Renal function evaluated by measured GFR during follow-up in pediatric liver transplant recipients

Abstract:  Calcineurin inhibitors form the mainstay of immunosuppression in pediatric liver transplantation, but may cause significant nephrotoxicity. We evaluated renal function in liver transplant recipients treated with a tacrolimus-based immunosuppressive regimen. GFR was measured using 99 mTc-DTPA in patients pretransplant and annually thereafter. GFR calculated by Schwartz formula was compared with the measured values. Sixty patients who underwent 69 transplants were followed for at least one yr post-transplant (median three yr). In children over two yr of age at transplant GFR fell significantly from pretransplant (140 mL/min/1.73 m²) to one yr post-transplant (112 mL/min/1.73 m²) (p = 0.01) but thereafter there was no significant decline. In younger children the picture was confounded by maturation of renal function, but again there was no significant fall to five yr post-transplant. Although 13 (22%) patients developed renal dysfunction post-transplant, none required renal replacement therapy. cGFR correlated poorly with measured values (r = 0.21). Use of a tacrolimus-based immunosuppressive regimen is associated with an initial decline in GFR, though this picture is confounded in younger children by normal maturation of renal function. There is no further significant fall in GFR in the medium-term. The Schwartz formula is inaccurate in determining GFR in this patient group.     

Improved long-term graft function in pediatric transplant renal recipients with chronic allograft nephropathy

Abstract:  CAN is the leading cause of graft loss in pediatric renal transplant recipients. A retrospective single centre analysis of pediatric transplant patients with CAN treated with MMF in conjunction with CNI minimisation/withdrawal is reported. 35 children were successfully started on MMF. The mean age at transplant was 7.9 ± 0.1 years. MMF was introduced 3.5 ± 0.1 years after transplantation and patients were followed up for a mean of 32.2 ± 0.5 months. CAN was confirmed on biopsy in 31 patients. CNI was stopped in 23 patients at a mean time of 16.5 ± 0.6 months after MMF introduction and minimised in the remaining patients. Prior to MMF introduction, GFR was deteriorating by 21.6 ± 0.07 ml/min/1.73 m²/yr. After MMF, there was an overall improvement in GFR of 4.0 ± 0.03 ml/min/1.73 m²/yr. This was most marked in the first six months when the GFR improved by 20.8 ± 0.06 ml/min/1.73 m²/day. Mean acute rejection episode rate prior to MMF was significantly reduced after MMF introduction. MMF was discontinued in a total of 4 patients due to adverse effects. CNI minimisation/withdrawal with MMF introduction is safe and leads to significant initial improvement with subsequent stabilisation of GFR and improved long term graft survival in pediatric renal transplant recipients with CAN.     

The profile of renal function over time in a cohort of pediatric heart transplant recipients

Abstract:  To assess the burden over time of renal dysfunction in pediatric heart transplant patients using an objective measure on an annual basis for serial comparison. GFR was measured at regular interval by nuclear medicine scintigraphy. Results were analyzed in relation to age, time post-transplantation, gender, and average calcineurin-inhibitor dose for the first two months post-transplantation. Results were compared with cGFR using the Schwartz equation. A total of 91 patients (56 males) transplanted between 1990 and 2004 underwent 373 GFR measurements. Median age at transplantation was 3.3 yr (birth – 17.8). Median first GFR at 0.7 yr (0.1–4.1) post-transplant was normal (94 mL/kg/1.73 m²). Freedom from at least mild renal insufficiency was 84% and 33% at one and five years post-transplant. Females had better renal function early post-transplant (GFR 105 mL/min/1.73 m²) but an increased probability of an abnormal GFR over time. Higher calcineurin inhibitor dose in the first two months post-transplantation was associated with an increasing probability of an abnormal GFR over time. The cGFR overestimated the measured GFR by 33 ± 26 mL/kg/1.73 m². Renal insufficiency is an important morbidity after pediatric transplantation with the majority of patients experiencing at least mild renal dysfunction. Calculated GFR significantly underestimates the burden of renal insufficiency in this patient population.     

Acquired cystic kidney disease before and after renal transplantation.

