Pediatric Renal Transplant Patients Research Articles

Examining Health‐Related Quality of Life (HRQoL), disease‐specific quality of life, and coping behaviors in adolescents with renal disease

AbstractIntroductionTo examine and compare the Health‐Related Quality of Life (HRQoL) and disease‐specific HRQoL of pediatric renal dialysis and transplant patients based on patients' perspectives. The coping strategies employed by these two groups of patients were also investigated.MethodsTen adolescents who had undergone kidney transplants (mean age 17.80 ± 1.55 years) and 19 adolescents who were receiving dialysis treatments (mean age 17.16 ± 2.19 years) participated in the study and were asked to complete three questionnaires: PedsQL 4.0 Generic Core Module, PedsQL End‐Stage Renal Disease Module, and the KIDCOPE.ResultsCompared to pediatric kidney transplant patients, adolescents on dialysis reported more difficulties with school functioning and lower overall HRQoL. They also reported having more concerns with adhering to treatment and diets, more problems with family and peer interaction, and lower disease‐specific HRQoL than transplant patients. Differences in preferred types of coping strategies were found based on gender and type of medical treatment.DiscussionDirections for future research to further investigate the variables associated with psychological wellbeing and adaptive coping among pediatric renal patients were discussed based on study findings. Possible psychosocial variables that might have influenced detected differences in patients' HRQoL outcomes between the transplant and dialysis groups were also discussed, with a focus on the types of coping strategies employed by the respective patient groups.

Are fibroblast growth factor 23 concentrations in renal transplant patients different from non-transplanted chronic kidney disease patients?

To compare the pattern of serum FGF23 levels in pediatric renal transplant recipients and GFR-matched controls. We performed a cross-sectional matched pair study in 19 stable pediatric renal transplant recipients and 19 GFR-matched controls with native CKD. After assessment for normal distribution, demographic and bone metabolism parameters were compared with Student's t-test, Wilcoxon's matched pairs (for non-normal distribution) test, and correlation analysis. The groups were comparable for anthropometric parameters, cystatin C eGFR (71.10 ± 37.28 vs. 76.11 ± 26.80 mL/min/1.73 m(2) ), cystatin C, urea, creatinine, intact PTH, pH, CRP, alkaline phosphatase, phosphate, calcium, ionized calcium, FGF-23 (63.44 [IQR 38.42, 76.29], 49.92 [IQR 42.48, 76.97]), albumin, and urinary calcium/creatinine ratio. The renal transplant patients had significantly lower 25-(OH) vitamin D levels (66.63 ± 17.54 vs. 91.42 ± 29.16 ng/mL), and higher 1,25-(OH)(2) vitamin D levels (95.78 ± 34.54 vs. 67.11 ± 35.90 pm). FGF-23 levels correlated negatively with cystatin C eGFR (r = -0.3571, p = 0.02770) and positively with PTH (r = 0.5063, p = 0.0026), but not with serum phosphate (r = 0.2651, p = 0.1077). We conclude that the increase in FGF23 levels with GFR decline in pediatric renal transplant patients remains similar to that in the patients with CKD. The relationship between FGF23 and serum vitamin D needs further evaluation.

Understanding renal posttransplantation anemia in the pediatric population.

Advances in renal transplantation management have proven to be beneficial in improving graft and patient survival. One of the properties of a well-functioning renal allograft is the secretion of adequate amounts of the hormone erythropoietin to stimulate erythropoiesis. Posttransplantation anemia (PTA) may occur at any point in time following transplantation, and the cause is multifactoral. Much of our understanding of PTA is based on studies of adult transplant recipients. The limited number of studies that have been reported on pediatric renal transplant patients appear to indicate that PTA is prevalent in this patient population. Erythropoietin deficiency or resistance is commonly associated with iron deficiency. An understanding of the risk factors, pathophysiology and management of PTA in the pediatric renal transplant population may provide guidelines for clinicians and researchers in the pursuit of larger prospective randomized control studies aimed at improving our limited knowledge of PTA. Recognition of PTA through regular screening and evaluation of the multiple factors that may contribute to its development are recommended after transplantation.

