Model-Informed Estimation of Acutely Decreased Tacrolimus Clearance and Subsequent Dose Individualization in a Pediatric Renal Transplant Patient With Posterior Reversible Encephalopathy Syndrome.

BACKGROUND: Considerable interpatient and interoccasion variability has been reported in tacrolimus pharmacokinetics (PK) in the pediatric renal transplant population. This study investigated tacrolimus PK in a 2-year-old post-renal transplant patient and a known CYP3A5 expresser who developed posterior reversible encephalopathy syndrome (PRES) and had significantly elevated tacrolimus blood concentrations during tacrolimus treatment. A model-informed PK assessment was performed to assist with precision dosing. Tacrolimus clearance was evaluated both before and after the development of PRES on post-transplant day (PTD) 26. METHODS: A retrospective chart review was conducted to gather dosing data and tacrolimus concentrations, as part of a clinical pharmacology consultation service. Individual PK parameters were estimated by Bayesian estimation using a published pediatric PK model. Oral clearance (CL/F) was estimated for 3 distinct periods-before CNS symptoms (PTD 25), during the PRES event (PTD 27-30), and after oral tacrolimus was restarted (PTD 93). RESULTS: Bayesian estimation showed an estimated CL/F of 15.0 L/h in the days preceding the PRES event, compared with a population mean of 16.3 L/h (95% confidence interval 14.9-17.7 L/h) for CYP3A5 expressers of the same age and weight. Samples collected on PTD 27-30 yielded an estimated CL/F of 3.6 L/h, a reduction of 76%, coinciding with clinical confirmation of PRES and therapy discontinuation. On PTD 93, an additional assessment showed a stable CL/F value of 14.5 L/h 1 month after reinitiating tacrolimus and was used to recommend a continued maintenance dose. CONCLUSIONS: This is the first report to demonstrate acutely decreased tacrolimus clearance in PRES, likely caused by the downregulation of metabolizing enzymes in response to inflammatory cytokines. The results suggest the ability of model-informed Bayesian estimation to characterize an acute decline in oral tacrolimus clearance after the development of PRES and the role that PK estimation may play in supporting dose selection and individualization.

Donor specific antibody surveillance among pediatric kidney transplant programs: A report from the improving renal outcome collaborative.

BACKGROUND: Kidney transplantation (KT) is the preferred treatment for children with end-stage kidney disease. Recent advances in immunosuppression and advances in donor specific antibody (DSA) testing have resulted in prolonged allograft survival; however, standardized approaches for surveillance DSA monitoring and management of de novo (dn) DSA are widely variable among pediatric KT programs. METHODS: Pediatric transplant nephrologists in the multi-center Improving Renal Outcomes Collaborative (IROC) participated in a voluntary, web-based survey between 2019 and 2020. Centers provided information pertaining to frequency and timing of routine DSA surveillance and theoretical management of dnDSA development in the setting of stable graft function. RESULTS: 29/30 IROC centers responded to the survey. Among the participating centers, screening for DSA occurs, on average, every 3 months for the first 12 months post-transplant. Antibody mean fluorescent intensity and trend most frequently directed changes in patient management. Increased creatinine above baseline was reported by all centers as an indication for DSA assessment outside of routine surveillance testing. 24/29 centers would continue to monitor DSA and/or intensify immunosuppression after detection of antibodies in the setting of stable graft function. In addition to enhanced monitoring, 10/29 centers reported performing an allograft biopsy upon detection of dnDSA, even in the setting of stable graft function. CONCLUSIONS: This descriptive report is the largest reported survey of pediatric transplant nephrologist practice patterns on this topic and provides a reference for monitoring dnDSA in the pediatric kidney transplant population.

Carfilzomib-based antibody mediated rejection therapy in pediatric kidney transplant recipients.

