Dynamic prediction models for graft failure in paediatric kidney transplantation.

BACKGROUND: Several models have been proposed to predict kidney graft failure in adult recipients but none in younger recipients. Our objective was to propose a dynamic prediction model for graft failure in young kidney transplant recipients. METHODS: We included 793 kidney transplant recipients waitlisted before the age of 18 years who received a first kidney transplantation before the age of 21 years in France in 2002-13 and survived >90 days with a functioning graft. We used a Cox model including baseline predictors only (sex, age at transplant, primary kidney disease, dialysis duration, donor type and age, human leucocyte antigen matching, cytomegalovirus serostatus, cold ischaemia time and delayed graft function) and two joint models also accounting for post-transplant estimated glomerular filtration rate (eGFR) trajectory. Predictive performances were evaluated using a cross-validated area under the curve (AUC) and R2 curves. RESULTS: When predicting the risk of graft failure from any time within the first 7 years after paediatric kidney transplantation, the predictions for the following 3 or 5 years were accurate and much better with the joint models than with the Cox model (AUC ranged from 0.83 to 0.91 for the joint models versus 0.56 to 0.64 for the Cox model). CONCLUSION: Accounting for post-transplant eGFR trajectory strongly increased the accuracy of graft failure prediction in young kidney transplant recipients.

Dilatation of the aorta in children with advanced chronic kidney disease.

BACKGROUND: The peculiarity of the cardiovascular risk profile with increased arterial vulnerability is well known in adults with chronic kidney disease (CKD). It is explained by an increased incidence of traditional cardiovascular risk factors together with other comorbidities related to the uremic condition and cardiorenal syndrome (CRS). The present study aimed to determine the cardiovascular impact of the uremic condition in a pediatric population with advanced CKD. METHODS: From 2016 to 2018, 39 consecutive patients with advanced CKD who underwent echocardiographic evaluation were included. All echocardiographic examinations were performed by the same operator (FE). Demographic, clinical, biological, and echocardiographic data were collected. RESULTS: The mean age at echocardiographic exam was 9.7 ± 4.6 years. Twenty-four (61.5%) patients were on hemodialysis; 17 (43.6%) patients were in a peritoneal dialysis program of whom 11 switched at a later stage to hemodialysis. Eight (20.5%) patients had an arteriovenous fistula (AVF). Hypertension was present in 30 (76.9%) patients while left ventricular hypertrophy (LVH) was described in 13 (33.3%) patients. Dilatation of the ascending aorta (Z-score > 2) was found in 15 (38.4%) patients and was statistically (in univariate analysis) related to gender, hypertension, the presence of an AVF, and the use of hemodialysis after peritoneal dialysis (p = 0.024, p = 0.016, p = 0.006, p = 0.009, respectively). CONCLUSION: In addition to classical and predictable abnormalities related to CKD, we found a high prevalence of dilatation of the ascending aorta in children with advanced CKD. Hypertension, AVF, and hemodialysis were associated factors.

Technical feasibility and correlations between shear-wave elastography and histology in kidney fibrosis in children.

BACKGROUND: Ultrasound elastography has been suggested for assessing organ fibrosis. OBJECTIVE: To study the feasibility of shear-wave elastography in children with kidney disease and the correlation between elasticity and kidney fibrosis in order to reduce the indications for kidney biopsy and its complications. MATERIALS AND METHODS: Four operators measured kidney elasticity in children with kidney diseases or transplants, all of whom also had a renal biopsy. We assessed the feasibility and the intraobserver variability of the elasticity measurements for each probe used and each kidney explored. Then we tested the correlation between elasticity measurements and the presence of fibrosis. RESULTS: Overall, we analyzed 95 children and adolescents, 31 of whom had renal transplant. Measurements with the convex probe were possible in 100% of cases. Linear probe analysis was only possible for 20% of native kidneys and 50% of transplants. Intraobserver variabilities ranged from moderate to high, depending on the probe and kidney studied. Elasticity was higher with the linear probe than with the convex probe (P<0.001 for left kidney and P=0.03 for right kidney). Measurements did not differ from one kidney to another in the same child. Elasticity and fibrosis were both higher in transplant patients (P=0.02 with convex probe; P=0.01 with linear probe; P=0.04 overall). There was no correlation between elasticity and fibrosis. CONCLUSION: Of the devices used in this work, kidney elastography was more accurately analyzed with a convex probe. Our study did not identify any correlation between elasticity and kidney fibrosis.

