Late graft loss or death in pediatric liver transplantation: an analysis of the SPLIT database

Key Aspects of Pediatric Liver Transplant Patient Visits to the Pediatric Emergency Department

OBJECTIVES

Patients with liver transplant can present to a pediatric emergency department with short- and long-term complications of transplant. Here, we described clinical features of pediatric liver transplant patients admitted to the pediatric emergency department and identified risk factors that may lead to pediatric intensive care unit admission.

MATERIALS AND METHODS

We retrospectively evaluated pediatric liver transplant patients admitted posttransplant to Baskent University Hospital's pediatric emergency department in 2023. We noted symptoms, laboratory tests, hospitalization status, and final diagnoses. We compared clinical and laboratory features of patients admitted or not admitted to the intensive care unit.

RESULTS

In 2023, 108 presentations of 33 liver transplant patients presented to our pediatric emergency department: 46.3% were girls, mean age was 7.79 ± 4.40 years, and median posttransplant day at time of emergency department visit was 622 days. Common symptoms were vomiting (48%), fever (46%), and rhinorrhea and cough (34%). Forty-nine visits (45.4%) resulted in hospitalization; 5 visits (4.6%) resulted in PICU admission, with 2 mortalities (1.8%). Final diagnoses included acute gastroenteritis and upper respiratory tract infections (23 patients) and lower respiratory tract infections (13 patients). Seven patients had cholangitis, 6 had intra-abdominal infection, and 5 had sepsis. Seizures and sepsis were significantly correlated with intensive care unit admission (P <.001). Patients admitted to the intensive care unit had significantly shorter time posttransplant versus other patients (518 ± 324 vs 1498 ± 1658 days; P < .001).

CONCLUSIONS

Half of patients who presented to the emergency department required hospitalization mainly for observation and supportive treatment, with a small number requiring intensive care unit admission. Nevertheless, physicians caring for liver transplant patients should be aware of serious complications and monitor patients closely, especially early posttransplant when intensive immunosuppressive treatment regimens are used.

Liver transplantation for pediatric liver malignancies

In the last few decades, collaboration between international pediatric oncology groups has resulted in significant improvement in survival after liver transplantation (LT) for pediatric liver tumors, and LT has become the accepted standard of care for unresectable pediatric liver tumors-either living donor liver transplantation or deceased donor liver transplantation. Hepatoblastoma and HCC are the common pediatric liver malignancies treated by LT, and LT is now the accepted treatment modality for unresectable nonmetastatic cases. The long-term survival rate is more than 80% in hepatoblastoma transplants. Furthermore, with the advent of living donor liver transplantation, the waitlist mortality, availability of a better graft quality with shorter ischemic times, and performance of LT with the appropriate timing between chemotherapy have all improved. Up to 80% of pediatric HCCs are unresectable, and studies have shown that LT for pediatric HCC has better outcomes than liver resection. Furthermore, LT has also shown better results than liver resection for cases of HCC not meeting Milan criteria. Given the rarity of pediatric liver malignancies and challenges in optimal management, a multidisciplinary treatment approach, research models building on what is already known, and consideration of newer treatment modalities are required for further improving the treatment of pediatric liver malignancies.

Adult provider role in transition of care for young adult pediatric recipients of liver transplant: An expert position statement

Health care transition (HCT) is the process of changing from a pediatric to an adult model of care. Young adult pediatric recipients of liver transplant transferring from pediatric to adult health care services are highly vulnerable and subject to poor long-term outcomes. Barriers to successful transition are multifaceted. A comprehensive HCT program should be initiated early in pediatrics and continued throughout young adulthood, even after transfer of care has been completed. It is critical that pediatric and adult liver transplant providers establish a partnership to optimize care for these patients. Adult providers must recognize the importance of HCT and the need to continue the transition process following transfer. While this continued focus on HCT is essential, current literature has primarily offered guidance for pediatric providers. This position paper outlines a framework with a sample set of tools for the implementation of a standardized, multidisciplinary approach to HCT for adult transplant providers utilizing "The Six Core Elements of HCT." To implement more effective strategies and work to improve long-term outcomes for young adult patients undergoing liver transplant, HCT must be mandated as a routine part of posttransplant care. Increased advocacy efforts with the additional backing and support of governing organizations are required to help facilitate these practices.

Immunosuppression minimization is safe and associated with good long-term success in pediatric recipients of liver transplant

Immunosuppression reduction after liver transplant is an important strategy to mitigate long-term medication side effects. We describe our center's experience with immunosuppression minimization to once-daily calcineurin inhibitor dosing. Success was defined as continuing daily calcineurin inhibitor monotherapy with normal transaminases and no rejection. We performed a retrospective review of eligible children who received a liver transplant between 2009 and 2016, had a surveillance biopsy, and were on twice-daily calcineurin inhibitor monotherapy. Twenty-eight of 51 eligible patients were minimized to daily calcineurin inhibitor with goal 12-hour trough detectable. Nineteen patients (68%) had 1-year success, and 17 (61%) had long-term success at a median follow-up of 5.0 years (interquartile range (IQR): 2.9-6.6). Minimization failure occurred at a median of 0.6 years (IQR: 0.3-1.0) after dose reduction. Patients with long-term success had lower aspartate aminotransferase levels prior to minimization compared to those who failed with a median of 28.0 IU/L (IQR: 20.5-32.0) versus 32.0 IU/L (IQR: 30.0-37.0), p = 0.047. The long-term success group demonstrated a trend toward greater recipients of liver transplant from living donors (53% vs. 18%, p = 0.07). At the time of the last follow-up at a median of 5.0 years (IQR: 2.9-6.1) after surveillance biopsy, most (73%) patients who failed had returned to twice-daily calcineurin inhibitor monotherapy, all had liver enzymes <2 times the upper limit of normal, and there were no patient deaths or graft losses. In conclusion, immunosuppression minimization is safe in pediatric recipients of liver transplant and should be considered to reduce long-term medication side effects and improve patient quality of life. Future studies are necessary to follow long-term outcomes and develop biomarkers to predict minimization success.

Changes in thoracic radio density after living donor liver transplantation

BACKGROUND

The outcomes after liver transplantation have greatly improved, which has resulted in greater focus on improving non-hepatic outcomes of liver transplantation. The present study aimed to evaluate thoracic spine radio density in children and adolescents after liver transplantation.

METHODS

A total of 116 patients who underwent living donor liver transplantation were retrospectively analyzed. The radio density at the eleventh thoracic vertebra was measured using computed tomography scan performed preoperatively then annually for 5 years postoperatively and subsequently every 2 or 3 years.

RESULTS

The mean thoracic radio density of male recipients of male grafts had the lowest values during the study. The radio density of patients receiving a graft from a female donor was higher than in recipients with grafts from males. Total mean radio density decreased for first 5 years postoperatively and then increased. Changes in radio density were equally distributed in both steroid withdrawal and no steroid withdrawal groups for 5 years, after which patients with steroid withdrawal had a greater increase. Changes in radio density were equally distributed in both the steroid withdrawal and no steroid withdrawal groups up to age 20, after which patients in the steroid withdrawal group had a greater increase.

CONCLUSIONS

Gender differences may affect the outcome of radio density changes after transplantation. Given the moderate association between thoracic radio density and bone mineral density in skeletally mature adults and further studies are needed to validate this relationship between thoracic radio density and bone mineral density changes in pediatric liver transplantation.

