Allosensitization after transplant failure: the role of graft nephrectomy and immunosuppression - a retrospective study

Clinical relevance of HLA-DQ eplet mismatch and maintenance immunosuppression with risk of allosensitization after kidney transplant failure

The optimal immunosuppression management in patients with a failed kidney transplant remains uncertain. This study analyzed the association of class II HLA eplet mismatches and maintenance immunosuppression with allosensitization after graft failure in a well characterized cohort of 21 patients who failed a first kidney transplant. A clinically meaningful increase in cPRA in this study was defined as the cPRA that resulted in 50% reduction in the compatible donor pool measured from the time of transplant failure until the time of repeat transplantation, death, or end of study. The median cPRA at the time of failure was 12.13% (interquartile ranges = 0.00%, 83.72%) which increased to 62.76% (IQR = 4.34%, 99.18%) during the median follow-up of 27 (IQR = 18, 39) months. High HLA-DQ eplet mismatches were significantly associated with an increased risk of developing a clinically meaningful increase in cPRA (p = 0.02) and de novo DQ donor-specific antibody against the failed allograft (p = 0.02). We did not observe these associations in patients with high HLA-DR eplet mismatches. Most of the patients (88%) with a clinically meaningful increase in cPRA had both a high DQ eplet mismatch and a reduction in their immunosuppression, suggesting the association is modified by immunosuppression. The findings suggest HLA-DQ eplet mismatch analysis may serve as a useful tool to guide future clinical studies and trials which assess the management of immunosuppression in transplant failure patients who are repeat transplant candidates.

Routine screening for HLA Antibodies in Heart Transplant patients-Does it affect clinical decision making?

BACKGROUND

We aimed to assess outcomes in patients with and without donor specific antibodies (DSA) and to evaluate the relationship between DSA presence and graft function, cardiac allograft vasculopathy (CAV), and mortality.

METHODS

The study population comprises 193 consecutive long-term heart transplanted (HTx) patients who underwent DSA surveillance between 2016 and 2022. The patients were prospectively screened for CAV through serial coronary angiograms, graft function impairment through serial echocardiograms, and cardiac biomarkers. The patients were followed from the first DSA measurement until death, 5 years follow-up or right censuring on the 30th of June 2023.

RESULTS

DSAs were detected in 50 patients using a cut-off at MFI ≥1000 and 45 patients using a cut-off at ≥2000 MFI. The median time since HTx was 9.0 years [3.0-14.4]. DSA positive patients had poorer graft function and higher values of NT-proBNP and troponin T, and more prevalent CAV than DSA negative patients. In total, 25 patients underwent endomyocardial biopsies due to DSA presence while another eight patients underwent endomyocardial biopsies for other reasons. Histological antibody mediated rejection (AMR) signs were seen in three biopsies. During a median follow-up of five years [4.7-5], a total of 41 patients died. Mortality rates did not differ between DSA positive and DSA negative patients (HR 1.2, 95% CI .6-2.4). DSA positive patients were more likely to experience CAV progression than DSA negative patients (HR 2.7, 95% CI 1.5-4.8) CONCLUSIONS: Routine screening reveals DSA in approximately 25% of long-term HTx patients but is rarely related to histopathological AMR signs. DSA presence was associated with poorer graft function and more prevalent and progressive CAV. However, DSA positive patients had similar survival rates to DSA negative patients.

Evolution of HLA-sensitization according to immunosuppressive therapy management among kidney transplant patients returning to dialysis between 2008 and 2019: A French retrospective study

BACKGROUND

The optimal management of immunosuppressive therapy (IT) after kidney allograft failure (KAF) remains controversial. Although maintaining IT may reduce HLA-sensitization and improve access to retransplantation, it may also increase the rate of immunosuppression-related complications. The overall impact on patient mortality is unknown. The main objective of this study was to compare the evolution of HLA-sensitization 6 months after KAF according to IT management.

METHODS

Individual clinical and health care data were extracted from the French national end-stage kidney disease registry (Renal Epidemiology and Information Network [REIN]) and the French National Health Data system (SNDS), respectively. Patients aged > 18 years returning to dialysis after KAF between January 2008 and December 2019 in Lorraine were included. Patients were classified into two groups, IT continuation or IT discontinuation. HLA-sensitization was defined as an increase in incompatible graft rate (IGR) between KAF and 6 months post-KAF (change to a higher predefined category (0%-5%), (5%-20%), (20%-50%), (50%-85%), (85%-95%), (95%-98%), (98%-100%)). Secondary outcome was patient survival according to IT management.

