Pediatric Solid Organ Transplant Recipients Research Articles

Incidence of cancer after paediatric solid organ transplant recipients: A Scoping Review

Background: To investigate the incidence of post-transplant malignancies in paediatric recipients of solid organ transplants. Materials and Methods: We searched MEDLINE, Scopus and Web of Science up to January 2025 for observational studies reporting on cancer incidence in children who underwent solid organ transplantation (SOT). Data extraction and quality assessment were performed by two independent reviewers. Data on incidence rates, types of malignancies, and patient demographics were extracted and analysed. Results: Sixteen studies with a total of 26,310 paediatric transplant recipients were included. The cumulative incidence of cancer after kidney transplantation ranged from 10.2% at 15 years to 27% at 25 years. For liver transplantation, the incidence was 22% at 25 years, with a range from 3.4% to 7.1% incidence of post-transplant lymphoproliferative disorders (PTLD). Following heart transplantation, the incidence was 30.5% at 10 years. Conclusions: Paediatric solid organ transplant recipients face a significant risk of developing cancer, particularly PTLD. Regular monitoring and early intervention are essential for improving long-term outcomes.

P-616. Sociodemographic and Clinical Factors Affecting Vaccination after Pediatric Solid Organ Transplantation at Duke University

Abstract Background Pediatric solid organ transplant (SOT) recipients are at increased risk for vaccine preventable illnesses (VPI). They frequently receive vaccines after transplantation when immunosuppressive medications and cytopenias may impact their immune response to routine childhood vaccines. Current guidelines recommend monitoring vaccine-specific serologies to ensure optimal vaccine responses and to guide the need for repeat doses. Methods In this single-center retrospective cohort study, a multivariate logistic regression model was used to determine the sociodemographic and clinical factors associated with delays in starting post-transplant vaccines and adherence to post-vaccine serologic monitoring among 199 pediatric patients who received a SOT at Duke University between 2014-2023. The prevalence of cytopenias at the time of post-transplant vaccination was also described. Results Out of 150 children eligible for post-transplant vaccines (Table1), 48 (32%) failed to start catch-up vaccines within 2 years of transplantation. Older children (OR=0.877, 0.83-0.927) and children with private insurance (OR=0.458, 0.211-0.993) had significantly decreased odds of early catch-up vaccines (Table 2). Hepatitis B serologies were obtained in 23% of patients after post-transplant vaccination, but titers against the remaining non-live childhood vaccines were only obtained in 1-8% of children (Table 3). Approximately 53% of all children had neutropenia or lymphopenia (less than 1500 x 10^6 cells/L) at the time of post-transplant vaccination, with heart and intestinal/multi-visceral transplant recipients having the highest rates at ∼75% (Table 4). Conclusion These findings identify pediatric SOT recipients most at risk for delayed post-transplant vaccines. The associations between vaccine delay and private insurance and older age warrant further investigation. The extremely low rates of vaccine-specific serologic monitoring and the high prevalence of cytopenias at the time of vaccination raise concerns that pediatric SOT recipients are insufficiently protected from VPI. Future work will determine the impact of cytopenias on vaccine response and will address inequities in vaccination among pediatric SOT recipients. Disclosures All Authors: No reported disclosures

P-2070. SARS-CoV-2 Vaccination Rates Among a Cohort of Pediatric Solid Organ Transplant Recipients

