Immune Desensitization Allows Pediatric Blood Group Incompatible Kidney Transplantation

Successful ABO and HLA incompatible kidney transplantation in children in the UK

BACKGROUND

There is increasing evidence of good short-term and medium-term outcomes of ABO incompatible (ABOi) and HLA incompatible (HLAi) kidney transplantation with pre-transplant positive crossmatches in paediatric practice. However, there remain concerns regarding the higher risks of infective complications and antibody-mediated rejections. The aim of our study is to show longer-term follow-up on all ABOi and HLAi paediatric kidney transplant recipients (pKTR) in the UK.

METHODS

Questionnaires specifying kidney transplant type, desensitisation requirement and kidney allograft function were sent to 13 paediatric nephrology centres that performed kidney transplantation in children and young people under 18 years of age who received an ABOi and/or HLAi transplant between 1 January 2006 and 31 December 2016. Patient and kidney allograft survival were compared between ABOi, HLAi and ABO/HLA compatible (ABOc/HLAc) groups.

RESULTS

Among 711 living donor kidney transplants performed in the UK, 23 were ABOi and 6 were HLAi. Patient survival was 87%, 100% and 96% in ABOi, HLAi and ABOc/HLAc groups, respectively, at median follow-up of 6.8 (3.6-14.0) years post-transplant. Death-censored kidney allograft survival was 100% in all 3 groups at last follow-up. There were no cases of primary non-function in ABOi or HLAi groups, but 2% in the ABOc/HLAc group. There was one reported case of Epstein-Barr viral-induced post-transplant lymphoproliferative disorder.

CONCLUSION

Longer term follow-up has shown that ABOi and HLAi kidney transplantation are feasible for pKTR where no compatible donors are available, and that minimising desensitisation should be achieved where possible. A higher resolution version of the Graphical abstract is available as Supplementary information.

Overcoming limits: First ABO incompatible living donor paired kidney transplant in an hypersensitized pediatric recipient in Spain

INTRODUCTION

HLA sensitization is a growing problem in children awaiting kidney transplantation. In some cases, finding an immunologically compatible donor entails contemplating the option of an ABO incompatible transplant or paired transplant.

METHODS

Patient with genetic nephrotic syndrome and progressive chronic kidney disease, with a previous thrombosis of a first kidney transplant, resulting hypersensitized and remaining for a long-time on hemodialysis. Despite a desensitization strategy, family members were incompatible and deceased donation options must be ruled out due to the presentation of donor-specific antibodies (DSA). After 4 years, the possibility arises to perform a kidney paired transplant with a 62-year-old woman with an incompatible blood group. Although the current cytotoxicity- and cell-based crossmatches were negative, history of DSA were recorded.

RESULTS

An intensive ABO and HLA desensitization protocol was performed in order to combat the isohemagglutinin antibodies and on the memory-HLA, based on rituximab, apheresis sessions, and immunoglobulins. Despite the donor being older in terms of pediatric transplantation, the donor-recipient weight difference, and immunological risk, the transplant was completed successfully. Maintenance of titration of up to 1/2 was confirmed after 3 weeks post-transplant (IgM and IgG). Kidney biopsy at 2 weeks and 6 months without signs of rejection. The patient is currently 12 months post-transplant and has not presented any signs of transplant rejection and has proper renal function.

CONCLUSIONS

Kidney paired transplantation is an excellent solution for hypersensitized children, and ABO incompatibility can be considered to increase their options to find a good donor, without thereby obtaining worse results.

