Relationship Among Viremia/Viral Infection, Alloimmunity, and Nutritional Parameters in the First Year After Pediatric Kidney Transplantation.

The Immune Development in Pediatric Transplantation (IMPACT) study was conducted to evaluate relationships among alloimmunity, protective immunity, immune development, physical parameters, and clinical outcome in children undergoing kidney transplantation. We prospectively evaluated biopsy-proven acute rejection (BPAR), de novo donor-specific antibody (dnDSA) formation, viremia, viral infection, T cell immunophenotyping, and body mass index (BMI)/weight Z scores in the first year posttransplantation in 106 pediatric kidney transplant recipients. Outcomes were excellent with no deaths and 98% graft survival. Rejection and dnDSAs occurred in 24% and 22%, respectively. Pretransplant cytomegalovirus (CMV) and Epstein-Barr virus (EBV) serologies and subsequent viremia were unrelated to BPAR or dnDSA. Viremia occurred in 73% of children (EBV, 34%; CMV, 23%; BMK viremia, 23%; and JC virus, 21%). Memory lymphocyte phenotype at baseline was not predictive of alloimmune complications. Patients who developed viral infection had lower weight (-2.1) (p = 0.028) and BMI (-1.2) (p = 0.048) Z scores at transplantation. The weight difference persisted to 12 months compared with patients without infection (p = 0.038). These data indicate that there is a high prevalence of viral disease after pediatric kidney transplantation, and underweight status at transplantation appears to be a risk factor for subsequent viral infection. The occurrence of viremia/viral infection is not associated with alloimmune events.

A peripheral blood diagnostic test for acute rejection in renal transplantation.

Monitoring of renal graft status through peripheral blood (PB) rather than invasive biopsy is important as it will lessen the risk of infection and other stresses, while reducing the costs of rejection diagnosis. Blood gene biomarker panels were discovered by microarrays at a single center and subsequently validated and cross-validated by QPCR in the NIH SNSO1 randomized study from 12 US pediatric transplant programs. A total of 367 unique human PB samples, each paired with a graft biopsy for centralized, blinded phenotype classification, were analyzed (115 acute rejection (AR), 180 stable and 72 other causes of graft injury). Of the differentially expressed genes by microarray, Q-PCR analysis of a five gene-set (DUSP1, PBEF1, PSEN1, MAPK9 and NKTR) classified AR with high accuracy. A logistic regression model was built on independent training-set (n = 47) and validated on independent test-set (n = 198)samples, discriminating AR from STA with 91% sensitivity and 94% specificity and AR from all other non-AR phenotypes with 91% sensitivity and 90% specificity. The 5-gene set can diagnose AR potentially avoiding the need for invasive renal biopsy. These data support the conduct of a prospective study to validate the clinical predictive utility of this diagnostic tool.

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.

Pharmacokinetics, pharmacodynamics, safety, and tolerability of single-dose fingolimod (FTY720) in adolescents with stable renal transplants.

Oral fingolimod signals the sphingosine 1-phosphate receptor and this in turn mediates immunomodulatory activity. No data of fingolimod in any pediatric population existed before this study. We put our study results in perspective against data from adult renal transplant patients. We investigated pharmacokinetics and pharmacodynamics of single-dose fingolimod (0.07 mg/kg) and its effects on lymphocytes and heart rate in seven adolescents (14.1 ± 1.6 yr) with stable renal transplants. Blood samples for pharmacokinetics and lymphocytes were collected at screening, baseline, and up to 28 days post-dosing. Cardiac monitoring included 12-lead ECG, 24-h Holter monitoring, and echocardiography. A fingolimod dose of 0.07 mg/kg resulted in mean AUC of 731 ± 240 ng·h/mL and C(max) of 3.6 ± 0.6 ng/mL. Drug exposure was nearly identical to adults receiving the same dose. Absolute lymphocyte count decreased 85% from baseline; average nadir occurred by six h post-dose. Heart rate decreased from 74 bpm (predose mean) to 53 bpm (nadir) three h post-dose. Mean heart rates recovered by Day 14 (75 bpm). Weight-adjusted doses of fingolimod in adolescents resulted in drug exposure similar to adults. Adolescents and adults shared comparable negative chronotropic effects and decreased lymphocyte count. Recovery trajectories of these parameters back to baseline were similar between age groups.