RESULTS

A total of 121 patients were included, 35 (29%) of whom continued IT. HLA-sensitization after KAF tended to be higher in the "IT discontinuation" group (57% vs. 38% in the "IT continuation" group, p = .07). In multivariate analysis, IT continuation was associated with a lower increase in IGR (OR .37, 95% CI [.14; .93]). IT management was not associated with patient mortality.

CONCLUSIONS

Continuation of IT after KAF was associated with less change in IGR and was not associated with excess mortality.

The Role of Allograft Nephrectomy in the Failing Kidney Transplant

Patients with failed renal allografts have associated increased morbidity and mortality. The individualization of immunosuppression taper is the key element in managing these patients to avoid graft intolerance and sensitization while balancing the risk of continued immunosuppression. Most patients with uncomplicated chronic allograft failure do not require allograft nephrectomy (AN), and there is no clear evidence that it improves outcomes. The AN procedure is associated with variable morbidity and mortality. It is reserved mainly for early technical graft failure or in symptomatic cases associated with allograft infection, malignancy, or graft intolerance syndrome. It may also be considered in those who cannot tolerate immunosuppression and are at high risk for graft intolerance. AN has been associated with an increased risk of sensitization due to inflammatory response from surgery, immunosuppression withdrawal with allograft failure, and retained endovascular tissue. Although it is presumed that for-cause AN after transplant failure is associated with sensitization, it remains unclear whether elective AN in patients who remain on immunotherapy may prevent sensitization. The current practice of immunosuppression taper has not been shown to prevent sensitization or increase infection risk, but current literature is limited by selection bias and the absence of medication adherence data. We discuss the management of failed allografts based on retransplant candidacy, wait times, risk of graft intolerance syndrome, and immunosuppression side effects. Many unanswered questions remain, and future prospective randomized trials are needed to help guide evidence-based management.

Impact of Calcineurin Inhibitor-Based Immunosuppression Maintenance During the Dialysis Period After Kidney Transplant Failure on the Next Kidney Graft Outcome: A Retrospective Multicenter Study With Propensity Score Analysis

The impact of immunosuppressive therapy (IS) strategies after kidney transplant failure (KTF) on potential future new grafts is poorly established. We assessed the potential benefit of calcineurin inhibitor (CNI)-based IS maintenance throughout the dialysis period on the outcome of the second kidney transplant (KT). We identified 407 patients who underwent a second KT between January 2008 and December 2018 at four French KT centers. Inverse probability of treatment weighting was used to control for potential confounding. We included 205 patients with similar baseline characteristics at KTF: a total of 53 received at least CNIs on the retransplant day (G-CNI), and 152 did not receive any IS (G-STOP). On the retransplant date, G-STOP patients experienced a longer pretransplant dialysis time, were more often hyperimmunized, and underwent more expanded-criteria donor KTs than G-CNI patients. During the second KT follow-up period, rejection episodes were similar in both groups. The 10-year survival rates without death and dialysis were 98.7% and 59.5% in G-CNI and G-STOP patients, respectively. In the multivariable analysis, CNI-based IS maintenance was associated with better survival (hazard ratio: 0.08; 95% confidence interval: 0.01-0.58, p = 0.01). CNI-based IS maintenance throughout the dialysis period after KTF may improve retransplantation outcomes.

Continuation of immunosuppression vs. immunosuppression weaning in potential repeat kidney transplant candidates: a care management perspective

Management of immunosuppression in patients with a failing or failed kidney transplant requires a complete assessment of their clinical condition. One of the major considerations in determining immunosuppression is whether or not such an individual is considered a candidate for re-transplantation. Withdrawal of immunosuppression in a re-transplant candidate can result in allosensitization and markedly reduce the chances of a repeat transplant. In this review, we summarize the effects of immunosuppression reduction on HLA sensitization, discuss the impacts of allosensitization in these patients, and explore reduction protocols and future directions. Risks of chronic immunosuppression, medical management of the failing allograft, and the effect of nephrectomy are covered elsewhere in this issue.