To determine the prevalence of acquired cystic kidney disease (ACKD), as reported in adults receiving long-term hemodialysis treatment, we studied 48 pediatric patients (aged 17 +/- 5.1 years) with end-stage renal disease by high-resolution ultrasonography or magnetic resonance imaging or both. Forty patients (83%) had a functioning renal transplant, with a mean transplant survival time of 3.4 years (range, 0.3 to 14.8 years); four patients were treated by hemodialysis and four by peritoneal dialysis. The mean duration of end-stage renal disease was 5.7 +/- 3.8 years. Ultrasonography detected ACKD in 12 (29%) of 42 patients, solitary cysts in 14 patients (33%), and no cysts in 16 patients (38%). In contrast, ACKD was diagnosed in only 3 of 37 patients studied by magnetic resonance imaging. In 31 patients studied by both imaging techniques. ACKD was diagnosed in three patients by magnetic resonance imaging but in 11 by ultrasonography. In patients with ACKD, the duration of end-stage renal disease was significantly longer, but renal (transplant) function was not different from that in patients with solitary cysts or no cysts. One patient with a history of 12 1/2 years of hemodialysis had multiple renal tumors that were diagnosed as renal cell carcinomas after bilateral nephrectomy. These results indicate that young patients with end-stage renal disease should be monitored regularly for the presence of ACKD, preferably by ultrasonography, even after successful renal transplantation.     

Intra-patient variability in tacrolimus trough concentrations and renal function decline in pediatric renal transplant recipients

Prytula AA, Bouts AH, Mathot RAA, van Gelder T, Croes LK, Hop W, Cransberg K. Intra‐patient variability in tacrolimus trough concentrations and renal function decline in pediatric renal transplant recipients. Abstract: High intra‐patient variability in TCL exposure is a risk factor for allograft loss and late acute rejection. We hypothesized that a higher intra‐patient variability leads to a faster decline in GFR in pediatric renal transplant patients and that adolescents have a higher intra‐patient variability due to poorer adherence. We included 69 children aged 3.5–18 yr who had undergone renal transplantation between April 1996 and May 2009 in two pediatric nephrology centers in the Netherlands. We analyzed TCL trough concentrations over a period of one yr and calculated TCL trough concentrations variability using VC. We investigated the correlation between the TCL trough concentrations variability and the decline in estimated GFR over four yr. The median intra‐patient variability in TCL concentrations was 30.1% (range 8.6–77.6) and the mean GFR slope ?3.8 mL/min/1.73 m²/yr. The VC correlated neither with the GFR slope, nor with the patients’ age. However, children with late acute rejection had higher VC (p = 0.045). We were unable to provide evidence that a high variability in TCL exposure leads to a faster decline in renal function, although children with late acute rejection have a higher variability in TCL exposure. Adolescents do not have a higher intra‐patient variability in TCL trough concentrations than younger children.     

Calcineurin inhibitor minimization using sirolimus leads to improved renal function in pediatric heart transplant recipients

The introduction of cyclosporine revolutionized the practice of immunosuppression for solid organ transplant recipients, and has resulted in a significant increase in survival. While CNI use has been the mainstay of immunosuppressive therapy in pediatric heart transplantation, CNIs have been associated with an increased risk of nephropathy leading to significant morbidity and mortality. We evaluated the effect on renal function of a CNI minimization protocol using SRL in pediatric heart transplant patients with CNI induced renal insufficiency. An IRB approved retrospective chart review and case control study was performed. There were 20 patients identified with renal insufficiency who had been converted to SRL (target 5-8 ng/mL) and cyclosporine (target 50-75 vs. 125-150 ng/mL). Renal insufficiency was defined as isotopic (Indium 111 DTPA) GFR <60 mL/min per 1.73 m(2) or sCr >1 mg/dL. Outcome variables evaluated were GFR and sCr at time of conversion and at two yr post conversion. Comparison was made with case control subjects matched for age at Tx, time from Tx to conversion, and initial GFR. The median age at Tx = 81 days (S.D. ±26), median time of conversion after Tx = 10 yrs (s.d. ±0.65). Self-limited/treatable side effects included hypercholesterolemia (10), neutropenia (6), aphthous ulcer (3), edema (2), anemia (2), and tremor (1). One patient rejected in the two yr prior to conversion, and one patient had two rejection episodes following conversion. GFR at conversion for study group was 51 ± 14 vs. 60 ± 2 at two yr, p = 0.018. GFR at inclusion for control group was 56 ± 20 vs. 53 ± 21, p = 0.253. This report demonstrates that minimizing CNI exposure by addition of SRL to the immunosuppressant regimen in pediatric heart transplant recipients result in improved renal function in comparison to historically managed patients. Furthermore, immunotherapy with SRL and lower-dose CNI can effectively prevent rejection with an acceptable side-effect profile.     

