Epstein-Barr virus-associated risk factors for post-transplant lymphoproliferative disease in pediatric liver transplant recipients

Post-transplant lymphoproliferative disorder in pediatric liver transplant recipients: Experience from a South African transplant center

INTRODUCTION

Post-transplant lymphoproliferative disorder (PTLD) is a clinically heterogeneous potentially fatal complication of pediatric liver transplantation (PLT). We determined the prevalence, complications, and associated factors for PTLD in PLT recipients from Wits Donald Gordon Medical Centre, South Africa from January 2012 to August 2019.

METHODS

We performed a retrospective record review of 150 PLT recipients.

RESULTS

Histologically proven PTLD occurred in 17/150 PLT recipients (11.3%). Children with PTLD were significantly younger at transplant (17.9 vs. 32.7 months, p = 0.001) with a significantly higher prevalence of obstructive etiology (17/17 vs. 81/133, p = 0.001). Fifteen (88.2%) children with PTLD were Epstein-Barr virus (EBV) seronegative at transplant. High post-transplant EBV viral load at a threshold value of 4.8 log10 DNA copies/mL (sensitivity: 80.0% [95% confidence interval {CI}, 46.7%-100.0%]; specificity: 73.1% [95% CI 42.3%-93.3%; area under the curve {AUC} 75.8%]) and low post-transplant albumin levels at a threshold value of 21.5 g/L (sensitivity: 70.6% [95% CI, 41.2%-94.1%]; specificity: 85.7% [95% CI, 60.4%-94.5%; {AUC} 74.8%]) were associated with PTLD. The prevalence of cytomegalovirus (CMV) disease was significantly higher in children who developed PTLD versus non-PTLD (12/17 vs. 18/133; p < 0.001). CMV disease and the combination of post-transplant high EBV viral load and low albumin were independently associated with an increased risk of developing PTLD. Four (23.5%) children with PTLD died, however, survival was equivalent to non-PTLD PLT (p = 0.580).

CONCLUSION

The prevalence of PTLD in our cohort mirrors international cohorts, with mortality similar to non-PTLD PLT recipients.

Immune deficiency/dysregulation -associated lymphoproliferative disorders. Revised classification and management

Significant advances in the field of lymphoma have resulted in two recent classification proposals, the International Consensus Classification (ICC) and the 5th edition WHO. A few entities are categorized differently in the ICC compared to the WHO. Nowhere is this more apparent than the immunodeficiency lymphoproliferative disorders. The three previous versions of the WHO classification (3rd, 4th and revised 4th editions) and the ICC focused on four clinical settings in which these lesions arise for primary categorization. In contrast the 2023 WHO 5th edition includes pathologic characteristics including morphology and viral status, in addition to clinical setting, as important information for lesion classification. In addition, the 2023 WHO recognizes a broader number of clinical scenarios in which these lesions arise, including not only traditional types of immune deficiency but also immune dysregulation. With this classification it is hoped that new treatment strategies will be developed leading to better patient outcomes.

Balancing immunosuppression in pediatric liver transplantation: Playing the long game

The overarching goal in the care of pediatric liver transplant recipients is to optimize allograft and patient health. Balancing immunosuppression to maintain allograft health while avoiding medication side effects is essential for long-term survival and optimal quality of life in pediatric liver transplant recipients. Utilizing precision medicine to personalize immunosuppression, which includes minimization and withdrawal, is core to this effort. The unique anatomy and physiology of the liver make it more tolerant to immune-mediated injury and a more favorable organ for immunosuppression minimization and withdrawal. However, several challenges exist. Standard biochemical values and histologic features may not reliably predict allograft health after a reduction in immunosuppression. Additionally, biochemical values alone do not reliably identify which patients can successfully develop operational tolerance, as there may be occult allograft injury despite normal liver enzymes. Finally, the durability of tolerance after successful reduction in immunosuppression remains uncertain over time. Innovative tools show promise in circumventing these challenges, but more research is needed to determine actual clinical utility. While immunosuppression-free transplant may not be a current reality for most pediatric liver transplant recipients, strategies to safely minimize immunosuppression without compromising allograft health are within reach. Each liver allograft and recipient pair requires a different degree of immune modulation, and through a structured process of minimization and withdrawal, immunosuppression can indeed be tailored in a precise, personalized way to optimize outcomes. This review focuses on the progress that has been made to individualize immunosuppression in pediatric liver transplantation to ensure optimal allograft and recipient health.

The pathobiology of select adolescent young adult lymphomas

Lymphoid cancers are among the most frequent cancers diagnosed in adolescents and young adults (AYA), ranging from approximately 30%-35% of cancer diagnoses in adolescent patients (age 10-19) to approximately 10% in patients aged 30-39 years. Moreover, the specific distribution of lymphoid cancer types varies by age with substantial shifts in the subtype distributions between pediatric, AYA, adult, and older adult patients. Currently, biology studies specific to AYA lymphomas are rare and therefore insight into age-related pathogenesis is incomplete. This review focuses on the paradigmatic epidemiology and pathogenesis of select lymphomas, occurring in the AYA patient population. With the example of posttransplant lymphoproliferative disorders, nodular lymphocyte-predominant Hodgkin lymphoma, follicular lymphoma (incl. pediatric-type follicular lymphoma), and mediastinal lymphomas (incl. classic Hodgkin lymphoma, primary mediastinal large B cell lymphoma and mediastinal gray zone lymphoma), we here illustrate the current state-of-the-art in lymphoma classification, recent molecular insights including genomics, and translational opportunities. To improve outcome and quality of life, international collaboration in consortia dedicated to AYA lymphoma is needed to overcome challenges related to siloed biospecimens and data collections as well as to develop studies designed specifically for this unique population.

Post-transplant lymphoproliferative disorders (PTLD) in adolescents and young adults: A category in need of definition

Post-transplant lymphoproliferative disorders are a well-recognized complication of solid organ and stem cell transplantation. Much data has accumulated with respect to the pathobiology and clinical behavior of these lesions in the general post-transplant population as well as in the pediatric and adult age groups. However, information as to these lesions in the adolescent and young adult populations, which bridge the pediatric and adult groups, is limited. In this review, the focus is on this unique population of PTLD patients and their proliferations.

Update on Epidemiology and Outcomes of Infection in Pediatric Organ Transplant Recipients

Pediatric solid organ transplant (SOT) recipients are at risk for infection following transplantation. Data from adult SOT recipients are often used to guide prevention and treatment of infections associated with organ transplantation in children. This article highlights key recent pediatric SOT-specific publications for an array of infectious complications of organ transplantation. Attention is given to areas of need for future study.