperative assessment, perioperative management, and outcomes associated with underlying cardiac pathology, and requires a thoughtful multidisciplinary approach. The strategies proposed in this manuscript attempt to review the latest expert experience and opinions and provide guidance to practicing clinicians who assess and treat patients being considered for LT. These topics also highlight the gaps that exist in the comprehensive care of LT patients and the need for future investigations in this field.

The Effects of Sustained Immunosuppression Withdrawal After Liver Transplantation on Metabolic Syndrome

BACKGROUND

Liver transplant (LT) recipients often experience adverse effects of immunosuppressive (IS) drugs, especially on metabolic profiles. Selected LT recipients can achieve successful IS withdrawal; however, its effects on metabolic syndrome (MS) are unknown.

METHODS

This is a retrospective single-center study investigating the incidence and/or regression of MS in 75 selected LT recipients who were previously enrolled in prospective IS withdrawal trials between 1999 and 2017. Patients who were transplanted due to nonalcoholic steatohepatitis/metabolic-associated fatty liver disease were excluded, as well as those with a follow-up <3 y after IS weaning.

RESULTS

Forty-four patients (58.7%) achieved sustained withdrawal or minimization of immunosuppression (WMIS) and 31 patients (41.3%) required reintroduction of immunosuppression (no-WMIS). Among LT recipients who were metabolically healthy (n = 52, 69.3%) before the start of IS weaning, there was a significantly lower rate of de novo MS in WMIS patients compared with no-WMIS patients after 5 y (8.3% and 47.8%, respectively, P  = 0.034). Of 23 LT recipients (30.7%) who had MS at the time of commencing IS withdrawal, complete regression of MS was observed in 47.1% of WMIS patients and in none (0%) of the no-WMIS patients after 5 y ( P  = 0.054). Furthermore, individual components of MS were better controlled in IS-weaned patients, such as arterial hypertension and abnormal serum lipids.

CONCLUSIONS

Achievement of sustained IS withdrawal reduces the incidence of de novo MS development in metabolically healthy patients and increases the likelihood of MS regression in patients with established MS. The foreseeable long-term beneficial effects of these favorable metabolic changes on morbidity and mortality of LT recipients require further investigation.

Liver resection and transplantation in the era of checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) have revolutionised the treatment landscape for advanced hepatocellular carcinoma (HCC). The combination of atezolizumab and bevacizumab has demonstrated efficacy, establishing a new standard of care for advanced HCC. Neoadjuvant studies have shown promising results with high response rates, increasing research into ICIs' role. In the peri-operative setting, in addition to adjuvant and neo-adjuvant therapies, strategies for "downstaging" and "bridging" patients to liver transplantation (LT) are being investigated, broadening the eligible candidate pool. Furthermore, therapeutic advances have reshaped conversion strategies for hepatic resection, with emerging evidence indicating a role for adjuvant immunotherapy in patients at high risk of postoperative recurrence. In LT, concerns have arisen over the potential conflict between immunosuppression needs and the immune-enhancing effects of ICIs, with reports of severe rejection. However, liver-specific factors may lessen rejection risks, prompting exploration into the safety of pre-transplant ICI administration. Moreover, ongoing trials must prioritise patient selection and vigilant management protocols. Despite the remarkable progress in immunotherapy, the intricate molecular interactions within the tumour microenvironment and their implications on oncogenic pathways remain incompletely understood. This highlights the need for specialised expertise to effectively integrate immunotherapy into the surgical management of HCC. Key challenges include ensuring safety, optimising oncological outcomes, managing the risk of graft rejection in transplant recipients, and refining patient selection criteria. In this review, we aim to provide a comprehensive overview of the evolving role of immunotherapy in the surgical management of HCC, discussing the rationale for its application in both pre- and post-surgical contexts, leveraging current clinical experience, identifying potential limitations, and envisioning future applications. By integrating existing knowledge and highlighting areas for further investigation, this review seeks to inform clinical practice and guide future research endeavours.

Key genes and immune pathways in T-cell mediated rejection post-liver transplantation identified via integrated RNA-seq and machine learning