Revisiting maintenance immunosuppression in patients with renal transplant failure: early weaning of immunosuppression versus prolonged maintenance-systematic review and meta-analysis

INTRODUCTION

Prolonged immunosuppression after dialysis start has been assumed to reduce sensitization, need for graft nephrectomy, and to favor re-transplantation. In contrast, immunosuppression is considered to increase the risk of mortality, infection, and malignancy. We aimed to assess the evidence regarding superiority of early or late withdrawal of maintenance immunosuppression post renal transplant failure.

METHODS

A literature search of the PubMed, WOS, Ovid, and Scopus databases was conducted. Combined relative risks, (RRs), mean differences, and 95% confidence intervals (CIs) were calculated by using a random-effect model.

RESULTS

Ten studies involving 1187 patients with kidney transplant failure were included. No difference could be detected between patients with early withdrawal of  immunosuppressive drugs (≤ 3 months) or prolonged immunosuppressive treatment (> 3 months) regarding mortality (95% CI 0.91-2.28), panel reactive antibodies (PRAs) (95% CI - 0.75-30.10), re-transplantation rate (95% CI 0.55-1.35), infectious episodes (95% CI 0.67, 1.17), cancer (95% CI 0.26-1.54), and graft nephrectomy (95% CI 0.82-1.63). Similarly, no difference was found between immunosuppressive drug withdrawal over < 6 or ≥ 6 months regarding mortality (95% CI 0.16, 2.89), re-transplantation rate (95% CI 0.85-1.55), cancer (95% CI 0.37-1.63), and allograft nephrectomy (95% CI 0.87-4.33).

CONCLUSION

Prolonged maintenance immunosuppression post kidney transplant failure is not associated with increased risk of mortality, infection, or malignancy, or reduced risk of sensitization or allograft nephrectomy compared with early withdrawal.

Immunosuppression in Uterus Transplantation: Experience From the Dallas Uterus Transplant Study

BACKGROUND

Uterus transplantation is a temporary transplant allowing women with absolute uterine factor infertility to experience pregnancy and childbirth. The degree of immunosuppression (IS) required to prevent rejection while minimizing toxicity to the recipient and fetus remains an area of investigation.

METHODS

In this article, we describe immunosuppressive therapy, rejection episodes, infections, and adverse events in 14 uterus transplant recipients. Induction consisted of antithymocyte globulin and methylprednisolone. Ten recipients (71%) received no steroids postoperatively, and 4 (29%) had steroids tapered off at 42 d. All received oral tacrolimus, either immediate release (n = 2, 14%) or extended release (n = 12, 86%). Mycophenolate was used in 4 cases (29%), de novo azathioprine in 9 (64%), and de novo everolimus in 1 (7%).

RESULTS

Sixteen clinically silent, treatment-responsive rejection episodes occurred in 10 recipients. Five recipients (36%) experienced acute kidney injury. In 3 recipients, IS was discontinued due to renal dysfunction. Eleven infection episodes were noted in 7 recipients. No babies had congenital abnormalities.

CONCLUSIONS

Our experience demonstrates that safe IS regimens can be used for uterus transplant recipients before and during pregnancy.

Assessment and management of allosensitization following heart transplant in adults

Immunological injury to the allograft, specifically by antibodies to de novo donor specific human leukocyte antigen (dnDSA) and antibody mediated injury and rejection are the major limitations to graft survival after heart transplantation (HT). As such, our approach to allosensitization remains limited by the inability of contemporaneous immunoassays to unravel pathogenic potential of dnDSA. Additionally, the role of dnDSA is continuously evaluated with emerging methods to detect rejection. Moreover, the timing and frequency of dnDSA monitoring for early detection and risk mitigation as well as management of dnDSA remain challenging. A strategic approach to dnDSA employs diagnostic assays to determine relevant antibodies in conjunction with clinical presentation and injury/rejection of allograft to tailor therapeutics. In this review, we aim to outline contemporary knowledge involving detection, monitoring and management of dnDSA after HT. Subsequently, we propose a diagnostic and therapeutic approach that may mitigate morbidity and mortality while balancing adverse reactions from pharmacotherapy.