Abstract Background SARS-CoV-2 vaccination has been shown to prevent severe disease and subsequent secondary infections in immunocompromised patients. This study assessed the rate of SARS-CoV-2 vaccinations among pediatric solid organ transplant (SOT) recipients at a single transplant center.Figure 1.SARS-CoV-2 vaccination status among pediatric solid organ transplant recipients for all ages and by age group. Methods We retrospectively reviewed medical records of pediatric recipients of heart, kidney, and liver transplants at Mayo Clinic, Rochester, MN between January 2011 and December 2023. All SARS-CoV-2 vaccine doses administered on or before April 1, 2024 were recorded. Up-to-date (UTD) status was based on current CDC recommendations for immunocompromised patients for each age group. Deceased patients, those no longer following at Mayo Clinic and whose vaccine records were unavailable were excluded. We also assessed whether patients had been seen by an ID physician in the year prior to collection stop date. Results The study included 136 patients: 48 kidney, 58 heart and 30 liver transplant recipients; 52.9% were male. Two patients subsequently received organs of a different type. Mean age was 16.1 years. Since authorization in 2020, 90 patients (66.2%) received at least one SARS-CoV-2 vaccine. This varied by age group, with 72.8% of > =12 year olds, 40.0% of 5-11 year olds and 62.5% of under 5 year olds (p = 0.007 [Figure 1]). Seventy-three patients (53.7%) completed at least three doses. Based on current recommendations that include the 2023-2024 formulation, 30 patients (22.0%) were UTD. This did not differ between age groups (p = 0.717) or by transplanted organ type (p = 0.21). Patients that saw ID were significantly more likely to be UTD (p = 0.001). Among partially immunized patients, 95% (n = 57) needed one additional dose to be UTD. Conclusion Despite simplified guidelines with fewer doses needed, a third of pediatric SOT recipients remain unvaccinated against SARS-CoV-2 and only 22% are UTD based on current recommendations. The proportion of unvaccinated patients was highest in the 5-11 year old age group and lowest in the oldest. Those that recently saw ID were significantly more likely to be UTD. Our data suggest that continued care provided by ID physicians may increase vaccine uptake, but reasons for undervaccination and strategies to counteract this should be further explored within this vulnerable population. Disclosures All Authors: No reported disclosures

P-1161. Bacterial Bloodstream Infections in Pediatric Solid Organ Transplant Recipients within One Year of Transplant

Abstract Background Bacterial bloodstream infections (BSI) are a major cause of morbidity in immunosuppressed children, yet data are limited for pediatric solid organ transplant recipients (SOT). Prior studies have found varying rates of BSI in the first 2 years after pediatric transplant. This single center study investigated the incidence, risk factors and outcomes of pediatric SOT recipients who experienced a BSI within 1 year of transplantation.Table 1.Patient demographics Methods Retrospective single-center study of pediatric heart, liver, or kidney transplant recipients undergoing their first transplant at Lurie Children’s between January 2010 and December 2023. The primary outcome measure was bacterial bloodstream infection (BSI) within one year of SOT (minimum follow-up three months).Table 2.Results for primary outcome Results A total of 582 patients under age 18 received a first SOT between January 1, 2010 and December 31, 2023 (Table 1). Overall incidence of BSI within one year of SOT was 8.6%. Rates were significantly higher in liver recipients (13.6%) than heart (7.4%) and kidney recipients (5.5%; P=0.02). Incidence was highest in patients transplanted between 1 and 5 years of age (15.7%) than in other age ranges (Table 2; P= 0.02). Among those with BSI, the median time to first episode after transplant was 20.5 days (IQR 11.3, 98.5; Table 3). The most common identified infectious source was a central venous catheter (Table 4), with 39 of the 49 episodes occurring while a central venous catheter was in place. The most common organisms identified were Klebsiella pneumoniae (8 patients), Staphylococcus epidermidis (7 patients), and Enterobacter cloacae (6 patients, 2 of whom had polymicrobial bacteremia). Overall incidence dropped significantly over the time frame analyzed, comparing those transplanted between 2010-14 (11.9%), between 2015-19 (8.9%), and 2020-2023 (4.3%); P=0.02.Table 3.Median time to first BSI after SOT Conclusion BSI within the first year after SOT is common in children, occurring at rates comparable to published data in adults. Children under 5 years of age had the highest rate, and presence of a central venous catheter was common during initial episodes. Further investigation is needed to identify more detailed risk factors associated with BSI in children receiving solid organ transplant, prevention strategies, and reasons contributing to the drop is BSI rates over time.Table 4.Organisms identified and source of infection Disclosures Larry K. Kociolek, MD, MSCI, Merck: Grant/Research Support William J. Muller, MD, Ansun Biopharma: Grant/Research Support|Astellas Pharma: Advisor/Consultant|Astellas Pharma: Grant/Research Support|AstraZeneca: Advisor/Consultant|AstraZeneca: Grant/Research Support|DiaSorin: Advisor/Consultant|DiaSorin: Honoraria|Eli Lilly and Company: Grant/Research Support|Enanta Pharmaceuticals: Advisor/Consultant|Enanta Pharmaceuticals: Grant/Research Support|F. Hoffmann-LaRoche Ltd (Roche): Grant/Research Support|Finley Law Firm, P.C.: Advisor/Consultant|Gilead Sciences: Grant/Research Support|Melinta Therapeutics, Inc.: Grant/Research Support|Merck Sharpe & Dohme: Grant/Research Support|Moderna: Grant/Research Support|Nabriva Therapeutics, plc: Grant/Research Support|Paratek Pharmaceuticals, Inc.: Grant/Research Support|Pfizer: Grant/Research Support|ProventionBio: Advisor/Consultant|Sanofi: Advisor/Consultant|Sanofi: Honoraria|Tetraphase Pharmaceuticals, Inc.: Grant/Research Support