Liver transplantation is the definitive treatment for end-stage liver disease, yet T-cell mediated rejection (TCMR) remains a major challenge. This study aims to identify key genes associated with TCMR and their potential biological processes and mechanisms. The GSE145780 dataset was subjected to differential expression analysis, weighted gene co-expression network analysis (WGCNA), and machine learning algorithms to pinpoint key genes associated with TCMR. Gene Set Enrichment Analysis (GSEA), immune infiltration analysis, and regulatory networks were constructed to ascertain the biological relevance of these genes. Expression validation was performed using single-cell RNA-seq (scRNA-seq) data and liver biopsy tissues from patients. We identified 5 key genes (ITGB2, FCER1G, IL-18, GBP1, and CD53) that are associated with immunological functions, such as chemotactic activity, antigen processing, and T cell differentiation. GSEA highlighted enrichment in chemokine signaling and antigen presentation pathways. A lncRNA-miRNA-mRNA network was delineated, and drug target prediction yielded 26 potential drugs. Evaluation of expression levels in non-rejection (NR) and TCMR groups exhibited significant disparities in T cells and myeloid cells. Tissue analyses from patients corroborated the upregulation of GBP1, IL-18, CD53, and FCER1G in TCMR cases. Through comprehensive analysis, this research has identified 4 genes intimately connected with TCMR following liver transplantation, shedding light on the underlying immune activation pathways and suggesting putative targets for therapeutic intervention.

Prognostic scores for ursodeoxycholic acid-treated patients predict graft loss and mortality in recurrent primary biliary cholangitis after liver transplantation

BACKGROUND & AIMS

Recurrent primary biliary cholangitis (rPBC) develops in approximately 30% of patients and negatively impacts graft and overall patient survival after liver transplantation (LT). There is a lack of data regarding the response rate to ursodeoxycholic acid (UDCA) in rPBC. We evaluated a large, international, multi-center cohort to assess the performance of PBC scores in predicting the risk of graft and overall survival after LT in patients with rPBC.

METHODS

A total of 332 patients with rPBC after LT were evaluated from 28 centers across Europe, North and South America. The median age at the time of rPBC was 58.0 years [IQR 53.2-62.6], and 298 patients (90%) were female. The biochemical response was measured with serum levels of alkaline phosphatase (ALP) and bilirubin, and Paris-2, GLOBE and UK-PBC scores at 1 year after UDCA initiation.

RESULTS

During a median follow-up of 8.7 years [IQR 4.3-12.9] after rPBC diagnosis, 52 patients (16%) had graft loss and 103 (31%) died. After 1 year of UDCA initiation the histological stage at rPBC (hazard ratio [HR] 3.97, 95% CI 1.36-11.55, p = 0.01), use of prednisone (HR 3.18, 95% CI 1.04-9.73, p = 0.04), ALP xULN (HR 1.59, 95% CI 1.26-2.01, p <0.001), Paris-2 criteria (HR 4.14, 95% CI 1.57-10.92, p = 0.004), GLOBE score (HR 2.82, 95% CI 1.71-4.66, p <0.001), and the UK-PBC score (HR 1.06, 95% CI 1.03-1.09, p <0.001) were associated with graft survival in the multivariate analysis. Similar results were observed for overall survival.

CONCLUSION

Patients with rPBC and disease activity, as indicated by standard PBC risk scores, have impaired outcomes, supporting efforts to treat recurrent disease in similar ways to pre-transplant PBC.

IMPACT AND IMPLICATIONS

One in three people who undergo liver transplantation for primary biliary cholangitis develop recurrent disease in their new liver. Patients with recurrent primary biliary cholangitis and incomplete response to ursodeoxycholic acid, according to conventional prognostic scores, have worse clinical outcomes, with higher risk of graft loss and mortality in similar ways to the disease before liver transplantation. Our results supportsupport efforts to treat recurrent disease in similar ways to pre-transplant primary biliary cholangitis.

Mesenchymal stem cell therapy for liver transplantation: clinical progress and immunomodulatory properties

Although liver transplantation (LT) is an effective strategy for end-stage liver diseases, the shortage of donor organs and the immune rejection hinder its widespread implementation in clinical practice. Mesenchymal stem cells (MSCs) transplantation offers a promising approach for patients undergoing liver transplantation due to their immune regulatory capabilities, hepatic protection properties, and multidirectional differentiation potential. In this review, we summarize the potential applications of MSCs transplantation in various LT scenarios. MSCs transplantation has demonstrated effectiveness in alleviating hepatic ischemia-reperfusion injury, enhancing the viability of liver grafts, preventing acute graft-versus-host disease, and promoting liver regeneration in split LT therapy. We also discuss the clinical progress, and explore the immunomodulatory functions of MSCs in response to both adaptive and innate immune responses. Furthermore, we emphasize the interactions between MSCs and different immune cells, including T cells, B cells, plasma cells, natural killer cells, dendritic cells, Kupffer cells, and neutrophils, to provide new insights into the immunomodulatory properties of MSCs in adoptive cell therapy.

