Tacrolimus-based immunosuppression with steroid withdrawal in pediatric kidney transplantation--4-year experience at a moderate-volume center

Tacrolimus-based immunosuppression with steroid withdrawal in pediatric kidney transplantation was pioneered at the University of Pittsburgh but is not broadly practiced at other centers. We present our 4-year experience with a modified Pittsburgh protocol at our own moderate-volume center. Seventeen pediatric kidney transplant recipients were treated with a tacrolimus-based immunosuppressive regimen involving steroid withdrawal over 6-12 post-transplant months in most cases and followed for up to 49 months. Patient and graft survival as well as graft function were excellent, and beneficial effects on several cardiovascular parameters were noted. Complications included fungal infections, glucose intolerance and post-transplant lymphoproliferative disease and were generally managed successfully. While awaiting longer-term follow-up data, we conclude that tacrolimus-based immunosuppression with steroid withdrawal in pediatric kidney transplantation is potentially beneficial and feasible even at centers managing a rather small number of recipients.     

BK viremia and nephropathy in pediatric renal transplant recipients

The renal survival rate of pediatric renal transplant recipients (pRTR) has improved with the use of modern immunosuppressive agents; however, the incidence of post‐transplantation viral infection has increased. This study investigated the incidence of BK viremia and BK viral–associated nephropathy (BKVAN) in pRTR. One‐hundred‐and‐thirty‐four pRTR were divided into two groups: group 1 (n = 20, 14.9%) comprised those who were prospectively followed with longitudinal analyses after renal transplantation in the time period from May 2007 to June 2008, while group 2 (n = 114, 85.1%) cross‐sectional study of those who were transplanted from January 1994 to April 2007. The mean ages at transplantation in groups 1 and 2 were 10.6 ± 4.7 years and 7.8 ± 4.5 years, respectively. BK viremia was detected in four (20.0%) patients in group 1, and seven (6.1%) in group 2 (P = 0.04), with increased incidence associated with induction therapy. The median time to detection of BK viremia after transplantation was 44 days in group 1 and 142 days in group 2. BKVAN was diagnosed in three patients (two in group 1 and one in group 2). All three patients diagnosed with BKVAN were receiving tacrolimus, mycophenolate mofetil, and corticosteroids as maintenance immunosuppression. Reducing immunosuppression resulted in reduced BK viremia. Monitoring for BK viremia and BKVAN is important in pRTR being treated with the current immunosuppressive regimen. The first line of treatment for BK viremia remains careful reduction of immunosuppression and close monitoring of renal allograft function.     

Left ventricular hypertrophy in pediatric kidney transplant recipients: long-term follow-up study

Cross-sectional studies indicate that LVH, known cardiovascular risk factor, is frequent in pediatric patients post-kidney transplant. We performed a retrospective longitudinal analysis of echocardiographic data collected in children and adolescents who received kidney transplant from 1998 to 2003. The first echo was performed at a median time post-transplant of 14 months in 47 children; a second echo (echo 2) was carried out at a median time of 33 months in 31 and a third echo (echo 3) was performed at a median time of 49 months in 14 children. LVH was defined as LV mass index >/=95th percentile for children. LVH was present in echo 1 in 25 (54%) subjects. Systolic blood pressure (p = 0.02) and BMI (p = 0.02) independently predicted the LVH seen in echo1 in multivariate logistic regression. In 14 subjects with three consecutive echocardiograms LVM index significantly decreased from echo 1 to echo 2 and from echo 1 to echo3 (p < 0.05), but no significant changes were observed between echo 2 and echo 3. The overall prevalence of LVH remained unchanged but its severity significantly decreased during the follow-up. The results of the study suggest that despite regression of LVM index overtime-pediatric patients post-kidney transplant are at continuous risk for developing cardiovascular disease.     

