Banff 2022 Liver Group Meeting report: Monitoring long-term allograft health

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.

A modified Hospital Frailty Risk Score for patients with cirrhosis undergoing abdominal operations

BACKGROUND AND AIMS

Existing tools for perioperative risk stratification in patients with cirrhosis do not incorporate measures of comorbidity. The Hospital Frailty Risk Score (HFRS) is a widely used measure of comorbidity burden in administrative dataset analyses. However, it is not specific to patients with cirrhosis, and application of this index is limited by its complexity.

APPROACH AND RESULTS

Adult patients with cirrhosis who underwent nontransplant abdominal operations were identified from the National Inpatient Sample, 2016-2018. Adjusted associations between HFRS and in-hospital mortality and length of stay were computed with logistic and Poisson regression. Lasso regularization was used to identify the components of the HFRS most predictive of mortality and develop a simplified index, the cirrhosis-HFRS. Of 10,714 patients with cirrhosis, the majority were male, the median age was 62 years, and 32% of operations were performed electively. HFRS was associated with an increased risk of both in-hospital mortality (OR=6.42; 95% CI: 4.93, 8.36) and length of stay (incidence rate ratio [IRR]=1.79; 95% CI: 1.72, 1.88), with adjustment. Using lasso, we found that a subset of 12 of the 109 ICD-10 codes within the HFRS resulted in superior prediction of mortality in this patient population (AUC = 0.89 vs. 0.79, p < 0.001).

CONCLUSIONS

While the 109-component HFRS was associated with adverse surgical outcomes, 12 components accounted for much of the association between the HFRS and mortality. We developed the cirrhosis-HFRS, a tool that demonstrates superior predictive accuracy for in-hospital mortality and more precisely reflects the specific comorbidity pattern of hospitalized patients with cirrhosis undergoing general surgery procedures.

Transforming the Future of Surgeon-Scientists

OBJECTIVE

To create a blueprint for surgical department leaders, academic institutions, and funding agencies to optimally support surgeon-scientists.

BACKGROUND

Scientific contributions by surgeons have been transformative across many medical disciplines. Surgeon-scientists provide a distinct approach and mindset toward key scientific questions. However, lack of institutional support, pressure for increased clinical productivity, and growing administrative burden are major challenges for the surgeon-scientist, as is the time-consuming nature of surgical training and practice.

METHODS

An American Surgical Association Research Sustainability Task Force was created to outline a blueprint for sustainable science in surgery. Leaders from top NIH-sponsored departments of surgery engaged in video and in-person meetings between January and April 2023. A strength, weakness, opportunities, threats analysis was performed, and workgroups focused on the roles of surgeons, the department and institutions, and funding agencies.

RESULTS

Taskforce recommendations: (1) SURGEONS: Growth mindset : identifying research focus, long-term planning, patience/tenacity, team science, collaborations with disparate experts; Skill set : align skills and research, fill critical skill gaps, develop team leadership skills; DEPARTMENT OF SURGERY (DOS): (2) MENTORSHIP: Chair : mentor-mentee matching/regular meetings/accountability, review of junior faculty progress, mentorship training requirement, recognition of mentorship (eg, relative value unit equivalent, awards; Mentor: dedicated time, relevant scientific expertise, extramural funding, experience and/or trained as mentor, trusted advisor; Mentee : enthusiastic/eager, proactive, open to feedback, clear about goals; (3) FINANCIAL SUSTAINABILITY: diversification of research portfolio, identification of matching funding sources, departmental resource awards (eg, T-/P-grants), leveraging of institutional resources, negotiation of formalized/formulaic funds flow investment from academic medical center toward science, philanthropy; (4) STRUCTURAL/STRATEGIC SUPPORT: Structural: grants administrative support, biostats/bioinformatics support, clinical trial and research support, regulatory support, shared departmental laboratory space/equipment; Strategic: hiring diverse surgeon-scientist/scientists faculty across DOS, strategic faculty retention/ recruitment, philanthropy, career development support, progress tracking, grant writing support, DOS-wide research meetings, regular DOS strategic research planning; (5) COMMUNITY AND CULTURE: Community: right mix of faculty, connection surgeon with broad scientific community; Culture: building research infrastructure, financial support for research, projecting importance of research (awards, grand rounds, shoutouts); (6) THE ROLE OF INSTITUTIONS: Foundation: research space co-location, flexible start-up packages, courses/mock study section, awards, diverse institutional mentorship teams; Nurture: institutional infrastructure, funding (eg, endowed chairs), promotion friendly toward surgeon-scientists, surgeon-scientists in institutional leadership positions; Expectations: RVU target relief, salary gap funding, competitive starting salaries, longitudinal salary strategy; (7) THE ROLE OF FUNDING AGENCIES: change surgeon research training paradigm, offer alternate awards to K-awards, increasing salary cap to reflect market reality, time extension for surgeon early-stage investigator status, surgeon representation on study section, focused award strategies for professional societies/foundations.

