Controversies in kidney paired donation

Liver paired exchange: A US single-center experience-Pairs, chains, and use of compatible pairs

In the United States, the discrepancy between organ availability and need has persisted despite changes in allocation, innovations in preservation, and policy initiatives. Living donor liver transplant remains an underutilized means of improving access to timely liver transplantation and decreasing waitlist mortality. Liver paired exchange (LPE) represents an opportunity to overcome living donor liver transplant pair incompatibility due to size, anatomy, or blood type. LPE was adopted as a strategy to augment access to liver transplantation at our institution. Specific educational materials, consent forms, and selection processes were developed to facilitate LPE. From 2019 through October 2023, our center performed 11 LPEs, resulting in 23 living donor liver transplant pairs. The series included several types of LPE: those combining complementary incompatible pairs, the inclusion of compatible pairs to overcome incompatibility, and the use of altruistic nondirected donors to initiate chains. These exchanges facilitated transplantation for 23 recipients, including 1 pediatric patient. LPE improved access to liver transplantation at our institution. The ethical application of LPE includes tailored patient education, assessment and disclosure of exchange balance, mitigation of risk, and maximization of benefit for donors and recipients.

Current protocols and outcomes of ABO-incompatible kidney transplantation

One of the principal obstacles in transplantation from living donors is that approximately 30% are immunologically incompatible because of the presence in the recipient of antibodies directed against the human leukocyte antigen system of the donor or because of the incompatibility of the ABO system. The aim of this review is to describe the more recent data from the literature on the different protocols used and the clinical outcomes of ABO-incompatible kidney transplantation. Two different strategies are used to overcome these barriers: desensitization of the recipient to remove the antibodies and to prevent their rebound after transplantation and the exchange of organs between two or more pairs. The largest part of this review is dedicated to describing the techniques of desensitization. Even if the first reports of successful renal transplantation between ABO-incompatible pairs have been published by 1980, the number of ABO-incompatible transplants increased substantially in this century because of our improved knowledge of the immune system and the availability of new drugs. Rituximab has substantially replaced splenectomy. The technique of apheresis has improved and more recently a tailored desensitization proved to be the more efficient strategy avoiding an excess of immunosuppression with the related side effects. Recent reports document outcomes for such transplantation similar to the outcomes of standard transplantation.

The 6-year clinical outcomes for patients registered in a multiregional United States Kidney Paired Donation program - a retrospective study

We examined what happened during a 6-year period to 1121 end-stage renal disease patients who registered with their willing/incompatible living donors for kidney exchanges with the Alliance for Paired Donation (APD). Of all patients, 65% were transplanted: 37% in kidney paired donation (APD-KPD, APD-other-KPD); 10% with compatible live donors (APD-LD); and 18% with deceased donors (APD-DD). The remaining patients were withdrawn (sick/died/others; 15%), or were still waiting (20%). For those patients with a cPRA 0-94%, 72% received a transplant. In contrast, only 49% of very highly sensitized (VHS; cPRA 95-100%) were transplanted. Of the VHS patients, 50% were transplanted by KPD/APD-LD while 50% benefited through prioritization of deceased donors in the modified kidney allocation system (KAS introduced in 2014). All APD transplanted groups had similar death-censored 4-year graft survivals as their relevant Organ Procurement and Transplantation Network (OPTN) groups. It is noteworthy that VHS graft and patient survival results were comparable to less sensitized and nonsensitized patients. All patients should be encouraged to search for compatible donors through different options. Expanding the donor pool through KPD and the new KAS of the OPTN increases the likelihood of transplantation for VHS patients.

Challenges for the Travelling Donor: Variability Between Donor Workup and Donor Surgery in the Canadian Kidney Paired Exchange Program

BACKGROUND

A primary obstacle to providing renal transplantation is limited access to donated kidneys. The living-donor pool for renal allografts was greatly expanded through implementation of a kidney paired donation program. Whereas some programs ship donor kidneys to the site of renal transplantation, others send the donor to the site of transplantation. Performing the nephrectomy and transplantation at the same location may optimize functional renal outcomes, but preferred surgical approaches may differ between surgical teams performing the donor workup and donor surgery. Our objective was to identify incongruence between the surgery planned by the team that performed the donor's workup, and the surgery that took place at the site of donation.

METHODS

A retrospective chart review was performed between the site of preoperative surgical planning, and the site of surgery for kidney donors in the Canadian kidney paired donation program.

RESULTS

Fifty-one donors were preoperatively prepared in any of six Canadian provinces, and then underwent surgery in a different province. The surgical procedure performed for 31% of the patients' nephrectomies differed from the procedure suggested by the surgical team who conducted the preoperative workup. Half of these differences were between left laparoscopic and left laparoscopic hand-assisted, but the remainder included more substantial changes of sides and/or laparoscopic versus open procedures.

CONCLUSION

Optimal patient care is challenged in a kidney paired donation program that uses the "traveling donor" approach due to differing surgical techniques selected by the surgeon at the site of donor workup and the surgeon at the site of donation.

Six-year outcomes in broadly HLA-sensitized living donor transplant recipients desensitized with intravenous immunoglobulin and rituximab

Desensitization with intravenous immunoglobulin (IVIG) and rituximab can improve transplantation rates in broadly sensitized kidney transplant recipients. However, long-term outcomes are lacking. Here we analyze long-term outcomes in living donor kidney transplant recipients desensitized with this regimen and compare them to low-risk recipients. Living donor kidney transplants that took place between July 2006 and December 2010 were considered retrospectively. The primary end point of the study was death-censored allograft survival at last follow-up. Secondary end points included patient survival, incidence of rejection, glomerular filtration rate (GFR), and proteinuria. There were 66 sensitized and 111 low-risk patients included. Average follow-up was 68 months. There was no difference in long-term patient or graft survival. The rate of rejection was similar in the groups with more early rejection in the sensitized group and more late rejection in the low-risk group. There was more antibody-mediated rejection in the sensitized group. Estimated GFR was similar during the follow-up period. Risk factors for rejection included a positive cross-match (HR: 2.4 CI: 1.35-4.40) and age (HR: 0.97 CI: 0.95-0.99). Desensitization with IVIG and rituximab has good long-term results with graft outcomes similar to non-HLA-sensitized patients despite higher immunologic risk.