Risk factors for bone mineral density loss in pediatric renal transplant patients

Bone mineral density (BMD) is decreased in both adult and pediatric renal transplant recipients. To investigate the risk factors associated with this decrease in BMD post-renal transplant, we studied 33 children, aged 7-22 yr, who had received a renal transplant from 0.3 to 10 yr prior to this study. BMD analysis of the total body, spine, and femur was carried out by using dual-energy X-ray absorptiometry (DEXA). Age, weight, Tanner stage, time on dialysis prior to transplantation, cumulative corticosteroid dosage, and cyclosporin A (CsA) dosage since transplantation, and use of corticosteroid therapy prior to transplantation, were recorded. Spine, femur, and total body BMD Z-scores were greater than two standard deviations (2 SD) below the mean in 45%, 42%, and 17% of patients, respectively. Age correlated inversely with total body and spine BMD Z-scores (p = 0.001 and p = 0.008); no child under 14 yr of age had a total body or spine BMD Z-score greater than 2 SD below the mean for age. Patients at a Tanner stage of 4 or 5 had lower total body and spine BMD Z-scores than did patients at Tanner stages 1-3 (p = 0.043). Time post-transplant correlated inversely with both spine and total body BMD Z-score (p = 0.013 and p = 0.023). Only total body BMD Z-score correlated inversely with cumulative corticosteroid dose (in g, p = 0.045). BMD did not correlate with cumulative CsA dose. Black patients tended to have decreased total body BMD compared with Caucasian patients. In pediatric renal transplant patients, decreases in BMD start in adolescence. Risk factors for BMD loss in these patients include increasing age, time post-transplant, increasing Tanner stage, and ethnicity. Longitudinal studies in these patients and strategies to improve BMD are needed.     

Long‐term outcomes in pediatric liver recipients: Comparison between cyclosporin A and tacrolimus

In recent years, tacrolimus (FK506, TAC) has been increasingly utilized in liver transplantation. However, long-term risks and benefits as compared with conventional cyclosporin A (CsA) have not been fully elucidated. This retrospective study examined the potential outcome differences between TAC- and CsA-based immunosuppressive therapy in pediatric liver transplant recipients. From March 1988 to December 1996, 218 children (aged 0.1-17 yr) underwent 238 orthotopic liver transplantations; 58.7% (128/218) were under 2 yr of age at time of transplant. Initially, the maintenance immunosuppressive regimen consisted of CsA and prednisone, with antilymphocytic preparations (MALG, ATGAM, and OKT3) as induction therapy. Subsequently, TAC was used first as rescue therapy for steroid refractory rejection in CsA patients and then as maintenance immunosuppression. Fifty-seven out of the 147 CsA patients were converted to TAC for various reasons while 71 patients were placed on TAC as primary maintenance immunosuppression. 62.6 per cent (92/147) of liver recipients on CsA experienced at least one biopsy-proven acute rejection episode as compared to 50.7% (36/71) for TAC patients (p = 0.09); likewise, 34% (50/147) of CsA patients had more than one episode of rejection vs. 18.3% (13/71) for patients on TAC (p < 0.02). Rejection was the reason for conversion from CsA to TAC in 29 of 57 patients. Conversely, 19.0% (28/147) of CsA patients had to be switched to TAC for reasons not related to rejection (i.e. side-effects). The overall incidence of histologically proven chronic rejection was 7.8% (17/218). 10.9 per cent (16/147) of the children who were on CsA initially developed chronic rejection, which was significantly higher compared with one of 71 TAC recipients (p < 0.02). Of these 16 CsA patients with chronic rejection, 50.0% (8/16) underwent retransplantation for graft failure (mean interval from time of diagnosis of chronic rejection to re-transplant, 4.0 months; range 1-8 months), whereas the TAC patient has remained clinically stable with normal liver function tests after 23 months of follow-up. One year after liver transplantation, 72.8% (107/147) of CsA patients were still on steroids (mean dosage 0.20 mg/kg/d), as compared to 42.3% (30/71) of the TAC patients (mean dosage 0.14 mg/kg/d). The incidence of post-transplant lymphoproliferative disorder (PTLD) in Epstein-Barr virus (EBV)-infected patients was 2.2% (2/90), 7.0% (5/71) and 12.3% (7/57) for CsA, primary and TAC-converted groups, respectively. The overall incidence of PTLD was 6.9% (15/218). In summary, pediatric liver transplant recipients treated with TAC as primary maintenance immunosuppressive medication experienced significantly fewer episodes of rejection; especially chronic rejection, which lead to graft loss. However, the trade-off is a potential increased incidence of EBV-related PTLD in these patients.     

