Current approaches in national kidney paired donation programs

Kidney paired donation in developing countries: A global perspective

Purpose of review

We review the key principles of kidney paired donation (KPD) and discuss the status and unique considerations for KPD in developing countries.

Recent findings

Despite the advantages of KPD programs, they remain rare among developing nations, and the programs that exist have many differences with those of in developed countries. There is a paucity of literature and lack of published data on KPD from most of the developing nations. Expanding KPD programs may require the adoption of features and innovations of successful KPD programs. Cooperation with national and international societies should be encouraged to ensure endorsement and sharing of best practices.

Summary

KPD is in the initial stages or has not yet started in the majority of the emerging nations. But the logistics and strategies required to implement KPD in developing nations differ from other parts of the world. By learning from the KPD experience in developing countries and adapting to their unique needs, it should be possible to expand access to KPD to allow more transplants to happen for patients in need world-wide.

Long-Term Outcomes of Kidney Paired Donation Transplantation: A Single Center Retrospective Cohort Study

BACKGROUND

This study aimed to compare the kidney paired donation (KPD) program recipients with the traditional living donor kidney transplantation (LDKT) recipients regarding patient and graft survival.

METHODS

We retrospectively analyzed 141 recipients of the KPD program and 141 classic LDKT recipients that we matched for age and sex as controls between July 2005 and June 2019. We compared the 2 transplant groups for patient and kidney survival using the Kaplan-Maier test. We also performed Cox Regression analysis to examine factors affecting patient survival, including transplant type.

RESULTS

The average follow-up period was 96.17 ± 44.22 months. Of the 282 patients, 88 died in the follow-up period. There was no statistically significant difference in graft and patient survival between the KPD and LDKT groups. In the Cox regression model, including the transplant type, only the serum creatinine level measured in the first month after discharge was a significant factor in predicting patient survival.

CONCLUSIONS

The findings of this study indicate that the KPD program is an effective and reliable method to increase LDKT. Country-wide multicentric studies should confirm the results of this study. In countries where cadaver transplantation is insufficient, efforts should be made to expand the KPD program.

Cohort profile: The Swiss Transplant Cohort Study (STCS): A nationwide longitudinal cohort study of all solid organ recipients in Switzerland

PURPOSE

The Swiss Transplant Cohort Study (STCS) is a prospective multicentre cohort study which started to actively enrol study participants in May 2008. It takes advantage of combining data from all transplant programmes in one unique system to perform comprehensive nationwide reporting and to promote translational and clinical post-transplant outcome research in the framework of Swiss transplantation medicine.

PARTICIPANTS

Over 5500 solid organ transplant recipients have been enrolled in all six Swiss transplant centres by end of 2019, around three-quarter of them for kidney and liver transplants. Ninety-three per cent of all transplanted recipients have consented to study participation, almost all of them (99%) contributed to bio-sampling. The STCS genomic data set includes around 3000 patients.

FINDINGS TO DATE

Detailed clinical and laboratory data in high granularity as well as patient-reported outcomes from transplant recipients and activities in Switzerland are available in the last decade. Interdisciplinary contributions in diverse fields of transplantation medicine such as infectious diseases, genomics, oncology, immunology and psychosocial science have resulted in approximately 70 scientific papers getting published in peer-review journals so far.

FUTURE PLANS

The STCS will deepen its efforts in personalised medicine and digital epidemiology, and will also focus on allocation research and the use of causal inference methods to make complex matters in transplant medicine more understandable and transparent.

Presence of a survival benefit of HLA-incompatible living donor kidney transplantation compared to waiting or HLA-compatible deceased donor kidney transplantation with a long waiting time