Social deprivation is associated with poor kidney transplantation outcome in children.

Socioeconomic status is an important determinant of health. Its impact on kidney transplantation outcome has been studied among adults but data in children are scarce, especially in Europe. Here, we investigate the association between the level of social deprivation (determined by the continuous score European Deprivation Index) and graft failure risk in pediatric kidney transplant recipients. All patients listed under 18 years of age who received a first kidney transplant between 2002 and 2014 in France were included. Of 1050 kidney transplant recipients (males 59%, median age at transplantation 13.2 years, preemptive transplantation 23%), 211 graft failures occurred within a median followup of 5.9 years. Thirty-seven percent of these patients belong to the most deprived quintile, suggesting that deprivation is more frequent in pediatric patients with end-stage kidney disease (ESKD) than in the general population. Five- and ten-year graft survival were 85% and 69%, respectively, in the most deprived quintile vs. 90% and 83%, respectively, in the least deprived quintile. At any time after transplantation, patients in the most deprived quintile had almost a two-fold higher hazard of graft failure compared with the least deprived quintile, after adjustment for age at renal replacement therapy, duration of dialysis, primary kidney disease, and rural/urban living environment (hazard ratio 1.99; 95% confidence interval 1.20-3.28). The hazard of graft failure did not differ significantly between girls and boys. Thus, our findings suggest a lower socioeconomic status is independently associated with poor graft outcome in pediatric kidney transplantation.

Human papillomavirus type 7-associated anal condyloma after renal transplantation in a child.

The prevalence, clinical significance, and spectrum of many HPV genotypes are currently largely untapped. We report a case of anal condyloma associated with a rare HPV genotype in a 11-year-old kidney transplant recipient. Eleven months post-graft, rectal bleeding revealed a 5-cm-large anal condyloma for which immuno-histopathology revealed typical papillomatosis. HPV genotyping performed on anal biopsy identified a HPV type 7, for which a single sequence was found in the GenBank sequence database. HPV7 is classically found in hand cutaneous warts, but HPV7-associated condyloma was only described in two patients. Total resection of the anal lesion was performed by electrocoagulation with no recurrence after 6 years. Post-transplant immunosuppression may promote anal condyloma with uncommon HPV types. HPV genotyping in such lesions is useful to get a better understanding of the epidemiology and clinical significance of such unusual HPV types as HPV7.

Renal transplantation in children under 3 years of age: Experience from a single-center study.

RTx remains challenging in children under 3 years of age. This single-center study reviewed the medical records of children <3 years transplanted since 1987 (N = 32, Group 1). They were matched for donor type and RTx period with children aged 3-13 years (N = 32, Group 2) and 13-18 years (N = 32, Group 3). There were no between-group significant differences regarding distributions of gender, primary renal disease, proportion of dialysis before RTx, and growth (SDS). Compared to Groups 2 and 3, Group 1 had more peritoneal dialyses (P < .001), more EBV mismatches (P = .04), and longer warm ischemia times (P < .001). The risk of graft loss was not significantly different among age groups (hazard ratio, 2.4 in Group 2 and 2.0 in Group 3 vs Group 1; P = .2). Death occurred in four patients (3 in Group 1 and 1 in Group 2) and graft loss occurred in 28 patients, mainly due to chronic allograft nephropathy. In recipients <3 years of age, the outcomes of RTx are close to those obtained in older pediatric age groups. Thus, young patients may be transplanted in experienced multidisciplinary teams without additional risks provided that particular attention is paid to donor selection and prevention/early diagnosis of comorbidities and complications.

