Primary disease recurrence—effects on paediatric renal transplantation outcomes

Incidence, risk factors, and outcomes of recurrent focal segmental glomerulosclerosis in pediatric kidney transplant recipients: A systematic review and meta-analysis

BACKGROUND

Focal segmental glomerulosclerosis is the most prevalent acquired kidney disease leading to end-stage renal disease in children and has a propensity for recurring in the transplanted kidney. The recurrence of FSGS after kidney transplantation in children varies greatly. In addition, the risk factors and outcomes of recurrence of FSGS remain controversial. This study evaluated the recurrence rate, risk factors, and prognosis of FSGS after kidney transplantation in order to provide advice and assistance in clinical decision-making for pediatric kidney transplantation.

METHODS

PubMed, Embase, Web of Science, CNKI, and other databases were searched from the establishment of the repository to March 2022. We extracted data on incidence, risk factors, and outcomes.

RESULTS

The results showed that the recurrence rate of primary FSGS in children after renal transplantation was 48% (95% CI 36%-59%) and the recurrence rate of FSGS (all forms) was 35% (95% CI 17%-52%). The graft loss rate of primary FSGS in children after kidney transplantation was 29% (95% CI 17%-42%) and the graft loss rate of FSGS (all forms) was 29% (95% CI 4%-62%). 57% (95% CI 42%-73%) of pediatric patients with recurrent primary FSGS showed complete remission. Risk factor analyses showed that age of onset (SMD .69, 95% CI .20-1.19, p = .006) was related to the recurrence of primary FSGS, whereas the living related donor was not a risk factor for recurrent primary FSGS in pediatrics after kidney transplantation (OR 1.22, 95% CI .48-3.10, p = .674).

CONCLUSIONS

The recurrence rate and graft loss rate of FSGS in children after kidney transplantation were relatively high. Age at onset was associated with a risk for recurrent primary FSGS, whereas the living related donor was not a risk factor for recurrent FSGS in pediatric kidney recipients.

Lupus Nephritis in Children: Novel Perspectives

Childhood-onset systemic lupus erythematosus is an inflammatory and autoimmune condition characterized by heterogeneous multisystem involvement and a chronic course with unpredictable flares. Kidney involvement, commonly called lupus nephritis, mainly presents with immune complex-mediated glomerulonephritis and is more frequent and severe in adults. Despite a considerable improvement in long-term renal prognosis, children and adolescents with lupus nephritis still experience significant morbidity and mortality. Moreover, current literature often lacks pediatric-specific data, leading clinicians to rely exclusively on adult therapeutic approaches. This review aims to describe pediatric lupus nephritis and provide an overview of the novel perspectives on the pathogenetic mechanisms, histopathological classification, therapeutic approach, novel biomarkers, and follow-up targets in children and adolescents with lupus nephritis.

Management and outcomes in children with lupus nephritis in the developing countries

BACKGROUND

Lupus nephritis (LN) has variable prevalence, severity, and outcomes across the world.

OBJECTIVES

This review compares the outcomes of childhood LN in low- and middle-income countries (LMICs) and high-income countries (HICs) and aims to summarize long-term outcomes of pediatric LN from LMICs.

DATA SOURCES

A systematic literature search, conducted in PubMed, EMBASE, and Cochrane database in the last 30-years from January 1992, published in the English language, identified 113 studies including 52 from lower (n = 1336) and upper MICs (n = 3014).

STUDY ELIGIBILITY CRITERIA

Cohort studies or randomized controlled trials, of patients ≤ 18 years of age (or where such data can be separately extracted), with > 10 patients with clinically or histologically diagnosed LN and outcomes reported beyond 12 months were included.

PARTICIPANTS AND INTERVENTIONS

Patients ≤ 18 years of age with clinically or histologically diagnosed LN; effect of an intervention was not measured.

STUDY APPRAISAL AND SYNTHESIS METHODS

Two authors independently extracted data. We separately analyzed studies from developed countries (high income countries; HIC) and developing countries (LMICs). Middle-income countries were further classified as lower and upper MICs. Meta-analyses of data were performed by calculating a pooled estimate utilizing the random-effects model. Test for heterogeneity was applied using I² statistics. Publication bias was assessed using funnel plots.

RESULTS

Kidney remission was similar across MICs and HICs with 1-year pooled complete remission rates of 59% (95% CI 51-67%); one third of patients had kidney flares. The pooled 5-year survival free of stage 5 chronic kidney disease (CKD5) was lower in MICs, especially in lower MICs compared to HICs (83% vs. 93%; P = 0.002). The pooled 5-year patient survival was significantly lower in MICs than HICs (85% vs. 94%; P < 0.001). In patients with class IV LN, the 5-and 10-year respective risk of CKD5 was 14% and 30% in MICs; corresponding risks in HICs were 8% and 17%. Long-term data from developing countries was limited. Sepsis (48.8%), kidney failure (14%), lupus activity (18.1%), and intracranial hemorrhage/infarct (5.4%) were chief causes of death; mortality due to complications of kidney failure was more common in lower MICs (25.6%) than HICs (6.4%).

