Utilization and outcomes of kidney paired donation in the United States. Transplantation. 2008;86:502-510. [PMID: 18724216 DOI: 10.1097/tp.0b013e3181812f85]

Therapeutic apheresis in kidney diseases: an updated review

Besides conventional medical therapies, therapeutic apheresis has become an important adjunctive or alternative therapeutic option to immunosuppressive agents for primary or secondary kidney diseases and kidney transplantation. The available therapeutic apheresis techniques used in kidney diseases, including plasma exchange, double-filtration plasmapheresis, immunoadsorption, and low-density lipoprotein apheresis. Plasma exchange is still the leading extracorporeal therapy. Recently, growing evidence supports the potential benefits of double-filtration plasmapheresis and immunoadsorption for more specific and effective clearance of pathogenic antibodies with fewer side effects. However, more randomized controlled trials are still needed. Low-density lipoprotein apheresis is also an important supplementary therapy used in patients with recurrent focal segmental glomerulosclerosis. This review collects the latest evidence from recent studies, focuses on the specific advantages and disadvantages of these techniques, and compares the discrepancy among them to determine the optimal therapeutic regimens for certain kidney diseases.

Controversies in Living Kidney Donation

The most precious gift that can be given is, arguably, a living organ to a person in need of replacement because of failure of that organ. Kidney transplantation remains the best modality of renal replacement therapy and there is an ever-increasing demand for organ donation. The inability of cadaveric organ donation to meet the needs of the increasing numbers of patients on global waiting lists highlights the important needs for alternate sources for kidneys such as those from living kidney donation. However, living donor kidney transplantation has been a focus of intense debate, with ethical concerns and controversies emanating from operating on an individual who does not need, and is put at a small but quantifiable risk from, the surgical intervention. Furthermore, health care systems across the world also are funded with different levels of national and individual affordability, leading to health inequalities for the sick and risks of exploitation for the poor, especially through commercialization of transplantation. This article highlights some of these contemporary ethical concerns and controversies in living organ donation.

Paired kidney donation: are we going beyond reasonable limits in living-donor transplantation?

The growing demand for transplant kidneys requires strategies to increase organ supply and avoid long waiting periods on the list. The increase in the number of transplants from living donors involves the growth in the use of unrelated donors and paired kidney donation. Most of these transplants are performed in the USA, where they already represent, respectively, 34% and 16% of total transplants from living donors. In Latin America, and especially in Brazil, there is no collective enthusiasm for these modalities, either at the request of transplanters or that of the community, with the region's priority being to increase transplants from deceased donors, which growth can be up to three-fold. Concerning transplants from matched donors, the possible conflicting results between donors can generate public challenges and they risk compromise the concepts of equal opportunities for transplant candidates, with the possibility of generating resistance to organ donation, especially in regions with socioeconomic limitations and disparities in access to qualified health care and education. This donation model involves challenging ethical and logistical issues, which are subject to questionings, starting with an act of exchange between two pairs until reaching embarrassing proposals, which can compromise the altruistic character of organ donation, and thus not be universally incorporated.

Motivations and outcomes of compatible living donor-recipient pairs in paired exchange

Increasing numbers of compatible pairs are choosing to enter paired exchange programs, but motivations, outcomes, and system-level effects of participation are not well described. Using a linkage of the Scientific Registry of Transplant Recipients and National Kidney Registry, we compared outcomes of traditional (originally incompatible) recipients to originally compatible recipients using the Kaplan-Meier method. We identified 154 compatible pairs. Most pairs sought to improve HLA matching. Compared to the original donor, actual donors were younger (39 vs. 50 years, p < .001), less often female (52% vs. 68%, p < .01), higher BMI (27 vs. 25 kg/m², p = .03), less frequently blood type O (36% vs. 80%, p < .001), and had higher eGFR (99 vs. 94 ml/min/1.73 m², p = .02), with a better LKDPI (median 7 vs. 22, p < .001). We observed no differences in graft failure or mortality. Compatible pairs made 280 additional transplants possible, many in highly sensitized recipients with long wait times. Compatible pair recipients derived several benefits from paired exchange, including better donor quality. Living donor pairs should receive counseling regarding all options available, including kidney paired donation. As more compatible pairs choose to enter exchange programs, consideration should be given to optimizing compatible pair and hard-to-transplant recipient outcomes.

How patients choose kidney transplant centers: A qualitative study of patient experiences

Little is known about how patients make the critical decision of choosing a transplant center. In the United States, acceptance criteria, waiting times, and mortality vary significantly by geography and center. We sought to understand patients' experiences and perspectives when selecting transplant centers. We included 82 kidney transplant patients in 20 semi-structured interviews, nine focus groups with local candidates, and three focus groups with national recipients. Sites included two local transplant centers in Minneapolis, Minnesota, and national recipients from across the United States. Transcripts were analyzed by two researchers using a thematic analysis. Several themes emerged related to priorities and barriers when choosing a center. Patients were often unfamiliar with options, even with multiple local centers. Patients described being referred to a specific center by a trusted provider. Patients prioritized perceived reputation, comfort, and convenience. Insurance coverage was both a source of information and a barrier to options. Patients underestimated differences across centers and the effects on being waitlisted and receiving a transplant. Barriers in decision making included an overwhelming scope of information and difficulty locating information relevant to patients with unique medical needs. Informed decisions could be improved by the dissemination of understandable information better tailored to individual patient needs.

Temporal changes in the composition of a large multicenter kidney exchange clearinghouse: Do the hard-to-match accumulate?