HLA-incompatible living donor kidney transplantation (LDKT) is one of efforts to increase kidney transplantation opportunity for sensitized patients with kidney failure. However, there are conflicting reports for outcomes of HLA-incompatible kidney transplantation compared to patients who wait for HLA-compatible deceased donor kidney transplantation (DDKT) in the United States and United Kingdom. Waiting for an HLA-compatible DDKT is relatively disadvantageous in Korea, because the average waiting time is more than five years. To study this further, we compared outcomes of HLA-incompatible LDKT with those who wait for HLA-compatible DDKT in Korea. One hundred eighty nine patients underwent HLA-incompatible LDKT after desensitization between 2006 and 2018 in two Korean hospitals (42 with a positive complement-dependent cytotoxicity cross-match, 89 with a positive flow cytometric cross-match, and 58 with a positive donor-specific antibody with negative cross-match). The distribution of matched variables was comparable between the HLA-incompatible LDKT group and the matched control groups (waiting-list-only group; and the waiting-list-or-HLA-compatible-DDKT groups; 930 patients each). The HLA-incompatible LDKT group showed a significantly better patient survival rate compared to the waiting-list-only group and the waiting-list-or-HLA-compatible-DDKT groups. Furthermore, the HLA-incompatible LDKT group showed a significant survival benefit as compared with the matched groups at all strength of donor-specific antibodies. Thus, HLA-incompatible LDKT could have a survival benefit as compared with patients who were waitlisted for HLA-compatible DDKT or received HLA-compatible DDKT in Korea. This suggests that HLA-incompatible LDKT as a good option for sensitized patients with kidney failure in countries with prolonged waiting times for DDKT.

Changing patterns of clinical decision making: are falling numbers of antibody incompatible transplants related to the increasing success of the UK Living Kidney Sharing Scheme? A national cohort study

Antibody incompatibility is a barrier to living kidney transplantation; antibody incompatible transplantation (AIT) is an accepted treatment modality, albeit higher risk. This study aims to determine changes to clinical decision making and access to AIT in the UK. An electronic survey was sent to all UK renal transplant centres (n = 24), in 2014, and again in 2018. Questions focused on entry & duration in the UKLKSS for HLA and ABO-incompatible pairs, Can and provision of direct AIT transplantation within those centres. Between 2014 & 2018, the duration recommended for patients in the UKLKSS increased. In 2014, 34.8% of centres reported leaving HLA-i pairs in the UKLKSS indefinitely, or reviewing on a case by case basis, by 2018 this increased to 61%. Centres offering direct HLA-i transplantation reduced from 58% to 37%. For low titre (1:8) ABO-i recipients, 66% of centres recommended at least 9 months (3 matching runs) in the UKLKSS scheme in 2018, compared to 47% in 2014, 50% fewer units consider direct ABO-i transplantation for unsuccessful pairs with high ABO titres (>1:512). Over time, clinicians appear to be facilitating more conservative management of AIT patients, potentially limiting access to living donor transplantation.

Preoperative carfilzomib and lulizumab based desensitization prolongs graft survival in a sensitized non-human primate model

Sensitized patients are difficult to transplant due to pre-formed anti-donor immunity. We have previously reported successful desensitization using carfilzomib and belatacept in a non-human primate (NHP) model. Here we evaluated selective blockade of the co-stimulatory signal (CD28-B7) with Lulizumab, which preserves the co-inhibitory signal (CTLA4-B7). Five maximally MHC-mismatched pairs of NHPs were sensitized to each other with two sequential skin transplants. Individuals from each pair were randomized to either desensitization with once-weekly Carfilzomib (27mg/m² IV) and Lulizumab (12.5mg/kg SC) over four weeks, or no desensitization (Control). NHPs then underwent life-sustaining kidney transplantation from their previous skin donor. Rhesus-specific anti-thymocyte globulin was used as induction therapy and immunosuppression maintained with tacrolimus, mycophenolate, and methylprednisolone. Desensitized subjects demonstrated a significant reduction in donor-specific antibody, follicular helper T cells (CD4⁺PD-1⁺ICOS⁺), and proliferating B cells (CD20⁺Ki67⁺) in the lymph nodes. Interestingly, regulatory T cell (CD4⁺CD25⁺CD127^lo) frequency was maintained after desensitization in addition to increased frequency of naïve CD4 T cells (CCR7⁺CD45RA⁺) and naïve B cells (IgD⁺CD27^-CD20⁺) in circulation. This was associated with significant prolongation in graft survival (MST = 5.8 ± 4.0 vs. 64.8 ± 36.3; p<0.05) and lower antibody-mediated rejection scores compared to control animals. However, all desensitized animals eventually developed AMR and graft failure. Desensitization with CFZ and Lulizumab improves allograft survival in allosensitized NHPs, by transient control of the germinal center and shifting of the immune system to a more naive phenotype. This regimen may translate into clinical practice to improve outcomes of highly sensitized transplant patients.