Rethinking Immune Check Point Inhibitors Use in Liver Transplantation: Implications and Resistance

Immune checkpoint inhibitors (ICIs) have revolutionized cancer therapy, including the two most common liver tumors, hepatocellular carcinoma and cholangiocarcinoma, but their use in the peri-transplantation period is controversial. ICI therapy aims to heighten cytotoxic T lymphocytes response against tumors. However, tumor recurrence is common owing to tumor immune response escape involving ablation of CTL response by interfering with antigen presentation, triggering CLT apoptosis and inducing epigenetic changes that promote ICI therapy resistance. ICI can also affect tissue resident memory T cell population, impact tolerance in the post-transplant period, and induce acute inflammation risking graft survival post-transplant. Their interaction with immunosuppression may be key in reducing tumor burden and may thus, require multimodal therapy to treat these tumors. This review summarizes ICI use in the liver transplantation period, their impact on tolerance and resistance, and new potential therapies for combination or sequential treatments for liver tumors.

CpG adjuvant enhances humoral and cellular immunity against OVA in different degrees in BALB/c, C57BL/6J, and C57BL/6N mice

In lab settings, inbred mouse strains like BALB/c, C57BL/6J, and C57BL/6N are commonly used. Research in immunology and infectious diseases indicates that their Th1 and Th2 immune responses differ. However, the specific differences in the immune response to the vaccination still require investigation. In this study, ovalbumin (OVA) was used as an antigen and CpG-enriched recombinant plasmid (pUC18-CpG) as an adjuvant for immunisation. The level of serum-specific antibody IgG was detected by indirect ELISA. At 35dpi, serum cytokine levels were measured using MILLIPLEX®. T lymphocyte clusters from mouse spleen were examined using flow cytometry to investigate the immunological effects of the CPG-OVA vaccine on three different types of mice. The results showed that pUC18-CpG as an adjuvant could successfully enhance the immune response. BALB/c had the highest level of IgG antibody. In the OVA-only group, the CD4+/CD8+ ratio of the three types of mice was generally increased, and the BALB/c group had the highest ratio. After inoculation with CpG-OVA, the CD4+/CD8+ ratio of the three types of mice was lower than that of the OVA-only group, and C57BL/6J was the lowest. Compared with the CpG-OVA group of the three kinds of mice, the levels of Th2 cytokines IL-6 and IL-10 in BALB/c were increased compared with C57BL/6J and C57BL/6N. After OVA, the six cytokines secreted in C57BL/6J were higher than those in the C57BL/6N OVA group. Therefore, C57 is a better model for examining the function of the vaccine in cellular immunity, whereas BALB/c mice are more prone to humoral immunity. In addition to highlighting the CpG plasmid's ability to successfully activate the immune response of Th1 and Th2, as well as the expression of IgG in vivo and promote T cell immune typing, this study provides valuable insights into immunology and the selection of mouse models for infectious diseases, providing a valuable resource for designing more effective vaccines in the future.

The First Case of Intra-portal Islet Implantation During Liver Machine Perfusion Allowing Simultaneous Islet-liver Transplantation in A Human: A New and Safe Treatment for End-stage Liver Disease Combined With Diabetes Mellitus

OBJECTIVE

Evaluating the safety and efficacy of implanting a liver with islet grafts into patients with end-stage liver disease and diabetes mellitus (DM).

BACKGROUND

DM and end-stage liver diseases are significant health concern worldwide, often coexisting and mutually influencing each other. Addressing both diseases simultaneously is paramount.

METHODS

We utilized the islet transplantation combined ischemia-free liver transplantation (ITIFLT) technique to treat a patient with hepatocellular carcinoma (HCC) and type 2 diabetes mellitus (T2DM). The liver was procured and preserved using the ischemia-free liver transplantation (IFLT) technique, and during normothermic machine perfusion (NMP), isolated and purified islet grafts were transplanted into the liver through the portal vein. Finally, the liver, incorporating with the transplant islet grafts, was implanted into the recipient without interruption of blood supply.

RESULTS

The patient received both liver and islet graft from the same donor. The patient achieved insulin-independence by post-transplant day (PTD) 9, and both liver and islet function remained robust. The patient was discharged on PTD 18 and experienced no surgical or transplantation-related complications during the follow-up period. Furthermore, islet grafts presence was observed in liver biopsies after islet transplantation.

CONCLUSIONS

This landmark case marks the inaugural application of ITIFLT in humans, signifying its potential as a promising treatment modality for end-stage liver disease with DM.

Challenges in Liver Transplantation for Hepatocellular Carcinoma: A Review of Current Controversies

Liver transplantation (LT) remains one of the most effective treatments for hepatocellular carcinoma (HCC) and significantly enhances patient survival. However, the application of LT for HCC faces challenges owing to advancements in cancer-specific treatment modalities and the increased burden of patients' comorbidities. This narrative review explores current controversies and advancements in LT for HCC. Key areas of focus include the management of comorbidities and patient education by advanced practice nurses, impacts of frailty on waitlists and post-LT outcomes, selection criteria for LT in the era of new downstaging tools, role of radiology in patient selection, and implications of potential immunotherapy use both before and after LT. Additionally, the importance of immunosuppression management with strategies aimed at minimizing rejection while considering the risk of HCC recurrence and the role of surveillance for HCC recurrence is highlighted. This review also underscores the importance of a multidisciplinary approach for optimizing outcomes in patients with HCC undergoing LT.