Pharmacogenetics of post-transplant diabetes mellitus in children with renal transplantation treated with tacrolimus.

BACKGROUND: Post-transplant diabetes mellitus (PTDM) is a major complication of immunosuppressive therapy, with many risk factors reported in adults with renal transplantation. The objective of this study was to investigate potential non-genetic and genetic risk factors of PTDM in children with renal transplantation treated with tacrolimus. METHODS: A national database was screened for patients developing PTDM within 4 years following tacrolimus introduction. PTDM was defined as glucose disorder requiring anti-diabetic treatment. PTDM patients were matched to "non-PTDM" control transplanted children according to age, gender, and duration of post-transplant follow-up. Patients were genotyped for six selected genetic variants in POR*28 (rs1057868), PPARa (rs4253728), CYP3A5 (rs776746), VDR (rs2228570 and rs731236), and ABCB1 (rs1045642) genes, implicated in glucose homeostasis and tacrolimus disposition. RESULTS: Among the 98 children with renal transplantation enrolled in this multicentre study, 18 developed PTDM. None of the clinical and biological parameters was significant between PTDM and control patients. Homozygous carriers of POR*28 or wild-type ABCB1 (rs1045642) gene variants were more frequent in PTDM than in control patients with differences close to significance (p = 0.114 and p = 0.066 respectively). A genetic score based on these variants demonstrated that POR*28/*28 and ABCB1 CC or CT genotype carriers were at a significantly higher risk of developing PTDM after renal transplantation. CONCLUSION: Identification of PTDM risk factors should allow clinicians to allocate the best immunosuppressant for each patient with renal transplantation, and improve care for patients who are at a higher risk.

Rapid access to renal transplant waiting list in children: impact of patient and centre characteristics in France.

BACKGROUND: Major inequalities in access to renal transplant waiting lists have been demonstrated among adult patients both in the USA and Europe. In this French nationwide study, we sought to ascertain the influence of patient and centre characteristics. METHODS: We included all children (<18 years) in the French End-Stage Renal Disease National Registry, who started renal replacement therapy (RRT) between 1 January 2002 and 31 December 2011. The primary outcome was the probability of being listed within 6 months after starting RRT. Hierarchical logistic regression models were used to study the association between the patient or the centre characteristics and the outcome. Centre effects were assessed by studying the centre-level residual variance. RESULTS: A total of 614 incident patients treated in 54 centres were included; 421 (68.6%) were listed within 6 months after starting RRT. A higher risk of not being listed was found in patients younger than 2 years or with a renal disease with a high risk of recurrence after transplantation [odds ratio (OR): 2.61; 95% confidence interval (CI): 1.37-4.97]. We found a significant vintage effect: the probability of not being listed decreased over time (OR per 1 year +0.83, 95% CI: 0.74-0.94). Although we found no significant gender effect, a trend towards disfavouring girls persisted over the study period. We found a significant centre effect that remained after adjusting for patient characteristics. However, none of the centre characteristics that we studied (centre size, pre-emptive transplantation program, paediatric versus adult centres and the proportion of patients on the waiting list placed on inactive status during the first month after listing) explained this variability. CONCLUSIONS: Our study confirms inequalities among children in rapid access to the renal transplant waiting list and shows that patient and centre characteristics play a role in these inequalities. Further studies focusing on the organization and practices of the centres are needed to explain the remaining variability.

Rituximab fails where eculizumab restores renal function in C3nef-related DDD.

