Vaccination for solid organ transplanted patients: Recommendations, efficacy, and safety

Solid organ transplant recipients face unique challenges in managing their immunosuppressed status, making vaccination a critical consideration. This review aimed to comprehensively analyze current recommendations, evaluate the efficacy of vaccinations in this population, and assess safety concerns. We explored the latest evidence on vaccine types, timing, and potential benefits for transplant patients, highlighting the importance of individualized approaches for routinely used vaccines as well as coronavirus disease 2019 vaccines. By synthesizing available data, this review underscored the pressing need to optimize vaccination strategies, ensuring that transplant recipients can obtain the full protection against many pathogens while minimizing risks associated with their post-transplant immunosuppression.

Graft Survival of En Bloc Deceased Donor Kidneys Transplants Compared With Single Kidney Transplants

BACKGROUND

The US Kidney Allocation System allocates en bloc deceased donor kidney grafts from donors <18 kg in sequence A along with single kidney transplants (SKTs) from kidney donor profile index (KDPI) top 20% donors. Although en bloc grafts outperform SKT grafts holding donor weight constant, it is unclear if en bloc grafts from the smallest pediatric donors perform the same as top 20% KDPI SKTs.

METHODS

Using the Scientific Registry of Transplant Recipients, we compared the donor characteristics and graft survival of en bloc grafts from the smallest donors (<8 kg) and from larger donors (≥8 kg) with SKTs by KDPI sequence for transplants performed in 2021.

RESULTS

Larger donor en blocs had similar 1-y survival to sequence A SKTs estimated by the Kaplan-Meier method (96% versus 96%, P = 0.9), but the smallest donor en blocs had significantly shorter 1-y survival than those SKTs (80% versus 96%, P < 0.01). Using transplants from 2010 to 2012, the smallest donor en blocs had similar 10-y survival to sequence A SKTs (69% versus 64%, P  = 0.3).

CONCLUSIONS

These findings suggest that future updates of the Kidney Allocation System should include a score specific to pediatric donors to account for these differences in en bloc graft survival.

Application of graft-derived cell-free DNA for solid organ transplantation

Monitoring the status of grafts and the occurrence of postoperative complications, such as rejection, is crucial for ensuring the success and long-term survival of organ transplants. Traditional histopathological examination, though effective, is an invasive procedure and poses risks of complications, making frequent use impractical. In recent years, graft-derived cell-free DNA (gd-cfDNA) has emerged as a promising non-invasive biomarker. It not only provides early warnings of rejection and other types of graft injury but also offers important information about the effectiveness of immunosuppressive therapy and prognosis. gd-cfDNA shows potential in the monitoring of organ transplants. The early, real-time information on graft injury provided by gd-cfDNA facilitates timely individualized treatment and improves patient outcomes. However, the progress of research on gd-cfDNA varies across different organs. Therefore, this article will comprehensively review the application and findings of gd-cfDNA in monitoring various solid organs, discussing the advantages, limitations, and some future research directions to aid in its clinical application.

Analysis of the primary factors influencing donor derived cell-free DNA testing in kidney transplantation

The donor-derived cell-free DNA (ddcfDNA) is found in the plasma and urine of kidney transplant recipients and displays notable potential in diagnosing rejection, specifically antibody-mediated rejection (ABMR). Nonetheless, the quantitative methods of ddcfDNA lacking standardization and diverse detection techniques can impact the test outcomes. Besides, both the fraction and absolute values of ddcfDNA have been reported as valuable markers for rejection diagnosis, but they carry distinct meanings and are special in various pathological conditions. Additionally, ddcfDNA is highly sensitive to kidney transplant injury. The various sampling times and combination with other diseases can indeed impact ddcfDNA detection values. This review comprehensively analyses the various factors affecting ddcfDNA detection in kidney transplantation, including the number of SNPs and sequencing depths. Furthermore, different pathological conditions, distinct sampling time points, and the presence of complex heterologous signals can influence ddcfDNA testing results in kidney transplantation. The review also provides insights into ddcfDNA testing on different platforms along with key considerations.

Reproductive Health in Kidney Transplant Recipients

Increasing number of women with kidney transplants are of reproductive age and desire successful pregnancies. Successful outcomes of pregnancy can be achieved with preconception counseling, education about contraception use, the timing of pregnancy (delaying by first year post-transplant), and the choice of immunosuppression medication. Ensuring stable renal function including optimized creatinine, proteinuria, and blood pressure increases successful outcomes. Pregnancy with kidney transplant has an increased risk of preeclampsia, gestational diabetes militeus, cesarean section, and preterm delivery. Multidisciplinary cooperation with high-risk obstetrics and transplant nephrologists is vital.

The Use of Kidneys With Lower Longevity From Deceased Donors to Improve Access to Preemptive Renal Transplantation for Elderly Patients: A Qualitative Study

Background

There is a gap between the number of patients waiting for a transplant and the number of kidneys available. Some deceased donor kidneys are currently nonutilized, as medical teams fear that they will experience suboptimal graft survival. However, these organs could provide an acceptable therapeutic option if they were allocated for preemptive kidney transplantation in elderly candidates.

Objective

This project aims to gather patients' perspectives on the allocation of kidneys with lower longevity for preemptive kidney transplantation in elderly patients.

Design

Individual interviews.

Setting

The Center hospitalier de l'Université de Montréal (CHUM) chronic kidney disease (CKD) clinic.

Participants

Patients aged between 64 and 75 years with CKD G4-5 ND, followed at the CHUM and who have not initiated dialysis yet.

Methods

Between March and July 2023, we conducted 14 individual interviews with patients aged between 64 and 75 years who had CKD G4-5 ND and were followed at the CHUM. The interviews were digitally recorded and transcribed. Thematic analysis was conducted.

Results

Most participants were in favor of using kidneys with lower longevity to increase their access to transplantation, improve their quality of life, enable accelerated transplantation, and avoid dialysis. Patients also wanted to be engaged in the decision-making process, underlining the importance of informed consent. Although the use of kidneys with lower longevity offers the hope of returning to "normal" life, some patients were concerned about the risk of reduced graft survival and the need for a subsequent kidney transplant. In these cases, patients were interested in using mitigation strategies, such as prioritization for kidney transplantation from standard donors in case of early graft loss associated with receiving kidneys with lower longevity. They also recommended the development of a separate waiting list for patients consenting to preemptive transplantation with kidneys with lower longevity.

Limitations

This study was conducted in only 1 nephrology clinic in the province of Quebec with French-speaking patients. Consequently, the results may not be generalizable to other populations, including ethnic minorities.

Conclusion

The use of kidneys with lower longevity for preemptive kidney transplantation appears to be an interesting option for elderly kidney transplant candidates. However, patient information and participation in the decision-making process are essential. Moreover, organ donation organizations and transplant programs should develop a separate waitlist for transplant candidates who have preconsented to receive organ offers of deceased donor kidneys with lower longevity.

Trial registration

Not registered.

Combined Urinary Reconstruction During en Bloc Kidney Transplantation From a Pediatric Donor to an Adult Recipient: A Case Report

Urinary reconstruction during en bloc kidney transplantation is challenging, with different techniques described. Here, we report a case of combined urinary reconstruction using modified Lich ureteroneocystostomy and ureteroureterostomy.

Expanding Access to High KDPI Kidney Transplant for Recipients Aged 60 y and Older: Cost Utility and Survival

Background

Modern organ allocation systems are tasked with equitably maximizing the utility of transplanted organs. Increasing the use of deceased donor organs at risk of discard may be a cost-effective strategy to improve overall transplant benefit. We determined the survival implications and cost utility of increasing the use of marginal kidneys in an older adult Canadian population of patients with end-stage kidney disease.

Methods

We constructed a cost-utility model with microsimulation from the perspective of the Canadian single-payer health system for incident transplant waitlisted patients aged 60 y and older. A kidney donor profile index score of ≥86 was considered a marginal kidney. Donor- and recipient-level characteristics encompassed in the kidney donor profile index and estimated posttransplant survival scores were used to derive survival posttransplant. Patients were followed up for 10 y from the date of waitlist initiation. Our analysis compared the routine use of marginal kidneys (marginal kidney scenario) with the current practice of limited use (status quo scenario).