P-2335. Comparison of Adverse Drug Effects and Incidence of CMV Infection Between Different Dosing Regimens for Valganciclovir in the Pediatric Solid Organ Transplant Population

Abstract Background Valganciclovir has become widely used for the prevention of (CMV) infection in solid organ transplant (SOT) patients in both adult and pediatric populations. However, there is no consensus about the optimum dosing regimen in pediatric patients. Our study aims to compare the frequency of side effects and rate of CMV between two commonly used dosing regimens. Methods In August 2020, as part of quality improvement initiative our internal SOT guideline for Valganciclovir dosing switched from weight-based (15-25 mg/kg/dose) to the manufacturer recommended dosing based on body surface area and estimated glomerular filtration rate (BSA/eGFR). We retrospectively reviewed medical records of pediatric patients (0-20 years) who underwent SOT (including liver, heart, and kidney) from 2/2015 to 2/2024. The collected data include age, transplanted organ, occurrence of abnormal liver functions (LFT) and neutropenia, and number of episodes of CMV infection during prophylaxis and 6 months post-prophylaxis. Moderate and severe neutropenia were defined as absolute neutrophil count (ANC) 500-1000 and ANC < 500, respectively. Results 116 pediatric SOT recipients were distributed almost equally between heart (32%), kidney (34%), and liver (34%) transplants. 28/116 (24%) received BSA/eGFR-based dosing. The median duration of prophylaxis was 3.9 months (IQR 2.9-6). The frequency of abnormal LFTs were similar in both dosing groups (64% in the BSA/eGFR group vs 65% in the weight-based group). Moderate neutropenia was more frequent in the BSA/eGFR group (36%) compared to the weight-based group (17%) and severe neutropenia occurred in 11% and 18%, respectively. However, these differences were not significantly different(P=0.11). CMV infection occurred in 27% of total population of patients with no significant difference in breakthrough infection on prophylaxis between the two groups (4% vs 10%, P=0.45). Conclusion In pediatric SOT recipients, valganciclovir prophylaxis dosed based on BSA/eGFR or weight had a similar side effect profile for liver toxicity and severe neutropenia. In addition, there was no significant difference in the occurrence of CMV infections between the dosing regimens. Disclosures All Authors: No reported disclosures

P-2278. CMV Viremia and Disease in Pediatric Liver Transplant Patients: a Multi-national Systematic Review and Meta-analysis