CONCLUSIONS

Authentic recommitment from surgeon leaders with intentional and ambitious actions from institutions, corporations, funders, and society is essential in order to reap the essential benefits of surgeon-scientists toward advancements of science.

Advancing mouse models for transplantation research

Mouse models have been instrumental in understanding mechanisms of transplant rejection and tolerance, but cross-study reproducibility and translation of experimental findings into effective clinical therapies are issues of concern. The Mouse Models in Transplantation symposium gathered scientists and physician-scientists involved in basic and clinical research in transplantation to discuss the strengths and limitations of mouse transplant models and strategies to enhance their utility. Participants recognized that increased procedure standardization, including the use of prespecified, defined endpoints, and statistical power analyses, would benefit the field. They also discussed the generation of new models that incorporate environmental and genetic variables affecting clinical outcomes as potentially important. If implemented, these strategies are expected to improve the reproducibility of mouse studies and increase their translation to clinical trials and, ideally, new Food and Drug Administration-approved drugs.

[Epidemiological characteristics of a local cluster epidemic caused by the BA.2 evolutionary branch of Omicron variant]

Descriptive epidemiological methods were used to analyze the epidemiological characteristics of the local cluster of COVID-19 in the logistic park of Yuhang District in Hangzhou in March 2022. The cluster epidemic was detected by a case who actively visited the fever clinic. The epidemic lasted for 8 days, and a total of 58 cases (53 workers, 2 students, 1 farmer, 1 teacher and 1 unemployed) were found, including 40 males and 18 females. The age was (33.29±12.22) years. There cases were mainly in Yuhang District (48 cases, 82.77%) and Shangcheng District (7 cases, 12.07%) of Hangzhou. The real-time regeneration number peaked at 2.31 on March 10th and decreased to 0.37 on March 15th. The sequencing result of the indicated case was 100% homologous with the sequence uploaded from South Korea on March 4th, 2022.

Time since liver transplant and immunosuppression withdrawal outcomes: Systematic review and individual patient data meta-analysis

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.

[Clinical characteristics of epileptic seizure in neurofibromatosis type 1 in 15 cases]

Objective: To summarize the clinical characteristics of epileptic seizure associated with neurofibromatosis type 1 (NF1). Methods: From January 2017 to July 2023 at Children's Hospital Capital Institute of Pediatrics, medical records of patients with both NF1 and epileptic seizure were reviewed in this case series study. The clinical characteristics, treatment and prognosis were analyzed retrospectively. Results: A total of 15 patients(12 boys and 3 girls) were collected. Café-au-lait macules were observed in all 15 patients. There were 6 patients with neurodevelopmental disorders and the main manifestations were intellectual disability or developmental delay. The age at the first epileptic seizure was 2.5 (1.2, 5.5) years. There were various seizure types, including generalized tonic-clonic seizures in 8 patients, focal motor seizures in 6 patients, epileptic spasm in 4 patients, tonic seizures in 1 patient, absence in 1 patient, generalized myoclonic seizure in 1 patient and focal to bilateral tonic-clonic seizure in 1 patient. Among 14 patients whose brain magnetic resonance imaging results were available, there were abnormal signals in corpus callosum, basal ganglia, thalamus or cerebellum in 6 patients, dilated ventricles of different degrees in 3 patients, blurred gray and white matter boundary in 2 patients, agenesis of corpus callosum in 1 patient and no obvious abnormalities in the other patients. Among 13 epilepsy patients, 8 were seizure-free with 1 or 2 antiseizure medications(ASM), 1 with drug resistant epilepsy was seizure-free after left temporal lobectomy, and the other 4 patients who have received 2 to 9 ASM had persistent seizures. One patient with complex febrile convulsion achieved seizure freedom after oral administration of diazepam on demand. One patient had only 1 unprovoked epileptic seizure and did not have another seizure without taking any ASM. Conclusions: The first epileptic seizure in NF1 patients usually occurs in infancy and early childhood, with the main seizure type of generalized tonic-clonic seizure and focal motor seizure. Some patients have intellectual disability or developmental delay. Most epilepsy patients achieve seizure freedom with ASM.

