Steroid-free immunosuppression since 1999: 129 pediatric renal transplants with sustained graft and patient benefits

New insights in immunomodulation for intestinal transplantation

Tolerance is the Holy Grail of solid organ transplantation (SOT) and remains its primary challenge since its inception. In this topic, the seminal contributions of Thomas Starzl at Pittsburgh University outlined foundational principles of graft acceptance and tolerance, with chimerism emerging as a pivotal factor. Immunologically, intestinal transplantation (ITx) poses a unique hurdle due to the inherent characteristics and functions of the small bowel, resulting in increased immunogenicity. This necessitates heavy immunosuppression (IS) while IS drugs side effects cause significant morbidity. In addition, current IS therapies fall short of inducing clinical tolerance and their discontinuation has been proven unattainable in most cases. This underscores the unfulfilled need for immunological modulation to safely reduce IS-related burdens. To address this challenge, the Leuven Immunomodulatory Protocol (LIP), introduced in 2000, incorporates various pro-tolerogenic interventions in both the donor to the recipient, with the aim of facilitating graft acceptance and improving outcome. This review seeks to provide an overview of the current understanding of tolerance in ITx and outline recent advances in this domain.

Early prediction of growth patterns after pediatric kidney transplantation based on height-related single-nucleotide polymorphisms

BACKGROUND

Growth retardation is a common complication of chronic kidney disease in children, which can be partially relieved after renal transplantation. This study aimed to develop and validate a predictive model for growth patterns of children with end-stage renal disease (ESRD) after kidney transplantation using machine learning algorithms based on genomic and clinical variables.

METHODS

A retrospective cohort of 110 children who received kidney transplants between May 2013 and September 2021 at the First Affiliated Hospital of Zhengzhou University were recruited for whole-exome sequencing (WES), and another 39 children who underwent transplant from October 2021 to March 2022 were enrolled for external validation. Based on previous studies, we comprehensively collected 729 height-related single-nucleotide polymorphisms (SNPs) in exon regions. Seven machine learning algorithms and 10-fold cross-validation analysis were employed for model construction.

RESULTS

The 110 children were divided into two groups according to change in height-for-age Z -score. After univariate analysis, age and 19 SNPs were incorporated into the model and validated. The random forest model showed the best prediction efficacy with an accuracy of 0.8125 and an area under curve (AUC) of 0.924, and also performed well in the external validation cohort (accuracy, 0.7949; AUC, 0.796).

CONCLUSIONS

A model with good performance for predicting post-transplant growth patterns in children based on SNPs and clinical variables was constructed and validated using machine learning algorithms. The model is expected to guide clinicians in the management of children after renal transplantation, including the use of growth hormone, glucocorticoid withdrawal, and nutritional supplementation, to alleviate growth retardation in children with ESRD.

Steroid avoidance/withdrawal and maintenance immunosuppression in pediatric kidney transplantation

BACKGROUND

Corticosteroids have been an integral part of maintenance immunosuppression for pediatric kidney transplantation. However, prolonged steroid therapy is associated with significant toxicities resulting in several SW/avoidance strategies in recent years.

METHOD/OBJECTIVE

This comprehensive review aims to discuss steroid-related toxicities and the safety, efficacy, and benefit of steroid avoidance/withdrawal immunosuppression in pediatric kidney transplant recipients.

RESULTS

Initial studies of SW/avoidance conducted in the setting of CSA and AZA showed an increased incidence of AR but no increase in graft loss or mortality with SW/avoidance maintenance immunosuppression. Studies performed under modern immunosuppression (induction therapy, Tac, and MMF) show no significant increase in AR or graft loss with SW/avoidance immunosuppression. Furthermore, SW/avoidance immunosuppression is associated with significant improvement in growth, BMI, BP control, and lipid profile in pediatric kidney transplant recipients. Despite these data, SW/avoidance remains controversial, and only 40% of pediatric kidney transplant recipients in the United States are currently on SW/avoidance maintenance immunosuppression.

CONCLUSION

SW/avoidance maintenance immunosuppression is safe and associated with fewer side effects compared with steroid-inclusive maintenance immunosuppression in pediatric kidney transplant recipients.

Long-term outcome of early steroid withdrawal in pediatric renal transplantation

BACKGROUND

Steroid use in renal transplant is related to multiple adverse effects. Long-term effects of early withdrawal steroids in pediatric renal transplant were assessed.

METHODS

Renal transplant children with low immunological risk treated on basiliximab, tacrolimus, and mycophenolate with steroid withdrawal or steroid control were evaluated between 2003 and 2019. Clinical variables, treatment adherence, acute rejection, graft loss, and death were analyzed through hazard ratios, and Kaplan-Meier and multivariate analyses.

RESULTS

The study included 152 patients, 71.1% steroid withdrawal, mean follow-up 8.5 years, 64.5% structural abnormalities, and 81.6% deceased donor. At 12 years of transplant, event-free survival analysis for graft loss or death showed no significant difference between steroid withdrawal and control steroid treatment (85.9% vs. 80.4%, p = .36) nor in acute rejection at 10 years (18.5% vs. 20.5%, p = .78) or in donor-specific antibody appearance (19.6% vs. 21.4%, p = .98). Delta height Z-score was increased in the steroid withdrawal group (p < .01). The main predictor of graft loss or death was non-adherence to treatment (p = .001; OR: 17.5 [3.3-90.9]).

CONCLUSIONS

Steroid withdrawal therapy was effective and safe for low-risk pediatric renal transplant in long-term evaluation. Non-adherence was the main predictor of graft loss or death.

Induction and maintenance immunosuppression in pediatric kidney transplantation-Advances and controversies

Advances in immunosuppression have improved graft survival in pediatric kidney transplant recipients; however, treatment-related toxicities need to be balanced against the possibility of graft rejection. Several immunosuppressive agents are available for use in transplant recipients; however, the optimal combinations of agents remain unclear, resulting in variations in institutional protocols. Lymphocyte-depleting antibodies, specifically ATG, are the most common induction agent used for pediatric kidney transplantation in the US. Basiliximab may be used for induction in immunologically low-risk children; however, pediatric data are scarce. CNIs and antiproliferative agents (mostly Tac and mycophenolate in recent years) constitute the backbone of maintenance immunosuppression. Steroid-avoidance maintenance regimens remain controversial. Belatacept and mTOR inhibitors are used in children under specific circumstances such as non-adherence or CNI toxicity. This article reviews the indications, mechanism of action, efficacy, dosing, and side effect profiles of various immunosuppressive agents available for pediatric kidney transplantation.

Glucose tolerance in a cohort of Egyptian children after kidney transplantation

BACKGROUND

Post- transplantation diabetes mellitus (PTDM) in children is a serious metabolic complication that can endanger both graft and patient survival. These complications can be partially reduced by early diagnosis & prompt treatment of impaired glucose tolerance. The aim of this study was to assess glucose tolerance & insulin resistance among a cohort of kidney transplanted children.

METHODS

Thirty consecutive pediatric kidney transplant recipients were subjected to basal evaluation of plasma glucose and insulin then underwent oral glucose tolerance test (OGTT).

RESULTS

Abnormal glucose metabolism was detected in 7 (23.3%) patients; 3 (10%) patients with PTDM; 3 (10%) patients with impaired fasting glucose (IFG) and 1 (3.3%) patient with IFG and impaired glucose tolerance (IGT). Four (13.3%) patients had high Homeostatic model assessment of insulin resistance (HOMA-IR). Patients with abnormal glucose metabolism had significantly higher tacrolimus trough levels and higher maintainence steroid doses (p values = 0.003,0.026). Significant positive correlation existed between pre-transplantation glucose level and post-transplantation fasting glucose (p = 0.001, r = 0.69), glucose at 120 min (p = 0.018, r = 0.429) and HOMA-IR (p = 0.008, r = 0.47).

