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.     

Eight‐year follow‐up in pediatric living donor kidney recipients receiving alemtuzumab induction

Recipient lymphocytes are crucial for direct and indirect pathways of allorecognition. We proposed that the administration of alemtuzumab several weeks pretransplantation could eradicate peripheral lymphatic cells and promote donor‐specific acceptance. This was a single‐center, retrospective review of 101 consecutive living donor kidney transplantations in pediatric patients (age 7 months—18 years), performed between September 2006 and April 2010. IS protocol included two 30 mg doses of alemtuzumab: The first was given 12‐29 days prior to transplantation, and the second at the time of transplantation. Maintenance IS was based on combination of low‐dose CNI and mycophenolate, with steroids tapered over the first 5 days post‐transplantation. Patients were followed for 7.8±1.3 years, and protocol biopsies were taken 1 month, 1, 3, and 5 years post‐transplant. The Kaplan‐Meier 8‐year patient and graft survival rates in the cyclosporine‐treated patients were 82.0±7.3% and 71.6±7.3, and in the tacrolimus‐treated patients were 97.2±5.4 and 83.8±6.0%. Biopsy‐proven acute rejection developed in 35% of cyclosporine‐treated patients and in 8% of tacrolimus‐treated patients. Alemtuzumab pretreatment prior to LRD kidney transplantation, followed by maintenance immunosuppression with tacrolimus and MMF, is associated with reasonable long‐term results in pediatric patients.     

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.     

Sirolimus as renal and immunological rescue agent in pediatric liver transplant recipients

CNI have improved the outcome of LT. However, their inherent potential to nephrotoxic and sometimes-inadequate immunosuppressive effect has lead to the usage of newer drugs like SRL. Aim of this study was to review children who received SRL. Thirty-seven (20 women) children post-LT, median age 10.4 yr (0.8-17.4) with a minimum follow-up of six months comprised the study group. Indications for SRL were biopsy-proven resistant acute allograft rejection (n = 12), early CR (n = 12), and CNI-induced nephropathy with MMF intolerance (n = 11). In two patients, the indication was the recurrence of BSEP disease in the allograft. In patients with acute rejection, AST normalized in 10/12 patients. In patients with CR, AST normalized in 6/12 patients. Those with renal impairment showed improvement in their creatinine levels from a mean baseline of 99-56.7 μm (p = 0.03) and their mean cystatin C was 1.02 after SRL. Side effects leading to discontinuation of SRL were seen in three patients. SRL was effective in rescuing patients with acute and chronic allograft rejection and improving renal function in CNI-induced nephropathy group.     

Post‐renal transplant erythrocytosis: A case report

PTE is defined as hematocrit >51% or hemoglobin >17 g/dL after renal transplantation. Risk factors include native kidneys with adequate erythropoiesis pretransplant, smoking, renal artery stenosis, and cyclosporine treatment. We report the case of a 14‐yr‐old female kidney transplant patient, with triple therapy immunosuppression and stable graft function who developed PTE at 12 months post‐transplant with hemoglobin 17.3 g/dL, hematocrit 54.2%, stable graft function, and normotensive with normal cardiac echocardiogram and erythropoietin levels. The only risk factor found was tobacco use. As she had no spontaneous improvement, enalapril treatment was started at 19 months post‐transplant with a hemoglobin level of 17.5 g/dL and hematocrit 53%; by 23 months post‐transplant, hemoglobin lowered to 15 g/dL and hematocrit to 44.5% and continued to be in normal range thereafter. PTE is a rare condition in childhood and can be successfully treated with enalapril.     

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.     

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.     

