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.     

Dense B cell infiltrates in paediatric renal transplant biopsies are predictive of allograft loss

Abstract:  Recent studies have suggested adverse outcome for renal allograft rejection associated with dense CD20 lymphocytic infiltrates in transplant renal biopsies. We investigated further the relationship between renal allograft survival and CD20+ lymphocytic infiltrates in renal transplant biopsies from children with graft dysfunction. Fifty consecutive unselected renal transplant biopsies were performed for investigation of acute, chronic or acute on chronic renal allograft dysfunction in 48 children aged 1–17 (median 13.1) years, at 0–155 (median 22) months post-transplantation with median follow up of 24 months post-biopsy. Seventeen (35%) graft losses occurred at 1–163 (median 49) months post-transplantation. There was increased graft loss in those with dense (>300 cells/hpf) CD20+ lymphocytic infiltrates present on biopsy (p = 0.043). Dense B-cell infiltrates were also associated with increased glucocorticoid requirement in those with acute cellular rejection (p = 0.0015). There were no significant differences in age, sex, HLA-mismatch, type of transplantation, EBV or CMV serology or baseline immunosuppressive regimens between those with or without dense CD20+ infiltrates. Dense CD20+ lymphocytic infiltrates in renal transplant biopsies are associated with adverse clinical outcome, including increased graft loss. This observation raises the possibility of future studies examining the efficacy of B cell depletion therapy in this clinical context.     

Reversible acute anuric kidney injury after surgical evacuation of perinephric hematomas as a complication of renal transplant biopsies

Percutaneous renal transplant biopsy is the gold standard investigation to diagnose the cause of renal allograft dysfunction. There are inherent risks to this investigation, despite the procedure becoming safer due to the increased utilization of ultrasound‐guided techniques. These biopsy risks can be increased when there is acute rejection present with a swollen transplanted kidney. Subcapsular hematomas are not uncommon after percutaneous renal transplant biopsies, but we describe two cases of post‐biopsy subcapsular hematoma which were associated with acute renal allograft dysfunction in pediatric renal transplant recipients who did not have acute rejection.     

A case series of perioperative variables in relation to short‐term outcomes in pediatric renal transplant recipients

Multiple perioperative variables have been shown in existing literature to influence long‐term outcomes of pediatric RTx, such as allograft survival. Their impact on short‐term outcomes is not as well‐documented. This case series aims to investigate the effects of nine perioperative variables on two short‐term outcomes in pRTR: 1‐week post‐operative eGFR and post‐operative LOS. A total of 73 pRTR transplanted over 3 years from 2012 to 2014 at a single center were studied retrospectively and statistical analyses were performed. There was higher 1‐week post‐operative eGFR in pRTR who received living donor transplants compared to those who received deceased donor transplants (P=.01), with mean eGFR of 135 mL/min/1.73 m² and 82 mL/min/1.73 m², respectively. Aorta‐IVC anastomosis was associated with longer LOS compared to iliac vessel anastomosis (P=.03), with median LOS of 19 and 13 days, respectively. There were no significant effects on 1‐week eGFR or LOS of the seven other variables: pRTR age and gender, donor age, preoperative donor SBP, intraoperative mean CVP before graft perfusion, intraoperative median SBP z score after graft perfusion, and intraoperative fluid volume. Living donor transplants were associated with higher 1‐week post‐operative eGFR compared to deceased donor transplants. Aorta‐IVC anastomosis was significantly associated with longer LOS compared to iliac vessel anastomosis.     