BACKGROUND: To date, the evidence for proteasome-inhibitor (PI) based antibody mediated rejection (AMR) therapy has been with the first-generation PI bortezomib. Results have demonstrated encouraging efficacy for early AMR with lesser efficacy for late AMR. Unfortunately, bortezomib is associated with dose-limiting adverse effects in some patients. We report use of the second generation proteosome inhibitor carfilzomib for AMR treatment in two pediatric patients with a kidney transplant. METHODS: The clinical data on two patients who experienced dose limiting toxicities from bortezomib were collected along with their short- and long-term outcomes. RESULTS: A two-year-old female with simultaneous AMR, multiple de novo DSAs (DR53 MFI 3900, DQ9 MFI 6600, DR15 2200, DR51 MFI 1900) and T-cell mediated rejection (TCMR) completed three carfilzomib cycles and experienced stage 1 acute kidney injury after the first two cycles. At 1 year follow up, all DSAs resolved, and her kidney function returned to baseline without recurrence. A 17-year-old female also developed AMR with multiple de novo DSAs (DQ5 MFI 9900, DQ6 MFI 9800, DQA*01 MFI 9900). She completed two carfilzomib cycles, which were associated with acute kidney injury. She had resolution of rejection on biopsy and decreased but persistent DSAs on follow-up. CONCLUSIONS: Carfilzomib treatment for bortezomib-refractory rejection and/or bortezomib toxicity may provide DSA elimination or reduction, but also appears to be associated with nephrotoxicity. Clinical development of carfilzomib for AMR will require a better understanding of efficacy and development of approaches to mitigate nephrotoxicity.

The learning health system for pediatric nephrology: building better systems to improve health.

Learning health systems (LHS) align science, informatics, incentives, and culture for continuous improvement and innovation. In this organizational system, best practices are seamlessly embedded in the delivery process, and new knowledge is captured as an integral byproduct of the care delivery experience aimed to transform clinical practice and improve patient outcomes. The objective of this review is to describe how building better health systems that integrate clinical care, improvement, and research as part of an LHS can improve care within pediatric nephrology. This review will provide real-world examples of how this system can be established in a single center and across multiple centers as learning health networks.

COVID-19 in pediatric kidney transplantation: a follow-up report of the Improving Renal Outcomes Collaborative.

BACKGROUND: We report follow-up data from an ongoing prospective cohort study of COVID-19 in pediatric kidney transplantation through the Improving Renal Outcomes Collaborative (IROC). METHODS: Patient-level data from the IROC registry were combined with testing, indication, and outcomes data collected to describe the epidemiology of COVID testing, treatment, and clinical outcomes; determine the incidence of a positive COVID-19 test; describe rates of COVID-19 testing; and assess for clinical predictors of a positive COVID-19 test. RESULTS: From September 2020 to February 2021, 21 centers that care for 2690 patients submitted data from 648 COVID-19 tests on 465 patients. Most patients required supportive care only and were treated as outpatients, 16% experienced inpatient care, and 5% experienced intensive care. Allograft complications were rare, with acute kidney injury most common (7%). There was 1 case of respiratory failure and 1 death attributed to COVID-19. Twelve centers that care for 1730 patients submitted complete testing data on 351 patients. The incidence of COVID-19 among patients at these centers was 4%, whereas the incidence among tested patients was 19%. Risk factors to predict a positive COVID-19 test included age > 12 years, symptoms consistent with COVID-19, and close contact with a confirmed case of COVID-19. CONCLUSIONS: Despite the increase in testing and positive tests over this study period, the incidence of allograft loss or death related to COVID-19 remained extremely low, with allograft loss or death each occurring in < 1% of COVID-19-positive patients and in less than < 0.1% of all transplant patients within the IROC cohort. A higher resolution version of the Graphical abstract is available as Supplementary information.

A Cost-effectiveness Analysis of Adherence Promotion Strategies to Improve Rejection Rates in Adolescent Kidney Transplant Recipients.