Ocular complications in children and adolescents following renal transplantation

Krause I, Snir M, Cleper R, Fraser A, Kovalski Y, Axer Siegel R, Bar-Nathan N, Davidovits M. Ocular complications in children and adolescents following renal transplantation.
Pediatr Transplantation 2010: 14: 77–81. © 2009 Wiley Periodicals, Inc.
Abstract:  Ocular complications after renal transplantation are common in adults. Nevertheless, data regarding these complications in children are insufficient. The purpose of the present study was to assess ocular morbidity in pediatric renal graft recipients. A retrospective observational study of 71 patients aged 11.2 ± 5.5 yr was conducted. Mean duration of follow-up was 5.6 ± 3.5 yr. A total of 16 ocular complications were found in 12 (17%) of the patients. Three patients suffered from more than one complication. Cataract was the most common finding (six patients, 8.4%) followed by swollen disk and hypertensive retinopathy in four patients (5.7%) each and increased intra-ocular pressure in two patients (3%). Mean time interval between transplantation and occurrence of first abnormal ocular finding was 37 ± 34.5 months. The follow-up time was significantly longer in patients with ophthalmological problems than in those without complications (7.8 yr vs. 5.2 yr, p < 0.02). No statistically significant association was found between the occurrence of ocular complications and the age of the patients at transplantation, donor source, duration of dialysis prior to transplantation, previous corticosteroid therapy or presence of acute rejection episodes. The results of the study point to the importance of regular concurrent ophthalmological follow-up in pediatric renal graft recipients to reduce/prevent ocular morbidity.     

Long-term glomerular filtration rate following pediatric liver transplantation

In adult patients a significant proportion of chronic renal failure after liver transplantation (LTX) has been described. This was attributed mainly to nephrotoxicity caused by Calcineurin inhibitors (CNI). If these results are transferable to pediatric patients was the aim of this study. Forty-five pediatric patients with a LTX performed between 1988 and 2003 were evaluated. Glomerular filtration rate was calculated using the Schwartz formula (calculated GFR (cGFR) (mL/min/1.73 m2) = kx height (cm)/serum creatinine (mg/dL)). Median age at LTX was 4 yr (range 0.3-18.1). Pretransplant median cGFR was significantly elevated with 157.5 mL/min/1.73 m2. Within the first 3 months after LTX median cGFR normalized to a median value of 102.7 (p < 0.05 vs. pretransplant cGFR). During long-term follow-up median cGFR remained stable with calculated values of 108.0 two years and 112.6 five years after transplantation. Using a linear and an exponential one compartment mathematical modeling of renal function the calculated GFR was stable even for very long observation times (n > 10 yr). Liver insufficiency prior to transplantation was associated with glomerular hyperfiltration. After successful liver transplantation cGFR normalized within the first 3 month and, in contrast to the reported GFR impairment in adult liver transplant recipients, remained stable, even in long-term follow-up.     