Abstract Background Cytomegalovirus (CMV) viremia (Defined as a single detectable CMV RNA PCR) and disease (defined as CMV viremia with compatible systemic and/or localized signs and symptoms) remain a leading cause for mortality and morbidity in the pediatric solid organ transplant recipient. This systemic review aims at pooling data from the leading pediatric transplant institutions globally to identify the overall incidence of and risk factors associated with CMV viremia and/or disease in pediatric liver transplant recipients. PRISMA flow diagram Methods A systemic review of Pubmed and OVID databases was conducted since the inception to 01 April 2024. 24 articles were included from the USA, UK, South Africa, India, Japan, Finland, Canada, Turkey, Mexico, Thailand, Greece, Israel and Australia. A total of 1964 liver transplants were included. Median age was 50 months with 47.8% males. Data related to demographics, incidence, donor and recipient CMV serological classification (Donor (D) and Recipient (R)) and risk factors for CMV viremia/disease were extracted from the articles and subsequently analysed. This review was registered in Prospero: CRD42023477476 Results The Incidence of CMV viremia and disease in pediatric liver transplant patients in this review were 34% and 8.4% respectively, with statistically significant higher risk in the CMV D+/R+ category compared to other D/R serologic groups (P value < 0.05). , Additional risk factors identified for CMV viremia/disease included younger age, biliary atresia, high steroid doses, and rejection attacks. Conclusion This meta-analysis highlights that CMV viremia and disease post-liver transplantation are significant health concerns in pediatric populations. Identifying high risk populations for targeted CMV monitoring and potentially preemptive therapy to mitigate CMV-associated morbidity and mortality is a critical cornerstone of pediatric transplant medicine. Further studies are warranted to explore additional risk factors and to refine prevention and treatment strategies for CMV in pediatric transplant recipients. Disclosures All Authors: No reported disclosures

Prevention of Infections Among Pediatric Solid Organ Transplant Recipients With Asplenia or Hyposplenism.

Pediatric solid organ transplant (SOT) recipients with splenic dysfunction are at increased risk for infections, and tailored guidance on the management of asplenia/hyposplenism among SOT recipients is often lacking. The purpose of this article is to provide practice recommendations via a frequently asked questions (FAQs) format that focuses on three main domains: the identification of asplenia/hyposplenism among SOT recipients/candidates, prophylactic strategies for mitigating the risk of invasive disease associated with splenic dysfunction in the context of transplantation, and the provision of appropriate patient counseling on the risks associated with asplenia/hyposplenism. Answers to the FAQs are based on international expert opinion informed by practices for managing splenic dysfunction and associated data in other populations with asplenia. Gaps in the existing literature and relevant research aims are emphasized.

New Immunosuppressants in Pediatric Kidney Transplantation: What's in the Pipeline for Kids?

The 1- and 5-year patient and graft survival rates of pediatric kidney transplant recipients have improved considerably in recent years. Regardless of early success, kidney transplantation is challenged by suboptimal long-term allograft and patient survival. Many kidney transplants are lost due to immune (rejection) and nonimmune allograft injuries, and patient survival is limited from cardiovascular disease, infection, and malignancy. Many of these co-morbidities are due to side effects of the currently available immunosuppressive drugs, especially calcineurin inhibitors and glucocorticoids, which are associated with long-term toxicity. Hence, there is an urgent need to develop new, more specific and less toxic immunosuppressive drugs. Unfortunately, there have also been no new drug approvals for adult kidney transplant recipients since belatacept in 2012, leaving the immunosuppressive drug armamentarium unchanged for more than 20 years. As a consequence of the lack of innovation in adult kidney transplant recipients, the pipeline of novel immunosuppressive agents for pediatric solid organ transplant recipients is also limited. The most promising agent in the near future, at least for adolescent patients, appears to be belatacept, despite its many limitations. In this review article, we report on three areas that appear to be the most relevant topics at this time: (i) extended-release tacrolimus, (ii) costimulation blockade with belatacept, and (iii) treatment of antibody-mediated rejection. Improved synergies between the pharmaceutical industry and the transplant community are needed to achieve the ultimate goal of improving long-term outcomes in pediatric kidney transplantation.