Results

The 10-y mean cost and quality-adjusted life-years per patient in the marginal kidney scenario were estimated at $379 485.33 (SD: $156 872.49) and 4.77 (SD: 1.87). In the status quo scenario, the mean cost and quality-adjusted life-years per patient were $402 937.68 (SD: $168 508.85) and 4.37 (SD: 1.87); thus, the intervention was considered dominant. At 10 y, 62.8% and 57.0% of the respective cohorts in the marginal kidney and status quo scenarios remained alive.

Conclusions

Increasing the use of marginal kidneys in patients with end-stage kidney disease aged 60 y and older may offer cost savings, improved quality of life, and greater patient survival in comparison with usual care.

Long-term outcomes of two-dose alemtuzumab induction in pediatric kidney transplantation

BACKGROUND

Alemtuzumab is a lymphocyte depleting agent used for induction in kidney transplant, but long-term information on its use in pediatric recipients remains sparse.

METHODS

We performed a single-center retrospective cohort study of 57 pediatric kidney transplant recipients receiving alemtuzumab 20 mg/m2/dose ×2 doses for induction immunosuppression. All patients underwent surveillance biopsies, and 91.3% underwent steroid withdrawal by day 4 post-transplant. Outcomes of interest included graft survival, development of donor specific antibodies (DSA), incidence of viremia and PTLD, and duration of lymphopenia.

RESULTS

Median follow-up time was 7.9 years (IQR 5-13.6 years). Median graft survival was 16.5 years (95% CI 11.6-unknown). DSA developed in 36.5% at a median of 944 days (IQR 252-2113 days). Incidences of BK polyomavirus DNAemia (BKPyV-DNAemia), CMV DNAemia, and EBV DNAemia were 38.6%, 22.8%, and 14%, respectively; one patient developed PTLD at 13.3 years post-transplant. Median duration of lymphopenia was 365 days (IQR 168-713 days); 19.3% of patients remained lymphopenic at 3 years post-transplant. There was no association between duration of lymphopenia and graft survival, rejection, DSA detection, or viremia.

CONCLUSIONS

A two-dose alemtuzumab induction protocol can have excellent outcomes with a steroid-free maintenance immunosuppression regimen. More comprehensive, multicenter, comparative studies of pediatric kidney transplant are needed to improve long-term outcomes.

Interaction between cold ischemia time and Kidney Donor Profile Index on postrenal transplant outcomes

We analyzed whether there is an interaction between the Kidney Donor Profile Index (KDPI) and cold ischemia time (CIT) in recipients of deceased donor kidney transplant (KTs). Adults who underwent KTs in the United States between 2014 and 2020 were included and divided into 3 KDPI groups (≤20%, 21%-85%, >85%) and 4 CIT strata (<12, 12-17.9, 18-23.9, ≥24 hours). Multivariate analyses were used to test the interaction between KDPI and CIT for the following outcomes: primary graft nonfunction (PGNF), delayed graft function (DGF), estimated glomerular filtration rate (eGFR) at 6 and 12 months, patient survival, graft survival, and death-censored graft survival (DCGS). A total of 69,490 recipients were analyzed: 18,241 (26.3%) received a graft with KDPI ≤20%, 46,953 (67.6%) with KDPI 21%-85%, and 4,296 (6.2%) with KDPI >85%. Increasing KDPI and CIT were associated with worse post-KT outcomes. Contrary to our hypothesis, howerver, the interaction between KDPI and CIT was statistically significant only for PGNF and DGF and eGFR at 6 months. Paradoxically, the negative coefficient of the interaction suggested that increasing duration of CIT was more detrimental for low and intermediate-KDPI organs relative to high-KDPI grafts. Conversely, for mortality, graft survival, and DCGS, we found that the interaction between CIT and KDPI was not statistically significant. We conclude that, high KDPI and prolonged CIT are independent risk factors for inferior outcomes after KT. Their interaction, however, is statistically significant only for the short-term outcomes and more pronounced on low and intermediate-KDPI grafts than high-KDPI kidneys.

Pediatric en bloc kidney transplant from donors <15 kg: An excellent approach to expand the pediatric deceased donor pool

INTRODUCTION

Most kidneys from small pediatric donors are transplanted to adult recipients because of the perceived risk of surgical complications and graft thrombosis. In this study, we aim to demonstrate our favorable outcomes in transplanting pediatric kidneys from donors <15 k into pediatric recipients.

METHODS

This study retrospectively analyzes the outcomes of seven pediatric recipients of en block kidney transplants from pediatric donors weighing <15 kg performed at King Fahad Specialist Hospital-Dammam from December 2014 to January 2018. Baseline characteristics of donors and recipients were collected. The incidences of surgical complication, immediate, and intermediate graft function were the primary outcomes.

RESULTS

The study included seven recipients monitored for a mean duration of 6.86 ± 1.35. Donors' and recipients' mean weights were 7.4 ± 3.2 kg and 20.7 ± 9.2 kg, respectively. Ureteric stricture occurred in one patient. There was a substantial improvement of 1-year estimated glomerular filtration rate (eGFR) compared to the 1-week mark (106.7 ± 26.38 mL/min. 1.73 m2 vs. 63.7 ± 22.92 mL/min/1.73 m2, p = .0069). The observed improvement in renal function persisted at the 5-year mark and during the last follow-up, with eGFR of 70.3 ± 40.7 mL/min/1.73 m2, and 79.8 ± 30.8 mL/min/1.73 m2, respectively. There was also increase of 27.9% in the size of the en bloc kidney observed at the 6 months.

CONCLUSION

In a specialized transplant center with highly skilled surgeons, the utilization of en bloc kidney transplant from donors weighing less than 15 kg is an effective strategy for expanding the donor pool and ensuring favorable graft outcomes.

Predicting Kidney Transplantation Outcomes from Donor and Recipient Characteristics at Time Zero: Development of a Mobile Application for Nephrologists

(1) Background: We report on the development of a predictive tool that can estimate kidney transplant survival at time zero. (2) Methods: This was an observational, retrospective study including 5078 transplants. Death-censored graft and patient survivals were calculated. (3) Results: Graft loss was associated with donor age (hazard ratio [HR], 1.021, 95% confidence interval [CI] 1.018-1.024, p < 0.001), uncontrolled donation after circulatory death (DCD) (HR 1.576, 95% CI 1.241-2.047, p < 0.001) and controlled DCD (HR 1.567, 95% CI 1.372-1.812, p < 0.001), panel reactive antibody percentage (HR 1.009, 95% CI 1.007-1.011, p < 0.001), and previous transplants (HR 1.494, 95% CI 1.367-1.634, p < 0.001). Patient survival was associated with recipient age (> 60 years, HR 5.507, 95% CI 4.524-6.704, p < 0.001 vs. < 40 years), donor age (HR 1.019, 95% CI 1.016-1.023, p < 0.001), dialysis vintage (HR 1.0000263, 95% CI 1.000225-1.000301, p < 0.01), and male sex (HR 1.229, 95% CI 1.135-1.332, p < 0.001). The C-statistics for graft and patient survival were 0.666 (95% CI: 0.646, 0.686) and 0.726 (95% CI: 0.710-0.742), respectively. (4) Conclusions: We developed a mobile app to estimate survival at time zero, which can guide decisions for organ allocation.

Levels of Cell-Free DNA in Kidney Failure Patients before and after Renal Transplantation

Circulating cell-free DNA (cfDNA) has diverse applications in oncological, prenatal, toxicological, cardiovascular, and autoimmune diseases, diagnostics, and organ transplantation. In particular, mitochondrial cfDNA (mt-cfDNA) is associated with inflammation and linked to early vascular ageing (EVA) in end-stage kidney failure (ESKF), which could be a noninvasive marker for graft rejection and organ damage. Plasma samples from 44 ESKF patients, of whom half (n = 22) underwent either conservative therapy (non-HD) or hemodialysis (HD) before kidney transplantation (KT). These samples were analyzed at baseline and two years after KT. cfDNA was extracted from plasma and quantified using the fluorometric method. qPCR was used to quantify and differentiate the fractions of mt-cfDNA and nuclear cfDNA (nc-cfDNA). mt-cfDNA levels in KT patients decreased significantly from baseline to two years post-KT (p < 0.0268), while levels of total cfDNA and nc-cfDNA did not differ. Depending on therapy modality (HD vs. non-HD) before KT, total cfDNA levels were higher in HD patients at both baseline (p = 0.0133) and two years post-KT (p = 0.0421), while nc-cfDNA levels were higher in HD only at baseline (p = 0.0079). Males showed a nonsignificant trend of higher cfDNA levels. Patients with assessed vascular fibrosis (p = 0.0068), either alone or in combination with calcification plus fibrosis, showed reduced mt-cfDNA post-KT (p = 0.0195). Changes in mt-cfDNA levels suggests the impact of KT on the inflammatory state of ESKF, as evidenced via its correlation with high sensitivity C-reactive protein after KT. Further studies are warranted to assess if cfDNA could serve as a noninvasive method for monitoring the response to organ transplantation and even for amelioration of EVA status per se.