CONCLUSION

Abnormalities in glucose metabolism (IFG, IGT &PTDM) are frequent in Egyptian pediatric kidney transplant recipients. OGTT is the gold standard for assessment of abnormalities in glucose metabolism.

Growth Patterns After Kidney Transplantation in European Children Over the Past 25 Years: An ESPN/ERA-EDTA Registry Study

BACKGROUND

Improved management of growth impairment might have resulted in less growth retardation after pediatric kidney transplantation (KT) over time. We aimed to analyze recent longitudinal growth data after KT in comparison to previous eras, its determinants, and the association with transplant outcome in a large cohort of transplanted children using data from the European Society for Paediatric Nephrology/European Renal Association and European Dialysis and Transplant Association Registry.

METHODS

A total of 3492 patients transplanted before 18 years from 1990 to 2012 were included. Height SD scores (SDS) were calculated using recent national or European growth charts. We used generalized equation models to estimate the prevalence of growth deficit and linear mixed models to calculate adjusted mean height SDS.

RESULTS

Mean adjusted height post-KT was -1.77 SDS. Height SDS was within normal range in 55%, whereas 28% showed moderate, and 17% severe growth deficit. Girls were significantly shorter than boys, but catch-up growth by 5 years post-KT was observed in both boys and girls. Children <6 years were shortest at KT and showed the greatest increase in height, whereas there was no catch-up growth in children transplanted >12.

CONCLUSIONS

Catch-up growth post-KT remains limited, height SDS did not improve over time, resulting in short stature in nearly half of transplanted children in Europe.

Liver Transplant for Posthepatectomy Liver Failure in Hepatoblastoma

OBJECTIVES

Predicting the risk of posthepatectomy liver failure is important when performing extended hepatectomy. However, there is no established method to evaluate liver function and improve preoperative liver function in pediatric patients.

MATERIALS AND METHODS

We show the clinical features of pediatric patients who underwent living donor liver transplant for posthepatectomy liver failure in hepatoblastoma. The subjects were 4 patients with hepatoblastoma who were classified as Pretreatment Extent of Disease III, 2 of whom had distal metastasis (chest wall and lung).

RESULTS

Hepatic right trisegmentectomy was performed in 3 patients and extended left hepatectomy in 1 patient. The median alpha-fetoprotein level at the diagnosis of hepatoblastoma was 986300 ng/mL (range, 22500-2726350 ng/mL), and the median alpha-fetoprotein level before hepatectomy was 8489 ng/mL (range, 23-22500 ng/mL). The remnant liver volume after hepatectomy was 33.3% (range, 20% to 34.9%). Four patients had cholangitis after hepatectomy and progressed to posthepatectomy liver failure. The peak serum total bilirubin after hepatectomy was 11.4 mg/dL (range, 8.7-14.6 mg/dL). Living donor liver transplant was performed for these 4 patients with posthepatectomy liver failure, and they did not have a recurrence.

CONCLUSIONS

When the predictive remnant liver volume by computed tomography-volumetry before extended hepatectomy for patients with hepatoblastoma is less than 40%, the possibility of posthepatectomy liver failure should be recognized.

Incidence and Risk Factors of Obesity in Childhood Solid-Organ Transplant Recipients

BACKGROUND

Obesity is a significant public health concern; however, the incidence post solid-organ transplantation is not well reported.

METHODS

This study determined the incidence and risk factors of obesity among pediatric solid-organ transplant recipients (heart, lung, liver, kidney, multiorgan) at The Hospital for Sick Children (2002-2011), excluding prevalent obesity. Follow-up occurred from transplantation until development of obesity, last follow-up, or end of study. Incidence of obesity was determined overall, by baseline body mass index, and organ group. Risk factors were assessed using Cox proportional-hazards regression.

RESULTS

Among 410 (55% male) children, median transplant age was 8.9 (interquartile range [IQR]: 1.0-14.5) years. Median follow-up time was 3.6 (IQR: 1.5-6.4) years. Incidence of obesity was 65.2 (95% confidence interval [CI]: 52.7-80.4) per 1000 person-years. Overweight recipients had a higher incidence, 190.4 (95% CI: 114.8-315.8) per 1000 person-years, than nonoverweight recipients, 56.1 (95% CI: 44.3-71.1). Cumulative incidence of obesity 5-years posttransplant was 24.1%. Kidney relative to heart recipients had the highest risk (3.13 adjusted hazard ratio [aHR]; 95% CI: 1.53-6.40) for obesity. Lung and liver recipients had similar rates to heart recipients. Those with higher baseline body mass index (z-score; 1.72 aHR; 95% CI: 1.39-2.14), overweight status (2.63 HR; 95% CI: 1.71-4.04), and younger transplant age (y; 1.18 aHR; 95% CI: 1.12-1.25) were at highest risk of obesity. Higher cumulative steroid dosage (per 10 mg/kg) was associated with increased risk of obesity after adjustment.

CONCLUSIONS

Among all transplanted children at The Hospital for Sick Children, 25% developed obesity within 5-years posttransplant. Kidney recipients, younger children, those overweight at transplant, and those with higher cumulative steroid use (per 10 mg/kg) were at greatest risk. Early screening and intervention for obesity are important preventative strategies.

Linear Growth in Pediatric Kidney Transplant Population

Introduction: Growth retardation is one of the main complications of chronic kidney disease (CKD) in children and induces a negative impact on quality of life. Materials and Methods: Retrospective analysis of all consecutive patients younger than 18 years old who received a first KT in our center between 2008 and 2018. Results: 95 first KT recipients, median age at KT of 7.83 years. At the time of KT, 65.52% of males and 54.05% females showed normal height. After transplantation, linear growth improved from -1.53 at transplant to -1.37 SDS height at the last visit. We detected a different linear growth pattern according to patient age at KT. Children younger than 3 years old exhibited the most significant growth retardation at baseline and the greatest linear growth over time (-2.29 vs. -1.82 SDS height), whereas catch-up was not observed in older patients. Multivariate analysis showed that use of corticosteroids was negatively related to SDS height at 1 year after transplantation and final SDS height only was positively associated with SDS height at KT. 44.2 and 22.1% patients received rhGH treatment before and after KT. 71.88% patients reached adulthood with normal final height. Conclusions: In our study, pediatric KT recipients exhibited a normal height in more than half of cases at KT and in more than two thirds at the final adult height. Only children younger than 6 years old presented a relevant growth catch-up after KT. Treatment with rhGH was used before and after KT with significant improvement in height.

Characterizing pre-transplant and post-transplant kidney rejection risk by B cell immune repertoire sequencing

Studying immune repertoire in the context of organ transplant provides important information on how adaptive immunity may contribute and modulate graft rejection. Here we characterize the peripheral blood immune repertoire of individuals before and after kidney transplant using B cell receptor sequencing in a longitudinal clinical study. Individuals who develop rejection after transplantation have a more diverse immune repertoire before transplant, suggesting a predisposition for post-transplant rejection risk. Additionally, over 2 years of follow-up, patients who develop rejection demonstrate a specific set of expanded clones that persist after the rejection. While there is an overall reduction of peripheral B cell diversity, likely due to increased general immunosuppression exposure in this cohort, the detection of specific IGHV gene usage across all rejecting patients supports that a common pool of immunogenic antigens may drive post-transplant rejection. Our findings may have clinical implications for the prediction and clinical management of kidney transplant rejection.