Cross-sectional study of BK virus infection in pediatric kidney transplant recipients

BKV reactivation is associated with impaired graft function in adult kidney transplant patients. The clinical impact of BKV infection in the pediatric transplant population has not yet been fully evaluated. The objective of our study was to determine the prevalence of BKV infection in consecutive pediatric kidney transplant recipients in our center. Forty consecutive unselected pediatric kidney transplant recipients were studied. Mean age at screening was 15.6 +/- 5.3 yr and samples were obtained a median of 60.5 months after transplantation (3-123). BKV-DNA was analyzed in urine and plasma by qualitative nested-PCR. A review of the literature was performed. Prevalence of viruria and viremia was 50% and 12.5%, respectively. Viremia was associated with the presence of hematuria (p = 0.02). The mean creatinine level in children without BKV replication was 1.6 mg/dL, BKV viruria was 0.9 mg/dL, and BKV viremia was 0.8 mg/dL. A literature review showed that viruria and viremia were found in 28.2% and 8.5% of cases, respectively; BKV nephropathy was found in 3.8% and graft loss in 11% of the patients with BKV nephropathy and in 0.4% of the children studied. Recipient serostatus was the most important risk factor. The rate of BKV replication and nephropathy among pediatric kidney recipients is similar to that of adults, but the incidence of graft loss is significantly lower.     

Safety and pharmacokinetics of daclizumab in pediatric renal transplant recipients

Abstract:  This study examined the safety and pharmacokinetics/pharmacodynamics of daclizumab in combination with mycophenolate mofetil (or azathioprine), corticosteroids, and cyclosporine or tacrolimus, in 61 pediatric renal allograft recipients in three age groups: less than or equal to five yr (n = 18), 6–12 yr (n = 18), and 13–17 yr (n = 25). The dosing regimen was daclizumab 1.0 mg/kg before transplantation, followed by four biweekly doses. The pharmacokinetics of daclizumab were described using NONMEM software. Median (range) estimated trough daclizumab levels achieved on day 56 (before dose 5) were 3.88 μg/mL (2.48–8.78), 4.54 μg/mL (1.79–18.7), and 4.94 μg/mL (0.05–10.6) in the less than or equal to five yr (n = 15), 6–12 yr (n = 17), and 13–17 yr (n = 22) age groups, respectively. Steady-state median (range) daclizumab exposures were 2040 mg · h/mL (1585–3778), 2757 mg · h/mL (1873–3494) and 3297 mg · h/mL (1705–6453), respectively. Saturation of the IL-2R occurred rapidly and was maintained for greater than or equal to three months after transplantation. Daclizumab was generally well-tolerated with no acute allergic or anaphylactic reactions, deaths or malignancies during the study. The proportion of patients who developed acute rejection at six and 12 months was 8.5% and 16.7%, respectively. This study shows that adding daclizumab at 1 mg/kg to standard immunosuppressive therapy provides safe and effective IL-2R blockade.     

Sirolimus pharmacokinetics in pediatric renal transplant recipients receiving calcineurin inhibitor co-therapy

We have previously reported sirolimus (SRL) pharmacokinetics (PK) in pediatric renal transplant recipients on a calcineurin inhibitor (CNI)-free protocol. We now report pediatric SRL PK in pediatric renal transplant patients receiving SRL + CNI. SRL was dosed to achieve target trough levels between 10 and 20 ng/mL. We performed 49 SRL PK profiles in pediatric renal transplant recipients receiving SRL in combination with either cyclosporine (CsA; 25 profiles), or tacrolimus (TCL; 24 profiles). Ten of the SRL + TCL profiles were obtained from children receiving SRL on a b.i.d. dosing regimen. All other SRL profiles were q.d. regimens. We calculated, the maximum concentration (C(max)), AUC, apparent clearance (aCL; dose/AUC) for dose in mg/m(2), and mean residence time (MRT). SRL levels were measured at 6 and 7 time points for b.i.d. and q.d. dosing, respectively. Regression analysis of SRL trough values vs. AUC showed good correlation in the SRL q.d. + CsA, SRL q.d. + TCL, and SRL b.i.d. + TCL groups (r(2) = 0.95, 0.68, and 0.44, respectively). SRL aCL corrected for body surface area was higher in children aged 0-5 yr receiving SRL with either CsA or TCL. SRL dosing schedule should be tailored to each patient. Higher SRL aCL may be present in younger children when administered with CNI.     