Clinical Description and Evolution of Renal Transplant Pediatric Patients Treated with Alemtuzumab

Background Renal transplantation is the most effective treatment for children with end-stage renal disease. Recent work suggests that induction with alemtuzumab in the pediatric population permits the use of lower doses of maintenance immunosuppressive therapy. In addition, it has a low cost compared with other induction therapies. Objective To conduct a clinical description of pediatric renal transplant patients comparing induction protocols to evaluate graft and patient survival, infections complications, and lymphoproliferative diseases. Materials and Methods This descriptive and retrospective study, of evaluated pediatric renal transplant patients between 2006 and 2010. Results The agents for induction therapy were: alemtuzumab (61.5%), daclizumab (19.25%), and thymoglobulin (19.25%). Graft survival was better among the alemtuzumab group (87.5%) compared with the other two induction therapies (80%). The frequency of acute rejection episodes during the first year posttransplantation as well as chronic rejection was lower among the alemtuzumab group. Cytomegalovirus infection was noted in 30% of patients with greater frequency among those induced with alemtuzumab. Conclusion Induction therapy with alemtuzumab was safe in a pediatric population not predisposing to a greater risk of acute or chronic rejection. Except for a greater incidence of Cytomegalovirus, there was no difference in other complications.

Intraindividual variability of the modified Schwartz and novel CKiD GFR equations in pediatric renal transplant patients

GFR in children can be obtained from a formula using SCr and height or various formulas including serum CysC. Recently, two new GFR formulas have been developed: (i) height and SCr-mSchwartz GFR and (ii) height, SCr, CysC, and serum urea (CKiD GFR). While these formulas proved to be accurate when compared to the gold standard, their use in children post-kidney Tx is yet to be assessed. A total of 1174 blood samples (urea, SCr and CysC) were analyzed from the post-Tx period in 24 Tx children (12 boys, median age = 8.6 yr) currently followed at our institution. CKiD GFR and mSchwartz GFR were compared using Bland-Altman analysis and the CV. The mSchwartz GFR overestimated the CKiD GFR (mean bias = 1.09 ± 0.14; 95% limits of agreements from 0.82 to 1.36). Median CV of CKiD GFR (10.3%) was significantly lower than that of mSchwartz GFR (15.0%), p = 0.04, and negatively correlated with the slope of GFR (r(2) = 0.34, p = 0.0026). In conclusion, CKiD GFR has a significantly lower intraindividual variation than mSchwartz GFR and may be better suited for longitudinal follow-up of patients post-Tx.

Epstein-Barr Virus Gene Expression, Human Leukocyte Antigen Alleles and Chronic High Viral Loads in Pediatric Renal Transplant Patients

Studies have identified solid organ transplant recipients who remain asymptomatic despite maintaining chronic high Epstein-Barr virus (EBV) viral loads. We examined clinical manifestations, EBV gene expression, human leukocyte antigen (HLA) alleles, and specific T-cell responses to EBV infection in pediatric renal transplant patients. Seventeen pediatric renal transplant patients were categorized according to EBV viral load into those with chronic high viral loads (CHL) and recipients who resolve EBV infection (REI). EBV gene expression was analyzed using real-time PCR assays and EBV-specific T cells were analyzed by flow cytometry. EBV gene, EBV-encoded small RNA 1, was expressed at significantly higher levels in CHL compared with EBV seropositive controls (P=0.005) and raised compared with REI. BamHI A right-ward transcripts were also expressed at higher levels in CHL patients (P=0.03) than in REI. Expression of latent genes, EBNA1, LMP1, LMP2, and lytic gene BZLF1 were restricted to the CHL group with viral gene expression varying over time. HLA-A*02 allele expression was predominant in CHL patients (80%) and GLC lytic-specific cytotoxic T-lymphocytes were absent. In contrast, HLA-B*08 allele expression was prevalent in REI patients (71%) and RAK lytic cytotoxic T-lymphocytes were detected in all patients. EBV gene expression in CHL carriers differs from those that resolve infection and should be interpreted alongside HLA polymorphisms.

Graft Failure and Adaptation Period to Adult Healthcare Centers in Pediatric Renal Transplant Patients

Transfer from pediatric to adult care may require a period of adaptation to the new healthcare environment. We sought to determine whether this adaptation period was associated with an increased risk of graft failure. Children (age, 0-18 years) recorded in the Canadian Organ Replacement Register who received a first kidney transplant in a pediatric health center between 1992 and 2007, and who had more than or equal to 3 months of graft function, were followed up until death, loss to follow-up, or December 31, 2007. Cox proportional hazards models were used to estimate the excess risk associated with a period of adaptation to adult-oriented care, defined as the interval 0.5 years before to 2.5 years after the first recorded adult care visit. Models were adjusted for age, gender, donor source, and ethnicity. Of the 413 patients evaluated, 149 were transferred to adult care during study period. In total, 78 (18.9%) patients experienced graft failure-23 during the adaptation period. Compared with the period before adaptation, the adjusted hazard ratio for graft loss within the adaptation period was 2.24 (95% confidence interval [CI]: 1.19-4.20). The adjusted graft failure rate was 2.26 (1.04-4.93) times higher after 18 years of age than between 0 and 13 years. Aboriginal ethnicity and deceased donor source were also associated with a significantly higher risk of graft failure. The period of adaptation to adult-oriented care is associated with a high risk of graft failure in pediatric renal transplant patients.