Normothermic Machine Perfusion of Donor Livers for Transplantation in the United States: A Randomized Controlled Trial

OBJECTIVE

To compare conventional low-temperature storage of transplant donor livers [static cold storage (SCS)] with storage of the organs at physiological body temperature [normothermic machine perfusion (NMP)].

BACKGROUND

The high success rate of liver transplantation is constrained by the shortage of transplantable organs (eg, waiting list mortality >20% in many centers). NMP maintains the liver in a functioning state to improve preservation quality and enable testing of the organ before transplantation. This is of greatest potential value with organs from brain-dead donor organs (DBD) with risk factors (age and comorbidities), and those from donors declared dead by cardiovascular criteria (donation after circulatory death).

METHODS

Three hundred eighty-three donor organs were randomized by 15 US liver transplant centers to undergo NMP (n = 192) or SCS (n = 191). Two hundred sixty-six donor livers proceeded to transplantation (NMP: n = 136; SCS: n = 130). The primary endpoint of the study was "early allograft dysfunction" (EAD), a marker of early posttransplant liver injury and function.

RESULTS

The difference in the incidence of EAD did not achieve significance, with 20.6% (NMP) versus 23.7% (SCS). Using exploratory, "as-treated" rather than "intent-to-treat," subgroup analyses, there was a greater effect size in donation after circulatory death donor livers (22.8% NMP vs 44.6% SCS) and in organs in the highest risk quartile by donor risk (19.2% NMP vs 33.3% SCS). The incidence of acute cardiovascular decompensation at organ reperfusion, "postreperfusion syndrome," as a secondary outcome was reduced in the NMP arm (5.9% vs 14.6%).

CONCLUSIONS

NMP did not lower EAD, perhaps related to the inclusion of lower-risk liver donors, as higher-risk donor livers seemed to benefit more. The technology is safe in standard organ recovery and seems to have the greatest benefit for marginal donors.

Real-world implementation of normothermic machine perfusion: A detailed analysis of intraoperative and early postoperative impact

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.

DCD liver transplant in patients with a MELD over 35

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.

Mapping children by ALT 4-5 years after liver transplant: Potential individual and population applications

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.

[A case of combined oxidative phosphorylation deficiency 32 caused by MRPS34 gene variation and literature review]

Objective: To investigate the clinical features and genetic features of combined oxidative phosphorylation deficiency 32 (COXPD32) caused by MRPS34 gene variation. Methods: The clinical data and genetic test of a child with COXPD32 hospitalized in the Department of Neurology, Children's Hospital, Capital Institute of Pediatrics in March 2021 were extracted and analyzed. A literature search was implemented using Wanfang, China biology medicine disc, China national knowledge infrastructure, ClinVar, human gene mutation database (HGMD) and Pubmed databases with the key words "MRPS34" "MRPS34 gene" and "combined oxidative phosphorylation deficiency 32" (up to February 2023). Clinical and genetic features of COXPD32 were summarized. Results: A boy aged 1 year and 9 months was admitted due to developmental delay. He showed mental and motor retardation, and was below the 3^rd percentile for height, weight, and head circumference of children of the same age and gender. He had poor eye contact, esotropia, flat nasal bridge, limbs hypotonia, holding instability and tremors. In addition, Grade Ⅲ/6 systolic murmur were heard at left sternal border. Arterial blood gases suggested that severe metabolic acidosis with lactic acidosis. Brain magnetic resonance imaging (MRI) showed multiple symmetrical abnormal signals in the bilateral thalamus, midbrain, pons and medulla oblongata. Echocardiography showed atrial septal defect. Genetic testing identified the patient as a compound heterozygous variation of MRPS34 gene, c.580C>T (p.Gln194Ter) and c.94C>T (p.Gln32Ter), with c.580C>T being the first report and a diagnosis of COXPD32. His parents carried a heterozygous variant, respectively. The child improved after treatment with energy support, acidosis correction, and "cocktail" therapy (vitaminB₁, vitaminB₂, vitaminB₆, vitaminC and coenzyme Q10). A total of 8 cases with COXPD32 were collected through 2 English literature reviews and this study. Among the 8 patients, 7 cases had onset during infancy and 1 was unknown, all had developmental delay or regression, 7 cases had feeding difficulty or dysphagia, followed by dystonia, lactic acidosis, ocular symptoms, microcephaly, constipation and dysmorphic facies(mild coarsening of facial features, small forehead, anterior hairline extending onto forehead,high and narrow palate, thick gums, short columella, and synophrys), 2 cases died of respiratory and circulatory failure, and 6 were still alive at the time of reporting, with an age range of 2 to 34 years. Blood and (or) cerebrospinal fluid lactate were elevated in all 8 patients. MRI in 7 cases manifested symmetrical abnormal signals in the brainstem, thalamus, and (or) basal ganglia. Urine organic acid test were all normal but 1 patient had alanine elevation. Five patients underwent respiratory chain enzyme activity testing, and all had varying degrees of enzyme activity reduction. Six variants were identified, 6 patients were homozygous variants, with c.322-10G>A was present in 4 patients from 2 families and 2 compound heterozygous variants. Conclusions: The clinical phenotype of COXPD32 is highly heterogenous and the severity of the disease varies from development delay, feeding difficulty, dystonia, high lactic acid, ocular symptoms and reduced mitochondrial respiratory chain enzyme activity in mild cases, which may survive into adulthood, to rapid death due to respiratory and circulatory failure in severe cases. COXPD32 needs to be considered in cases of unexplained acidosis, hyperlactatemia, feeding difficulties, development delay or regression, ocular symptoms, respiratory and circulatory failure, and symmetrical abnormal signals in the brainstem, thalamus, and (or) basal ganglia, and genetic testing can clarify the diagnosis.

