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Chronic kidney disease (CKD) is a major complication of liver transplantation (LT) associated with substantial morbidity and mortality. Knowing the drivers of post-LT kidney dysfunction-with a granular focus on the type, duration, and severity of pre-LT kidney disease-can highlight intervention opportunities and inform dual-organ allocation policies. We retrospectively analyzed predictors of safety net kidney after liver transplant (KALT) eligibility and kidney replacement therapy (KRT) for > 14 days after LT. Among 557 recipients of adult deceased-donor LT, 49% had normal kidney function, 25% had acute kidney injury (AKI), and 25% had CKD±AKI at the time of LT. A total of 36 (6.5%) qualified for KALT and 63 (11%) required KRT > 14 days. In univariable analysis, factors associated with KALT eligibility and KRT > 14 days, respectively, included stage 3 AKI (OR 7.87; OR 7.06), CKD±AKI (OR 4.58; OR 4.22), CKD III-V duration (OR 1.10 per week; OR 1.06 per week), and increasing CKD stage (stage III: OR 3.90, IV: OR 5.24, V: OR 16.8; stage III: OR 2.23, IV: OR 3.62, V: OR 19.4). AKI stage I-II and AKI duration in the absence of CKD were not associated with the outcomes. Pre-LT KRT had a robust impact on KALT eligibility (OR 4.00 per week) and prolonged post-LT KRT (OR 5.22 per week), with 19.8% of patients who received any pre-LT KRT ultimately qualifying for KALT. Eligibility for KALT was similar between those who received 0 days and ≤ 14 days of KRT after LT (2.1% vs. 2.9%, p = 0.53). In conclusion, the type, duration, and severity of pre-LT kidney dysfunction have unique impacts on post-LT kidney-related morbidity, and future research must use these novel classifications to study mitigation strategies., (Copyright © 2024 American Association for the Study of Liver Diseases.)

Over the last 50 years, liver transplantation has evolved into a procedure routinely performed in many countries worldwide. Those able to access this therapy frequently experience a miraculous risk-benefit ratio, particularly if they face the imminently life-threatening disease. Over the decades, the success of liver transplantation, with dramatic improvements in early posttransplant survival, has aggressively driven demand. However, despite the emergence of living donors to augment deceased donors as a source of organs, supply has lagged far behind demand. As a result, rationing has been an unfortunate focus in recent decades. Recent shifts in the epidemiology of liver disease combined with transformative innovations in liver preservation suggest that the underlying premise of organ shortage may erode in the foreseeable future. The focus will sharpen on improving equitable access while mitigating constraints related to workforce training, infrastructure for organ recovery and rehabilitation, and their associated costs. Research efforts in liver preservation will undoubtedly blossom with the aim of optimizing both the timing and conditions of transplantation. Coupled with advances in genetic engineering, regenerative biology, and cellular therapies, the portfolio of innovation, both broad and deep, offers the promise that, in the future, liver transplantation will not only be broadly available to those in need but also represent a highly durable life-saving therapy., (Copyright © 2024 American Association for the Study of Liver Diseases.)

Background: Early allograft dysfunction (EAD) is a common complication after liver transplantation (LT) and is associated with poor prognosis. Graft itself plays a major role in the development of EAD. We aimed to reveal the EAD-specific molecular profiles to assess graft quality and establish EAD predictive models., Methods: A total of 223 patients who underwent LT were enrolled and divided into training ( n =73) and validation ( n =150) sets. In the training set, proteomics was performed on graft biopsies, together with metabolomics on paired perfusates. Differential expression, enrichment analysis, and protein-protein interaction network were used to identify the key molecules and pathways involved. EAD predictive models were constructed using machine learning and verified in the validation set., Results: A total of 335 proteins were differentially expressed between the EAD and non-EAD groups. These proteins were significantly enriched in triglyceride and glycerophospholipid metabolism, neutrophil degranulation, and the MET-related signaling pathway. The top 12 graft proteins involved in the aforementioned processes were identified, including GPAT1, LPIN3, TGFB1, CD59, and SOS1. Moreover, downstream metabolic products, such as lactate dehydrogenase, interleukin-8, triglycerides, and the phosphatidylcholine/phosphorylethanolamine ratio in the paired perfusate displayed a close relationship with the graft proteins. To predict the occurrence of EAD, an integrated model using perfusate metabolic products and clinical parameters showed areas under the curve of 0.915 and 0.833 for the training and validation sets, respectively. It displayed superior predictive efficacy than that of currently existing models, including donor risk index and D-MELD scores., Conclusions: We identified novel biomarkers in both grafts and perfusates that could be used to assess graft quality and provide new insights into the etiology of EAD. Herein, we also offer a valid tool for the early prediction of EAD., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

The Banff Working Group on Liver Allograft Pathology met in September 2022. Participants included hepatologists, surgeons, pathologists, immunologists, and histocompatibility specialists. Presentations and discussions focused on the evaluation of long-term allograft health, including noninvasive and tissue monitoring, immunosuppression optimization, and long-term structural changes. Potential revision of the rejection classification scheme to better accommodate and communicate late T cell-mediated rejection patterns and related structural changes, such as nodular regenerative hyperplasia, were discussed. Improved stratification of long-term maintenance immunosuppression to match the heterogeneity of patient settings will be central to improving long-term patient survival. Such personalized therapeutics are in turn contingent on a better understanding and monitoring of allograft status within a rational decision-making approach, likely to be facilitated in implementation with emerging decision-support tools. Proposed revisions to rejection classification emerging from the meeting include the incorporation of interface hepatitis and fibrosis staging. These will be opened to online testing, modified accordingly, and subject to consensus discussion leading up to the next Banff conference., Competing Interests: Declaration of competing interest The authors of this manuscript have conflicts of interest to disclose as described by the American Journal of Transplantation. Annette Jackson: HLA consultant (Hansa Biopharma); Research reagents/grant (CareDx); Speaker bureau (One Lambda/ThermoFisher). Josh Levitsky: Advisor (Eurofins; eGenesis); Speaker for Takeda; Mallinckrodt. Richard Taubert: Research grant (Oncocyte/Chronix Biomedical). The other authors have no conflict of interest to disclose., (Crown Copyright © 2024. Published by Elsevier Inc. All rights reserved.)

Background: Portal hypertension (PHT) has been proven to be closely related to the development of hepatocellular carcinoma (HCC). Whether PHT before liver transplantation (LT) will affect the recurrence of HCC is not clear., Methods: 110 patients with depressurization of the portal vein (DPV) operations (Transjugular Intrahepatic Portosystemic Shunt-TIPS, surgical portosystemic shunt or/and splenectomy) before LT from a HCC LT cohort, matched with 330 preoperative non-DPV patients; this constituted a nested case-control study. Subgroup analysis was based on the order of DPV before or after the occurrence of HCC., Results: The incidence of acute kidney injury and intra-abdominal bleeding after LT in the DPV group was significantly higher than that in non-DPV group. The 5-year survival rates in the DPV and non-DPV group were 83.4% and 82.7% respectively (P = 0.930). In subgroup analysis, patients in the DPV prior to HCC subgroup may have a lower recurrence rate (4.7% vs.16.8%, P = 0.045) and a higher tumor free survival rate (88.9% vs.74.4%, P = 0.044) after LT under the up-to-date TNMI-II stage, while in TNM III stage, there was no difference for DPV prior to HCC subgroup compared with the DPV after HCC subgroup or the non-DPV group., Conclusion: Compared with DPV after HCC, DPV treatment before HCC can reduce the recurrence rate of HCC after early transplantation (TNM I-II). DPV before LT can reduce the recurrence of early HCC., (© 2024. The Author(s).)