A severely immunocompromised child with uncomplicated oseltamivir‐resistant 2009 H1N1 pandemic influenza infection

2009 H1N1 pandemic influenza was associated with increased risk for severe disease in children and the immunosuppressed. We report a case of uncomplicated pneumonia because of infection with oseltamivir-resistant 2009 H1N1 virus in an immunosuppressed pediatric renal transplant patient. Innate immunity and/or altered viral fitness may be responsible for the mild clinical phenotype of the case.

24 Weeks of Valganciclovir Prophylaxis in Children After Renal Transplantation: A 4-Year Experience

Cytomegalovirus (CMV) is the most common opportunistic infection after solid-organ transplant. Valganciclovir prophylaxis significantly reduces disease, but limited data are available on its use in children. Recently, an increase in delayed-onset CMV disease has been noted with some arguing that longer prophylaxis may decrease late-onset disease. Single-center, retrospective analysis of pediatric renal transplant patients receiving 24 weeks valganciclovir prophylaxis (15 mg/kg/day, maximum 900 mg/day) from January 2004 to December 2008, aiming to measure the incidence of CMV disease and toxicity of valganciclovir. We enrolled 111 patients, 60% males, 46% African Americans, and median age at transplant 14.5 years (range 1.4-20.4 years). Sixty-nine percent of donors and 44% of recipients were seropositive pretransplant. Median duration of valganciclovir use was 5.9 months (range 0.5-24 months). CMV viremia and disease occurred in 27% and 4.5%, respectively. All patients with disease presented after prophylaxis ended and all were D+/R-. Thymoglobulin use (P = 0.04) and positive donor CMV status (P = 0.02) were associated with a higher risk of CMV viremia. Twenty-four percent had hematologic toxicity directly associated with valganciclovir. Valganciclovir use in children was effective as prophylaxis against CMV disease; no children at our institution developed disease while on therapy. Our regimen of 24 weeks of prophylaxis was associated with a lower rate of late-onset disease than previous reports with 12-week regimens. Further controlled studies should be considered to compare longer versus shorter periods of prophylaxis and dose reductions and their impact on prevention of late-onset disease, resistance, cost, and toxicity.

Progressive multifocal leukoencephalopathy (PML) after transplantation

Progressive multifocal leukoencephalopathy (PML) after transplantation

Challenges in pediatric transplantation: The impact of chronic kidney disease and cardiovascular risk factors on long‐term outcomes and recommended management strategies

Barriers to successful outcomes following pediatric transplantation have shifted from ischemic reperfusion injury and rejection to more long-term complications. Of particular concern is the high prevalence of CKD owing to preexisting damage and nephrotoxicity, as well as other CV complications such as hypertension and cardiomyopathy. All of these contribute to graft loss and shortened life expectancy, thereby limiting the success story of solid-organ transplantation. Managing CKD and related CV morbidity should be integral to the care of pediatric transplant patients, and timely detection of any irregularities would increase the chances of restoring lost kidney function. GFR is still the widely accepted indicator of renal function, and nuclear medicine techniques are the gold standard measurement methods. These methods are limited by costs, radiation exposure and substrate injection, and current practice still uses the Schwartz estimate, despite its well-documented limitations. Newer endogenous markers of GFR, such as cystatin C clearance, give a more accurate measure of true GFR but have not been embraced in the management of pediatric transplant recipients. Furthermore, indirect markers (e.g., microalbuminuria and hypertension) could also aid early detection of renal damage. The effects of mainstay immunosuppressants on kidney and heart function are varied, with available data indicating favorable outcomes with tacrolimus compared with ciclosporin. There is a need for appropriately designed and powered randomized controlled trials to validate innovative concepts for tailored immunosuppression in the pediatric population. To date, very few studies have generated long-term data in pediatric renal transplant patients - results of 1-4-yr study favored tacrolimus over ciclosporin, but other immunosuppressive agents also need to be evaluated.