LIMITATIONS

The review is limited by heterogenous approach to diagnosis and management that has changed over the period spanning the review. World Bank classification based on income might not correlate with the standards of medical care. The overall quality of evidence is low since included studies were chiefly retrospective and single center.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Challenges in LMICs include limited access to pediatric nephrology care, dialysis, increased risk of infection-induced mortality, lack of frequent monitoring, and non-compliance due to cost of therapy. Attention to these issues might update the existing data and improve patient follow-up and outcomes.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO 2022 number: CRD42022359002, available from: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022359002.

Precise clinicopathologic findings for application of genetic testing in pediatric kidney transplant recipients with focal segmental glomerulosclerosis/steroid-resistant nephrotic syndrome

BACKGROUND

Establishing a molecular genetic diagnosis of focal segmental glomerulosclerosis (FSGS)/steroid-resistant nephrotic syndrome (SRNS) can be useful for predicting post-transplant recurrence. Monogenic causes are reportedly present in approximately 20-30% of patients with FSGS/SRNS. However, the characteristics of patients who are likely to have a monogenic cause remain to be determined.

METHODS

Pediatric recipients with SRNS and/or biopsy-proven FSGS who underwent their first kidney transplantation at our center between 1999 and 2019 were analyzed. Patients with secondary FSGS/SRNS were excluded. The recipients were divided into three groups: familial/syndromic, presumed primary, and undetermined FSGS/SRNS. Patients who met all of the following criteria were categorized as having presumed primary FSGS/SRNS: (i) nephrotic syndrome, (ii) complete or partial remission with initial steroid therapy and/or additional immunosuppressive therapies, and (iii) diffuse foot process effacement on electron microscopy in the native kidney biopsy. All patients underwent genetic testing using next-generation sequencing.

RESULTS

Twenty-four patients from 23 families were analyzed in this study. Pathogenic or likely pathogenic variants in FSGS/SRNS-related genes were identified in four of four families, zero of eight families, and 10 of 11 families with familial/syndromic, presumed primary, and undetermined FSGS/SRNS, respectively. Post-transplant recurrence only occurred in patients with presumed primary FSGS/SRNS.

CONCLUSIONS

Our systematic approach based on precise clinicopathological findings including nephrotic syndrome, treatment responses, and diffuse foot process effacement might be useful to differentiate pediatric kidney transplant recipients with FSGS/SRNS who are likely to have a monogenic cause from patients who are not, and to predict post-transplant recurrence. A higher resolution version of the Graphical abstract is available as Supplementary information.

Evaluation of the Effectiveness of Interventions on Nephrolithiasis in Transplanted Kidney

CONTEXT

De Novo nephrolithiasis in renal transplant can have severe consequences since renal transplantation involves a single functioning kidney with medical and anatomical specificities (heterotopic transplantation on iliac vessels, immunosuppressive treatments, and comorbidities).

OBJECTIVE

To systematically review all available evidence on the prevalence of de novo nephrolithiasis in renal transplant, presentation, and stone characteristics, and to report in a meta-analysis the efficacy of stone treatments (extracorporeal shock wave lithotripsy [ESWL], medical treatment, percutaneous nephrolithotomy [PCNL], open surgery, and ureteroscopy).

EVIDENCE ACQUISITION

Medline, Embase, and the Cochrane Library were searched up to November 2021 for all relevant publications reporting the management of de novo nephrolithiasis in renal allografts. The primary outcome was stone-free rate (SFR) at 3 mo. Secondary outcomes included prevalence, stone characteristics (size, density, and composition), symptoms on presentation, need for drainage, complications, and recurrence. Data were narratively synthesized in light of methodological and clinical heterogeneity, and a meta-analysis was performed for SFR. The risk of bias of each included study was assessed.

EVIDENCE SYNTHESIS

We included 37 retrospective studies with 553 patients and 612 procedures; of the 612 procedures 20 were antegrade ureteroscopy, 154 retrograde ureteroscopy, 118 PCNL, 25 open surgery, 155 ESWL, and 140 surveillance/medical treatment. The prevalence of nephrolithiasis in renal transplant was 1.0%. The mean stone size on diagnosis was 11 mm (2-50). The overall SFR at 3 mo was 82%: 96% with open surgery, 95% with antegrade ureteroscopy, 86% with PCNL, 81% with retrograde ureteroscopy, and 75% with ESWL.

CONCLUSIONS

De novo nephrolithiasis in renal transplant is an infrequent condition. A high SFR were obtained with an antegrade approach (ureteroscopy, PCNL, and open approach) that should be considered in renal transplant patients owing to the heterotopic position of the renal graft. The choice of technique was correlated with stone size: generally ureteroscopy and ESWL for stones 11-12 mm (mean stone size) versus PCNL and open surgery for 17-25 mm stones.

PATIENT SUMMARY

De novo nephrolithiasis in renal transplants is an infrequent situation that can have severe consequences on the function of the renal graft. We evaluated the efficacy of each treatment and noted that antegrade approaches (open surgery, percutaneous nephrolithotomy, and antegrade ureteroscopy) were associated with the highest stone-free rate. As opposed to the management of nephrolithiasis in native kidney, an antegrade approach should be considered more in renal transplant patients.