Background & Aims: Successful immunosuppression withdrawal (ISW) is possible for a subfraction of liver transplant (LT) recipients but the factors that define the risk of ISW failure are largely unknown. One candidate prognostic factor for ISW success or operational tolerance (OT) is longer time between LT and ISW which we term "pre-withdrawal time". To clarify the impact of pre-withdrawal time span on subsequent ISW success or failure, we conducted a systematic review with meta-analysis., Methods: We systematically interrogated the literature for LT recipient ISW studies reporting pre-withdrawal time. Eligible articles from Embase, Medline, and the Cochrane Central Register of Controlled Trials were used for backward and forward citation searching. Pre-withdrawal time individual patient data (IPD) was requested from authors. Pooled mean differences and time-response curves were calculated using random-effects meta-analyses., Results: We included 17 studies with 691 patients, 15 of which (620 patients) with IPD. Study-level risk of bias was heterogeneous. Mean pre-withdrawal time was greater by 427 days [95% confidence interval (CI) 67-788] in OT compared to non-OT patients. This increase was potentiated to 799 days (95% CI 369-1229) or 1074 days (95% CI 685-1463) when restricting analysis to adult or European study participants. In time-response meta-analysis for adult or European ISW candidates, likelihood of OT increased by 7% (95% CI 4-10%) per year after LT (GRADE low- and moderate-certainty of evidence, respectively)., Conclusions: Our data support the impact of pre-withdrawal time in ISW decision-making for adult and European LT recipients., Prospero Registration: CRD42021272995., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Caregivers of children who have had liver transplantation often experience chronic care stress. Previous studies have focused on caregivers' negative feelings (e.g., caregiver burden), but few studies have focused on caregivers' positive feelings (e.g., sense of coherence) and caregiver ability., Objectives: The study purpose was to investigate the status of the burden of caregivers of children with liver transplantation, and to explore the mediating role of sense of coherence between caregiver ability and caregiver burden., Methods: There were 461 questionnaires collected from a tertiary-level hospital from caregivers of children who had liver transplantation from April to June 2022. Demographic data, Family Caregiver Task Inventory, Sense of Coherence Scale-13, and Zarit Burden Interview were used. The STROBE checklist was monitored., Results: The average caregiver burden score was 32.19 ± 16.71. The distribution of caregiver burden levels was mild (42.52%), none (26.25%), moderate (24.95%), and severe (6.29%). Caregiver ability score was negatively correlated with caregiver burden score; however, sense of coherence score was negatively correlated with caregiver burden score. Caregiver ability partially mediated caregiver burden through sense of coherence (38.51%)., Conclusion: The caregiver burden level was not heavy in general. Both positive and negative feelings were present in caregivers. Caregiver ability also reduced the caregiver burden through sense of coherence., Competing Interests: Declaration of Competing Interest The authors declare that they have no conflict of interests., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Outcome data for the great majority of liver normothermic machine perfusion (NMP) cases derive from the strict confines of clinical trials. Detailed specifics regarding the intraoperative and early postoperative impact of NMP on reperfusion injury and its sequelae during real-world use of this emerging technology remain largely unavailable., Methods: We analyzed transplants performed in a 3-month pilot period during which surgeons invoked commercial NMP at their discretion. Living donor, multi-organ, and hypothermic machine perfusion transplants were excluded., Results: Intraoperatively, NMP (n = 24) compared to static cold storage (n = 25) recipients required less peri-reperfusion bolus epinephrine (0 vs. 60 μg; p < .001) and post-reperfusion fresh frozen plasma (2.5 vs. 7.0 units; p = .0069), platelets (.0 vs. 2.0 units; p = .042), and hemostatic agents (0% vs. 24%; p = .010). Time from incision to venous reperfusion did not differ (3.6 vs. 3.1; p = .095) but time from venous reperfusion to surgery end was shorter for NMP recipients (2.3 vs. 2.8 h; p = .0045). Postoperatively, NMP recipients required fewer red blood cell (1.0 vs. 4.0 units; p = .0083) and fresh frozen plasma (4.0 vs. 7.0 units; p = .046) transfusions, had shorter intensive care unit stays (33.5 vs. 58.4 h; p = .012), and experienced less early allograft dysfunction according to both the Model for Early Allograft Function Score (3.4 vs. 5.0; p = .0047) and peak AST within 10 days of transplant (619 vs. 1,181 U/L; p = .036). Liver acceptance for the corresponding recipient was conditional on NMP use for 63% (15/24) of cases., Conclusion: Real-world NMP use was associated with significantly lower intensity of reperfusion injury and intraoperative and postoperative care that may translate into patient benefit., (© 2023 The Authors. Clinical Transplantation published by John Wiley & Sons Ltd.)

Introduction: Donation after circulatory death (DCD) liver transplantation (LT) makes up well less than 1% of all LTs with a Model for End-Stage Liver Disease (MELD)≥35 in the United States. We hypothesized DCD-LT yields acceptable ischemia-reperfusion and reasonable outcomes for recipients with MELD≥35., Methods: We analyzed recipients with lab-MELD≥35 at transplant within the UCSF (n=41) and the UNOS (n=375) cohorts using multivariate Cox regression and propensity score matching., Results: In the UCSF cohort, five-year patient survival was 85% for DCD-LTs and 86% for matched-Donation after Brain Death donors-(DBD) LTs (p=0.843). Multivariate analyses showed that younger donor/recipient age and more recent transplants (2011-2021 versus 1999-2010) were associated with better survival. DCD vs. DBD graft use did not significantly impact survival (HR: 1.2, 95%CI 0.6-2.7). The transaminase peak was approximately doubled, indicating suggesting an increased ischemia-reperfusion hit. DCD-LTs had a median post-LT length of stay of 11 days, and 34% (14/41) were on dialysis at discharge versus 12 days and 22% (9/41) for DBD-LTs. 27% (11/41) DCD-LTs versus 12% (5/41) DBD-LTs developed a biliary complication (p=0.095). UNOS cohort analysis confirmed patient survival predictors, but DCD graft emerged as a risk factor (HR: 1.5, 95%CI 1.3-1.9) with five-year patient survival of 65% versus 75% for DBD-LTs (p=0.016). This difference became non-significant in a sub-analysis focusing on MELD 35-36 recipients. Analysis of MELD≥35 DCD recipients showed that donor age of <30yo independently reduced the risk of graft loss by 30% (HR, 95%CI: 0.7 (0.9-0.5), p=0.019). Retransplant status was associated with a doubled risk of adverse event (HR, 95%CI: 2.1 (1.4-3.3), p=0.001). The rejection rates at 1y were similar between DCD- and DBD-LTs, (9.3% (35/375) versus 1,541 (8.7% (1,541/17,677), respectively)., Discussion: In highly selected recipient/donor pair, DCD transplantation is feasible and can achieve comparable survival to DBD transplantation. Biliary complications occurred at the expected rates. In the absence of selection, DCD-LTs outcomes remain worse than those of DBD-LTs., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Meier, Nunez, Syed, Feng, Tavakol, Freise, Roberts, Ascher, Hirose and Roll.)

Introduction: Although clinicians repeatedly measure ALT to assess allograft health in children with liver transplants, they generally make decisions based on single values or qualitative trends without quantitative aggregation or synthesis. We therefore aimed to derive and test a holistic ALT metric for the 5th post-transplant year (Yr 4-5) that may better guide clinical decision-making and/or population comparisons., Methods: We derived the "adjusted mean Yr 4-5 ALT" for children transplanted in 2005-2016 by averaging the median ALT from each month. Patients in quartiles (Q1-4) defined by the adjusted mean Yr 4-5 ALT were compared by clinical variables, Yr 5-8 outcomes, and tacrolimus standard deviation (MLVI)., Results: For 97 children [49 male; 77 deceased donors; median (IQR) age at LT 2.5 (0.8-11.7) years], the 25th, 50th, and 75th percentile thresholds for adjusted mean Yr 4-5 ALT were 19, 28, and 47 U/L, respectively. Age, donor type, LT indication, rejection history, and mean tacrolimus levels did not differ between quartiles (Q). Children in Q4 had more Yr 4-5 acute rejection episodes (p < .01), higher Yr 4-5 MLVI (p < .01), and more Yr 5-8 for-cause liver biopsies (p < .01) than those in Q1 + Q2. Children in Q3 also had higher Yr 4-5 MLVI than Q1 + Q2 (p = .047). Rates of chronic rejection and therapeutic liver-related procedures were higher in Q4 but the difference did not reach significance., Conclusion: An integrated ALT metric calculated utilizing all available ALT values correlates with MLVI and future for-cause biopsies. Further study of this novel ALT metric as a predictor of clinical outcomes and descriptor of populations is warranted., (© 2023 Wiley Periodicals LLC.)