One criticism of kidney paired donation (KPD) is that easy-to-match candidates leave the registry quickly, thus concentrating the pool with hard-to-match sensitized and blood type O candidates. We studied candidate/donor pairs who registered with the National Kidney Registry (NKR), the largest US KPD clearinghouse, from January 2012-June 2016. There were no changes in age, gender, BMI, race, ABO blood type, or panel-reactive antibody (PRA) of newly registering candidates over time, with consistent registration of hard-to-match candidates (59% type O and 38% PRA ≥97%). However, there was no accumulation of type O candidates over time, presumably due to increasing numbers of nondirected type O donors. Although there was an initial accumulation of candidates with PRA ≥97% (from 33% of the pool in 2012% to 43% in 2014, P = .03), the proportion decreased to 17% by June 2016 (P < .001). Some of this is explained by an increase in the proportion of candidates with PRA ≥97% who underwent a deceased donor kidney transplantation (DDKT) after the implementation of the Kidney Allocation System (KAS), from 8% of 2012 registrants to 17% of 2015 registrants (P = .02). In this large KPD clearinghouse, increasing participation of nondirected donors and the KAS have lessened the accumulation of hard-to-match candidates, but highly sensitized candidates remain hard-to-match.

Kidney exchange transplantation current status, an update and future perspectives

Kidney exchange transplantation is well established modality to increase living donor kidney transplantation. Reasons for joining kidney exchange programs are ABO blood group incompatibility, immunological incompatibility (positive cross match or donor specific antibody), human leukocyte antigen (HLA) incompatibility (poor HLA matching), chronological incompatibility and financial incompatibility. Kidney exchange transplantation has evolved from the traditional simultaneous anonymous 2-way kidney exchange to more complex ways such as 3-way exchange, 4-way exchange, n-way exchange,compatible pair, non-simultaneous kidney exchange,non-simultaneous extended altruistic donor, never ending altruistic donor, kidney exchange combined with desensitization, kidney exchange combined with ABO incompatible kidney transplantation, acceptable mismatch transplant, use of A2 donor to O patients, living donor-deceased donor list exchange, domino chain, non-anonymous kidney exchange, single center, multicenter, regional, National, International and Global kidney exchange. Here we discuss recent advances in kidney exchanges such as International kidney exchange transplantation in a global environment, three categories of advanced donation program, deceased donors as a source of chain initiating kidneys, donor renege myth or reality, pros and cons of anonymity in developed world and (non-) anonymity in developing world, pros and cons of donor travel vs kidney transport, algorithm for management of incompatible donor-recipient pairs and pros and cons of Global kidney exchange. The participating transplant teams and donor-recipient pairs should make the decision by consensus about kidney donor travel vs kidney transport and anonymity vs non-anonymity in allocation as per local resources and logistics. Future of organ transplantation in resource-limited setting will be liver vs kidney exchange, a legitimate hope or utopia?

Kidney exchange match rates in a large multicenter clearinghouse

Kidney paired donation (KPD) can facilitate living donor transplantation for candidates with an incompatible donor, but requires waiting for a match while experiencing the morbidity of dialysis. The balance between waiting for KPD vs desensitization or deceased donor transplantation relies on the ability to estimate KPD wait times. We studied donor/candidate pairs in the National Kidney Registry (NKR), a large multicenter KPD clearinghouse, between October 2011 and September 2015 using a competing-risk framework. Among 1894 candidates, 52% were male, median age was 50 years, 66% were white, 59% had blood type O, 42% had panel reactive antibody (PRA)>80, and 50% obtained KPD through NKR. Median times to KPD ranged from 2 months for candidates with ABO-A and PRA 0, to over a year for candidates with ABO-O or PRA 98+. Candidates with PRA 80-97 and 98+ were 23% (95% confidence interval , 6%-37%) and 83% (78%-87%) less likely to be matched than PRA 0 candidates. ABO-O candidates were 67% (61%-73%) less likely to be matched than ABO-A candidates. Candidates with ABO-B or ABO-O donors were 31% (10%-56%) and 118% (82%-162%) more likely to match than those with ABO-A donors. Providers should counsel candidates about realistic, individualized expectations for KPD, especially in the context of their alternative treatment options.

Swaps and Chains and Vouchers, Oh My!: Evaluating How Saving More Lives Impacts the Equitable Allocation of Live Donor Kidneys

Live kidney donation involves a delicate balance between saving the most lives possible and maintaining a transplant system that is fair to the many thousands of patients on the transplant waiting list. Federal law and regulations require that kidney allocation be equitable, but the pressure to save patients subject to ever-lengthening waiting times for a transplant has been swinging the balance toward optimizing utility at the expense of justice. This article traces the progression of innovations created to make optimum use of a patient's own live donors. It starts with the simplest - direct donation by family members - and ends with voucher donations, a very recent and unique innovation because the donor can donate 20 or more years before the intended recipient is expected to need a kidney. In return for the donation, the intended recipient receives a voucher that can be redeemed for a live kidney when it is needed. Other innovations that are discussed include kidney exchanges and list paired donation, which are used to facilitate donor swaps when donor/recipient pairs have incompatible blood types. The discussion of each new innovation shows how the equity issues build on each other and how, with each new innovation, it becomes progressively harder to find an acceptable balance between utility and justice. The article culminates with an analysis of two recent allocation methods that have the potential to save many additional lives, but also affirmatively harm some patients on the deceased donor waiting list by increasing their waiting time for a life-saving kidney. The article concludes that saving additional lives does not justify harming patients on the waiting list unless that harm can be minimized. It also proposes solutions to minimize the harm so these new innovations can equitably perform their intended function of stimulating additional transplants and extending the lives of many transplant patients.

Seventy-seven kidney paired donation transplantations at a single transplant centre in India led to an increase in living donor kidney transplantations in 2015

Background

To ascertain the validity of kidney paired donations (KPDs) as an alternative strategy for increasing living donor kidney transplantations (LDKTs) in an LDKT-dominated transplant programme since directed kidney transplantation, ABO-incompatible or crossmatch-positive pairs are not feasible due to costs and infectious complications.