Case report: Eculizumab plus obinutuzumab induction in a deceased donor kidney transplant recipient with DEAP-HUS

The wide-spread use of the anti-complement component 5 monoclonal antibody (moAb) eculizumab has greatly reduced the incidence of relapsing atypical hemolytic uremic syndrome (aHUS) after kidney transplantation (KT). However, the optimal management of aHUS transplant candidates with anti-Complement Factor H (CFH) antibodies remains debated. In these patients, the benefits of chronic eculizumab administration should be weighed against the risk of fatal infections, repeated hospital admissions, and excessive costs. We report the case of a 45-year-old female patient with CFHR1/CFHR3 homozygous deletion-associated aHUS who underwent deceased-donor KT despite persistently elevated anti-CFH antibody titers. As induction and aHUS prophylaxis, she received a combination of eculizumab and obinutuzumab, a humanized type 2 anti-CD20 moAb. The post-operative course was uneventful. After 1-year of follow-up, she is doing well with excellent allograft function, undetectable anti-CFH antibodies, sustained B-cell depletion, and no signs of aHUS activity. A brief review summarizing current literature on the topic is also included. Although anecdotal, our experience suggests that peri-operative obinutuzumab administration can block anti-CFH antibodies production safely and effectively, thus ensuring long-lasting protection from post-transplant aHUS relapse, at a reasonable cost. For the first time, we have demonstrated in vivo that obinutuzumab B-cell depleting properties are not significantly affected by eculizumab-induced complement inhibition.

Response to steroid and immunosuppressive therapies may predict post-transplant recurrence of steroid-resistant nephrotic syndrome

BACKGROUND

Recurrence of SRNS is a major challenge in KT. Several clinical factors, including initial steroid sensitivity, have been associated with increased post-transplant SRNS recurrence risk. However, conflicting data have been reported, possibly due to the heterogeneous pathophysiology of SRNS and the lack of genetic testing of SRNS patients. Furthermore, the response to immunosuppressive therapies has not been evaluated.

METHODS

Seventy patients aged 1-15 years at SRNS onset who underwent KT between 2002 and 2018 were enrolled. Patients with secondary, familial, syndromic, and genetic forms of SRNS and those who were not treated with steroid were excluded. This study aimed to assess the risk factors for post-transplant recurrence, including treatment responses to initial steroid therapy and additional therapies with immunosuppressive agents, rituximab, plasmapheresis, and/or LDL-A.

RESULTS

Data from 36 kidney transplant recipients were analyzed. Twenty-two (61%) patients experienced post-transplant SRNS recurrence, while 14 patients did not. The proportion of patients who achieved complete or partial remission with initial steroid therapy and/or additional therapies with immunosuppressive agents, rituximab, plasmapheresis, and/or LDL-A was significantly higher in the SRNS recurrence group (19/22, 86%) than in the group without SRNS recurrence (6/14, 43%; p = .01).

CONCLUSION

This study suggests that the response to steroid treatment, other immunosuppressive agents, rituximab, plasmapheresis, and/or LDL-A may predict post-transplant SRNS recurrence.

Low-density lipoprotein apheresis for recurrent focal segmental glomerulosclerosis post renal transplant in pediatric patients

Low-density lipoprotein (LDL) apheresis has been shown to improve remission in patients with steroid-resistant nephrotic syndrome (SRNS). Here, we report a case study of two patients who failed apheresis treatment for SRNS and required transplant with subsequent recurrence of nephrotic syndrome and response to apheresis treatment. Two patients were treated with 12 sessions of LDL apheresis for SRNS without improvement and subsequently required renal transplantation. The first patient received an ABO-incompatible kidney transplant requiring plasma exchange (PE) with subsequent recurrence of focal segmental glomerulosclerosis. The second patient also received a renal transplant after treatment failure and subsequently developed recurrence of nephrotic syndrome in the transplanted kidney. Both patients underwent repeat therapy with lipoprotein apheresis. The first patient underwent lipoprotein apheresis after completing PE with significant improvement in serum creatinine and urine protein creatinine ratio. Three years later, he continued to do well and remains in remission. The second patient also responded well to repeat therapy with lipoprotein apheresis and had significant improvement with a urine protein creatinine ratio of 0.8 and a serum creatinine of 0.9 mg/dL 6 months after transplant. Lipoprotein apheresis was able to result in remission of nephrotic syndrome in these patients with posttransplant recurrence of disease. This is the first report of patients not responding to treatment pretransplant but responding posttransplant. Lipoprotein apheresis should be considered in patients with recurrence of nephrotic syndrome after renal transplantation even with a history of treatment failure prior to transplantation.

Application of adrenocorticotropic hormone in recurrent focal segmental glomerulosclerosis post-transplantation: A case report and literature review

BACKGROUND

The recurrence rate of focal segmental glomerulosclerosis (FSGS) post-renal transplantation is as high as 30%-50%. However, the pathogenesis is unclear. At present, there is no unified standard for the treatment of recurrent FSGS post-transplantation. Its treatment is full of risks and challenges.