RATIONALE & OBJECTIVE: Nonadherence to medical regimens increases the risk of graft loss among adolescent and young adult recipients of kidney transplants. Interventions that improve adherence may decrease rejection rates, but their perceived costs are a barrier to clinical implementation. We developed a model to assess the cost-effectiveness of an adherence promotion strategy, the Medication Adherence Promotion System (MAPS). STUDY DESIGN: Simulation-based. Data sources included published articles indexed in Medline or referenced in bibliographies of relevant English-language articles. Data on costs and outcomes were taken from a single clinical center. SETTING & POPULATION: US adolescent patients after their first kidney transplant. INTERVENTION: Usual posttransplant care versus usual care plus MAPS. OUTCOME: Effectiveness measured in quality-adjusted life years (QALYs) and costs measured in 2020 US dollars. MODEL, PERSPECTIVE, & TIMEFRAME: Markov state transition decision model. We used a health care system perspective with a lifelong time horizon. RESULTS: In the base-case analysis, MAPS was more effective and less costly than usual care. MAPS cost $9,106 per patient less than usual care and resulted in a gain of 0.32 QALYs. In probabilistic sensitivity analyses, MAPS was cost saving 100% of the time. Extending results to a program level with 100 patients, any adherence promotion intervention similar in effectiveness to MAPS would cost less than $50,000/QALY if the start-up costs were <$2.5 million and annual costs <$188,000. Strategies with costs similar to MAPS that reduce the risk of rejection by as little as 3% would also have similar cost-effectiveness. LIMITATIONS: Estimates of components and costs for MAPS were based on a single center. CONCLUSIONS: Adherence promotion strategies with costs similar to MAPS can be cost-effective as long as they reduce rejection rates by at least 3%. This model can be applied to study the cost-effectiveness of adherence promotion strategies with varying costs and outcomes.

A Medication Adherence Promotion System to Reduce Late Kidney Allograft Rejection: A Quality Improvement Study.

RATIONALE & OBJECTIVE: Adolescent and young adult kidney transplant recipients have a high risk of rejection related to suboptimal adherence. Multicomponent interventions improve adherence in controlled trials, but clinical implementation is lacking. We describe an initiative to reduce allograft rejection using evidence-based adherence promotion strategies. STUDY DESIGN: Interrupted time series. SETTING & PARTICIPANTS: Kidney transplant recipients cared for at Cincinnati Children's Hospital ≥ 1 year after transplant and taking ≥1 immunosuppressive medication(s) from 2014 through 2017. QUALITY IMPROVEMENT ACTIVITIES: The following interventions, collectively called MAPS (Medication Adherence Promotion System), were implemented over 14 months: (1) adherence promotion training for clinical staff, 2) electronic health record-supported adherence risk screening, (3) systematic assessment of medication adherence barriers, (4) designation of specific staff to address adherence barriers, (5) shared decision-making with the patients to overcome adherence barriers, (6) follow-up evaluation to assess progress, and (7) optional electronic medication monitoring. OUTCOMES: Primary Outcome: Late acute rejection. Process measures were conducted to assess barriers, identify barriers, and perform interventions. The secondary outcomes/balancing measures were de novo donor-specific antibodies (DSA), biopsy rate, and rejections per biopsy. ANALYTICAL APPROACH: Time series analysis using statistical process control evaluated patient-days between acute rejections as well as monthly rejections per 100 patient-months before and after implementation. To control for known rejection risk factors including changes in treatment and case mix, multivariable analyses were performed. RESULTS: The monthly rejection rate fell from 1.61 rejections per 100 patient-months in the 26 months before implementation to 0.88 rejections per 100 patient-months in the 22 months after implementation. In the multivariable analysis, MAPS was associated with a 50% reduction in rejection incidence (incidence rate ratio, 0.50 [95% CI, 0.27-0.91]; P = 0.02). DSA and time since transplant (per each additional year) were also associated with rejection incidence (incidence rate ratio, 2.27 [P = 0.02] and 0.87 [P = 0.02], respectively). LIMITATIONS: Single-center study, and potential confounding by unmeasured variables. CONCLUSIONS: Clinical implementation of evidence-based adherence-promotion strategies was associated with a 50% reduction in acute rejection incidence over 2 years.

Kidney transplantation in pediatric patients with rheumatologic disorders.