Challenges in the Management of the Patient with a Failing Kidney Graft: A Narrative Review

Patients with a failed kidney allograft have steadily increase in recent years and returning to dialysis after graft loss is one of the most difficult transitions for chronic kidney disease patients and their assistant physicians. The management of these patients is complex and encompasses the treatment of chronic kidney disease complications, dialysis restart and access planning, immunosuppression withdrawal, graft nephrectomy, and evaluation for a potential retransplant. In recent years, several groups have focused on the management of the patient with a failing renal graft and expert recommendations are arising. A review of Pubmed, ScienceDirect and the Cochrane Library was performed focusing on the specific care of these patients, from the management of low clearance complications to concerns with a subsequent kidney transplant. Conclusion: There is a growing interest in the failing renal graft and new approaches to improve these patients’ outcomes are being defined including specific multidisciplinary programs, individualized immunosuppression withdrawal schemes, and strategies to prevent HLA sensitization and increase retransplant rates.

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.

Transplant Nephrectomy: Current Concepts

Kidney transplantation is the gold standard treatment option for patients with endstage kidney disease. As the number of waitlisted patients increases, the gap between supply and demand for suitable donor kidneys keeps widening. The adoption of novel strategies that expand the donor pool has attenuated this issue to a certain degree, and this has led to a progressive increase in the number of annual transplants performed. As transplanted kidneys have a finite lifespan, there is a reciprocal rise in the number of patients who return to dialysis once their allograft fails. The clinicians involved in the management of such patients are left with the problem of managing the nonfunctioning allograft. The decision to undertake transplant nephrectomy (TN) in these patients is not straightforward. Allograft nephrectomy is a procedure that is associated with significant morbidity and mortality. It will have implications for the outcomes of the subsequent transplant. In this review, we aimed to compressively discuss the indications, techniques, and outcomes of TN, which is an integral component of the management of a failing allograft.

How to Deal With Kidney Retransplantation-Second, Third, Fourth, and Beyond

Kidney transplantation is the best health option for patients with end-stage kidney disease. Ideally, a kidney transplant would last for the lifetime of each recipient. However, depending on the age of the recipient and details of the kidney transplant, there may be a need for a second, third, fourth, or even more kidney transplants. In this overview, the outcome of multiple kidney transplants for an individual is presented. Key issues include surgical approach and immunologic concerns. Included in the surgical approach is an analysis of transplant nephrectomy, with indications, timing, and immunologic impact. Allograft thrombosis, whether related to donor or recipient factors merits investigation to prevent it from happening again. Other posttransplant events such as rejection, viral illness (polyomavirus hominis type I), recurrent disease (focal segmental glomerulosclerosis), and posttransplant lymphoproliferative disease may lead to the need for retransplantation. The pediatric recipient is especially likely to need a subsequent kidney transplant. Finally, noncompliance/nonadherence can affect both adults and children. Innovative approaches may reduce the need for retransplantation in the future.

Immunosuppressant Medication Use in Patients with Kidney Allograft Failure: A Prospective Multi-Center Canadian Cohort Study

Background: Patients with kidney transplant failure have a high risk of hospitalization and death due to infection. The optimal use of immunosuppressants after transplant failure remains uncertain and clinical practice varies widely. Methods: This prospective cohort study enrolled patients within 21 days of starting dialysis after transplant failure in 16 Canadian centers. Immunosuppressant medication use, death, hospitalized infection, rejection of the failed allograft, and panel reactive anti-HLA antibodies (PRA) were determined at 1, 3, 6 , and 12 months and bi-annually until death, repeat transplantation, or loss to follow-up. Results: The 269 study patients were followed for a median of 558 days. There were 33 deaths, 143 patients hospitalized for infection, and 21 rejections. Most patients (65%) continued immunosuppressants, 20% continued prednisone only, while 15% discontinued all immunosuppressants. In multivariable models, patients who continued immunosuppressants had a lower risk of death (HR =0.40, 95% CI, 0.17-0.93) and were not at increased risk of hospitalized infection (HR 1.81; 95% CI 0.82 to 4.0) compared to patients who discontinued all immunosuppressants or continued prednisone only. The mean class I and class II PRA increased from 11% to 27% and 25% to 47%, respectively, but did not differ by immunosuppressant use. Continuation of immunosuppressants was not protective of rejection of the failed allograft (HR 0.81, 95% CI, 0.22-2.94). Conclusions: Prolonged use of immunosuppressants greater than one year after transplant failure was not associated with a higher risk of death or hospitalized infection but was insufficient to prevent higher anti-HLA antibodies or rejection of the failed allograft.