Species distribution and antifungal susceptibility patterns of Candida involvement in pediatric solid organ transplant recipients: A cross-sectional study from a single transplant center

The epidemiology and resistance patterns of Candida infections in pediatric kidney/liver recipients has not been well characterized, recently. In this study, all patients ≤ 18 years old who underwent liver/kidney transplant surgery between September 2021 and 2022 were included. Species identification of isolates recovered from clinical specimens was performed by DNA-sequencing method following amplification of the ITS1-5.8S-ITS2 regions. Antifungal susceptibility patterns of isolates were performed using the micro broth dilution method documented by Clinical & Laboratory Standards Institute (CLSI) guidelines. Of the 117 pediatric recipients enrolled, 16 recipients (13.7 %) had at least one positive Candida culture. Candidemia was detected in 5/89 (5.6 %) of liver and 1/28 (3.6 %) of kidney transplant recipients. Invasive candidiasis was observed in 6/89 (6.7 %) of liver and 2/28 (7.1 %) of kidney transplant recipients. The predominant species was Candida (C.) albicans recovered from 12 of 16 recipients (75 %). In addition to the Pichia kudriavzevii species with inherent resistance to fluconazole, one of C. albicans isolates and one C. tropicalis isolate were also identified as fluconazole-resistant (3/29:10.3 %). Moreover, our findings revealed 13.8 % and 6.8 % resistance to itraconazole and voriconazole, respectively. All Candida spp. were susceptible to caspofungin. Collectively, this study provides valuable insights into the epidemiology and resistance patterns of Candida infections in pediatric kidney and liver recipients. The study also highlights the emergence of fluconazole-resistant strains, which has significant implications for antifungal stewardship efforts in pediatric transplant populations.

Regional Variations and Risk Factors for Post-Transplant Lymphoproliferative Disorder in Pediatric Solid Organ Transplant Recipients: A Nationwide Study

Regional Variations and Risk Factors for Post-Transplant Lymphoproliferative Disorder in Pediatric Solid Organ Transplant Recipients: A Nationwide Study

Multicenter Analysis of Valganciclovir Prophylaxis in Pediatric Solid Organ Transplant Recipients

Abstract Background Valganciclovir (VGCV) prophylaxis against cytomegalovirus (CMV) infection and disease has provided an important advance in the management of pediatric solid organ transplantation (SOT) recipients over the past two decades. However, there remain significant questions regarding its relative safety and efficacy, optimal dosing strategies, and toxicities including neutropenia and lymphopenia. We performed a multi-center retrospective study of children post SOT who were to receive at least 3 months of valganciclovir. The primary outcomes were CMV DNAemia while receiving prophylaxis (breakthrough) and post-prophylaxis CMV DNAemia within the first year. Methods The study population included patients ≤ 20 years of age at the time of their first transplant between January 2016 and December 2019 from 8 US centers in PIDTRAN Network. Data for each patient was extracted from the electronic medical record and entered into a REDcap database hosted by St. Jude Children’s Research Hospital. Variables analyzed included demographics, donor/recipient CMV serostatus, immunosuppression, trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis use, rejection, other viral or bacterial infections and one-year survival. Statistics were performed using STATA software for univariate and multivariate models; p-value< 0.05 was considered statistically significant. Results 749 pediatric SOT patients were enrolled over the 3-year study period. Breakthrough DNAemia occurred in 85 (11.4%) patients and post-prophylaxis CMV DNAemia was documented in an additional 46 (6.9%) patients. CMV disease occurred in only 30 patients (4%). In univariate analysis, there were no differences in age, sex, race/ethnicity, or immunosuppression comparing those who experienced breakthrough or post-prophylaxis CMV DNAemia compared to those without CMV DNAemia, but there were differences based on transplanted organ (p< 0.001, liver and lung > heart > kidney) and CMV risk status (high and intermediate) (p<0.001). Neutropenia (p<0.001) and lymphopenia (p=0.003) as well as VGCV discontinuation or dose reduction for perceived toxicity (p<0.001) were associated with breakthrough CMV infection. Bacteremia (p=0.001), EBV viremia (p=0.02), and adenovirus viremia (p=0.002) were also documented more in those with breakthrough compared to those who never had CMV DNAemia. In an adjusted Cox regression hazard model using all significant univariate variables, transplanted organ, CMV risk status, toxicity related VGCV modification (p=0.005), and bacteremia (p=0.01) were independently associated with breakthrough CMV infection. Breakthrough CMV was also associated with rejection (p=0.01) in a separate logistic multivariable model. Both liver (p<0.001) and heart transplant (p<0.001) patients had a greater risk of rejection over the first year of transplantation, but only liver transplant patients had a greater risk of rejection with breakthrough CMV infection (p=0.004). Post prophylaxis CMV DNAemia was associated with mortality at 1 year in the univariate analysis in the full cohort (p=0.001). Conclusion Rates of CMV disease when using valganciclovir prophylaxis were low in this large, multicenter cohort of pediatric SOT recipients. However, breakthrough CMV infection continues to be a problem in intermediate- and high-risk CMV patients and is associated with significant morbidity and rejection, particularly in the liver transplant population. Alternative approaches to prevent breakthrough and post-prophylaxis CMV and with a better safety profile should be studied in pediatric SOT patients.