Evaluating Cost-Effectiveness in Using High-Kidney Donor Profile Index Organs

A more granular donor kidney grading scale, the kidney donor profile index (KDPI), has recently emerged in contradistinction to the standard criteria donor/expanded criteria donor framework. In this paper, we built a Markov decision process model to evaluate the survival, quality-adjusted life years (QALY), and cost advantages of using high-KDPI kidneys based on multiple KDPI strata over a 60-month time horizon as opposed to remaining on the waiting list waiting for a lower-KDPI kidney. Data for the model were gathered from the Scientific Registry of Transplant Recipients and the United States Renal Data System Medicare parts A, B, and D databases. Of the 129,024 phenotypes delineated in this model, 65% of them would experience a survival benefit, 81% would experience an increase in QALYs, 87% would see cost-savings, and 76% would experience cost-savings per QALY from accepting a high-KDPI kidney rather than remaining on the waiting list waiting for a kidney of lower-KDPI. Classification and regression tree analysis (CART) revealed the main drivers of increased survival in accepting high-KDPI kidneys were wait time ≥30 months, panel reactive antibody (PRA) <90, age ≥45 to 65, diagnosis leading to renal failure, and prior transplantation. The CART analysis showed the main drivers of increased QALYs in accepting high-kidneys were wait time ≥30 months, PRA <90, and age ≥55 to 65.

Intention-to-treat Analysis of Patients Aged 70 Years and Older Awaiting Kidney Transplantation in Post-Kidney Allocation System Era

BACKGROUND

The US population is aging, and so the number of patients treated for end-stage renal disease is on the rise. In the United States, 38% of people over 65 y old have chronic kidney disease. There continues to be a reluctance of clinicians to consider older candidates for transplant, including early referrals.

METHODS

We conducted a retrospective analysis of the Organ Procurement and Transplantation Network database of all adults ≥70 y old undergoing kidney transplants from December 1, 2014, to June 30, 2021. We compared patient and graft survival in candidates who were transplanted while on hemodialysis versus preemptive with a living versus deceased donor kidney transplant.

RESULTS

In 2021, only 43% of the candidates listed for transplant were preemptive. In an intention-to-treat analysis from the time of listing, candidate survival was significantly improved for those transplanted preemptively versus being on dialysis (hazard ratio 0.59; confidence interval, 0.56-0.63). All donor types, donor after circulatory death, donor after brain death, and living donor, had a significant decrease in death over remaining on the waiting list. Patients who were on dialysis or transplanted preemptively with a living donor kidney had significantly better survival than those receiving a deceased donor kidney. However, receiving a deceased donor kidney significantly decreased the chance of death over remaining on the waiting list.

CONCLUSIONS

Patients ≥70 y old who are transplanted preemptively, whether with a deceased donor or a living donor kidney, have a significantly better survival than those who are transplanted after initiating dialysis. Emphasis on timely referral for a kidney transplant should be placed in this population.

The use of lymphocyte-depleting antibodies in specific populations of kidney transplant recipients: A systematic review and meta-analysis

BACKGROUND

Recommendations of the use of antibody induction treatments in kidney transplant recipients (KTR) are based on moderate quality and historical studies. This systematic review aims to reevaluate, based on actual studies, the effects of different antibody preparations when used in specific KTR subgroups.

METHODS

We searched MEDLINE and CENTRAL and selected randomized controlled trials (RCT) and observational studies looking at different antibody preparations used as induction in KTR. Comparisons were categorized into different KTR subgroups: standard, high risk of rejection, high risk of delayed graft function (DGF), living donor, and elderly KTR. Two authors independently assessed the risk of bias.

RESULTS

Thirty-seven RCT and 99 observational studies were finally included. Compared to anti-interleukin-2-receptor antibodies (IL2RA), anti-thymocyte globulin (ATG) reduced the risk of acute rejection at two years in standard KTR (RR 0.74, 95%CI 0.61-0.89) and high risk of rejection KTR (RR 0.55, 95%CI 0.43-0.72), but without decreasing the risk of graft loss. We did not find significant differences comparing ATG vs. alemtuzumab or different ATG dosages in any KTR group.

CONCLUSIONS

Despite many studies carried out on induction treatment in KTR, their heterogeneity and short follow-up preclude definitive conclusions to determine the optimal induction therapy. Compared with IL2RA, ATG reduced rejection in standard-risk, highly sensitized, and living donor graft recipients, but not in high DGF risk or elderly recipients. More studies are needed to demonstrate beneficial effects in other KTR subgroups and overall patient and graft survival.

What are the benefits of preemptive versus non-preemptive kidney transplantation? A systematic review and meta-analysis

Opting for a preemptive kidney transplant (PKT) can help avoid costs and morbidity associated with dialysis. However, while multiple studies have shown clinical benefits of PKT, other studies have not demonstrated this, leading to controversy in the literature regarding the exact benefits of PKT. Therefore, this study aimed to determine the clinical outcomes of PKT versus non-preemptive kidney transplantation (nPKT) in adult patients. Multiple databases were searched up to May 4, 2022. Independent reviewers selected studies for inclusion and extracted relevant data. Risk of bias was assessed using the Downs and Black checklist. Eighty-seven studies including 859,715 adult kidney transplant patients were included the review. The risk of patient death (relative risk [95% confidence interval] 0.74 [0.60-0.91]) was significantly lower in PKT versus nPKT patients for living donor (LD) transplants, whereas the risk of overall graft loss was significantly lower in PKT compared to nPKT patients for both LD (0.72 [0.62-0.83]) as well as deceased donor (DD) transplants (0.80 [0.69-0.92]). The evidence suggests that LD PKT patients have a lower risk of patient death and graft loss compared to nPKT patients, and DD PKT patients have a lower risk of graft loss than nPKT patients.

Humoral and Cellular Immunity Are Significantly Affected in Renal Transplant Recipients, following Vaccination with BNT162b2

BACKGROUND

Renal transplant recipients (RTRs) tend to mount weaker immune responses to vaccinations, including vaccines against the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

Humoral immunity was assessed using anti-receptor binding domain (RBD) and neutralizing antibodies (NAb) serum levels measured by ELISA, and cellular immunity was assessed using T-, B-, NK, natural killer-like T (NKT)-cell subpopulations, and monocytes measured by flow cytometry, and also specific T-cell immunity, at predefined time points after BNT162b2 vaccination, in 57 adult RTRs.

RESULTS

Administration of three booster doses was necessary to achieve anti-RBD and NAb protective levels in almost all patients (92.98%). Ab production, at several time points, was positively correlated with the corresponding renal function and inversely correlated with hemodialysis vintage (HDV) and treatment with mycophenolic acid (MPA). A gradual rise in several cell subpopulations, including total lymphocytes (p = 0.026), memory B cells (p = 0.028), activated CD4 (p = 0.005), and CD8 cells (p = 0.001), was observed even after the third vaccination dose, while a significant reduction in CD3+PD1+ (p = 0.002), NKT (p = 0.011), and activated NKT cells (p = 0.034) was noted during the same time interval. Moreover, SARS-CoV-2-specific T-cells were present in 41% of the patients who were unable to develop Nabs, and their positivity rates four months after the second dose were in inverse correlation with monocytes (p = 0.045) and NKT cells (p = 0.01).

CONCLUSIONS

SARS-CoV-2-specific T-cell responses preceded the humoral ones, while two booster doses were needed for this group of immunocompromised patients to mount a protective immune response.