BK virus nephropathy in the native kidneys of a pediatric heart transplant recipient

Sahney S, Yorgin P, Zuppan C, Cutler D, Kambham N, Chinnock R. BK virus nephropathy in the native kidneys of a pediatric heart transplant recipient.
Pediatr Transplantation 2010:14:E11–E15. © 2009 Wiley Periodicals, Inc. Abstract: BK virus is a human polyoma virus that may cause nephropathy in immunosuppressed patients. It is a well‐recognized cause of renal allograft dysfunction and allograft loss in renal transplant recipients, but it is an infrequent cause of nephropathy outside this setting. There are a few case reports of BK virus nephropathy in the native kidneys of immunosuppressed adult patients with non‐renal transplants, but so far it has not been reported in pediatric non‐renal solid organ transplant recipients. We report a case of a seven‐yr‐old heart transplant patient who was diagnosed with BK virus nephropathy, eight months after his second heart transplant. Despite intervention, his renal dysfunction progressed to renal failure. He is currently receiving maintenance hemodialysis and awaiting renal transplantation. It is important to recognize BK virus infection as a possible cause of renal dysfunction in immunosuppressed children who are non‐renal transplant recipients.     

Intravenous immunoglobulin therapy in the treatment of BK viremia and nephropathy in pediatric renal transplant recipients

Anyaegbu EI, Almond PS, Milligan T, Allen WR, Gharaybeh S, Al‐Akash SI. Intravenous immunoglobulin therapy in the treatment of BK viremia and nephropathy in pediatric renal transplant recipients.
Pediatr Transplantation 2012: 16: E19–E24. © 2010 John Wiley & Sons A/S. Abstract: Polyoma BKVN is a significant cause of allograft dysfunction and loss in renal transplant recipients. Reduction in immunosuppression is accepted as first‐line therapy to decrease viral load and prevent allograft injury and dysfunction. We report our experience with persistent BKV after reduction in immunosuppression followed by successful clearance of BKV in three pediatric renal transplant recipients and histological resolution of BKVN in a fourth patient following therapy with IVIG. Once BKV was detected, immunosuppression was reduced and BKV was monitored until clearance was achieved. All four patients were given IVIG in a dose of 2 g/kg. Allograft function remained stable in all patients. Early routine screening for BKV allows early intervention to prevent the development of BKVN and permanent allograft damage. While immunosuppression reduction is a logical first‐line therapy, second‐line therapy is not well established. IVIG seems to be an effective treatment for persistent BKV after reduction in immunosuppression and for BKVN and can therefore be considered as a therapeutic option in these patients.     

Routine transplant Doppler ultrasonography following pediatric kidney transplant

The utility and cost-effectiveness of routine transplant renal DU as a screening test in the immediate postoperative period following pediatric renal transplantation has not been systematically evaluated. Our center's transplant protocol includes a routine DU on postoperative day 3, unless an earlier DU was obtained for a specific indication. We retrospectively evaluated 113 consecutive pediatric renal transplant recipients. Indication for DU (routine vs. non-routine), timing, results, and graft outcome data were collected. We determined whether the DU result affected patient management. Eighty routine DU examinations were evaluated. Thirty (37.5%) of the 80 routine DUs had abnormalities. Most abnormalities were minor and did not require intervention. One patient with a dysfunctional bladder had mild hydronephrosis; this led to a decision to increase the frequency of bladder catheterization. This was the only intervention based upon the routine DUs. Twenty percent of routine DUs revealed abnormalities that led to a follow-up study, but none of these studies led to an intervention. The incremental cost of each DU exceeded $1080 and the incremental cost-effectiveness ratio for a documented change in management exceeded $86, 400. Our results suggest that routine post-transplant DU is not cost-effective in pediatric renal allograft recipients.     