Defining the T cell transcriptional landscape in pediatric liver transplant rejection at single cell resolution

Acute cellular rejection (ACR) affects >80% of pediatric liver transplant recipients within 5 years, and late ACR is associated with graft failure. Traditional anti-rejection therapy for late ACR is ineffective and has remained unchanged for six decades. Although CD8+ T cells promote late ACR, little has been done to define their specificity and gene expression. Here, we used single-cell sequencing and immune repertoire profiling (10X Genomics) on 30 cryopreserved 16G liver biopsies from 14 patients (5 pre-transplant or with no ACR, 9 with ACR). We identified expanded intragraft CD8+ T cell clonotypes (CD8EXP) and their gene expression profiles in response to anti-rejection treatment. Notably, we found that expanded CD8+ clonotypes (CD8EXP) bore markers of effector and CD56hiCD161- 'NK-like' T cells, retaining their clonotype identity and phenotype in subsequent biopsies from the same patients despite histologic ACR resolution. CD8EXP clonotypes localized to portal infiltrates during active ACR, and persisted in the lobule after histologic ACR resolution. CellPhoneDB analysis revealed differential crosstalk between KC and CD8EXP during late ACR, with activation of the LTB-LTBR pathway and downregulation of TGFß signaling. Therefore, persistently-detected intragraft CD8EXP clones remain active despite ACR treatment and may contribute to long-term allograft fibrosis and failure of operational tolerance.

Implementing living-donor pediatric liver transplantation in Southern Vietnam: 15-year results and perspectives

BACKGROUND

ND2 in Ho Chi Minh City is currently the only public center that performs PLT in Southern Vietnam. In 2005, the first PLT was successfully performed, with support from Belgian experts. This study reviews the implementation of PLT at our center and evaluates the results and challenges.

METHODS

Implementation of PLT at ND2 required medico-surgical team building and extensive improvement of hospital facilities. Records of 13 transplant recipients from 2005 to 2020 were studied retrospectively. Short- and long-term complications, as well as the survival rates, were reported.

RESULTS

The mean follow-up time was 8.3 ± 5.7 years. Surgical complications included one case of hepatic artery thrombosis that was successfully repaired, one case of colon perforation resulting in death from sepsis, and two cases of bile leak that were drained surgically. PTLD was observed in five patients, of whom three died. There were no cases of retransplantation. The 1-year, 5-year, and 10-year patient survival rates were 84.6%, 69.2%, and 69.2%, respectively. There were no cases of complication or death among the donors.

CONCLUSION

Living-donor PLT was developed at ND2 for providing a life-saving treatment to children with end-stage liver disease. Early surgical complication rate was low, and the patient survival rate was satisfactory at 1 year. Long-term survival decreased considerably due to PTLD. Future challenges include surgical autonomy and improvement of long-term medical follow-up with a particular emphasis on prevention and management of Epstein-Barr virus-related disease.

Vascular thrombosis after pediatric liver transplantation: Is prevention achievable?

Background

Vascular thromboses (VT) are life-threatening events after pediatric liver transplantation (LT). Single-center studies have identified risk factors for intra-abdominal VT, but large-scale pediatric studies are lacking.

Methods

This multicenter retrospective cohort study of isolated pediatric LT recipients assessed pre- and perioperative variables to determine VT risk factors and anticoagulation-associated bleeding complications.

Results

Within seven postoperative days, 31/331 (9.37%) patients developed intra-abdominal VT. Open fascia occurred more commonly in patients with VT (51.61 vs 23.33%) and remained the only independent risk factor in multivariable analysis (OR = 2.84, p = 0.012). Patients with VT received more blood products (83.87 vs 50.00%), had significantly higher rates of graft loss (22.58 vs 1.33%), infection (50.00 vs 20.60%), and unplanned return to the operating room (70.97 vs 16.44%) compared to those without VT. The risk of bleeding was similar (p = 0.2) between patients on and off anticoagulation.

Conclusions

Prophylactic anticoagulation did not increase bleeding complications in this cohort. The only independent factor associated with VT was open fascia, likely a graft/recipient size mismatch surrogate, supporting the need to improve surgical techniques to prevent VT that may not be modifiable with anticoagulation.

Comparing the Outcomes of Pediatric Liver Transplantation

BACKGROUND

Liver transplantation is a life-saving treatment for end-stage pediatric liver failure. We aimed to present the results of pediatric liver transplants performed in our center in the last 11 years (between 2012 and March 2022) in association with prognostic factors affecting survival.

METHODS

Demographic characteristics, etiologic reasons, previous operations (Kasai procedure), morbidity, mortality, survival, and bilio-vascular complication rates were determined, and outcomes were evaluated. In the postoperative period, the duration of mechanical ventilation and intensive care unit stay and surgical and other complications were evaluated. Graft and patient survival rates were determined, and univariate and multivariate factors affecting these rates were evaluated.

RESULTS

In the last 10 years, 229 pediatric liver transplantaion (Pe-LT)/1513 adult liver taransplantation (Ad-LT) (21.35%) were performed in our center. This ratio (Pe-LT/Ad-LT ratio) is 1741/15,886 (10.95%) for our country. A total of 229 liver transplants were performed in 214 pediatric patients. Retransplantation was performed in 15 patients (6.55%). Cadaveric liver transplantation was performed in 9 patients. Graft survival rates were 87%, 83%, 78%, 78%, 78%, and 78% at <30 days, 30 to 90 days, 91 to 364 days, 1 to 3 years, and >3 years, respectively. Patient survival rates for <30 days, 30 to 90 days, 91 to 364 days, 1 to 3 years, and >3 years were 91.5%, 85.7%, 82%, 81.5%, and 81.5%, respectively. Our 5-year survival rates in metabolic diseases and the acute fulminant failure group are 93.8% and 100%, respectively.

CONCLUSIONS

The fact that the 1- and 5-year survival rates are the same shows that when patients overcome biliary vascular and infectious problems, their survival is prolonged.

T-cell infiltrate intensity is associated with delayed response to treatment in late acute cellular rejection in pediatric liver transplant recipients

BACKGROUND

Late acute cellular rejection (ACR) is associated with donor-specific antibodies (DSA) development, chronic rejection, and allograft loss. However, accurate predictors of late ACR treatment response are lacking. ACR is primarily T-cell mediated, yet B cells and plasma cells (PC) also infiltrate the portal areas during late ACR. To test the hypothesis that the inflammatory milieu is associated with delayed response (DR) to rejection therapy, we performed a single-center retrospective case-control study of pediatric late liver ACR using multiparameter immunofluorescence for CD4, CD8, CD68, CD20, and CD138 to identify immune cell subpopulations.

METHODS

Pediatric liver transplant recipients transplanted at <17 years of age and treated for biopsy-proven late ACR between January 2014 and 2019 were stratified into rapid response (RR) and DR based on alanine aminotransferase (ALT) normalization within 30 days of diagnosis. All patients received IV methylprednisolone as an initial rejection treatment. Immunofluorescence was performed on archived formalin-fixed paraffin embedded (FFPE) liver biopsy tissue.