Vaccination Recommendations in Solid Organ Transplant Adult Candidates and Recipients

Prevention of infections is crucial in solid organ transplant (SOT) candidates and recipients. These patients are exposed to an increased infectious risk due to previous organ insufficiency and to pharmacologic immunosuppression. Besides infectious-related morbidity and mortality, this vulnerable group of patients is also exposed to the risk of acute decompensation and organ rejection or failure in the pre- and post-transplant period, respectively, since antimicrobial treatments are less effective than in the immunocompetent patients. Vaccination represents a major preventive measure against specific infectious risks in this population but as responses to vaccines are reduced, especially in the early post-transplant period or after treatment for rejection, an optimal vaccination status should be obtained prior to transplantation whenever possible. This review reports the currently available data on the indications and protocols of vaccination in SOT adult candidates and recipients.

Preventing Rejection of the Kidney Transplant

With increasing knowledge of immunologic factors and with the advent of potent immunosuppressive agents, the last several decades have seen significantly improved kidney allograft survival. However, despite overall improved short to medium-term allograft survival, long-term allograft outcomes remain unsatisfactory. A large body of literature implicates acute and chronic rejection as independent risk factors for graft loss. In this article, we review measures taken at various stages in the kidney transplant process to minimize the risk of rejection. In the pre-transplant phase, it is imperative to minimize the risk of sensitization, aim for better HLA matching including eplet matching and use desensitization in carefully selected high-risk patients. The peri-transplant phase involves strategies to minimize cold ischemia times, individualize induction immunosuppression and make all efforts for better HLA matching. In the post-transplant phase, the focus should move towards individualizing maintenance immunosuppression and using innovative strategies to increase compliance. Acute rejection episodes are risk factors for significant graft injury and development of chronic rejection thus one should strive for early detection and aggressive treatment. Monitoring for DSA development, especially in high-risk populations, should be made part of transplant follow-up protocols. A host of new biomarkers are now commercially available, and these should be used for early detection of rejection, immunosuppression modulation, prevention of unnecessary biopsies and monitoring response to rejection treatment. There is a strong push needed for the development of new drugs, especially for the management of chronic or resistant rejections, to prolong graft survival. Prevention of rejection is key for the longevity of kidney allografts. This requires a multipronged approach and significant effort on the part of the recipients and transplant centers.

Long-term Outcomes of Single and Dual En Bloc Kidney Transplants From Small Pediatric Donors: An ANZDATA Registry Study

Kidney transplants from small pediatric donors are considered marginal and often transplanted as dual grafts. This study aimed to compare long-term outcomes between recipients of single kidney transplants (SKTs) and dual en bloc kidney transplants (EBKTs) from small pediatric donors.

Methods

Data were obtained from the Australia and New Zealand Dialysis and Transplant Registry. All adult recipients of kidney transplants from donors aged ≤5 y were identified. The primary outcome of interest was death-censored graft survival by donor type. The secondary outcomes were early graft loss, delayed graft function, serum creatinine posttransplantation, acute rejection, and patient survival.

Results

There were 183 adult recipients of kidney transplants from donors aged ≤5 y old. Of these, 60 patients had EBKT grafts, 79 patients had SKT grafts, and 44 patients had grafts of unknown type. Compared with SKT donors, EBKT donors had lower mean age (P < 0.001) and body weight (P < 0.001). There was no significant difference in death-censored graft survival between the groups, with median survival of 23.8 y (interquartile range 21.2-25) in the EBKT cohort and 21.8 y (11.6-26.8) in the SKT cohort (hazard ratio 1.3; 95% confidence interval, 0.59-2.64; P = 0.56). EBKT grafts had lower acute rejection rates than SKT grafts (P = 0.014). There was no significant difference observed between groups with respect to early graft loss, delayed graft function, posttransplantation serum creatinine posttransplantation, or patient survival.

Conclusions

EBKT and SKTs from small pediatric donors are associated with excellent long-term graft survival rates.

Hepatitis B Virus Reactivation in Kidney Transplant Recipients Treated With Belatacept

Introduction

Hepatitis B virus (HBV) reactivation in kidney transplant recipients has been reported in 3% to 9% of anti-HBc antibody (HBcAb)-positive HBs antigen (HBsAg)-negative patients. It has not been studied in patients receiving belatacept, a selective costimulation blocker.

Methods

We performed a retrospective study of all transplant recipients receiving belatacept in 2 kidney transplantation centers in France. Among HBcAb-positive patients, we analyzed HBV reactivation rate, outcomes, and risk factors.

Results

A total of 135 patients treated with belatacept were included: 32 were HBcAb-positive and 2 were HBsAg-positive. Seven patients reactivated HBV (21.9% of HBcAb-positive patients), including 5 HBsAg-negative patients (16.7% of HBcAb-positive HBsAg-negative patients). Reactivation occurred 54.8 (± 70.9) months after transplantation. One patient presented with severe hepatitis and 1 patient developed cirrhosis. There was no significant difference in survival between patients that reactivated HBV and patients that did not: 5-year patient survival of 100% (28.6; 100) and 83.4% (67.6; 100), respectively (P = 0.363); and 5-year graft survival of 100% (28.6; 100) and 79.8% (61.7; 100), respectively (P = 0.335). No factor, including HBsAb positivity and antiviral prophylaxis, was statistically associated with the risk of HBV reactivation.

Conclusion

HBV reactivation rate was high in patients treated with belatacept when compared with previous transplantation studies. HBV reactivation did not impact survival. Further studies are needed to confirm these results. A systematic antiviral prophylaxis for these patients should be considered and evaluated.

Dual Kidney Transplantation: Single-Center Experience

BACKGROUND

Dual and en bloc kidney transplantation are strategies used to mitigate the disparity between a reduced organ pool and an ever-increasing need for organ procurement. En bloc refers to the implantation of 2 kidneys from a pediatric donor, compensating for small renal mass, whereas dual expanded criteria donor (DECD) transplantation refers to older donors with grafts otherwise rejected for single transplant, including expanded. This study describes one center's experience with dual and en bloc transplantation.

METHODS

A retrospective cohort study of dual kidney transplants (en bloc and DECD) from 1990 through 2021. The analysis included demographic, clinical, and survival analysis.

RESULTS

Of 46 patients who underwent dual kidney transplantation, 17 (37 %) received en-bloc transplantation. The overall mean recipient age was 49.4 ± 13.9 years old, younger in the en-bloc subgroup (39.2 vs 59.8 years old, P < .01). The mean time on dialysis was 37 ± 25 months. Delayed graft function was present in 17.4 % and primary nonfunction in 6.4 %, all from the DECD group. The estimated glomerular filtration rates at 1 and 5 years were 76.7 ± 28.7 and 80.4 ± 24.8 mL/min/1.73 m2, lower in the DECD group (65.9 vs 88.7 mL/min/1.73 m2, P = 0.02). Eleven recipients lost their graft during the study period: 63.6% from death with a functioning graft, 27.3% due to chronic graft dysfunction (a mean of 76.3 months after transplantation), and 9.1% due to vascular complications. Subgroup comparison found no differences regarding cold ischemia time or length of hospitalization. Kaplan-Meier estimates, censored for death with a functioning graft, resulted in a mean graft survival of 21.3 ± 1.3 years, with survival rates of 93.5, 90.5, and 84.1% at 1, 5, and 10 years, respectively, without significant differences between subgroups.

CONCLUSIONS

Both DECD and en bloc strategies provide safe and effective options to further expand the use of otherwise rejected kidneys. Neither of the 2 techniques was superior to the other.

All That Glitters in cfDNA Analysis Is Not Gold or Its Utility Is Completely Established Due to Graft Damage: A Critical Review in the Field of Transplantation

In kidney transplantation, a biopsy is currently the gold standard for monitoring the transplanted organ. However, this is far from an ideal screening method given its invasive nature and the discomfort it can cause the patient. Large-scale studies in renal transplantation show that approximately 1% of biopsies generate major complications, with a risk of macroscopic hematuria greater than 3.5%. It would not be until 2011 that a method to detect donor-derived cell-free DNA (dd-cfDNA) employing digital PCR was devised based on analyzing the differences in SNPs between the donor and recipient. In addition, since the initial validation studies were carried out at the specific moments in which rejection was suspected, there is still not a good understanding of how dd-cfDNA levels naturally evolve post-transplant. In addition, various factors, both in the recipient and the donor, can influence dd-cfDNA levels and cause increases in the levels of dd-cfDNA themselves without suspicion of rejection. All that glitters in this technology is not gold; therefore, in this article, we discuss the current state of clinical studies, the benefits, and disadvantages.

Preemptive living donor kidney transplantation: Access, fate, and review of the status in Egypt

BACKGROUND

Preemptive living donor kidney transplantation (PLDKT) is recommended as the optimal treatment for end-stage renal disease.