The effect of transfer to adult transplant care on kidney function and immunosuppressant drug level variability in pediatric kidney transplant recipients

Adolescent age at time of transplant has been recognized as a risk factor for renal allograft loss. Increased risk for graft failure may persist from adolescence to young adulthood. Transfer of care is hypothesized as a risk factor for non‐adherence and graft loss. We explored whether kidney allograft function declined at an accelerated rate after transfer of care to adult transplant centers and whether coefficient of variation of tacrolimus (CV TAC) trough levels predicted allograft loss. Single‐center, retrospective chart review was performed for pediatric kidney transplant recipients who received transplants between 1999 and 2011. Change in eGFR pre‐ and post‐transfer was performed via a linear mixed‐effects model. CV TAC was calculated in transplant recipients with TAC data pre‐ and post‐transfer. t test was performed to determine the difference between means of CV TAC in subjects with and without allograft loss following transfer of care. Of the 138 subjects who transferred to adult care, 47 subjects with data pre‐ and post‐transfer demonstrated a decrease in the rate of eGFR decline post‐transfer from 8.0 mL/min/1.73 m² per year to 2.1 mL/min/1.73 m² per year, an ~80% decrease in eGFR decline post‐transfer (P = 0.01). Twenty‐four subjects had CV TAC data pre‐ and post‐transfer of care. Pretransfer CV TAC for subjects with allograft loss post‐transfer was significantly higher than in subjects without allograft loss (49% vs 26%, P < 0.05). Transfer of care was not independently associated with acceleration in eGFR decline. CV TAC may aid in identifying patients at risk for allograft loss post‐transfer.     

Masked hypertension and allograft function in pediatric and young adults kidney transplant recipients

Masked hypertension is a common complication of pediatric kidney transplantation. While office hypertension is known to be associated with worse short‐ and long‐term graft function, the role of masked hypertension in allograft dysfunction is not clear. We conducted a retrospective cross‐sectional analysis of 77 consecutive pediatric kidney transplant recipients who had routine 24‐h ambulatory blood pressure monitoring with the aims to estimate the prevalence of masked hypertension and examine its association with allograft function. Masked hypertension was defined as a 24‐h systolic or diastolic blood pressure load ≥25%. Twenty‐nine percent of patients had masked hypertension. Patients with masked hypertension had significantly lower allograft function estimated using the creatinine‐based Schwartz‐Lyon formula, a cystatin C‐based formula, and combined cystatin C and creatinine‐based formulas than patients with normal blood pressure (all p values <0.05). In a multivariable analysis, masked hypertension remained independently associated with worse allograft function after adjustment for age, sex, race, time post‐transplant, rejection history, antihypertensive treatment, and hemoglobin level. We conclude that in young kidney transplant recipients, masked hypertension is common and is associated with worse allograft function. These results support the case for routine ambulatory blood pressure monitoring as the standard of care in these patients to detect and treat masked hypertension.     

How to stent the ureter after kidney transplantation in children?—A comparison of two methods of urinary drainage

Ureteral stenting after pediatric renal transplantation serves to prevent obstruction and urinary leakage, but can also cause complications. This study compares the complication rates of both methods. Data were retrospectively collected at Erasmus MC, Rotterdam, the Netherlands (splint group, n = 61) and Hospital for Sick Children, Toronto, Canada (JJ catheter group, n = 50). Outcome measures included urological interventions and incidence of UTIs during the first 3 months post‐transplantation. The splint was removed after a median of 9 (IQR 8‐12), the JJ catheter after 42 (IQR 36‐50) days. Seven (11.5%) children in the splint group needed at least one urological re‐intervention versus two in the JJ catheter group (P‐value .20). UTIs developed in 19 children (31.1%) in the splint group and in twenty‐five (50.0%) children in the JJ catheter group (P‐value .04), with a total number of 27 vs. 57 UTIs (P‐value .02). Nine (33.3%) vs. 35 (61.4%) of these, respectively, occurred during the presence of the splint (P‐value <.001). Children with a JJ catheter developed more UTIs than children with a splint; the latter, however, tended to require more re‐interventions. Modification of either method is needed to find the best way to stent the ureter.     