Outcomes after liver transplantation have continuously improved over the past decades, but long-term survival rates are still lower than in the general population. The liver has distinct immunological functions linked to its unique anatomical configuration and to its harbouring of a large number of cells with fundamental immunological roles. The transplanted liver can modulate the immunological system of the recipient to promote tolerance, thus offering the potential for less aggressive immunosuppression. The selection and adjustment of immunosuppressive drugs should be individualised to optimally control alloreactivity while mitigating toxicities. Routine laboratory tests are not accurate enough to make a confident diagnosis of allograft rejection. Although several promising biomarkers are being investigated, none of them is sufficiently validated for routine use; hence, liver biopsy remains necessary to guide clinical decisions. Recently, there has been an exponential increase in the use of immune checkpoint inhibitors due to the unquestionable oncological benefits they provide for many patients with advanced-stage tumours. It is expected that their use will also increase in liver transplant recipients and that this might affect the incidence of allograft rejection. Currently, the evidence regarding the efficacy and safety of immune checkpoint inhibitors in liver transplant recipients is limited and cases of severe allograft rejection have been reported. In this review, we discuss the clinical relevance of alloimmune disease, the role of minimisation/withdrawal of immunosuppression, and provide practical guidance for using checkpoint inhibitors in liver transplant recipients., (Copyright © 2023 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Background: For children with liver transplants (LT), achieving an "ideal outcome" is a balancing act: too little immunosuppression begets graft injury; too much begets systemic complications. We aimed to delineate the parental perspective on this tightrope., Methods: Parents of children with LT completed an internet-based survey about their child's immunosuppression., Results: Children of respondents (n = 82) were a median 4 years from primary LT (range 0-22); 73% were on immunosuppression monotherapy. Parents' top concerns were related to immunosuppression complications; 46% were more concerned about immunosuppression complications than rejection; only 17% were more concerned about rejection than immunosuppression complications. Among parents of children on immunosuppression monotherapy, 29% still worried more about immunosuppression complications than rejection, 48% expressed equal concern for both. Time since LT (0-4 vs. >4 years) was not associated with concern level for rejection or immunosuppression complications. Caregivers were significantly more certain that their child's immunosuppression regimen was correct to prevent rejection than to mitigate complications (p < .005)., Conclusion: Caregivers of children with LTs reported higher levels of concern and uncertainty about immunosuppression complications than rejection risk. Understanding parent and patient perspectives on IS, and incorporating them into immunosuppression counseling and decision-making, is critical to achieving truly "ideal" long-term outcomes., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Liver transplantation (LT) is the most effective treatment for various end-stage liver diseases. However, the cellular complexity and intercellular crosstalk of the transplanted liver have constrained analyses of graft reconstruction after LT., Methods: We established an immune-tolerated orthotopic LT mouse model to understand the physiological process of graft recovery and intercellular crosstalk. We employed single-cell RNA sequencing and cytometry by time-of-flight to comprehensively reveal the cellular landscape., Results: We identified an acute and stable phase during perioperative graft recovery. Using single-cell technology, we made detailed annotations of the cellular landscape of the transplanted liver and determined dynamic modifications of these cells during LT. We found that 96% of graft-derived immune cells were replaced by recipient-derived cells from the preoperative to the stable phase. However, CD206 + MerTK + macrophages and CD49a + CD49b - natural killer cells were composed of both graft and recipient sources even in the stable phase. Intriguingly, the transcriptional profiles of these populations exhibited tissue-resident characteristics, suggesting that recipient-derived macrophages and natural killer cells have the potential to differentiate into 'tissue-resident cells' after LT. Furthermore, we described the transcriptional characteristics of these populations and implicated their role in regulating the metabolic and immune remodeling of the transplanted liver., Conclusions: In summary, this study delineated a cell atlas (type-proportion-source-time) of the transplanted liver and shed light on the physiological process of graft reconstruction and graft-recipient crosstalk., Competing Interests: Q.J. is a member of PLT Tech Inc. The other authors declare no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: To investigate the impact of orthotopic liver transplantation on serum lipid and growing development in patients with homozygous (HoFH) or compound heterozygotes (cHeFH) familial hypercholesterolemia. Methods: Patients who were treated in Peking Union Medical College Hospital from August 2019 to August 2021, entered the rare disease database and underwent liver transplantation, were included in this single center retrospective cohort study. The height for age Z score (HAZ) and length for age Z score (WAZ) at birth, at the time of transplantation and one year after transplantation were calculated respectively by collecting demographic characteristics, clinical manifestations, echocardiography, lipid-lowering treatment, blood lipid level data and donor characteristics data of liver transplantation. The serum cholesterol level and growing development changes before and after liver transplantation were evaluated. Results: A total of five patients with HoFH or cHeFH, including two females, were included in this study. The median age was 10 years (6-22 years). The median follow up duration was 28 months (24-33 months). All HoFH or cHeFH patients in this study received the maximum daily dosage of the lipid-lowering drug combined with low salt and low-fat diet control treatment for at least 3 months before orthotopic liver transplantation. The average level of total cholesterol (TC) decreased by 27% compared with that before treatment, the level of low-density lipoprotein cholesterol (LDL-C) decreased by 21% after 3 months treatment. There was no intervention of lipid-lowering therapy after operation. One month after liver transplantation, the average levels of TC and LDL-C further decreased rapidly by 68% and 76% respectively. One year after liver transplantation, the level of LDL-C decreased from (17.1±1.6)mmol/L without any intervention before transplantation to (3.0±0.7)mmol/L, and remained stable thereafter. In addition, compared with no intervention before liver transplantation, the serum triglyceride (TG) level decreased after the maximum daily dosage of the lipid-lowering drug and low salt and low-fat diet control for 3 months ((1.88±0.27) mmol/L vs. (1.12±0.55)mmol/L, P =0.031), and the HDL-C level also decreased significantly ((1.95±0.49)mmol/L vs. (0.95±0.30)mmol/L, P =0.006) at the same time period. TG and HDL-C remained stable after liver transplantation during the 24-month follow-up period ( P >0.05). One and two years after liver transplantation, there was no significant difference in height and weight, malnutrition and growth retardation between the patients in this cohort and Chinese children of the same age. Conclusion: Early liver transplantation is a feasible and effective treatment option for HoFH or cHeFH patients with extremely high serum low-density lipoprotein cholesterol levels.

In this study, we explored the effects of cold ischemia on chronic steatosis and lipid signaling in vivo. Sprague Dawley (SD) rat models of chronic steatosis were established. Pathological observations and liver indices were assessed through hematoxylin-eosin (HE)- and Oil Red O staining. Autophagy and metabolism in adipose tissue were analyzed under post-ischemia and hypoxic conditions via western blotting and immunofluorescent analysis. We found that cold ischemia treatment exacerbated hepatic steatosis and reduced lipid phagocytosis. This manifested as a loss of Microtubule-associated protein 1A/1B-light chain 3 (LC3) and Perilipin 2 (PLIN2), and lower levels of autophagy. Cold ischemia also inhibited lipophagy in transplanted rat livers, most notably in moderate-to-severe steatosis models. Ischemia and hypoxia inhibited lipid phagocytosis and increased lipid accumulation. Collectively, these data show that chronic steatosis aggravates cold storage induced acute ischemic injury in rat donor livers through the inhibition of lipophagy. Moderate-to-severe steatosis therefore influences the postoperative recovery of liver transplant recipients, which should be immediately transplanted to reduce the risk of cold ischemia., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

Promoting immune tolerance to transplanted organs can minimize the amount of immunosuppressive drugs that patients need to take, reducing lifetime risks of mortality and morbidity. Regulatory T cells (T regs ) are essential for immune tolerance, and preclinical studies have shown their therapeutic efficacy in inducing transplantation tolerance. Here, we report the results of a phase 1/2 trial (ARTEMIS, NCT02474199) of autologous donor alloantigen-reactive T reg (darT reg ) therapy in individuals 2 to 6 years after receiving a living donor liver transplant. The primary efficacy endpoint was calcineurin inhibitor dose reduction by 75% with stable liver function tests for at least 12 weeks. Among 10 individuals who initiated immunosuppression withdrawal, 1 experienced rejection before planned darT reg infusion, 5 received darT regs , and 4 were not infused because of failure to manufacture the minimal infusible dose of 100 × 10 6 cells. darT reg infusion was not associated with adverse events. Two darT reg -infused participants reached the primary endpoint, but an insufficient number of recipients were treated for assessing the efficacy of darT regs . Mechanistic studies revealed generalized T reg activation, senescence, and selective reduction of donor reactivity after liver transplantation. Overall, the ARTEMIS trial features a design concept for evaluating the efficacy of T reg therapy in transplantation. The mechanistic insight gained from the study may help guide the design of future trials.