Pharmacokinetics of oral valganciclovir solution and intravenous ganciclovir in pediatric renal and liver transplant recipients.

In an open-label, prospective, pharmacokinetic assessment, we evaluated total drug exposure (area under the curve [AUC]) of intravenous (IV) ganciclovir (GCV) and oral (p.o.) valganciclovir when normalized for body surface area (BSA) in pediatric liver (n=20) and renal (n=26) transplant patients Reference doses for IV GCV (200 mg/m(2)) and p.o. valganciclovir (520 mg/m(2)) were based on adult doses, and adjusted for BSA initially, and BSA and renal function (estimated via creatinine clearance [CrCL]) thereafter. Renal transplant patients received GCV on days 1-2, valganciclovir 260 mg/m(2) on day 3, and valganciclovir 520 mg/m(2) on day 4. Liver transplant patients received twice daily GCV from enrollment to day 12, and then valganciclovir twice daily on days 13-14. GCV pharmacokinetics were described using a population pharmacokinetic approach. Type of solid organ transplant (kidney or liver) had no effect on GCV pharmacokinetics. Median GCV exposure following valganciclovir 520 mg/m(2) was similar to that with IV GCV, and to that reported in adults. Patients <5 years of age had AUC values approximately 50% of those compared with older age ranges; dosing based on both BSA and CrCL increased drug exposure in younger patients. A dosing algorithm based on BSA and CrCL should be tested in future studies.

Valganciclovir dosing according to body surface area and renal function in pediatric solid organ transplant recipients.

Oral valganciclovir is effective prophylaxis for cytomegalovirus (CMV) disease in adults receiving solid organ transplantation (SOT). However, data in pediatrics are limited. This study evaluated the pharmacokinetics and safety of valganciclovir oral solution or tablets in 63 pediatric SOT recipients at risk of CMV disease, including 17 recipients < or =2 years old. Patients received up to 100 days' valganciclovir prophylaxis; dosage was calculated using the algorithm: dose (mg) = 7 x body surface area x creatinine clearance (Schwartz method; CrCLS). Ganciclovir pharmacokinetics were described using a population pharmacokinetic approach. Safety endpoints were measured up to week 26. Mean estimated ganciclovir exposures showed no clear relationship to either body size or renal function, indicating that the dosing algorithm adequately accounted for both these variables. Mean ganciclovir exposures, across age groups and organ recipient groups were: kidney 51.8 +/- 11.9 microg * h/mL; liver 61.7 +/- 29.5 microg * h/mL; heart 58.0 +/- 21.8 microg * h/mL. Treatment was well tolerated, with a safety profile similar to that in adults. Seven serious treatment-related adverse events (AEs) occurred in five patients. Two patients had CMV viremia during treatment but none experienced CMV disease. In conclusion, a valganciclovir-dosing algorithm that adjusted for body surface area and renal function provides ganciclovir exposures similar to those established as safe and effective in adults.

Nonadherence consensus conference summary report.

This report is a summary of a 'Consensus Conference' on nonadherence (NA) to immunosuppressants. Its aims were: (1) to discuss the state-of-the-art on the definition, prevalence and measurement of NA, its risk factors and impact on clinical and economical outcomes and interventions and (2) to provide recommendations for future studies. A two-day meeting was held in Florida in January 2008, inviting 66 medical and allied health adherence transplant and nontransplant experts. A scientific committee prepared the meeting. Consensus was reached using plenary and interactive presentations and discussions in small break-out groups. Plenary presenters prepared a summary beforehand. Break-out group leaders initiated discussion between the group members prior to the meeting using conference calls and e-mail and provided a summary afterward. Conclusions were that NA: (a) is more prevalent than we assume; (b) is hard to measure accurately; (c) tends to confer worse outcomes; (d) happens for a number of reasons, and system-related factors including the patient's culture, the healthcare provider and the setting and (e) it is not currently known how to improve adherence. This consensus report provided some roadmaps for future studies on this complicated, multifaceted problem.