Novel autoantibody targets identified in patients with autoimmune hepatitis (AIH) by PhIP-Seq reveals pathogenic insights

Autoimmune hepatitis (AIH) is a severe autoimmune disease, characterized by the presence of autoantibodies. However, the role of autoantibodies in the pathophysiology of AIH remains uncertain. Here, we employed Phage Immunoprecipitation-Sequencing (PhIP-Seq) to identify novel autoantibodies in AIH. Using these results, a logistic regression classifier was able to predict which patients had AIH, indicating the presence of a distinct humoral immune signature. To further investigate the autoantibodies most specific to AIH, significant peptides were identified relative to a broad array of controls (298 patients with non-alcoholic fatty liver disease (NAFLD), primary biliary cholangitis (PBC), or healthy controls). Top ranked autoreactive targets included SLA, the target of a well-recognized autoantibody in AIH, and disco interacting protein 2 homolog A (DIP2A). The autoreactive fragment of DIP2A shares a 9-amino acid stretch nearly identical to the U27 protein of HHV-6B, a virus found in the liver. In addition, antibodies against peptides derived from the leucine rich repeat N-terminal (LRRNT) domain of the relaxin family peptide receptor 1 (RXFP1) were highly enriched and specific to AIH. The enriched peptides map to a motif adjacent to the receptor binding domain, which is required for RXFP1 signaling. RXFP1 is a G protein-coupled receptor that binds relaxin-2, an anti-fibrogenic molecule shown to reduce the myofibroblastic phenotype of hepatic stellate cells. Eight of nine patients with antibodies to RXFP1 had evidence of advanced fibrosis (F3 or greater). Furthermore, serum from AIH patients positive for anti-RFXP1 antibody was able to significantly inhibit relaxin-2 signaling in the human monocytic cell line, THP1. Depletion of IgG from anti-RXFP1 positive serum abrogated this effect. These data provide supporting evidence that HHV6 plays a role in the development of AIH and point to a potential pathogenic role for anti-RXFP1 IgG in some patients. Identification of anti-RXFP1 in patient serum may enable risk stratification of AIH patients for fibrosis progression and lead to the development of novel strategies for disease intervention.

Liver transplantation immunology: Immunosuppression, rejection, and immunomodulation

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.

Addressing sex-based disparities in solid organ transplantation in the United States - a conference report

Solid organ transplantation provides the best treatment for end-stage organ failure, but significant sex-based disparities in transplant access exist. On June 25, 2021, a virtual multidisciplinary conference was convened to address sex-based disparities in transplantation. Common themes contributing to sex-based disparities were noted across kidney, liver, heart, and lung transplantation, specifically the existence of barriers to referral and wait listing for women, the pitfalls of using serum creatinine, the issue of donor/recipient size mismatch, approaches to frailty and a higher prevalence of allosensitization among women. In addition, actionable solutions to improve access to transplantation were identified, including alterations to the current allocation system, surgical interventions on donor organs, and the incorporation of objective frailty metrics into the evaluation process. Key knowledge gaps and high-priority areas for future investigation were also discussed.