AIM

To assess the rate of PLDKT among patients who accessed KT in our center and review the status of PLDKT in Egypt.

METHODS

We performed a retrospective review of the patients who accessed KT in our center from November 2015 to November 2022. In addition, the PLDKT status in Egypt was reviewed relative to the literature.

RESULTS

Of the 304 patients who accessed KT, 32 patients (10.5%) had preemptive access to KT (PAKT). The means of age and estimated glomerular filtration rate were 31.7 ± 13 years and 12.8 ± 3.5 mL/min/1.73 m², respectively. Fifty-nine patients had KT, including 3 PLDKTs only (5.1% of total KTs and 9.4% of PAKT). Twenty-nine patients (90.6%) failed to receive PLDKT due to donor unavailability (25%), exclusion (28.6%), regression from donation (3.6%), and patient regression on starting dialysis (39.3%). In multivariate analysis, known primary kidney disease (P = 0.002), patient age (P = 0.031) and sex (P = 0.001) were independent predictors of achievement of KT in our center. However, PAKT was not significantly (P = 0.065) associated with the achievement of KT. Review of the literature revealed lower rates of PLDKT in Egypt than those in the literature.

CONCLUSION

Patient age, sex, and primary kidney disease are independent predictors of achieving living donor KT. Despite its non-significant effect, PAKT may enhance the low rates of PLDKT. The main causes of non-achievement of PLDKT were patient regression on starting regular dialysis and donor unavailability or exclusion.

The Benefits of Preemptive Transplantation Using High-Kidney Donor Profile Index Kidneys

BACKGROUND

The Kidney Donor Profile Index (KDPI) is a percentile score summarizing the likelihood of allograft failure: A KDPI ≥85% is associated with shorter allograft survival, and 50% of these donated kidneys are not currently used for transplantation. Preemptive transplantation (transplantation without prior maintenance dialysis) is associated with longer allograft survival than transplantation after dialysis; however, it is unknown whether this benefit extends to high-KDPI transplants. The objective of this analysis was to determine whether the benefit of preemptive transplantation extends to recipients of transplants with a KDPI ≥85%.

METHODS

This retrospective cohort study compared the post-transplant outcomes of preemptive and nonpreemptive deceased donor kidney transplants using data from the Scientific Registry of Transplant Recipients. 120,091 patients who received their first, kidney-only transplant between January 1, 2005, and December 31, 2017, were studied, including 23,211 with KDPI ≥85%. Of this cohort, 12,331 patients received a transplant preemptively. Time-to-event models for the outcomes of allograft loss from any cause, death-censored graft loss, and death with a functioning transplant were performed.

RESULTS

Compared with recipients of nonpreemptive transplants with a KDPI of 0%-20% as the reference group, the risk of allograft loss from any cause in recipients of a preemptive transplant with KDPI ≥85% (hazard ratio [HR], 1.51; 95% confidence interval [CI], 1.39 to 1.64) was lower than that in recipients of nonpreemptive transplant with a KDPI ≥85% (HR, 2.39; 95% CI, 2.21 to 2.58) and similar to that of recipients of a nonpreemptive transplant with a KDPI of 51%-84% (HR, 1.61; 95% CI, 1.52 to 1.70).

CONCLUSIONS

Preemptive transplantation is associated with a lower risk of allograft failure, irrespective of KDPI, and preemptive transplants with KDPI ≥85% have comparable outcomes with nonpreemptive transplants with KDPI 51%-84%.

Evaluation of technical urinary tract complications in kidney transplantation recipients with a prolonged dialysis history

BACKGROUND

The kidney transplant waiting list continues to expand, resulting in prolonged dialysis times exceeding 8 years before transplantation in some regions. The relationship between long-term dialysis and urinary tract complications after kidney transplant remains largely unexplored. This study aims to evaluate post-kidney transplant complications in patients with a history of prolonged dialysis.

METHODS

A single-center, retrospective cohort study of patients maintained on dialysis ≥8 years before kidney transplant between January 2000 and July 2020 was conducted. Clinical variables, including demographics and comorbidities, were reviewed. The primary objective was the development of a technical urinary tract complication. Secondary outcomes included any postoperative complication by type, stratified by medical and surgical complications.

RESULTS

Overall, 376 patients met the inclusion criteria. The mean pre-kidney transplant dialysis time was 10.2 ± 2.6 years. The majority (65.7%) of the study participants were anuric. Four patients (1.1%) experienced a urine leak, and 8 patients (2.1%) had a ureteral stricture. Any complication was observed in 111 (29.5%) patients, with urinary tract infections being the most common. Urinary catheters remained in place for a median of 4 (3, 5) days. Drains were commonly used (62.8%) for a median of 5 (4, 6) days.

CONCLUSION

In our large, single-center experience with kidney transplants in high-risk patients with prolonged dialysis and anuria, the technical urinary tract complications rate remained low. With the current literature consisting of small cohorts and having relatively short pre-kidney transplant dialysis periods, our analysis addresses the shortcomings of the literature while suggesting that this patient population may not truly be "high risk."

An Initial Analysis of the Baseline Levels of Dd-cfDNA After Pancreas Transplantation: A Prospective Study From High-volume Centers in the United States

Pancreas transplantation offers patients with diabetes an opportunity for glucose homeostasis. Current blood tests to surveil for rejection have poor sensitivity and specificity for identifying rejection, and pancreas biopsies are challenging and associated with morbidity and graft loss. Donor-derived cell-free DNA (dd-cfDNA) is shed from transplanted organs and detectable in peripheral blood. Thus, a potential dd-cfDNA blood test assessing rejection would be clinically advantageous.

Methods

One hundred eighty-one dd-cfDNA samples (n) were collected from 77 patients (N) up to 132 mo posttransplant.

Results

The median dd-cfDNA level among all subjects was 0.28% (0.13%, 0.71%). In simultaneous pancreas-kidney (SPK) transplant recipients, the median dd-cfDNA level was 0.29% (0.13%, 0.71%), and it was 0.23% (0.08%, 0.71%) in pancreas transplant alone (PTA) recipients. When isolating for when without infection or rejection, the median dd-cfDNA level was 0.28% (0.13%, 0.64%) for SPK and 0.20% (0.00%, 0.32%) for PTA. Both transplant types approached 1.0% ≤1 mo posttransplant followed by a decrease in median dd-cfDNA. During episodes of rejection or infection, median dd-cfDNA levels were greater among all transplant types.

Conclusions

The mean dd-cfDNA level for all pancreas transplant recipients is <1.0%, consistent with the published kidney transplant rejection threshold (>1.0%), regardless of SPK or PTA. Early posttransplant dd-cfDNA levels are transiently higher than later measurements. Dd-cfDNA elevation also correlates with rejection and infection and thus is a promising biomarker for surveilling pancreas transplant dysfunction.

Long-term Survival of Grafts From Small and Very Small Pediatric Donors in Women vs Men With End-stage Kidney Disease

This cohort study compares graft survival of kidneys from small and very small pediatric donors in women vs men with end-stage kidney disease.

Excellent Clinical Long-Term Outcomes of Kidney Transplantation From Small Pediatric Donors (Age ≤ 5 Years) Despite Early Hyperfiltration Injury

Background:

The use of small pediatric donors (age ≤ 5 years and body weight < 20kg) for adult transplant recipients is still regarded controversially in terms of early complications, long-term outcomes, and development of hyperfiltration injury due to body size mismatch.

Objective:

To investigate long-term outcomes of adult renal allograft recipients receiving a kidney from small pediatric donor (SPD) in terms of kidney function and early features of hyperfiltration injury such as histological changes and proteinuria.

Design:

Retrospective, single center study.

Settings:

Transplant center of the University Hospital of Basel, Switzerland.

Patients:

Adult renal allograft recipients receiving a kidney from a small pediatric donor at our center between 2005 and 2017.

Methods:

The outcome of 47 transplants from SPD were compared with 153 kidney transplants from deceased-standard criteria donors (SCD) occurring during the same time period. Incidence of clinical signs of hyperfiltration injury (eg, proteinuria) was investigated. According to our policy, surveillance biopsies were taken at 3 and 6 months post-transplant and were evaluated in terms of signs of hyperfiltration injury.