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

Role of therapeutic apheresis in the treatment of pediatric kidney diseases

Therapeutic apheresis utilizes apheresis procedures in the treatment of a variety of conditions including kidney disease. Therapeutic plasma exchange (TPE) is the most common modality employed with the rationale of rapid reduction of a pathogenic substance distributed primarily in the intravascular compartment; however other techniques which adsorb such pathogenic substances or alter the immune profile have been utilized in diseases affecting native and transplanted kidneys. This article discusses the modalities and technical details of therapeutic apheresis and summarizes its role in individual diseases affecting the kidney. Complications related to pediatric apheresis procedures and specifically related to apheresis in kidney disease are also discussed. Though therapeutic apheresis modalities are employed frequently in children with kidney disease, most experiences are extrapolated from adult studies. International and national registries need to be established to elucidate the role of apheresis modalities in children with kidney disease.

Early relapse of atypical hemolytic uremic syndrome following ABO-incompatible living-related pediatric kidney re-transplant successfully treated with eculizumab

BACKGROUND

A 3-year-old girl with clinical features of atypical HUS (complement Factor I mutation inherited from an asymptomatic mother and Factor H autoantibodies) was treated with plasma exchange, progressed to kidney failure (KF) aged 4 years, and received an en bloc kidney DCD transplant aged 8 years with primary graft non-function necessitating transplant nephrectomy at the time of transplantation. She subsequently underwent re-transplantation from her father. This is a retrospective study of electronic patient records and medical notes.

CASE-DIAGNOSIS/TREATMENT

A 9-year-old girl received an ABO-incompatible (ABOi) living-related kidney transplant from her father with recipient and donor blood groups of O and A, respectively, with baseline recipient anti-A titers 1:128 reducing to 1:4 at the time of transplant with B lymphocyte depletion with rituximab and four sessions of immunoadsorption. Six hours post-transplant, she had recurrence of aHUS and received the first dose of eculizumab. She continues on monthly home eculizumab infusions with stable kidney allograft function and negative anti-A titers 7 years post-kidney transplantation.

CONCLUSIONS

This is the first report of a pediatric high-risk ABOi living-related kidney transplantation in whom early relapse of aHUS was successfully treated with eculizumab with good long-term patient and allograft outcome.

UK national study of barriers to renal transplantation in children

AIMS

To investigate access to paediatric renal transplantation and examine potential barriers within the process.

METHODS

Cross-sectional, multicentre, observational study where paediatric nephrology centres in the UK were requested to provide data on transplantation plans for all children (<18 years) with end-stage kidney disease (ESKD).

RESULTS

308 children with ESKD were included in this study from 12 out of 13 UK paediatric nephrology centres. 139 (45%) were being prepared for living donor transplantation and 82 (27%) were listed for deceased donor transplantation. The most common cited factors delaying transplantation from occurring in children were disease factors (36%), donor availability (27%) and size of the child (20%). Psychosocial factors were listed as a barrier in 19% of children.

CONCLUSIONS

In this study we have documented the main barriers to renal transplantation in children. Some identified factors may be modifiable through local or national intervention, including donor availability and patient psychosocial factors.

ABO-incompatible pediatric kidney transplantation without antibody removal

BACKGROUND

Because of the severe shortage of suitable deceased donors, ABO-incompatible living donor kidney transplantation (ABOi LDKT) is performed even in pediatric recipients in Japan. We performed pediatric ABOi LDKT using rituximab without anti-A/B antibody removal.

METHODS

Thirteen pediatric recipients (mean age 7.4, range 3.4-15.7, four females) whose baseline anti-A/B IgG titers were ≤ × 64 underwent ABOi LDKT without antibody removal and splenectomy between July 2013 and April 2017 at Toho University. Mycophenolate mofetil (MMF) was initiated on day - 10. Rituximab (100 mg) was administered twice. Basiliximab and triple maintenance immunosuppression (calcineurin inhibitor, MMF, and steroids) were administered. Protocol biopsy was performed at 3 months and 1 year after transplantation. We retrospectively compared the clinical outcomes between these recipients and 37 children (mean age 9.0, range 2.6-18.9, 15 female) who underwent ABO-compatible (ABOc) LDKT during the same period.