METHODS

We report a child with recurrent FSGS with massive proteinuria 6~9 g/m² /day and resistance to plasma exchange (PE) and rituximab (RTX). On the basis of receiving anti-rejection therapy of prednisone, tacrolimus, and mycophenolate mofetil (MMF), we treated the child with adrenocorticotropic hormone (ACTH), and reviewed the literature on the application of ACTH in the recurrence of FSGS post-transplantation.

RESULTS

After 1 year of treatment with ACTH, the patient's urinary protein decreased and fluctuated between 0.6 and 1.1 g/m² /day. The albumin (ALB) and cholesterol (CHOL) returned to the normal range. The patient achieved complete remission after 19 months of ACTH treatment and maintained until now. There was no obvious adverse reaction. Literature review showed that up to February 2021, a total of 8 studies showed the use of ACTH in kidney transplant patients, and all the patients in the study achieved remission.

CONCLUSIONS

ACTH is a potential option for treating recurrent FSGS post-transplantation with fewer side effects and relatively safe for patients. However, further evaluation is needed to better adapt to different populations.

Steroid avoidance/withdrawal and maintenance immunosuppression in pediatric kidney transplantation

BACKGROUND

Corticosteroids have been an integral part of maintenance immunosuppression for pediatric kidney transplantation. However, prolonged steroid therapy is associated with significant toxicities resulting in several SW/avoidance strategies in recent years.

METHOD/OBJECTIVE

This comprehensive review aims to discuss steroid-related toxicities and the safety, efficacy, and benefit of steroid avoidance/withdrawal immunosuppression in pediatric kidney transplant recipients.

RESULTS

Initial studies of SW/avoidance conducted in the setting of CSA and AZA showed an increased incidence of AR but no increase in graft loss or mortality with SW/avoidance maintenance immunosuppression. Studies performed under modern immunosuppression (induction therapy, Tac, and MMF) show no significant increase in AR or graft loss with SW/avoidance immunosuppression. Furthermore, SW/avoidance immunosuppression is associated with significant improvement in growth, BMI, BP control, and lipid profile in pediatric kidney transplant recipients. Despite these data, SW/avoidance remains controversial, and only 40% of pediatric kidney transplant recipients in the United States are currently on SW/avoidance maintenance immunosuppression.

CONCLUSION

SW/avoidance maintenance immunosuppression is safe and associated with fewer side effects compared with steroid-inclusive maintenance immunosuppression in pediatric kidney transplant recipients.

OUP accepted manuscript

Podocytopathies are glomerular disorders in which podocyte injury drives proteinuria and progressive kidney disease. They encompass a broad spectrum of aetiologies, resulting in pathological pictures of minimal-changes, focal segmental glomerulosclerosis, diffuse mesangial sclerosis or collapsing glomerulopathy. Despite improvement in classifying podocytopathies as a distinct group of disorders, the histological definition fails to capture the relevant biological heterogeneity underlying each case, manifesting as extensive variability in disease progression and response to therapies. Increasing evidence suggests that podocytopathies can result from a single causative factor or a combination of multiple genetic and/or environmental risk factors with different relative contributions, identifying complex physiopathological mechanisms. Consequently, the diagnosis can still be challenging. In recent years, significant advances in genetic, microscopy and biological techniques revolutionized our understanding of the molecular mechanisms underlying podocytopathies, pushing nephrologists to integrate innovative information with more conventional data obtained from kidney biopsy in the diagnostic workflow. In this review, we will summarize current approaches in the diagnosis of podocytopathies, focusing on strategies aimed at elucidating the aetiology underlying the histological picture. We will provide several examples of an integrative view of traditional concepts and new data in patients with suspected podocytopathies, along with a perspective on how a reclassification could help to improve not only diagnostic pathways and therapeutic strategies, but also the management of disease recurrence after kidney transplantation. In the future, the advantages of precision medicine will probably allow diagnostic trajectories to be increasingly focused, maximizing therapeutic results and long-term prognosis.

Long-Term Transplantation Outcomes in Patients With Primary Hyperoxaluria Type 1 Included in the European Hyperoxaluria Consortium (OxalEurope) Registry

Introduction

In primary hyperoxaluria type 1 (PH1), oxalate overproduction frequently causes kidney stones, nephrocalcinosis, and kidney failure. As PH1 is caused by a congenital liver enzyme defect, combined liver–kidney transplantation (CLKT) has been recommended in patients with kidney failure. Nevertheless, systematic analyses on long-term transplantation outcomes are scarce. The merits of a sequential over combined procedure regarding kidney graft survival remain unclear as is the place of isolated kidney transplantation (KT) for patients with vitamin B6-responsive genotypes.

Methods

We used the OxalEurope registry for retrospective analyses of patients with PH1 who underwent transplantation. Analyses of crude Kaplan–Meier survival curves and adjusted relative hazards from the Cox proportional hazards model were performed.