PURPOSE OF REVIEW: Providers caring for children with end-stage kidney disease from rheumatologic conditions face questions such as when to proceed with kidney transplantation, how common is disease recurrence posttransplant, how does recurrent disease impact patient and allograft outcomes, and what approaches are available to prevent and treat recurrent disease. We discuss recent developments and relevant literature that address these questions for the most common rheumatologic disorders that lead to end-stage kidney disease in childhood namely, systemic lupus erythematosus, IgA nephropathy, IgA Vasculitis/Henoch Schoenlein Purpura, and Anti-Neutrophil Cytoplasmic Antibody (ANCA)-associated vasculitis. RECENT FINDINGS: Recent data suggest that children with IgA nephropathy, IgA vasculitis, and ANCA-associated vasculitis have similar patient and allograft survival to other conditions despite the risk of recurrent disease, yet those with lupus have worse posttransplant patient and allograft outcomes. A period of disease quiescence may be prudent prior to transplantation to decrease the risk of recurrence, which is associated with decreased allograft survival. Data on preventive strategies and treatment options are limited. SUMMARY: It is recommended that patients with systemic rheumatologic conditions not be excluded from kidney transplantation but that patients be counseled on the risk of potential recurrent disease with its impact on transplant outcomes.

Primary hyperoxaluria diagnosed after kidney transplant: A review of the literature and case report of aggressive renal replacement therapy and lumasiran to prevent allograft loss.

Primary hyperoxaluria type 1 is a rare inherited disorder caused by abnormal liver glyoxalate metabolism leading to overproduction of oxalate, progressive kidney disease, and systemic oxalosis. While the disorder typically presents with nephrocalcinosis, recurrent nephrolithiasis, and/or early chronic kidney disease, the diagnosis is occasionally missed until it recurs after kidney transplant. Allograft outcomes in these cases are typically very poor, often with early graft loss. Here we present the case of a child diagnosed with primary hyperoxaluria type 1 after kidney transplant who was able to maintain kidney function, thanks to aggressive renal replacement therapy as well as initiation of a new targeted therapy for this disease. This case highlights the importance of having a high index of suspicion for primary hyperoxaluria in patients with chronic kidney disease and nephrocalcinosis/nephrolithiasis or with end stage kidney disease of uncertain etiology, as initiating therapies early on may prevent poor outcomes.

COVID-19 in pediatric kidney transplantation: The Improving Renal Outcomes Collaborative.

There are limited data on the impact of COVID-19 in children with a kidney transplant (KT). We conducted a prospective cohort study through the Improving Renal Outcomes Collaborative (IROC) to collect clinical outcome data about COVID-19 in pediatric KT patients. Twenty-two IROC centers that care for 2732 patients submitted testing and outcomes data for 281 patients tested for SARS-CoV-2 by PCR. Testing indications included symptoms and/or potential exposures to COVID-19 (N = 134, 47.7%) and/or testing per hospital policy (N = 154, 54.8%). Overall, 24 (8.5%) patients tested positive, of which 15 (63%) were symptomatic. Of the COVID-19-positive patients, 16 were managed as outpatients, six received non-ICU inpatient care and two were admitted to the ICU. There were no episodes of respiratory failure, allograft loss, or death associated with COVID-19. To estimate incidence, subanalysis was performed for 13 centers that care for 1686 patients that submitted all negative and positive COVID-19 results. Of the 229 tested patients at these 13 centers, 10 (5 asymptomatic) patients tested positive, yielding an overall incidence of 0.6% and an incidence among tested patients of 4.4%. Pediatric KT patients in the United States had a low estimated incidence of COVID-19 disease and excellent short-term outcomes.

Multicenter data to improve health for pediatric renal transplant recipients in North America: Complementary approaches of NAPRTCS and IROC.

Kidney transplantation increases life expectancy and improves quality of life for children with end-stage kidney disease, yet sequelae of transplantation and treatment make it difficult for transplant recipients to enjoy health and quality of life similar to their healthy peers. The NAPRTCS network was among the first to use multicenter data to inform improvements in care and outcomes for children with a kidney transplant through observational research. Now, with new technologies and unprecedented access to data, it is possible to create learning health systems as envisioned by the US National Academy of Sciences to seamlessly integrate research and continuous improvement of clinical care. In this review, we present two pre-eminent North American networks focused on using multicenter data to drive improved care and outcomes for children with a kidney transplant. Whereas, for the past 30 years NAPRTCS has focused on discovery of best practices through observational research and clinical trials, the Improving Renal Outcomes Collaborative, established in 2016, engages patients, families, clinicians, and researchers in redesigning the healthcare delivery system to enable practice change and continuous improvement of health outcomes. We discuss the history and past contributions of these networks, as well as current activities, barriers, and potential future solutions to more fully realize the vision of a true learning health system for pediatric kidney transplant recipients.