Methods

This was a prospective single-centre study of 77 KPD transplantations (25 two-way, 7 three-way and 1 six-way exchange) from 1 January 2015 to 1 January 2016 of 158 registered donor recipient pairs. During this period, a total of 380 kidney transplantations [71 deceased donor kidney transplantations (DDKTs), 309 LDKTs] were performed. The reasons for opting for KPD were ABO incompatibility (n = 45), sensitization (n = 26) and better matching (n = 6).

Results

KPD matching was facilitated in 62% (n = 98) of transplants. In all, 48.7% (n = 77) of the transplants were completed in 2015, whereas 13.3% (n = 21) of the matched patients were to undergo transplant surgery in early 2016 after getting legal permission. The waiting time for KPD was shorter compared with DDKT. The death-censored graft survival and patient survival were 98.7% (n = 76) and 93.5% (n = 72), respectively. In all, 14.2% (n = 11) of patients had acute rejection. Match rates among sensitized (n = 60) and O group patients (n = 62) were 58.3% (n = 35) and 41.9% (n = 26), respectively. Of these, 43.3% (n = 26) and 29% (n = 18) of transplants were completed and 15% (n = 9) and 12.9% (n = 8), respectively, are waiting for legal permission.

Conclusions

LDKT increased by 25% in 1 year in our single-centre KPD programme. Our key to success was the formation of a KPD registry, awareness and active counselling programs and developing a dedicated team.

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.

Impact of single centre kidney paired donation transplantation to increase donor pool in India: a cohort study

In a living donor kidney transplantation (LDKT) dominated transplant programme, kidney paired donation (KPD) may be a cost-effective and valid alternative strategy to increase LDKT in countries with limited resources where deceased donation kidney transplantation (DDKT) is in the initial stages. Here, we report our experience of 300 single-centre KPD transplantations to increase LDKT in India. Between January 2000 and July 2016, 3616 LDKT and 561 DDKT were performed at our transplantation centre, 300 (8.3%) using KPD. The reasons for joining KPD among transplanted patients were ABO incompatibility (n = 222), positive cross-match (n = 59) and better matching (n = 19). A total of 124 two-way (n = 248), 14 three-way (n = 42), one four-way (n = 4) and one six-way exchange (n = 6) yielded 300 KPD transplants. Death-censored graft and patient survival were 96% (n = 288) and 83.3% (n = 250), respectively. The mean serum creatinine was 1.3 mg/dl at a follow-up of 3 ± 3 years. We credit the success of our KPD programme to maintaining a registry of incompatible pairs, counselling on KPD, a high-volume LDKT programme and teamwork. KPD is legal, cost effective and rapidly growing for facilitating LDKT with incompatible donors. This study provides large-scale evidence for the expansion of single-centre LDKT via KPD when national programmes do not exist.

International kidney paired donation transplantations to increase kidney transplant of O group and highly sensitized patient: First report from India

AIM

To report the first international living related two way kidney paired donation (KPD) transplantation from India which occurred on 17^th February 2015 after legal permission from authorization committee.

METHODS

Donor recipient pairs were from Portugal and India who were highly sensitized and ABO incompatible with their spouse respectively. The two donor recipient pairs had negative lymphocyte cross-matching, flow cross-match and donor specific antibody in two way kidney exchange with the intended KPD donor. Local KPD options were fully explored for Indian patient prior to embarking on international KPD.

RESULTS

Both pairs underwent simultaneous uneventful kidney transplant surgeries and creatinine was 1 mg/dL on tacrolimus based immunosuppression at 11 mo follow up. The uniqueness of these transplantations was that they are first international KPD transplantations in our center.

CONCLUSION

International KPD will increases quality and quantity of living donor kidney transplantation. This could be an important step to solving the kidney shortage with additional benefit of reduced costs, improved quality and increased access for difficult to match incompatible pairs like O blood group patient with non-O donor and sensitized patient. To the best of our knowledge this is first international KPD transplantation from India.

Preconditioning Therapy in ABO-Incompatible Living Kidney Transplantation: A Systematic Review and Meta-Analysis

BACKGROUND

ABO-incompatible (ABOi) kidney transplantation is now an established form of renal replacement therapy, but the efficacy and safety of the different types of preconditioning therapies are unclear. We aimed to synthesize the totality of the published evidence about the effects of any form of preconditioning therapies in living donor ABOi kidney transplantation on graft and patient outcomes.

METHODS

We searched MEDLINE, Embase, and Clinicaltrial.gov databases (inception through June 2015) to identify all studies that described the outcomes of adult living donor ABOi kidney transplantations using any form of preconditioning therapies. Two independent reviewers identified studies, extracted data, and assessed the risk of bias. Data were summarized using the random effects model, and heterogeneity was explored using subgroup analyses. We assessed confidence in the evidence using the Grading of Recommendations Assessment, Development, and Evaluation framework.

RESULTS

Eighty-three studies (54 case reports and case series, 25 cohort, 2 case-control, and 2 registry studies) involving 4810 ABOi transplant recipients were identified. Overall, confidence in the available evidence was low. During a mean follow-up time of 28 (standard deviation [SD], 26.6) months, the overall graft survival for recipients who received immunoadsorption or apheresis was 94.1% (95% confidence interval [95%CI], 88.2%-97.1%) and 88.0% (95% CI, 82.6%-91.8%), respectively. For those who received rituximab or underwent splenectomy, the overall graft survival was 94.5% (95% CI, 91.6%-96.5%) and 79.7% (95% CI, 72.9%-85.1%), respectively. Data on other longer-term outcomes, including malignancy, were sparse.

