Highly Sensitized Patients Are Well Served by Receiving a Compatible Organ Offer Based on Acceptable Mismatches

Desensitization of Highly Immunized Kidney Transplant Recipients Awaiting Transplantation-Polish Single-Center Experience

INTRODUCTION

The increasing number of highly immunized patients waiting for kidney transplantation is a significant problem in Europe as the proportion of such patients has doubled in the last decade. Transplantation in this group is enabled by desensitization methods, i.e., intravenous pharmacotherapy with human immunoglobulin (IVIG), anti-CD20 monoclonal antibody (rituximab), and plasma exchange. The objective was to evaluate the efficacy and safety of this protocol.

MATERIAL AND METHODS

The inclusion criteria: presence of established anti-HLA antibodies with complement-binding capacity, i.e., anti-HLAC1q+ (>MFI 15,000 for the most common antigens), no renal transplantation within 1 year after activation on the waiting list. Thirteen patients were selected for the procedure. IVIG was administered twice (2 g/kg-maximum 140 g/dose). Between IVIG doses, patients received rituximab (375 mg/m2). Anti-HLA was tested after 1 and 2 months after completion of the procedure.

RESULTS

All patients have completed the protocol. No significant changes after desensitization in the amount/profile of alloantibodies were observed. However, with negative vCM for HLA-A/B/DR (no DSA against the reported donor) and negative CM-CDC, according to the allocation system, patients were given priority on the recipient list. Seven out of 13 patients received a transplant within 12 months after treatment (mean 11.5 weeks). Renal graft function was good (mean creatinine level after 1 month: 1.5 mg/dL). No incidents of acute rejection were reported. The most common complications were infections (especially pneumonia).

CONCLUSION

The desensitization protocol (IVIG + rituximab) allows highly immunized patients to undergo organ transplantation. In short-term analysis, no acute rejection was observed, graft function was satisfactory. Desensitization was associated with an increased risk of infection.

Isatuximab Monotherapy for Desensitization in Highly Sensitized Patients Awaiting Kidney Transplant

SIGNIFICANCE STATEMENT

There is no standardized desensitization regimen for kidney transplant candidates. CD38, expressed by plasma cells, could be targeted for desensitization to deplete plasma cells producing alloantibodies and donor-specific antibodies. Few studies and case reports are available regarding the use of CD38 antibodies for desensitization in patients awaiting kidney transplant. This study shows that isatuximab, a CD38-targeting therapy, was well tolerated in kidney transplant candidates, with a durable decrease in anti-HLA antibodies and partial desensitization activity. The short treatment period and long follow-up of this study allowed for the understanding of the mechanism and timing for any antibody rebound. Isatuximab could be further investigated as an option for adjunct therapy to existing desensitization for patients on the kidney transplant waitlist.

BACKGROUND

Patients with calculated panel reactive antibody (cPRA) ≥80.00%, particularly those with cPRA ≥99.90%, are considered highly sensitized and underserved by the Kidney Allocation System. Desensitization removes circulating reactive antibodies and/or suppresses antibody production to increase the chances of a negative crossmatch. CD38 is expressed highly on plasma cells, thus is a potential target for desensitization.

METHODS

This was an open-label single-arm phase 1/2 study investigating the safety, pharmacokinetics, and preliminary efficacy of isatuximab in patients awaiting kidney transplantation. There were two cohorts, cohorts A and B, which enrolled cPRA ≥99.90% and 80.00% to <99.90%, respectively.

RESULTS

Twenty-three patients (12 cohort A, 11 cohort B) received isatuximab 10 mg/kg weekly for 4 weeks then every 2 weeks for 8 weeks. Isatuximab was well tolerated with pharmacokinetic and pharmacodynamic profiles that indicated similar exposure to multiple myeloma trials. It resulted in decreases in CD38 + plasmablasts, plasma cells, and NK cells and significant reductions in HLA-specific IgG-producing memory B cells. Overall response rate, on the basis of a predefined composite desensitization end point, was 83.3% and 81.8% in cohorts A and B. Most responders had decreases in anti-HLA antibodies that were maintained for 26 weeks after the last dose. Overall, cPRA values were minimally affected, however, with only 9/23 patients (39%) having cPRA decreases to target levels. By study cutoff (median follow-up of 68 weeks), six patients received transplant offers, of which four were accepted.