Long‐term outcomes of pediatric kidney transplant recipients with a pretransplant malignancy

A childhood malignancy can rarely progress to ESRD requiring a KT. To date, few reports describe long‐term outcomes of pediatric KT recipients with a pretransplant malignancy. Between 1963 and 2015, 884 pediatric (age: 0‐17 years old) recipients received 1055 KTs at our institution. KT outcomes were analyzed in children with a pretransplant malignancy. We identified 14 patients who had a pretransplant malignancy prior to KT; the majority were <10 years old at the time of KT. Ten (71%) patients received their grafts from living donors, the majority of which were related to the recipient. Wilms' tumor was the dominant type of pretransplant malignancy, seen in 50% of patients. The other pretransplant malignancy types were EBV‐positive lymphoproliferative disorders, non‐EBV‐positive lymphoma, leukemia, neuroblastoma, soft‐tissue sarcoma, and ovarian cancer. Ten of the 14 patients received chemotherapy as part of their pretransplant malignancy treatment. Graft survival at 1, 3, and 5 years was 93%, 83%, and 72%, respectively. Patient survival at 1, 5, and 10 years was 100%, 91%, and 83%, respectively. Six (40%) patients suffered AR following KT; half of them had their first episode of AR within 1 month of KT. Our single‐center experience demonstrates that pediatric KT recipients with a previously treated pretransplant malignancy did not exhibit worse outcomes than other pediatric KT patients.     

Early steroid withdrawal in pediatric renal transplant on newer immunosuppressive drugs

Steroids have been a cornerstone in renal transplant immunosuppression. New immunosuppressive drugs have led to protocols using early steroid withdrawal or complete avoidance. A prospective protocol in 23 pediatric renal transplant (ages 2-14 yr) who received decreasing steroid doses stopping at day 7 post-Tx, FK, and MMF were compared with a CsA, AZT, historically matched steroid-based control group. Basiliximab was used in two doses. Anthropometric, biochemical variables, AR rates, and CMV infection were evaluated and compared using Student's t-test and regression analysis. A better growth pattern was seen in steroid withdrawal group. GFR rate and serum glucose were similar in both groups. Total serum cholesterol levels were significantly lower in steroid withdrawal group. The incidence of AR at 12 months was 4.3% in steroid withdrawal group vs. 8.6% in steroid-based group (p = ns). No difference in CMV infection was observed. Hemoglobin levels were low during the first months in both groups; reached normal values after six months. SBP became higher at 12 months in steroid-based group. Patient and graft survival was 98% in both groups at one-yr post-transplant. Early steroid withdrawal was efficacious, safe, and did not increase risk of rejection, preserving optimal growth, renal function, and reducing cardiovascular risk factors.     

Efficacy and tolerability of interleukin-2 receptor blockade with basiliximab in pediatric renal transplant recipients

Rejection remains a major threat in pediatric renal transplantation (Tx), causing graft failure and increased exposure to drugs. The new chimeric antibody, basiliximab, directed against the alpha-chain of the interleukin-2 receptor (IL-2R), has been shown to be effective in preventing rejection episodes in adult renal transplant recipients. In our single-center experience from Essen, Germany, we evaluated prospectively the efficacy and tolerability of basiliximab, in combination with cyclosporin A (CsA) and prednisone, in 38 unselected pediatric patients. Mean patient age at Tx was 10.1 yr. Twenty-eight children received a cadaveric organ and 10 children received living-related donor grafts. The 1-yr patient survival rate was 100% and the 1-yr graft survival rate was 95% (36/38 patients). No graft was lost as a result of immunological factors, and single rejection episodes were observed in eight patients (21%). Two of these rejections were steroid-resistant and responded to tacrolimus rescue therapy. The rate of infections was not enhanced; overt cytomegalovirus (CMV) disease was observed in two patients only. Malignancies have not been seen to date. The blockade of the alpha-chain of the IL-2R lasted for up to 6 weeks. We conclude that the addition of basiliximab to standard immunosuppression in pediatric renal transplant recipients is well tolerated and results in a low incidence of rejection. The simple mode of application and the lack of side-effects make basiliximab an especially useful adjunct in pediatric patients.     