Excellent short-term survival after pediatric liver transplantation (LT) has shifted attention toward the optimization of long-term outcomes. Despite considerable progress in imaging and other noninvasive modalities, liver biopsies continue to be required to monitor allograft health and to titrate immunosuppression. However, a standardized approach to the detailed assessment of long-term graft histology is currently lacking. The aim of this study was to formulate a list of histopathological features relevant for the assessment of long-surviving liver allograft health and to develop an approach for assessing the presence and severity of these features in a standardized manner. Whole-slide digital images from 31 biopsies obtained ≥4 years after transplantation to determine eligibility for an immunosuppression withdrawal trial were selected to illustrate a range of typical histopathological findings seen in children with clinically stable grafts, including those associated with alloantibodies. Fifty histological features were independently assessed and, where appropriate, scored semiquantitatively by six pathologists to determine inter- and intraobserver reproducibility of the histopathological features using unweighted and weighted kappa statistics; the latter metric enabled distinction between minor and major disagreements in parameter severity scoring. Weighted interobserver kappa statistics showed a high level of agreement for various parameters of inflammation, interface activity, fibrosis, and microvascular injury. Intraobserver agreement for these features was even more substantial. The results of this study will help to standardize the assessment of biopsies from long-surviving liver allografts, aid the recognition of important histological features, and facilitate international comparisons and clinical trials aiming to improve outcomes for children undergoing LT., (© 2022 American Association for the Study of Liver Diseases.)

Background and Aims: Frailty is a well-established risk factor for poor outcomes in patients with cirrhosis awaiting liver transplantation (LT), but whether it predicts outcomes among those who have undergone LT is unknown., Approach and Results: Adult LT recipients from 8 US centers (2012-2019) were included. Pre-LT frailty was assessed in the ambulatory setting using the Liver Frailty Index (LFI). "Frail" was defined by an optimal cut point of LFI ≥ 4.5. We used the 75th percentile to define "prolonged" post-LT length of stay (LOS; ≥12 days), intensive care unit (ICU) days (≥4 days), and inpatient days within 90 post-LT days (≥17 days). Of 1166 LT recipients, 21% were frail pre-LT. Cumulative incidence of death at 1 and 5 years was 6% and 16% for frail and 4% and 10% for nonfrail patients (overall log-rank p = 0.02). Pre-LT frailty was associated with an unadjusted 62% increased risk of post-LT mortality (95% CI, 1.08-2.44); after adjustment for body mass index, HCC, donor age, and donation after cardiac death status, the HR was 2.13 (95% CI, 1.39-3.26). Patients who were frail versus nonfrail experienced a higher adjusted odds of prolonged LT LOS (OR, 2.00; 95% CI, 1.47-2.73), ICU stay (OR, 1.56; 95% CI, 1.12-2.14), inpatient days within 90 post-LT days (OR, 1.72; 95% CI, 1.25-2.37), and nonhome discharge (OR, 2.50; 95% CI, 1.58-3.97)., Conclusions: Compared with nonfrail patients, frail LT recipients had a higher risk of post-LT death and greater post-LT health care utilization, although overall post-LT survival was acceptable. These data lay the foundation to investigate whether targeting pre-LT frailty will improve post-LT outcomes and reduce resource utilization., (© 2021 American Association for the Study of Liver Diseases.)

Previous single-center, cross-sectional studies have reported a steep increase in the prevalence and severity of fibrosis through 10 to 15 years after pediatric liver transplantation. We report a multicenter study of paired surveillance biopsies in a contemporary cohort. Children who underwent liver transplant when younger than 6 years old and had paired surveillance liver biopsies were enrolled (n = 78, 35% girls, median 1.2 years old at transplant). A central pathologist graded inflammation, assessed rejection activity index, and staged fibrosis in the portal, sinusoidal, and perivenular compartments, allowing for calculation of the Liver Allograft Fibrosis Score (LAFSc). Analysis of variance tested associations between fibrosis progression and clinical parameters. The first biopsy, at a median 8.2 years (interquartile range, 5.9-11.6 years) after transplantation, showed absent to mild fibrosis (LAFSc 0-2) in 29%, moderate (LAFSc 3-5) in 56%, and severe (LAFSc 6-7) in 14% of patients. The second biopsy, at a median 4.7 years (IQR, 4.3-5.1 years) later, showed fibrosis progression (LAFSc increased by ≥3) in 10 (13%) and regression (LAFSc decreased by ≥3) in 4 (5%) patients. After adjusting for baseline LAFSc, younger age at transplant was the only risk factor for fibrosis progression. Although fibrosis prevalence and severity 6 to 12 years after transplant was similar to previous reports, fibrosis trajectory during the next 4 to 5 years was stable. Our data may be reassuring for children with consistently normal liver tests. A comprehensive understanding of factors determining allograft health during the very long term is essential to optimizing allograft and patient health., (© 2022 by the American Association for the Study of Liver Diseases.)

For pediatric liver transplant (LT) recipients, an ideal outcome is to survive and thrive into adulthood. However, outcomes reporting for all LT recipients typically rely on much shorter-term outcomes, 1-5 years post-LT. Using Organ Procurement and Transplantation Network (OPTN) registry data from 1990 to 2018, this analysis seeks to determine if long-term follow-up and outcome data are complete for pediatric LT recipients age 0 to 12 years who survive at least 1 year post-LT without graft loss (n = 9309). Of the 7948 pediatric transplant recipients who did not die or require re-LT, 1 in 6 was reported as lost to follow-up by their transplant center during long-term follow-up. Rates of lost to follow-up were highest in those transplanted between 1990 and 1999 and increased in early adulthood for all recipients. Almost 10% of pediatric LT recipients who remained in follow-up required relisting for LT. 8% of children remaining in follow-up had graft failure. Lost to follow-up may bias estimates of long-term outcomes and risk factors for poor outcomes. For those remaining in follow-up, graft failure and death continue to occur in the decades after LT. Continued proactive monitoring, management, and innovations are needed to truly optimize post-LT survival for all children., (© 2021 The American Society of Transplantation and the American Society of Transplant Surgeons.)