CONCLUSIONS

In this open-label trial, isatuximab was well tolerated and resulted in a durable decrease in anti-HLA antibodies with partial desensitization activity.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04294459 .

Improving the Access of Highly Sensitized Patients to Kidney Transplantation From Deceased Donors: The Spanish PATHI Program With Allocation Based on the Virtual Crossmatch

BACKGROUND

In 2015, the Spanish National Transplant Organization developed a prioritization system (Program for Access to Transplantation for Highly Sensitized Patients [PATHI]) to increase transplant options for patients with calculated panel-reactive antibodies (cPRAs) ≥98%, based on virtual crossmatch. We describe the experience with the implementation of PATHI and assess its efficacy.

METHODS

PATHI registry was used to collect characteristics of donors and patients between June 15, 2015, and March 1, 2018. One-year graft and patient survival and acute rejection were also measured. A Cox model was used to identify factors related to patient death and graft loss and logistical regression for those associated with rejection.

RESULTS

One thousand eighty-nine patients were included, and 272 (25%) were transplanted. Transplant rate by cPRA was 54.9%, 40.5%, and 12.8% in patients with cPRA98%, cPRA99%, and cPRA100%, respectively. One-year patient survival was 92.5%. Recipient age ≥60, time under dialysis >7 y, and delayed graft function were mortality risk factors. One-year graft survival was 88.7%. The factor related to graft loss was delayed graft function. The rejection rate was 22%. Factors related to rejection were sex, older recipients, and posttransplant donor-specific antibodies.

CONCLUSIONS

A prioritization approach increases transplant options for highly sensitized patients with appropriate short-term postransplant outcomes. Along with other programs, PATHI may inspire other countries to adopt strategies to meet transplant needs of these patients.

Old for young kidney transplantation: a responsible option for our patients to reduce waiting time?

PURPOSE

The Eurotransplant Senior program allocating grafts from donors ≥ 65 years to recipients aged ≥ 65 years has proven good results within the last 20 years. However, "old" grafts are also allocated to younger recipients < 65 years, and this outcome of "old for young" kidney transplantations (KT) still lacks detailed investigations.

METHODS

All "old for young" KT performed at four tertiary referral centers were retrospectively compared including a recent follow-up, stratifying for "old for young" (donor ≥ 65 years to recipient < 65 years) vs. "very old for young" KT (donor ≥ 70 years to recipient < 65 years).

RESULTS

Overall, 99 patients were included with 56 (56.6%) "old for young" and 43 (43.4%) "very old for young" KT. The median waiting time did not differ (60.7 vs. 45.8 months, respectively) at comparable living donation rates (57.1% vs. 44.2%) as well as intra- and postoperative results. At a median follow-up of 44 months (range 1; 133), the 3-year graft survival of 91% vs. 87% did not significantly vary. In subgroup analyses assessing living donation or donation after brain death (DBD) KT only, the graft survival was significantly longer for "old for young" KT within the living donation subgroup. In multivariate Cox regression analyses, the presence of panel-reactive antibodies was the only significant impact factor on graft survival (HR 8.32, p = 0.001).

CONCLUSION

This analysis clearly demonstrates the effectiveness of the "old for young" approach, enabling favorable perioperative results as well as comparable data of graft- and overall survival, while reducing waiting time for eligible patients.