Single‐center experience in pediatric renal transplantation using thymoglobulin induction and steroid minimization

Our center has offered thymoglobulin induction with steroid minimization to our pediatric renal transplant patients for the last 10 yr. Steroid minimization or avoidance has shown favorable results in survival, kidney function, and growth in previous studies of pediatric patients. We report our experience with this protocol over the past 10 yr with respect to patient/graft survival, acute rejection episodes, renal function, linear growth, bone density, cardiovascular risk factors, and opportunistic infections. A retrospective chart review was performed for pediatric renal transplant patients on the steroid‐minimized protocol between January 2002 and December 2011 on an intention to treat basis. Patient demographics, height, weight, serum creatinine, iGFR, biopsies, and survival data were collected. Height and weight z‐scores were calculated with EpiInfo 7, using the CDC 2000 growth charts. Survival was calculated using Kaplan–Meier analysis. eGFR was calculated using the original and modified Schwartz equations. Forty‐four pediatric patients were identified, aged 13 months to 19 yr. Five‐yr survival was 95.5% for males and 94.4% for females. Only five patients had biopsy‐proven ACR, two of which were at more than 12 months post‐transplantation. Height delta z‐scores from transplant to one, three, and five yr were 0.34, 0.38, and 0.79, respectively. Weight delta z‐scores from transplant to one, three, and five yr were 0.87, 0.79, and 0.84, respectively. Mean original Schwartz eGFR was 84.3 ± 15.8 mL/min/1.73 m², modified Schwartz eGFR was 59.3 ± 11.5 mL/min/1.73 m², and iGFR was 64.2 ± 8.5 mL/min/1.73 m² at three yr. Of 18 subjects who had a bone density exam, none had a z‐score less than ?2 on DEXA exam at one‐yr post‐transplantation. Fifty‐one percent of patients were on antihypertensives at the time of transplant compared with 43% at one‐yr post‐transplantation. Three yr post‐transplantation, the average LDL was <100 mg/dL, and average total cholesterol was <200 mg/dL. There were no clinical episodes of EBV or CMV infection. A steroid‐minimized protocol with thymoglobulin induction is safe and provides favorable improvement in linear growth, stable graft function, stable or improved cardiovascular risk factors, and normal bone density in pediatric renal transplant patients.     

Protocol biopsy‐driven interventions after pediatric renal transplantation

Kanzelmeyer NK, Ahlenstiel T, Drube J, Froede K, Kreuzer M, Broecker V, Ehrich JHH, Melk A, Pape L. Protocol biopsy‐driven interventions after pediatric renal transplantation.
Pediatr Transplantation 2010: 14:1012–1018 © 2010 John Wiley & Sons A/S. Abstract: The therapeutic value of protocol biopsies (PBs) in renal transplant recipients remains unclear. We performed protocol biopsies in 57 children six months after transplantation. We increased the CNI dose in patients with borderline findings. In cases of Banff grade Ia, six prednisolone IV‐pulses were given and the CNI dose was increased. CNI toxicity and polyomavirus nephropathy led to a reduction in the CNI dose. GFR was compared with a control group of 51 children with no PBs transplanted in the same period. Forty‐two percent of PBs had no pathological changes, 24% IF/TA. Borderline findings were detected in 11%, Banff grade Ia in 15% (CNI), toxicity in 8%, and one case showed polyomavirus nephropathy. GFR after 1.5 and 2.5 yr was similar in both groups. GFR 3.5 yr after transplantation was significantly higher in the intervention group (57 ± 17 vs. 46 ± 20). Patients treated with low‐dose CNI and everolimus had a significantly lower number of pathological findings in PBs. The performance of protocol biopsies followed by a standardized treatment algorithm led to better graft function 3.5 yr after transplantation. Prospective randomized studies to confirm our findings are needed.     