Adolescent and Young Adult Development in Transplant Recipients.

Solid organ transplantation (SOT) is the gold standard of therapy for individuals with end-organ dysfunction. Improved survival outcomes after SOT can help adolescent and young adult (AYA) recipients lead long and healthy life. However, successful SOT during adolescence and young adulthood is often complicated by the innate developmental challenges of this age group. The psychosocial tasks of adolescence include identity development, autonomous decision-making, establishing social networks, educational and vocational preparation, and navigating romantic relationships. These goals may be amplified or delayed for pediatric SOT recipients. Adolescence is also marked by rapid physical changes in linear growth and the development of secondary sexual characteristics. Yet AYA may experience physical and pubertal delays related to transplantation, as well as exaggerated body image dissatisfaction due to medication side effects. Strict adherence to medication and post-transplant regimens may interfere with adolescents' desire for normalcy and fitting in with peers. Healthcare providers should be aware that AYA value education and self-empowerment in transplant care. Transplant success needs to be defined by both medical and psychosocial outcomes, particularly when it relates to the vulnerable AYA population. Fortunately, investment from the patient, family, and care team can aid in transplant recovery and success. This article will identify the developmental challenges faced by AYA undergoing solid organ transplantation as well as strategies to engage positive outcomes.

Posttransplant Lymphoproliferative Disorder in Pediatric Solid-Organ Transplant Recipients: A 7-Year Single-Center Analysis.

Posttransplant lymphoproliferative disorder is a consequential complication following solid-organ transplant, particularly associated with the Epstein-Barr virus. We studied a single center's cases of pediatric posttransplant lymphoproliferative disorder for a 7-year period and focused on incidence rates, anatomic sites involved, and correlation with clinical outcomes. We explored clinical features and treatment outcomes in patients with pediatric posttransplant lymphoproliferative disorder, with emphasis on patient survival and associated clinical ramifications. This was a retrospective analysis of medical records from pediatric solid-organ transplant recipients (liver or kidney) at Baskent University Ankara Hospital Organ Transplantation Center between January 1, 2017, and January 1, 2024, approved by the Institutional Review Board (KA24/63). We identified cases based on pathology-confirmed persistent lymphadenopathy or tumorous lesions. Patient categorization distinguished between malignant and benign groups. Early posttransplant lymphoproliferative disorder was defined within the initial year after transplant. Epstein?Barr virus association was determined through in situ hybridization, and patient characteristics were reviewed comprehensively. In 7 years, 10 pediatric patients (9 liver transplants, 1 kidney transplant) were diagnosed with posttransplant lymphoproliferative disorder, with an incidence of 8.7% for pediatric liver transplants. Mean age at diagnosis was 46.4 months, and mean time from transplant to diagnosis was 21.2 months. The most common complaints at diagnosis included fever, lymphadenopathy, hepatosplenomegaly, dyspnea, and diarrhea. Treatment modalities included rituximab, immunosuppression reduction, intravenous immunoglobulin therapy, and chemotherapy (NHL Berlin-Frankfurt-Münster 90 protocols). All patients achieved remission (mean follow-up, 22.9 mo). Early diagnosis of posttransplant lymphoproliferative disorder is important, and rituximab with immunosuppression reduction is effective to achieve complete remission, particularly in early polymorphic cases. Despite challenges, all patients achieved remission, signaling improved outcomes in pediatric posttransplant lymphoproliferative disorder. Active monitoring of Epstein?Barr virus infection may further reduce posttransplant lymphoproliferative disorder complications in pediatric solid-organ transplant; hence, early diagnosis is crucial.