Re-transplantation in pediatric patients with failure of primary transplant due to recurrent focal segmental glomerulosclerosis: A pediatric nephrology research consortium study.

INTRODUCTION: Recurrent focal and segmental glomerulosclerosis (FSGS) in kidney transplant recipients is associated with lower graft survival and increased morbidity. There are limited data to guide the decision to re-transplant patients with transplant failure due to FSGS recurrence. We aimed to evaluate outcomes in patients re-transplanted after having initial graft failure due to recurrent FSGS and to study physician attitudes and practice patterns. METHODS: Retrospective data from 10 centers were collected on 20 patients transplanted between January 1997 and September 2018. A survey was sent to nephrologist members of the Pediatric Nephrology Research Consortium. RESULTS: Mean patient age (years) was 9.8 ± 4.8 at first transplant and 15.9 ± 4.9 at re-transplantation. Pre-transplant plasmapheresis was used in 1 (5.3%) primary transplant vs. 7 (38.9%) re-transplants (p = .03). Nephrotic syndrome recurred in 14 patients (70%) after re-transplantation and was severe in 21.1% vs. 64.7% after first transplant (p = .04). Graft survival was significantly higher in the second transplant (p .009) with 70% having functioning grafts at a median of 25.2 months. Thirty-one physicians from 21 centers completed the survey, 94% indicated they would re-transplant such patients, 44.4% preferred a minimum waiting period before re-transplantation, 36.4% preferred living donors, and 22.2% indicated having protocols for re-transplantation at their centers. CONCLUSIONS: Consideration for re-transplantation is high among pediatric nephrologists. Pre-transplant plasmapheresis was more frequent in re-transplanted patients. Nephrotic syndrome recurrence was less severe, with better graft survival. More data and a larger population are necessary to further evaluate outcome determinants and best practices in this special population.

Predicting acute rejection in children, adolescents, and young adults with a kidney transplant by assessing barriers to taking medication.

BACKGROUND: Nonadherence to immunosuppression is common among pediatric, adolescent, and young adult kidney transplant recipients and a leading cause of graft loss. Assessing barriers to medication adherence in clinical practice may identify patients at risk for rejection and provide therapeutic targets. METHODS: Kidney transplant patients and/or their caregivers were assessed for 14 barriers to medication adherence using the barriers assessment tool. We compared rejection rates between patients with at least one reported adherence barrier to those without reported adherence barriers using a Kaplan-Meier estimator and Cox proportional hazard models to adjust for other mediators of acute rejection at 2 years following barriers assessment. RESULTS: Ninety-eight patients were assessed for barriers to adherence. Over the 2-year observation period, 22 patients developed biopsy-proven acute rejection (BPAR). Kaplan-Meier estimates show that patients with an identified barrier to adherence were more likely to have BPAR (p = 0.02) than patients without an identified barrier in the 24 months following barriers assessment. The median time to rejection for patients who experienced acute rejection was 175.5 days (IQR 63-276 days) from the time of barriers assessment. An identified barrier to adherence remained the only statistically significant predictor of BPAR with Cox modeling (HR 2.6, p = 0.04), after accounting for age, sex, and race. CONCLUSIONS: Pediatric and adolescent kidney transplant recipients with identified adherence barriers are at increased risk for acute rejection. Barriers to adherence provide a potentially modifiable therapeutic target that can be assessed in clinic to guide targeted interventions.

Blood transfusion rates in Baby NINJA (Nephrotoxic Injury Negated by Just-in-Time Action)-a single-center experience.