Imlifidase Desensitization in HLA-incompatible Kidney Transplantation: Finding the Sweet Spot

Imlifidase, derived from a Streptococcus pyogenes enzyme, cleaves the entire immunoglobulin G pool within hours after administration in fully cleaved antigen-binding and crystallizable fragments. These cleaved fragments can no longer exert their antibody-dependent cytotoxic functions, thereby creating a window to permit HLA-incompatible kidney transplantation. Imlifidase is labeled, in Europe only, for deceased donor kidney transplantation in highly sensitized patients, whose chances for an HLA-compatible transplant are negligible. This review discusses outcomes of preclinical and clinical studies on imlifidase and describes the phase III desensitization trials that are currently enrolling patients. A comparison is made with other desensitization methods. The review discusses the immunological work-up of imlifidase candidates and especially the "delisting strategy" of antigens that shift from unacceptable to acceptable with imlifidase desensitization. Other considerations for clinical implementation, such as adaptation of induction protocols, are also discussed. Imlifidase cleaves most of the currently used induction agents except for horse antithymocyte globulin, and rebound of donor-specific antibodies should be managed. Another consideration is the timing and interpretation of (virtual) crossmatches when bringing this novel desensitization agent into the clinic.

Chimeric HLA antibody receptor T cells to target HLA-specific B cells in solid organ transplantation

HLA-sensitized patients on the transplant waiting list harbor antibodies and memory B cells directed against allogeneic HLA molecules, which decreases the chance to receive a compatible donor organ. Current desensitization strategies non-specifically target circulating antibodies and B cells, warranting the development of therapies that specifically affect HLA-directed humoral immune responses. We developed Chimeric HLA Antibody Receptor (CHAR) constructs comprising the extracellular part of HLA-A2 or HLA-A3 coupled to CD28-CD3ζ domains. CHAR-transduced cells expressing reporter constructs encoding T-cell activation markers, and CHAR-transduced CD8+ T cells from healthy donors were stimulated with HLA-specific monoclonal antibody-coated microbeads, and HLA-specific B cell hybridomas. CHAR T cell activation was measured by upregulation of T cell activation markers and IFNγ secretion, whereas CHAR T cell killing of B cell hybridomas was assessed in chromium release assays and by IgG ELISpot. HLA-A2- and HLA-A3-CHAR expressing cells were specifically activated by HLA-A2- and HLA-A3-specific monoclonal antibodies, either soluble or coated on microbeads, as shown by CHAR-induced transcription factors. HLA-A2 and HLA-A3 CHAR T cells efficiently produced IFNγ with exquisite specificity and were capable of specifically lysing hybridoma cells expressing HLA-A2- or HLA-A3-specific B-cell receptors, respectively. Finally, we mutated the α3 domain of the CHAR molecules to minimize any alloreactive T-cell reactivity against CHAR T cells, while retaining CHAR activity. These data show proof of principle for CHAR T cells to serve as precision immunotherapy to specifically desensitize (highly) sensitized solid organ transplant candidates and to treat antibody-mediated rejection after solid organ transplantation.

Immunized Patients Face Reduced Access to Transplantation in the Eurotransplant Kidney Allocation System

BACKGROUND

The presence of donor-specific HLA antibodies before transplantation is associated with poor transplantation outcomes. Unacceptable antigens can be assigned for Eurotransplant kidney transplant candidates to prevent kidney offers against which the candidate has developed clinically relevant HLA antibodies. This retrospective cohort study aimed to assess to what degree unacceptable antigens affect access to transplantation in the Eurotransplant Kidney Allocation System (ETKAS).

METHODS

Candidates who underwent kidney-only transplantation between 2016 and 2020 were included (n = 19 240). Cox regression was used to quantify the relationship between the relative transplantation rate and virtual panel-reactive antibodies (vPRAs), which is the percentage of the donor pool with unacceptable antigens. Models used accrued dialysis time as the timescale; were stratified by country and blood group of patient and were adjusted for nontransplantable status, patient age, sex, history of kidney transplantations, and prevalence of 0 HLA-DR-mismatched donors.