RESULTS

Liver biopsies from 60 episodes of late ACR in 54 patients were included in the analysis, of which 33 were DR (55%). Anti-thymocyte globulin was only required in the DR group. The frequency of liver-infiltrating CD20+ and CD8+ lymphocytes and the prevalence of autoantibodies were higher in the DR group. In univariate logistic regression analysis, serum gamma-glutamyl transpeptidase (GGT) level at diagnosis, but not ALT, Banff score or presence of DSA, predicted DR.

CONCLUSIONS

Higher serum GGT level, presence of autoantibodies, and increased CD8+ T-cell infiltration portends DR in late ACR treatment in children.

Experience with the mTOR Inhibitor Everolimus in Pediatric Liver Graft Recipients

INTRODUCTION

Immunosuppression after pediatric liver transplantation remains a major challenge. MTOR inhibitors provide a promising therapeutic approach in combination with reduced CNI after transplantation. However, there are still few data regarding their use in children.

PATIENTS

We analyzed 37 patients with a median age of 10 years, who received Everolimus for one or more of the following indications: I = chronic graft dysfunction (n = 22); II = progressive renal impairment (n = 5); III = non-tolerable side effects with previous immunosuppressive medication (n = 6); and IV = malignancies (n = 10). The median follow-up time was 36 months.

RESULTS

Patient survival was 97%, and graft survival 84%, respectively. Stabilization of graft function was observed in 59% in subgroup 1, with 18.2% ultimately requiring retransplantation. No patient in subgroup IV developed recurrence of his primary tumor or PTLD by the endpoint of the study. Side effects were observed in 67.5% of the study patients, with infections being the most frequent (n = 20; 54.1%). There were no relevant effects on growth and development.

CONCLUSION

Everolimus seems to be a treatment option in selected pediatric liver graft recipients for whom other regimens are not suitable. Overall, the efficacy was good and the side effect profile appeared to be acceptable.

Outcome of split-liver transplantation from pediatric donors weighing 25 kg or less

The lower limit of body weight for "splitable" liver grafts remains unknown. To examine the outcome of split-liver transplantation (SLT) from pediatric donors ≤25 kg relative to conventional graft-type liver transplantation from deceased donors under corresponding conditions, a total of 158 patients who received primary liver transplantation, including 22 SLTs from donors ≤25 kg, 46 SLTs from donors >25 kg, 76 whole-liver transplantations, and 14 reduced-liver transplantations in donors ≤25 kg between January 2018 and December 2019, were included in the study. There was no significant difference in the complications, patient survival, and graft survival between each of the latter three groups and the SLT ≤25 kg group. Pediatric End-Stage Liver Disease (PELD) score was the independent predictor of graft loss (death or retransplantation). Graft weight was the independent predictor of hepatic artery thrombosis. SLT using well-selected pediatric donors ≤25 kg is an effective strategy to increase organ availability, especially for low-body-weight recipients, compared with conventional graft type from deceased donors under the condition of corresponding donor weight without increasing morbidity and mortality.

Health Care Transition for Adolescents and Young Adults With Pediatric-Onset Liver Disease and Transplantation: A Position Paper by the North American Society of Pediatric Gastroenterology, Hepatology, and Nutrition

Advances in medical therapies and liver transplantation have resulted in a greater number of pediatric patients reaching young adulthood. However, there is an increased risk for medical complications and morbidity surrounding transfer from pediatric to adult hepatology and transplant services. Health care transition (HCT) is the process of moving from a child/family-centered model of care to an adult or patient-centered model of health care. Successful HCT requires a partnership between pediatric and adult providers across all disciplines resulting in a transition process that does not end at the time of transfer but continues throughout early adulthood. Joint consensus guidelines in collaboration with the American Society of Transplantation are presented to facilitate the adoption of a structured, multidisciplinary approach to transition planning utilizing The Six Core Elements of Health Care Transition TM for use by both pediatric and adult specialists. This paper provides guidance and seeks support for the implementation of an HCT program which spans across both pediatric and adult hepatology and transplant centers.

Factors associated with improved patient and graft survival beyond 1 year in pediatric liver transplantation

With advances in surgical techniques, medical management, and more equitable allocation systems, children who receive a liver transplantation (LT) today can expect remarkable outcomes early after LT. However, beyond 1 year after transplant, attrition rates have not improved. We reviewed two separate eras (Era 1: January 1995-June 2004 vs. Era 2: July 2004-March 2018) of the Society of Pediatric Liver Transplantation registry to explore the evolution and associated factors contributing to late graft loss (LGL) and late mortality (LM). The fraction of long-term pediatric LT recipients surviving after 1 year with their first graft significantly improved (81.5% in Era 1 vs. 85.7% in Era 2; p < 0.0001). This improvement occurred despite significant changes in patient selection toward higher risk populations (p < 0.001) and without notable improvement in perioperative complications such as hepatic artery thrombosis (p = 0.24) and early posttransplant reoperation (p = 0.94) that have historically contributed to poor late-allograft outcomes. Improved outcomes were associated with changes in patient characteristics and perioperative practices, which subsequently impacted both early post-LT complications as well as other sequalae known to contribute to adverse events in long-term pediatric LT recipients. In conclusion, despite significant changes in patient selection toward higher risk populations, and without notable improvement in several perioperative complications known to contribute to poor late-allograft outcomes, significant improvements in LGL and a trend toward improvement in LM was seen in a more contemporary cohort of children receiving an LT.

Bone demineralization in a cohort of Egyptian pediatric liver transplant recipients: Single center pilot study

Liver transplantation (LT) is the definitive treatment of end-stage liver disease. The long-term survival following LT spurred more interest in improving the quality of life of patients. This was a cohort study that included 23 pediatric liver transplant recipients who underwent LT due to hereditary or metabolic liver diseases. Bone health assessment was performed at their last follow up clinically (anthropometric measures), biochemically and radiologically (Dual Energy X-ray Absorptiometry [DEXA] scans). Poor bone health was defined as z-score <-1. Mean age at LT was 5.77 years (standard deviation [SD] 3.64) and 43% were males. Biliary atresia was the most common cause of end stage liver disease (35%). Mean age at follow up was 14 years (SD 5.48) and mean follow up was 8 years (SD 4.12 years). Eleven patients (48%) had poor bone health (osteopenia 22% and osteoporosis 26%). On univariate analysis, being on steroids at last follow up (odds ratio [OR] 13.2, 95% confidence interval [CI] 1.23-140.67, P = .03), weight at last follow up (OR 0.45, 95% CI 0.20-0.99, P = .04), platelets at last follow up (OR 0.98, 95% CI 0.96-s0.99, P = .02), hemoglobin at last follow up (OR 0.33, 95% CI 0.12-0.89, P = .03) were significantly associated with poor bone health. None of the variables were significant on multivariate analysis. At most recent follow up, 48% of patients demonstrated poor bone health by DEXA scans. More studies are required to evaluate predictors of poor bone health after LT in children.

The Role of Dynamic DNA Methylation in Liver Transplant Rejection in Children

Transcriptional regulation of liver transplant (LT) rejection may reveal novel predictive and therapeutic targets. The purpose of this article is to test the role of differential DNA methylation in children with biopsy-proven acute cellular rejection after LT.