A comprehensive strategy in donor acceptance: Impact on pediatric waitlist and heart transplant outcomes

Significant inter‐ and intra‐center practice variability is present in pediatric donor heart acceptability. This may contribute to variation in the donor refusal rate and may impact waitlist time, morbidity, mortality, and transplant rates. In order to reduce practice variability, our center developed and implemented a comprehensive strategy regarding donor acceptance in September 2017. The aim of this study was to assess the impact of this strategy on waitlist time and outcomes as well as early post‐transplant outcomes. We performed a single‐center, retrospective analysis of all pediatric (<18 years) patients listed for single‐organ heart transplant at our center from September 2015 to September 2018. Patients were divided into those listed before (Group 1) and after implementation of the comprehensive strategy (Group 2). The primary end‐point was waitlist time. Secondary end‐points included waitlist removal due to death or clinical deterioration, donor refusals per listed patient, early post‐transplant outcomes (graft failure, mechanical ventilation time, inotropic support, length of hospital stay) and 1‐year post‐transplant survival. Of 78 listed patients, 54 were transplanted (29 in Group 1), 9 were removed due to death or clinical deterioration (7 in Group 1) and 15 were removed due to clinical improvement (12 in Group 1). The waitlist time was significantly shorter in Group 2 (17 days, IQR 7‐53) vs Group 1 (90 days, IQR 14‐162); P = .006. The number of donor refusals was lower in Group 2 (1, IQR 0‐2.2) vs Group 1 (4, IQR 2‐19); P < .001. The percentage of refused donors with normal function (Left ventricular ejection fraction > 50%) was lower in Group 2 vs Group 1 (53% vs 84%; P < .001). Difference in removal from the waitlist for death or deterioration in Group 2 vs Group 1 (n = 2, 7% vs n = 7, 20%, P = .18) did not reach statistical significance. There was no difference in post‐transplant outcomes between groups. The waitlist time and donor refusals significantly decreased after implementation of a comprehensive donor acceptance strategy without impacting transplant outcomes. This analysis supports the need for a comprehensive approach to donor organ acceptance within a pediatric transplant center.     

Impact of a pharmacist‐led vaccine recommendation program for pediatric kidney transplant candidates

Pediatric transplant recipients commonly have deficient vaccination status at the time of transplantation. Utilizing transplant pharmacists to improve vaccination rates has not previously been described. This single‐center, retrospective study evaluated the impact of transplant pharmacist interventions on the completion rate of vaccination schedules at time of kidney transplant. Patients who received pharmacist‐led vaccination recommendations prior to transplant were compared to patients without pharmacist recommendations. Forty‐seven pediatric patients were included: 24 intervention patients and 23 control patients. The median percentage of up‐to‐date vaccinations at time of transplant was significantly higher in intervention group (91%; IQR 86%‐100%) vs. control group (80%; IQR 71%‐80%) (P<.0001). The median change in up‐to‐date vaccinations from time of evaluation to time of transplant was also significantly higher in the intervention group (7.5%) compared to the control group (0%) (P<.0001). There was no difference in live vaccination rates. No patients in either group were readmitted for a vaccine‐preventable disease within 6 months post‐transplant. With pharmacist intervention, significantly more patients were up to date with vaccination schedules at the time of transplant. These results suggest that a transplant pharmacist may serve as a valuable resource to increase vaccination schedule compliance between time of evaluation and transplantation.     

Focal segmental glomerulosclerosis associated with acute cytomegalovirus infection in a renal transplant

Focal segmental glomerulosclerosis (FSGS) occurring in association with cytomegalovirus (CMV) infection in a renal transplant patient with no previous history of FSGS has rarely been reported. We present a case of a 16‐year‐old renal transplant recipient who developed acute hepatitis, leukopenia, nephrotic syndrome, and progressive renal dysfunction in the setting of acute infection with CMV. The cytomegalovirus infection was successfully treated with IV ganciclovir followed by oral valganciclovir but renal function deterioration and massive proteinuria continued. Features of FSGS were found on two renal allograft biopsies. Plasmapheresis and cyclophosphamide treatment was instituted with no clear effect on disease progress.     