Towards minimizing immunosuppression in pediatric liver transplant recipients

Abstract:  Immunosuppression regimens after liver transplantation focus mainly on preventing rejection and subsequent graft loss. However, in children, morbidity and mortality rates from infections exceed those from rejection after transplant, and immunosuppression can hinder growth, renal function, and graft tolerance. We hypothesized that early steroid withdrawal, with a primary aim of TAC monotherapy would yield no penalty in terms of rejection and graft loss, while reducing risks of infection and maximizing growth. We prospectively evaluated 64 consecutive pediatric liver transplant recipients. One yr patient/graft survival was 93/90%, respectively. At one yr post-transplant, 75.4% of patients were on TAC monotherapy. No deaths or graft losses were caused by infection. Sixty-one percent of patients had at least one episode of rejection, most within three months following transplant and 3.8% were treated for chronic rejection. One non-compliant adolescent died from chronic rejection. CMV, EBV, and lymphoproliferative disease rates were 3.1%, 5.3%, 1.8%, respectively. Pretransplant and one yr post-transplant glomerular filtration rates were unchanged. One yr improved catch-up growth was observed. We conclude that immunosuppression minimization after pediatric liver transplant yields no serious complications from rejection, and might confer advantages with respect to infection, renal function, growth, and is deserving of wider application and study.     

Alemtuzumab induction with tacrolimus monotherapy in 25 pediatric renal transplant recipients

ALA induction in transplantation has been shown to reduce the need for maintenance immunosuppression. We report the outcome of 25 pediatric renal transplants between 2007 and 2010 using ALA induction followed by tacrolimus maintenance monotherapy. Patient ages were 1–19 yr (mean 14 ± 4.1 yr). Time of follow‐up was 7–51 months (mean 26 ± 13 months). Tacrolimus monotherapy was maintained in 48% of patients, and glucocorticoids were avoided in 80% of recipients. Mean plasma creatinine and GFR at one yr post‐transplant were 0.88 ± 0.3 mg/dL and 104.4 ± 25 mL/min/1.73m², respectively. One, two, and three‐yr actuarial patient and graft survival rates were 100%. The incidence of early AR (<12 months after transplantation) was 12%, while the incidence of late AR (after 12 months) was 16%. Forty‐four percent of the recipients recovered normal, baseline renal function after an episode of AR, and 44% had persistent renal dysfunction (plasma creatinine 1.0–1.8 mg/dL). One graft was lost four yr after transplantation due to medication non‐compliance. Four (16%) patients developed BK or CMV infection. In our experience, ALA induction with tacrolimus monotherapy resulted in excellent short‐ and mid‐term patient and graft survival in low‐immunologic risk pediatric renal transplant recipients.     

The relationship between serum creatinine,serum cystatin C and glomerular filtration rate in pediatric renal transplant recipients: a pilot study

Serum cystatin C more accurately reflects glomerular filtration rate (GFR) in pediatric renal transplant recipients than serum creatinine. Nineteen pediatric renal transplant recipients, 15 male and 4 female, ranging in age from 8.35 yr to 19.06 yr (median 13.52 yr), were enrolled in the study over an 18-month period. Twenty-eight measurements of 99mTc-DTPA GFR were compared with simultaneous measurements of serum cystatin C and Cr. Linear regression analysis, Pearson correlation coefficients and analysis of variance (anova) were used to determine the relationship between creatinine, cystatin C and GFR. The correlation coefficients (R2) for the relationship of 1/Cr to DTPA-GFR and for 1/cystatin C to DTPA-GFR were 0.63 and 0.58, respectively. There was no significant difference between serum cystatin C and serum creatinine as markers of GFR. Serum cystatin C, which costs more to measure than serum creatinine, offers no advantage in monitoring the renal function of pediatric renal transplant recipients.     