Recipient Age Predicts 20-Year Survival in Pediatric Liver Transplant

INTRODUCTION

Pediatric liver transplant recipients have demonstrated excellent long-term survival. The purpose of this analysis is to investigate factors associated with 20-year survival to identify areas for improvement in patient care.

METHODS

Kaplan-Meier with log-rank test as well as univariate and multivariate logistic regression methods were used to retrospectively analyze 4,312 liver transplant recipients under the age of 18 between September 30, 1987 and March 9, 1998. Our primary endpoint was 20-year survival among one-year survival.

RESULTS

Logistic regression analysis identified recipient age as a significant risk factor, with recipients below 5 years old having a higher 20-year survival rate (p < 0.001). A preoperative primary diagnosis of a metabolic dysfunction was found to be protective compared to other diagnoses (OR 1.64, CI 1.20-2.25). African-American ethnicity (OR 0.71, CI 0.58-0.87) was also found to be a risk factor for mortality. Technical variant allografts (neither living donor nor cadaveric) were not associated with increased or decreased rates of 20-year survival.

CONCLUSIONS

Our analysis suggests that long-term survival is inversely correlated with recipient age following pediatric liver transplant. If validated with further studies, this conclusion may have profound implications on the timing of pediatric liver transplantation.

Pediatric Liver Transplantation

Liver transplantation (LT) for children results in excellent short- and long-term patient and graft survival. LT is a lifesaving procedure in children with acute or chronic liver disease, hepatic tumors, and select genetic metabolic diseases in which it can significantly improve quality of life. In this article, the authors discuss the unique aspects of pediatric LT, including the indications, appropriate patient selection and evaluation, allocation of organs, transplant surgery including the use of variant grafts, posttransplant care including immunosuppression management, prognosis, and transition of care.

A network-based approach to identify expression modules underlying rejection in pediatric liver transplantation

Selecting the right immunosuppressant to ensure rejection-free outcomes poses unique challenges in pediatric liver transplant (LT) recipients. A molecular predictor can comprehensively address these challenges. Currently, there are no well-validated blood-based biomarkers for pediatric LT recipients before or after LT. Here, we discover and validate separate pre- and post-LT transcriptomic signatures of rejection. Using an integrative machine learning approach, we combine transcriptomics data with the reference high-quality human protein interactome to identify network module signatures, which underlie rejection. Unlike gene signatures, our approach is inherently multivariate and more robust to replication and captures the structure of the underlying network, encapsulating additive effects. We also identify, in an individual-specific manner, signatures that can be targeted by current anti-rejection drugs and other drugs that can be repurposed. Our approach can enable personalized adjustment of drug regimens for the dominant targetable pathways before and after LT in children.

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.

Three decades' analysis of pediatric liver transplantation outcomes reveals limited long-term improvements

BACKGROUND

The aim of this study was to assess improvements in long-term survival of pediatric patients after liver transplantation by analyzing outcomes in transplant recipients who survived beyond 1 year after transplantation. There has been a marked increase in the 1-year survival of pediatric patients, from 78% in transplant recipients between 1987 and 1990 to 95% in transplant recipients between 2011 and 2017. The long-term outcomes have not seen a similar trend, creating a disparity that warrants analysis.

METHODS

We analyzed 13 753 pediatric patients who survived for 1 year after receiving orthotopic liver transplantation between 1987 and 2017. The study period was divided into six eras. Outcomes were analyzed using the Kaplan-Meier method for time-to-event analysis, and multivariable Cox regression.

RESULTS

There were no significant gains in long-term outcomes among 1-year survivors over the past three decades. Log-rank tests for equality of survivor functions between each era and 1987-1990 were not statistically significant. Cause of death analysis revealed that although infections caused 20.6% of deaths in patients transplanted between 1987 and 1990, this number dropped to 5.6% in those transplanted between 2011 and 2017 (p = .01). Malignancy caused 10.6% of deaths in 1987-1990 but caused 22.2% of the deaths in 2011-2017 (p = .04).

CONCLUSION

Despite the gratifying gains in short-term survival of pediatric patients, 1-year survivors have no significant improvements in long-term survival after undergoing a liver transplantation. Long-term sequelae of immunosuppression, such as malignancy and infection, continue to be the most common causes of death. This study highlights the necessity for better long-term management of immunosuppression.

Protocol liver biopsies in stable long-term pediatric liver transplant recipients: risk or benefit?

BACKGROUND

Follow-up after pediatric liver transplantation (LTX) is challenging and needs to be refined to extend graft survival as well as general functional health and patients´ quality of life. Strategies towards individual immunosuppressive therapy seem to play a key role. Our aim was to evaluate protocol liver biopsies (PLB) as a tool in personalized follow up after pediatric LTX.

PATIENTS AND METHODS

Our retrospective analysis evaluates 92 PLB in clinically asymptomatic pediatric patients after LTX between 2009 and 2019. Histological findings were characterized using the Desmet scoring system. In addition to PLB, other follow-up tools like laboratory parameters, ultrasound imaging and transient elastography were evaluated. Risk factors for development of fibrosis or inflammation were analyzed.

RESULTS

PLB revealed a high prevalence of graft fibrosis (67.4%) and graft inflammation (47.8%). Graft inflammation was significantly (P = 0.0353*) more frequent within the first 5 years after transplantation compared to later time points. Besides conventional ultrasound, the measurement of liver stiffness using transient elastography correlate with stage of fibrosis (r = 0.567, P = <0.0001***). Presence of donor-specific anti-human leukocyte antigen antibodies in blood correlates with grade of inflammation in PLB (r = 0.6040, P = 0.0018 **). None of the patients who underwent PLB suffered from intervention-related complications. Histopathological results had an impact on clinical decision making in one-third of all patients after PLB.

CONCLUSION

PLB are a safe and useful tool to detect silent immune-mediated allograft injuries in the context of normal liver parameters.

Inferior outcomes in young adults undergoing liver transplantation - a UK and Ireland cohort study

Graft loss incidence is reported to be inversely related to recipient age. We used a national cohort of liver transplant (LT) recipients from the United Kingdom and Ireland to compare the age-dependent risk of graft failure in different post-transplantation time-periods ('epochs'). A cohort of first-time LT recipients (1995-2016) were identified (11 006). Cox regression was used to estimate hazard ratios (HR) comparing graft loss between age-groups (18-29, 30-39, 40-49, 50-59 and 60-76 years) and graft loss in different post-transplant epochs: 0-90 days, 90 days-2 years and 2-10 years. The risk of graft failure was highest in those transplanted between age 18 and 29 (adjusted HR 1.25, 95% CI: 1.00-1.57, P = 0.04) and in those aged 30-39 (adjusted HR 1.31, 95% CI: 1.11-1.55, P = 0.02). Graft failure in those under the age of 40 was similar in the first 90 days but worse 2-10 years' post-LT (18-29 years HR 1.36, 95% CI: 0.96-1.93, P < 0.001). Graft failure because of chronic rejection (CR) was more common in recipients aged 18-29 (P < 0.001). Adults transplanted between age 18 and 39 are at risk of late graft loss. CR is a concern for young adults (18-29 years). Our data highlights the need for specialist young adult services within adult healthcare.

Long-term Follow-up of a Randomized Trial of Tacrolimus or Cyclosporine A Microemulsion in Children Post Liver Transplantation

The aim of this study was to determine the long-term efficacy and safety of tacrolimus (Tac) and cyclosporine immunosuppression in pediatric liver transplantation (LTx).