Results:

At a median follow-up of 2.3 years post-transplant, death-censored graft survival of SPD was comparable to transplants from SCD (94% vs 93%; P = .54). Furthermore, allograft function at last follow-up (estimated glomerular filtration rate–Modification of Diet in Renal Disease) was significantly higher in pediatric transplant (80 vs 55 ml/min/1.73 m2, P = .002). We found histological signs of early hyperfiltration injury in 55% of SPD. There was an equally low proteinuria in both groups during follow-up.

Limitations:

It is a single center and retrospective observational study with small sample size. The outcomes were investigated in a well-selected population of recipients with low body mass index, low immunological risk, and well-controlled hypertension and was not compared with equal selected group of recipients.

Conclusions:

Early histological and clinical signs of hyperfiltration injury in SPD is frequent. Despite the hyperfiltration injury, there is an equal allograft survival and even superior allograft function in SPD compared with SCD during follow-up. This observation supports the concept of high adaptive capacity of pediatric donor kidneys.

Serologic evaluation of vaccine preventable infections and vaccination rates in kidney transplant candidates

INTRODUCTION

Assessing vaccine serologic status presents opportunities to provide live vaccinations to kidney transplant candidates (KTC). This is especially important given the increased risk of infection while taking lifelong immunosuppression following transplant and the inability to routinely provide live vaccines to patients on immunosuppressive medications. In March 2019, the American Society of Transplantation Infectious Disease Community of Practice (AST-IDCOP) released updated guidelines for vaccination of KTC, which emphasize pretransplant viral serology screening and live vaccine administration prior to transplant.

PRIMARY ENDPOINT

The primary endpoint of this study was to determine adherence to AST-IDCOP guidelines for live measles, mumps, and rubella (MMR) and VZV vaccination prior to transplant in KTC non-immune by serology.

METHODS

This retrospective, descriptive study examined serologic status and rates of live vaccination in 672 patients listed for kidney transplant at our center between July 2014 and July 2019. Secondary endpoints included subgroup analysis of adherence to full AST-IDCOP vaccination recommendations and validation of CDC presumed immunity definitions for measles and VZV.

RESULTS

Seventeen patients (2.7%) were nonimmune by serology for VZV, while 182 (27.1%) were nonimmune by serology to MMR. In a subgroup analysis of the seronegative KTC, none received VZV vaccination, and 6% received MMR vaccination prior to transplant or last follow-up.

CONCLUSIONS

Overall, a large portion of KTC had immunity gaps that were not resolved before transplantation. These findings are limited due to the retrospective, single-center nature of this study and should be confirmed with larger, prospective assessments of serologic status and vaccine administration.

En Bloc Kidney Transplantation: A Retrospective Study of an 18-year Experience in a Single Institution

Background

Renal transplantation is facing a shortage of grafts. En bloc kidney transplantation (EBKT) from pediatric donors could increase the number of available grafts.

Objective

To describe the surgical technique as well as the long-term functional and morphological results of EBKT.

Design setting and participants

We performed a retrospective study of all the EBKT procedures performed in Lyon between 2002 and 2020. Electronic medical records were checked with an analysis of demographics, and peri- and postoperative results.

Outcome measurements and statistical analysis

A descriptive analysis of donor and recipient characteristics, perioperative data, complications, and renal function was performed.

Results and limitations

Between 2002 and 2020, 21 EBKT procedures were performed. Donors had a mean weight of 8.6 kg and a mean age of 12 mo, with a mean cold ischemia time of 11 h and 30 min. Receivers had a mean age of 30 yr and a body mass index of 20. The mean follow-up time was 62 mo, with patient survival of 100% and graft survival of 95%. There were 13 reinterventions comprising one early unilateral transplantectomy for thrombosis. Renal function was excellent, and the morphological findings described an important growth in size in the first 2 yr before attaining the adult size. This study's limitations include its retrospective nature and a small number of participants.

Conclusions

The present study reports excellent results with EBKT and supports the pursuit and spread of this technique.

Patient summary

In this report, we describe the technique and results of en bloc kidney transplantation. We found that results are excellent for renal function and patient survival. We conclude that en bloc kidney transplantation should be considered to increase the number of grafts.

Cold Ischemia Time, Kidney Donor Profile Index, and Kidney Transplant Outcomes: A Cohort Study

Rationale & Objective

An average of 3,280 recovered deceased donor kidneys are discarded annually in the United States. Increased cold ischemia time is associated with an increased rate of organ decline and subsequent discard. Here we examined the effect of prolonged cold ischemia time on kidney transplant outcomes.

Study Design

Retrospective observational study.

Setting & Participants

Recipients of deceased donor kidney transplants in the United States from 2000 to 2018.

Exposure

Recipients of deceased donor kidneys were divided based on documented cold ischemia time: ≤16, 16-24, 24-32, 32-40, and >40 hours.

Outcomes

The incidence of delayed graft function, primary nonfunction, and 10-year death-censored graft survival.

Analytical Approach

The Kaplan-Meier method was used to generate survival curves, and the log rank test was used to compare graft survival.

Results

The rate of observed delayed graft function increased with cold ischemia time (20.9%, 28.1%, 32.4%, 37.5%, and 35.8%). Primary nonfunction also showed a similar increase with cold ischemia time (0.6%, 0.9%, 1.3%, 2.1%, and 2.3%), During a median follow-up time of 4.6 years, 37,301 recipients experienced death-censored graft failure. Analysis based on kidney donor profile index (KDPI) demonstrated significant differences in 10-year death-censored graft survival, with a death-censored graft survival in recipients of a kidney with a KDPI <85% of 71.0% (95% CI, 70.5%-71.5%), 70.5% (95% CI, 69.9%-71.0%), 69.6% (95% CI, 68.7%-70.4%), 65.5% (95% CI, 63.7%-67.3%), and 67.2% (95% CI, 64.6%-69.6%), compared to 53.5% (95% CI, 51.1%-55.8%), 50.7% (95% CI, 48.3%-53.1%), 50.3% (95% CI, 46.6%-53.8%), 50.7% (95% CI, 45.1%-56.1%), and 48.3% (95% CI, 40.0%-56.1%), for recipients of a kidney with a KDPI >85%.

Limitations

Heterogeneity of acceptance patterns among transplant centers, presence of confounding variables leading to acceptance of kidneys with prolonged cold ischemia times.

Conclusions

Cold ischemia time was associated with an increased risk of delayed graft function and primary nonfunction. However, the effect of increased cold ischemia time is modest and has less impact than the KDPI. Transplant programs should not consider prolonged cold ischemia time alone as a predominant reason to decline an organ, especially with a KDPI <85%.

Incidence, predictors, and outcomes of early hospital readmissions after kidney transplantation: Systemic review and meta-analysis

BACKGROUND

Early hospital readmission (EHR) within 30 days after kidney transplantation is a significant quality indicator of transplant centers and patient care. This meta-analysis aims to evaluate the incidence, predictors, and outcomes of EHR after kidney transplantation.

METHODS

We comprehensively searched the databases, including PubMed, Cochrane CENTRAL, and Embase, from inception until December 2021 to identify studies that assessed incidence, risk factors, and outcome of EHR. The outcomes included death-censored graft failure and mortality. Data from each study were combined using the random effect to calculate the pooled incidence, mean difference (MD), odds ratio (OR), and hazard ratio (HR) with 95% confidence interval (CI).

RESULTS

A total of 17 studies were included. The pooled EHR incidence after kidney transplant was 24.4% (95% CI 21.7-27.3). Meta-analysis showed that recipient characteristics, including older recipient age (MD 2.05; 95% CI 0.90-3.20), Black race (OR 1.31; 95% CI 1.11, 1.55), diabetes (OR 1.32; 95% CI 1.22-1.43), and longer dialysis duration (MD 0.85; 95% CI 0.41, 1.29), donor characteristics, including older donor age (MD 2.02; 95% CI 0.93-3.11), and transplant characteristics, including delayed graft function (OR 1.75; 95% CI 1.42-2.16) and longer length of hospital stay during transplantation (MD 1.93; 95% CI 0.59-3.27), were significantly associated with the increased risk of EHR. EHR was significantly associated with the increased risk of death-censored graft failure (HR 1.70; 95% CI 1.43-2.02) and mortality (HR 1.46; 95% CI 1.27-1.67) within the first year after transplantation.

CONCLUSION

Almost one-fourth of kidney transplant recipients had EHR within 30 days after transplant, and they had worse post-transplant outcomes. Several risk factors for EHR were identified. This calls for future research to develop and implement for management strategies to reduce EHR in high-risk patients.