BACKGROUND: Previous studies in non-critically ill hospitalized pediatric patients have shown that daily serum creatinine monitoring for the development of nephrotoxic medication-associated acute kidney injury decreases both the rate of high nephrotoxic medication exposure and associated acute kidney injury. Attempts to spread this successful screening program have been met with concerns that daily serum creatinine monitoring in critically ill neonates with high-risk nephrotoxic medication exposure would lead to iatrogenic anemia and an increase in blood transfusion requirements. METHODS: We measured blood transfusion rates while implementing a system of daily serum creatinine monitoring in critically ill neonates at risk for high nephrotoxic medication-associated acute kidney injury. RESULTS: There was no correlation between blood transfusion rates and serum creatinine monitoring rates. CONCLUSIONS: We recommend that critically ill neonates identified as having high-risk nephrotoxic medication exposure undergo daily screening for the development of nephrotoxic medication-associated acute kidney injury.

Composite Health Outcomes in Pediatric and Young Adult Kidney Transplant Recipients.

OBJECTIVE: To assess composite health outcomes in pediatric and young adult kidney transplant recipients following kidney transplantation. STUDY DESIGN: We conducted a cross-sectional study of all recipients at our center who had a 1-, 3-, 5-, and/or 10-year transplant anniversary visit between October 2008 and February 2015. The kidney transplant recipients were assessed at each time point according to an outcome measure consisting of 15 pass/fail criteria in 5 domains: allograft health, rejection and immunology, infection, cardiovascular health, and growth. RESULTS: We analyzed 148 patients at 231 transplantation anniversary visit time points; 52 of 82 (63%) patients assessed at 1 year had an ideal outcome, meeting at least 13 of the 15 criteria. This decreased to 37% at year 3, 40% at year 5, and 26% at year 10 (P < .01). The most common failures across all time points occurred in the domains of growth (43%-52% passing) and cardiovascular health (33%-51% passing). Allograft health declined significantly, decreasing from 74% at year 1 to 33% at year 10 (P < .01). The percentage of patients with graft failure increased from 2.4% at 1 year to 39.5% at 10 years (P < .01), and patient deaths increased from 0 to 11% (P < .01) in the same time frame. CONCLUSIONS: Ideal outcomes for pediatric kidney transplant recipients decrease over time with growth, cardiovascular health, and allograft health as the primary failure modes. Understanding the composite health of young recipients will allow primary care providers and nephrologists alike to evaluate the overall health of kidney transplant recipients and focus clinical care on the most common sequelae.

LDL-apheresis-induced remission of focal segmental glomerulosclerosis recurrence in pediatric renal transplant recipients.

BACKGROUND: Focal segmental glomerulosclerosis (FSGS) in pediatric patients is typically difficult to treat and will progress to end-stage renal disease (ESRD) in about 10% of cases. Following kidney transplantation, FSGS can recur in up to 56% of renal allografts-with a near 100% recurrence in subsequent transplants. METHODS: Four different pediatric centers across the USA and the UK employed a protocol using LDL-apheresis (LDL-A) and pulse solumedrol to treat recurrent FSGS after transplantation in seven patients. All the patients included in this series demonstrated immediate, or early, recurrence of FSGS, which clinically presented as nephrotic-range proteinuria within hours to days after implantation of the kidney. RESULTS: All patients experienced reductions in urinary protein to creatinine ratios resulting in partial or complete remission. All patients demonstrated improvements in their estimated GFRs at their most recent follow-up since LDL-A discontinuation. CONCLUSIONS: This case series describes the successful treatment, across four different pediatric centers, of seven pediatric patients with recurrent post-transplant FSGS using the Liposorber® LA-15 in combination with pulse solumedrol.

Quality initiatives in pediatric transplantation.