The modified Barry technique to prevent vesicoureteric reflux in paediatric renal transplant recipients: Initial recipient outcomes

ObjectiveWe present the initial clinical results of the ‘modified Barry technique’ for the prevention of VUR in paediatric renal transplant grafts. Ours is the only centre in the UK using this technique, as confirmed in a questionnaire developed in our department. Patients and methodsWe retrospectively analysed data of 15 paediatric renal transplant patients (operated June 2006–November 2009) who had their vesicoureteric anastomosis performed using the modified Barry technique with a 2-cm submucosal anti-reflux tunnel. The original Barry technique involved the creation of a 4-cm tunnel; this was modified by us to reduce the risk of ureteric stenosis. ResultsAt a median follow up of 23.7 months (6.3–39.4), the incidence of VUR was 7% (1/15). There was no evidence of postoperative urological complications, such as urinary leak, primary ureteric obstruction including anastomotic stricture/stenosis, transplant graft renal calculi and chronic rejection. At current follow up, graft and patient survival are 100%. ConclusionWith the introduction of the modified Barry technique, the incidence of VUR in our series fell 10-fold to 7%, compared with our earlier study (P<0.0001), without any urological complications. Although the initial results are encouraging, larger patient numbers and longer follow up are required to validate this technique further.

Population Pharmacokinetics and Pharmacogenetics of Mycophenolic Acid Following Administration of Mycophenolate Mofetil in De Novo Pediatric Renal‐Transplant Patients

The objective was to develop a population pharmacokinetic-pharmacogenetic model of mycophenolic acid following administration of mycophenolate mofetil (MMF) in de novo pediatric renal-transplant patients and identify factors that explain variability. The pharmacokinetic samples were collected from 89 de novo pediatric renal-transplant patients treated with MMF and studied during the first 60 postoperative days. All patients were genotyped for UGT1A8-A9, UGT2B7, and ABCC2. Population pharmacokinetic analysis was performed with the NONMEM and was validated using bootstrap visual predictive check. The pharmacokinetic data were best described by a 2-compartment model with Erlang distribution to describe the absorption phase. The covariate analysis identified body weight as an individual factor influencing central volume of distribution and concomitant immunosuppressive medication and identified body weight and UGT2B7 802C>T genotype as individual factors influencing apparent oral clearance (CL/F) of MMF. CL/F in cyclosporine-MMF-treated patients was 33% higher than in tacrolimus-MMF-treated patients. The CL/F was significantly lower in patients with UGT2B7 802 C/C genotype compared with patients with UGT2B7 802 C/T and 802T/T genotypes, and this effect was independent of concomitant immunosuppressive medication or body weight. The population pharmacokinetic-pharmacogenetic model of mycophenolic acid was validated. Body weight, concomitant medication, and UGT2B7 genotype contribute significantly to the interindividual variability of MMF disposition in pediatric renal-transplant patients.

Hodgkin Lymphoma Post-Transplant Lymphoproliferative Disorder Following Pediatric Renal Transplant

Post-transplant lymphoproliferative disorder (PTLD) occurs in 1.2% of pediatric renal transplant patients, and is frequently Epstein-Barr Virus mediated. Hodgkin Lymphoma PTLD is the rarest of the 4 types of PTLDs recognized by the World Health Organization, with an incidence of <4% of all PTLD patients. It has a distinct clinical course and treatment from all other types of PTLD. This is a case of a 16-year-old girl who had a renal transplant in 2000 due to Moya Moya disease. Her first F-18 FDG PET/CT done in 2006 showed mildly FDG-avid mediastinal adenopathy (histologically nonspecific reactive nodes), however in 2009, after presenting with fevers, a repeat PET/CT showed extensive intensely FDG-avid disease. Biopsy of a supraclavicular node identified Hodgkin Lymphoma PTLD. The patient was treated with chemotherapy and reimaged, showing excellent response to therapy. In contrast, classic PTLD is treated by withdrawal of immunosuppression and administration of Rituximab. F-18 FDG PET/CT is known to be very useful in the staging and monitoring of response to therapy in the setting of classic PTLD. In this case, serial F-18 FDG PET/CT scans proved very useful in the evaluation and follow-up of the rare and distinct Hodgkin Lymphoma PTLD subtype.

Transient hyperphosphatasemia in pediatric renal transplant patients - Is there a need for concern and when?