Early identification of transplant glomerulopathy in pediatric kidney transplant biopsies: A single‐center experience with electron microscopy analysis

Banff 2013 criteria recommend performing ultrastructural studies with electron microscopy (EM) in kidney transplant biopsies if the technology is available. We sought to determine the impact of EM on enhancing diagnostic findings in pediatric kidney transplant biopsies and the prognostic information gained from the additional findings. All kidney transplant biopsies since routine EM use started on June 1, 2014, until October 31, 2016, were reviewed. Primary outcome measures included the positive yield frequency of EM use defined as an upgraded diagnosis based on EM findings relative to light microscopy, and 12‐month kidney allograft outcome of progression to ESRD or doubling of serum creatinine stratified by transplant glomerulopathy (TG) status on EM. Eighty unique kidney transplant biopsies were reviewed. EM studies were completed for 61 biopsies (76%). Complication rate was low (3.7%). In 61 biopsies where EM was completed, EM findings included foot process fusion (62%), endothelial cell swelling (38%), subendothelial lucencies (31%), and glomerular basement membrane duplication (41%). EM confirmed FSGS recurrence in three cases. In the remaining 58 cases, there was a positive yield of 31% where 18 biopsies were upgraded to a worse category after TG identification on EM. Kidney allograft outcome was poor regardless whether TG was detected early on EM or advanced on LM. Routine EM use in analyzing pediatric kidney transplant biopsies proved safe and provided valuable additional diagnostic information in almost one‐third of cases. Additional studies are needed to determine if clinical interventions for early TG identified on EM can improve long‐term outcomes.     

Liver allograft pathology in healthy pediatric liver transplant recipients

Liver transplantation offers excellent results for children with end‐stage liver disease, and efforts should be directed toward maintaining long‐term graft health. We evaluate graft pathology in healthy pediatric transplant recipients with low‐maintenance immunosuppressive medications to assess whether protocol biopsies are helpful for adapting immunosuppression and protecting long‐term graft function. Liver biopsies were performed on 60 healthy pediatric liver transplant recipients, and histological findings were correlated with laboratory, serological, and radiological results. Fourteen patients (23%) were diagnosed with acute or early chronic rejection, and immunosuppressive medications were increased in these children. Liver function tests did not correlate with histological findings. The incidence of fibrosis was 36% in transplant recipients five or more years after liver transplantation. We observed an unexpectedly high prevalence of rejection and fibrosis in children with no laboratory abnormalities, which led to changes in their immunosuppressive medications. Scheduled biopsies appear to be useful in pediatric transplant recipients with low immunosuppressive medications for early detection of morphological changes in liver transplants. Further studies are needed to evaluate whether adaption of immunosuppression helps to reduce tissue damage and the incidence of allograft dysfunction in the long term.     

Immune cell function assay in pediatric heart transplant recipients

The ImmuKnow^® ICFA reports ex vivo CD4 lymphocyte activation to quantify immunosuppression. Limited organ and age‐specific data exist for pediatric heart transplant recipients. We sought to examine their normative values and ICFA's association with rejection/infection. A total of 380 ICFAs from 58 heart transplant recipients (6.5/recipient) were studied retrospectively. The median age at the time of their first ICFA was 5.3 yr (IQR 2.4–12.1 yr). ICFA levels during immunologic stability (n = 311) were a median of 305 (IQR: 172–483) and mean of 353 (s.d. ± 224) ng ATP/mL. ICFA levels trended lower with advancing age. ICFA levels during immunologic stability increased over time from transplant after the first six months but were not correlated with calcineurin inhibitor levels or the type used. There is no association between ICFA values during stability and rejection (median 368 ATP ng/mL; IQR 153–527) or infection (median 293 ATP ng/mL; IQR 198–432). In contrast to the manufacturer's suggested ranges, the immunologic stable ranges in pediatric cardiac recipients were very different. ICFA values during immunologic stability are related to time from transplant in pediatric heart recipients. ICFA's ability to discriminate rejection or infection from immunologic stability was not demonstrated.     