To extend previous molecular analyses of rejection in liver transplant biopsies in the INTERLIVER study (ClinicalTrials.gov #NCT03193151), the present study aimed to define the gene expression selective for parenchymal injury, fibrosis, and steatohepatitis. We analyzed genome-wide microarray measurements from 337 liver transplant biopsies from 13 centers. We examined expression of genes previously annotated as increased in injury and fibrosis using principal component analysis (PCA). PC1 reflected parenchymal injury and related inflammation in the early posttransplant period, slowly regressing over many months. PC2 separated early injury from late fibrosis. Positive PC3 identified a distinct mildly inflamed state correlating with histologic steatohepatitis. Injury PCs correlated with liver function and histologic abnormalities. A classifier trained on histologic steatohepatitis predicted histologic steatohepatitis with cross-validated AUC = 0.83, and was associated with pathways reflecting metabolic abnormalities distinct from fibrosis. PC2 predicted histologic fibrosis (AUC = 0.80), as did a molecular fibrosis classifier (AUC = 0.74). The fibrosis classifier correlated with matrix remodeling pathways with minimal overlap with those selective for steatohepatitis, although some biopsies had both. Genome-wide assessment of liver transplant biopsies can not only detect molecular changes induced by rejection but also those correlating with parenchymal injury, steatohepatitis, and fibrosis, offering potential insights into disease mechanisms for primary diseases., (© 2021 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Background: Deceased donor and recipient predictors of posttransplant steatosis/steatohepatitis and fibrosis are not well known. Our aim was to evaluate the prevalence and assess donor and recipient predictors of steatosis, steatohepatitis, and fibrosis in liver transplantation recipients., Methods: Using the immune tolerance network A-WISH multicenter study (NCT00135694), donor and recipient demographic and clinical features were collected. Liver biopsies were taken from the donor liver at transplant, and from recipients per protocol and for-cause (ie, abnormal transaminases and to rule out rejection) and were interpreted by a central pathologist., Results: One hundred eighty-three paired donor/recipients liver biopsies at the time of transplant and posttransplant follow-up (median time 582 d; average time to last biopsies was 704 d [SD ± 402 d]) were analyzed. Donor steatosis did not influence recipient steatosis or fibrosis. Ten of 183 recipients had steatohepatitis on the last biopsy. Recipient body mass index at the time of liver biopsy was the most influential factor associated with posttransplant steatosis. Both donor and recipient metabolic syndrome features were not associated with graft steatosis. Untreated hepatitis C viral (HCV) infection was the most influential factor associated with the development of allograft fibrosis., Conclusions: In a large experience evaluating paired donor and recipient characteristics, recipient body mass index at the time of liver biopsy was most significantly associated with posttransplant steatosis. Untreated HCV etiology influenced graft fibrosis. Thus relative to untreated HCV, hepatic fibrosis in those with steatosis/steatohepatitis is less common though long-term follow-up is needed to determine the course of posttransplant fibrosis. Emphasis on recipient weight control is essential., Competing Interests: K.R.R. received advisory board from Abbvie, Gilead, Merck, BMS, Spark Therapeutics, Dova, Shionogi, and Mallinckrodt and research grants (paid to the University of Pennsylvania) from Merck, Gilead, Mallinckrodt, BMS, Abbvie, Grifols, Intercept, Conatus, and Exact Sciences. None of these conflict with the current work. S.F. received consulting from BioMarin Pharmaceutical and Research from Novartis. None of these conflict with the current work. The other authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Background & Aims: Management of long-term immunosuppression following liver transplantation (LT) remains empirical. Surveillance liver biopsies in combination with transcriptional profiling could overcome this challenge by identifying recipients with active alloimmune-mediated liver damage despite normal liver tests, but this approach lacks applicability. Our aim was to investigate the utility of non-invasive tools for the stratification of stable long-term survivors of LT, according to their immunological risk and need for immunosuppression., Methods: We conducted a cross-sectional multicentre study of 190 adult LT recipients assessed to determine their eligibility to participate in an immunosuppression withdrawal trial. Patients had stable liver allograft function and had been transplanted for non-autoimmune non-replicative viral liver disease >3 years before inclusion. We performed histological, immunogenetic and serological studies and measured the intrahepatic transcript levels of an 11-gene classifier highly specific for T cell-mediated rejection (TCMR)., Results: In this cohort, 35.8% of patients harboured clinically silent fibro-inflammatory liver lesions (13.7% had mild damage and 22.1% had moderate-to-severe damage). The severity of liver allograft damage was positively associated with TCMR-related transcripts, class II donor-specific antibodies (DSAs), ALT, AST, and liver stiffness measurement (LSM), and negatively correlated with serum creatinine and tacrolimus trough levels. Liver biopsies were stratified according to their TCMR transcript levels using a cut-off derived from biopsies with clinically significant TCMR. Two multivariable prediction models, integrating ALT+LSM or ALT+class II DSAs, had a high discriminative capacity for classifying patients with or without alloimmune damage. The latter model performed well in an independent cohort of 156 liver biopsies obtained from paediatric liver recipients with similar inclusion/exclusion criteria., Conclusion: ALT, class II DSAs and LSM are valuable tools to non-invasively identify stable LT recipients without significant underlying alloimmunity who could benefit from minimisation of immunosuppression., Lay Summary: A large proportion of liver transplant patients with normal liver tests have inflammatory liver lesions, which in 17% of cases are molecularly indistinguishable from those seen at the time of rejection. ALT, class II donor-specific antibodies and liver stiffness are useful in identifying patients with this form of subclinical rejection. We propose these markers as a useful tool to help clinicians determine if the immunosuppression administered is adequate., Competing Interests: Conflict of interest The authors have no conflicts of interest to declare. Please refer to the accompanying ICMJE disclosure forms for further details., (Copyright © 2021. Published by Elsevier B.V.)

Long-term immunosuppression (IS) leads to systemic complications affecting health-related quality of life (HRQOL) in pediatric liver transplantation (LT) recipients. We serially assessed HRQOL using the PedsQL Generic and Multidimensional Fatigue Scales and Family Impact and Transplant Modules as part of a multicenter prospective immunosuppression withdrawal (ISW) trial between 2012 and 2018. Participants received a primary LT ≥4 years before the study and were on stable IS with normal liver tests and without rejection in the prior 2 years. IS was withdrawn in 7 steps over 36 to 48 weeks. HRQOL was assessed at regular intervals. The primary endpoint was change in disease-specific HRQOL measured by the PedsQL Transplant Module. Generic HRQOL was measured by the PedsQL Generic Scale and was compared with an age-matched and sex-matched multicenter cohort. Of the 88 participants, 39 were boys, median age was 11 years (range, 8-13), and time since transplant was 9 years (range, 6-11). For 36 months, disease-specific HRQOL improved for all participants, whereas generic HRQOL was unchanged. Neither generic nor disease-specific HRQOL changed for the 35 participants who developed acute rejection during ISW. In the first use of patient-reported outcome measures during an ISW trial, we found improvements in disease-specific HRQOL in all participants and no lasting detrimental effects in those who experienced rejection., (Copyright © 2020 by the American Association for the Study of Liver Diseases.)

Background and Aims: Tolerance is transplantation's holy grail, as it denotes allograft health without immunosuppression and its toxicities. Our aim was to determine, among stable long-term pediatric liver transplant recipients, the efficacy and safety of immunosuppression withdrawal to identify operational tolerance., Approach and Results: We conducted a multicenter, single-arm trial of immunosuppression withdrawal over 36-48 weeks. Liver tests were monitored biweekly (year 1), monthly (year 2), and bimonthly (years 3-4). For-cause biopsies were done at investigators' discretion but mandated when alanine aminotransferase or gamma glutamyltransferase exceeded 100 U/L. All subjects underwent final liver biopsy at trial end. The primary efficacy endpoint was operational tolerance, defined by strict biochemical and histological criteria 1 year after stopping immunosuppression. Among 88 subjects (median age 11 years; 39 boys; 57 deceased donor grafts), 33 (37.5%; 95% confidence interval [CI] 27.4%, 48.5%) were operationally tolerant, 16 were nontolerant by histology (met biochemical but failed histological criteria), and 39 were nontolerant by rejection. Rejection, predicted by subtle liver inflammation in trial entry biopsies, typically (n = 32) occurred at ≤32% of the trial-entry immunosuppression dose and was treated with corticosteroids (n = 32) and/or tacrolimus (n = 38) with resolution (liver tests within 1.5 times the baseline) for all but 1 subject. No death, graft loss, or chronic, severe, or refractory rejection occurred. Neither fibrosis stage nor the expression level of a rejection gene set increased over 4 years for either tolerant or nontolerant subjects., Conclusions: Immunosuppression withdrawal showed that 37.5% of selected pediatric liver-transplant recipients were operationally tolerant. Allograft histology did not deteriorate for either tolerant or nontolerant subjects. The timing and reversibility of failed withdrawal justifies future trials exploring the efficacy, safety, and potential benefits of immunosuppression minimization., (© 2020 by the American Association for the Study of Liver Diseases.)

Molecular diagnosis of rejection is emerging in kidney, heart, and lung transplant biopsies and could offer insights for liver transplant biopsies. We measured gene expression by microarrays in 235 liver transplant biopsies from 10 centers. Unsupervised archetypal analysis based on expression of previously annotated rejection-related transcripts identified 4 groups: normal "R1 normal " (N = 129), T cell-mediated rejection (TCMR) "R2 TCMR " (N = 37), early injury "R3 injury " (N = 61), and fibrosis "R4 late " (N = 8). Groups differed in median time posttransplant, for example, R3 injury 99 days vs R4 late 3117 days. R2 TCMR biopsies expressed typical TCMR-related transcripts, for example, intense IFNG-induced effects. R3 injury displayed increased expression of parenchymal injury transcripts (eg, hypoxia-inducible factor EGLN1). R4 late biopsies showed immunoglobulin transcripts and injury-related transcripts. R2 TCMR correlated with histologic rejection although with many discrepancies, and R4 late with fibrosis. R2 TCMR , R3 injury , and R4 late correlated with liver function abnormalities. Supervised classifiers trained on histologic rejection showed less agreement with histology than unsupervised R2 TCMR scores. No confirmed cases of clinical antibody-mediated rejection (ABMR) were present in the population, and strategies that previously revealed ABMR in kidney and heart transplants failed to reveal a liver ABMR phenotype. In conclusion, molecular analysis of liver transplant biopsies detects rejection, has the potential to resolve ambiguities, and could assist with immunosuppressive management., (© 2020 The American Society of Transplantation and the American Society of Transplant Surgeons.)