PURPOSE OF REVIEW: Pediatric transplantation faces unique challenges in implementing dynamic quality improvement measures because of proportionally smaller volumes compared to adults, logistics of being integrated successfully within larger or complex hospital systems, lack of adult-affiliated transplant centers, varying focus in prioritization of relevant outcome metrics, and potential lack of sufficient resources. RECENT FINDINGS: To address these challenges, multiinstitutional collaborations have developed which have proven increasingly effective in driving awareness and quality improvement measures to supplement regulatory efforts in the pediatric population. Relevant work from the Pediatric Heart Transplant Society and Studies in Pediatric Liver Transplantation will be highlighted. The introduction of learning networks such as the Improving Renal Outcomes Collaborative and the Starzl Network for Excellence in Pediatric Transplantation have further focused on continuous learning initiatives in renal and liver transplantation using collaboration and patient informed measures. SUMMARY: Optimal transplant performance improvement is fully integrated into health delivery at all points of the patient pathway. Progress in performance improvement will require ongoing integration of big data solutions, improved patient engagement and technology solutions. VIDEO ABSTRACT:.

Durability of the hepatitis B vaccination in pediatric renal transplant recipients.

Since hepatitis B virus (HBV) vaccine implementation, HBV infection has significantly decreased. However, adult renal transplant recipients show a higher rate of seroreversion compared to the general population, leading to HBV infection risk. Data are limited in pediatric renal transplant recipients. Retrospective data were collected to determine the seroprotection and durability of HBV vaccination in pediatric renal transplant patients from 2004 to 2014. One hundred subjects were categorized based on pre- and post-transplant hepatitis B surface antibody (HBsAb). Pretransplant, 85 recipients (85%) had a positive HBsAb compared to 15 (15%) with negative HBsAb. In univariable analyses, other than age (P < .05) no significant differences existed pretransplant by demographics, pretransplantation dialysis, or number of vaccinations. Of the 85 pretransplantation responders, 53 (62%) remained HBsAb positive post-transplantation, 28 (32%) seroreverted, and 4 developed indeterminate titers. All seroreversions occurred within 5 years post-transplant. Receipt of a living donor organ had higher risk of reversion (P = .005). No significant differences were found in demographics, pretransplantation dialysis, vaccination number, or acute rejection. Despite vaccination, 15% of pediatric renal transplant candidates were seronegative, and an additional 32% lost seroprotection within 5 years post-transplantation leaving nearly half of transplant recipients at risk for HBV infection.

IGG3 anti-HLA donor-specific antibodies and graft function in pediatric kidney transplant recipients.

Anti-HLA DSAs are associated with ABMR and graft loss in KT recipients, yet the influence of DSA IgG subclass on outcomes in pediatric KT recipients is not completely understood. We performed a single-center retrospective chart review of pediatric KT recipients with anti-HLA DSAs, aiming to study the association between specific DSA IgG subclasses and graft outcomes, including ABMR and significant graft dysfunction (graft loss or 50% decrease in eGFR). Thirty-six patients (mean age 15.4y) with DSAs initially detected 1 month-14.3 years post-transplantation were followed for a median of 2.8 years. Rates of IgG1, 2, 3, and 4 subclass detection were 92%, 33%, 58%, and 25%, respectively. Twenty-two patients (61%) had clinical ABMR, whereas 19% had subclinical ABMR, and 13 (36%) experienced significant graft dysfunction. Patients with IgG3+ DSAs had a higher risk of graft dysfunction compared with IgG3- patients (52% vs 13%, P = .03). In a multiple Cox proportional regression analysis, the presence of IgG3+ DSA was independently associated with significant graft dysfunction (HR 10.45, 95% CI 1.97-55.55, P = .006). In conclusion, IgG3 subclass DSAs are associated with graft dysfunction and may be useful for risk stratification and treatment decisions in DSA-positive pediatric KT recipients.

TFE3-positive renal cell carcinoma occurring in three children with dysfunctional kidneys on immunosuppression.

Pediatric RCC is a rare pediatric neoplasm and is distinctly different compared to adult RCC, often demonstrating translocation morphology evidenced by unique histopathological features and TFE3 or TFEB nuclear expression. We report three cases of pediatric TFE3 positive RCC (TFE3-RCC) occurring in the setting of chronic kidney disease and long-term pharmacological immunosuppression, including two cases that developed in the native kidney following kidney transplantation. Together, these cases suggest that the kidney microenvironment in combination with immune dysregulation is likely contributing factors in the pathogenesis of some pediatric RCC, warranting further study. Long-term post-transplant surveillance may warrant screening for RCC.