RESULTS

Transplantation rates were 23% lower for vPRA 0.1% to 50%, 51% lower for vPRA 75% to 85%, and decreased rapidly for vPRA of >85%. Prior studies showed significantly lower ETKAS transplantation rates only for highly sensitized patients (vPRA of >85%). The inverse relationship between transplantation rate and vPRA is independent of Eurotransplant country, listing time, and 0 HLA-DR-mismatched donor availability. Results were similar when quantifying the relationship between vPRA and attainment of a sufficiently high rank for an ETKAS offer, suggesting lower transplantation rates for immunized patients are due to current ETKAS allocation.

CONCLUSIONS

Immunized patients face lower transplantation rates across Eurotransplant. The current ETKAS allocation mechanism inadequately compensates immunized patients for reduced access to transplantation.

Sex and Gender Disparities in Living Kidney Donation: A Scoping Review

Background

Women are more likely than men to be living kidney donors. We summarized the evidence concerning the reasons behind sex and gender disparities in living kidney donation (LKD).

Methods

A scoping review of quantitative and qualitative evidence on reasons for sex and gender disparities in LKD was conducted from inception to March 2023.

Results

Of 1123 studies screened, 45 were eligible for inclusion. Most studies were from North America, Europe, and Central Asia (n = 33, 73%). A predominance of women as living donors (55%-65%) was observed in 15 out of 18 (83%) studies. Reasons for sex and gender disparities in LKD included socioeconomic, biological, and cognitive or emotional factors. A gendered division of roles within the families was observed in most studies, with men being the primary income earner and women being the main caregiver. Fear of loss of income was a barrier to male donation. Human leukocyte antigen sensitization through pregnancy in female recipients precluded male partner donation, whereas female donation was supported by altruism and a positive attitude toward LKD.

Conclusions

Sex imbalance in LKD is prevalent, with a predominance of women as living donors. Such disparities are driven by societal and cultural perceptions of gender roles, pregnancy-induced sensitization, and attitudes toward donation and at least some of these factors are modifiable. Donor compensation to support predonation assessments and income loss, implementation of innovative desensitization treatments, promotion of paired kidney exchange program, and targeted educational initiatives to promote equitable living donation may help to close the gender gap in LKD.

Imlifidase for Kidney Transplantation of Highly Sensitized Patients With a Positive Crossmatch: The French Consensus Guidelines

Imlifidase recently received early access authorization for highly sensitized adult kidney transplant candidates with a positive crossmatch against an ABO-compatible deceased donor. These French consensus guidelines have been generated by an expert working group, in order to homogenize patient selection, associated treatments and follow-up. This initiative is part of an international effort to analyze properly the benefits and tolerance of this new costly treatment in real-life. Eligible patients must meet the following screening criteria: cPRA ≥ 98%, ≤ 65-year of age, ≥ 3 years on the waiting list, and a low risk of biopsy-related complications. The final decision to use Imlifidase will be based on the two following criteria. First, the results of a virtual crossmatch on recent serum, which shall show a MFI for the immunodominant donor-specific antibodies (DSA) > 6,000 but the value of which does not exceed 5,000 after 1:10 dilution. Second, the post-Imlifidase complement-dependent cytotoxicity crossmatch must be negative. Patients treated with Imlifidase will receive an immunosuppressive regimen based on steroids, rATG, high dose IVIg, rituximab, tacrolimus and mycophenolic acid. Frequent post-transplant testing for DSA and systematic surveillance kidney biopsies are highly recommended to monitor post-transplant DSA rebound and subclinical rejection.