Longitudinal evaluation of the pharmacokinetics of cyclosporin microemulsion (Neoral) in pediatric renal transplant recipients and assessment of C2 level as a marker for absorption

BACKGROUND: There are important differences in CsA pharmacokinetics between adult and pediatric patients, such that pharmacokinetic data can not necessarily be extrapolated from the adult to the pediatric setting. Research in adult renal transplant patients has shown that adequate cyclosporin exposure (AUC0-4) in the first week post-transplant is important for successful clinical outcome, and that cyclosporin concentration at 2 h post-dose (C2) provides the optimal single-time point marker for AUC0-4. Clinically, dose management based on C2 level results in a low incidence of acute rejection in the adult renal transplant population. The study reported here undertook pharmacokinetic profiling in de novo renal transplant patients over a period of 6 months and retrospectively assessed alternative monitoring strategies based on pharmacokinetic findings and clinical outcomes. METHODS: This open-label, observational, prospective study was carried out at four UK transplant centers over a period of 6 months in pediatric de novo renal transplant recipients receiving the microemulsion formulation of cyclosporin (Neoral) according to local protocol. Twelve-hour pharmacokinetic profiles (8-16 blood samples each) were performed on days 5 and 14 and at weeks 4, 13 and 26 post-transplant. RESULTS: Thirty-two patients were recruited (median age 10 yr, range 3-18 yr). At 6 months, patient survival was 100% and graft survival was 91%. The incidence of clinically determined acute rejection was 41% (13 of 32). Six patients discontinued Neoral before 6 months: three due to graft loss, one due to rejection, one due to renal toxicity and one due to hypertrichosis. At all time points studied, C2 correlated more closely with AUC0-4 and with AUC0-12 than did the pre-dose cyclosporin concentration (C0, or trough). Patients achieving C2 > 1.5 microg/mL by the fifth postoperative day experienced no acute rejection in the first 6 months, compared with a 50% rejection rate among patients with C2 < 1.5 microg/mL (P < 0.05). Binary logistic regression analysis showed that C2 level >1.7 microg/mL was associated with approximately 90% probability of freedom from acute rejection. Analysis of renal function across patients grouped according to cyclosporine exposure (AUC0-4, C2) showed no adverse effects of higher/increased exposure on creatinine or GFR. CONCLUSIONS: C2 level provides a more reliable marker for CsA exposure than C0 in pediatric renal transplant recipients, and is more closely predictive of acute rejection risk. A C2 target of 1.7 microg/mL appears appropriate in this population during the immediate post-transplant period in order to maximize clinical benefit.     

Multicenter trial of everolimus in pediatric renal transplant recipients: results at three year

Abstract:  There are few prospective clinical trials of mTOR inhibitors (or proliferation signal inhibitors) combined with CNI inhibitors in de novo pediatric renal transplantation. Results reported here are from a multicenter, open-label study in de novo pediatric renal transplant patients (≤16 yr), in which patients received everolimus with cyclosporine and corticosteroids for one yr, then entered an extension study for a further two yr. Nineteen patients completed the one-yr study, of whom three discontinued study medication. Fifteen of the remaining 16 patients entered the extension study, eight of whom were aged <10 yr (Group 1) and seven were aged 10–16 yr (Group 2). Mean daily dose of everolimus during the first 36 months was 1.53 mg/m² BSA. Biopsy-proven acute rejection occurred in three patients in Group 2 and in one patient in Group 1. Biopsy-proven chronic allograft rejection was reported in four patients (two in each age group). Graft survival at one yr was 100%; one patient in Group 2 lost their graft subsequently during the extension. For patients entering the extension, patient survival at three yr was 100%. There were three cases of viral infection, including one case of cytomegalovirus infection. At three yr, mean total cholesterol was 5.5 ± 0.8 m m /L (213 ± 31 mg/dL) and four patients received statin therapy. Mean serum creatinine at 36 months was 96 ± 36 μ m /L (1.1 ± 0.4 mg/dL). This is the first long-term prospective study to demonstrate that a regimen of everolimus, cyclosporine, and corticosteroids provides good efficacy, tolerability, and safety in de novo pediatric renal transplant patients.     