The impact of donor-specific HLA antibody (DSA) following liver transplantation remains controversial. We hypothesized DSA IgG subclass characteristics, compared to total DSA IgG, might correlate with specific histopathological phenotype(s) of subclinical graft injury. We therefore studied 129 stable, arguably "clinically ideal," pediatric liver recipients at the time of a screening biopsy to enter an immunosuppression withdrawal trial. Sixty-five (50%) subjects tested positive for class II DSA. IgG subclass profile was characterized by mean fluorescence intensity (MFI) and normalized subclass composition (>5%). A prominent IgG4 DSA profile was strongly correlated with greater HLA mismatch, a histopathological phenotype characterized by the presence of interface activity (with variable degrees of fibrosis), and a transcriptional profile of attenuated T cell-mediated rejection. Specifically, compared to those without class II DSA, those with IgG4 class II DSA MFI sum >2000 exhibited an odds ratio (OR) of 20.79 (95% confidence interval [CI] 4.38-98.69) and IgG4 subclass composition >5% exhibited an OR of 8.99 (95% CI 2.70-29.9). Our data suggest that IgG4 DSA may serve as a useful biomarker to identify, among clinically and biochemically stable liver transplant recipients, a subset with histological and transcriptional features indicative of an active, suboptimally controlled alloimmune response., (© 2019 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Objectives: In this study, we aimed to investigate the pathologic and ultrastructural changes in transplanted mouse livers after different durations of cold storage by testing indicators of liver function and energy metabolism. We aimed to describe the effects of cold storage on liver function and the mechanisms of cold storage damage., Materials and Methods: We randomly placed 8-weekold male C57BL/6 mice into the following 4 groups to establish a cold-preserved mouse model of liver transplant: a normal control group and 3 cold storage groups, in which livers were stored for 4, 12, and 24 hours. Hepatic morphology, ultrastructural changes, and glycogenolysis were observed by hematoxylin and eosin staining, periodic acid-Schiff staining, and transmission electron microscopy. After different durations of cold storage, livers were reperfused with 4°C University of Wisconsin solution to obtain perfusion fluid, and alanine and aspartate aminotransferase levels were measured. Glycogen synthase, hypoxia-inducible factor-1α, Krüppel-like factor 2, and endothelial nitric oxide synthase mRNA expression levels in liver tissues were detected by real-time polymerase chain reaction, and aquaporin 8 protein expression levels in liver tissues were detected by Western blot., Results: Hematoxylin and eosin staining and electron microscopy ofliver showed signs ofinjury after 12 hours of cold storage, which included mainly cytoplasmic edema characterized by loose liver cell arrangement, increased hepatic sinus fissure, mitochondrial swelling, and nuclear pyknosis. Periodic acid-Schiff staining showed that glycogen content was significantly reduced, with glycogen synthase levels also reduced. Alanine aminotransferase and aspartate aminotransferase levels gradually increasedwith cold storage. Glycogen synthase, Krüppel-like factor 2, endothelial nitric oxide synthase, and aquaporin 8 expression levels also gradually increased in liver tissue. These levels gradually decreased, but hypoxia-inducible factor-1α increased., Conclusions: Mouse livers showed progressive damage to structure and function during cold storage, with mitochondrial damage perhaps showing the earliest damage.

Although liver biopsy is the gold standard for assessing allograft health, its attendant risk has deterred its use in routine monitoring of stable liver transplant recipients during long-term follow-up. We utilized prospectively collected data on adverse events from 2 clinical trials of immunosuppression withdrawal to quantify the risk of liver biopsy in pediatric liver transplant recipients. The trials included 451 liver biopsies in 179 children. No biopsies led to bleeding requiring transfusion or intervention, suggesting a clinically significant bleeding risk of <0.8%. Complications were reported in 5.5% of biopsies (95% CI 3.6%-8.1%): 5.8% (21/363) of protocol biopsies and 4.5% (4/88) of for-cause biopsies (P = .80). Mild complications occurred in 1.8% of biopsies, moderate in 1.8%, and severe in 2.0%. The majority of complications (89%) resolved within 1 week. Six of 9 (67%) severe complications were related to biliary issues; 5 were episodes of cholangitis. Biopsy-related cholangitis occurred only in children with underlying biliary strictures. Overall, biopsy-related complications were infrequent and resolved quickly. Severe complications were rare, with occult biliary stricture as the dominant driver. Our study provides evidence for clinicians who are considering the risk vs benefit of surveillance liver biopsies in pediatric liver transplant recipients., (© 2019 The American Society of Transplantation and the American Society of Transplant Surgeons.)

The Immune Tolerance Network ITN030ST A-WISH assessed immunosuppression withdrawal in liver transplant recipients with hepatitis C or nonimmune nonviral liver disease. Of 275 recipients enrolled before transplantation, 95 were randomly assigned 4:1 to withdrawal (n = 77) or maintenance (n = 18) 1- to 2-years posttransplant. Randomization eligibility criteria included stable immunosuppression monotherapy; adequate liver and kidney function; ≤Stage 2 Ishak fibrosis; and absence of rejection on biopsy. Immunosuppression withdrawal followed an 8-step reduction algorithm with ≥8 weeks per level. Fifty-two of 77 subjects (67.5%) reduced to ≤50% of baseline dose, and 10 of 77 (13.0%) discontinued all immunosuppression for ≥1 year. Acute rejection and/or abnormal liver tests were treated with increased immunosuppression; 5 of 32 rejection episodes required a methylprednisolone bolus. The composite end point (death or graft loss; grade 4 secondary malignancy or opportunistic infection; Ishak stage ≥3; or >25% decrease in glomerular filtration rate within 24 months of randomization) occurred in 12 of 66 (18%) and 4 of 13 (31%) subjects in the withdrawal and maintenance groups. Early immunosuppression minimization is feasible in selected liver recipients, while complete withdrawal is successful in only a small proportion. The composite end point comparison was inconclusive for noninferiority of the withdrawal to the maintenance group., (© 2018 The American Society of Transplantation and the American Society of Transplant Surgeons.)

The development of human leukocyte antigen (HLA) donor-specific antibody/antibodies (DSA) is not well described in liver transplant (LT) patients undergoing immunosuppression (IS) withdrawal protocols despite the allograft risk associated with de novo DSA (dnDSA). We analyzed the development of dnDSA in 69 LT patients who received calcineurin inhibitor monotherapy and were enrolled in the ITN030ST study. Of these 69 patients, 40 stable patients were randomized to IS maintenance (n = 9) or IS minimization (n = 31). Nine of the 31 IS minimization patients achieved complete withdrawal and were free of IS. Among patients who achieved stable IS monotherapy 1 year after transplantation, the prevalence of dnDSA was 18.8%. Acute rejections and the biopsy-proven findings disqualifying patients from IS withdrawal attempt were factors associated with dnDSA development (P = 0.011 and P = 0.041, respectively). Among randomized patients, dnDSA prevalence was 51.7% after IS minimization and 66.7% in IS-free patients. dnDSA prevalence in patients on IS maintenance was 44.4%. dnDSA development during IS minimization was a risk factor for acute rejection (P = 0.015). The majority of dnDSA were against HLA-DQ antigens (78.7%). Conclusion. During the first year following transplantation, acute rejections increase the risk of developing dnDSA, so dnDSA positivity should be considered for IS withdrawal eligibility; during IS minimization, dnDSA development was associated with acute rejection, which prevented further IS withdrawal attempts., (© 2018 by the American Association for the Study of Liver Diseases.)