Immunosuppression after pediatric liver transplant: The parents' perspective

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.

Prediction of knee pain improvement over two years for knee osteoarthritis using a dynamic nomogram based on MRI-derived radiomics: a proof-of-concept study

OBJECTIVES

To develop and validate a nomogram to detect improved knee pain in osteoarthritis (OA) by integrating magnetic resonance imaging (MRI) radiomics signature of subchondral bone and clinical characteristics.

METHODS

Participants were selected from the Vitamin D Effects on Osteoarthritis (VIDEO) study. The primary outcome was 20% improvement of knee pain score over 2 years in participants administrated either vitamin D or placebo. Radiomics features of subchondral bone and clinical characteristics from 216 participants were extracted and analyzed. The participants were randomly split into the training and validation cohorts at a ratio of 8:2. Least absolute shrinkage and selection operator (LASSO) regression was used to select features and generate radiomics signatures. The optimal radiomics signature and clinical indicators were fitted into a nomogram using multivariable logistic regression model.

RESULTS

The nomogram showed favorable discrimination performance [AUC_training, 0.79 (95% CI: 0.72-0.79), AUC_validation, 0.83 (95% CI: 0.70-0.96)] as well as a good calibration. Additional contributing value of fusion radiomics signature to the nomogram was statistically significant (NRI, 0.23; IDI, 0.14, P < 0.001 in training cohort and NRI, 0.29; IDI, 0.18, P < 0.05 in validating cohort). Decision curve analysis confirmed the clinical usefulness of nomogram.

CONCLUSION

The radiomics-based nomogram comprising the MR radiomics signature and clinical variables achieves a favorable predictive efficacy and accuracy in differentiating improvement in knee pain among OA patients. This proof-of-concept study provides a promising way to predict clinically meaningful outcomes.

Next-generation pathology detection of T cell-antigen-presenting cell immune synapses in human liver allografts

BACKGROUND AND AIMS

In otherwise near-normal appearing biopsies by routine light microscopy, next-generation pathology (NGP) detected close pairings (immune pairs; iPAIRs) between lymphocytes and antigen-presenting cells (APCs) that predicted immunosuppression weaning failure in pediatric liver transplant (LTx) recipients (Immunosuppression Withdrawal for Stable Pediatric Liver Transplant Recipients [iWITH], NCT01638559). We hypothesized that NGP-detected iPAIRs enrich for true immune synapses, as determined by nuclear shape metrics, intercellular distances, and supramolecular activation complex (SMAC) formation.

APPROACH AND RESULTS

Intralobular iPAIRs (CD45 high lymphocyte-major histocompatibility complex II + APC pairs; n = 1167, training set) were identified at low resolution from multiplex immunohistochemistry-stained liver biopsy slides from several multicenter LTx immunosuppression titration clinical trials (iWITH; NCT02474199 (Donor Alloantigen Reactive Tregs (darTregs) for Calcineurin Inhibitor (CNI) Reduction (ARTEMIS); Prospective Longitudinal Study of iWITH Screen Failures Secondary to Histopathology). After excluding complex multicellular aggregates, high-resolution imaging was used to examine immune synapse formation ( n = 998). By enriching for close intranuclear lymphocyte-APC distance (mean: 0.713 μm) and lymphocyte nuclear flattening (mean ferret diameter: 2.1), SMAC formation was detected in 29% of iPAIR-engaged versus 9.5% of unpaired lymphocytes. Integration of these morphometrics enhanced NGP detection of immune synapses (ai-iSYN). Using iWITH preweaning biopsies from eligible patients ( n = 53; 18 tolerant, 35 nontolerant; testing set), ai-iSYN accurately predicted (87.3% accuracy vs. 81.4% for iPAIRs; 100% sensitivity, 75% specificity) immunosuppression weaning failure. This confirmed the presence and importance of intralobular immune synapse formation in liver allografts. Stratification of biopsy mRNA expression data by immune synapse quantity yielded the top 20 genes involved in T cell activation and immune synapse formation and stability.

CONCLUSIONS

NGP-detected immune synapses (subpathological rejection) in LTx patients prior to immunosuppression reduction suggests that NGP-detected (allo)immune activity usefulness for titration of immunosuppressive therapy in various settings.