Efficacy and pharmacokinetics of tacrolimus oral suspension in pediatric liver transplant recipients

The use of tacrolimus in small pediatric graft recipients may require the availability of a suspension formulation for appropriate dose titration and easier administration. The pharmacokinetics (Pk) of an extemporaneously prepared oral suspension of tacrolimus (OST) was investigated in 15 pediatric liver transplant recipients, and was compared with the corresponding data with tacrolimus capsules (TC). Graft and patient survival rates were 100%. Acute rejection and steroid-resistant rejection were encountered in 9/15 and 3/15 patients, respectively. Comparison of Pk data showed a lower oral absorption of OST when compared with TC. No significant correlation could be made between the Pk parameters and rejection. Despite the lower bioavailability of OST when compared with TC, the rejection incidence was similar with both formulations (60% vs. 55%, respectively). Accordingly, the use of OST may constitute an alternative option for tacrolimus administration in low body weight organ recipients, to allow dosage titration in the early post-transplant weeks.     

Post‐transplant glucose status in 61 pediatric renal transplant recipients: Preliminary results of five Turkish pediatric nephrology centers

Buyan N, Bilge I, Turkmen MA, Bayrakci U, Emre S, Fidan K, Baskin E, Gok F, Bas F, Bideci A. Post‐transplant glucose status in 61 pediatric renal transplant recipients: Preliminary results of five Turkish pediatric nephrology centers.
Pediatr Transplantation 2010:14:203–211 © 2009 John Wiley & Sons A/S. Abstract: To assess the incidence, risk factors and outcomes of PTDM, a total of 61 non‐diabetic children (24 girls, 37 boys, age: 14.5 ± 2.1 yr) were examined after their first kidney transplantation (37.3 ± 21.6 months) with an OGTT. At baseline, 16 (26.2%) patients had IGT, 45 (73.8%) had NGT, and no patient had PTDM. No significant difference was shown between TAC‐ and CSA‐treated patients in terms of IGT. Higher BMI z‐scores (p = 0.011), LDL‐cholesterol (p < 0.05) and triglyceride levels (p < 0.01), HOMA‐IR (p = 0.013) and lower HOMA‐%β (p = 0.011) were significantly associated with IGT. Fifty‐four patients were re‐evaluated after six months; eight patients with baseline IGT (50%) improved to NGT, three (19%) developed PTDM requiring insulin therapy, five (31%) remained with IGT, and four patients progressed from NGT to either IGT (two) or PTDM (two). These 12 progressive patients had significantly higher total cholesterol (p < 0.05), triglycerides (p < 0.05), HOMA‐IR (p < 0.01) and lower HOMA‐%β (p < 0.0) than non‐progressive patients at baseline. We can conclude that post‐transplantation glucose abnormalities are common in Turkish pediatric kidney recipients, and higher BMI z‐scores and triglyceride concentrations are the main risk factors. Considering that the progressive patients are significantly more insulin resistant at baseline, we suggest that the utility of both HOMA‐IR and HOMA‐%β in predicting future risk of PTDM and/or IGT should be evaluated in children.     

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.     

Graft loss due to recurrent disease in pediatric kidney transplant recipients on a rapid prednisone discontinuation protocol

Chavers BM, Rheault MN, Gillingham KJ, Matas AJ. Graft loss due to recurrent disease in pediatric kidney transplant recipients on a rapid prednisone discontinuation protocol. Abstract: Recurrent disease is the fourth most common cause of graft loss (GL) in pediatric KTx recipients. We studied the incidence of recurrent disease and GL due to recurrent disease in pediatric KTx recipients on a RDP protocol. Between 2002 and 2010, we performed 74 KTxs in patients aged 5–18 yr using an RDP protocol, 25 (34%) were at risk of recurrence of primary disease. Outcomes were compared to 69 historical controls (18 [26%] at risk of recurrence), KTx between 1996 and 2000. Follow‐up period was 39 ± 25 months in RDP and 124 ± 38 months in controls. The incidence of recurrent disease at three yr post‐KTx was 16% in RDP and 28% in controls (p = NS). Mean time to recurrent disease was 22 ± 26 months in RDP and 46 ± 48 months in controls (p = 0.54). Nine (12%) grafts were lost in the RDP group (1‐recurrence) and 32 (46%) in the control group (4‐recurrence). Time to GL was 85 months in the RDP recipient and 46 ± 21 months in controls. An RDP protocol in pediatric KTx recipients may not be associated with increased risk of graft loss due to recurrent disease.     