Subclinical cardiovascular changes in pediatric solid organ transplant recipients: A systematic review and meta‐analysis

CV disease is a major cause of morbidity and mortality following solid organ transplantation in adults. While the prevalence of multiple cardiometabolic risk factors is increased in pediatric solid organ transplant recipients, it is not clear whether they have subclinical CV changes. cIMT, central pWV, and CAC are indicative of subclinical CV disease, and, in adults, predict future CV events. The objective of this systematic review and meta‐analysis was to investigate the prevalence of subclinical CV changes, as measured by cIMT, pWV, and CAC among pediatric solid organ transplant recipients. We searched MEDLINE^® and EMBASE and conducted meta‐analysis for studies that evaluated cIMT, central pWV, and CAC among pediatric solid organ transplant recipients (kidney, lung, intestine and liver). The search identified nine eligible studies that included a total of 259 patients and 685 healthy controls. Eight studies reported on kidney transplant recipients and one study on a combined cohort of kidney and liver transplant recipients. The mean cIMT of transplant recipients was significantly higher than that of healthy controls (mean difference = 0.05 mm, 95% CI 0.02–0.07; p < 0.0001) with an estimated pooled prevalence of elevated cIMT of 56.0% (95% CI 17.0–95.0). The one study that assessed pWV showed increased vascular stiffness in transplant recipients compared to healthy controls. No studies assessing for CAC were found. There were limited data regarding subclinical CV disease following pediatric solid organ transplantation. In conclusion, kidney transplantation in childhood is associated with a higher prevalence of subclinical CV changes compared to healthy children. Longitudinal studies are needed to determine whether children have increased CV morbidity and mortality after transplantation.     

Long-term evaluation of cyclosporine and tacrolimus based immunosuppression in pediatric liver transplantation

Both calcineurin inhibitors (CNIs), cyclosporine and tacrolimus, are widely used in pediatric liver transplant recipients and currently data are limited with regards to long-term results using the one drug or the other in comparable low doses. We conducted the present study to assess the advantages and disadvantages of both drugs in children at least five yr post-liver transplantation. A total of 129 children were enrolled in the study. Thirty-eight of the children were switched to tacrolimus monotherapy for different reasons [steroid resistant graft rejection (n = 15), chronic rejection (n = 5), severe acute rejection (n = 4), repetitive acute graft rejection (n = 5), dysfunction of the transplant (n = 3), insufficient CsA metabolism (n = 3), hypertrichosis (n = 2), and CsA toxicity (n = 1)], four patients had primary tacrolimus therapy, and 87 patients are receiving cyclosporine. Mean trough levels were 5.3 +/- 2.3 ng/mL (tacrolimus) and 73.6 +/- 44.5 micro/L (cyclosporine), respectively at least five yr post-orthotopic liver transplantation (OLT). There was no significant difference in the calculated glomerular filtration rate between children on cyclosporine and tacrolimus (142.7 + 39.5 mL/min/1.73 m(2) vs. 151.1 +/- 44.1 mL/min/1.73 m(2)). The incidence of arterial hypertension was 7.1% vs. 9.2%, that of hepatotoxicity was 0% vs. 2.3%. Cosmetic changes were found in more than one-third of the patients on cyclosporine and in 4.8% of the patients receiving tacrolimus. Quality of life was excellent in both groups (self assessment). The impact of CNIs on chronic graft dysfunction cannot be assessed by our present study. We conclude from the results that cyclosporine and tacrolimus are both excellent drugs for maintenance immunosuppression in the long-term course following pediatric liver transplantation. However, this retrospective analysis is limited by the bias between children on CsA as compared with patients receiving tacrolimus. A prospective randomized controlled trial is needed in order to assess which CNI is the best for children following OLT.     

Post‐transplant lymphoproliferative disorder in pediatric intestinal transplant recipients: A literature review

Intestinal transplantation is a successful treatment for children with intestinal failure, but has many potential complications. PTLD, a clinically and histologically diverse malignancy, occurs frequently after intestinal transplantation and can be fatal. The management of this disease is particularly challenging. The rejection‐prone intestinal allograft requires high levels of immunosuppression, a precondition for PTLD. While EBV infection clearly plays a role in disease pathogenesis, the relatively naïve immune system of children is another likely contributor. As a result, pediatric intestine recipients have a higher risk of developing PTLD than other solid organ recipients. Other risk factors for disease development such as molecular and genomic changes that precipitate malignant transformation are not fully understood, especially among children. Studies on adults have started to describe the molecular pathogenesis of PTLD, but the genomic landscape of the malignancy remains largely undefined in pediatric intestinal transplant patients. In this review, we describe what is known about PTLD in pediatric patients after intestinal transplant and highlight current knowledge gaps to better direct future investigations in the pediatric population.     