TH of infancy and early childhood is characterized by transiently increased S-ALP, predominantly its bone or liver isoforms. There are neither signs of metabolic bone disease or hepatopathy corresponding to the increased S-ALP, nor a common underlying/triggering disease. TH may also occur in children post-renal Tx, which may raise significant concerns and anxiety. We describe four patients aged 2.8-7 yr in whom the TH occurred at 11-34 (median = 28) months after Tx and lasted from 40 to 105 (median = 63) days. No obvious cause/trigger of TH could be found; the clinical status and bone turnover were not altered. In cases of TH post-Tx, we recommend the evaluation of basic biochemical indices and wrist X-ray. If these results are normal, TH is most likely the diagnosis and the S-ALP can be monitored over the next three months without further testing. In patients with persisting TH for more than three months and/or in children with pre-existing or suspected metabolic bone disease, further evaluation may be indicated. In conclusion, TH is a benign disorder in patients post-Tx. Detailed investigation including bone biopsy is only indicated in patients with persisting TH.

The Role of Immunosuppression in Malignancies Among 351 Pediatric Renal Transplant Patients

The incidence of de novo malignancies over a 38 year experience in 351 children ranging in age from 2 to 18 years was investigated among subjects prescribed various immunosuppressive protocols. There were 14 children (3.98%) who showed de novo malignancies, namely, 4.86 cancers for every 1000 graft-function years (GFYs). Among patients who had grafts functioning for >10 years, 7.4% suffered from cancer. Nine patients survive without a recurrence at a mean of 12.5 ± 6.6 years including 6 with graft function. Among group I who were treated with pre–calcineurin inhibitor (CNI) therapy 3 (3.8%) children (1 male and 2 females) developed a malignancy at a mean of 15.2 ± 11.9 years posttransplant (range, 7–35), for 4.65 cancers every 1000 GFYs. Two of them survive with functioning grafts. Among group II, who were treated by CNIs there were 273 children including 24 retransplants. Group II showed 11 malignancies (4.0%), for 5.04 malignancies for every 1000 GFYs. The incidence of cancer was similar in the 2 groups, undergoing different immunosuppressive regimens; however, the malignancies in the CNI- group were more precocious, compared with those of the conventionally-treated cohort.

Imaging chronic renal disease and renal transplant in children

At Great Ormond Street Hospital we have the highest number of paediatric renal transplant patients in Europe, taking cases from across the United Kingdom and abroad. Our caseload includes many children with rare complicating medical problems and chronic renal failure related morbidity. This review aims to provide an overview of our experience of imaging children with chronic renal failure and transplants.

Bone marrow aplasia and graft loss in a pediatric renal transplant patient with polyomavirus nephropathy

Sirs, BK-virus nephropathy (BKN) is an important cause of graft dysfunction in kidney transplant recipients. Severe allograft dysfunction and graft loss are well-known complications [1–3]. However, pancytopenia caused by an infection of the bone marrow is thus far an unknown complication of BK virus (BKV) infection. We report a 17-year-old boy with end-stage renal disease due to peripartal asphyxia who was transplanted with a cadaveric kidney. Posttransplantation immunosuppressive therapy (IS) consisted of tacrolimus, mycophenolate mofetil (MMF), prednisolone, and basiliximab (Simulect ®) as induction therapy. Eighteen months after transplantation, IS was diminished because of detection of BK viruria and viremia. As this could not improve the number of BKV copies and serum creatinine increased, cidofovir (Vistide ® 1 mg/kg) was administered IV weekly (four times). A graft biopsy 4 months later showed a BKN Drachenberg B1 [3] without signs of acute humoral or cellular rejection. MMF was discontinued, and tacrolimus was diminished until trough levels of 4–5 μg/l were achieved. Despite these interventions, our patient was hospitalized 2 months later because of high and recurrent fever, pancytopenia, and deterioration of renal function. BKV polymerase chain reaction (PCR) in plasma at that time was strongly elevated: >5,000,000 copies/ml (7.7 log copies/ml), and hemoglobin, white blood cell, and thrombocyte count were unacceptably low. Adjunctive therapy was started: six extra doses of cidofovir and five of immunoglobulin (Multigam ® 2 g/kg) were administrated IV over a period of 4 weeks. A bone marrow biopsy showed global aplasia, and PCR was positive for BKV (>5,000,000 copies/ml). All other causes of pancytopenia, such as Epstein-Barr virus (EBV), cytomegalovirus (CMV), Parvovirus B19, human herpes virus-6 (HHV-6), malignancy, or hemophagocytic syndrome were excluded; tacrolimus and prednisolone were discontinued, and treatment with granulocyte colony stimulating factor (GCS) and erythropoietin was started. As the boy’s condition was life threatening due to persistent pancytopenia, deterioration of renal function, and systemic aspergillosis, and as severe BKN with BKV infection of the bone marrow seemed to be the cause of this, it was decided to remove the graft 2.5 months after the initial biopsy. The nephrectomy specimen showed BKN Drachenberg grade B3 [3], without signs of acute rejection. After removal of the graft, the patient’s general condition improved quickly: fever disappeared, and plasma BKV PCR copies decreased rapidly. BKV was no longer detectable in plasma after 11 days and in urine 3 months after transplantectomy. The bone marrow recovered very slowly over several months. Figure 1 shows the evolution of hemoglobin (Hb), white blood cell count (WBC), creatinine, and polyomavirus (BK) copy numbers after discovery of BK shedding in urine. S. H. M. Gardeniers :D. Mekahli : E. Levtchenko : R. Van Damme-Lombaerts Department of Pediatric Nephrology, UZ Leuven, Leuven, Belgium