The Current State of Donor-Derived Cell-Free DNA Use in Allograft Monitoring in Kidney Transplantation

Renal transplantation is the definitive therapy for patients suffering from end-stage renal disease. Though there have been significant advances in immunosuppression in these patients, there is still up to 30% acute and subclinical rejection. Current standards employ lab markers of renal function and biopsy results for accurate diagnosis. However, donor derived cell-free DNA has been identified as a measurable lab test that may be able to adequately diagnose rejection at early stages, precluding the need for invasive procedures like biopsy. We obtained published data directly from companies that offer ddcfDNA assay tests and additionally conducted a literature review using databases like PUBMED and NIH U.S. National Library of Medicine. We comprehensively compare the most used ddcfDNA assays, delineate their respective limitations, and further explore future directions in the utility of ddcfDNA in renal transplant patients.

COVID-19 Infection and Response to Vaccination in Chronic Kidney Disease and Renal Transplantation: A Brief Presentation

Chronic kidney disease (CKD) is associated with phenotypic and functional changes in the immune system, followed by detrimental clinical consequences, such as severe infections and defective response to vaccination. Two years of the pandemic, due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have undoubtedly changed the world; however, all efforts to confront infection and provide new generation vaccines tremendously improved our understanding of the mechanisms of the immune response against infections and after vaccination. Humoral and cellular responses to vaccines, including mRNA vaccines, are apparently affected in CKD patients, as elimination of recent thymic emigrant and naïve lymphocytes and regulatory T-cells, together with contraction of T-cell repertoire and homeostatic proliferation rate, which characterized CKD patients are responsible for impaired immune activation. Successful renal transplantation will restore some of these changes, although several epigenetic changes are irreversible and even accelerated by the induction of immunosuppression. Response to vaccination is definitely impaired among both CKD and RT patients. In the present review, we analyzed the differences in immune response after vaccination between these patients and healthy individuals and depicted specific parameters, such as alterations in the immune system, predisposing to this deficient response.

Donor Derived Cell Free DNA in Kidney Transplantation: The Circa 2020–2021 Update

The routine surveillance of kidney transplant allografts has relied on imperfect non-invasive biomarkers such as creatinine and urinary indices, while the gold standard allograft biopsy is associated with risk of bleeding, organ injury and sampling errors. Donor derived cell free DNA (dd-cfDNA) is being employed as a biomarker that addresses limitations of these surveillance methods, albeit has inherent drawbacks. This review provides an update on the enhanced understanding of dd-cfDNA and its expanded use beyond the conventional indication of detecting allograft rejection.

Vaccine Response in the Immunocompromised Patient with Focus on Cellular Immunity

During the last few years, we have experienced a shift in how we evaluate the effectiveness of vaccines [...]

Correlation of Fc Receptor Polymorphisms with Pneumococcal Antibodies in Vaccinated Kidney Transplant Recipients

Several polymorphisms within Fc receptors (FCR) have been described, some of which correlate with allograft function. In the current study, we determined three Fcγ receptor and five Fcα receptor dimorphisms in 47 kidney transplant recipients who had been vaccinated against Streptococcus pneumoniae. We analyzed if FCR genotypes correlated with pneumococcal antibodies and their serotype-specific opsonophagocytic function, tested prior to and at months 1 and 12 post-vaccination. In parallel, we assessed antibodies against HLA and MICA and determined kidney function. We observed that IgG2 antibodies against pneumococci at months 1 and 12 after vaccination and IgA antibodies at month 1 differed significantly between the carriers of the three genotypes of FCGR3A rs396991 (V158F, p = 0.02; 0.04 and 0.009, respectively). Moreover, the genotype of FCGR3A correlated with serotype-specific opsonophagocytic function, reaching statistical significance (p < 0.05) at month 1 for 9/13 serotypes and at month 12 for 6/13 serotypes. Heterozygotes for FCGR3A had the lowest antibody response after pneumococcal vaccination. On the contrary, heterozygotes tended to have more antibodies against HLA class I and impaired kidney function. Taken together, our current data indicate that heterozygosity for FCGR3A may be unfavorable in kidney transplant recipients.

Beyond Graft Survivl: A National Cohort Study Quantifying the Impact of Increasing Kidney Donor Profile Index on Recipient Outcomes 1 Year Post-transplantation

Background.

The reporting of a locally validated kidney donor profile index (KDPI) began in Australia in 2016. Across diverse populations, KDPI has demonstrated utility in predicting allograft survival and function. A metric that incorporates both elements may provide a more comprehensive picture of suboptimal recipient outcomes.

Methods.

A retrospective cohort study of adult kidney transplant recipients in Australia (January 2009 to December 2014) was conducted. Conventional recipient outcomes and a composite measure of suboptimal outcome (1-y allograft failure or estimated glomerular filtration rate [eGFR] <30 mL/min) were evaluated across KDPI intervals (KDPI quintiles and 5-point increments in the KDPI 81–100 cohort). The impact of increasing KDPI on allograft function (1-y eGFR) and a suboptimal outcome was explored using multivariable regression models, adjusting for potential confounding factors.

Results.

In 2923 donor kidneys eligible for analysis, median KDPI was 54 (interquartile range [IQR], 31–77), and Kidney Donor Risk Index was 1.39 (IQR, 1.03–1.67). The median 1-y eGFR was 52.74 mL/min (IQR, 40.79–66.41 mL/min). Compared with the first quintile reference group, progressive reductions in eGFR were observed with increasing KDPI and were maximal in the fifth quintile (adjusted β-coefficient: −27.43 mL/min; 95% confidence interval, –29.44 to –25.42; P < 0.001). A suboptimal outcome was observed in 359 recipients (12.3%). The adjusted odds for this outcome increased across quintiles from a baseline of odds ratio of 1.00 (first quintile) to odds ratio of 11.68 (95% confidence interval, 6.33-21.54, P < 0.001) in the fifth quintile cohort.

Conclusions.

Increases in donor KDPI were associated with higher probabilities of a suboptimal outcome and poorer baseline allograft function, particularly in the KDPI > 80 cohort. These findings may inform pretransplant discussions with potential recipients of high-KDPI allografts.

Plasma Donor-Derived Cell-Free DNA Levels Are Associated With the Inflammatory Burden and Macrophage Extracellular Trap Activity in Renal Allografts

Recent studies have confirmed the role of plasma donor-derived cell-free DNA (ddcfDNA) as a reliable non-invasive biomarker for allograft injury after kidney transplantation. Whereas the variability of plasma ddcfDNA levels among recipients has limited their clinical use. This study aimed to explore the intrinsic factors associated with plasma ddcfDNA elevation by investigating the impact of Banff lesions and inflammatory infiltrates on ddcfDNA levels in kidney transplant recipients. From March 2017 to September 2019, a total of 106 kidney transplant recipients with matched allograft biopsies were included, consisting of 13 recipients with normal/nonspecific changes, 13 recipients with borderline changes, 60 with T cell-mediated rejection, and 20 with antibody-mediated rejection. Histologic classification was performed according to the Banff 2017 criteria by two experienced pathologists. Plasma ddcfDNA fractions ranged from 0.12% to 10.22%, with a median level of 0.91%. Banff histology subelements including glomerulitis, intimal arteritis, and severe interstitial inflammation were correlated with increased plasma ddcfDNA levels. The inflammatory cell infiltrate in the allografts was phenotyped by immunochemistry and automatically counted by digital image recognition. Pearson correlation analysis revealed a significant positive correlation between macrophage infiltrations in allografts and plasma ddcfDNA levels. Additionally, macrophage extracellular trap (MET) activity was significantly associated with the rise in plasma ddcfDNA levels. Our findings demonstrated that plasma ddcfDNA could reflect the inflammatory state in renal allografts and suggested the potential role of METs in the pathogenesis of allograft injury.

The type of SARS-CoV-2 vaccine influences serological response in kidney transplant recipients

Vaccination is a promising strategy to control the ongoing pandemic; however, solid organ recipients tend to develop a weaker immune response to vaccination. Anti-spike SARS-CoV-2 antibodies titers were measured 2-4 weeks post-vaccination completion in 131 KT patients without previous infection. Demographic, clinical, and laboratorial parameters were analyzed to identify which factors contributed to seroconversion. Factors that influenced seroconversion, that occurred in 76 patients (58%), were longer time post-transplant, immunosuppression without an antiproliferative drug and vaccination with mRNA vaccines. Patients who received mRNA vaccines had significantly higher rates of seroconversion compared with adenovirus vector vaccines (67% vs 33%, P < .001) and higher anti-spike IgG titers. These findings reinforce the need to discuss the vaccination strategy in this population, including a third dose with a mRNA vaccine.