Background & Aims: A substantial proportion of pediatric liver transplant recipients develop subclinical chronic allograft injury. We studied whether there are distinct patterns of injury based on histopathologic features and identified associated immunologic profiles., Methods: We conducted a cross-sectional study of 157 stable, long-term pediatric recipients of transplanted livers (70 boys; > 6 years old at time of transplantation; mean, 8.9 ± 3.46 years after liver transplantation) who underwent liver biopsy analysis from August 13, 2012, through May 1, 2014. Participants had received livers from a living or deceased donor and had consistently normal results from liver tests. Liver biopsy specimens were scored by a central pathologist; an unsupervised hierarchical cluster analysis of histologic features was used to sort biopsy samples into 3 clusters. We conducted transcriptional and cytometric analyses of liver tissue samples and performed a systems biology analysis that incorporated clinical, serologic, histologic, and transcriptional data., Results: The mean level of alanine aminotransferase in participants was 27.6 ± 14.57 U/L, and the mean level of γ-glutamyl transferase was 17.4 ± 7.93 U/L. Cluster 1 was characterized by interface activity (n = 34), cluster 2 was characterized by periportal or perivenular fibrosis without interface activity (n = 45), and cluster 3 had neither feature (n = 78). We identified a module of genes whose expression correlated with levels of alanine aminotransferase, class II donor-specific antibody, portal inflammation, interface activity, perivenular inflammation, portal and perivenular fibrosis, and cluster assignment. The module was enriched in genes that regulate T-cell-mediated rejection (TCMR) of liver and other transplanted organs. Functional pathway analysis showed overrepresentation of TCMR gene sets for cluster 1 but not clusters 2 or 3., Conclusion: In an analysis of biopsies from an apparently homogeneous group of stable, long-term pediatric liver transplant recipients with consistently normal liver test results, we found evidence of chronic graft injury (inflammation and/or fibrosis). Biopsy samples with interface activity had a gene expression pattern associated with TCMR., (Copyright © 2018 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Frailty is prevalent in liver transplant candidates, but little is known of what happens to frailty after liver transplantation. We analyzed data for 214 adult liver transplant recipients who had ≥1 frailty assessment using the Liver Frailty Index (LFI) at 3- (n = 178), 6- (n = 139), or 12- (n = 107) months posttransplant (higher values=more frail). "Frail" and "robust" were defined as LFI ≥4.5 and <3.2. Median pre-liver transplant LFI was 3.7, and was worse at 3 months (3.9; P = .02), similar at 6 months (3.7; P = .07), and improved at 12 months (3.4; P < .001). The percentage who were robust pre- and 3-, 6-, and 12-months posttransplant were 25%, 14%, 28%, and 37%; the percentage frail were 21%, 21%, 10%, and 7%. In univariable analysis, each 0.1 pretransplant LFI point more frail was associated with a decreased odds of being robust at 3- (odds ratio [OR] 0.75), 6- (OR 0.77), and 12-months (OR 0.90) posttransplant (P ≤ .001), which did not change substantially with multivariable adjustment. In conclusion, frailty worsens 3 months posttransplant and improves modestly by 12 months, but fewer than 2 of 5 patients achieve robustness. Pretransplant LFI was a potent predictor of posttransplant robustness. Aggressive interventions aimed at preventing frailty pretransplant are urgently needed to maximize physical health after liver transplantation., (© 2018 The American Society of Transplantation and the American Society of Transplant Surgeons.)

While advances in immunosuppressive therapy have lowered the rate of acute rejection following liver transplantation, the consequence has been an increase in morbidity and mortality related to the lifelong need for maintenance immunosuppression. These complications include an increased risk of malignancy, infection, metabolic disorders, and chronic kidney disease, as well as high health care costs associated with these therapies and the required drug monitoring. Given these issues, most clinicians attempt trial and error dose minimization with variable success rates, and there has been significant interest in full drug withdrawal in select patients through research protocols. These strategies would be more successful if immunomodulatory therapies early after transplantation could be developed and if immune activation biomarkers guiding drug tapering were available to personalize these approaches. This review will review the mechanisms of liver transplant tolerance and potential strategies to achieve immunosuppression withdrawal., (Copyright © 2017. Published by Elsevier Inc.)

Impeccable management of immunosuppression is required to ensure the best longterm outcomes for liver transplant recipients. This is particularly challenging for children who arguably need 8 decades of graft and patient survival. Too little risks chronic, often subclinical allo-immune injury while too much risks insidious and cumulative toxicities. Historically, immunosuppression minimization or withdrawal has been a strategy to optimize the longevity of liver transplant recipients. The literature is sprinkled with single-center reports of operationally tolerant patients - those with apparently normal liver function and liver tests. However, without biopsy evidence of immunological quiescence, confidence in the phenotypic assignment of tolerance is shaky. More recently, multicenter trials of immunosuppression withdrawal for highly selected, stable, longterm adult and pediatric liver recipients have shown tolerance rates, based on both biochemical and histological assessment, of 40% and 60%, respectively. Extended biochemical and histologic follow-up of children over 8 years, equivalent to 7+ years off of drug, suggests that operational tolerance is robust. Therefore, clearly, immunosuppression can be completely and safety withdrawn from highly-selected subsets of adults and children. However, these trials have also confirmed that clinically ideal recipients - those eligible for immunosuppression withdrawal trial - can harbor significant and worrisome inflammation and/or fibrosis. Although the etiology and prognosis of these findings remain unknown, it is reasonable to surmise that they may reflect an anti-donor immune response that is insufficiently controlled. To achieve the outcomes that we are seeking and that our patients are demanding, we desperately need noninvasive but accurate biomarkers that identify whether immunosuppression is neither too much nor too little but "just right." Until these are available, liver histology remains the gold standard to assess allograft health and guide immunosuppression management. Liver Transplantation 23 1601-1614 2017 AASLD., (© 2017 by the American Association for the Study of Liver Diseases.)

As pediatric liver transplantation comes of age, experts gathered to discuss current paradigms and define gaps in knowledge warranting research to further improve patient and graft outcomes. Identified areas ripe for collaborative research include understanding the molecular and cellular mechanisms of tolerance and the role of donor-specific antibodies, considering ways to expand donor pool, minimizing long-term side effects of immunosuppression, and fine-tuning surgical techniques to minimize biliary and vascular complications.

Pediatric liver transplant recipients arguably have the most to gain and the most to lose from discontinuing immunosuppression (IS). Whereas IS undoubtedly exerts a cumulative toll, there is concern that insufficient or no IS may contribute to allograft deterioration. Twelve pediatric recipients of parental living donor liver grafts, identified as operationally tolerant through complete IS withdrawal (WISP-R; NCT00320606), were followed for a total of 5 years (1 year of IS withdrawal and 4 years off IS) with serial liver tests and autoantibody and alloantibody assessments. Liver biopsies were performed 2 and 4 years off IS, and, at these time points, immunoglobulin G (IgG) subclass and C1q binding activity for donor-specific antibodies (DSAs) were determined. There were no cases of chronic rejection, graft loss, or death. Allografts did not exhibit progressive increase in inflammation or fibrosis. Smooth-muscle actin expression by stellate cells and CD34 expression by liver sinusoidal endothelial cells remained stable, consistent with the absence of progressive graft injury. Three subjects never exhibited DSA. However, 3 subjects showed intermittent de novo class I DSA, 4 subjects showed persistent de novo class II DSA, and 5 subjects showed persistent preexisting class II DSA. Class II DSA was predominantly against donor DQ antigens, often of high mean fluorescence intensity, rarely of the IgG3 subclass, and often capable of binding C1q., Conclusion: Operationally tolerant pediatric liver transplant recipients maintain generally stable allograft histology in spite of apparently active humoral allo-immune responses. The absence of increased inflammation or progressive fibrosis suggests that a subset of liver allografts seem resistant to the chronic injury that is characteristic of antibody-mediated damage. (Hepatology 2017;65:647-660)., (© 2016 by the American Association for the Study of Liver Diseases.)

The Banff Working Group on Liver Allograft Pathology reviewed and discussed literature evidence regarding antibody-mediated liver allograft rejection at the 11th (Paris, France, June 5-10, 2011), 12th (Comandatuba, Brazil, August 19-23, 2013), and 13th (Vancouver, British Columbia, Canada, October 5-10, 2015) meetings of the Banff Conference on Allograft Pathology. Discussion continued online. The primary goal was to introduce guidelines and consensus criteria for the diagnosis of liver allograft antibody-mediated rejection and provide a comprehensive update of all Banff Schema recommendations. Included are new recommendations for complement component 4d tissue staining and interpretation, staging liver allograft fibrosis, and findings related to immunosuppression minimization. In an effort to create a single reference document, previous unchanged criteria are also included., (© Copyright 2016 The American Society of Transplantation and the American Society of Transplant Surgeons.)