CONCLUSIONS

Rituximab or immunoadsorption appeared to be promising preconditioning strategies before ABOi kidney transplantation. However, the overall quality of evidence and the confidence in the observed treatment effects are low. The increased use of ABOi kidney transplantation needs to be matched with randomized trials of different types, dosing, and frequency of preconditioning therapies so that this scarce resource can be used most effectively and efficiently.

BARTERING FOR A COMPATIBLE KIDNEY USING YOUR INCOMPATIBLE, LIVE KIDNEY DONOR: LEGAL AND ETHICAL ISSUES RELATED TO KIDNEY CHAINS

Kidney chains are a recent and novel method of increasing the number of available kidneys for transplantation and have the potential to save thousands of lives. However, because they are novel, kidney chains do not fit neatly within existing legal and ethicalframeworks, raising potential barriers to their full implementation. Kidney chains are an extension of paired kidney donation, which began in the United States in 2000. Paired kidney donations allow kidney patients with willing, but incompatible, donors to swap donors to increase the number of donor/recipient pairs and consequently, the number of transplants. More recently, transplant centers have been using non-simultaneous, extended, altruistic donor ("NEAD") kidney chains--which consist of a sequence of donations by incompatible donors--to further expand the number of donations. This Article fully explains paired kidney donation and kidney chains and focuses on whether NEAD chains are more coercive than traditional kidney donation to a family member or close friend and whether NEAD chains violate the National Organ Transplant Act's prohibition on the transfer of organs for valuable consideration.

Historical Matching Strategies in Kidney Paired Donation: The 7-Year Evolution of a Web-Based Virtual Matching System

Failure to convert computer-identified possible kidney paired donation (KPD) exchanges into transplants has prohibited KPD from reaching its full potential. This study analyzes the progress of exchanges in moving from "offers" to completed transplants. Offers were divided into individual segments called 1-way transplants in order to calculate success rates. From 2007 to 2014, the Alliance for Paired Donation performed 243 transplants, 31 in collaboration with other KPD registries and 194 independently. Sixty-one of 194 independent transplants (31.4%) occurred via cycles, while the remaining 133 (68.6%) resulted from nonsimultaneous extended altruistic donor (NEAD) chains. Thirteen of 35 (37.1%) NEAD chains with at least three NEAD segments accounted for 68% of chain transplants (8.6 tx/chain). The "offer" and 1-way success rates were 21.9 and 15.5%, respectively. Three reasons for failure were found that could be prospectively prevented by changes in protocol or software: positive laboratory crossmatch (28%), transplant center declined donor (17%) and pair transplanted outside APD (14%). Performing a root cause analysis on failures in moving from offer to transplant has allowed the APD to improve protocols and software. These changes have improved the success rate and the number of transplants performed per year.

Difference in outcomes after antibody-mediated rejection between abo-incompatible and positive cross-match transplantations

Graft survival seems to be worse in positive cross-match (HLAi) than in ABO-incompatible (ABOi) transplantation. However, it is not entirely clear why these differences exist. Sixty-nine ABOi, 27 HLAi and 10 combined ABOi+HLAi patients were included in this retrospective study, to determine whether the frequency, severity and the outcome of active antibody-mediated rejection (AMR) were different. Five-year death-censored graft survival was better in ABOi than in HLAi and ABOi+HLAi patients (99%, 69% and 64%, respectively, P = 0.0002). Features of AMR were found in 38%, 95% and 100% of ABOi, HLAi and ABOi+HLAi patients that had a biopsy, respectively (P = 0.0001 and P = 0.001). After active AMR, a declining eGFR and graft loss were observed more frequently in HLAi and HLAi+ABOi than in ABOi patients. The poorer prognosis after AMR in HLAi and ABOi+HLAi transplantations was not explained by a higher severity of histological lesions or by a less aggressive treatment. In conclusion, ABOi transplantation offers better results than HLAi transplantation, partly because AMR occurs less frequently but also because outcome after AMR is distinctly better. HLAi and combined ABOi+HLAi transplantations appear to have the same outcome, suggesting there is no synergistic effect between anti-A/B and anti-HLA antibodies.

Assessing the efficacy of kidney paired donation--performance of an integrated three-site program

BACKGROUND

Kidney paired donation (KPD) has emerged as a viable option for renal transplant candidates with incompatible living donors. The aim of this study was to assess the "performance" of a three-site KPD program that allowed screening of multiple donors per recipient.

METHODS

We reviewed retrospectively the activity of our KPD program involving three centers under the same institutional umbrella. The primary goal was to achieve a transplant that was both ABO compatible and had a negative or low-positive flow cytometric crossmatch (+XM).

RESULTS

During the 40-month study period, 114 kidney transplant candidates were enrolled-57% resulting from a +XM and 39% resulting from ABO incompatible (ABOi) donors. Important outcomes were as follows: (1) 81 (71%) candidates received a transplant and 33 (29%) were still waiting; (2) 368 donors were evaluated, including 10 nondirected donors; (3) 82% (37/45) of ABOi candidates underwent transplantation; (4) 56% (36/65) of +XM candidates underwent transplantation (however, all but four of these had a cPRA less than 95%); (5) at the end of the study period, 97% (28/29) of +XM candidates still waiting had a cPRA greater than 95%.

CONCLUSIONS

These data suggest evaluating large numbers of donors increases the chances of KPD. Patients with a cPRA greater than 95% are unlikely to receive a negative or low-positive +XM, suggesting the need for desensitization protocols in KPD.

[Kidney paired donation. Combination with extracorporeal desensitization]

BACKGROUND

Live kidney donation represents the gold standard for renal replacement therapy. Due to ABO and HLA incompatibility between donor and recipient pairs, one third of possible transplantations cannot be performed. Kidney exchange programs in combination with extracorporeal desensitization have been introduced to enable successful kidney transplantation in such circumstances.