Bilateral native nephrectomy reduces systemic oxalate level after combined liver‐kidney transplant: A case report

Primary hyperoxaluria type 1 (PH1) is a rare liver enzymatic defect that causes overproduction of plasma oxalate. Accumulation of oxalate in the kidney and subsequent renal failure are fatal to PH1 patients often in pediatric age. Combined liver and kidney transplantation is the therapy of choice for end‐stage renal disease due to PH1. Levels of plasma oxalate remain elevated for several months after liver transplantation, as the residual body oxalate is slowly excreted. Patients with persistent hyperoxaluria after transplant often require hemodialysis, and accumulation of residual oxalate in the kidney can induce graft dysfunction. As the native kidneys are the main target of calcium oxalate accumulation, we postulated that removal of native kidneys could drastically decrease total body oxalate levels after transplantation. Here, we report a case of bilateral nephrectomy at the time of combined liver‐kidney transplantation in a pediatric PH1 patient. Bilateral nephrectomy induced a rapid decrease in plasma oxalate to normal levels in less than 20 days, compared to the several months reported in the literature. Our results suggest that removal of native kidneys could be an effective strategy to decrease the need for hemodialysis and the risk of renal dysfunction after combined liver‐kidney transplantation in patients with PH1.     

Endoscopic antireflux surgery leading to obstruction in pediatric renal transplant patients

To describe a multicenter experience with management of ureteral obstruction after injection of Dx/HA for VUR in pediatric renal transplant patients. The records of all pediatric renal transplant patients who underwent Dx/HA injection for VUR and had subsequent obstruction were identified, and the management and outcomes were reviewed. Follow‐up ranged from 1 to 10 years. There were four patients identified, all of whom had a history of rising creatinine, recurrent UTI, and increasing hydronephrosis which led to the diagnosis of high‐grade VUR. Obstruction was diagnosed within 24‐72 hours after injection in three patients. One patient was asymptomatic, and rising creatinine and hydronephrosis were noted 1 month after injection. One patient was managed expectantly, while three patients underwent ureteral stent placement. After the stent was removed, one patient went on to open reimplant due to delayed obstruction, the second patient with voiding dysfunction is currently managed with an indwelling ureteral stent and may require further definitive surgery, the third patient recovered, and the fourth is being observed. Our cases illustrate that despite initial successful management of the obstruction in some, delayed obstruction is possible and may necessitate open reimplant. It is imperative that these patients have close follow‐up after Dx/HA.     

Evaluation of the current post‐transplantation Human Leukocyte Antigen antibody screening in pediatric renal transplant recipients

The necessity of post‐transplant monitoring for donor‐specific antibodies (DSAs) is unclear. This study evaluates the clinical relevance of post‐transplantation donor‐specific HLA antibodies in pediatric renal transplant recipients, aiming at better stratification of patients at risk of graft dysfunction and better recommendations for post‐transplant monitoring. A cohort of 68 pediatric kidney recipients, involving 76 transplantations between 2004 and 2014, was studied retrospectively. All patients were screened for HLA antibodies at 1, 3, 6, and 12 months after transplantation and yearly thereafter. Samples testing positive were further analyzed to detect DSA. A biopsy was performed on clinical indication. We studied the baseline characteristics of the patients with biopsy, with DSA, and with rejection. We assessed the effect of post‐transplant DSA on clinical outcome, including antibody‐mediated acute rejection and GFR decrease. In our cohort, the prevalence of DSA was 19% (13/68 transplantations). Most patients with HLA antibodies after transplantation were DSA‐positive (76%; 13/17). A clear association between DSA and subsequent rejection was found. At the end of the study period, a significantly lower GFR was found in patients with biopsy, DSA, or rejection. Based on our observations, we recommend routine post‐transplantation screening for HLA and DSA. The presence of DSA justifies a renal biopsy even in the absence of clinical signs of rejection.     

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.