Results

A total of 267 patients with PH1 underwent transplantation between 1978 and 2019. Data of 244 patients (159 CLKTs, 48 isolated KTs, 37 sequential liver–KTs [SLKTs]) were eligible for comparative analyses. Comparing CLKTs with isolated KTs, adjusted mortality was similar in patients with B6-unresponsive genotypes but lower after isolated KT in patients with B6-responsive genotypes (adjusted hazard ratio 0.07, 95% CI: 0.01–0.75, P = 0.028). CLKT yielded higher adjusted event-free survival and death-censored kidney graft survival in patients with B6-unresponsive genotypes (P = 0.025, P < 0.001) but not in patients with B6-responsive genotypes (P = 0.145, P = 0.421). Outcomes for 159 combined procedures versus 37 sequential procedures were comparable. There were 12 patients who underwent pre-emptive liver transplantation (PLT) with poor outcomes.

Conclusion

The CLKT or SLKT remains the preferred transplantation modality in patients with PH1 with B6-unresponsive genotypes, but isolated KT could be an alternative approach in patients with B6-responsive genotypes.

Recurrent Glomerular Diseases in Renal Transplantation with Focus on Role of Electron Microscopy

Background

The common causes of renal transplant complications include active or chronic rejection process, infections, and toxicity but also recurrent or de novo diseases, which play an important role in affecting long-term graft function or graft loss.

Summary

Recurrent disease in renal transplantation is defined as recurrence of the original kidney disease leading to end-stage kidney disease. They comprise a heterogeneous group of predominantly glomerular and some tubulointerstitial and vascular lesions, which include primary kidney diseases (e.g., focal segmental glomerulosclerosis, membranous glomerulonephritis, and IgA nephropathy) or those secondary to systemic autoimmune, metabolic, and infectious processes that can range from subclinical to clinically overt acute, subacute, or chronic clinical presentations. In addition to the knowledge of prior renal disease and routine/periodic serum and urine testing for kidney function, a complete transplant renal biopsy examination is essential in the identification and differentiation of these diseases. The time of onset and severity of these diseases depend on the underlying etiopathogenetic mechanisms and the varied rates of recurrence in the early or late posttransplant period, often being modified by the current immunosuppressive protocols and other donor and recipient predisposing characteristics.

Key Messages

Transplant kidney biopsy findings provide diagnostic accuracy and prognostic information regarding the potential for reversibility along with detection of unsuspected or clinically symptomatic recurrent diseases, with any concomitant rejection process or toxicity, for appropriate therapeutic decision-making. Routine electron microscopy in transplant kidney biopsies is a valuable tool in recognizing fully developed or early/subtle features of evolving recurrent diseases, often during the subclinical phases, in for cause or surveillance allograft biopsies.

LDL-apheresis-induced remission of focal segmental glomerulosclerosis recurrence in pediatric renal transplant recipients

BACKGROUND

Focal segmental glomerulosclerosis (FSGS) in pediatric patients is typically difficult to treat and will progress to end-stage renal disease (ESRD) in about 10% of cases. Following kidney transplantation, FSGS can recur in up to 56% of renal allografts-with a near 100% recurrence in subsequent transplants.

METHODS

Four different pediatric centers across the USA and the UK employed a protocol using LDL-apheresis (LDL-A) and pulse solumedrol to treat recurrent FSGS after transplantation in seven patients. All the patients included in this series demonstrated immediate, or early, recurrence of FSGS, which clinically presented as nephrotic-range proteinuria within hours to days after implantation of the kidney.

RESULTS

All patients experienced reductions in urinary protein to creatinine ratios resulting in partial or complete remission. All patients demonstrated improvements in their estimated GFRs at their most recent follow-up since LDL-A discontinuation.

CONCLUSIONS

This case series describes the successful treatment, across four different pediatric centers, of seven pediatric patients with recurrent post-transplant FSGS using the Liposorber® LA-15 in combination with pulse solumedrol.

Hemolytic uremic syndrome in a developing country: Consensus guidelines

BACKGROUND

Hemolytic uremic syndrome (HUS) is a leading cause of acute kidney injury in children. Although international guidelines emphasize comprehensive evaluation and treatment with eculizumab, access to diagnostic and therapeutic facilities is limited in most developing countries. The burden of Shiga toxin-associated HUS in India is unclear; school-going children show high prevalence of anti-factor H (FH) antibodies. The aim of the consensus meeting was to formulate guidelines for the diagnosis and management of HUS in children, specific to the needs of the country.

METHODS

Four workgroups performed literature review and graded research studies addressing (i) investigations, biopsy, genetics, and differential diagnosis; (ii) Shiga toxin, pneumococcal, and infection-associated HUS; (iii) atypical HUS; and (iv) complement blockade. Consensus statements developed by the workgroups were discussed during a consensus meeting in March 2017.

RESULTS

An algorithm for classification and evaluation was developed. The management of Shiga toxin-associated HUS is supportive; prompt plasma exchanges (PEX) is the chief therapy in patients with atypical HUS. Experts recommend that patients with anti-FH-associated HUS be managed with a combination of PEX and immunosuppressive medications. Indications for eculizumab include incomplete remission with plasma therapy, life-threatening features, complications of PEX or vascular access, inherited defects in complement regulation, and recurrence of HUS in allografts. Priorities for capacity building in regional and national laboratories are highlighted.