Post‐transplant malignancies in pediatric organ transplant recipients

The majority of cancer diagnoses in pediatric solid organ transplant recipients (SOTRs) are post‐transplantation lymphoproliferative disorders (PTLD) or skin cancers. However, pediatric SOTRs are also at significantly elevated risk for multiple other solid and hematological cancers. The risks of specific cancers vary by transplanted organ, underlying disease, and immunosuppression factors. More than one‐quarter of pediatric SOTRs develop cancer within 30 years of transplantation and their risk of solid cancer is 14 times greater than the general population. Pediatric SOTRs are at significantly higher risk of cancer‐associated death. Improving patient survival among pediatric SOTRs puts them at risk of adult epithelial cancers associated with environmental carcinogenic exposures. Vaccination against oncogenic viruses and avoidance of excessive immunosuppression may reduce the risk of solid cancers following transplantation. Patient and family education regarding photoprotection is an essential component of skin cancer prevention. There is significant variability in cancer screening recommendations for SOTRs and general population approaches are typically not validated for transplant populations. An individualized approach to cancer screening should be developed based on estimated cancer risk, patient life expectancy, and screening test performance.     

Prednisone withdrawal in pediatric kidney transplant recipients on tacrolimus-based immunosuppression: four-year data

Corticosteroids have been used in renal transplant immunosuppression for over 40 yr. Despite their adverse effects, steroid therapy continues to be part of early as well as maintenance immunosuppression in most pediatric renal transplant centers. The association of steroids with growth retardation, weight gain, and acne may be particularly distressing during the critical years of adolescence and young adulthood, increasing the risk of medication non-adherence. This study reviews the outcomes of pediatric renal transplant patients treated with low-dose tacrolimus, mycophenolate mofetil, or azathioprine, and planned prednisone withdrawal. Thirty-seven pediatric renal transplant recipients were withdrawn from steroids. The mean follow-up after steroid withdrawal was 42+/-19 months. Graft and patient survival were 100%. The mean serum creatinine levels and calculated creatinine clearances remained stable throughout the period of observation. The mean creatinine clearance was 96+/-24 mL/min/1.73 m2 at steroid withdrawal and 93+/-20 mL/min/1.73 m2 at the latest follow-up. Five patients restarted prednisone; in four (11%) it was for suspected or confirmed acute rejection. Improvements were observed in serum lipid profiles, blood pressure, and body mass index. Most patients experienced catchup or stable growth after prednisone withdrawal. Four patients developed viral infections; all were successfully treated. The potential benefits of steroid withdrawal in pediatric renal transplantation are supported by our results.     

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.     

Use of belatacept to maintain adequate early immunosuppression in calcineurin‐mediated microangiopathic hemolysis post‐renal transplant

We report a 17‐yr‐old boy who developed a microangiopathic hemolytic anemia presumed secondary to tacrolimus shortly following a living‐related donor renal transplant. This was initially managed by plasmapheresis. Reinstitution of calcineurin inhibition using cyclosporine led to recurrence of hemolysis, so an alternative agent was needed. He was commenced on monthly intravenous belatacept, with no further recurrence of the hemolysis, and subsequent stable graft function. Modulation via CTLA‐4 offers an alternative immunosuppressive tactic if current regimens produce graft threatening adverse effects. The method of administration and frequency of dosage of belatacept also lends itself well to the high‐risk period of adolescence and transition. We propose that belatacept may therefore also have utility in difficult cases complicated by poor concordance, common in the adolescent age group.     

