Empiric switch from calcineurin inhibitor to sirolimus‐based immunosuppression in pediatric heart transplantation recipients

Sirolimus is used in heart transplant patients with CAV and CNI‐induced nephropathy. However, little is known regarding the tolerability, rejection rate, and effect on renal function when used empirically in children. We describe our experience with the empiric use of a sirolimus‐based immunosuppressive regimen in pediatric heart transplantation recipients. We reviewed records of patients in whom conversion was attempted to a CNI‐free sirolimus‐based regimen. Rejection episodes and measures of renal function were recorded. We attempted to convert 20 patients, of which 16 were successful. In total, six of 20 patients (30%) experienced adverse effects. Of the 16 converted, four patients converted to sirolimus due to CNI‐induced disease (three nephropathy, one CAV), while 12 patients (mean age 5.5 yr, range 0.1–21 yr; 33% female; 33% with a history of congenital heart disease) were empirically switched to sirolimus at a mean of 2.3 yr after transplant. Follow‐up was available for a mean of 2.5 yr after conversion (range 0.5–8.3 yr). The rate of rejection while taking CNIs was 0.18 rejection episodes per patient‐year (total of five episodes), compared with 0.03 rejection episodes per patient‐year (total of one episode) while on sirolimus. Renal function, in terms of GFR, significantly improved after sirolimus conversion at latest follow‐up (from 86 ± 37 mL/min to 130 ± 49 mL/min, p = 0.02). Here, we demonstrate the potential benefit of empiric use of sirolimus in pediatric heart transplant patients in a CNI‐free regimen. Larger and longer studies are needed to further clarify risks of rejection and adverse effect profiles.     

Prope tolerance after pediatric liver transplantation

pT, under mono‐ and infratherapeutic calcineurin inhibition, may constitute an optimal condition combining graft acceptance with low IS load and minimal IS‐related toxicity. We reviewed 171 pediatric (<15.0 yr) survivors beyond one yr after LT, transplanted between April 1999 and June 2007 under tacrolimus‐based regimens (median follow‐up post‐LT: 6.0 yr, range: 0.8–9.5 yr). Their current status regarding IS therapy was analyzed and correlated with initial immunoprophylaxis. pT was defined as tacrolimus monotherapy, with mean trough blood levels <4 ng/mL during the preceding year of follow‐up, combined with normal liver function tests. The 66 children transplanted before April 2001 received a standard tacrolimus–steroid regimen. Beyond April 2001, 105 patients received steroid‐free tacrolimus–basiliximab or tacrolimus–daclizumab immunoprophylaxis. In the latter group, 43 (41%) never experienced any acute rejection episode and never received steroids. In the long term, a total of 79 recipients (47%) developed pT (n = 73) or IS‐free operational tolerance (n = 6), 27 of them belonging to the 43 steroid‐free patients (63%). In contrast, only 52/128 (41%) children treated with steroids subsequently developed prope/operational tolerance (p = 0.012). Steroid‐free tacrolimus‐based IS seems to promote long‐term graft acceptance under minimal/no IS. These results constitute the first evidence that minimization of IS, including steroid avoidance, might be tolerogenic in the long term after pediatric LT.     

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.     

Angiotensin II type 1 receptor antibodies in childhood kidney transplantation

Angiotensin II type 1 receptor antibodies (AT₁RAb) have emerged as non‐HLA Ab present in patients with acute AMR and risk of graft loss. Furthermore, AT₁RAb have been shown to increase angiotensin II sensitivity which may play a role in the development of CVD and hypertension. Data on AT₁RAb in stable transplant recipients are lacking. The aim of this study was to analyze the levels of AT₁RAb in a cohort of stable patients after kidney transplantation (tx) in childhood. A cross‐sectional study of 30 children (median age 14, range 3–19 yr, median time since tx five yr) and 28 adults who were transplanted in childhood (median age 26, range 20–40 yr, median time since tx 18 yr) transplanted between 1993–2006 and 1983–2002, respectively, was performed. Healthy controls were 51 healthy children (5–8 yr) and 199 healthy donors (median age 56.5 yr, range 42–83 yr). Plasma AT₁RAb were analyzed by immunoassay. Median total AT₁RAb IgG concentration was significantly higher in the pediatric‐tx group as compared to the adult‐tx group (40.0 and 10.95 U/mL, p < 0.0001). For both groups, the tx group showed higher levels: the pediatric‐tx group vs. control group (40.0 vs. 13.3 U/mL, p = 0.0006) and the adult‐tx group vs. adult control group (10.95 vs. 6.5 U/mL, p < 0.0001). Age was the strongest indicator of high levels of AT₁RAb IgG (p = 0.0003). AT₁RAb total IgG levels are significantly higher in a stable pediatric‐tx cohort as compared to adult‐tx patients and healthy controls of comparable age groups. The relevance of our findings in relation to age, time since tx, previous or future rejection, and CVD risk merits future studies.     