CONCLUSIONS

Limited diagnostic capabilities and lack of access to eculizumab prevent the implementation of international guidelines for HUS in most developing countries. We propose practice guidelines for India, which will perhaps be applicable to other developing countries.

Whole-Exome Sequencing Enables a Precision Medicine Approach for Kidney Transplant Recipients

BACKGROUND

Whole-exome sequencing (WES) finds a CKD-related mutation in approximately 20% of patients presenting with CKD before 25 years of age. Although provision of a molecular diagnosis could have important implications for clinical management, evidence is lacking on the diagnostic yield and clinical utility of WES for pediatric renal transplant recipients.

METHODS

To determine the diagnostic yield of WES in pediatric kidney transplant recipients, we recruited 104 patients who had received a transplant at Boston Children's Hospital from 2007 through 2017, performed WES, and analyzed results for likely deleterious variants in approximately 400 genes known to cause CKD.

RESULTS

By WES, we identified a genetic cause of CKD in 34 out of 104 (32.7%) transplant recipients. The likelihood of detecting a molecular genetic diagnosis was highest for patients with urinary stone disease (three out of three individuals), followed by renal cystic ciliopathies (seven out of nine individuals), steroid-resistant nephrotic syndrome (nine out of 21 individuals), congenital anomalies of the kidney and urinary tract (ten out of 55 individuals), and chronic glomerulonephritis (one out of seven individuals). WES also yielded a molecular diagnosis for four out of nine individuals with ESRD of unknown etiology. The WES-related molecular genetic diagnosis had implications for clinical care for five patients.

CONCLUSIONS

Nearly one third of pediatric renal transplant recipients had a genetic cause of their kidney disease identified by WES. Knowledge of this genetic information can help guide management of both transplant patients and potential living related donors.

Membranoproliferative glomerulonephritis and C3 glomerulopathy in children: change in treatment modality? A report of a case series

Background

Membranoproliferative glomerulonephritis (MPGN) with immune complexes and C3 glomerulopathy (C3G) in children are rare and have a variable outcome, with some patients progressing to end-stage renal disease (ESRD). Mutations in genes encoding regulatory proteins of the alternative complement pathway and of complement C3 (C3) have been identified as concausative factors.

Methods

Three children with MPGN type I, four with C3G, i.e. three with C3 glomerulonephritis (C3GN) and one with dense deposit disease (DDD), were followed. Clinical, autoimmune data, histological characteristics, estimated glomerular filtration rate (eGFR), proteinuria, serum C3, genetic and biochemical analysis were assessed.

Results

The median age at onset was 7.3 years and the median eGFR was 72 mL/min/1.73 m². Six children had marked proteinuria. All were treated with renin-angiotensin-aldosterone system (RAAS) blockers. Three were given one or more immunosuppressive drugs and two eculizumab. At the last median follow-up of 9 years after diagnosis, three children had normal eGFR and no or mild proteinuria on RAAS blockers only. Among four patients without remission of proteinuria, genetic analysis revealed mutations in complement regulator proteins of the alternative pathway. None of the three patients with immunosuppressive treatment achieved partial or complete remission of proteinuria and two progressed to ESRD and renal transplantation. Two patients treated with eculizumab revealed relevant decreases in proteinuria.

Conclusions

In children with MPGN type I and C3G, the outcomes of renal function and response to treatment modality show great variability independent from histological diagnosis at disease onset. In case of severe clinical presentation at disease onset, early genetic and biochemical analysis of the alternative pathway dysregulation is recommended. Treatment with eculizumab appears to be an option to slow disease progression in single cases.

Outcome of kidney transplantation in pediatric patients with ANCA-associated glomerulonephritis: a single-center experience

OBJECTIVES

Data on kidney transplant outcomes for pediatric patients with end-stage renal disease (ESRD) secondary to anti-neutrophil cytoplasmic antibody glomerulonephritis (ANCA GN), particularly granulomatosis with polyangiitis (GPA) and microscopic polyangiitis (MPA), is limited. We describe our experience of kidney transplantation in pediatric ANCA GN patients.

METHODS

We performed a retrospective review of patients with ANCA GN who developed ESRD and were transplanted at a single center between the years 2000 and 2014.

RESULTS

Since 2000, there were seven pediatric patients with ANCA GN (four MPA) transplanted. Mean age at ANCA GN diagnosis was 11.8 ± 2.8 (range, 7.2-15.4) years. All seven were ANCA (three anti-PR3/four anti-MPO) positive. Estimated glomerular filtration rate (eGFR) at diagnosis was 11.7 ± 6.3 ml/min/1.73 m². All received steroids and cyclophosphamide and three (23.3%) received plasma exchange. Six were dialysis dependent by 6 months post diagnosis. Time from diagnosis to transplant was 30 ± 12 (range, 17-48) months. Six of the seven received a deceased donor transplant. All patients received induction therapy and standard maintenance immunosuppression post transplant. Median duration of follow-up post transplantation was 27 months (range, 13-88 months). Median eGFR at last follow-up was 77 ml/min/1.73 m² (range, 7.9-83.5). One patient lost her transplant to acute cellular rejection following non-adherence to immunosuppression after 21 months of stable transplant function. No patient had recurrence of vasculitis, either renal or extra-renal.