Should pediatric patients wait for HLA-DR-matched renal transplants?

Graft survival rates from deceased donors aged 35 years or less among all primary pediatric kidney transplant recipients in the United States between 1996 and 2004 were retrospectively examined to determine the effect of HLA-DR mismatches on graft survival. Zero HLA-DR-mismatched kidneys had statistically comparable 5-year graft survival (71%), to 1-DR-mismatched kidneys (69%) and 2-DR-mismatched kidneys (71%). When compared to donors less than 35 years of age, the relative rate of allograft failure was 1.32 (p = 0.0326) for donor age greater than or equal to age 35. There was no statistical increase in the odds of developing a panel-reactive antibody (PRA) greater than 30% at the time of second waitlisting, based upon the degree of HLA-A, -B or -DR mismatch of the first transplant, nor was there a 'dose effect' when more HLA antigens were mismatched between the donor and recipient. Therefore, pediatric transplant programs should utilize the recently implemented Organ Procurement and Transplantation Network's (OPTN)allocation policy, which prioritizes pediatric recipients to receive kidneys from deceased donors less than 35 years of age, and should not turn down such kidney offers to wait for a better HLA-DR-matched kidney.

Pediatric transplantation in the United States, 1996-2005.

Solid organ transplantation is accepted as a standard lifesaving therapy for end-stage organ failure in children. This article reviews trends in pediatric transplantation from 1996 to 2005 using OPTN data analyzed by the Scientific Registry of Transplant Recipients. Over this period, children have contributed significantly to the donor pool, and although the number of pediatric donors has fallen from 1062 to 900, this still accounts for 12% of all deceased donors. In 2005, 2% of 89,884 candidates listed for transplantation were less than 18 years old; in 2005, 1955 children, or 7% of 28,105 recipients, received a transplant. Improvement in waiting list mortality is documented for most organs, but pretransplant mortality, especially among the youngest children, remains a concern. Posttransplant survival for both patients and allografts similarly has shown improvement throughout the period; in most cases, survival is as good as or better than that seen in adults. Examination of immunosuppressive practices shows an increasing tendency across organs toward tacrolimus-based regimens. In addition, use of induction immunotherapy in the form of anti-lymphocyte antibody preparations, especially the interleukin-2 receptor antagonists, has increased steadily. Despite documented advances in care and outcomes for children undergoing transplantation, several considerations remain that require attention as we attempt to optimize transplant management.

Medication non-adherence in the adolescent renal transplant recipient: a clinician's viewpoint.

Recent advancements in immunosuppression and surgical techniques have significantly improved the outcome of kidney transplantation in the pediatric population. Adolescents enjoy the best 1-year graft survival of any age group. However, the long-term transplant outcome in adolescents is disappointing. Non-adherence with immunosuppressive medications is one of the most important contributing factors for graft rejection and loss in teenagers. The impact of non-adherence is perceived to be far more powerful in adolescent transplant recipients than in the transplant population as a whole. To better understand adolescent non-adherence, the process of transplantation must be placed in the context of adolescent development. Adolescents try to establish their identity and autonomy separately from the parents; however at the same time, adolescents with chronic illness require help, support and guidance from adults, including parents and medical personnel. Adolescents have limited ability to anticipate abstractly the long-term consequences of their immediate actions. This inconsistency can create frustration in both adolescents and in the supporting systems around them. Despite the significant consequences of adolescent non-adherence, research in this area is scarce. There are still no established definitions, standardized diagnostic methods and effective interventions to treat and prevent this problem. We propose the recommendations to approach the problems of adolescent transplant non-adherence from the transplant clinician's viewpoint. With early identification and appropriate interventions, significant improvement in adolescent graft survival is possible.