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.

Diabetes mellitus in pediatric solid organ recipients without and with cystic fibrosis: An analysis from the German-Austrian diabetes database (Diabetes Patienten Verlaufsdokumentation)

INTRODUCTION

Posttransplantation diabetes mellitus (PTDM) increases the risk of cardiovascular disease, graft loss, and decreased survival. Follow-up treatment after solid organ transplantation (SOT) needs to focus on, inter alia, maintaining balanced glucose metabolism. This study aimed to ascertain the prevalence of PTDM and describe patient characteristics in the large DPV (Diabetes Patienten Verlaufsdokumentation) pediatric diabetes database.

METHODS

DPV data of 71 902 patients from the January 01, 1995 to January 04, 2015 period were analyzed for patients with and without cystic fibrosis (CF) after SOT (kidney, liver, heart, and lung). Multivariable analysis served to assess differences between SOT patient groups at risk for developing diabetes.

RESULTS

Out of 109 SOT patients, 51 had CF; 72.5% received steroids and 62% were additionally given tacrolimus. PTDM developed in 45% of CF patients and 12% of non-CF patients. SOT patients were older at diabetes onset (mean age, 12.50 ± 3.98 years), shorter (height z-score, -1.67 ± 1.25), and lighter (weight z-score, -1.59 ± 1.57) than non-SOT diabetes patients (P < 0.01). With transplantation, glycated hemoglobin (HbA1c) was significantly lower and treatment for hypertension and dyslipidemia was increased. Among SOT patients, weight and body mass index (BMI) z-scores were significantly lower in patients with CF-related diabetes (P < 0.05).

CONCLUSIONS

SOT was present in 6.6% of children with diabetes, and this might aggravate the risk of cardiovascular disease in populations with already increased rates of hypertension and dyslipidemia. Dystrophy and short stature were also present, particularly in transplant recipients with CF and diabetes. Comorbidities and long-term consequences call for multidisciplinary collaboration.

Safety and utility of surveillance biopsies in pediatric kidney transplant patients

There is currently no way to diagnose a rejection before a change in serum creatinine. This had led some to start doing SB, but little data exist on the utility and safety of SB in pediatric patients. There is also little known on practice patterns of pediatric nephrologists. A retrospective review of pediatric kidney transplant SB between January 2013 and January 2017 at a single center was performed. A survey went to the PedNeph email list. There were 47 SB; 15 at 6 months, 12 at 1 year, 13 at 2 years, and 7 at 3 years. There were 3 minor (1 gross hematuria and 2 hematomas) and no major complications. On 6-month SB, 1 had SC 1A ACR (6.7%) with no BR ACR. On the 12-month SB, there were 5 with SCBR ACR (41.7%) and 1 with SC AMR (8.3%). On the 2-year SB, there were 4 that had SCBR ACR (30.8%), and 1 with SC AMR (7.7%). On the 3-year SB, 1 had chronic transplant glomerulitis (14.3%). The survey showed that 34.3% of pediatric nephrologists perform SB. SB can be performed safely. By early identification of histological lesions, SB gives us an opportunity for individualized immunosuppressive regimens that may prevent chronic allograft dysfunction and improve long-term graft outcome.

Graft survival of pediatric kidney transplant recipients selected for de novo steroid avoidance-a propensity score-matched study

Background

Steroid-avoidance protocols have gained popularity in pediatric kidney transplant recipients at low immunologic risk. The long-term safety of steroid avoidance in children with immunologic risk factors remains unknown.

Methods

Pediatric kidney transplant recipients from 2004 to 2014 in the Organ Procurement and Transplantation Network database who received tacrolimus and mycophenolate immunosuppression were investigated. Propensity score matching was used to compare graft survival in 1624 children who received steroid avoidance with 1624 children who received steroid-based immunosuppression. The effect of steroid avoidance on graft failure among immunologic risk strata was estimated using Cox proportional hazards regression in this propensity score-matched cohort.

Results

It was observed that 5-year graft survival was mildly improved in children receiving steroid avoidance (84.8% versus 81.2%, P = 0.03). This improvement in graft survival occurred in the first 2 years following transplant, when the hazard ratio (HR) for allograft failure in children receiving steroid avoidance was 0.62 [95% confidence interval (CI) 0.45-0.86]. In contrast, steroid avoidance was not associated with improved allograft survival during Years 2-10 following transplant (HR = 0.93; 95% CI 0.75-1.15). During this time period, HRs (95% CIs) for allograft failure within immunologic risk strata were not significantly different from the null value of 1: repeat kidney transplants, 1.84 (0.84-4.05); African-Americans, 1.02 (0.67-1.56); sensitized recipients, 1.24 (0.63-2.43); recipients of deceased donor kidneys, 1.02 (0.79-1.32); recipients of completely human leukocyte antigen-mismatched kidneys, 0.80 (0.47-1.37); and recipients with pretransplant glomerular disease, 0.94 (0.71-1.23).

Conclusions

In pediatric kidney transplant recipients receiving tacrolimus- and mycophenolate-based immunosuppression, steroid avoidance can be safely practiced in children with immunologic risk factors.

Special Considerations in Pediatric Kidney Transplantation

Universally accepted as the treatment of choice for children needing renal replacement therapy, kidney transplantation affords children the opportunity for an improved quality of life over dialysis therapy. Immunologic and surgical advances over the last 15 years have improved the pediatric patient and kidney graft survival. Unique to pediatrics, congenital genitourinary anomalies are the most common primary diseases leading to kidney failure, many with urological issues. Early urological evaluation for post-transplant bladder dysfunction and emphasis on immunization adherence are the mainstays of pediatric pretransplant and post-transplant evaluations. A child's height can be challenging, sometimes requiring an intra-abdominally placed graft, particularly if the patient is <20 kg. Maintenance immunosuppression regimens are similar to adult kidney graft recipients, although distinctive pharmacokinetics may change dosing intervals in children from twice a day to thrice a day. Viral infections and secondary malignancies are problematic for children relative to adults. Current trends to reduce/remove corticosteroid therapy from post-transplant protocols have produced improved linear growth with less steroid toxicity; although these studies are still ongoing, graft function and survival are considered acceptable. Finally, all children with a kidney transplant need a smooth transition to adult clinics. Future research in pertinent psychosocial aspects and continued technological advances will only serve to optimize the transition process. Although some aspects of kidney transplantation are similar in children and adults, for instance immunosuppression and immunosuppressive regimens, and rejection mechanisms and their diagnosis using the Banff criteria, there are important differences this review will focus on and which continue to drive innovation.

Intragraft Antiviral-Specific Gene Expression as a Distinctive Transcriptional Signature for Studies in Polyomavirus-Associated Nephropathy

BACKGROUND

Polyomavirus nephropathy (PVAN) is a common cause of kidney allograft dysfunction and loss. To identify PVAN-specific gene expression and underlying molecular mechanisms, we analyzed kidney biopsies with and without PVAN.

METHODS

The study included 168 posttransplant renal allograft biopsies (T cell-mediated rejection [TCMR] = 26, PVAN = 10, normal functioning graft = 73, and interstitial fibrosis/tubular atrophy = 59) from 168 unique kidney allograft recipients. We performed gene expression assays and bioinformatics analysis to identify a set of PVAN-specific genes. Validity and relevance of a subset of these genes are validated by quantitative polymerase chain reaction and immunohistochemistry.