OBJECTIVE

This review discusses the current indications, methods, ethical problems and results within such programs.

MATERIALS AND METHODS

Relevant Medline articles were analyzed and personal experiences of the authors are included in this article.

RESULTS

Kidney exchange programs in combination with extracorporeal desensitization enable successful transplantation for most patients.

DISCUSSION

The best combinations of existing strategies have to be defined and newly arisen ethical questions have to be answered.

Center-defined unacceptable HLA antigens facilitate transplants for sensitized patients in a multi-center kidney exchange program

Multi-center kidney paired donation (KPD) is an exciting new transplant option that has not yet approached its full potential. One barrier to progress is accurate virtual crossmatching for KPD waitlists with many highly sensitized patients. Virtual crossmatch results from a large multi-center consortium, the National Kidney Registry (NKR), were analyzed to determine the effectiveness of flexible center-specific criteria for virtual crossmatching. Approximately two-thirds of the patients on the NKR waitlist are highly sensitized (>80% CPRA). These patients have antibodies against HLA-A (63%), HLA-B (66%), HLA-C (41%), HLA-DRB1 (60%), HLA-DRB3/4/5 (18-22%), HLA-DQB1 (54%) and HLA-DPB1 (26%). With donors typed for these loci before activation, 91% of virtual crossmatches accurately predicted an acceptable cell-based donor crossmatch. Failed virtual crossmatches were attributed to equivocal virtual crossmatches (46%), changes in HLA antibodies (21%), antibodies against HLA-DQA (6%), transcription errors (6%), suspected non-HLA antibodies (5%), allele-specific antibodies (1%) and unknown causes (15%). Some failed crossmatches could be prevented by modifiable factors such as more frequent assessment of HLA antibodies, DQA1 typing of donors and auditing data entry. Importantly, when transplant centers have flexibility to define crossmatch criteria, it is currently feasible to use virtual crossmatching for highly sensitized patients to reliably predict acceptable cell-based crossmatches.

Foundations and principles of the Canadian living donor paired exchange program

Purpose of review

Kidney paired donation (KPD) remains an important strategy to facilitate transplantation in patients who have a healthy and willing donor, but are unable to proceed with directed donation due to either ABO incompatibility or a positive cross-match against their intended donor.

Sources of information

Personal knowledge, The Canadian Blood Services Database for Living Donor Exchange, published reports and personal communications.

Findings

The national Living Donor Paired Exchange Programme (LDPE) in Canada was established in 2009. 235 transplants were completed of which 190 were registered recipients and 45 were from the deceased donor (DD) wait list. At 1 year, patient survival was 100%, graft survival 98%, with a biopsy proven acute rejection rate of 8%. The mean serum creatinine (Cr) at the end of one year was 109 mmol/l. Donor survival is 100%. Key to success are national standards for antibody testing and cross-matching, and for evaluating donors and recipients, as well infrastructure (software and personnel) to run the program. The structure of the Canadian program is compared with that of other programs in the United Kingdom, Australia, the Netherlands, and the United States.

Limitations

This review does not include information on travel distances and difficulties, or patient satisfaction.

Implications

National collaboration and acceptance of common standards is possible and leads to substantial benefits, especially for those patients who are hardest to match.

What was known before: Kidney paired donation is considered ethically acceptable. National and regional programs have been created in a number of countries.

What this paper adds: Key to the success of the Canadian national program are acceptance of standardized procedures and national and provincial support and oversight.

Issues in solid-organ transplantation in children: translational research from bench to bedside

In this review, we identify important challenges facing physicians responsible for renal and cardiac transplantation in children based on a review of the contemporary medical literature. Regarding pediatric renal transplantation, we discuss the challenge of antibody-mediated rejection, focusing on both acute and chronic antibody-mediated rejection. We review new diagnostic approaches to antibody-mediated rejection, such as panel-reactive antibodies, donor-specific cross-matching, antibody assays, risk assessment and diagnosis of antibody-mediated rejection, the pathology of antibody-mediated rejection, the issue of ABO incompatibility in renal transplantation, new therapies for antibody-mediated rejection, inhibiting of residual antibodies, the suppression or depletion of B-cells, genetic approaches to treating acute antibody-mediated rejection, and identifying future translational research directions in kidney transplantation in children. Regarding pediatric cardiac transplantation, we discuss the mechanisms of cardiac transplant rejection, including the role of endomyocardial biopsy in detecting graft rejection and the role of biomarkers in detecting cardiac graft rejection, including biomarkers of inflammation, cardiomyocyte injury, or stress. We review cardiac allograft vasculopathy. We also address the role of genetic analyses, including genome-wide association studies, gene expression profiling using entities such as AlloMap®, and adenosine triphosphate release as a measure of immune function using the Cylex® ImmuKnow™ cell function assay. Finally, we identify future translational research directions in heart transplantation in children.

Optimal testing of the live organ donor for blood-borne viral pathogens: the report of a consensus conference

In 2011, live donor transmission events involving Human Immunodeficiency Virus (HIV) and Hepatitis C virus (HCV) prompted consideration of changing the process of live donor testing and evaluation in the United States. Following CDC recommendations for screening all live donors with nucleic acid testing for HIV, HCV and Hepatitis B (HBV), a consensus conference was convened to evaluate this recommendation. Workgroups focused on determining whether there was an evidence based rationale for identifying live donors at increased risk for HIV, HBV and HCV, testing options and timing for diagnosing these infections in potential donors and consent issues specific to potential increased risk donor utilization. Strategies for donor assessment were proposed. Based on review of the limited available evidence as well as guidance documents and policies currently in place in the United States and other countries, the conference participants recommended that HIV, HBV and HCV NAT should not be required for live donor evaluation; the optimal timing of live donor testing for these blood borne pathogens has not been determined.