BACKGROUND: Dense deposit disease (DDD), a C3 glomerulopathy (C3G), is a rare disease with unfavorable progression towards end-stage kidney disease. The pathogenesis of DDD is due to cytotoxic effects related to acquired or genetic dysregulation of the complement alternative pathway, which is at times accompanied by the production of C3 nephritic factor (C3NeF), an auto-antibody directed against the alternative C3 convertase. Available treatments include plasma exchange, CD20-targeted antibodies, and a terminal complement blockade via the anti-C5 monoclonal antibody eculizumab. CASE-DIAGNOSIS/TREATMENT: We report here the case of an 8-year-old child with C3NeF and refractory DDD who presented with a nephritic syndrome. She tested positive for C3NeF activity; C3 was undetectable. Genetic analyses of the alternative complement pathway were normal. Methylprednisolone pulses and mycophenolate mofetil treatment resulted in complete recovery of renal function and a reduction in proteinuria. Corticosteroids were tapered and then withdrawn. Four months after corticosteroid discontinuation, hematuria and proteinuria recurred, and a renal biopsy confirmed an active DDD with a majority of extracapillary crescents. Despite an increase in immunosuppressive drugs, including methylprednisolone pulses and rituximab therapy, the patient suffered acute renal failure within 3 weeks, requiring dialysis. Eculizumab treatment resulted in a quick and impressive response. Hematuria very quickly resolved, kidney function improved, and no further dialysis was required. The patient received bimonthly eculizumab injections of 600 mg, allowing for normalization of renal function and reduction of proteinuria to <0.5 g per day. Since then, she continues to receive eculizumab. CONCLUSION: Complement regulation pathway-targeted therapy may be a specific and useful treatment for rapidly progressing DDD prior to the development of glomerulosclerosis. Our data provide evidence supporting the pivotal role of complement alternative pathway abnormalities in C3G with DDD.

National survey of prevention and management of CMV infection in pediatric kidney transplantation in comparison to clinical practice guidelines.

Background: Cytomegalovirus (CMV) is one of the most frequent opportunistic infections in kidney transplant (KT) recipients and is a risk factor for patient and graft survival after KT. Center-to-center variation, optimal prevention and treatment strategies in pediatric KT are currently unknown. This survey aimed to assess current CMV prevention and treatment strategies used among French pediatric KT centers. Methods: A web-based survey was sent to all 13 French pediatric kidney transplantation centers. Results: Twelve (92%) centers responded to the survey. All centers used prophylaxis for the donor-positive/recipient-negative (D+/R-) group. For R + patients, 54% used prophylaxis, 37% used a pre-emptive strategy. In the low-risk group, D-/R-, 50% used a pre-emptive approach and 50% had no specific prevention strategy. The antiviral used by all centers for prophylaxis was valganciclovir (VGCV). The duration of prophylaxis varied from 3 to 7 months and the duration of viral load monitoring varied from 6 months to indefinitely. No center used a hybrid/sequential approach. For the treatment of CMV DNAemia, VGCV or intravenous GCV were used. Therapeutic drug monitoring of VGCV was performed in 5 centers (42%). Five centers reported drug resistance. Eight centers (67%) administered VGCV during the treatment of acute graft rejection. Conclusions: There is uniformity in CMV management in some areas among pediatric KT centers in France but not in others which remain diverse and are not up to date with current guidelines, suggesting unnecessary variation which could be reduced with better evidence to inform practice.

Preemptive Kidney Transplantation Is Associated With Transplantation Outcomes in Children: Results From the French Kidney Replacement Therapy Registry.