RESULTS

Unsupervised hierarchical clustering analysis of all the biopsies revealed high similarity between PVAN and TCMR gene expression. Increased statistical stringency identified 158 and 252 unique PVAN and TCMR injury-specific gene transcripts respectively. Although TCMR-specific genes were overwhelmingly involved in immune response costimulation and TCR signaling, PVAN-specific genes were mainly related to DNA replication process, RNA polymerase assembly, and pathogen recognition receptors. A principal component analysis (PCA) using these genes further confirmed the most optimal separation between the 3 different clinical phenotypes. Validation of 4 PVAN-specific genes (RPS15, complement factor D, lactotransferrin, and nitric oxide synthase interacting protein) by quantitative polymerase chain reaction and confirmation by immunohistochemistry of 2 PVAN-specific proteins with antiviral function (lactotransferrin and IFN-inducible transmembrane 1) was done.

CONCLUSIONS

In conclusion, even though PVAN and TCMR kidney allografts share great similarities on gene perturbation, PVAN-specific genes were identified with well-known antiviral properties that provide tools for discerning PVAN and AR as well as attractive targets for rational drug design.

Corticosteroid Use and Growth After Pediatric Solid Organ Transplantation: A Systematic Review and Meta-Analysis

BACKGROUND

A number of corticosteroid minimization and avoidance protocols for post-solid organ transplant have been developed. The study objective was to examine the effect of corticosteroid withdrawal/avoidance on growth and safety parameters in pediatric solid organ transplant recipients.

METHODS

A systematic review using Medline and Embase was performed. All randomized controlled trials (RCT) and observational studies comparing corticosteroid withdrawal/avoidance to controls receiving corticosteroids in pediatric transplant recipients which reported growth as change in height or final height were included. Two reviewers independently abstracted study data and assessed quality.

RESULTS

The search yielded 930 records, 14 separate studies involving 1146 patients. Renal RCTs (n = 5) showed that corticosteroid withdrawal/avoidance was associated with a significant increase in growth (mean difference in height standard deviation score [SDS], 0.18; 95% confidence interval [95% CI], 0.07-0.29; P = 0.001) compared with those remaining on steroids. In liver RCTs (n = 2), mean difference in height SDS was -0.20 (95% CI, -1.08 to 0.68; P = 0.66). Results for renal observational studies (n = 5) was 0.34 (95% CI, 0.03-0.65; P = 0.03). The most pronounced effect was seen in prepubertal children with SDS of 0.28 (95% CI, 0.14-0.41; P < 0.0001). In pubertal participants this was not observed (SDS, 0.06; 95% CI, -0.04 to 0.15; P = 0.24). Corticosteroid withdrawal/avoidance was not associated with acute rejection (odds ratio [OR], 0.87; P = 0.63), graft failure (OR, 0.45; P = 0.08), or death (OR, 0.34; P = 0.16) in renal trials.

CONCLUSIONS

Corticosteroid withdrawal/avoidance in pediatric renal transplantation is associated with a significant improvement in height. Prepubertal patients appeared to have the greatest benefit. Importantly, the improvement in growth was not accompanied by increased rejection or worsening patient/allograft survival in the short term.

Hypomagnesemia and increased risk of new-onset diabetes mellitus after transplantation in pediatric renal transplant recipients

BACKGROUND

New-onset diabetes after transplantation (NODAT) is a significant co-morbidity following kidney transplantation. Lower post-transplant serum magnesium levels have been found to be an independent risk factor for NODAT in adult kidney transplant recipients.

METHODS

We undertook a retrospective analysis of risk factors for NODAT in pediatric renal transplant recipients at our institution with the aim of determining if hypomagnesemia confers a significant risk of developing NODAT in this patient population.

RESULTS

A total of 173 children with a median age at transplantation of 7.0 (range 1.3-17.5) years were included. Hypomagnesemia was found to be a significant independent risk factor for NODAT (p = 0.01). High trough tacrolimus levels were also independently associated with NODAT (p < 0.001). There was no significant association between NODAT and body mass index at the time of transplantation, monthly cumulative steroid dose or post-transplant cytomegalovirus viremia (p = 0.9, 0.6 and 0.7, respectively).

CONCLUSIONS

This study identifies hypomagnesemia as a significant independent risk factor for the development of NODAT in pediatric renal transplant recipients. Given the clear association between hypomagnesemia and NODAT in both adults and children following renal transplantation, further studies are merited to clarify the etiology of this association and to examine the effect of magnesium supplementation on NODAT.

Renal transplantation in infants

Renal transplantation (RTx) has become an accepted mode of therapy in infants with severe renal failure. The major indications are structural abnormalities of the urinary tract, congenital nephrotic syndrome, polycystic diseases, and neonatal kidney injury. Assessment of these infants needs expertise and time as well as active treatment before RTx to ensure optimal growth and development, and to avoid complications that could lead to permanent neurological defects. RTx can be performed already in infants weighing around 5 kg, but most operations occur in infants with a weight of 10 kg or more. Perioperative management focuses on adequate perfusion of the allograft and avoidance of thrombotic and other surgical complications. Important long-term issues include rejections, infections, graft function, growth, bone health, metabolic problems, neurocognitive development, adherence to medication, pubertal maturation, and quality of life. The overall outcome of infant RTx has dramatically improved, with long-term patient and graft survivals of over 90 and 80 %, respectively.

Outcomes of two-drug maintenance immunosuppression for pediatric renal transplantation: 10-yr follow-up in a single center

Minimizing IS to reduce side effects without compromising long-term renal transplant survival is the goal of all IS protocols. We conducted a retrospective study of pediatric renal transplants performed August 1988 to July 2008 and treated with two-drug maintenance therapy by one of three protocols: prednisone/cyclosporine without induction (SB) or with daclizumab induction (SBI), or tacrolimus/mycophenolate with daclizumab induction (SF). Kaplan-Meier survival curves were used to determine graft and patient survival at one, three, five, and 10 yr. Associations between graft survival and patient/transplant characteristics were determined using log-rank test and CPH model adjusting for treatment group. About 208 patients were included in the analysis (96 SB, 97 SBI, 15 SF; 148 DD, 60 LD, 37 pre-emptive). Overall graft and patient survival at one, three, five, and 10 yr were similar to the previously published results of pediatric renal transplants in similar years treated predominantly with three-drug maintenance therapy (https://web.emmes.com/study/ped/annlrept/2010). Only biopsy-proven TG was significantly associated with worse graft survival (HR 11.5, 95% CI: 3.4, 38.7). Malignancy rate was low (2.4%) with little PTLD (0.5%). Few opportunistic or other infections occurred (<5% patients). Minimizing IS to a two-drug maintenance regimen had no adverse effect on long-term transplant outcome and had low malignancy and infection rates.