Histocompatibility considerations for kidney paired donor exchange programs

PURPOSE OF REVIEW

To highlight the role of histocompatibility testing in kidney paired donor (KPD) exchange programs as well as the new technological advances that may have an effect on KPD.

RECENT FINDINGS

Technological advances in human leukocyte antigen (HLA) antibody identification using the Luminex single-antigen bead multiplexing platform have facilitated virtual cross-matching and the ability to accurately match donor/recipient pairs through KPD. A knowledge of the limitations of this assay is the key to proper interpretation of the data and maximization of this new technology. Novel assays such as C1q and Ig subclass identification may be useful in further determining which HLA antibodies are clinically relevant.

SUMMARY

KPD is an established method for increasing access to transplantation for patients with incompatible live donors. Advances in histocompatibility testing have played a role in the success of KPD.

Persufflation (gaseous oxygen perfusion) as a method of heart preservation

Persufflation (PSF; gaseous oxygen perfusion) is an organ preservation technique with a potential for use in donor heart preservation. Improved heart preservation with PSF may improve outcomes by maintaining cardiac tissue quality in the setting of longer cold ischemia times and possibly increasing the number of donor hearts available for allotransplant. Published data suggests that PSF is able to extend the cold storage times for porcine hearts up to 14 hours without compromising viability and function, and has been shown to resuscitate porcine hearts following donation after cardiac death. This review summarizes key published work on heart PSF, including prospective implications and future directions for PSF in heart transplantation. We emphasize the potential impact of extending preservation times and expanding donor selection criteria in heart allotransplant. Additionally, the key issues that need to be addressed before PSF were to become a widely utilized preservation strategy prior to clinical heart transplantation are summarized and discussed.

Dynamic challenges inhibiting optimal adoption of kidney paired donation: findings of a consensus conference

While kidney paired donation (KPD) enables the utilization of living donor kidneys from healthy and willing donors incompatible with their intended recipients, the strategy poses complex challenges that have limited its adoption in United States and Canada. A consensus conference was convened March 29-30, 2012 to address the dynamic challenges and complexities of KPD that inhibit optimal implementation. Stakeholders considered donor evaluation and care, histocompatibility testing, allocation algorithms, financing, geographic challenges and implementation strategies with the goal to safely maximize KPD at every transplant center. Best practices, knowledge gaps and research goals were identified and summarized in this document.

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.

Paired kidney donation: outcomes, limitations, and future perspectives

It has been calculated that approximately one-third of willing, otherwise appropriate donor-recipient pairs are biologically incompatible due to blood group differences or positive crossmatches therefore cannot proceed to living donor transplantation. Paired kidney donation (KPD) may overcome this problem. Several types of KPD are in practice today and is a good alternative for incompatible donor-recipient couples. According to the existing data, KPD can increase the number of kidney transplants form living donors while providing excellent clinical results. This is also a cost-effective treatment as compared with dialysis and desensitization protocols. However, there are several barriers and limitations of this program. This article analyzed the advantages as well as the drawbacks and shortcomings of KPD programs.

Chain transplantation: initial experience of a large multicenter program

We report the results of a large series of chain transplantations that were facilitated by a multicenter US database in which 57 centers pooled incompatible donor/recipient pairs. Chains, initiated by nondirected donors, were identified using a computer algorithm incorporating virtual cross-matches and potential to extend chains. The first 54 chains facilitated 272 kidney transplants (mean chain length = 5.0). Seven chains ended because potential donors became unavailable to donate after their recipient received a kidney; however, every recipient whose intended donor donated was transplanted. The remaining 47 chains were eventually closed by having the last donor donate to the waiting list. Of the 272 chain recipients 46% were ethnic minorities and 63% of grafts were shipped from other centers. The number of blood type O-patients receiving a transplant (n = 90) was greater than the number of blood type O-non-directed donors (n = 32) initiating chains. We have 1-year follow up on the first 100 transplants. The mean 1-year creatinine of the first 100 transplants from this series was 1.3 mg/dL. Chain transplantation enables many recipients with immunologically incompatible donors to be transplanted with high quality grafts.

Single-center kidney paired donation: the Methodist San Antonio experience

Many potential kidney transplant recipients are unable to receive a live donor transplant due to crossmatch or blood type incompatibility. Kidney paired donation increases access to live donor transplantation but has been significantly underutilized. We established a kidney paired donation program including consented incompatible donor/recipient pairs as well as compatible pairs with older non-human leukocyte antigen identical donors. Over a 3-year period, a total of 134 paired donor transplants were performed, including 117 incompatible pairs and 17 compatible pairs. All transplants were done with negative flow cytometry crossmatches and five were done with desensitization combined with paired donation. Kidney paired donation transplants included two-way and three-way exchanges as well as three chains initiated by nondirected donors. Of the sensitized recipients transplanted by paired donation, 44% had calculated panel reactive antibody levels greater than 80%. Transplantation of females and prior transplant recipients was significantly higher with paired donation. Only three episodes of rejection occurred and no transplants were lost due to rejection. These data highlight the potential of kidney paired donation and suggest that all transplant centers should be actively engaged in paired donation to increase access to live donor transplantation.

Racial differences in outcomes of the evaluation of potential live kidney donors: a retrospective cohort study

BACKGROUND

In the USA, the lower rate of live donor kidney transplant among Black transplant candidates may stem from lower rates of donation among potential live donors who are Black. We determined whether outcomes of the evaluation of potential live kidney donors varied according to the potential donors' demographic characteristics.

METHODS

We performed a single-center, retrospective observational cohort study of 1,179 potential live kidney donors, who came forward between 2000 and 2007. Potential donors' intended recipients were first-time transplant recipients who were evaluated between 2000 and 2005.