Association of Nephrectomy of the Failed Renal Allograft With Outcome of the Future Transplant: A Systematic Review

Kidney allograft failure is a significant complication in kidney transplant recipients, and the surgical decision to perform allograft nephrectomy poses a strong dilemma because it is associated with significant morbidity and mortality. There is a debate over the effect of allograft nephrectomy on the development of allosensitization and the impact on potential retransplantation. Moreover, the use of immunosuppression may contribute to antibody allosensitization as allograft nephrectomy and immunosuppression act jointly and interdependently toward antibody formation. Because more and more patients with kidney allograft failure are entering wait lists for repeat transplant procedures, a review of available evidence on the field is required. Here, we performed a literature search using multiple medical databases to identify relevant studies that assessed the effects of allograft nephrectomy on important retransplant endpoints such as allograft and patient survival; furthermore, secondary outcomes such as alloantibody sensitization were also evaluated. A total of 15 studies were identified; all were retrospective, single-center studies. The rate of allograft nephrectomy in patients with retransplant varied widely (from 20% to 80%). The average allograft nephrectomy rate in included studies was 43% (allograft nephrectomy number/number of repeat transplantations: 2351/5431). Most studies did not observe an allograft survival benefit after retransplant for patients with allograft nephrectomy with the exception of 4 studies that found worse allograft survival after allograft nephrectomy. Interestingly, 1 study found that, in the patient subgroup with early kidney allograft failure (<12 months posttransplant), allograft nephrectomy may be associated with better allograft survival. Available data suggested that allograft nephrectomy may be associated with a higher risk of increasing anti-HLA antibody levels. The quality of the included studies suffered from nonrandomized design, potential confounding, and small sample size. To conclude, further randomized controlled trials are required to delineate the role of allograft nephrectomy on retransplant outcomes.

Kidney re-transplantation after living donor graft nephrectomy due to de novo chromophobe renal cell carcinoma: A case report

BACKGROUND

There are few reported cases of allograft nephrectomy due to malignancy followed by successful renal re-transplantation two years later. In this paper, we report a patient who underwent kidney re-transplantation after living donor graft nephrectomy due to de novo chromophobe renal cell carcinoma (ChRCC) involving the allograft kidney.

CASE SUMMARY

A 34-year-old man underwent living kidney transplantation at the age of 22 years for end-stage renal disease. Maintenance immunosuppression consisted of tacrolimus, mycophenolate mofetil (MMF), and prednisone. Six years post-transplantation, at another hospital, ultrasonography revealed a small mass involving the upper pole of the graft. The patient declined further examination and treatment at this point. Seven years and three months post-transplantation, the patient experienced decreasing appetite, weight loss, gross hematuria, fatigue, and oliguria. Laboratory tests showed anemia (hemoglobin level was 53 g/L). Contrast-enhanced computed tomography revealed a large heterogeneous cystic-solid mass involving the upper pole of the renal allograft. Graft nephrectomy was performed and immunosuppressants were withdrawn. Histological and immunohistochemical features of the tumor were consistent with ChRCC. One year after allograft nephrectomy, low doses of tacrolimus and MMF were administered for preventing allosensitization. Two years after allograft nephrectomy, the patient underwent kidney re-transplantation. Graft function remained stable with no ChRCC recurrence in more than 2-years of follow-up.

CONCLUSION

De novo ChRCC in kidney graft generally has a good prognosis after graft nephrectomy and withdrawal of immunosuppression. Kidney re-transplantation could be a viable treatment. A 2-year malignancy-free period may be sufficient time before re-transplantation.

What happens after graft loss? A large, long-term, single-center observation

The number of patients returning to dialysis after graft failure increases. Surprisingly, little is known about the clinical and immunological outcomes of this cohort. We retrospectively analyzed 254 patients after kidney allograft loss between 1997 and 2017 and report clinical outcomes such as mortality, relisting, retransplantations, transplant nephrectomies, and immunization status. Of the 254 patients, 49% had died 5 years after graft loss, while 27% were relisted, 14% were on dialysis and not relisted, and only 11% were retransplanted 5 years after graft loss. In the complete observational period, 111/254 (43.7%) patients were relisted. Of these, 72.1% of patients were under 55 years of age at time of graft loss and only 13.5% of patients were ≥65 years. Age at graft loss was associated with relisting in a logistic regression analysis. In the complete observational period, 42 patients (16.5%) were retransplanted. Only 4 of those (9.5%) were ≥65 years at time of graft loss. Nephrectomy had no impact on survival, relisting, or development of dnDSA. Patients after allograft loss have a high overall mortality. Immunization contributes to long waiting times. Only a very limited number of patients are retransplanted especially when ≥65 years at time of graft loss.