Improved cardiovascular risk factors in pediatric renal transplant recipients on steroid avoidance immunosuppression: A study of the Midwest Pediatric Nephrology Consortium

Several centers have examined the implementation of immunosuppression protocols that minimize steroid exposure. This study retrospectively examined cardiovascular risk factors in 70 pediatric renal transplant recipients on steroid avoidance-based immunosuppression over three yr compared to matched pediatric patients maintained on chronic corticosteroids. Although higher rates of acute rejection were noted in the steroid-avoidant group (22% vs. 16%, p = 0.034), graft function was similar (67 + 10 mL/min/1.73 m(2) vs. 72 + 12 mL/min/1.73 m(2)) (p = 0.053). The steroid-avoidant group demonstrated improved growth (height z-score -0.41 + 5.9 vs. -1.1 + 0.041) with a decrease in the prevalence of obesity (24% vs. 34%, p = 0.021). Indexed systolic blood pressures were lower beginning at six months post-transplant in the steroid-avoidant group (1.21 + 0.15 vs. 1.51 + 0.22, p = 0.020). Indexed diastolic blood pressures were lower beginning at 12 months post-transplant (0.91 + 0.11 vs. 1.12 + 0.18, p = 0.037). Differences in total serum cholesterol values and serum glucose values were not statistically significant. Beginning at 12 months, a statistically significant decrease in left ventricular mass index (39.2 + 11.3 vs. 49.4 + 14.5, p = 0.014) was noted in patients on steroid-avoidant immunosuppression, which corresponded to a significant decrease in the prevalence of left ventricular hypertrophy in these patients by two yr post-transplant (35% vs. 48%, p = 0.012). Systolic blood pressure and BMI were independent predictors of left ventricular hypertrophy.

Long-term effects of paediatric kidney transplantation

Renal transplantation in paediatric patients usually provides excellent short-term and medium-term results. Early diagnosis of chronic kidney disease and active therapy of end-stage renal disease before and after transplantation enables the majority of children to grow and develop normally. The adverse effects of immunosuppressive medication and reduced graft function might, however, hamper long-term outcomes in these patients and can lead to metabolic complications, cardiovascular disease, reduced bone health, and malignancies. The neurocognitive development and quality of life of paediatric transplant recipients largely depend on the primary diagnosis and on graft function. Poor adherence to immunosuppression is an important risk factor for graft loss in adolescents, and controlled transition to adult care is of utmost importance to ensure a continued normal life. In this Review, we discuss the outcomes and long-term effects of renal transplantation in paediatric recipients, including consequences on growth, development, bone, metabolic, and cardiovascular disorders. We discuss the key problems in the care of paediatric renal transplant recipients and the remaining challenges that should be the focus of future research.

Corticosteroid-free Kidney Transplantation Improves Growth: 2-Year Follow-up of the TWIST Randomized Controlled Trial

BACKGROUND

Corticosteroid withdrawal (CW) after pediatric kidney transplantation potentially improves growth while avoiding metabolic and other adverse events. We have recently reported the results of a 196 subject randomized controlled trial comparing early CW (tacrolimus, mycophenolate mofetil (MMF), daclizumab, and corticosteroids until day 4) with tacrolimus, MMF, and corticosteroid continuation (CC). At 6 months, CW subjects showed better growth with no adverse impact on acute rejection or graft survival (Am J Transplant 2010; 10: 828-836). This 2-year investigator-driven follow-up study aimed to determine whether improved growth persisted in the longer term.

METHODS

Data regarding growth, graft outcomes and adverse events were collected at 1 year (113 patients) and 2 years (106 patients) after transplantation. The primary endpoint, longitudinal growth calculated as delta height standard deviation score, was analyzed using a mixed model repeated measures model.

RESULTS

Corticosteroid withdrawal subjects grew better at 1 year (difference in adjusted mean change, 0.25; 95% confidence interval, 0.10, 0.40; P = 0.001). At 2 years, growth remained numerically better in CW subjects (0.20 (-0.01, 0.41); P = 0.06), and significantly better in prepubertal subjects (0.50 (0.16, 0.84); P = 0.004). Bacterial and viral infection was significantly more common in CW subjects at 1 year only. Corticosteroid withdrawal and CC subjects received similar exposure to both tacrolimus and MMF at 1 and 2 years. No significant difference in patient or graft survival, rejection, estimated glomerular filtration rate, or other adverse events was detected.

CONCLUSION

Early CW effectively and safely improves growth up to 2 years after transplantation, particularly in prepubertal children.

New-onset diabetes after kidney transplant in children

The development of new-onset diabetes after kidney transplantation (NODAT) is associated with reduced graft function, increased cardiovascular morbidity and lower patient survival among adult recipients. In the pediatric population, however, the few studies examining NODAT have yielded inconsistent results. Therefore, the true incidence of NODAT in the pediatric population has been difficult to establish. The identification of children and adolescents at risk for NODAT requires appropriate screening questions and tests pre- and post-kidney transplant. Several risk factors have been implicated in the pathogenesis of NODAT and post-transplant glucose intolerance, including African American race, obesity, family history of diabetes and the type of immunosuppressant regimen. Moreover, uremia per se results in a state of insulin resistance that increases the risk of developing diabetes post-transplant. When an individual becomes glucose intolerant, early lifestyle modification and antihyperglycemic measures with tailoring of the immunosuppressant regimen should be implemented to prevent the development of NODAT. For the child or adolescent with NODAT, antihyperglycemic therapy should be prescribed in order to achieve optimal glycemic control, ultimately reducing complications and improving overall allograft and patient survival. In this article, we review the risk factors, screening methods, diagnosis, management and outcome of children and adolescents with NODAT and post-kidney transplant glucose intolerance.

Growth following solid organ transplantation in childhood

One of the ultimate goals of successful transplantation in pediatric solid organ transplant recipients is the attainment of optimal final adult height. This manuscript will discuss the attainment of height following solid organ transplantation in pediatric recipients of kidney, liver, heart, lung, and small bowel transplantation. Age is a primary factor with younger recipients exhibiting the greatest immediate catch up growth. Graft function is a significant contributory factor with a reduction in glomerular filtration rate correlating with poor growth in kidney recipients and the need for re-transplantation with impaired growth in liver recipients. The known adverse impact of steroids on growth has led to modification of steroid dosage and even to steroid withdrawal and steroid avoidance. In kidney and liver recipients, this has been associated with the development on occasion of acute rejection episodes. In infant heart transplantation, avoidance of maintenance corticosteroid immunosuppression is associated with normal growth velocity in the majority of patients. With marked improvement in patient and graft survival rates in pediatric organ graft recipients, it is timely that the quality of life issues, such as normal adult height, receive paramount attention. In general, normal growth post-transplantation should be an achievable goal that results in normal adult height for many solid organ transplantation recipients.

Long-term experience of steroid-free pediatric renal transplantation: effects on graft function, body mass index, and longitudinal growth

Increased focus on the potential negative side effects of steroid usage in pediatric transplantation has led to steroid minimization or steroid-free transplantation. In this study, we report results after complete steroid avoidance in renal transplantation in the period 1994-2009. We evaluate the effects of complete steroid avoidance on allograft function, BMI, and linear growth. The majority of transplanted children were induced with antithymocyte globulin and immunosuppressed with a calcineurin inhibitor and mycophenolate mofetil. Steroids were given only when rejection occurred or due to comorbidities. Anthropometric data were collected from 65 transplantations in 60 children. Patient survival was 93%; graft survival was 81% after five yr (N = 42) and 63% after 10 yr (N = 16). Acute rejection within the first year of transplantation was 9%. The distribution of the children's BMI before transplantation was normal; the mean BMI-SDS was 0.21 before transplantation, and this value remained stable during the next five yr. Post-transplantation the children demonstrated significant improved growth as the mean height-SDS increased significantly from -1.7 to -1.1. Catch-up growth was most pronounced in the youngest (< six yr). Steroid-free immunosuppression in pediatric renal transplantation is safe and protects against steroid-induced obesity and short stature.

Surgical complications and graft survival in pediatric kidney transplant recipients treated with a steroid-free protocol: experiences from a Danish university hospital

BACKGROUND

The outcome of pediatric kidney transplantation depends on several factors, among these are the complications, which occur in relation to the surgical procedure. In this study, we present our experience with pediatric kidney transplantation in a steroid-free immunosuppression regimen, from a surgical point of view.