Active human Cytomegalovirus infection and Glycoprotein B genotypes in Brazilian pediatric renal or hematopoietic stem cell transplantation patients

A prospective analysis of active Human Cytomegalovirus infection (HCMV) was conducted on 33 pediatric renal or hematopoietic stem cell post-transplant patients. The HCMV-DNA positive samples were evaluated for the prevalence of different gB subtypes and their subsequent correlation with clinical signs. The surveillance of HCMV active infection was based on the monitoring of antigenemia (AGM) and on a nested polymerase chain reaction (N-PCR) for the detection of HCMV in the patients studied. Using restriction analysis of the gB gene sequence by PCR-RFLP (Restriction Fragment Length Polymorphism), different HCMV strains could be detected and classified in at least four HCMV genotypes. Thirty-three pediatric recipients of renal or bone marrow transplantation were monitored. Twenty out of thirty-three (60.6%) patients demonstrated active HCMV infection. gB1 and gB2 genotypes were more frequent in this population. In this study, we observed that gB2 had correlation with reactivation of HCMV infection and that patients with mixture of genotypes did not show any symptoms of HCMV disease. Future studies has been made to confirm this.

Pharmacokinetics and pharmacodynamics of basiliximab in Japanese pediatric renal transplant patients

This study was aimed at evaluating the pharmacokinetics and pharmacodynamics of basiliximab in Japanese pediatric renal transplant patients. This study was carried out with the approval of the Institutional Review Board of our institution. Written consent was obtained from the legal representative of each patient, as also from the patients themselves where possible. Eligible patients were Japanese pediatric patients weighing less than 35 kg and younger than 15 years of age who were scheduled to undergo renal transplantation. Each patient was given intravenous basiliximab at the total dose of 20 mg administered in two divided doses of 10 mg each on the day of transplantation and on the fourth day after transplantation. Cyclosporine and corticosteroids were also administered as the basic concomitant maintenance immunosuppressive therapy. The time course of changes in the serum basiliximab concentrations and the percentage of CD25+ T-lymphocytes in the peripheral blood were determined up to 26 weeks after the transplantation to calculate the period of suppression of the CD25+ T-lymphocytes. Serum basiliximab was measured by an ELISA technique, and the percentage of CD25+ T-lymphocytes in the peripheral blood was determined by flow cytometry. 6 Japanese pediatric patients weighing less than 35 kg and aged over 1 year and less than 15 years who were scheduled to undergo renal transplantation were enrolled in this study. In regard to the time course of changes of the serum basiliximab concentration, after the peak serum concentration was reached, basiliximab was gradually eliminated from the blood with a mean half-life of 7.06 days. CD25+ T-lymphocytes in the peripheral blood were suppressed completely when the serum concentration of basiliximab was over 0.2 microg/ml, and the period of suppression of the CD25+ T cells was 40.3 - 51.7 days (mean +/- SD; 45.8 +/- 4.9). Changes in the serum concentration of basiliximab and the period of suppression of CD25+ peripheral blood T-lymphocytes in Japanese pediatric renal transplant patients were similar to those reported for non-Japanese pediatric transplant patients and Japanese adult renal transplant patients with a cyclosporine and corticosteroid regimen. This indicates that expected efficacy can be obtained in Japanese pediatric renal transplant patients using the recommended dosing regimens validated by non-Japanese studies.