Selective decrease of donor-reactive Tregs after liver transplantation limits Treg therapy for promoting allograft tolerance in humans

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 (Tregs) 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 Treg (darTreg) 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 darTreg infusion, 5 received darTregs, and 4 were not infused because of failure to manufacture the minimal infusible dose of 100 × 106 cells. darTreg infusion was not associated with adverse events. Two darTreg-infused participants reached the primary endpoint, but an insufficient number of recipients were treated for assessing the efficacy of darTregs. Mechanistic studies revealed generalized Treg activation, senescence, and selective reduction of donor reactivity after liver transplantation. Overall, the ARTEMIS trial features a design concept for evaluating the efficacy of Treg therapy in transplantation. The mechanistic insight gained from the study may help guide the design of future trials.

Standardizing the histological assessment of late posttransplantation biopsies from pediatric liver allograft recipients

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.

Group B Streptococcus (GBS) colonisation is dynamic over time, whilst GBS capsular polysaccharides-specific antibody remains stable

Group B Streptococcus (GBS) is a leading cause of adverse pregnancy outcomes due to invasive infection. This study investigated longitudinal variation in GBS rectovaginal colonization, serum and vaginal GBS capsular polysaccharide (CPS)-specific antibody levels. Non-pregnant women were recruited in the UK and were sampled every 2 weeks over a 12-week period. GBS isolates were taken from recto-vaginal swabs and serotyped by polymerase chain reaction. Serum and vaginal immunoglobulin G (IgG) and nasal immunoglobulin A (IgA) specific to CPS were measured by Luminex, and total IgG/A by ELISA. Seventy women were enrolled, of median age 26. Out of the 66 participants who completed at least three visits: 14/47 (29.8%) women that were GBS negative at screening became positive in follow-up visits and 16/19 (84.2%) women who were GBS positive at screening became negative. There was 50% probability of becoming negative 36 days after the first positive swab. The rate of detectable GBS carriage fluctuated over time, although serum, vaginal, and nasal CPS-specific antibody levels remained constant. Levels of CPS-specific antibodies were higher in the serum of individuals colonized with GBS than in non-colonized, but similar in the vaginal and nasal mucosa. We found correlations between antibody levels in serum and the vaginal and nasal mucosa. Our study demonstrates the feasibility of elution methods to retrieve vaginal and nasal antibodies, and the optimization of immunoassays to measure GBS-CPS-specific antibodies. The difference between the dynamics of colonization and antibody response is interesting and further investigation is required for vaccine development.

Graft Fibrosis Over 10 to 15 Years in Pediatric Liver Transplant Recipients: Multicenter Study of Paired, Longitudinal Surveillance Biopsies

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.

Frailty, mortality, and health care utilization after liver transplantation: From the Multicenter Functional Assessment in Liver Transplantation (FrAILT) Study

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.

Saturated hydraulic conductivity of compacted steel slag-bentonite mixtures--A potential hydraulic barrier material of landfill cover

The feasibility of using steel slag and bentonite mixtures to construct the hydraulic barrier of a landfill cover was explored in the present study. Fine-grained steel slag (SS; particle diameter < 1 mm) and sodium-activated calcium bentonite (SACB) were used to prepare compacted specimens, and the saturated hydraulic conductivity (k_s) was measured using a flexible-wall permeameter. Influential factors including SACB content (BC), SS gradation, water-washing treatment of SS and compaction water content (ω_comp) were investigated. The hydraulic conductivity results were interpreted in microscopic scale through mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM). It was found that when BC was below 10%, the k_s value of the specimens prepared with well graded SS was about one order of magnitude lower than that of the specimens prepared with poorly graded SS. This was due to less macropores caused by better SS gradation. Yet, the effects of SS gradation on k_s diminished as BC further increased to 15%, suggesting the dominant role of BC on k_s at high BC. Water-washing treatment of SS helped reduce k_s significantly to 1.2 × 10^-10 m/s at BC of 10%, owing to less multivalent cations and hence lower osmotic swelling reduction caused by cations. Controlling ω_comp 1-2% wetter than the optimum water content (ω_opt) also helped reduce k_s significantly, owing to the reduction of macropores. Accordingly, it is suggested to use well-graded SS mixed with 10% SACB and then compact at ω_comp slightly wetter than ω_opt to the degree of compaction greater than 90% in engineering practice.

Not everything that counts can be counted: Tracking long-term outcomes in pediatric liver transplant recipients

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.