METHODS

Patient charts of pediatric kidney transplantations in the period 1998-2011 were reviewed. Surgical complications, acute rejection, and patient and graft survivals were recorded.

RESULTS

Sixty-one renal transplantations were performed in 58 patients. Thirty patients (49.1%) experienced a surgical complication, of which 11 (18%) required an explorative laparotomy. Overall the five-year Kaplan-Meier patient survival rate was 96.2% and the graft survival rate was 88.6%. Nine patients (14.7%) had an acute rejection episode within the first year after transplantation. No correlation was observed between surgical complications and acute rejection episodes or graft loss.

CONCLUSIONS

This study indicated a high incidence of surgical complications among pediatric kidney transplantations when using a steroid-free immunosuppression regimen. Despite this, we observed high overall patient and graft survival, supporting the trend toward steroids avoidance in pediatric kidney transplantation.

Steroid withdrawal in renal transplantation

Over the last decade, steroid minimization became one of the major goals in pediatric renal transplantation. Different protocols have been used by individual centers and multicenter study groups, including early and late steroid withdrawal or even complete avoidance. The timing of steroid withdrawal determines if antibodies are used, as avoidance and early withdrawal require antibody induction, while late withdrawal typically does not. A monoclonal antibody was used in most protocols during an early steroid withdrawal together with tacrolimus and mycophenolate mofetil in low immunological risk patients. Polyclonal induction was reported as effective in high-risk patients. Cyclosporine A and mycophenolate mofetil were used in late steroid withdrawal with no induction. All described protocols were effective in terms of preventing acute rejection and preserving renal graft function. There was no superiority of any specific protocol in terms of clinical benefits of steroid withdrawal. Pre-puberty determined growth benefit while other clinical advantages, including better control of glycemia, lipids, and blood pressure, were age independent. It is not clear whether the steroid withdrawal increases the risk of recurrence of primary glomerular diseases post-transplant, however it cannot be excluded. There is no evidence to date for a higher risk of anti-HLA production in steroid-free children after renal transplantation. Key summary points--Current strategies to minimize the steroid-related adverse effects in pediatric renal graft recipients include steroid withdrawal, early or late after transplantation, or complete steroid avoidance--Early steroid withdrawal or avoidance is generally used following the induction therapy with mono- or polyclonal antibodies, while in late steroid withdrawal induction therapy was generally not used- Elimination of steroids (early or late) does not increase the risk of acute rejection and does not deteriorate long-term renal graft function- Early steroid withdrawal is possible in patients at high immunological risk using a combination of polyclonal antibody induction, tacrolimus, and mycophenolate mofetil- All protocols of steroid minimization showed relevant clinical benefits, however the growth-related benefit was limited to pre-pubertal patients in all but one of the studies- Adverse events of steroid withdrawal occurred in a higher incidence of post-transplant bone marrow suppression Key research points - There is no clear evidence of the impact of steroid withdrawal on the risk of recurrence of primary glomerulonephritis after renal transplantation in children, therefore further evaluation of this important issue should be performed in prospective trials- There is limited pediatric data on the risk of anti-HLA/donor-specific antibody production in steroid-free patients after renal transplantation. It is not clear whether the selection of the type of induction antibody (lymphocyte depleting versus short, two-dose administration of anti-IL2R inhibitor) is important in this term. The production of anti-HLA antibodies should then be monitored on a regular basis and analyzed in prospective trials.

Steroid withdrawal in pediatric kidney transplant allows better growth, lipids and body composition: a randomized controlled trial

BACKGROUND

Glucocorticoid immunosuppressant therapy in pediatric kidney transplant (Tx) recipients does not allow the improvement of growth after Tx.

OBJECTIVE

To determine the effect of early steroid withdrawal (SW) on longitudinal growth, insulin sensitivity (IS), and body composition (BC).

METHODS

This was a prospective, randomized, multicenter study in Tx. Insulin-like growth factor (IGF)-I, IGF-binding protein 3 (IGFBP3), IS, and BC (DEXA/pQCT) were determined at baseline and up to 12 months after Tx.

RESULTS

A total of 30 patients were examined; 14 patients were assigned to the SW group (7 male, 7 female; 12 in Tanner stage I) and 16 patients were assigned to the steroid control (SC) group (10 male, 6 female;12 in Tanner stage I). Their chronological age was 7.8 ± 4.3 years, height was -2.3 ± 0.99 SD scores (SDS), and body mass index -0.3 ± 1.2 SDS. After 1 year, the SW group showed an increase in height SDS (+1.2 ± 0.22 vs. +0.60 ± 0.13 SDS in the SC group, p < 0.02), lower IGFBP3 (p < 0.05), cholesterol (p < 0.05), and higher high-density lipoprotein cholesterol (p < 0.05). SW patients had lower trunk fat with no differences in IS. Only in prepubertal patients, the SW group had lower glycemia (p < 0.05), very low-density lipoprotein cholesterol (p < 0.01), triglycerides (p < 0.05), triglycerides/glycemia index (TyG; p < 0.02), and better lean mass. Both groups showed an improvement in lean mass after kidney Tx.

CONCLUSIONS

SW improved longitudinal growth, lipid profile, and trunk and lean fat in Tx patients. In prepubertal recipients, the decrease in TyG suggests better IS.

Final adult height in kidney recipients who underwent highly successful transplantation as children: a single-center experience

BACKGROUND

Achieving a normal final adult height (FH) remains a challenge in the field of pediatric kidney transplantation (KTx). To examine the optimal approach to assuring normal FH following KTx, we retrospectively examined the post-transplant growth and FH of pediatric KTx recipients.

METHODS

Since the relevant factors affecting the FH of children following KTx are multifactorial and notably complex, KTx recipients with persistent good graft function and successful steroid minimization until FH attainment were selected for this study.

RESULTS

Thirteen patients were enrolled in this study. The mean estimated glomerular filtration rate was 72.1 ± 15.3 ml/min/1.73 m(2), and the mean corticosteroid dose was 0.05 ± 0.05 mg/kg on alternate days at the time of FH attainment. Despite highly successful KTx, four (30.8 %) patients (one who underwent KTx before puberty and three during puberty) showed a decrease in the height standard deviation score (hSDS) from the time of KTx until FH attainment. Moreover, of these, two male patients had an FH with an SD <-2.

CONCLUSION

FH remained suboptimal despite highly successful KTx. Not only highly successful KTx but also further treatment such as steroid avoidance, early steroid withdrawal or using rhGH might be necessary to assure a normal FH in some pubertal patients.

A comparison of traditional versus contemporary immunosuppressive regimens in pediatric heart recipients

OBJECTIVES

To assess the differences in rejection and infection complications between the most common contemporary immunosuppression regimen in pediatric heart transplantation (cytolytic induction, tacrolimus based) and classic triple-therapy (cyclosporine based without induction).

STUDY DESIGN

We performed a retrospective, historical-control, observational study comparing outcomes in patients who underwent traditional immunosuppression (control group, n = 64) with those for whom the contemporary protocol was used (n = 39). Episodes of rejection, viremia (cytomegalovirus or Epstein-Barr virus), serious bacterial or fungal infections, anemia or neutropenia requiring treatment in the first year after heart transplantation, and 1-year survival were compared between traditional and contemporary immunosuppression groups.