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.     

Medication adherence in the transition of adolescent kidney transplant recipients to the adult care

Non‐adherence is common in adolescent and young adult kidney transplant recipients, leading to adverse graft outcomes. The aim of this study was to determine whether adherence to immunosuppressant medications changes during transition from a pediatric to an adult program within the same transplant center. Adherence was assessed for a period of two yr before and two yr after the transfer. Subtherapeutic trough levels of serum tacrolimus and level variability were used as measures of adherence. Twenty‐five patients were transitioned between 1996 and 2011 at the median age of 22.3 [IQR 21.6–23.0] yr. Young adults 21–25 yr of age (n = 26) and non‐transitioned adolescents 17–21 yr of age (currently followed in the program, n = 24 and those that lost their grafts prior to the transfer, 22) formed the comparison groups. In the transitioned group, adherence prior to the transfer was not significantly different from the adherence after the transfer (p = 0.53). The rate of non‐adherence in the group of non‐transitioned adolescents who lost their grafts (68%) was significantly higher than in the transitioned group (32%, p = 0.01). In the group of young adults, adherence was not significantly different from the transitioned group (p = 0.27). Thus, transition was not associated with differences in medication adherence in this single‐center study. Large‐scale studies are needed to evaluate the national data on medication adherence after transfer.     

Mortality after pediatric kidney transplantation in England – a population‐based cohort study

The aim of this study was to explore mortality after pediatric kidney transplantation in England over the last decade. We used data from HES to select all kidney transplant procedures performed in England between April 2001 and March 2012. Data linkage analysis was performed with the ONS to identify all deaths occurring among this study cohort. Data for 1189 pediatric recipients were compared to 17 914 adult recipients (number of deaths, 33 vs. 2052, respectively, p < 0.001), with median follow‐up 4.4 yr (interquartile range 2.2–7.3 yr). There was no difference in mortality within the pediatric cohort; age 0–1 (n = 25, patient survival 100.0%), age 2–5 (n = 198, patient survival 96.0%), age 6–12 (n = 359, patient survival 97.5%), and age 13–18 (n = 607, patient survival 97.4%), respectively (p = 0.567). The most common causes of death were renal (n = 8, 24.2%), infection (n = 6, 18.2%), and malignancy (n = 5, 15.2%). All deaths from malignancy were secondary to PTLD. In a fully adjusted Cox regression model, only white ethnicity was significantly associated with risk of pediatric mortality post‐kidney transplantation (hazard ratio 2.7, 95% confidence interval [1.0–7.3], p = 0.047). To conclude, this population‐based cohort study confirms low mortality after pediatric kidney transplantation with short follow‐up.     

Basiliximab with delayed introduction of calcineurin inhibitors as a renal‐sparing protocol following liver transplantation in children with renal impairment

Renal impairment is frequently compromised in patients with end‐stage liver disease and is associated with increased long‐term mortality post‐LT. In contrast to CNI, basiliximab is an immunosuppressive agent with minimal nephrotoxic potential. This study reviews the experience of a single pediatric liver transplant center's renal‐sparing approach with the use of basiliximab and MMF to compensate for delayed entry of CNI in children with renal impairment at the time of organ availability. There were no differences in renal function between pediatric patients with and without pre‐LT renal impairment within the first year (cGFR: 135 mL/min/1.73 m² vs. 144 mL/min/1.73 m²; p = 0.56) or at 5–8 yr following LT, (129 mL/min/1.73 m² vs. 130 mL/min/1.73 m²; p = 0.97). In addition, there was no difference in ACR rates (50% vs. 43%, p = 0.62) between patients in the basiliximab group and those patients receiving standard CNI and steroid strategies. The utilization of a renal‐sparing approach with basiliximab alongside delayed entry and lower early target trough levels of CNI in children with renal impairment at the time of LT is safe and maintains excellent long‐term kidney function.     