RESULTS

There were 268 (22.7%) potential live kidney donors who were Black, of whom 93.7% were recruited by Black transplant candidates. Donor outcomes included actual donation (38.3%), exclusion due to blood group or crossmatch incompatibility (20.4%), exclusion due to medical contraindication to donation (13.7%), and lack of further donor interest (11.2%). Black (vs. non-Black) potential donors were less likely to actually donate (27.2 vs. 41.6%, p < 0.001). Black potential donors were more likely to stop pursuing live donation (p = 0.047) or be excluded from donation for medical reasons (p = 0.008) or blood group or crossmatch incompatibility (p = 0.01). These racial differences persisted in a multivariable multinomial logistic regression model of factors associated with outcomes of the donor evaluation.

CONCLUSIONS

Potential live kidney donors who are Black are less likely to actually donate. Future studies should determine whether paired exchange and desensitization programs decrease these racial differences and why Black potential donors appear more likely to stop pursuing live donation.

Outcomes of ABO-incompatible kidney transplantation in the United States

BACKGROUND

ABO incompatible (ABOi) kidney transplantation is an important modality to facilitate living donor transplant for incompatible pairs. To date, reports of the outcomes from this practice in the United States have been limited to single-center studies.

METHODS

Using the Scientific Registry of Transplant Recipients, we identified 738 patients who underwent live-donor ABOi kidney transplantation between January 1, 1995, and March 31, 2010. These were compared with matched controls that underwent ABO compatible live-donor kidney transplantation. Subgroup analyses among ABOi recipients were performed according to donor blood type, recipient blood type, and transplant center ABOi volume.

RESULTS

When compared with ABO compatible-matched controls, long-term patient survival of ABOi recipients was not significantly different between the cohorts (P=0.2). However, graft loss was significantly higher, particularly in the first 14 days posttransplant (subhazard ratio, 2.34; 95% confidence interval, 1.43-3.84; P=0.001), with little to no difference beyond day 14 (subhazard ratio, 1.28; 95% confidence interval, 0.99-1.54; P=0.058). In subgroup analyses among ABOi recipients, no differences in survival were seen by donor blood type, recipient blood type, or transplant center ABOi volume.

CONCLUSIONS

These results support the use and dissemination of ABOi transplantation when a compatible live donor is not available, but caution that the highest period of risk is immediately posttransplant.

Willingness of the United States general public to participate in kidney paired donation

BACKGROUND

Availability of kidney paired donation (KPD) is increasing in the United States, and a national system through UNOS is forthcoming. However, little is known about attitudes toward KPD among the general public, from which donors (particularly non-directed) are drawn.

METHODS

In a national study, we assessed the public's attitudes regarding participation in KPD.

RESULTS

Among 845 randomly selected participants, 85.2% of respondents were either "extremely willing" or "very willing" to participate in KPD. Experiences with the medical or organ transplant systems, such as undergoing surgery, having a primary medical provider, a living will, a friend who donated or received an organ, and considering donation after death, were associated with increased willingness. However, increased age, male sex, African American race, Hispanic ethnicity, distrust of the medical system, and not understanding organ allocation were associated with less willingness.

CONCLUSIONS

We identify strong support for KPD but some important potential barriers to participation which should be considered as KPD programs are implemented.

The role of the altruistic unbalanced chain in exchange living donor renal transplantation: single-center experience

BACKGROUND

The exchange donor program in renal transplantation is an efficient solution for recipients with a blood type or crossmatch-incompatible donor. However, this program has some difficulties to define unacceptable human leukocyte antigen matches, deteriorating clinical potential recipient condition, and withdrawal of donor consent. We analyzed the outcomes of exchange donor renal transplantation through the altruistic unbalanced chain.

METHODS

Among 152 cases of exchange donor renal transplantation from 1991 to 2010 in our hospital, we performed 58 procedures through altruistic unbalanced chains. We compared their outcomes with the direct and balanced chain group. We analyzed retrospectively whether this program expanded the donor pool, seeking better immunologic, size, and age matching.

RESULTS

The graft survival and acute rejection rates did not differ significantly in the two groups. Of 152 cases, 58 (38.2%) renal transplantations were performed through an unbalanced chain. Seventeen waiting list recipients were transplanted through an altruistic unbalanced chain. In blood type O recipients (n = 32), the causes of registration in the exchange program were ABO incompatibility (93.3%), and positive crossmatch (6.7%). Nine altruistic blood type O donors and 9 (28.1%) type O recipients underwent transplantations through this chain.

CONCLUSIONS

We suggest the altruistic unbalanced chain may expand the donor pool with advantages for difficult-to-match pairs. The disadvantages of type O recipients may be overcome through the use of an unbalanced chain. The altruistic unbalanced exchange transplantation program can help easy-to-match subjects, shortening the waiting periods.

Consideration of donor age and human leukocyte antigen matching in the setting of multiple potential living kidney donors

BACKGROUND

Defining living donor (LD)-related risk factors affecting kidney transplant outcome will allow better donor selection and more educated informed consent when there is more than one potential donor. We studied risk factors in a large cohort at a single institution.

METHODS

We reviewed 1632 recipients who underwent LD kidney transplantation at the University of Minnesota between January 1, 1990, and October 1, 2009. Using Cox regression, we studied the effect of donor and recipient risk factors on patient and graft survival. We specifically examined the effect of donor age and human leukocyte antigen (HLA) matching because these are variables that may help clinical decision making when multiple potential donors exist.

RESULTS

Mean donor age was 40.6 years for all transplants; 180 (11%) donors were 55 years or older, and 24 (1.5%) donors were older than 65 years. Mean number of HLA mismatches (per transplant) was 2.9 (29.2% of recipients had one to two HLA mismatches, 39.8% had three to four HLA mismatches, and 25% had five to six HLA mismatches). Donor age more than 65 years, five to six HLA mismatches, delayed graft function, and acute rejection were independent predictors of decreased patient and graft survival. When controlling for recipient age, donor age more than 65 years remained a risk factor for worse outcome.