RESULTS

The 2 groups were similar with respect to baseline demographics. There were no differences in risk of cytomegalovirus, Epstein-Barr virus, or bacterial or fungal infections in the first year post-transplantation. Patients in the contemporary group were more likely to need therapy for anemia (51% vs 14%, P < .001) or neutropenia (10% vs 0%, P = .019). However, more contemporary protocol patients were rejection-free in the first year post-transplantation (63% vs 41%, P = .03). Overall graft survival was similar between groups (P = .15).

CONCLUSIONS

A contemporary immunosuppression regimen using tacrolimus, mycophenolate mofetil, and induction was associated with less rejection in the first year, with no difference in the risk of infection but greater risk of anemia and neutropenia requiring treatment. Long-term follow-up on these patients will evaluate the impact of the immunosuppression regimen on survival.

Reliable individualized monitoring improves cholesterol control in kidney transplant recipients

OBJECTIVE

To develop and evaluate a system for reliable and efficient individualized risk-based monitoring of cholesterol and 11 other tests after kidney transplantation in children.

METHODS

We identified system components that drive reliable individualized monitoring and used quality improvement methods to develop and implement interventions, including (1) monitoring schedules individualized by dyslipidemia risk assigned to each patient, (2) automated previsit decision support from our electronic medical record, (3) standardized work flow and responsibility, and (4) automated forwarding of results to providers. We measured the proportion of patients due for cholesterol testing who had it performed within 1 week of their clinic visit and the proportion of patients in our population who achieved low-density lipoprotein (LDL) cholesterol control at baseline and for 2 years after improved monitoring.

RESULTS

The proportion of visits in which cholesterol monitoring was completed when indicated improved from 80% to 98% within 8 months and was sustained for more than 1 year. The number of patients with controlled LDL (<130 mg/dL, 3.3 mmol/L) improved from 44 (71%) of 62 at the start of our project to 58 (94%) of 62 (P = .002) at an average follow-up of 24 months.

CONCLUSIONS

Using quality improvement and health information technology, we achieved sustained, reliable and efficient personalized monitoring of cholesterol and 11 other tests. This approach enabled substantial improvement in LDL cholesterol control. Structured methods of system redesign that leverage information technology systems hold promise for rapidly achieving reliable individualized care in other settings.

The clinical impact of humoral immunity in pediatric renal transplantation

The development of anti-donor humoral responses after transplantation associates with higher risks for acute rejection and 1-year graft survival in adults, but the influence of humoral immunity on transplant outcomes in children is not well understood. Here, we studied the evolution of humoral immunity in low-risk pediatric patients during the first 2 years after renal transplantation. Using data from 130 pediatric renal transplant patients randomized to steroid-free (SF) or steroid-based (SB) immunosuppression in the NIH-SNSO1 trial, we correlated the presence of serum anti-HLA antibodies to donor HLA antigens (donor-specific antibodies) and serum MHC class 1-related chain A (MICA) antibody with both clinical outcomes and histology identified on protocol biopsies at 0, 6, 12, and 24 months. We detected de novo antibodies after transplant in 24% (23% of SF group and 25% of SB group), most often after the first year. Overall, 22% developed anti-HLA antibodies, of which 6% were donor-specific antibodies, and 6% developed anti-MICA antibody. Presence of these antibodies de novo associated with significantly higher risks for acute rejection (P=0.02), chronic graft injury (P=0.02), and decline in graft function (P=0.02). In summary, antibodies to HLA and MICA antigens appear in approximately 25% of unsensitized pediatric patients, placing them at greater risk for acute and chronic rejection with accelerated loss of graft function. Avoiding steroids does not seem to modify this incidence. Whether serial assessments of these antibodies after transplant could guide individual tailoring of immunosuppression requires additional study.

Subclinical inflammation and chronic renal allograft injury in a randomized trial on steroid avoidance in pediatric kidney transplantation

Steroid avoidance is safe and effective in children receiving kidney transplants in terms of graft function and survival, but the effects on allograft histology are unknown. In this multicenter trial, 130 pediatric renal transplant recipients were randomized to steroid-free (SF; n = 60) or steroid-based (SB; n = 70) immunosuppression, and underwent renal allograft biopsies at the time of graft dysfunction and per protocol at implantation and 6, 12 and 24 months after transplantation. Clinical follow-up was 3 years posttransplant. Subclinical acute rejection was present in 10.6% SF versus 11.3% SB biopsies at 6 months (p = 0.91), 0% SF versus 4.3% SB biopsies at 1 year (p = 0.21) and 0% versus 4.8% at 2 years (p = 0.20). Clinical acute rejection was present in 13.3% SF and 11.4% SB patients by 1 year (p = 0.74) and in 16.7% SF and 17.1% SB patients by 3 years (p = 0.94) after transplantation. The cumulative incidence of antibody-mediated rejection was 6.7% in SF and 2.9% in SB by 3 years after transplantation (p = 0.30). There was a significant increase in chronic histological damage over time (p < 0.001), without difference between SF and SB patients. Smaller recipient size and higher donor age were the main risk factors for chronic histological injury in posttransplant biopsies.

Complete steroid avoidance is effective and safe in children with renal transplants: a multicenter randomized trial with three-year follow-up

To determine whether steroid avoidance in pediatric kidney transplantation is safe and efficacious, a randomized, multicenter trial was performed in 12 pediatric kidney transplant centers. One hundred thirty children receiving primary kidney transplants were randomized to steroid-free (SF) or steroid-based (SB) immunosuppression, with concomitant tacrolimus, mycophenolate and standard dose daclizumab (SB group) or extended dose daclizumab (SF group). Follow-up was 3 years posttransplant. Standardized height Z-score change after 3 years follow-up was -0.99 ± 2.20 in SF versus -0.93 ± 1.11 in SB; p = 0.825. In subgroup analysis, recipients under 5 years of age showed improved linear growth with SF compared to SB treatment (change in standardized height Z-score at 3 years -0.43 ± 1.15 vs. -1.07 ± 1.14; p = 0.019). There were no differences in the rates of biopsy-proven acute rejection at 3 years after transplantation (16.7% in SF vs. 17.1% in SB; p = 0.94). Patient survival was 100% in both arms; graft survival was 95% in the SF and 90% in the SB arms (p = 0.30) at 3 years follow-up. Over the 3 year follow-up period, the SF group showed lower systolic BP (p = 0.017) and lower cholesterol levels (p = 0.034). In conclusion, complete steroid avoidance is safe and effective in unsensitized children receiving primary kidney transplants.

Primer on renal transplantation

Renal transplantation transforms chronically ill children with end stage renal disease (ESRD) into near normal resulting in improvement in nutrition, growth, neurodevelopment and quality of life, and is the goal of therapy. However, the benefits of transplantation come at a price of life-long treatment with immunosuppressive medications, increased risk of infections and malignancy. Children younger than 10 y of age have the best, and adolescents have the worst 5-y graft survival likely due to non-adherence with medications in the adolescents. Long-term complications include ongoing issues related to chronic kidney disease (CKD) and cardiovascular morbidity and mortality contributing to graft loss and shortened life expectancy, thus limiting the success of organ transplantation. Therefore, appropriate management of CKD and cardiovascular issues should be integral to the care of pediatric transplant patients. The other ongoing challenges include organ shortage, prevention and treatment of late acute rejections and chronic graft dysfunction, discovering reliable noninvasive immune monitoring tools, improving adherence, psychosocial rehabilitation, and the elusive goal of tolerance.