Evaluation of the vaccination status in pediatric renal transplant recipients

Abstract:  To assess the immunization status of pediatric renal transplant patients followed at a single center in Brazil, vaccination charts of all patients aged between one and 18 yr were analyzed both pre- and post-transplantation. Appropriate immunization was defined according to the National Immunization Program (routine vaccines) – for all Brazilian children – and the Special Immunobiological Agents Program that also includes special vaccines for immunodeficient or other high-risk children. A total of 46 patients was evaluated (mean age 13.7 yr; range 4–17 yr). Vaccination charts were found to be up to date in only two patients (4.3%) pretransplant and in two (4.3%) post-transplant. Although 37 patients (80.4%) in the pretransplant phase and 24 (52.1%) in the post-transplant phase had been vaccinated according to the National Immunization Program, they had not received the special vaccines indicated for their immunocompromised condition. Therefore, despite being followed at a referral center, almost all patients presented an incomplete immunization status pre- and post-transplant. This probably reflects missed opportunities and medical/parental apprehension related to vaccination of patients with chronic renal insufficiency, dialysis or kidney transplantation. Efforts should be made to ensure adequate vaccination in children with kidney diseases, especially before kidney transplantation.     

Prevalence of renal dysfunction in tacrolimus‐treated pediatric transplant recipients: A systematic review

Renal dysfunction after non‐renal transplantation in adult tacrolimus‐treated transplant patients is well documented. Little is known about its prevalence in children. Age‐related changes in both disposition and effect of tacrolimus as well as renal function may preclude extrapolation of adult data to children. To systematically review the literature on renal dysfunction in non‐renal pediatric transplant recipients treated with tacrolimus. PubMed/Medline, Embase, and Google were searched from their inception until April 19, 2012, with the search terms “tacrolimus,” “renal function,” “transplantation,” and “children.” Eighteen of 385 retrieved papers were considered relevant. Twelve dealt with liver, four with heart transplant, one with heart and lung transplant, and one with intestinal recipients. Reported prevalences of mild and severe chronic kidney disease ranged from 0% to 39% and 0% to 71.4%, respectively, for liver, and from 22.7% to 40% and 6.8% to 46%, respectively, for heart and/or lung transplant recipients. Ranges remained wide after adjusting for follow‐up time and disease severity. Possible explanations are inclusion bias and definitions used for renal dysfunction. A considerable proportion of pediatric non‐renal transplant patients who receive tacrolimus‐based immunosuppression, appear to suffer from chronic kidney disease. This conclusion warrants further research into the real risk, its risk factors, and individualization of immunosuppressant therapy.     

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.     

Hyperhomocysteinemia in pediatric and young adult renal transplant recipients

Hyperhomocysteinemia (HHcy) has been recently identified as an important and reversible cardiovascular risk factor in adult and pediatric renal transplant recipients. A retrospective cross-sectional analysis of 70 pediatric and young adult renal transplant recipients was performed to determine the prevalence, and important clinical and laboratory correlates of HHcy. Total homocysteine concentration, free and protein bound, was determined by fluorescence polarization immunoassay using an IMX analyzer. Hyperhomocysteinemia was defined as a serum homocysteine (Hcy) level above the 95th percentile for age. Fifty-four of 70 patients (77%) had HHcy. Comparison of patients with HHcy with patients without HHcy demonstrated no statistical difference in age (p = 0.35), gender (p = 0.76) or donor type (p = 0.20). Patients with HHcy had significantly lower calculated creatinine clearance values (Ccr) (p = 0.02), 67.3 +/- 21.2 mL/min/1.73 m(2) vs. 90.7 +/- 32.3 mL/min/1.73 m(2) for patients without HHcy. Immunosuppression did not correlate with the diagnosis of HHcy. Stepwise logistic regression identified patient age (0.18, p = 0.013) and Ccr (-0.04, p = 0.011) as significant variables. In conclusion, HHcy is more common than expected in pediatric renal transplant recipients. Patients with Ccr <80 mL/min/1.73 m(2) were statistically more likely to have a diagnosis of HHcy. We recommend that Hcy levels should be evaluated in this high risk population.