Equipoise: ethical, scientific, and clinical trial design considerations for compatible pair participation in kidney exchange programs

Compatible living donor/recipient pair participation (CPP) in kidney exchange (KE) transplantation may substantially increase transplant volumes and significantly mitigate the O blood group donor shortage in KE. Initial ethical analysis did not support CPP for two primary reasons: (1) KE would be "unbalanced," and (2) the possibility of undue influence experienced by the compatible pair living donor. Recent developments with CPP (modeling studies and small clinical experiences), have demonstrated substantial potential for increasing KE volumes. This encouraged us to reconsider initial ethical concerns, with a focus on the potential for a design of a prospective CPP clinical trial. This ethical reconsideration led us to conclude that the concept of unbalanced kidney exchanges (manifested primarily by differential benefit between compatible and incompatible pairs) is no longer as clear cut as originally conceived. In addition, application of two concepts substantially diminishes ethical concerns including: (1) "quasi-compatible" pairs, and (2) a priori definition of mitigating factors. We conclude that genuine uncertainty exists regarding whether kidney exchange is best performed with or without compatible pair participation and that a clinical trial is therefore warranted.

Comparison of kidney paired donation transplantations with living related donor kidney transplantation: implications for national kidney paired donation program

BACKGROUND

Kidney Paired Donation (KPD) is a rapidly growing modality for facilitating living related donor kidney transplantation (LRDKTx) for patients who are incompatible with their healthy, willing, and living donors. Data scarcity on the outcome of KPD versus LRDKTx prompted us to review our experience.

MATERIALS AND METHODS

This was a single-center study of 224 patients on regular follow-up, who underwent LRDRTx from January 2010 to June 2012 at our institute. The aim of this study was to compare short-term graft survival, patient survival and rejection rates of KPD (group 1, n = 34) with those of LRDKTx (group 2, n = 190). All the recipients received triple immunosuppression and thymoglobulin induction in KPD group. Kaplan-Meier curves were used for survival analysis. In group 1, mean recipient age was 35.5 ± 13.2 years, 29 were men and mean donor age was 44.4 ± 8.17 years, 10 were men. In group 2, mean recipient age was 29.1 ± 10 years, 155 were men and mean donor age was 47.5 ± 9.69 years, 74 were men. Mean human leukocyte antigen (HLA) matching in group 1 and 2 was 1 versus 3.2 (p < 0.05).

RESULTS

One- and two-year patient survival showed no significant difference between the two groups (97.1%, 97.1% vs. 96.2%, 94.8%, respectively, p = 0.81). Death-censored graft survival also showed no significant difference between the two groups (97.1%, 97.1%, vs. 97.6%, 97.6%, p = 0.73). Acute rejection incidence was also similar (8.7% vs. 9.9%, p > 0.62).

CONCLUSIONS

Our study showed similar graft survival, patient survival and rejection rates of KPD versus LRDKTx over 2 years post-transplantation, encouraging the use of this approach for national KPD program.

Precision diagnostics in transplantation: from bench to bedside

The Canadian and American Societies of Transplantation held a symposium on February 22, 2012 in Quebec City focused on discovery, validation and translation of new diagnostic tools into clinical transplantation. The symposium focused on antibody testing, transplantation pathology, molecular diagnostics and laboratory support for the incompatible patient. There is an unmet need for more precise diagnostic approaches in transplantation. Significant potential for increasing the diagnostic precision in transplantation was recognized through the integration of conventional histopathology, molecular technologies and sensitive antibody testing into one enhanced diagnostic system.

Outcome of kidney paired donation transplantation to increase donor pool and to prevent commercial transplantation: a single-center experience from a developing country

BACKGROUND

Economic constraints in operating an effective maintenance dialysis program leaves renal transplantation as the only viable option for end-stage renal disease patients in India. Kidney paired donation (KPD) is a rapidly growing modality for facilitating living donor (LD) transplantation for patients who are incompatible with their healthy, willing LD.

MATERIALS AND METHODS

The aim of our study was to report a single-center feasibilities and outcomes of KPD transplantation between 2000 and 2012. We performed KPD transplants in 70 recipients to avoid blood group incompatibility (n = 56) or to avoid a positive crossmatch (n = 14).

RESULTS

Over a mean follow-up of 2.72 ± 2.96 years, one-, five- and ten-year patient survival were 94.6, 81, 81 %, and death-censored graft survival was 96.4, 90.2, 90.2 %, respectively. Ten percent of patients were lost, mainly due to infections (n = 4). There was 14.2 % biopsy-proven acute rejection, and 5.7 % interstitial fibrosis with tubular atrophy eventually leading to graft loss.

CONCLUSION

The incidences of acute rejection, patient/graft survival rates were acceptable in our KPD program and, therefore, we believe it should be encouraged. These findings are valuable for encouraging participation of KPD pairs and transplant centers in national KPD program. It should be promoted in centers with low-deceased donor transplantation. Our study findings are relevant in the context of Indian government amending the Transplantation of Human Organs Act to encourage national KPD program. To our knowledge, it is largest single-center report from India.