Acute humoral rejection in pediatric renal transplant recipients receiving steroid minimization immunosuppression

SM protocols have increasingly gained acceptance owing to their favorable side effect profile with comparable cellular rejection rates. After encountering SM patients with AHR, we performed a case-control study to identify predictors associated with AHR in this cohort. Patients with (n = 4) and without (n = 19) biopsy proven AHR on a SM regimen were compared using the Student's t-tests. The median age at transplant was 13.8 yr. Compared to controls, the AHR cohort was older (15.9 vs. 12.1 yr, p = 0.01). Children with AHR had a lower mean tacrolimus trough level and were more likely to have a sub-therapeutic trough at six months (3.5 vs. 5.5 ng/mL, p = 0.05); mean MMF doses were lower at all times points except three months in the AHR group (not statistically significant). This occurred in spite of higher MPA trough levels at all study points in the AHR group (significant at 3 [p = 0.019] and 6 [p = 0.03] months). Children receiving a SM regimen have a lower safety net and may benefit from more intensive monitoring of tacrolimus exposure. MMF dose modifications based on MPA trough determinations should be resisted in the setting of SM.

The importance of different immunosuppressive regimens in the development of posttransplant diabetes mellitus

Solid-organ transplantation is the optimal long-term treatment for most patients with end-stage organ failure. After solid-organ transplantation, short-term graft survival significantly improved (1). However, due to chronic allograft nephropathy and death with functioning graft, long-term survival has not prolonged remarkably (2). Posttransplant immunosuppressive medications consist of one of the calcineurin inhibitors in combination with mycophenolate mofetil (MMF) or azathioprine (Aza) and steroids. All of them have different adverse effects, among which posttransplant diabetes mellitus (PTDM) is an independent risk factor for cardiovascular (CV) events and infections causing the death of many transplant patients and it may directly contribute to graft failure (3). According to the criteria of the American Diabetes Association (4), diabetes mellitus (DM) is defined by symptoms of diabetes (polyuria and polydipsia and weight loss) plus casual plasma glucose concentration ≥ 11.1 mmol/L or fasting plasma glucose (FPG) ≥ 7.0 mmol/L or 2-h plasma glucose level ≥ 11.1 mmol/L following oral glucose tolerance test (OGTT). This metabolic disorder occurring as a complication of organ transplantation has been recognized for many years. PTDM, which is a combination of decreased insulin secretion and increased insulin resistance, develops in 4.9/15.9% of liver transplant patients, in 4.7/11.5% of kidney recipients, and in 15/17.5% of heart and lung transplants [cyclosporine A (CyA)/tacrolimus (Tac)-based regimen, respectively] (5). Risk factors of PTDM can be divided into non-modifiable and modifiable ones (6), among which the most prominent is the immunosuppressive therapy being responsible for 74% of PTDM development (7). Emphasizing the importance of the PTDM, numerous studies have determined the long-term outcome. On the basis of these studies, graft and patient survival is tendentiously (8) or significantly (9, 10) decreased for those developing PTDM.

Complement-fixing donor-specific antibodies identified by a novel C1q assay are associated with allograft loss

Long-term outcomes following renal transplantation remain disappointing. Recently, interest has focused on the antibody-mediated component of allograft injury and the deleterious effects of DSA. We applied a novel C1q solid-phase assay in parallel with the standard IgG SAB assay to identify DSA with the potential to activate complement by binding C1q. Among 193 consecutive renal transplants at our center, 19.2% developed de novo DSA following transplantation. Of the patients with DSA, 43% had antibodies that bound C1q in vitro [C1q+ DSA]. Patients with C1q+ DSA were more likely to develop allograft loss than patients with DSA that did not bind C1q (46.7% vs. 15%; p = 0.04); patients with C1q+ DSA were nearly six times more likely to lose their transplant than those with C1q- DSA. Additionally, patients with C1q+ DSA who underwent allograft biopsy were more likely to demonstrate C4d deposition (50% vs. 8%; p = 0.03) and meet criteria for acute rejection (60% vs. 17%; p = 0.02) when compared with patients with DSA that did not bind C1q. These data suggest that DSA with the ability to activate complement, as determined by this novel C1q assay, are associated with greater risk of acute rejection and allograft loss.

Steroid avoidance in renal transplantation

PURPOSE OF REVIEW

The recent surge in the use of steroid-avoidance protocols for pediatric renal transplant recipients has been fueled by the numerous adverse side effects of steroids and development of alternatives for successful immunosuppression. Steroid-avoidance protocols were first attempted in the adult population, and with positive outcomes, pediatrics soon followed. As more pediatric patients are placed on steroid-avoidance protocols, we must begin answering several important questions such as patient and graft outcome, safety profiles of various steroid-avoidance induction protocols, viral complications and incidence of transplant lymphoproliferative disease (PTLD), metabolic benefits, and the affect of steroid minimization on growth.

RECENT FINDINGS

Initial results from steroid-avoidance protocols show these protocols are safe and effective with improved graft survival, metabolic profiles, and linear growth without an increase in viremia or PTLD.

SUMMARY

Although initial results are promising, there is still a lack of long-term data from large, prospective randomized trials, and there is not enough data to determine the optimal steroid-avoidance protocol for pediatric renal transplant recipients.

Early steroid withdrawal in pediatric renal transplant: five years of follow-up

This prospective, comparative trial investigated the impact on mean change in height standard deviation score (SDS), acute rejection rate, and renal function of early steroid withdrawal in 96 recipients with 5 years of follow-up. Recipients under basiliximab induction and steroid withdrawal (SW: TAC/MMF; n = 55) were compared with a matched steroid control group (SC: TAC/MMF/STEROID, n = 41). SW received steroids until Day 6, SC decreased to 10 mg/m(2) within 2 months post-transplant. Five years after SW, the longitudinal growth (SDS) gain was 1.4 ± 0.4 vs. 1.1 ± 0.3 for SC group (p < 0.02). Height benefits in prepubertal and pubertal status in both groups were demonstrated in the delta growth trends (mixed model; p < 0.01). Biopsy-proven acute rejection in SW was 11% and 17.5%, SC (p: ns). Mean eGFR (ml/min/1.73 m(2)) at 5 years post-transplant was SW 80.6 ± 27.8 vs. 82.6 ± 25.1 for SC (p: ns). The death-censored graft survival rate at 1 and 5 years was 99 and 90% for SW; 98 and 96% for SC (p = ns). PTLD incidence in SW 3.3 vs. 2.5% in SC (p: ns). Five years post-transplant, early steroid withdrawal showed positive impacts on growth, stable renal function without increased acute rejection risk, and PTLD incidence.

Progressive histological damage in renal allografts is associated with expression of innate and adaptive immunity genes

The degree of progressive chronic histological damage is associated with long-term renal allograft survival. In order to identify promising molecular targets for timely intervention, we examined renal allograft protocol and indication biopsies from 120 low-risk pediatric and adolescent recipients by whole-genome microarray expression profiling. In data-driven analysis, we found a highly regulated pattern of adaptive and innate immune gene expression that correlated with established or ongoing histological chronic injury, and also with development of future chronic histological damage, even in histologically pristine kidneys. Hence, histologically unrecognized immunological injury at a molecular level sets the stage for the development of chronic tissue injury, while the same molecular response is accentuated during established and worsening chronic allograft damage. Irrespective of the hypothesized immune or nonimmune trigger for chronic allograft injury, a highly orchestrated regulation of innate and adaptive immune responses was found in the graft at the molecular level. This occurred months before histologic lesions appear, and quantitatively below the diagnostic threshold of classic T-cell or antibody-mediated rejection. Thus, measurement of specific immune gene expression in protocol biopsies may be warranted to predict the development of subsequent chronic injury in histologically quiescent grafts and as a means to titrate immunosuppressive therapy.