BACKGROUND: Kidney transplantation (KT) is the optimal treatment for children with end-stage kidney disease. The aim of this study was to evaluate the impact of preemptive kidney transplantation (PKT) and of pretransplant dialysis duration on graft survival among French pediatric kidney transplant recipients. METHODS: We analyzed all first pediatric kidney-only transplantations performed in France between 1993 and 2012. A Cox multivariable model was used to investigate the association of PKT and pretransplant dialysis time with the hazard of graft failure defined as death, return to dialysis, or retransplant, whichever occurred first. RESULTS: Patients (n = 1911) were included, of which 380 (19.8%) received a PKT. Median time of follow-up was 7.0 y. PKT was associated with a 55% reduction of the hazard of graft failure at any time after KT compared with patients transplanted after dialysis (hazard ratio, 0.45; 95% confidence interval, 0.33-0.62), after adjustment for recipient sex and age, primary kidney disease, donor age and type (living or deceased donor), number of HLA mismatches, cold ischemia time, and year of transplantation. A reduction of the hazard of graft failure was found in PKT whatever the compared duration of dialysis, even when <6 mo and whatever the dialysis modality. Results were similar in multiple sensitivity analyses. CONCLUSIONS: In France, PKT among pediatric patients is associated with a better graft survival when compared with KT after dialysis, even when <6 mo. Based on these findings, we suggest that PKT should be considered as the treatment of choice for children with end-stage kidney disease.

Quality of life of transplanted children and their parents: a cross-sectional study.

BACKGROUND: Transplantation is a saving therapeutic that has heavy consequences. The quality of life (QoL) of transplanted children and their parents has been little studied and should help physicians better manage these patients. The objectives of the study were to assess: (1) the QoL of transplanted children and parents and compare it with that of children with other chronic conditions associated with long-term consequences, and (2) potential variables modulating the QoL. METHODS: This cross-sectional study was performed in a multidisciplinary paediatric unit (Timone Hospital, Marseille, France). Children were less than 18 years old; had a liver, kidney or heart transplant; and had a time since transplantation of 1-10 years. Socio-demographics and clinical data were recorded from medical forms. The QoL was assessed using the VSP-A (Vécu et Santé Perçue de l'Adolescent et de l'Enfant) and the WhoQoL self-reported questionnaires. RESULTS: Forty-five families were included (response rate: 76%). The transplanted organs were the liver for 20 children, the kidney for 15 children, and the heart for 10 children. The QoL of transplanted children reported by their parents was better than that of children with inborn errors of metabolism and similar to that of childhood leukaemia survivors. The QoL of parents of transplanted children was better than that of parents of children with inborn errors of metabolism and did not differ from French norms. The QoL did not differ according to the nature of the transplanted organ, sex or the main sociodemographic data. The main modulators decreasing QoL were residual treatment level, medications switch and the presence of another regular treatment. CONCLUSION: Transplanted children and their families reported a fairly preserved QoL compared to children with other chronic health conditions. Special attention should be given to QoL modulators related to therapeutic management (medication switches, regular treatments) that might be amenable to improve the QoL. Trial registration Ethics committee of Aix-Marseille University, France (reference number: 2014-08-04-03, 24/4/2015; https://www.univ-amu.fr/fr/public/comite-dethique ).

Covid-19 in liver transplant recipients: the French SOT COVID registry.

BACKGROUND: Notwithstanding the ongoing coronavirus disease-2019 (Covid-19) pandemic, information on its clinical presentation and prognosis in organ transplant recipients remains limited. The aim of this registry-based observational study was to report the characteristics and clinical outcomes of liver transplant (LT) recipients included in the French nationwide Registry of Solid Organ Transplant Recipients with Covid-19. METHODS: COVID-19 was diagnosed in patients who had a positive PCR assay for SARS-CoV-2 or in presence of typical lung lesions on imaging or specific SARS-CoV-2 antibodies. Clinical and laboratory characteristics, management of immunosuppression, treatment for Covid-19, and clinical outcomes (hospitalization, admission to intensive care unit, mechanical ventilation, or death) were recorded. RESULTS: Of the 104 patients, 67 were admitted to hospital and 37 were managed at home (including all 13 children). Hospitalized patients had a median age of 65.2 years (IQR: 58.1 - 73.2 years) and two thirds were men. Most common comorbidities included overweight (67.3%), hypertension (61.2%), diabetes (50.7%), cardiovascular disease (20.9%) and respiratory disease (16.4%). SARS-CoV-2 infection was identified after a median of 92.8 months (IQR: 40.1 - 194.7 months) from LT. During hospitalization, antimetabolites, mTOR inhibitor, and CNIs were withdrawn in 41.9%, 30.0% and 12.5% of patients, respectively. The composite endpoint of severe Covid-19 within 30 days after diagnosis was reached by 33.0% of the adult patients. The 30-day mortality rate was 20.0%, and 28.1% for hospitalized patients. Multivariate analysis identified that age was independently associated with mortality. CONCLUSION: In our large nationwide study, Covid-19 in LT recipients was associated with a high mortality rate.