Single-dose pharmacokinetics and tolerability of everolimus in stable pediatric renal transplant patients.

Everolimus (Certican; RAD), a novel macrolide with potent immunosuppressive and anti-proliferative activities, prevents acute rejection in adult recipients of renal transplantation. This phase I trial conducted in stable pediatric renal transplant patients examined the single-dose pharmacokinetics, safety, and tolerability of everolimus in combination with cyclosporin A (CsA; Neoral) and corticosteroids, with or without azathioprine. Nineteen pediatric patients were enrolled and received a single 1.2 mg/m2 dose of everolimus. Everolimus was safe and well tolerated, with a low incidence of adverse events reported and none judged to be related to the study medication. Everolimus administration did not increase infection rates or produce clinically significant changes in vital signs or changes in electrocardiograms. Apparent clearance and volume of distribution of everolimus increased with age, weight, and body surface area in a generally linear manner across the pediatric demographic ranges. Compared with adults from a previous study, apparent clearance (L/h) and distribution volume (L) were lower in pediatric patients, whereas the elimination half-life was similar. Single-dose everolimus co-administration did not affect the steady-state pharmacokinetics of CsA. Based on this information, pediatric patients will need a dose scaled down for body size, but can probably maintain the same twice-daily dosing schedule used in adults.

Safety and efficacy of TOR inhibitors in pediatric renal transplant recipients.

Information about the pharmacokinetics, safety, and efficacy of target of rapamycin (TOR) inhibitors, such as sirolimus and everolimus, in pediatric renal transplant recipients is limited. In an ascending single-dose pharmacokinetic study of sirolimus in pediatric dialysis patients, no clinically significant association was observed between patient age and absorption of sirolimus from the gastrointestinal tract. However, young pediatric patients (5 to 11 years of age) exhibited significantly greater apparent oral clearances, suggesting that pediatric patients require slightly higher doses than do adults when adjusted for body weight or surface area. Similarly, in studies performed in pediatric renal transplant recipients, the half-life of sirolimus was shorter and the clearance was greater in younger patients. On the other hand, in single-dose pharmacokinetic studies of everolimus, the apparent clearance was reduced in pediatric renal transplant recipients compared with clearance in adults. This reduced clearance was attributed to a smaller apparent volume of distribution in pediatric patients, rather than to a difference in terminal half-life. This suggested that, although the adult 12-hour dosing interval was appropriate for pediatric patients, they would require reduced dosing based on body size compared with adults. In a large trial (N = 719) of sirolimus versus azathioprine in combination with cyclosporine microemulsion and prednisone, 6 pediatric patients (13 to 18 years of age) received sirolimus at 2 mg/d, 3 received sirolimus at 5 mg/d, and 3 received azathioprine. Seven of the nine patients who received sirolimus experienced no rejection episodes. Six infectious episodes occurred in the 6 patients receiving sirolimus at 2 mg/d, 10 episodes occurred in the 3 patients receiving sirolimus at 5 mg/d, and 8 episodes occurred in the 3 patients receiving azathioprine. At 6 months after transplantation, renal function was similar in all 3 groups, although there was a statistically nonsignificant increase in the group receiving sirolimus at 5 mg/d. The mean cholesterol and triglyceride levels were generally comparable in all 3 groups. TOR inhibitors are promising agents for the prevention of graft rejection in pediatric renal transplant recipients, but more pharmacokinetic data are required to assess the optimal dosing regimens in this population. In addition, further data are needed on the efficacy and safety of TOR inhibitors in combination with other agents in pediatric transplantation recipients to best assess the role of TOR inhibition in corticosteroid and/or calcineurin inhibitor-sparing regimens.

Immediate post-transplant nephrosis in a patient with congenital nephrotic syndrome.