Establishment and validation of a predictive model of immune tolerance after pediatric liver transplantation: a multicenter cohort study

Background:

Side-effect of life-long immunosuppressants (IS) administration is a major obstacle for the long-term survival of pediatric liver transplantation (LT) recipients. Immunotolerance is the status that recipients discontinued IS with normal liver function and intrahepatic histology. So far, only a few clinical parameters were identified related with tolerance but failed to accurately discriminate tolerant recipients in clinical practice. Here, the authors aimed to provide a comprehensive view of pre-LT and post-LT risk factors associated with the achievement of tolerance after pediatric LT and established a tolerance predictive nomogram (ITPLT) with high accuracy and specificity.

Methods:

The authors enrolled 2228 pediatric recipients who received LT in Renji Hospital between October 2006 and December 2020. All participants survived over 3 years after transplantation with comprehensive and intact medical history and follow-up data. They were randomly assigned to training and validation cohorts in accordance with a ratio of 1:1. Univariate and multivariable Logistic regression were used to identify clinical factors associated with post-LT immune tolerance and establish a predictive model. The model was further validated in an independent external validation cohort from Tianjin First Central Hospital.

Results:

Among all participants, 6% recipients successfully tapered IS with intact allograft function. The most common reason for IS discontinuity was pneumonia. Univariate analysis identified 15 clinical factors associated with tolerance achievement, including age at LT, follow-up time, preoperative total bilirubin, creatinine, INR, CYP polymorphism, types of transplantation, massive postoperative ascites, episodes of acute rejection, and the severity of EBV and CMV infection. Using multivariable Logistic regression, the authors established the predictive ITPLT model for post-LT tolerance, which included seven easily accessible clinical factors (age at LT, CYP3A5 genotype, types of transplantation, post-LT massive ascites, preoperative INR, creatinine, and total bilirubin levels). Then, the authors visualized the model using nomogram. The c -statistics for predicting tolerance achievement in the training, internal validation, and external validation cohorts were 0.854, 0.787, and 0.746, respectively.

Conclusion:

Multiple pre-LT and post-LT clinical factors affected the process of immune remodeling after pediatric LT. The predictive ITPLT model, composed of seven easily accessible clinical factors, could comprehensively reveal the effect of these clinical parameters on immune remodeling and accurately identify tolerant recipients after pediatric LT. The application of ITPLT could facilitate the individualized IS strategy in the future.

EASL-EASD-EASO Clinical Practice Guidelines on the management of metabolic dysfunction-associated steatotic liver disease (MASLD)

Metabolic dysfunction-associated steatotic liver disease (MASLD), previously termed non-alcoholic fatty liver disease (NAFLD), is defined as steatotic liver disease (SLD) in the presence of one or more cardiometabolic risk factor(s) and the absence of harmful alcohol intake. The spectrum of MASLD includes steatosis, metabolic dysfunction-associated steatohepatitis (MASH, previously NASH), fibrosis, cirrhosis and MASH-related hepatocellular carcinoma (HCC). This joint EASL-EASD-EASO guideline provides an update on definitions, prevention, screening, diagnosis and treatment for MASLD. Case-finding strategies for MASLD with liver fibrosis, using non-invasive tests, should be applied in individuals with cardiometabolic risk factors, abnormal liver enzymes, and/or radiological signs of hepatic steatosis, particularly in the presence of type 2 diabetes (T2D) or obesity with additional metabolic risk factor(s). A stepwise approach using blood-based scores (such as FIB-4) and, sequentially, imaging techniques (such as transient elastography) is suitable to rule-out/in advanced fibrosis, which is predictive of liver-related outcomes. In adults with MASLD, lifestyle modification - including weight loss, dietary changes, physical exercise and discouraging alcohol consumption - as well as optimal management of comorbidities - including use of incretin-based therapies (e.g. semaglutide, tirzepatide) for T2D or obesity, if indicated - is advised. Bariatric surgery is also an option in individuals with MASLD and obesity. If locally approved and dependent on the label, adults with non-cirrhotic MASH and significant liver fibrosis (stage ≥2) should be considered for a MASH-targeted treatment with resmetirom, which demonstrated histological effectiveness on steatohepatitis and fibrosis with an acceptable safety and tolerability profile. No MASH-targeted pharmacotherapy can currently be recommended for the cirrhotic stage. Management of MASH-related cirrhosis includes adaptations of metabolic drugs, nutritional counselling, surveillance for portal hypertension and HCC, as well as liver transplantation in decompensated cirrhosis.