Neurocognitive outcomes at kindergarten entry after liver transplantation at <3 yr of age

This prospective inception cohort study determines kindergarten‐entry neurocognitive abilities and explores their predictors following liver transplantation at age <3 yr. Of 52 children transplanted (1999–2008), 33 (89.2%) of 37 eligible survivors had psychological assessment at age 54.7 (8.4) months: 21 with biliary atresia, seven chronic cholestasis, and five acute liver failure. Neurocognitive scores (mean [s.d.], 100 [15]) as tested by a pediatric‐experienced psychologist did not differ in relation to age group at transplant (≤12 months and >12 months): FSIQ, 93.9 (17.1); verbal (VIQ), 95.3 (16.5); performance (PIQ), 94.3 (18.1); and VMI, 90.5 (15.9), with >70% having scores ≥85, average or above. Adverse predictors from the pretransplant, transplant, and post‐transplant (30 days) periods using univariate linear regressions for FSIQ were post‐transplant use of inotropes, p = 0.029; longer transplant warm ischemia time, p = 0.035; and post‐transplant highest serum creatinine, (p = 0.04). For PIQ, they were pretransplant encephalopathy, p = 0.027; post‐transplant highest serum creatinine, p = 0.034; and post‐transplant inotrope use, p = 0.037. For VMI, they were number of post‐transplant infections, p = 0.019; post‐transplant highest serum creatinine, p = 0.025; and lower family socioeconomic index, p = 0.039. Changes in care addressing modifiable predictors, including reducing acute post‐transplant illness, pretransplant encephalopathy, transplant warm ischemia times, and preserving renal function, may improve neurocognitive outcomes.     

Valganciclovir dosing using area under the curve calculations in pediatric solid organ transplant recipients

Pediatric valganciclovir dosing recommendations have not been extensively validated for prevention or treatment for CMV infection. As such, we performed a pharmacokinetic study to compare different valganciclovir dosing regimens and the potential benefits of individualized dose adjustments in children following organ transplantation. Ganciclovir AUCs were calculated from four plasma drug levels in pediatric SOT recipients aged six months through three yr receiving valganciclovir suspension by mouth. Of the 28 ganciclovir AUC calculations performed, 11 (39%) were outside the therapeutic target range of 40–60 mcg h/L leading to a valganciclovir dose adjustment. Current manufacturer‐recommended dosing based on BSA and CrCl was estimated to result in therapeutic AUCs in fewer patients than the simple weight‐based formula used in our institution (4 vs. 13; p = 0.017). An AUC calculation using only the two‐ and five‐h measurements was strongly correlated with the AUC using all four time measurements (R² = 0.846; p < 0.001). A simple weight‐based dosing approach gives a higher probability for therapeutic AUCs compared to the manufacturer‐recommended dosing in pediatric transplant patients aged six months through three yr with normal renal function. An AUC calculated using two sample times might allow for fewer blood draws in the future.     

The use of renal replacement therapy in critically ill pediatric small bowel transplantation candidates and recipients: Experience from one center

Outcomes for pediatric SBT patients requiring perioperative RRT in the PICU remain unknown. The objectives were to document our center's experience with PICU SBT patients receiving perioperative RRT and to identify variables predictive of survival to discharge. A retrospective chart review of patients (ages, 0–18 yr) between January 1, 2000 and December 31, 2011 that received RRT within a SBT perioperative period and were transplanted at our university‐affiliated, tertiary care children's hospital was performed. Six SBT patients received perioperative RRT (ages, 5–12 yr). Three patients (50%) survived to hospital discharge. Among survivors, RRT was required for a total of 1–112 days (mean, 49.7 days). All three survivors survived to hospital discharge without renal transplantation and free of RRT. There was a trend toward increased survival among older patients receiving RRT (p = 0.05). Survivors had a higher I‐125 GFR prior to PICU admission (p = 0.045). A higher I‐125 GFR prior to PICU admission among survivors may support this test's utility during SBT evaluation. In our experience, a high survival rate and freedom from RRT at the time of discharge support RRT use in the SBT population.     