Lymphocyte‐depleting induction therapy lowers the risk of acute rejection in African American pediatric kidney transplant recipients

The use of lymphocyte‐depleting induction immunosuppression has been associated with a reduction in risk of AR after KT among adult recipients, particularly among high‐risk subgroups such as AAs. However, data on induction regimen and AR risk are lacking among pediatric KT recipients. We examined outcomes among 7884 first‐time pediatric KT recipients using SRTR data (2000‐2014). Characteristics were compared across race using Wilcoxon rank‐sum tests for continuous and chi‐square tests for categorical variables. Risk of AR was estimated using modified Poisson regression, stratified by recipient race, adjusting for recipient age, gender, BMI, primary diagnosis, number of HLA mismatches, maintenance immunosuppression, and donor type. Risk of AR within 1 year was lower in AA recipients receiving lymphocyte‐depleting induction (ATG or alemtuzumab; RR, 0.66; 95% CI, 0.52‐0.83 P < .001) compared to AA recipients receiving anti‐IL‐2 receptor antibody induction. This difference was not seen in non‐AA recipients receiving lymphocyte‐depleting induction (RR, 0.93; 95% CI, 0.81‐1.06, P = .26) compared to IL‐2 induction. These findings support a role for lymphocyte‐depleting induction agents in AA pediatric patients undergoing KT and continued use of IL‐2 inhibitor induction in non‐AA pediatric KT recipients.     

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.     

Long-term results of basiliximab induction immunosuppression in pediatric liver transplant recipients

It has been shown that an induction therapy with the monoclonal anti-interleukin-2 receptor antibody basiliximab (Simulect) is capable to reduce the incidence of acute graft rejection in adult and pediatric liver transplantation (Ltx). However, data on long-term results using basiliximab in children post-Ltx are still pending. Therefore, the objective of our study was to report on the long-term results of basiliximab induction therapy in pediatric liver transplant recipients. A total of 54 children received two single doses of basiliximab in addition to cyclosporine and prednisolone following Ltx. We analyzed the incidence of acute and chronic graft rejection that of post-transplant lymphoproliferative disease (PTLD), and patient and graft survival. The follow-up was 22-46 months. The historical control group (matched controls) consisted of 54 patients treated with a cyclosporine and prednisolone dual therapy. Patient survival was 53 of 54 in the treatment group and 51 of 54 in the controls. One patient was retransplanted in the treatment group vs. three patients in the control group. The incidence of acute graft rejection was 16.6% compared with 53.7% in the control group (p < 0.001), that of chronic rejection was comparable in both groups (one of 54 vs. one of 54). The incidence of steroid resistant rejection was four of 54 vs. six of 54 that of PTLD were one of 54 vs. zero of 54. There were no adverse effects observed, which could be related to the antibody treatment. We conclude that basiliximab provides safe and effective induction immunosuppression in pediatric liver graft recipients. Short- and even long-term results are excellent.     

Determinants of graft survival in pediatric and adolescent live donor kidney transplant recipients: a single center experience

To study the independent determinants of graft survival among pediatric and adolescent live donor kidney transplant recipients. Between March 1976 and March 2004, 1600 live donor kidney transplants were carried out in our center. Of them 284 were 20 yr old or younger (mean age 13.1 yr, ranging from 5 to 20 yr). Evaluation of the possible variables that may affect graft survival were carried out using univariate and multivariate analyses. Studied factors included age, gender, relation between donor and recipient, original kidney disease, ABO blood group, pretransplant blood transfusion, human leukocyte antigen (HLA) matching, pretransplant dialysis, height standard deviation score (SDS), pretransplant hypertension, cold ischemia time, number of renal arteries, ureteral anastomosis, time to diuresis, time of transplantation, occurrence of acute tubular necrosis (ATN), primary and secondary immunosuppression, total dose of steroids in the first 3 months, development of acute rejection and post-transplant hypertension. Using univariate analysis, the significant predictors for graft survival were HLA matching, type of primary urinary recontinuity, time to diuresis, ATN, acute rejection and post-transplant hypertension. The multivariate analysis restricted the significance to acute rejection and post-transplant hypertension. The independent determinants of graft survival in live-donor pediatric and adolescent renal transplant recipients are acute rejection and post-transplant hypertension.