Transcriptomic profiling of blood from autoimmune hepatitis patients reveals potential mechanisms with implications for management

Autoimmune hepatitis (AIH) is a poorly understood, chronic disease, for which corticosteroids are still the mainstay of therapy and most patients undergo liver biopsy to obtain a diagnosis. We aimed to determine if there was a transcriptomic signature of AIH in the peripheral blood and investigate underlying biologic pathways revealed by gene expression analysis. Whole blood RNA from 75 AIH patients and 25 healthy volunteers was extracted and sequenced. Differential gene expression analysis revealed 249 genes that were significantly differentially expressed in AIH patients compared to controls. Using a random forest algorithm, we determined that less than 10 genes were sufficient to differentiate the two groups in our cohort. Interferon signaling was more active in AIH samples compared to controls, regardless of treatment status. Pegivirus sequences were detected in five AIH samples and 1 healthy sample. The gene expression data and clinical metadata were used to determine 12 genes that were significantly associated with advanced fibrosis in AIH. AIH patients with a partial response to therapy demonstrated decreased evidence of a CD8+ T cell gene expression signal. These findings represent progress in understanding a disease in need of better tests, therapies, and biomarkers.

The molecular phenotypes of injury, steatohepatitis, and fibrosis in liver transplant biopsies in the INTERLIVER study

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.

Advantages and Limitations of Clinical Scores for Donation After Circulatory Death Liver Transplantation

Background: Scoring systems have been proposed to select donation after circulatory death (DCD) donors and recipients for liver transplantation (LT). We hypothesized that complex scoring systems derived in large datasets might not predict outcomes locally. Methods: Based on 1-year DCD-LT graft survival predictors in multivariate logistic regression models, we designed, validated, and compared a simple index using the University of California, San Francisco (UCSF) cohort (n = 136) and a universal-comprehensive (UC)-DCD score using the United Network for Organ Sharing (UNOS) cohort (n = 5,792) to previously published DCD scoring systems. Results: The total warm ischemia time (WIT)-index included donor WIT (dWIT) and hepatectomy time (dHep). The UC-DCD score included dWIT, dHep, recipient on mechanical ventilation, transjugular-intrahepatic-portosystemic-shunt, cause of liver disease, model for end-stage liver disease, body mass index, donor/recipient age, and cold ischemia time. In the UNOS cohort, the UC-score outperformed all previously published scores in predicting DCD-LT graft survival (AUC: 0.635 vs. ≤0.562). In the UCSF cohort, the total WIT index successfully stratified survival and biliary complications, whereas other scores did not. Conclusion: DCD risk scores generated in large cohorts provide general guidance for safe recipient/donor selection, but they must be tailored based on non-/partially-modifiable local circumstances to expand DCD utilization.

Impact of Donor and Recipient Clinical Characteristics and Hepatic Histology on Steatosis/Fibrosis Following Liver Transplantation

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.

Non-invasive alloimmune risk stratification of long-term liver transplant recipients

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.

[Clinical and prognostic study of anti-N-methyl-D-aspartate receptor encephalitis children with paroxysmal sympathetic hyperactivity syndrome]

The data of clinical characteristics, medical cost and prognosis of 22 anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis children from the Department of Neurology, Capital Institute of Pediatrics between May 2018 and January 2021 were analyzed, and 6 of them occurred paroxysmal sympathetic hyperactivity syndrome (PSH). It was found that the anti-NMDAR encephalitis children with PSH had severer consciousness disorder [median Glasgow Coma Scale (GCS) score at admission: 7.5], longer duration of consciousness disorder (median time: 53 days), higher hospitalization cost (median cost: 230 000 RMB), severer neurological injury at onset [median modified Rankin Scale (mRS) score at admission: 4], and longer recovery time of neurological function (median time of mRS score recovered to 0-2: 7 months), compared with those without PSH (all P<0.05). Therefore, more attention should be paid to sympathetic excited symptoms of anti NMDAR encephalitis, and thus identify and intervene early on PSH to reduce the neurological damage and economic burden.

Serum cholesterol efflux capacity is associated with coronary plaque progression in patients with coronary heart disease

Background

Coronary plaque progression is a major risk factor of adverse cardiac events in patients with coronary heart disease (CHD). Emerging evidence showed that attenuated high-density lipoprotein (HDL) function measured by cholesterol efflux capacity (CEC) was associated with development of atherosclerosis independent of HDL cholesterol level. In this study, we sought to investigate whether CEC is a predictor for coronary plaque progression in CHD patients.