CONCLUSIONS

Our data suggest that advanced donor age (>65 years) and degree of HLA mismatch (≥5) are independent donor-related risk factors associated with worse outcome. When multiple potential LDs exist, it may be ideal to attempt to use a donor younger than 65 years and with less than five HLA mismatches.

Paired kidney donor exchanges and antibody reduction therapy: novel methods to ameliorate disparate access to living donor kidney transplantation in ethnic minorities

BACKGROUND

Currently ethnic minority patients comprise 60% of patients listed for kidney transplantation in the US; however, they receive only 55% of deceased donor renal transplants and 25% of living donor renal transplants. Ethnic disparities in access to kidney transplantation result in increased morbidity and mortality for minority patients with end-stage renal disease. Because these patients remain dialysis dependent for longer durations, they are more prone to the development of HLA antibodies that further delay the possibility of receiving a successful kidney transplant.

STUDY DESIGN

Two to 4 pretransplant and post-transplant plasma exchanges and i.v. immunoglobulin were used to lower donor-specific antibody levels to less than 1:16 dilution; cell lytic therapy was used additionally in some cases. Match pairing by virtual cross-matching was performed to identify the maximal exchange benefit. Sixty candidates for renal transplantation were placed into 4 paired kidney exchanges and/or underwent antibody reduction therapy.

RESULTS

Sixty living donor renal transplants were performed by paired exchange pools and/or antibody reduction therapy in recipients whose original intended donors had ABO or HLA incompatibilities or both (24 desensitization and 36 paired kidney exchanges). Successful transplants were performed in 38 ethnic minorities, of which 33 were African American. Twenty-two recipients were white. Graft and patient survival was 100% at 6 months; graft function (mean serum creatinine 1.4 g/dL) and acute rejection rates (20%) have been comparable to traditional live donor kidney transplantation.

CONCLUSIONS

Paired kidney donor exchange pools with antibody reduction therapy can allow successful transplant in difficult to match recipients. This approach can address kidney transplant disparities.

Challenges in organ transplantation

Organ transplantation has progressed tremendously with improvements in surgical methods, organ preservation, and pharmaco-immunologic therapies and has become a critical pathway in the management of severe organ failure worldwide. The major sources of organs are deceased donors after brain death; however, a substantial number of organs come from live donations, and a significant number can also be obtained from non-heart-beating donors. Yet, despite progress in medical, pharmacologic, and surgical techniques, the shortage of organs is a worldwide problem that needs to be addressed internationally at the highest possible levels. This particular field involves medical ethics, religion, and society behavior and beliefs. Some of the critical ethical issues that require aggressive interference are organ trafficking, payments for organs, and the delicate balance in live donations between the benefit to the recipient and the possible harm to the donor and others. A major issue in organ transplantation is the definition of death and particularly brain death. Another major critical factor is the internal tendency of a specific society to donate organs. In the review below, we will discuss the various challenges that face organ donation worldwide, and particularly in Israel, and some proposed mechanisms to overcome this difficulty.

Transporting live donor kidneys for kidney paired donation: initial national results

Optimizing the possibilities for kidney-paired donation (KPD) requires the participation of donor-recipient pairs from wide geographic regions. Initially it was envisaged that donors would travel to the recipient center; however, to minimize barriers to participation and simplify logistics, recent trends have involved transporting the kidneys rather than the donors. The goal of this study was to review outcomes of this practice. KPD programs throughout the United States were directly queried about all transplants involving live donor kidney transport. Early graft function was assessed by urine output in the first 8 h, postoperative serum creatinine trend, and incidence of delayed graft function. Between April 27, 2007 and April 29, 2010, 56 live donor kidneys were transported among 30 transplant centers. Median CIT was 7.2 h (IQR 5.5-9.7, range 2.5-14.5). Early urine output was robust (>100 cc/h) in all but four patients. Creatinine nadir was <2.0 mg/dL in all (including the four with lower urine output) but one patient, occurring at a median of 3 days (IQR 2-5, range 1-49). No patients experienced delayed graft function as defined by the need for dialysis in the first week. Current evidence suggests that live donor kidney transport is safe and feasible.

Who should travel in kidney exchange programs: the donor, or the organ?

In 2009 the Canadian Blood services launched the Living Donor Paired Exchange Registry. This program circumvents the obstacle presented by blood-group or immunologic incompatibility between a living potential donor and his or her intended recipient. At the beginning, only 3 provinces joined the program, but as of October 2010 all Canadian provinces are participants. Up to now, participating donors have travelled to recipients’ transplant centres. We might question whether, in a country such as Canada, the donor or the organ should travel. In this article, we review the arguments for donor travel and the arguments for shipping the kidney.

Living donor exchange programs: theory and practice

BACKGROUND

The crisis in organ availability has triggered innovative approaches to meet a rapidly expanding worldwide demand for donor kidneys. HLA and ABO incompatibility represents one of the most significant barriers to optimizing the utilization of living donors. Kidney paired donation (KPD) allows patients with incompatible live donors to receive compatible or better-matched organs by exchanging donors.

SOURCES OF DATA

The data presented in this review have been published and represent the most up-to-date sources of the theory and practice of KPD.

AREAS OF AGREEMENT

There is wide agreement that in most cases the best transplant solution for a patient with an incompatible donor is to receive a compatible organ in a KPD.

AREAS OF CONTROVERSY

There has been disagreement about the capacity of KPD to solve the incompatibility problem. However, it is now clear that not all phenotypes will benefit from KPD.

GROWING POINTS

Combining KPD with desensitization greatly expands the boundaries of each of these modalities.