Parental functioning improves the developmental quotient of pediatric liver transplant recipients

Psychomotor development in pediatric liver transplant (LT) recipients depends on several factors. Our aim was to evaluate the importance of parental involvement and family dynamics on psychomotor development by assessing (i) children and parents individually, (ii) the parent–child relationship, and (iii) the correlation between parental functioning and patient outcome, all before and after LT. Age‐appropriate scales were used before and after LT. Twenty‐one patients, 19 mothers, and 16 fathers were evaluated. Developmental quotient (DQ): No subjects scored in the “very good” range. The proportion of children with deficits increased from LT to two yr: 17.6% vs. 28.6%. Subjects 0–2 yr were more likely to have normal DQ at transplant (66.7% vs. 50% for older children). Abnormal DQ was more prevalent two yr post‐LT in children older at LT (p = 0.02). The mother–child relationship was normal in 59% of families pre‐LT and in 67% at two yr. The relationship was more favorable when the child received a transplant as an infant (p = 0.014 at 12 months post‐LT). Normal DQ was associated with higher maternal global functioning score pre‐LT (p = 0.03). Paternal performance scores were higher than maternal scores. Children transplanted after two yr of age suffer greater long‐term deficits than those transplanted as infants.     

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.     

Longitudinal renal function in pediatric heart transplant recipients: 20‐years experience

This study was initiated to assess the temporal trends of renal function, and define risk factors associated with worsening renal function in pediatric heart transplant recipients in the immediate post‐operative period. We performed a single‐center retrospective study in children ≤18 yr receiving OHT (1993–2012). The AKIN's validated, three‐tiered AKI staging system was used to categorize the degree of WRF. One hundred sixty‐four patients qualified for inclusion. Forty‐seven patients (28%) were classified as having WRF after OHT. Nineteen patients (11%) required dialysis after heart transplantation. There was a sustained and steady improvement in renal function in children following heart transplantation in all age groups, irrespective of underlying disease process. The significant factors associated with risk of WRF included body surface area (OR: 1.89 for 0.5 unit increase, 95% CI: 1.29–2.76, p = 0.001) and use of ECMO prior to and/or after heart transplantation (OR: 3.50, 95% CI: 1.51–8.13, p = 0.004). Use of VAD prior to heart transplantation was not associated with WRF (OR: 0.50, 95% CI: 0.17–1.51, p = 0.22). On the basis of these data, we demonstrate that worsening renal function improves early after orthotopic heart transplantation.     

Clinical predictors of autoimmune and severe atopic disease in pediatric heart transplant recipients

Autoimmune and allergic diseases cause morbidity and diminished quality of life in pediatric organ transplant recipients. We hypothesize that younger age at transplantation and immunosuppression regimen play a role in the development of immune‐mediated disease following heart transplant. A single institution retrospective review identified all patients undergoing heart transplant at ≤18 yr of age from 1987 to 2010 who survived ≥1 yr. Using medical record and database review, patients were evaluated for development of autoimmune or severe allergic disease. Of 129 patients who met criteria, seven patients (5.4%) with autoimmune or severe atopic disease were identified. Immune‐mediated diseases included inflammatory bowel disease (n = 3), eosinophilic esophagitis/colitis (n = 4), and chronic bullous disease of childhood (n = 1). Patients <1 yr of age at transplant were at greater risk of developing autoimmune disease than patients 1–18 yr at transplant (OR = 9.3, 95% CI 1.1–79.2, p = 0.02). All affected patients underwent thymectomy at <1 yr of age (7/71 vs. 0/58, p = 0.02). In our experience, heart transplantation in infancy is associated with the development of immune‐mediated gastrointestinal and dermatologic diseases. Further study is needed to determine risk factors for the development of immune‐mediated disease to identify best practices to decrease incidence.     