Methods

We consecutively enrolled CHD patients from January 2017 to August 2019 in our Hospital who underwent elective percutaneous coronary intervention and had at least one non-target coronary lesion. Follow-up coronary angiography were performed at around 12 months. Fluorescence-labeled cholesterol and J774 macrophages were used to measure the CEC of ApoB-depleted serum sample from all patients. Quantitative coronary angiography (QCA) was performed both at baseline and follow-up to analyze the plaque progression.

Results

A total of 430 CHD patients with 586 non-target coronary lesions were included in the final analysis. During a mean follow-up time of 381.04±59.52 days, patients with decreased CEC presented more severe plaque progression (net luminal loss in highest to lowest CEC quartile: 0.22±0.42mm vs 0.20±0.41mm vs 0.13±0.36mm vs 0.11±0.34mm, p=0.035). In multivariate analysis, baseline CEC was independently associated with coronary plaque progression after adjustment for traditional risk factors including HDL cholesterol and ApoA-I, no matter treated as categorical variable (OR: 0.382 [95% CI 0.180–0.781] for highest to lowest quartile) or continuous variable (OR: 0.522 [95% CI 0.373–0.714] for per SD increase]. Furthermore, CEC demonstrated a better power in predicting coronary plaque progression compared with HDL cholesterol concentration (AUC=0.644 vs 0.514).

Conclusions

This study suggests that HDL function reflected by serum CEC is an independent predictor for coronary plaque progression in CHD patients.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Natural Science Foundation of China, Shanghai Municipal Commission of Health and Family Planning

[An optimized protocol of meniscus cell extraction for single-cell RNA sequencing]

OBJECTIVE

To optimize the protocol of meniscus cell extraction to enhance the efficiency of cell suspension preparation and maintain a high cell viability for single-cell RNA sequencing.

METHODS

We compared the efficiency of the routine cell extraction methods (short-time digestion and long-time digestion) and the optimized protocol for obtaining meniscus cell suspensions by evaluating the cell number obtained and the cell viability. Single-cell RNA sequencing datasets were analyzed to evaluate the stability of the cell suspension prepared using the optimized protocol. The reliability of the optimized protocol was assessed by comparing the single-cell RNA sequencing dataset obtained by the optimized protocol with published single-cell RNA sequencing datasets of the meniscus.

RESULTS

The optimized protocol harvested a greater number of cells (over 1×10⁵) than the routine protocols. The cell suspension prepared with the optimized protocol showed a cell viability higher than 80%, the highest among the 3 methods. Analysis of single-cell RNA sequencing datasets showed that the ratio of the mitochondrial genes was below 20% in over 80% of the cells. CD34⁺ cells, MCAM⁺ cells and COL1A1⁺ cells were identified in the datasets. Comparison with the publish datasets showed that the optimized protocol was capable of harvesting COL3A1⁺, COL1A1⁺, MYLK⁺, BMP2⁺, CD93⁺ and CDK1⁺ cells.

CONCLUSION

Single-cell suspension prepared from the meniscus can be stably obtained using the optimized protocol for single-cell RNA sequencing using the 10× Genomics platform.

Atmospheric Carbon and Transport - America (ACT-America) Data Sets: Description, Management, and Delivery

The ACT-America project is a NASA Earth Venture Suborbital-2 mission designed to study the transport and fluxes of greenhouse gases. The open and freely available ACT-America data sets provide airborne in situ measurements of atmospheric carbon dioxide, methane, trace gases, aerosols, clouds, and meteorological properties, airborne remote sensing measurements of aerosol backscatter, atmospheric boundary layer height and columnar content of atmospheric carbon dioxide, tower-based measurements, and modeled atmospheric mole fractions and regional carbon fluxes of greenhouse gases over the Central and Eastern United States. We conducted 121 research flights during five campaigns in four seasons during 2016-2019 over three regions of the US (Mid-Atlantic, Midwest and South) using two NASA research aircraft (B-200 and C-130). We performed three flight patterns (fair weather, frontal crossings, and OCO-2 underflights) and collected more than 1,140 h of airborne measurements via level-leg flights in the atmospheric boundary layer, lower, and upper free troposphere and vertical profiles spanning these altitudes. We also merged various airborne in situ measurements onto a common standard sampling interval, which brings coherence to the data, creates geolocated data products, and makes it much easier for the users to perform holistic analysis of the ACT-America data products. Here, we report on detailed information of data sets collected, the workflow for data sets including storage and processing of the quality controlled and quality assured harmonized observations, and their archival and formatting for users. Finally, we provide some important information on the dissemination of data products including metadata and highlights of applications of ACT-America data sets.