Risk Factors Affecting Outcomes in Pediatric Liver Transplantation: A Real-World Single-Center Experience

Background

Despite liver transplantation (LT) being the standard treatment for pediatric end-stage liver disease, complications often persist and can adversely affect the post-transplant outcomes. This study aimed to identify the risk factors affecting the outcomes in pediatric LT patients.

Material/Methods

Data from pediatric patients who underwent primary LT from March 1988 to December 2018 were retrospectively analyzed. Chronic liver disease was defined as an explanted liver showing fibrosis regardless of grade, cirrhosis, or any other underlying disease that may cause progressive liver injury leading to fibrosis or cirrhosis.

Results

A total of 255 pediatric patients underwent LT during the study period. Their 1-, 5-, and 10-year overall survival rates were 90.5%, 88.4%, and 87.8%, respectively. According to multivariate analysis, while liver disease without underlying chronic liver disease (P=0.024) and a pediatric end-stage liver disease (PELD) score ≥30 (P=0.036) were the only factors associated with worse survival, body weight <6 kg (P=0.050), whole-liver DDLT compared to LDLT (P=0.001), fulminant liver failure (P=0.008), and postoperative hepatic artery complications (P<0.001) were associated with worse graft survival. Liver disease without underlying chronic liver disease was the only factor independently associated with hepatic artery complications (P=0.003).

Conclusions

Greater caution is recommended in pediatric patients with liver disease unaccompanied by underlying chronic liver disease, high PELD score, or low body weight to improve survival after LT. Hepatic artery complication was the only surgical complication affecting the graft survival outcome, especially in patients having liver disease without underlying chronic liver disease.

Efficacy and Safety of Immunosuppression Withdrawal in Pediatric Liver Transplant Recipients: Moving Toward Personalized Management

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.

Variation in immunosuppression practices among pediatric liver transplant centers-Society of Pediatric Liver Transplantation survey results

BACKGROUND

Variation in IS exists among pediatric liver transplant centers. While individual centers may publish their practice paradigms, current data on practices as a whole are lacking. This study sought to ascertain the IS protocols of pediatric liver transplant centers within the SPLIT to better understand variability and similarities among peer institutions.

METHODS

A 27-item questionnaire was developed within the SPLIT Quality Improvement and Clinical Care Committee. The survey collected data regarding center demographics, IS practices, and treatment of acute cellular rejection.

RESULTS

Twenty-eight (64%) SPLIT centers responded with 22 (79%) centers performing more than 10 transplants per year and 17 (61%) following more than 100 post-transplant recipients. All centers use a written protocol, and 25 (89%) have a dedicated transplant pharmacist/PharmD. Twenty-five (89%) centers use steroids for induction alone or in combination with thymoglobulin/interleukin-2 antibodies. All centers use tacrolimus for initial maintenance therapy. Most centers have specialized protocols for ABO-incompatible transplants, recipients with renal dysfunction, autoimmune liver diseases, and liver tumors. Treatment of rejection varied but was associated with escalation in IS.

CONCLUSION

IS practices among pediatric liver transplant centers are similar including the use of written protocols, pharmacy involvement, steroids for induction, tacrolimus as initial IS, tacrolimus reduction/delay for renal dysfunction, and escalation of IS with rejection severity. However, other IS practices show wide variability including treatment for ABO-incompatible grafts and presumed rejection. This study serves as a foundation to guide prospective research linking IS practice to outcomes to determine best practice.

Living donor liver transplantation for pediatric patients with metabolic disease vs. deceased donation

BACKGROUND

There are conflicting reports on the outcomes of patients with metabolic liver disease after liver transplantation. We aimed to compare the outcomes of living donor liver transplantation (LDLT) for metabolic disease vs orthotopic liver transplantation (OLT) from deceased donation.

METHODS

Clinical data of 89 patients undergoing liver transplantation for the treatment of metabolic disorders were reviewed. Pre- and peri-transplant demographics, survival rate, complications and laboratory test data were collected and analyzed.

RESULTS

For the 89 patients, only 2 died by the end of the last follow-up. The post-transplant EAD rate and severe complications were higher for OLT than LDLT. No significant difference was found between LDLT and OLT for the incidence of EBV and CMV infections. In terms of laboratory indexes, the recovery time of PLT, AKP and AST levels were significantly longer for OLT than LDLT. Among different types of metabolic disease, no significant difference was found in viral infection, EAD, laboratory indexes, severe complications or duration of hospital stay.

CONCLUSIONS

LDLT shows a lower incidence rate of EAD and complications, while it also shows a 1-year survival rate and incidence of viral infections compared similar to that of OLT. LDLT is the better treatment option of pediatric liver transplantation for metabolic liver disease compared with OLT.

Decreased Incidence of Hepatic Artery Thrombosis in Pediatric Liver Transplantation Using Technical Variant Grafts: Report of the Society of Pediatric Liver Transplantation Experience

OBJECTIVE

To evaluate risk factors for hepatic artery thrombosis (HAT) and examine the long-term outcomes of graft and patient survival after HAT in pediatric recipients of liver transplantation.

STUDY DESIGN

Using multicenter data from the Society of Pediatric Liver Transplantation, Kaplan-Meier and Cox regression analyses were performed on first-time pediatric (aged <18 years) liver transplant recipients (n = 3801) in the US and Canada between 1995 and 2016.

RESULTS

Of children undergoing their first liver transplantation, 7.4% developed HAT within the first 90 days of transplantation and, of those who were retransplanted, 20.7% developed recurrent HAT. Prolonged warm ischemia times increased the odds of developing HAT (OR, 1.11; P = .02). Adolescents aged 11-17 years (OR, 0.53; P = .03) and recipients with split, reduced, or living donor grafts had decreased odds of HAT (OR, 0.59; P < .001 compared with whole grafts). Fifty percent of children who developed HAT developed graft failure within the first 90 days of transplantation (adjusted hazard ratio, 11.87; 95% CI, 9.02-15.62) and had a significantly higher post-transplant mortality within the first 90 days after transplantation (adjusted hazard ratio, 6.18; 95% CI, 4.01-9.53).

CONCLUSIONS

These data from an international registry demonstrate poorer long-term graft and patient survival in pediatric recipients whose post-transplant course is complicated by HAT. Notably, recipients of technical variant grafts had lower odds of HAT compared with whole liver grafts.

Outcomes of Pediatric Liver Transplantation in Korea Using Two National Registries

Background: This retrospective study aimed to evaluate overall survival and the risk factors for mortality among Korean pediatric liver transplantation (LT) patients using data from two national registries: the Korean Network Organ Sharing (KONOS) of the Korea Centers for Disease Control and Prevention and the Korean Organ Transplantation Registry (KOTRY). Methods: Prospectively collected data of 755 pediatric patients who underwent primary LT (KONOS, February 2000 to December 2015; KOTRY, May 2014 to December 2017) were retrospectively reviewed. Results: The 1-, 5-, 10-, and 15-year survival rates were 90.6%, 86.7%, 85.8%, and 85.5%, respectively, in KONOS, and the 1-month, 3-month, 1-year, and 2-year survival rates were 92.1%, 89.4%, 89.4%, and 87.2%, respectively, in KOTRY. There was no significant difference in survival between the two registries. Multivariate analysis identified that body weight ≥6 kg (p <0.001), biliary atresia as underlying liver disease (p = 0.001), and high-volume center (p < 0.001) were associated with better survival according to the KONOS database, while hepatic artery complication (p < 0.001) was associated with poorer overall survival rates according to the KOTRY database. Conclusion: Long-term pediatric patient survival after LT was satisfactory in this Korean national registry analysis. However, children with risk factors for poor outcomes should be carefully managed after LT.