KPDGUI: An interactive application for optimization and management of a virtual kidney paired donation program

BACKGROUND AND OBJECTIVES

The aim in kidney paired donation (KPD) is typically to maximize the number of transplants achieved through the exchange of donors in a pool comprising incompatible donor-candidate pairs and non-directed (or altruistic) donors. With many possible options in a KPD pool at any given time, the most appropriate set of exchanges cannot be determined by simple inspection. In practice, computer algorithms are used to determine the optimal set of exchanges to pursue. Here, we present our software application, KPDGUI (Kidney Paired Donation Graphical User Interface), for management and optimization of KPD programs.

METHODS

While proprietary software platforms for managing KPD programs exist to provide solutions to the standard KPD problem, our application implements newly investigated optimization criteria that account for uncertainty regarding the viability of selected transplants and arrange for fallback options in cases where potential exchanges cannot proceed, with intuitive resources for visualizing alternative optimization solutions.

RESULTS

We illustrate the advantage of accounting for uncertainty and arranging for fallback options in KPD using our application through a case study involving real data from a paired donation program, comparing solutions produced under different optimization criteria and algorithmic priorities.

CONCLUSIONS

KPDGUI is a flexible and powerful tool for offering decision support to clinicians and researchers on possible KPD transplant options to pursue under different user-specified optimization schemes.

A review of the possibility of adopting financially driven live donor kidney transplantation

Kidney transplantation for end-stage renal disease remains the preferred solution due to its survival advantage, enhanced quality of life and cost-effectiveness. The main obstacle worldwide with this modality of treatment is the scarcity of organs. The demand has always exceeded the supply resulting in different types of donations. Kidney donation includes pure living related donors, deceased donors, living unrelated donors (altruistic), paired kidney donation and more recently compensated kidney donation. Ethical considerations in live donor kidney transplantation have always created a debate especially when rewarding unrelated donors. In this paper, we examine the problems of financially driven kidney transplantation, the ethical legitimacy of this practice, and propose some innovative methods and policies that could be adopted to ensure a better practice with accepted ethical guidelines.

Advanced Donation Programs and Deceased Donor-Initiated Chains-2 Innovations in Kidney Paired Donation

Kidney paired donation (KPD) strategies have facilitated compatible living-donor kidney transplants for end-stage renal disease patients with willing but incompatible living donors. Success has inspired further innovations that expand opportunities for kidney-paired donation. Two such innovations are the advanced donation strategy in which a donor provides a kidney before their recipient is matched, or even in need of, a kidney transplant, and deceased donor initiated chains in which chains are started with deceased donors rather than altruistic living donors. Although these innovations may expand KPD, they raise several ethical issues. Specific concerns raised by advanced donation include the management of uncertainty, the extent of donor and recipient consent, the scope of the obligation that the organization has to the kidney exchange paired recipient, the naming of alternative recipients, and the potential to unfairly advantage the recipient. Use of deceased donors for chain-initiating kidneys raises ethical issues concerning the consent process for each involved party, the prioritization of deceased donor kidneys, the allocation of chain ending kidneys, and the value of a living donor kidney versus a deceased donor kidney. We outline each ethical issue and discuss how it can be conceptualized and managed so that these KPD innovations programs are ultimately successful.

Past, present and future of kidney paired donation transplantation in India

One third of healthy willing living kidney donors are rejected due to ABO blood group incompatibility and donor specific antibody. This increases pre-transplant dialysis duration leading to increased morbidity and mortality on the kidney transplantation waiting list. Over the last decade kidney paired donation is most rapidly increased source of living kidney donors. In a kidney transplantation program dominated by living donor kidney transplantation, kidney paired donation is a legal and valid alternative strategy to increase living donor kidney transplantation. This is more useful in countries with limited resources where ABO incompatible kidney transplantation or desensitization protocol is not feasible because of costs/infectious complications and deceased donor kidney transplantation is in initial stages. The matching allocation, ABO blood type imbalance, reciprocity, simultaneity, geography were the limitation for the expansion of kidney paired donation. Here we describe different successful ways to increase living donor kidney transplantation through kidney paired donation. Compatible pairs, domino chain, combination of kidney paired donation with desensitization or ABO incompatible transplantation, international kidney paired donation, non-simultaneous, extended, altruistic donor chain and list exchange are different ways to expand the donor pool. In absence of national kidney paired donation program, a dedicated kidney paired donation team will increase access to living donor kidney transplantation in individual centres with team work. Use of social networking sites to expand donor pool, HLA based national kidney paired donation program will increase quality and quantity of kidney paired donation transplantation. Transplant centres should remove the barriers to a broader implementation of multicentre, national kidney paired donation program to further optimize potential of kidney paired donation to increase transplantation of O group and sensitized patients. This review assists in the development of similar programs in other developing countries.