Increasing Kidney-Exchange Options Within the Existing Living Donor Pool With CIAT: A Pilot Implementation Study

Computerized integration of alternative transplantation programs (CIAT) is a kidney-exchange program that allows AB0- and/or HLA-incompatible allocation to difficult-to-match patients, thereby increasing their chances. Altruistic donors make this available for waiting list patients as well. Strict criteria were defined for selected highly-immunized (sHI) and long waiting (LW) candidates. For LW patients AB0i allocation was allowed. sHI patients were given priority and AB0i and/or CDC cross-match negative HLAi allocations were allowed. A local pilot was established between 2017 and 2022. CIAT results were assessed against all other transplant programs available. In the period studied there were 131 incompatible couples; CIAT transplanted the highest number of couples (35%), compared to the other programs. There were 55 sHI patients; CIAT transplanted as many sHI patients as the Acceptable Mismatch program (18%); Other programs contributed less. There were 69 LW patients; 53% received deceased donor transplantations, 20% were transplanted via CIAT. In total, 72 CIAT transplants were performed: 66 compatible, 5 AB0i and 1 both AB0i and HLAi. CIAT increased opportunities for difficult-to-match patients, not by increasing pool size, but through prioritization and allowing AB0i and "low risk" HLAi allocation. CIAT is a powerful addition to the limited number of programs available for difficult-to-match patients.

Imlifidase therapy: exploring its clinical uses

INTRODUCTION

Imlifidase, the IgG-degrading enzyme derived from Streptococcus pyogenes, can cleave all four human IgG subclasses with precise specificity. All IgG molecules can be inactivated for ~1-to-2 weeks, until new IgG synthesis is detected.

AREAS COVERED

Imlifidase was first studied for the desensitization of highly HLA-sensitized patients to enable kidney transplantation. It is currently being evaluated for kidney transplant recipients who have antibody-mediated rejection (AMR), those with acute kidney injury in the setting of anti-glomerular basement membrane disease, and those with Guillain-Barré syndrome. In 2020, imlifidase received conditional approval from the European Medicines Agency for use to desensitize deceased-donor kidney transplant recipients with a positive crossmatch. Literature search through PubMed revealed that so far, 39 crossmatched-positive patients, i.e. in the presence of donor-specific alloantibodies (DSA) on the transplantation day, have received imlifidase prior to kidney transplantation in four single-arm, open-label, phase II studies. Results at 3-year follow-up are good, i.e. allograft survival is 84%, despite 38% of patients presenting with acute AMR. Mean estimated glomerular filtration rate at 3 years was 55 mL/min/1.73 m².

EXPERT OPINION

The major hurdle now is how to prevent/avoid DSA rebound within days 5-15 post-transplantation. Thus, imlifidase represents a major breakthrough for highly HLA-sensitized kidney transplant candidates, particularly those that have calculated panel-reactive alloantibodies of ≥90%.

Impact of Sensitization on Waiting Time Prior to Kidney Transplantation in Germany

BACKGROUND

Assignment of unacceptable HLA mismatches (UAMs) prevents transplantation of incompatible grafts but potentially prolongs waiting time. Whether this is true in the Eurotransplant Kidney Allocation System (ETKAS) and the Eurotransplant Senior Program in Germany is highly debated and relevant for UAM policies.

METHODS

Donor pool restriction due to UAM was expressed as percent virtual panel-reactive antibodies (vPRAs). Kaplan-Meier estimates and multivariable Cox regression models were used to analyze the impact of vPRA levels on waiting time and transplant probability during a period of 2 y in all patients eligible for a kidney graft unter standard circumstances in Germany on February 1, 2019 (n = 6533). Utility of the mismatch probability score to compensate for sensitization in ETKAS was also investigated.

RESULTS

In ETKAS, donor pool restriction resulted in significant prolongation of waiting time and reduction in transplant probability only in patients with vPRA levels above 85%. This was most evident in patients with vPRA levels above 95%, whereas patients in the acceptable mismatch program had significantly shorter waiting times and higher chances for transplantation than nonsensitized patients. In the Eurotransplant Senior Program, vPRA levels above 50% resulted in significantly longer waiting times and markedly reduced the chance for transplantation. Compensation for sensitization by the mismatch probability score was insufficient.