Glutathione S-Transferase T1 Mismatch Is a Risk Factor for Chronic Ductopenic Rejection of Liver Allografts

The underlying causes of chronic rejection (CR) after liver transplantation (LT) are not completely known. The main aim of this study was to explore the involvement of the minor histocompatibility antigen glutathione S-transferase T1 (GSTT1) in CR. We retrospectively studied 611 patients who underwent LTs at University Hospital Virgen del Rocío between 2003 and 2016 with a median follow-up of 7.4 ± 4.2 years. The GSTT1 genotype was determined by polymerase chain reaction. We defined GSTT1 mismatch as a specific donor/recipient combination in which a recipient who was homozygous for the deletion allele received a transplant from a positive donor. The prevalence of CR in our whole cohort was 11.6% (71/611), and the prevalence in the GSTT1-mismatched group was 18.8% (16/85) versus 10.5% (55/526) in the GSTT1-matched group. In the cyclosporine A (CsA) group, the prevalence was 26.3% (26/99), much higher than the 8.8% (45/512) observed in the tacrolimus (Tac) group. For statistical analysis, the patients were distributed into 2 groups: group 1, regarded as GSTT1 mismatched, which included the donor (D)+/recipient (R)- allelic combination; and group 2, regarded as GSTT1 matched, which included the other allelic combinations of D+/R+, D-/R-, and D-/R+. All relevant clinical information was collected, and a diagnosis of CR was always confirmed by liver biopsy. GSTT1 mismatch (hazard ratio [HR], 1.99; 95% confidence interval [CI], 1.08-3.66; P = 0.03) and use of CsA/Tac (P < 0.001) were independent risk factors for CR. CR increased the risk of mortality (HR, 2; 95% CI, 1.2-3.6; P = 0.01). Out of the 71 CR patients, 12 (16.9%) needed retransplantation. In conclusion, the GSTT1 D+/R- allelic mismatch is an independent risk factor for CR. A long follow-up of LT patients is recommended because the incidence of CR in adults seems to be underestimated.

Society of pediatric liver transplantation: Current registry status 2011-2018

BACKGROUND

SPLIT was founded in 1995 in order to collect comprehensive prospective data on pediatric liver transplantation, including waiting list data, transplant, and early and late outcomes. Since 2011, data collection of the current registry has been refined to focus on prospective data and outcomes only after transplant to serve as a foundation for the future development of targeted clinical studies.

OBJECTIVE

To report the outcomes of the SPLIT registry from 2011 to 2018.

METHODS

This is a multicenter, cross-sectional analysis characterizing patients transplanted and enrolled in the SPLIT registry between 2011 and 2018. All patients, <18 years of age, received a first liver-only, a combined liver-kidney, or a combined liver-pancreas transplant during this study period.

RESULTS

A total of 1911 recipients from 39 participating centers in North America were registered. Indications included biliary atresia (38.5%), metabolic disease (19.1%), tumors (11.7%), and fulminant liver failure (11.5%). Greater than 50% of recipients were transplanted as either Status 1A/1B or with a MELD/PELD exception score. Incompatible transplants were performed in 4.1%. Kaplan-Meier estimates of 1-year patient and graft survival were 97.3% and 96.6%. First 30 days of surgical complications included reoperation (31.7%), hepatic artery thrombosis (6.3%), and portal vein thrombosis (3.2%). In the first 90 days, biliary tract complications were reported in 13.6%. Acute cellular rejection during first year was 34.7%. At 1 and 2 years of follow-up, 39.2% and 50.6% had normal liver tests on monotherapy (tacrolimus or sirolimus). Further surgical, survival, allograft function, and complications are detailed.

Changing Etiologies and Prognostic Factors in Pediatric Acute Liver Failure

After the implementation of universal hepatitis A virus vaccination in Argentina, the outcome of pediatric acute liver failure (PALF) remains unknown. We aimed to identify variables associated with the risk of liver transplantation (LT) or death and to determine the causes and short-term outcomes of PALF in Argentina. We retrospectively included 135 patients with PALF listed for LT between 2007 and 2016. Patients with autoimmune hepatitis (AIH), Wilson's disease (WD), or inborn errors of metabolism (IEM) were classified as PALF-chronic liver disease (CLD), and others were classified as "pure" PALF. A logistic regression model was developed to identify factors independently associated with death or need of LT and risk stratification. The most common etiologies were indeterminate (52%), AIH (23%), WD (6%), and IEM (6%). Overall, transplant-free survival was 35%, whereas 50% of the patients underwent LT and 15% died on the waiting list. The 3-month risk of LT or death was significantly higher among patients with pure PALF compared with PALF-CLD (76.5% versus 42.5%; relative risk, 1.8 [1.3-2.5]; P < 0.001), and 3 risk factors were independently associated with worse outcome: international normalized ratio (INR) ≥3.5 (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.3-7.2]), bilirubin ≥17 mg/dL (OR, 4.4; 95% CI, 1.9-10.3]), and pure PALF (OR, 3.8; 95% CI, 1.6-8.9). Patients were identified by the number of risk factors: Patients with 0, 1, or ≥2 risk factors presented a 3-month risk of worse outcome of 17.6%, 36.6%, and 82%, respectively. In conclusion, although lacking external validation, this simple risk-staging model might help stratify patients with different transplant-free survival rates and may contribute to establishing the optimal timing for LT.

De novo malignancies after liver transplantation: The effect of immunosuppression-personal data and review of literature

BACKGROUND

Immunosuppression has undoubtedly raised the overall positive outcomes in the post-operative management of solid organ transplantation. However, long-term exposure to immunosuppression is associated with critical systemic morbidities. De novo malignancies following orthotopic liver transplants (OLTs) are a serious threat in pediatric and adult transplant individuals. Data from different experiences were reported and compared to assess the connection between immunosuppression and de novo malignancies in liver transplant patients.

AIM

To study the role of immunosuppression on the incidence of de novo malignancies in liver transplant recipients.

METHODS

A systematic literature examination about de novo malignancies and immunosuppression weaning in adult and pediatric OLT recipients was described in the present review. Worldwide data were collected from highly qualified institutions performing OLTs. Patient follow-up, immunosuppression discontinuation and incidence of de novo malignancies were reported. Likewise, the review assesses the differences in adult and pediatric recipients by describing the adopted immunosuppression regimens and the different type of diagnosed solid and blood malignancy.

RESULTS

Emerging evidence suggests that the liver is an immunologically privileged organ able to support immunosuppression discontinuation in carefully selected recipients. Malignancies are often detected in liver transplant patients undergoing daily immunosuppression regimens. Post-transplant lymphoproliferative diseases and skin tumors are the most detected de novo malignancies in the pediatric and adult OLT population, respectively. To date, immunosuppression withdrawal has been achieved in up to 40% and 60% of well-selected adult and pediatric recipients, respectively. In both populations, a clear benefit of immunosuppression weaning protocols on de novo malignancies is difficult to ascertain because data have not been specified in most of the clinical experiences.