RESULTS

The mean follow-up periods of ABOi and ABOc groups were 31.9 ± 13.5 and 28.8 ± 14.4 months, respectively. In the ABOi group, no clinical acute rejection (AR) was noted and subclinical AR was observed in four patients without evidence of acute antibody-mediated rejection. In the ABOc group, clinical and subclinical AR developed in 3 and 10 patients, respectively. No significant difference was identified for the mean eGFR between the ABOi and ABOc groups (98.3 ± 48.8 vs. 86.9 ± 39.4, P = 0.452 at 3 months; 78.2 ± 21.2 vs. 79.7 ± 21.3, at 1 year, P = 0.830). Death-censored graft survival at follow-up was 100% in the ABOi group and 94.6% in the ABOc group. Patient survival during the follow-up period in both the groups was 100%. Late-onset neutropenia (LON) requiring granulocyte colony-stimulating factor occurred more frequently in the ABOi group than in the ABOc group (4 vs. 0 patients) (P < 0.001).

CONCLUSIONS

Pre- and post-transplantation antibody removal is not a prerequisite for successful pediatric ABOi LDKT, at least in patients with a low anti-A/B IgG antibody titer. However, LON caused by rituximab should be monitored.

Efficacy of 2 Doses of Rituximab on B-Cell and Antidonor Antibody and Outcomes of ABO-Incompatible Living-Donor Pediatric Kidney Transplant

OBJECTIVES

Rituximab treatment strategies vary in ABOincompatible pediatric kidney transplant recipients. Here, we present the efficacy of 2 doses of rituximab and subsequent outcomes in ABO-incompatible pediatric kidney transplant patients.

MATERIALS AND METHODS

Our study of ABO-incompatible pediatric kidney transplant recipients included 21 who were pretreated with desensitization that included 2 doses of 100 mg rituximab (rituximab group) at 10 and 1 day pretransplant and 14 who received splenectomy without rituximab (splenectomy group). Both groups received immunosuppression. Basiliximab was administered during transplant and 4 days posttransplant. Double-filtration plasmapheresis and/or plasma exchange procedures were performed pretransplant in those with higher antidonor antibody titers. CD19-positive and CD20-positive B cells were measured sequentially in the rituximab group. Maximum titers of antidonor antibody pre- and posttransplant, patient and graft survival, biopsy-proven rejection, and complications/infections were compared between groups.

RESULTS

In the rituximab group, CD19- and CD20-positive B cells were depleted on transplant, persistently depleted at 3 months, and under 5% until 1 year posttransplant. Maximum titers of antidonor antibodies decreased significantly posttranplant in the rituximab (P < .001) but not in the splenectomy group (P = .174), with maximum titers posttransplant significantly lower than shown in the splenectomy group (P < .001). No rituximab patients had clinical rejection, but 5 splenectomy group patients had clinical T-cell-mediated rejection, with 2 also having antibody-mediated rejection. Six in the rituximab group had cytomegalovirus viremia but no cytomegalovirus disease; however, 5 splenectomy group recipients had cytomegalovirus disease and viremia. In the rituximab group, 3 had late-onset neutropenia. One child died of hypertrophic cardio myopathy with a functioning graft; all others survived with no failed grafts. All splenectomy group children survived, although 2 had deteriorated graft function.

CONCLUSIONS

Two doses of rituximab were effective in long-term B-cell depletion to suppress antidonor antibodies. The possibility of late-onset neutropenia must be considered.

State-of-the-art immunosuppression protocols for pediatric renal transplant recipients

Immunosuppressive protocols used in pediatric kidney transplantation have changed substantially within the last decade. Many transplant centers now focus on the use of tacrolimus and mycophenolate mofetil in combination with early steroid withdrawal, frequently combined with antibody induction therapy. However, this approach is mainly based on treatment efficacy and-compared to other immunosuppressive regimens used in this context-leads to higher rates of viral infections in patients. In this review I assess data from prospective, interventional trials of immunosuppressive therapy in pediatric kidney transplantation. However, since there is a paucity of randomized controlled trials, I also describe the results of studies with weaker designs. The advantages and disadvantages of different immunosuppressive strategies are discussed. Within this framework I suggest ideas for individualized immunosuppressive regimens based on different stratificators that could effect a change from a 'one size fits all' to a tailored approach for initial and maintenance immunosuppressive therapy after renal transplantation in the pediatric setting.