CONCLUSIONS

Donor pool restriction had no significant impact on waiting time in most sensitized patients. However, despite the existence of the acceptable mismatch program, the majority of highly sensitized patients is currently disadvantaged and would benefit from better compensation mechanisms.

Scandiatransplant acceptable mismatch program-10 years with an effective strategy for transplanting highly sensitized patients

In March 2009, the Scandiatransplant acceptable mismatch program (STAMP) was introduced as a strategy toward improving kidney allocation to highly sensitized patients. Patients with a transplantability score ≤ 2% are potential candidates for the program. Samples are analyzed and acceptable antigens (HLA-A, B, C, DRB1, DRB3/4/5, DQB1, DQA1, DPB1, DPA1) are defined by the local tissue typing laboratory and finally evaluated by a steering committee. In the matching algorithm, patients have the highest priority when the donor's antigens are all among the recipient's own or acceptable HLA antigens. In the period from 2009 to 2020, we have transplanted 278 highly sensitized kidney patients through the program. The graft survival of the STAMP patients was compared with 9002 deceased donor kidney-transplanted patients, transplanted in the same time period. The 10-year graft survival was 73.4% (95% CI: 60.3-90.0) for STAMP and 82.9% (95% CI: 81.6-84.3) for the reference group. (p = .2). In conclusion, the 10-year allograft survival demonstrates that the STAMP allocation algorithm is immunological safe. The program is continuously monitored and evaluated, and the introduction of matching for all HLA loci is a huge improvement to the program and demonstrate technical adaptability as well as clinical flexibility in a de-centralized organization.

Strategies to Overcome HLA Sensitization and Improve Access to Retransplantation after Kidney Graft Loss

An increasing number of patients waitlisted for kidney transplantation have a previously failed graft. Retransplantation provides a significant improvement in morbidity, mortality, and quality of life when compared to dialysis. However, HLA sensitization is a major barrier to kidney retransplantation and the majority of the highly sensitized patients are waiting for a subsequent kidney transplant. A multidisciplinary team that includes immunogeneticists, transplant nephrologists and surgeons, and adequate allocation policies is fundamental to increase access to a kidney retransplant. A review of Pubmed, ScienceDirect, and the Cochrane Library was performed on the challenges of kidney retransplantation after graft loss, focusing on the HLA barrier and new strategies to overcome sensitization. Conclusion: Technical advances in immunogenetics, new desensitization protocols, and complex allocation programs have emerged in recent years to provide a new hope to kidney recipients with a previously failed graft.

An overview of red blood cell and platelet alloimmunisation in transfusion

Post-transfusion alloimmunisation is the main complication of all those observed after one or more transfusion episodes. Alloimmunisation is observed after the transfusion of red blood cell concentrates but also of platelet concentrates. Besides alloimmunisation due to antigens carried almost exclusively by red blood cells such as those of the Rhesus-Kell system, alloimmunisation often raises against HLA antigens; the main responsibility for that, apart from platelet transfusions, lies with residual leukocytes in the products transfused, hence the central importance of effective leukoreduction right from the blood product preparation stage. Alloimmunization is not restricted to transfusion, but it is also observed during pregnancies, carrying out microtransfusions of blood from the fetus immunizing the mother through the placenta (in a retrograde way). Preexisting maternal-fetal immunization can complicate a transfusion program and intensify the creation of alloantibodies in several blood and tissue group systems. The occurrence of autoantibodies, created by several pathogenic reasons, can also interfere with the propensity of certain recipients of blood components to produce alloantibodies. The genetic condition of individuals is in fact strongly linked to the ability or not to recognize antigenic variants foreign to their own biological program and mount an alloimmune response. Some hemoglobin diseases, in carriers of which transfusions can be iterative and lifelong, are complicated by frequent alloimmunizations and amplification of the complications of these alloimmunizations, imposing even stricter transfusion rules. This review details the mechanisms favoring the occurrence of alloimmunization and the immunological principles for the production of molecular and cellular tools for alloimmunization. It concludes with the main preventive measures available to limit the occurrence of these frequent complications of varying severity but sometimes severe.