CONCLUSIONS

Short-term patient and allograft survival in pediatric patients with ESRD secondary to ANCA GN seems excellent, with no recurrence of vasculitis post transplant in this small cohort.

Improved Fetal Hemoglobin With mTOR Inhibitor-Based Immunosuppression in a Kidney Transplant Recipient With Sickle Cell Disease

Fetal hemoglobin induction is a key point in the management of sickle cell disease (SCD). We report the case of a kidney transplant recipient with SCD who was treated with everolimus, a mammalian target of rapamycin inhibitor. At 10 months after initiating therapy, the patient's fetal hemoglobin level was dramatically increased (from 4.8% to 15%) and there was excellent tolerance to treatment.

C3 glomerulopathy and eculizumab: a report on four paediatric cases

BACKGROUND

Eculizumab may be used to treat C3-glomerulopathy (C3G), a rare but severe glomerular disease.

DIAGNOSIS AND TREATMENT

Patients 1, 2 and 3 were diagnosed with nephritic syndrome with alternative complement pathway activation (low C3, C3Nef-positive) and C3G at the age of 9, 13 and 12 years, respectively. Treatment with eculizumab normalized proteinuria within 1, 2 and 7 months, respectively. Proteinuria relapsed when eculizumab was withdrawn, but the re-introduction of eculizumab normalized proteinuria. Patient 4 was diagnosed with C3G at 9 years of age, with progression to end-stage renal disease within 2 years, followed by a first renal transplantation (R-Tx) with early disease recurrence and graft loss within 39 months. After a second R-Tx, she rapidly presented with biological and histological recurrence: therapy with eculizumab was started, with no effect on proteinuria after 5 months, in a complex clinical setting (i.e. association of C3G recurrence, humoral rejection and BK nephritis). Eculizumab was withdrawn due to multiple viral reactivations, but the re-introduction of the drug a few months later enabled a moderate decrease in proteinuria.

CONCLUSION

These cases illustrate the efficacy of eculizumab, at least on native kidneys, in paediatric C3G. However, larger international studies are warranted to confirm the benefit and safety of eculizumab therapy.

Optimal management of primary focal segmental glomerulosclerosis in adults

Focal segmental glomerulosclerosis (FSGS) is a frequent glomerular kidney disease that is revealed by proteinuria or even nephrotic syndrome. A diagnosis can be established from a kidney biopsy that shows focal and segmental glomerulosclerosis. This histopathological lesion may be caused by a primary podocyte injury (idiopathic FSGS) but is also associated with other pathologies (secondary FSGS). The first-line treatment for idiopathic FSGS with nephrotic syndrome is a prolonged course of corticosteroids. However, steroid resistance or steroid dependence is frequent, and despite intensified immunosuppressive treatment, FSGS can lead to end-stage renal failure. In addition, in some cases, FSGS can recur on a graft after kidney transplantation: an unidentified circulating factor may be implicated. Understanding of its physiopathology is unclear, and it remains an important challenge for the scientific community to identify a specific diagnostic biomarker and to develop specific therapeutics. This study reviews the treatment of primary FSGS and the recurrence of FSGS after kidney transplantation in adults.

Pediatric combined liver-kidney transplantation: a single-center experience of 18 cases

BACKGROUND

Experience in combined liver-kidney transplantation (CLKT) in children is limited.

METHODS

We conducted a retrospective study of all pediatric CLKTs performed at our medical institution between 1992 and 2013.

RESULTS

We identified 18 pediatric patients (9 girls) who had undergone CLKT at our institution during the study period. The median age [range] and body weight [range] of this patient group was 3.6 [1.0-18.6] years and 13 [10-40] kg, respectively; 11 patients weighed <15 kg at the time of CLKT. Indications for CLKT were primary hyperoxaluria (PH1; n = 14), association of hepatic fibrosis and end-stage renal disease (n = 3) and methylmalonic acidemia (n = 1). In the early postoperative period, eight patients required dialysis. Median stay in the pediatric intensive care unit was 10 [6-29] days. One patient died from cardiovascular disease 10 years after CLKT. There were no liver graft losses despite six acute liver rejection episodes, whereas four kidney grafts were lost. At last follow-up (6 [0.5-21] years) for patients with a functioning renal graft, the glomerular filtration rate was 71 [26-146] mL/min/1.73 m(2). In PH1 patients, urine oxalate normalized in six patients within 3 years after CLKT, but three patients still presented with elevated oxaluria at 1, 2 and 3 years after CLKT.

CONCLUSIONS

Pediatric CLKT provides encouraging results in the long term, even in the youngest patients.