Thirty Years of Experience at the First Tunisian Kidney Transplant Center

OBJECTIVES

The aim of this study was to report the results of 30 years of experience at the first kidney transplant center in Tunisia.

MATERIALS AND METHODS

All kidney transplants performed at the center between June 1986 and June 2016 were included. The study period was divided into 3 decades. Recipient and donor data and follow-up information were obtained from a local database and patient medical records. Comparative analyses were performed using the t test for continuous variables and the Χ² test for qualitative variables. Patient and graft survival rates were calculated according to the actuarial method, and comparison of survival curves was performed according to the logrank test.

RESULTS

The mean age of recipients was 32.7 ± 11.5 years (range, 6-65 y) with a gender ratio of 2.2. Duration of prekidney transplant dialysis varied from 2 months to 20 years (median, 27.5 mo); 1.7% of patients underwent transplant preemptively. Kidneys were recovered from deceased donors in 21.2% of cases and from living donors in 78.8%. The proportion of deceased donors dropped from 27.4% during the period 2006-2010 to 12.9% during the period 2011-2015 (P < .04). Patient survival rates at 1, 5, 10, 15, and 20 years were 96%, 89.3%, 79.5%, 71.1%, and 65.4%. Graft survival rates were 95%, 86.5%, 76.2%, 66.3%, and 57.2%. The annual graft loss was 2.9%, with a mortality rate of 2.4% and without significant differences between patients receiving deceased-donor and living-donor organs.

CONCLUSIONS

Kidney transplant activity remains suboptimal in our country. The reduction in deceased-donor organs could be related to the political transformations facing our country with their resulting social and economic consequences. Efforts should be made to increase governmental resources and to improve both public awareness of organ donation and the motivation of transplant teams.

Rethinking the advantage of zero-HLA mismatches in unrelated living donor kidney transplantation: implications on kidney paired donation

The OPTN/UNOS Kidney Paired Donation (KPD) Pilot Program allocates priority to zero-HLA mismatches. However, in unrelated living donor kidney transplants (LDKT)-the same donor source in KPD-no study has shown whether zero-HLA mismatches provide any advantage over >0 HLA mismatches. We hypothesize that zero-HLA mismatches among unrelated LDKT do not benefit graft survival. This retrospective SRTR database study analyzed LDKT recipients from 1987 to 2012. Among unrelated LDKT, subjects with zero-HLA mismatches were compared to a 1:1-5 matched (by donor age ±1 year and year of transplantation) control cohort with >0 HLA mismatches. The primary endpoint was death-censored graft survival. Among 32,654 unrelated LDKT recipients, 83 had zero-HLA mismatches and were matched to 407 controls with >0 HLA mismatches. Kaplan-Meier analyses for death-censored graft and patient survival showed no difference between study and control cohorts. In multivariate marginal Cox models, zero-HLA mismatches saw no benefit with death-censored graft survival (HR = 1.46, 95% CI 0.78-2.73) or patient survival (HR = 1.43, 95% CI 0.68-3.01). Our data suggest that in unrelated LDKT, zero-HLA mismatches may not offer any survival advantage. Therefore, particular study of zero-HLA mismatching is needed to validate its place in the OPTN/UNOS KPD Pilot Program allocation algorithm.

Kidney paired donation: principles, protocols and programs

Due to the ongoing shortage of deceased-donor organs, novel strategies to augment kidney transplantation rates through expanded living donation strategies have become essential. These include desensitization in antibody-incompatible transplants and kidney paired donation (KPD) programs. KPD enables kidney transplant candidates with willing but incompatible living donors to join a registry of other incompatible pairs in order to find potentially compatible transplant solutions. Given the significant immunologic barriers with fewer donor options, single-center or small KPD programs may be less successful in transplanting the more sensitized patients; the optimal solution for the difficult-to-match patient is access to more potential donors and large multicenter or national registries are essential. Multicenter KPD programs have become common in the last decade, and now represent one of the most promising opportunities to improve transplant rates. To maximize donor-recipient matching, and minimize immunologic risk, these multicenter KPD programs use sophisticated algorithms to identify optimal match potential, with simultaneous two-, three- or more complex multiway exchanges. The article focuses on the recent progresses in KPD and it also reviews some of the differences and commonalities across four different national KPD programs.