How to monitor renal function in pediatric solid organ transplant recipients

Abstract:  The aim is to review the tools for early detection of renal dysfunction after pediatric solid organ transplantation. Currently, the most widely used marker for detection of renal dysfunction involves measurement of GFR. Inulin clearance forms the "gold standard" method for measuring GFR; however, nuclear medicine methods (⁵¹Cr EDTA and ⁹⁹Tc DTPA isotope clearance studies) have replaced inulin clearance. The measurement of serum creatinine has a low sensitivity for the early detection of renal damage. The Schwartz formula using patient height and serum creatinine requires center-specific constants and has limitations associated with creatinine determination. These limitations may be overcome using a cystatin C-based GFR estimation. In diabetic nephropathy, and more recently in hemolytic uremic syndrome, microalbuminuria has been established as a useful screening tool for renal damage, while its predictive value in the transplantation setting needs to be established. All transplant recipients should be screened for hypertension. Early referral for ambulatory 24-h blood pressure monitoring and involvement of pediatric nephrologists should be considered. All pediatric solid organ transplant recipients receiving CNI should be screened regularly for high blood pressure and early evidence of renal damage using either GFR scans or cystatin C-based GFR estimations.     

Estimated one-yr glomerular filtration rate is an excellent predictor of long-term graft survival in pediatric first kidney transplants

Acute rejection episodes following pediatric renal transplantation have been progressively reduced by recent immunosuppressive regimens. Nevertheless, grafts continue to fail over time and surrogate parameters for long-term RGS are lacking. We investigated post-transplant renal function within the first yr as an independent predictor of long-term RGS in 104 pediatric first kidney transplant recipients (mean age 11.1 +/- 3.9 yr; mean follow-up 8.3 +/- 3.5 yr) transplanted between January 1989 and December 2000. GFR was assessed by use of the Schwartz formula at 30 days and six and 12 months after transplantation, respectively. Patients were further stratified at all times according to GFR: (i) GFR<45 mL/min/1.73 m(2), (ii) GFR 45-80 mL/min/1.73 m(2), and (iii) GFR>80 mL/min/1.73 m(2). Cox regression analysis including factors potentially influencing long-term RGS, e.g., age, gender, transplant yr, HLA-mismatch, underlying renal disease, clinical acute rejection, absolute GFR as well as the change in GFR within the first yr was performed. Graft failure occurred in 24 out of 104 patients (23%) 6.2 yr (mean) after transplantation corresponding to a cumulative five-yr graft survival of 87.5%. GFRs at 30 days and six and 12 months were significantly associated with long-term RGS in the univariate cox regression analysis (GFR at 30 days, p = 0.045; GFR at six months, p = 0.004; GFR at 12 months, p < 0.001). None of the other variables were significant parameters of correlation. Multivariate cox analysis revealed a GFR below 45 mL/min/1.73 m(2) at 12 months after transplantation as the only independent predictor of long-term RGS (hazard ratio 55.9, 95% CI 5.29-591, p = 0.001). GFR at 12 months post-transplant is an excellent surrogate parameter for long-term RGS in children. This parameter might be useful as a primary end-point in short-term pediatric clinical trials.     

De novo therapy with everolimus and reduced‐exposure cyclosporine following pediatric kidney transplantation: A prospective,multicenter, 12‐month study

Prospective data regarding the de novo use of everolimus following kidney transplantation in children are sparse. In a prospective, 12‐month, single‐arm, open‐label study, pediatric kidney transplant patients received everolimus (target trough concentration ≥3 ng/mL) with reduced‐exposure CsA and corticosteroids, with or without basiliximab induction. Sixteen of the 18 patients completed the study on‐treatment. Age range was 2–16 yr (mean 10.9 yr); eight patients received a living donor graft. Mean (s.d.) everolimus level was 7.4 (3.1) ng/mL during the first 12 months post‐transplant. There were no cases of BPAR, graft loss, or death during the study. Protocol biopsies were performed at month 12 in seven patients, with subclinical (untreated) acute rejection diagnosed in one case. Mean (s.d.) estimated GFR (Schwartz formula) was 98 (34) mL/min/1.73 m² at month 12. Three patients experienced one or more serious adverse events with a suspected relation to study medication. One patient discontinued study medication due to post‐transplant lymphoproliferative disease (5.6%). Everolimus with reduced‐dose CsA and corticosteroids achieved good efficacy and renal function and was well tolerated in this small cohort of pediatric kidney transplant patients. Controlled trials are required to answer remaining questions about the optimal use of everolimus in this setting.