Laparoscopic donor nephrectomy for the pediatric recipient population: Risk factors for adverse outcomes

Kidney transplantation is the optimal treatment of ESRD in children. Some studies have reported inferior outcomes in recipients of LDN allografts who are ≤5 yr of age. We performed a retrospective review of pediatric recipient outcomes of 110 LDN allografts at our institution and examined predictors of adverse outcomes. Subgroup analysis was performed by dividing recipients into three age categories: 0–5 yr, 6–17 yr, and ≥18 yr. There was no significant difference between incidences of DGF or ARE between groups. Kaplan–Meier analysis demonstrated 100% allograft survival in 0‐ to 5‐yr‐old recipients, nearly reaching statistical significance (p = 0.07) for outcome superior to that of the two older age groups. Pretransplant HD was associated with increased risk of DGF (p = 0.05). Significant risk factors for ARE were recipient weight >15 kg (p = 0.033) and multiple renal arteries (p = 0.047). Previous ARE was associated with an increased risk of allograft failure (p = 0.02). LDN is not associated with increased risk of DGF, ARE, or allograft failure in the youngest recipients. These findings support an aggressive pursuit of preemptive transplantation even in the youngest pediatric allograft recipients.     

Incidence and risk factors of bacterial infections in children following autologous hematopoietic stem cell transplantation: Single‐center experience from Jordan

Bacterial infection is a serious sequela following AHSCT; however, limited data are available regarding pediatric recipients, especially in developing countries. We retrospectively analyzed the incidence and risk factors of bacterial infections during the first 100 days after AHSCT in children at KHCC in Amman, Jordan between January, 2005 and September, 2013. A total of 65 patients were identified, with median age of four yr (1–17). Forty‐seven patients (72.3%) had solid tumors and 18 (27.7%) had lymphoma. Bacterial infections were documented in 33 patients (50%), with a total of 63 episodes. Gram‐negative infection (57.1%) was more prevalent than Gram‐positive infection (38%). The risk of bacterial infections was higher among patients less than five yr of age (p = 0.028) and those who developed hypogammaglobulinemia requiring IVIG replacement (p = 0.001). Patients with solid tumors developed more bacterial infections compared to patients with lymphoma (p = 0.0057). No deaths were attributed to bacterial infection. Bacterial infection rate is high among recipients of AHSCT in Jordan with Gram‐negative bacteria being the most common.     

Survival in children on extracorporeal membrane oxygenation at the time of lung transplantation

Limited data exist on ECMO at the time of LTx in children. The UNOS database was queried from 2000 to 2013 for pediatric lung transplant recipients (<18 yr) to assess post‐transplant survival of patients on ECMO at the time of LTx. Of 587 pediatric recipients with 17 on ECMO, 585 were used for univariate and Kaplan–Meier function analysis, 535 for multivariate Cox models, and 24 for propensity score matching. Univariate Cox (HR = 1.777; 95% CI: 0.658, 4.803; p = 0.257) and Kaplan–Meier function (log‐rank test: chi‐square (df = 1): 1.32, p = 0.250) analyses did not identify a survival difference between ECMO and non‐ECMO, while multivariate Cox models (HR = 1.821; 95% CI: 0.654, 5.065; p = 0.251) did not demonstrate an increased risk for death. Propensity score matching analysis (HR = 1.500; 95% CI: 0.251, 8.977; p = 0.657) also failed to demonstrate a significantly increased hazard ratio. Using a contemporary cohort of pediatric lung transplant recipients, the use of ECMO at the time of lung transplantation did not negatively impact survival.     

The effect of MMF dose and trough levels on adverse effects in pediatric heart transplant recipients

Limited pharmacokinetic and safety data exist for MMF in pediatric HTR. Previously targeted MPA‐TL are 1.5–3.0 μg/mL. The objective of this study was to assess the outcomes targeting MPA‐TL of 0.8–2.0 μg/mL in pediatric HTR. MPA‐TL were retrospectively collected 2–12 months post‐transplant. Acute rejection, infection, leukopenia, and GI complaints were then correlated with MPA‐TL. A total of 355 MPA‐TL from 22 HTR were included. Median age was 2.5 yr. Primary indication for transplant was dilated cardiomyopathy (64%). Mean MPA‐TL was 1.7 ± 0.9 μg/mL. African American patients received significantly higher doses (702 ± 235 mg/m²) compared with other races (p = 0.035). Leukopenia was less common in patients with SUB MPA vs. others (p = 0.01). MMF was discontinued for GI complaints in one patient and leukopenia in two patients. One SUB patient had acute rejection, and one SUP patient had infection. One‐yr survival was 100%. Targeting a lower range for MPA‐TL was not associated with significant rejection or infection. Despite lower MPA‐TL, MMF was discontinued in 3/22 patients for adverse effects.