Increasing access to renal transplantation in India through our single-center kidney paired donation program: a model for the developing world to prevent commercial transplantation

Because access to transplantation with HLA-desensitization protocols and ABO incompatible transplantation is very limited due to high costs and increased risk of infections from more intense immunosuppression, kidney paired donation (KPD) promises hope to a growing number of end-stage renal disease (ESRD) patient in India. We present a government and institutional ethical review board approved study of 56 ESRD patients [25 two-way and 2 three-way pairs] who consented to participate in KPD transplantation at our center in 2013, performed to avoid blood group incompatibility (n = 52) or positive cross-match (n = 4). All patients had anatomic, functional, and immunologically comparable donors. The waiting time in KPD was short as compared to deceased donor transplantation. Laparoscopic donor nephrectomy was performed in 54 donors. Donor relationships were spousal (n = 40), parental (n = 13), others (n = 3), with median HLA match of 1. Graft survival was 97.5%. Three patients died with functioning graft. 16% had biopsy-proven acute rejection. Mean serum creatinine was 1.2 mg/dl at 0.73 ± 0.32 months follow-up. KPD is a viable, legal, and rapidly growing modality for facilitating LDRT for patients who are incompatible with their healthy, willing living donor. To our knowledge, this is the largest single-center report from India.

Molecular deciphering of the ABO system as a basis for novel diagnostics and therapeutics in ABO incompatible transplantation

In recent years ABO incompatible kidney transplantation (KTx) has become a more or less clinical routine procedure with graft and patient survival similar to those of ABO compatible transplants. Antigen-specific immunoadsorption (IA) for anti-A and anti-B antibody removal constitutes in many centers an important part of the treatment protocol. ABO antibody titration by hemagglutination is guiding the treatment; both if the recipient can be transplanted as well as in cases of suspected rejections if antibody removal should be performed. Despite the overall success of ABO incompatible KTx, there is still room for improvements and an extension of the technology to include other solid organs. Based on an increased understanding of the structural complexity and tissue distribution of ABH antigens and the fine epitope specificity of the ABO antibody repertoire, improved IA matrices and ABO antibody diagnostics should be developed. Furthermore, understanding the molecular mechanisms behind accommodation of ABO incompatible renal allografts could make it possible to induce long-term allograft acceptance also in human leukocyte antigen (HLA) sensitized recipients and, perhaps, also make clinical xenotransplantation possible.

Does donor-recipient age difference matter in outcome of kidney transplantation? Implications for kidney paired donation

BACKGROUND

Kidney paired donation (KPD) is a rapidly growing modality for facilitating living donor kidney transplantation (LDKTx) for patients who are incompatible with their healthy, willing and living donor. The impact of donor-recipient age difference on long and short-term graft and patient survivals in LDKTx is still uncertain.

METHODS

A total of 1502 LDKTx recipients who received regular follow-up in our center from 1999 to 2012 were studied. Donor-recipient age difference was divided into subgroups (donor-recipient 0-10, 11-20, 0-20, 21-30, 31-40, and 21-40 years). Outcome measures included death censored graft, patient survival and acute rejection rate.

RESULTS

The 1-, 5-, 10-year patient survival of the donor-recipient age difference ≤20 years group showed no difference compared with the age difference >20 years group (94.5%, 83.2%, 71.9% and 95.2%, 86%, 77.8%, p = 0.053). The 1-, 5-, 10-year graft survival of the donor-recipient age difference ≤20 years group showed no difference compared with the age difference >20 years group (94.6%, 81.6%, 72.1% and 94%, 80%, 72.2%, p = 0.989). The rejection were also similar (17.5% vs. 16.5%, p > 0.05). There was no statistically significant difference in graft survival and acute rejection rate in all subgroups.

CONCLUSIONS

Older donors (usually within families) are not associated with worse outcome is reassuring. KPD should not be prohibited due to high donor-recipient age difference, when size of donor pool is small as in single center KPD program.