Management of Immunosuppression After Kidney Transplant Failure: Effect on Patient Sensitization

BACKGROUND

Immunosuppressive treatment is often interrupted in the first months following kidney transplant failure (KTF) to limit side effects. The aim of this study was to assess the effect of prolonged treatment (PT) of more than 3 months' duration after KTF on HLA sensitization and treatment tolerance.

METHODS

We performed a retrospective observational study involving 119 patients with KTF in 3 French kidney transplant centers between June 2007 and June 2017. Sensitization was defined as the development of HLA donor-specific antibodies (DSA).

RESULTS

In the PT group receiving calcineurin inhibitor (CNI) treatment, 30 of 52 patients (57.7%) were sensitized vs 52 of 67 patients (77.6%) who had early cessation of treatment (P = .02). The results were confirmed by multivariate analysis (odds ratio [OR] = 0.39, 95% confidence interval [CI] [0.16; 0.98], P = .04). The development of de novo DSAs after CNI treatment (n = 63/90 [70.0%]) was significantly more frequent than during CNI treatment, (n = 18/52 [34.6%], P = .01). Panel-reactive antibody ≥85% was lower in the PT group in multivariate analysis (OR = 0.28, 95% CI [0.10; 0.78], P = .02). No differences in the rates of infection, cardiovascular complications, neoplasia, and deaths were observed between the 2 groups. In multivariate analysis, continuation of corticosteroid treatment had no influence on sensitization but was associated with a higher rate of infection (OR = 2.66, 95% CI [1.09; 6.46], P = .03).

CONCLUSION

Maintenance of CNI treatment after return to dialysis in patients requesting a repeat transplant could avoid the development of anti-HLA sensitization with a good tolerance.

Management of patients with a failed kidney transplant: what should we do?

The number of kidney transplant recipients returning to dialysis after graft failure is steadily increasing over time. Patients with a failed kidney transplant have been shown to have a significant increase in mortality compared with patients with a functioning graft or patients initiating dialysis for the first time. Moreover, the risk for infectious complications, cardiovascular disease and malignancy is greater than in the dialysis population due to the frequent maintenance of low-dose immunosuppression, which is required to reduce the risk of allosensitization, particularly in patients with the prospect of retransplantation from a living donor. The management of these patients present several controversial opinions and clinical guidelines are lacking. This article aims to review the leading evidence on the main issues in the management of patients with failed transplant, including the ideal timing and modality of dialysis reinitiation, the indications for an allograft nephrectomy or the correct management of immunosuppression during graft failure. In summary, retransplantation is a feasible option that should be considered in patients with graft failure and may help to minimize the morbidity and mortality risk associated with dialysis reinitiation.

Living Donor Kidney Transplantation Improves Graft and Recipient Survival in Patients with Multiple Kidney Transplants