The EHA Research Roadmap: Transfusion Medicine

In 2016, the European Hematology Association (EHA) published the EHA Roadmap for European Hematology Research¹ aiming to highlight achievements in the diagnostics and treatment of blood disorders, and to better inform European policy makers and other stakeholders about the urgent clinical and scientific needs and priorities in the field of hematology. Each section was coordinated by 1–2 section editors who were leading international experts in the field. In the 5 years that have followed, advances in the field of hematology have been plentiful. As such, EHA is pleased to present an updated Research Roadmap, now including eleven sections, each of which will be published separately. The updated EHA Research Roadmap identifies the most urgent priorities in hematology research and clinical science, therefore supporting a more informed, focused, and ideally a more funded future for European hematology research. The 11 EHA Research Roadmap sections include Normal Hematopoiesis; Malignant Lymphoid Diseases; Malignant Myeloid Diseases; Anemias and Related Diseases; Platelet Disorders; Blood Coagulation and Hemostatic Disorders; Transfusion Medicine; Infections in Hematology; Hematopoietic Stem Cell Transplantation; CAR-T and Other Cell-based Immune Therapies; and Gene Therapy.

Determination of unacceptable HLA antigen mismatches in kidney transplant recipients

With the introduction of the virtual allocation crossmatch in the Eurotransplant (ET) region in 2023, the determination of unacceptable antigen mismatches (UAM) in kidney transplant recipients is of utmost importance for histocompatibility laboratories and transplant centers. Therefore, a joined working group of members from the German Society for Immunogenetics (Deutsche Gesellschaft für Immungenetik, DGI) and the German Transplantation Society (Deutsche Transplantationsgesellschaft, DTG) revised and updated the previous recommendations from 2015 in light of recently published evidence. Like in the previous version, a wide range of topics is covered from technical issues to clinical risk factors. This review summarizes the evidence about the prognostic value of contemporary methods for HLA antibody detection and identification, as well as the impact of UAM on waiting time, on which these recommendations are based. As no clear criteria could be determined to differentiate potentially harmful from harmless HLA antibodies, the general recommendation is to assign all HLA against which plausible antibodies are found as UAM. There is, however, a need for individualized solutions for highly immunized patients. These revised recommendations provide a list of aspects that need to be considered when assigning UAM to enable a fair and comprehensible procedure and to harmonize risk stratification prior to kidney transplantation between transplant centers. This article is protected by copyright. All rights reserved.

Increasing transplantability in Brazil: time to discuss Kidney Paired Donation

Introduction:

Kidney transplantation (KT) is the best treatment for chronic kidney disease. In Brazil, there are currently more than 26 thousand patients on the waitlist. Kidney Paired Donation (KPD) offers an incompatible donor-recipient pair the possibility to exchange with another pair in the same situation, it is a strategy to raise the number of KT.

Discussion:

KPD ceased being merely an idea over 20 years ago. It currently accounts for 16.2% of living donors KT (LDKT) in the USA and 8% in Europe. The results are similar to other LDKT. It is a promising alternative especially for highly sensitized recipients, who tend to accumulate on the waitlist. KPD is not limited to developed countries, as excellent results were already published in India in 2014. In Guatemala, the first LDKT through KPD was performed in 2011. However, the practice remains limited to isolated cases in Latin America.

Conclusion:

KPD programs with different dimensions, acceptance rules and allocation criteria are being developed and expanded worldwide to meet the demands of patients. The rise in transplantability brought about by KPD mostly meets the needs of highly sensitized patients. The Brazilian transplant program is mature enough to accept the challenge of starting its KPD program, intended primarily to benefit patients who have a low probability of receiving a transplant from a deceased donor.