COQ6 mutation in patients with nephrotic syndrome, sensorineural deafness, and optic atrophy.

INTRODUCTION: Primary coenzyme Q10 (CoQ10) deficiencies are a group of mitochondrial disorders that has proven responsiveness to replacement therapy. Mutations in enzymes involved in the biosynthesis of CoQ10 genes are associated with these deficits. The clinical presentation of this rare autosomal recessive disorder is heterogeneous and depends on the gene involved. Mutations in the COQ2, COQ6, PDSS2, and ADCK4 genes are responsible for steroid-resistant nephrotic syndrome (SRNS), which is associated with extra-renal symptoms. Previous studies have reported COQ6 mutations in 11 patients from five different families presenting with SRNS and sensorineural deafness. CASE REPORTS: Our study reports the cases of two brothers of Turkish origin with renal failure and sensorineural deafness associated with COQ6 mutations responsible of CoQ10 deficiency. Optical symptoms were present in the eldest, that improved with Idebenone. CONCLUSION/DISCUSSION: For the first time, COQ6 mutation with optical involvement is associated with renal and hearing impairment. Although the response to replacement CoQ10 therapy was difficult to evaluate, we think that this treatment was able to stop the disease progression in both patients, and even to prevent the occurrence/development of optical and neurological impairment in the younger brother. Mitochondrial dysfunction secondary to CoQ10 deficiency should always be suspected in patients with SRNS and extra-renal symptoms. Early recognition of this genetic SRNS is mandatory since SRNS can be avoided by adequate treatment based on CoQ10 supplement or an analogue. All cases of primary CoQ10 deficiency should be treated at an early stage to limit the progression of lesions and prevent the emergence of new symptoms.

Tacrolimus Granules for Oral Suspension as Post-Transplant Immunosuppression in Routine Medical Practice in France: The OPTIMOD Study.

BACKGROUND Different pharmaceutical forms of oral tacrolimus allow tailored administration. The granular formulation facilitates accurate dose adjustment of tacrolimus according to patient characteristics, such as weight, or potential concomitant drug interactions. Currently, there are no data describing the use of tacrolimus granules in transplant recipients in France. MATERIAL AND METHODS OPTIMOD was a 6-month prospective, observational multicenter study that aimed to describe patient characteristics and conditions of use of tacrolimus granules. The 25 participating centers enrolled patients at time of tacrolimus granules initiation and were to collect patient and treatment data at initiation and after 6 months of follow-up. All analyses were descriptive. RESULTS Of 61 patients included, 55.7% were children (mainly kidney graft recipients) and 44.3% were adults (mostly lung graft recipients). Overall, 24.6% of patients (all children) initiated tacrolimus granules immediately post-transplant; the remaining 75.4% converted to tacrolimus granules from ciclosporin or immediate-release tacrolimus hard capsules. The main reasons for initiating tacrolimus granules, irrespective of whether first- or second-line therapy, were to offset potential drug-drug interactions in adults by adjusting dose, and to adapt to the particular needs of children as patients. Most patients (78.7%) underwent ≥1 dose modification during follow-up. Eleven rejection episodes occurred during follow-up, of which none led to graft loss. The adverse-event profile of the tacrolimus granules was similar to that of other tacrolimus formulations and 7 treatment-related adverse events were recorded. CONCLUSIONS Results suggest that tacrolimus granules are well tolerated and effective in preventing transplant rejection when administered in routine practice in France.