CONCLUSION

The selected populations of tolerant pediatric and adult liver transplant recipients greatly benefit from immunosuppression weaning. There is still no strong clinical evidence on the usefulness of immunosuppression withdrawal in OLT recipients on malignancies. An interesting focus is represented by the complete reconstitution of the immunological pathways that could help in decreasing the incidence of de novo malignancies and may also help in treating liver transplant patients suffering from cancer.

20- to 25-year patient and graft survival following a single pediatric liver transplant-Analysis of the United Network of Organ Sharing database: Where to go from here

To understand factors contributing to liver graft loss and patient death, we queried a national database designed to follow pediatric patients transplanted between 1987 and 1995 till adulthood. A comparison was made to a cohort transplanted between 2000 and 2014. The 5-, 10-, 15-, 20-, and 25-year patient survival and graft survival were 95.5%, 93.7%, 89.1%, 80.8%, and 73.1%, and 92.5%, 86.7%, 77.6%, 68.7%, and 62.2%, respectively. The twenty-year patient/graft survival was significantly worse in those transplanted between 5 and 17 years of age compared to those transplanted at <5 years of age (P < 0.001). For the modern era cohort, the 3-year patient survival was significantly lower in children transplanted at 16-17 years of age compared to those transplanted at <5 and 11-15 years of age (P ≤ 0.02). The 3-year graft survival was similarly lower in children transplanted at 16-17 years of age compared to those transplanted at <5, 5-10, and 11-15 years of age (P ≤ 0.001). Infection as a cause of death occurred either early or >15 years post-transplant. Chronic rejection remained the leading cause of graft loss in both cohorts and the commonest indication for retransplantation 20-25 years following primary transplant. Further research is required to identify modifiable factors contributing to development of chronic rejection.

Transplant-free Survival in Chronic Liver Disease Presenting as Acute Liver Failure in Childhood

BACKGROUND

In adults, the absence of a preexisting chronic liver disease (CLD) is required to diagnose acute liver failure (ALF). The pediatric classification does not consider this aspect, thus previous studies pooled together children with ALF and children with unknown CLD presenting with acute hepatic decompensation (ALF-CLD). We aimed to compare prevalence, features, and outcome of children with ALF-CLD to those with a proper ALF.

METHODS

Patients admitted between 1996 and 2017 because of ALF defined by Pediatric Acute Liver Failure criteria (raised transaminases, International Normal Ratio ≥2.0, no history of liver disease) were classified as ALF-CLD if diagnosed with autoimmune hepatitis, Wilson disease, Budd-Chiari syndrome, hepatitis B virus reactivation, inborn errors of metabolism. The others were classified as ALF.

RESULTS

Seventy-four children (median age, 4 years; 1.0-8.8; male/female, 36/38] with ALF were found; 18 of <1 year of age were excluded. Fifty-six (median age, 6.6 years; 2.7-11.7; male/female, 23/33], 22 with ALF-CLD (autoimmune hepatitis, n = 14; Wilson disease, n = 6; inborn errors of metabolism, n = 2) and 34 with ALF (paracetamol overdose, n = 6; viral infections, n = 3; mushroom poisoning, n = 5; indeterminate, n = 20) were compared. In ALF-CLD, the median age at onset was higher, alanine aminotransferase, albumin, and International Normal Ratio levels were lower, splenomegaly, ascites, and cirrhosis were more common (all P < 0.01). On multivariate analysis, the diagnosis of ALF-CLD was an independent predictor of transplant-free survival (P = 0.006).

CONCLUSIONS

In children, ALF-CLD is common, has peculiar features, and is associated with a favorable outcome. This study suggests the need to distinguish this entity from other forms of ALF in children.

Evidence of Chronic Allograft Injury in Liver Biopsies From Long-term Pediatric Recipients of Liver Transplants

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.

Liver Transplantation in Children

Liver transplantation (LT) for children has excellent short- and long-term patient and graft survival. LT is a lifesaving procedure in children with acute or chronic liver disease, hepatic tumors, and a few genetic metabolic diseases in which it can significantly improve quality of life. In this article, the authors discuss the unique aspects of pediatric LT, including the indications, patient selection and evaluation, allocation, transplant surgery and organ selection, posttransplant care, prognosis, adherence, and transition of care.

Microwave ablation combined with transcatheter arterial chemoembolization is effective for treating unresectable hepatoblastoma in infants and children

The present study is to evaluate the feasibility and efficacy of microwave ablation (MWA) combined with transcatheter arterial chemoembolization (TACE) in the treatment for unresectable hepatoblastoma in infants and children. A total of 17 patients with PRETEXT stage III and IV hepatoblastoma that was unresectable by conventional resection were included in the present study. The patients were treated with TACE, MWA, and chemotherapy. All cases were diagnosed by computed tomography (CT) and liver tumor biopsy before TACE procedure. All patients received 2 courses of TACE and 1 to 2 times of MWA. Finally, several cycles of chemotherapy were arranged. Among the 17 patients, 14 were alive and had normal alpha-fetoprotein (AFP) levels. The other 3 patients died from tumor progression. The follow-up periods ranged from 10 to 68 months. Complete ablation was achieved in the 14 patients (14/17, 82.35%). Most patients were well tolerated during the whole course except for 1 patient with pneumonedema after TACE and another 1 with biloma after MWA. No marked chemotherapeutic agent-induced toxicity occurred. After chemotherapy or TACE, transient blood indicators and symptoms were observed as follows: myelosuppression, abnormal liver function, gross hematuria, fever, and abdominal pain. Transient symptoms after MWA were fever, abdominal pain, and massive gross hematuria. The present study demonstrates that MWA combined with TACE is a safe and effective method for treating unresectable hepatoblastoma in infants and children with controllable side effects.

Histological findings in protocol biopsies following pediatric liver transplant: Low incidence of abnormalities at 5 years

Histological abnormalities, including chronic hepatitis, fibrosis, and steatosis, are increasingly reported in liver biopsies of children after LT. These changes may be progressive and represent a form of rejection. Liver biochemistry is often initially normal. Our LT program began in 2002, utilizing tacrolimus and low-dose steroids for the first year post-LT. Patients undergo a protocol biopsy at 1 year post-LT prior to stopping steroids, then at 5 years and every 5 years thereafter. Target tacrolimus levels are 5-8 μg/L and 3-5 μg/L after 3 and 12 months, respectively. Between 2002 and 2009, 51 LT were performed; 50 (98%) and 49 (96%) patients survived for 1 and 5 years, respectively. A total of 43 patients (median age at LT 2.3 years) underwent a protocol biopsy at 1 year (16 male; median time post-LT 12.5 months), and 44 (20 male; median time post-LT 5.1 years) at 5 years. By 5 years, 3 had transferred to adult services; 1 was re-transplanted for graft failure and 1 moved overseas. Biopsies were reviewed by 2 pathologists. Most patients (31/44) were on tacrolimus monotherapy at 5 years. At 1 and 5 years, 29 of 43 (67.5%) and 31 of 44 (71%) biopsies were normal, respectively. Two of 44 had chronic allograft hepatitis at 5 years. Two of 43 and 1 of 44 had isolated fibrosis, 3 of 43 and 3 of 44 steatosis, and 3 of 43 and 4 of 44 acute rejection at 1 and 5 years, respectively. Other findings included predominantly biliary changes (6/43 & 3/44 at 1 and 5 years, respectively). Tacrolimus levels at 5 years were slightly higher than anticipated (median trough level 5.8 μg/L). With an immunosuppressive regimen of tacrolimus and low-dose steroids for 1 year followed by tacrolimus monotherapy thereafter, the majority of PLB were normal and no progressive changes were observed at 5 years. Compared to other LT programs, we have lower rates of chronic allograft hepatitis, steatosis, and fibrosis at 5 years. However, the tacrolimus levels at 5 years were higher than planned and this may have played a role. Further evaluation is also required to determine the potential long-term adverse effects of corticosteroid use on linear growth and bone mineral density.