Background: Sarcopenia and functional impairment are common and lethal extrahepatic manifestations of cirrhosis. We aimed to determine the association between computed tomography (CT)-based measures of muscle mass and quality (sarcopenia) and performance-based measures of muscle function., Methods: Adults listed for liver transplant underwent testing of muscle function (grip strength, Short Physical Performance Battery [SPPB]) within 3 months of abdominal CT. Muscle mass (cm/m) = total cross-sectional area of psoas, paraspinal, and abdominal wall muscles at L3 on CT, normalized for height. Muscle quality = mean Hounsfield units for total skeletal muscle area at L3., Results: Among 292 candidates, median grip strength was 31 kg, SPPB score was 11, muscle mass was 49 cm/m, and muscle quality was 35 Hounsfield units. Grip strength weakly correlated with muscle mass (ρ = 0.26, P < 0.001) and quality (ρ = 0.27, P < 0.001) in men, and muscle quality (ρ = 0.23, P = 0.02), but not muscle mass, in women. Short Physical Performance Battery correlated weakly with muscle quality in men (ρ = 0.38, P < 0.001) and women (ρ = 0.25, P = 0.02), however, did not correlate with muscle mass in men or women. After adjustment for sex, model for end-stage liver disease (MELD)-Na, hepatocellular carcinoma, and body mass index, grip strength (hazard ratio [HR], 0.74; 95% confidence interval [95% CI], 0.59-0.92; P = 0.008), SPPB (HR, 0.89; 95% CI, 0.82-0.97; P = 0.01), and muscle quality (HR, 0.77; 95% CI, 0.63-0.95; P = 0.02) were associated with waitlist mortality, but muscle mass was not (HR, 0.91; 95% CI, 0.75-1.11; P = 0.35)., Conclusions: Performance-based tests of muscle function are only modestly associated with CT-based muscle measures. Given that they predict waitlist mortality and can be conducted quickly and economically, tests of muscle function may have greater clinical utility than CT-based measures of sarcopenia.

Background and Aims: The beneficial effect of one graft on another has been reported in combined transplantation but the associated mechanisms and biological influence of each graft have not yet been established., Methods: In multiple analyses, we explored the PBMC phenotype and signature of 45 immune-related messenger RNAs and 754 microRNAs from a total of 235 patients, including combined liver-kidney transplant recipients (CLK), patients with a liver (L-STA) or kidney (K-STA) graft only under classical immunosuppression and patients with tolerated liver (L-TOL) or kidney grafts (K-TOL)., Results: CLK show an intermediary phenotype with a higher percentage of peripheral CD19(+) CD24(+) CD38(Low) memory B cells and Helios(+) Treg cells, two features associated with tolerance profiles, compared to L-STA and K-STA (P < 0.05, P < 0.01). Very few miRNA were significantly differentially expressed in CLK vs. K-STA and even fewer when compared to L-STA (35 and 8, P < 0.05). Finally, CLK are predicted to share common miRNA targets with K-TOL and even more with L-TOL (344 and 411, P = 0.005). Altogether CLK display an intermediary phenotype and gene profile, which is closer to that of liver transplant patients, with possible similarities with the profiles of tolerant patients., Conclusion: These data suggest that CLK patients show the immunological influence of both allografts with liver having a greater influence., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Purpose of Review: Transformative medical and surgical advances have remarkably improved short-term survival after liver transplantation. There is, however, pervasive concern that the cumulative toxicities of modern immunosuppression regimens severely compromise both quality and quantity of life for liver transplant recipients. The inherently tolerogenic nature of the liver offers the tantalizing opportunity to change the current paradigm of nonspecific and lifelong immunosuppression. Safe minimization or discontinuation of immunosuppression without damage to the liver allograft is an attractive strategy to improve long-term survival after liver transplantation., Recent Findings: Recent prospective, multicenter clinical trials have demonstrated that immunosuppression can be safely withdrawn from selected liver transplant recipients with preservation of allograft histology. These successes have spurred multiple avenues of investigation to identify peripheral blood and/or tissue biomarkers and delineate mechanisms of tolerance. Concomitant advances in the ability to expand regulatory T cells in the laboratory have spawned clinical trials to facilitate immunosuppression minimization and/or discontinuation., Summary: This review will delineate the unique liver immunobiology that has driven the recent clinical trials to unmask spontaneous tolerance or induce tolerance for liver transplant recipients. The emerging results of these trials over the next 5 years hold promise to reduce the burden of lifelong immunosuppression and thereby optimize the long-term health of liver transplant recipients.

The emerging epidemic of older patients with cirrhosis has led to a sharp increase in the number of ≥65 year olds considering liver transplantation (LT). However, clinicians lack objective measures to risk stratify older patients. We aimed to determine whether the short physical performance battery (SPPB), a well-validated geriatric measure of physical function, has greater prognostic value in older versus younger LT candidates. Adult outpatients listed for LT with laboratory Model for End-Stage Liver Disease score ≥ 12 underwent physical function testing using the SPPB, consisting of gait speed, chair stands, and balance. Patients were categorized by age ("younger," < 65 years; "older," ≥ 65 years) and SPPB ("impaired," ≤ 9; "robust," > 9). Competing risks models associated age and SPPB with wait-list death/delisting. Of 463 LT candidates, 21% were ≥ 65 years and 18% died or were delisted. Older patients had slower gait (1.1 versus 1.3 m/seconds; P < 0.001), a trend of slower chair stands (12.8 versus 11.8 seconds; P = 0.06), and a smaller proportion able to complete all balance tests (65% versus 78%; P = 0.01); SPPB was lower in older versus younger patients (10 versus 11; P = 0.01). When compared to younger robust patients as a reference group, younger impaired patients (hazard ratio [HR], 1.77; P = 0.03) and older impaired patients (HR, 2.70; P = 0.003) had significantly higher risk of wait-list mortality, but there was no difference in risk for older robust patients (HR 1.38; P = 0.35) [test of equality, P = 0.01]. After adjustment for Model for End-Stage Liver Disease-sodium (MELD-Na) score, only older impaired patients had an increased risk of wait-list mortality compared to younger robust patients (HR, 2.36; P = 0.01; test of equality P = 0.05). In conclusion, functional impairment, as assessed by the SPPB, predicts death/delisting for LT candidates ≥65 years independent of MELD-Na. Further research into activity-based interventions to reduce adverse transplant outcomes in this population is warranted., (© 2015 American Association for the Study of Liver Diseases.)

Background & Aims: The US liver allocation system effectively prioritizes most liver transplant candidates by disease severity as assessed by the Model for End-Stage Liver Disease (MELD) score. Yet, one in five dies on the wait-list. We aimed to determine whether clinician assessments of health status could identify this subgroup of patients at higher risk for wait-list mortality., Methods: From 2012-2013, clinicians of all adult liver transplant candidates with laboratory MELD≥12 were asked at the clinic visit: 'How would you rate your patient's overall health today (0 = excellent, 5 = very poor)?' The odds of death/delisting for being too sick for the transplant by clinician-assessment score ≥3 vs. <3 were assessed by logistic regression., Results: Three hundred and forty-seven liver transplant candidates (36% female) had a mean follow-up of 13 months. Men differed from women by disease aetiology (<0.01) but were similar in age and markers of liver disease severity (P > 0.05). Mean clinician assessment differed between men and women (2.3 vs. 2.6; P = 0.02). The association between clinician-assessment and MELD was ρ = 0.28 (P < 0.01). 53/347 (15%) died/were delisted. In univariable analysis, a clinician-assessment score ≥ 3 was associated with increased odds of death/delisting (2.57; 95% CI 1.42-4.66). After adjustment for MELD and age, a clinician-assessment score ≥ 3 was associated with 2.25 (95% CI 1.22-4.15) times the odds of death/delisting compared to a clinician-assessment score < 3., Conclusions: A standardized clinician assessment of health status can identify liver transplant candidates at high risk for wait-list mortality independent of MELD score. Objectifying this 'eyeball test' may inform interventions targeted at this vulnerable subgroup to optimize wait-list outcomes., (© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)