Cell-free DNA as a solid-organ transplant biomarker: technologies and approaches

High-quality biomarkers that detect emergent graft damage and/or rejection after solid-organ transplantation offer new opportunities to improve post-transplant monitoring, allow early therapeutic intervention and facilitate personalized patient management. Donor-derived cell-free DNA (DD-cfDNA) is a particularly exciting minimally invasive biomarker because it has the potential to be quantitative, time-sensitive and cost-effective. Increased DD-cfDNA has been associated with graft damage and rejection episodes. Efforts are underway to further improve sensitivity and specificity. This review summarizes the procedures used to process and detect DD-cfDNA, measurement of DD-cfDNA in clinical transplantation, approaches for improving sensitivity and specificity and long-term prospects as a transplant biomarker to supplement traditional organ monitoring and invasive biopsies.

Donor Death Category Is an Effect Modifier Between Cold Ischemia Time and Post-transplant Graft Function in Deceased-Donor Kidney Transplant Recipients

Objectives: We aimed to analyze the effect of cold ischemia time (CIT) on post-transplant graft function through mixed-effect model analysis to reduce the bias caused by paired mate kidneys.

Methods: We reviewed all kidney transplantation records from 2015 to 2019 at our center. After applying the exclusion criteria, 561 cases were included for analysis. All donor characteristics, preservation and matching information, and recipient characteristics were collected. Transplant outcomes included delayed graft function (DGF) and estimated glomerular filtration rate (eGFR). Generalized linear mixed models were applied for analysis. We also explored potential effect modifiers, namely, donor death category, expanded criteria donors, and donor death causes.

Results: Among the 561 cases, 79 DGF recipients developed DGF, and 15 recipients who died after surgery were excluded from the eGFR estimation. The median stable eGFR of the 546 recipients was 60.39 (47.63, 76.97) ml/min/1.73 m². After adjusting for confounding covariates, CIT had a negative impact on DGF incidence [odds ratio = 1.149 (1.006, 1.313), P = 0.041]. In the evaluation of the impact on eGFR, the regression showed that CIT had no significant correlation with eGFR [β = −0.287 (−0.625, 0.051), P = 0.096]. When exploring potential effect modifiers, only the death category showed a significant interaction with CIT in the effect on eGFR (P_interaction = 0.027). In the donation after brain death (DBD) group, CIT had no significant effect on eGFR [β = 0.135 (−0.433, 0.702), P = 0.642]. In the donation after circulatory death/donation after brain death followed by circulatory death (DCD/DBCD) group, CIT had a significantly negative effect on eGFR [β= −0.700 (−1.196, −0.204), P = 0.006]. Compared to a CIT of 0–6 h, a CIT of 6–8 or 8–12 h did not decrease the post-transplant eGFR. CIT over 12 h (12–16 h or over 16 h) significantly decreased eGFR. With the increase in CIT, the regenerated eGFR worsened (P_trend = 0.011).

Conclusion: Considering the effect of paired mate kidneys, the risk of DGF increased with prolonged CIT. The donor death category was an effect modifier between CIT and eGFR. Prolonged CIT did not reduce the eGFR level in recipients from DBDs but significantly decreased the eGFR in recipients from DCDs/DBCDs. This result indicates the potential biological interaction between CIT and donor death category.

Establishment of an ELISpot Assay to Detect Cellular Immunity against S. pneumoniae in Vaccinated Kidney Transplant Recipients

In organ transplant recipients, the rate of invasive pneumococcal diseases is 25 times greater than in the general population. Vaccination against S. pneumoniae is recommended in this cohort because it reduces the incidence of this severe form of pneumococcal infection. Previous studies indicate that transplant recipients can produce specific antibodies after pneumococcal vaccination. However, it remains unclear if vaccination also induces specific cellular immunity. In the current study on 38 kidney transplant recipients, we established an interferon-γ ELISpot assay that can detect serotype-specific cellular responses against S. pneumoniae. The results indicate that sequential vaccination with the conjugated vaccine Prevenar 13 and the polysaccharide vaccine Pneumovax 23 led to an increase of serotype-specific cellular immunity. We observed the strongest responses against the serotypes 9N and 14, which are both components of Pneumovax 23. Cellular responses against S. pneumoniae correlated positively with specific IgG antibodies (r = 0.32, p = 0.12). In conclusion, this is the first report indicating that kidney transplant recipients can mount specific cellular responses after pneumococcal vaccination. The ELISpot we established will allow for further investigations. These could help to define, for example, factors influencing specific cellular immunity in immunocompromised cohorts or the duration of cellular immunity after vaccination.

Emerging role of cell-free DNA in kidney transplantation

Monitoring kidney transplants for rejection conventionally includes serum creatinine, immunosuppressive drug levels, proteinuria, and donor-specific antibody (DSA). Serum creatinine is a late marker of allograft injury, and the predictive ability of DSA regarding risk of rejection is variable. Histological analysis of an allograft biopsy is the standard method for diagnosing rejection but is invasive, inconvenient, and carries risk of complications. There has been a long quest to find a perfect biomarker that noninvasively predicts tissue injury caused by rejection at an early stage, so that diagnosis and treatment could be pursued without delay in order to minimize irreversible damage to the allograft. In this review, we discuss relatively novel research on identifying biomarkers of tissue injury, specifically elaborating on donor-derived cell-free DNA, and its clinical utility.

Case Report: Mini-endoscopic combined intrarenal surgery in an en-bloc kidney transplant

Background

Overall incidence of stones in kidney transplant recipients is 1%. En-bloc kidney transplant is a rare anatomical condition in which kidney stones treatment can be extremely difficult to treat. As far as we know, no cases of staghorn calculi in en-bloc kidney transplant have been published so far.

Case presentation

A 27-year-old woman presented to the Emergency Department because of asthenia, adynamia and weight loss associated with lower urinary tract symptoms and subfebrile temperature. Ten years before, she had undergone an en-bloc kidney transplant because of end-stage renal disease secondary to perinatal asphyxia syndrome. One kidney was implanted capo-volta in the right iliac fossa and the other one in the right flank. NCCT scan showed incomplete staghorn calculi in the iliac fossa transplanted kidney. Besides, severe dilation of the native and the right flank transplanted kidney, due to two ureteral stones of 6 and 7 mm impacted in the uretero-ureteral anastomosis, was found. After hospital admission and under ceftriaxone prophylaxis, an attempt to perform primary RIRS following our COVID protocol was carried out. Nevertheless, we ended up placing a JJ stent because once the guidewire passed through the ureteral stones, purulent material came out from the ureteral orifice. She stayed 9 days in-hospital for management of postobstructive polyuria and was discharged with oral antibiotics. Three weeks afterward, we removed the stent and performed flexible ureteroscopy and holmium laser lithotripsy of the ureteral stones. In the same procedure, we performed Mini-ECIRS (21 French) previous ultrasound-guided upper pole puncture. Postoperative NCCT scan showed neither residual fragments nor operative complications.

Conclusion

This is the first clinical case reporting Mini-ECIRS in a patient with an en-bloc kidney transplant. This endourological approach seems to be a feasible, safe and effective approach to treat stones in this anatomically challenging condition.

Management of the Failing Kidney Transplant: Challenges and Solutions

The kidneys are the most transplanted organs, and the number of failed kidney transplants that require reinstitution of renal replacement therapy in patients is on the increase. Increased mortality has been noted in patients with failed grafts compared with transplant- naïve patients with chronic kidney disease who are treated with dialysis. Issues such as management of immunosuppression, the need for transplant nephrectomy, addressing the increased risk of cardiovascular events, malignancies, and infections are debatable and often based on individual or hospital practices. The optimal timing and modality of renal replacement therapy to be reinitiated are sometimes blurred, with considerable variations among physician practices. Guidelines are therefore needed to appropriately manage this special population of patients with the aim of improving outcomes. Here, our objective was to review the current practices in managing patients with failing kidney transplants so that recommendations can be made based on the available evidence.