A 19-month-old girl with congenital nephrotic syndrome of the Finnish type underwent a living-related renal transplant; 24 h after transplantation she became massively nephrotic. She did not respond to steroids, plasmapheresis, and high-dose cyclosporine. A month later, a renal biopsy showed only glomerular foot process effacement. She was treated with high-dose methylprednisolone pulses and oral cyclophosphamide. She rapidly went into complete remission with no further relapses. Graft function has been stable 2 years after transplantation.

The use of mycophenolate mofetil suspension in pediatric renal allograft recipients.

Mycophenolate mofetil (MMF) is widely used to prevent acute rejection in adults after renal, cardiac, and liver transplantation. This study investigated the safety, tolerability, and pharmacokinetics of MMF suspension in pediatric renal allograft recipients. One hundred renal allograft recipients were enrolled into three age groups (33 patients, 3 months to <6 years; 34 patients, 6 to <12 years; 33 patients, 12 to 18 years). Patients received MMF 600 mg/m2 b.i.d. concomitantly with cyclosporine and corticosteroids with or without antilymphocyte antibody induction. One year after transplantation, patient and graft survival (including death) were 98% and 93%, respectively. Twenty-five patients (25%) experienced a biopsy-proven (Banff grade borderline or higher) or presumptive acute rejection within the first 6 months post-transplantation. Analysis of pharmacokinetic parameters for mycophenolic acid (MPA) and mycophenolic acid glucuronide showed no clinically significant differences among the age groups. The dosing regimen of MMF 600 mg/m2 b.i.d. achieved the targeted early post-transplantation MPA 12-h area under concentration-time curve (AUC0-12) of 27.2 microg h per ml. Adverse events had similar frequencies among the age groups (with the exception of diarrhea, leukopenia, sepsis, and anemia, which were more frequent in the <6 years age group) and led to withdrawal of MMF in about 10% of patients. Administration of MMF 600 mg/m2 b.i.d. is effective in prevention of acute rejection, provides predictable pharmacokinetics, and is associated with an acceptable safety profile in pediatric renal transplant recipients.

Comparison of mortality in all patients on dialysis, patients on dialysis awaiting transplantation, and recipients of a first cadaveric transplant.

BACKGROUND AND METHODS: The extent to which renal allotransplantation - as compared with long-term dialysis - improves survival among patients with end-stage renal disease is controversial, because those selected for transplantation may have a lower base-line risk of death. In an attempt to distinguish the effects of patient selection from those of transplantation itself, we conducted a longitudinal study of mortality in 228,552 patients who were receiving long-term dialysis for end-stage renal disease. Of these patients, 46,164 were placed on a waiting list for transplantation, 23,275 of whom received a first cadaveric transplant between 1991 and 1997. The relative risk of death and survival were assessed with time-dependent nonproportional-hazards analysis, with adjustment for age, race, sex, cause of end-stage renal disease, geographic region, time from first treatment for end-stage renal disease to placement on the waiting list, and year of initial placement on the list. RESULTS: Among the various subgroups, the standardized mortality ratio for the patients on dialysis who were awaiting transplantation (annual death rate, 6.3 per 100 patient-years) was 38 to 58 percent lower than that for all patients on dialysis (annual death rate, 16.1 per 100 patient-years). The relative risk of death during the first 2 weeks after transplantation was 2.8 times as high as that for patients on dialysis who had equal lengths of follow-up since placement on the waiting list, but at 18 months the risk was much lower (relative risk, 0.32; 95 percent confidence interval, 0.30 to 0.35; P<0.001). The likelihood of survival became equal in the two groups within 5 to 673 days after transplantation in all the subgroups of patients we examined. The long-term mortality rate was 48 to 82 percent lower among transplant recipients (annual death rate, 3.8 per 100 patient-years) than patients on the waiting list, with relatively larger benefits among patients who were 20 to 39 years old, white patients, and younger patients with diabetes. CONCLUSIONS: Among patients with end-stage renal disease, healthier patients are placed on the waiting list for transplantation, and long-term survival is better among those on the waiting list who eventually undergo transplantation.