Rituximab is not a "magic drug" in post-transplant recurrence of nephrotic syndrome

Pediatric patients with end-stage renal failure due to severe drug-resistant nephrotic syndrome are at risk of rapid recurrence after renal transplantation. Treatment options include plasmapheresis, high-dose of cyclosporine A/methylprednisolone and more recently-rituximab (anti-B CD20 monoclonal depleting antibody). We report five patients with immediate (1-2 days) post-transplant recurrence of nephrotic syndrome, treated with this kind of combined therapy including 2-4 weekly doses of 375 mg/m(2) of rituximab. Only two (of five) patients have showed full long-term remission, while the partial remission was seen in two cases, and no clinical effect at all was achieved in one patient. The correlation between B CD19 cells depletion and clinical effect was present in two cases only. Severe adverse events were present in two patients, including one fatal rituximab-related acute lung injury.

CONCLUSION

The anti-CD20 monoclonal antibody may be not effective in all pediatric cases of rapid post-transplant recurrence of nephrotic syndrome, and benefit/risk ratio must be carefully balanced on individual basis before taking the decision to use this protocol.

WHAT IS KNOWN

• nephrotic syndrome may recur immediately after renal transplantation • plasmapheresis combined with pharmacotherapy is used as rescue management • rituximab was reported as effective drug both in primary and post-transplant nephrotic syndrome What is New: • rituximab may not be effective is several cases of post-transplant nephrotic syndrome due to variety of underlying mechanisms of the disease, which may be or not be responsive to this drug • there may be no correlation between drug-induced depletion of specific B cells and clinical effect; this might suggest B-cell independent manner of rituximab action.

Recurrence of Focal and Segmental Glomerulosclerosis After Transplantation

Focal segmental glomerulosclerosis, which is a common glomerular disorder, manifests clinically with a nephrotic syndrome and has a high propensity for recurrence after kidney transplantation. The pathophysiology is currently unknown, and podocytes appear to be the target of one or several circulating factor(s) that lead to the recurrence of proteinuria after kidney transplantation. Identifying these circulating factor(s) and cells involved in its synthesis remains elusive; however, recently, our research on podocyte cytoskeleton biology has opened a new era of treatment. This review will highlight recent progress in the physiopathology of focal segmental glomerulosclerosis recurrence after transplantation and its treatment.

Post-Transplant Recurrence of Focal Segmental Glomerulosclerosis in a Child With Heterozygous Mutations in NPHS1 and NPHS2

Renal transplantation is the optimal renal replacement therapy (RRT) in children, but some primary diseases can recur after transplantation, and recurrence accounts for a significant proportion of graft losses, being second only to acute rejection. The risk of disease recurrence is highest among patients with idiopathic focal segmental glomerulosclerosis (FSGS), presumably due to a circulating permeability factor. Less is clear about the genetic forms of FSGS, where the data regarding the frequency of recurrence are rather conflicting. We present a 12-year-old girl with rapidly progressive FSGS and end-stage renal disease in her native kidneys associated with heterozygous mutations in NPHS1 and in NPHS2, suffering from early post-transplant recurrence. On the basis of reviewed literature, and until further and more conclusive evidence considering pathogenicity is provided, we propose that FSGS patients with heterozygous mutations in NPHS1 or NPHS2 should be considered as having idiopathic FSGS, and post-transplant recurrence should be anticipated.

Recurrence and Treatment after Renal Transplantation in Children with FSGS

Focal segmental glomerulosclerosis (FSGS) is a common cause of end-stage renal disease and a common pathologic diagnosis of idiopathic nephrotic syndrome (NS), especially in steroid-resistant cases. FSGS is known to recur after kidney transplantation, frequently followed by graft loss. However, not all patients with FSGS suffer from recurrence after kidney transplantation, and genetic and secondary FSGS have a negligible risk of recurrence. Furthermore, many cases of recurrence achieve remission with the current management of recurrence (intensive plasmapheresis/immunosuppression, including rituximab), and other promising agents are being evaluated. Therefore, a pathologic diagnosis of FSGS itself should not cause postponement of allograft kidney transplantation. For patients with a high risk of recurrence who presented with classical symptoms of NS, that is, severe edema, proteinuria, and hypoalbuminemia, close monitoring of proteinuria is necessary, followed by immediate, intensive treatment for recurrence.

Pediatric combined liver-kidney transplantation: a 2015 update

PURPOSE OF REVIEW

The experience of combined liver-kidney transplantation (CLKT) is limited in pediatric populations. This strategy is, however, required in specific diseases such as metabolic diseases (namely primary hyperoxaluria type one and methylmalonic acidemia), autosomal recessive polycystic kidney disease, miscellaneous ciliopathies and atypical hemolytic uremic syndrome.

RECENT FINDINGS

Different series and registry studies have confirmed the feasibility of pediatric CLKT with encouraging results in the long term, even in the youngest and smallest patients, provided that highly trained multidisciplinary teams are involved in this global management. As such, the long-term outcomes after CLKT are currently comparable to that of isolated liver or kidney transplantations, even though the immediate postoperative period remains challenging.

SUMMARY

Some questions remain nevertheless unanswered, such as the respective place of combined versus sequential liver-kidney transplantation, especially in primary hyperoxaluria and autosomal recessive polycystic kidney disease. The aim of this review was therefore to provide a 2015 update on pediatric CLKT. In the future, international collaborative studies and registries may help to improve our knowledge of this rare and still highly challenging technique.