Prevalence and Consequences of Glomerular Hyperfiltration (HF) in Pediatric Solid-Organ Transplant (SOT) Recipients

Prevalence and Consequences of Glomerular Hyperfiltration (HF) in Pediatric Solid-Organ Transplant (SOT) Recipients

Risk Factors of Post-Traumatic Stress in Pediatric Solid Organ Transplant Recipients.

Life with end-stage organ failure is accompanied by an accumulation of traumatic medical or surgical experiences. Despite recovery after solid organ transplantation (SOT), many children and adolescents develop post-traumatic stress symptoms (PTSS). PTSS remain underappreciated as a major comorbidity in SOT programs, despite their association with decreased quality of life. We conducted a retrospective, cross-sectional study of 86 pediatric SOT recipients (17 heart, 44 kidney, and 25 liver) to evaluate potential determinants of PTSS. Trauma symptoms were measured by the Child Trauma Screening Questionnaire (CTSQ). Demographic, baseline, and contemporaneous factors were tested for independent association with CTSQ scores. The median post-transplant CTSQ score was 2 (IQR 1-4), and 22% were identified as high risk (score ≥5) for PTSD. Higher CTSQ scores were independently associated with the number of ICU days within the previous 12 months, the number of medications (complexity), and involvement with foster care in the primary model (R2 [adj.] = 0.26). The addition of the Family Impact Module improved the overall model (R2 [adj.] = 0.33), wherein higher family functioning was independently associated with lower CTSQ scores. An exploratory analysis of pre-transplant patients (n = 34) found a median pre-transplant CTSQ of 2 (IQR 1-6), suggesting that PTSS are onset before transplant and persist afterward. PTSS are highly prevalent in the SOT population. Risk factors include recent adverse medical experiences and complexity, whereas family stability may be protective. Additional research is needed to improve early ascertainment and support for patients at high risk of developing PTSS throughout their transplant journey.

P.491: Post transplant lymphoproliferative disorder in pediatric solid organ transplant recipients: A seven-year single-center analysis.

P.491: Post transplant lymphoproliferative disorder in pediatric solid organ transplant recipients: A seven-year single-center analysis.

Vaccinations in Paediatric Solid Organ Transplant Candidates and Recipients.

Solid organ transplant (SOT) candidates and recipients are a fragile population, in which the presence of a pre-transplant disease leading to organ insufficiency and the post-transplant immunosuppressive treatment expose them to an increased risk of infectious diseases. The best intervention to guarantee efficient prevention of infections, with optimal cost-benefit ratio, is represented by vaccination programs; however, the response to vaccines needs that the immune system maintains a good function. This is even more relevant at paediatric age, when specific immunological conditions make transplant candidates and recipients particularly vulnerable. Paediatric patients may be naïve to most infections and may have incomplete immunization status at the time of transplant listing due to their age. Moreover, the unaccomplished development of a mature immune system and the immunosuppressive regimen adopted after transplant might affect the efficacy of post-transplant vaccinations. Therefore, every effort should be made to obtain the widest vaccination coverage before the transplantation, whenever possible. This review reports the most relevant literature, providing information on the current approach to the vaccinations in paediatric SOT candidates and recipients.