De novo aortopathy and cardiovascular outcomes in paediatric liver transplant recipients

With the increase in long-term survival of post-transplant children, there is a paradigm shift in the emphasis of post-transplant care. We describe de novo cardiovascular abnormalities, which occurred in otherwise asymptomatic paediatric liver transplant recipients, who received liver allografts between 1991 and 2014 at the National University Hospital, Singapore, detected during routine post-transplant monitoring. A total of 96 paediatric liver transplants were performed in 90 children. After transplant, 7/90 (7.8%) recipients were identified with new-onset aortopathy. Glycogen storage disease type I (42.9% versus 2.4%; p<0.001) and recipient Epstein-Barr virus seropositivity (85.7 versus 31.0%, p=0.004) were significant risk factors for aortopathy on univariate analysis. On multivariate analysis, only glycogen storage disease type I remained as the significant risk factor (odds ratio 51.3 [95% confidence intervals: 1.1-2498.1, p=0.047]). Liver transplant is a double-edged sword that reverses certain cardiopulmonary complications of end-stage liver disease but may induce de novo structural cardiac injury in the form of aortic dilation.

Growth, body composition, and bone density following pediatric liver transplantation

Patients transplanted for cholestatic liver disease are often significantly fat-soluble vitamin deficient and malnourished pretransplant, with significant corticosteroid exposure post-transplant, with increasing evidence of obesity and metabolic syndrome post-LT. Our study aimed to assess growth, body composition, and BMD in patients post-pediatric LT. Body composition and bone densitometry scans were performed on 21 patients. Pre- and post-transplant anthropometric data were analyzed. Bone health was assessed using serum ALP, calcium, phosphate, and procollagen-1-N-peptide levels. Median ages at transplant and at this assessment were 2.7 and 10.6 years, respectively. Physiological markers of bone health, median z-scores for total body, and lumbar spine aBMD were normal. Bone area was normal for height and BMAD at L3 was normal for age, indicating, respectively, normal cortical and trabecular bone accrual. Median z-scores for weight, height, and BMI were 0.6, -0.9, 1.8 and 0.6, 0.1, 0.8 pre- and post-transplant, respectively. Total body fat percentages measured on 21 body composition scans revealed 2 underweight, 7 normal, 6 overweight, and 6 obese. Bone mass is preserved following pediatric LT with good catch-up height. About 52% of patients were either overweight/obese post-transplant, potentially placing them at an increased risk of metabolic syndrome and its sequelae in later life. BMI alone is a poor indicator of nutritional status post-transplant.

De Novo Malignancy Following Adult-to-Adult Living Donor Liver Transplantation Focusing on Posttransplantation Lymphoproliferative Disorder

OBJECTIVE

In patients with living donor liver transplantation (LDLT), late-onset complications sometimes develop because of long-term use of immunosuppressive drugs. One of the immunosuppressive drug-related complications is de novo malignancies resulting in reduced survival.

PATIENTS AND METHODS

Among 153 patients undergoing LDLT, we retrospectively reviewed the medical records of 97 adult recipients (February 2002 to May 2017), who had been followed-up at our hospital for more than one year after LDLT. The median age was 52 years old (20-70) and the median observational period was 6.9 years (2.4-15.3).

RESULTS

De novo malignancy after adult LDLT developed in 11.3% (11/97) of patients, including posttransplantation lymphoproliferative disorder (PTLD) (n = 4) (2 in the brain and 2 in abdominal lymph nodes), lung cancer (n = 1), pancreatic cancer (n = 1), gastric cancer (n = 1), laryngeal cancer (n = 1), lower gingival cancer (n = 1), bladder cancer (n = 1), and melanoma (n = 1). Age at cancer diagnosis ranged from 36 to 70 years old with an average age of 61 years. The interval from LDLT to cancer diagnosis was 8.3 years (3.9-12.2). Four patients (36.6%) including PTLD (n = 2), lung cancer (n = 1), and pancreatic cancer (n = 1) died of cancer and all of them were diagnosed with cancer within 10 years after LDLT. Six patients were diagnosed with cancer more than 10 years after LDLT and all of them survived after treatment of cancer.

CONCLUSION

De novo malignancy was found in 11.3% of LDLT patients, and more than half of this population subset developed tumors 10 years after LDLT. Long-term close follow-up should be performed by taking any kinds of de novo malignancy into consideration.

Tolerance after liver transplantation: Where are we?

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.

Disparities in Waitlist and Posttransplantation Outcomes in Liver Transplant Registrants and Recipients Aged 18 to 24 Years: Analysis of the UNOS Database

BACKGROUND

We evaluated liver transplantation waitlist and posttransplantation outcomes in those aged 18 to 24 years compared with both younger (0-17 years) and older (25-34 years) registrants and recipients.

METHODS

Using national data from the United Network for Organ Sharing, competing risk, Cox regression and Kaplan-Meier analyses were performed on first-time liver transplant registrants (n = 13 979) and recipients (n = 8718) ages 0 to 34 years between 2002 and 2015.

RESULTS

Nonstatus 1A registrants, registrants aged 0 to 17 and 25 to 34 years were less likely to experience dropout from the waiting list compared with those aged 18 to 24 years (adjusted hazard ratio, 0-5 years = 0.36; 6-11 = 0.29; 12-17 = 0.48; 18-24 = 1.00; 25-34 = 0.82). Although there was no difference in risk of graft failure across all age groups, both younger and older age groups had significantly lower risk of posttransplant mortality compared with those aged 18 to 24 years (adjusted hazard ratio, for 0-5 years = 0.53, 6-11 = 0.48, 12-17 = 0.70, 18-24 = 1.00, 25-34 = 0.77). This may be related to lower likelihood of retransplantation after graft failure in those aged 18 to 24 years.

CONCLUSIONS

This national registry study demonstrates for the first time poorer waitlist and postliver transplant outcomes in young adults ages 18 to 24 years at the time of listing and transplantation compared to older and younger age groups. Given the potential survival benefit in transplanting young adults and the shortage of solid organs for transplant, future studies are critical to identify and target modifiable risk factors to improve waitlist and long-term posttransplant outcomes in 18- to 24-year-old registrants and recipients.

Early and Late Factors Impacting Patient and Graft Outcome in Pediatric Liver Transplantation: Summary of an ESPGHAN Monothematic Conference

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.