Background: Failed kidney transplant recipients benefit from a new graft as the general incident dialysis population, although additional challenges in the management of these patients are often limiting the long-term outcomes. Previously failed grafts, a long history of comorbidities, side effects of long-term immunosuppression and previous surgical interventions are common characteristics in the repeated kidney transplantation population, leading to significant complex immunological and technical aspects and often compromising the short- and long-term results. Although recipients’ factors are acknowledged to represent one of the main determinants for graft and patient survival, there is increasing interest in expanding the donor’s pool safely, particularly for high-risk candidates. The role of living kidney donation in this peculiar context of repeated kidney transplantation has not been assessed thoroughly. The aim of the present study is to analyse the effects of a high-quality graft, such as the one retrieved from living kidney donors, in the repeated kidney transplant population context. Methods: Retrospective analysis of the outcomes of the repeated kidney transplant population at our institution from 1968 to 2019. Data were extracted from a prospectively maintained database and stratified according to the number of transplants: 1st, 2nd or 3rd+. The main outcomes were graft and patient survivals, recorded from time of transplant to graft failure (return to dialysis) and censored at patient death with a functioning graft. Duration of renal replacement therapy was expressed as cumulative time per month. A multivariate analysis considering death-censored graft survival, decade of transplantation, recipient age, donor age, living donor, transplant number, ischaemic time, time on renal replacement therapy prior to transplant and HLA mismatch at HLA-A, -B and -DR was conducted. In the multivariate analysis of recipient survival, diabetic nephropathy as primary renal disease was also included. Results: A total of 2395 kidney transplant recipients were analysed: 2062 (83.8%) with the 1st kidney transplant, 279 (11.3%) with the 2nd graft, 46 (2.2%) with the 3rd+. Mean age of 1st kidney transplant recipients was 43.6 ± 16.3 years, versus 39.9 ± 14.4 for 2nd and 41.4 ± 11.5 for 3rd+ (p < 0.001). Aside from being younger, repeated kidney transplant patients were also more often males (p = 0.006), with a longer time spent on renal replacement therapy (p < 0.0001) and a higher degree of sensitisation, expressed as calculated reaction frequency (p < 0.001). There was also an association between multiple kidney transplants and better HLA match at transplantation (p < 0.0001). A difference in death-censored graft survival by number of transplants was seen, with a median graft survival of 328 months for recipients of the 1st transplant, 209 months for the 2nd and 150 months for the 3rd+ (p = 0.038). The same difference was seen in deceased donor kidneys (p = 0.048), but not in grafts from living donors (p = 0.2). Patient survival was comparable between the three groups (p = 0.59). Conclusions: In the attempt to expand the organ donor pool, particular attention should be reserved to high complex recipients, such as the repeated kidney transplant population. In this peculiar context, the quality of the donor has been shown to represent a main determinant for graft survival—in fact, kidney retrieved from living donors provide comparable outcomes to those from single-graft recipients.

Immunosuppression with Calcineurin Inhibitor after Renal Transplant Failure Inhibits Allosensitization

Immunosuppression withdrawal after graft failure seems to favor sensitization. A high percentage of calculated panel-reactive antibody (cPRA) and the development of de novo donor specific antibodies (dnDSA) indicate human leukocyte antigen (HLA) sensitization and may hinder the option of retransplantation. There are no established protocols on the immunosuppressive treatment that should be maintained after transplant failure. A retrospective analysis including 77 patients who lost their first renal graft between 1 January 2006–31 December 2015 was performed. Two sera were selected per patient, one immediately prior to graft loss and another one after graft failure. cPRA was calculated by Single Antigen in all patients. It was possible to analyze the development of dnDSA in 73 patients. By multivariate logistic regression analysis, the absence of calcineurin inhibitor (CNI) at 6 months after graft failure was related to cPRA > 75% (OR 4.8, CI 95% 1.5–15.0, p = 0.006). The absence of calcineurin inhibitor (CNI) at 6 months after graft loss was significantly associated with dnDSA development (OR 23.2, CI 95% 5.3–100.6, p < 0.001). Our results suggest that the absence of CNI at the sixth month after graft loss is a risk factor for sensitization. Therefore, maintenance of an immunosuppressive regimen based on CNI after transplant failure should be considered when a new transplant is planned, since it seems to prevent HLA allosensitization.

Donor-specific antibodies detected by single antigen beads alone can help risk stratify patients undergoing retransplantation across a repeat HLA mismatch

Whether reexposure to mismatched HLA antigens (RMM) in the setting of a negative crossmatch is associated with increased immunological risk remains an area of uncertainty. This is due to evidence derived predominantly from registry data, which lacks comprehensive information on alloantibody and rejection. In this study, we analyze the impact of low-level preformed donor-specific antibodies (DSA) against an RMM on transplant outcomes. From 1988 consecutive renal transplant recipients, we analyzed 179 patients undergoing retransplantation, of whom 55 had a RMM. All patients were crossmatch negative and preformed DSA were detected by single antigen beads alone. Multivariate analysis revealed that patients with preformed DSA against an RMM were independently at risk of antibody-mediated rejection (HR 8.70 [3.42-22.10], P < .0001) and death-censored allograft loss (HR 3.08 [1.17-8.14], P = .023). In addition, prior transplant nephrectomy (HR 2.04 [1.00-4.17], P = .0495) was also associated with allograft failure, whereas receiving a retransplant that was matched at HLA class II was associated with a favorable outcome (HR 0.37 [0.14-0.99], P = .047). In the absence of preformed DSA, an RMM was not associated with de novo DSA development, rejection, or allograft loss. In conclusion, an RMM portends increased immunological risk only in the presence of a preformed DSA in patients undergoing retransplantation.