An 8-Week Virtual Exercise Training Program for Pediatric Solid Organ Transplant Recipients.

Musculoskeletal strength can be impaired in pediatric solid organ transplant recipients. Exercise training programs can be beneficial but in-person delivery can be challenging; virtual exercise programs can alleviate some of these challenges. This feasibility study aimed to deliver an 8-week virtual exercise program in pediatric solid organ transplant recipients. Program delivery occurred 3 times per week for 30minutes. An exercise stress test was completed prior to program start. The Bruininks-Oseretsky Test of Motor Proficiency strength subtest and self-report surveys were used to assess musculoskeletal strength, quality of life, fatigue, and physical activity. Contact was maintained through a text messaging platform. Z scores were calculated using standardized normative data. Medians (interquartile range) are reported for all other data. Eleven participants completed the program (2 liver, 5 kidney, 4 heart; 58% females; median age = 11.5 [10.3-13.8]y). Six participants attended ≥60% of classes, 5 participants attended <50% of classes. After 8weeks, strength scores improved (Z score, Pre: -1.0 [-1.65 to -0.60] to Post: -0.2 [-1.30 to 0.40]; P = .007) with no change in other outcome measures. The virtual exercise program was delivered without technical issues and received positive participant feedback. Engagement and costs need to be considered.

The Crucial Role of Empowerment in Engaging Adolescents and Young Adults for Independence: Essential Strategies and Skills for a Successful Transition.

An increasing number of pediatric solid organ transplant (SOT) recipients are surviving into adolescence and young adulthood. The transition from pediatric to adult-oriented care occurs during a unique and vulnerable period. Presented here is a structured approach to healthcare transition (HCT) for adolescent and young adult SOT recipients aimed at optimizing independence in order to assist young patients with adherence, self-management, and improved quality of life. Close attention must be paid to neurocognitive development, mental well-being, and social determinants of health. These efforts require a multidisciplinary team approach as well as collaboration between pediatric and adult providers in order to achieve these goals and patient longevity.

Varicella-Zoster Virus Pretransplant Vaccination and Posttransplant Infections Among Pediatric Solid Organ Recipients in the Two-Dose Varicella Era: A Single-Center, Multi-Organ Retrospective Study.

Varicella-zoster virus (VZV) pretransplant immunization rates, exposures, and posttransplant disease are poorly characterized among pediatric solid organ transplant (SOT) recipients in the two-dose varicella vaccine era. A retrospective analysis of the electronic health records among children <18 years old who received SOT from January 1, 2011 through December 31, 2021, was performed at a single center to assess for missed pretransplant varicella vaccination opportunities, characterize VZV exposures, and describe posttransplant disease. Among 525 children, 444 were ≥6 months old (m.o.) at SOT with a documented VZV vaccine status. Eighty-five (19%) did not receive VZV Dose One; 30 out of 85 (35%) could have been immunized. Infants 6-11 m.o. accounted for 14 out of 30 (47%) missed opportunities. Among children ≥12 m.o. with documented Dose Two status (n = 383), 72 had missed vaccination opportunities; 57 out of 72 (79%) were children 1-4 years old. Most children had unclassifiable pre-SOT serostatus as varicella serology was either not obtained/documented (n = 171) or the possibility of passive antibodies was not excluded (n = 137). Of those with classified serology (n = 188), 69 were seroimmune. Forty-seven of 525 (9%) children had recorded VZV exposures; two developed varicella-neither had documented pre-SOT seroimmunity nor had received post-exposure prophylaxis. Nine additional children had medically attended disease: four primary varicella and five zoster. Of the 11 cases, 10 had cutaneous lesions without invasive disease; one had multi-dermatomal zoster with transaminitis. Seven (64%) received treatment exclusively outpatient. VZV exposure and disease still occur. Optimizing immunization among eligible candidates and ensuring patients have a defined VZV serostatus pretransplantation remain goals of care.