Desensitisation strategies in high-risk children before kidney transplantation

BACKGROUND

Transplantation is the preferred modality for renal replacement therapy in children. With increasing rates of re-transplantation within the paediatric population, there are more sensitised children on waiting lists. One issue with developing strategies to treat these children is the number of different definitions of sensitisation. and we would therefore recommend an immunological risk stratification approach.

METHODS

We discuss methods of sensitisation prevention, assessment and management, including paired exchange programmes and desensitisation protocols.

RESULTS

There are limited published evidence-based data for desensitisation in adults and none in children; thus, we present information on the available therapies currently in use.

DISCUSSION

Further research is required to investigate strategies which prevent sensitisation in children, including the healthcare utility of incorporating epitope-based matching into organ allocation algorithms. Controlled studies are also needed to establish the most appropriate desensitisation regimen(s).

Pediatric ABO-incompatible kidney transplantation: Evolving with the advancing apheresis technology: A single-center experience

Recent literature has endorsed favorable outcomes following ABOi kidney transplantation in pediatric population. Nevertheless, reluctance to pursue an ABOi still remains pervasive. This could be ascribed to various legitimate reasons, namely less extensive pediatric ABOi data, technical difficulties encountered during PP, cost restraints, and concerns regarding higher rates of antibody-mediated rejection, infectious complications, and post-transplant lymphoproliferative disorder as compared to adults. However, given the similar excellent outcomes of both ABOi and ABOc kidney transplantation, clinicians should consider this option sooner if a compatible donor or swap is not available. Here, we describe the outcomes of three pediatric ABOi performed at our institute in India (from 2014 till now), wherein distinct apheresis modalities had been employed in each desensitization protocol, and our techniques evolved with advancing science in apheresis. This case series includes India's first published pediatric ABO-incompatible transplant (Case 2) and the youngest child to undergo ABO-incompatible renal transplant in SAARC nations (Case 3).

Pediatric kidney transplantation

Since first performed in 1954, kidney transplantation has evolved as the preferred long-term treatment of children with end stage renal disease (ESRD). The etiology of chronic kidney disease (CKD) and ESRD in children is broad and can be quite complicated, necessitating a multidisciplinary team to adequately care for these patients and their myriad needs. Precise surgical techniques and modern protocols for immunosuppression provide excellent long-term patient and graft survival. This article reviews the many etiologies of renal failure in the pediatric population focusing on those most commonly leading to the need for kidney transplantation. The processes of evaluation, kidney transplantation, short-term and long-term complications, as well as long-term outcomes are also reviewed.

Desensitization protocol enabling pediatric crossmatch-positive renal transplantation: successful HLA-antibody-incompatible renal transplantation of two highly sensitized children

BACKGROUND

Renal transplantation improves quality of life (QoL) and survival in children requiring renal replacement therapy (RRT). Sensitization with development of a broad-spectrum of anti-HLA antibodies as a result of previous transplantation or after receiving blood products is an increasing problem. There are no published reports of desensitization protocols in children allowing renal transplantation from HLA-antibody-incompatible living donors.

METHODS

We adopted our well-established adult desensitization protocol for this purpose and undertook HLA antibody-incompatible living donor renal transplants in two children: a 14-year-old girl and a 13-year-old boy.

RESULTS

After 2 and 1.5 years of follow-up, respectively, both patients have stable renal allograft function despite a rise in donor-specific antibodies in one case.

CONCLUSIONS

HLA-incompatible transplantation should be considered in selected cases for sensitized children.