The Impact of Withdrawal of Maintenance Immunosuppression and Graft Nephrectomy on HLA Sensitization and Calculated Chance of Future Transplant

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.

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.

Challenges in the management of the kidney allograft: from decline to failure: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

In March 2022, Kidney Disease: Improving Global Outcomes (KDIGO) held a virtual Controversies Conference to address the important but rarely examined phase during which the kidney transplant is failing or has failed. In addition to discussing the definition of a failing allograft, 4 broad areas were considered in the context of a declining functioning graft: prognosis and kidney failure trajectory; immunosuppression strategies; management of medical and psychological complications, and patient factors; and choice of kidney replacement therapy or supportive care following graft loss. Identifying and paying special attention to individuals with failing allografts was felt to be important in order to prepare patients psychologically, manage immunosuppression, address complications, prepare for dialysis and/or retransplantation, and transition to supportive care. Accurate prognostication tools, although not yet widely available, were embraced as necessary to define allograft survival trajectories and the likelihood of allograft failure. The decision of whether to withdraw or continue immunosuppression after allograft failure was deemed to be based most appropriately on risk-benefit analysis and likelihood of retransplantation within a few months. Psychological preparation and support was identified as a critical factor in patient adjustment to graft failure, as was early communication. Several models of care were noted that enabled a medically supportive transition back to dialysis or retransplantation. Emphasis was placed on the importance of dialysis-access readiness before initiation of dialysis, in order to avoid use of central venous catheters. The centrality of the patient to all management decisions and discussions was deemed to be paramount. Patient "activation," which can be defined as engaged agency, was seen as the most effective way to achieve success. Unresolved controversies, gaps in knowledge, and areas for research were also stressed in the conference deliberations.

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.

Allograft nephrectomy vs. no nephrectomy for failed renal transplants

The role of allograft nephrectomy (AN) in failed renal transplants is a topic of debate, owing to controversial results reported in the literature and the fact that most of the studies are limited by a retrospective design and small numbers of participants. Allograft nephrectomy is most likely of benefit in the patient with recurrent allograft intolerance syndrome (AIS) following pulse steroids. Immunosuppression weaning in the presence of clinical signs related to a chronic inflammatory state is also reasonable grounds to pursue AN. Studies are mainly inconclusive but suggest that AN has no overall benefit for allograft survival after retransplant. This topic is still of interest in the transplant field and is particularly relevant for patients who are likely to require retransplantation within their lifetime. Further assessment is needed in the form of randomized controlled trials that control for various AN indications and immunosuppression regimens, and have clearly defined survival 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.

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.

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.

Managing Patients with Failing Kidney Allograft: Many Questions Remain

Patients who receive a kidney transplant commonly experience failure of their allograft. Transplant failure often comes with complex management decisions, such as when and how to wean immunosuppression and start the transition to a second transplant or to dialysis. These decisions are made in the context of important concerns about competing risks, including sensitization and infection. Unfortunately, the management of the failed allograft is, at present, guided by relatively poor-quality data and, as a result, practice patterns are variable and suboptimal given that patients with failed allografts experience excess morbidity and mortality compared with their transplant-naive counterparts. In this review, we summarize the management strategies through the often-precarious transition from transplant to dialysis, highlighting the paucity of data and the critical gaps in our knowledge that are necessary to inform the optimal care of the patient with a failing kidney transplant.

Highly sensitised patients awaiting deceased donor renal transplants are disadvantaged by the presence of denatured HLA antibody detected in routine HLA antibody testing

Luminex Single Antigen Bead (SAB) assays used to detect HLA antibodies may artificially increase sensitisation in highly sensitised patients. The presence of denatured HLA (dHLA) within the assay enables antibodies specific to cryptic HLA epitopes to bind, such antibodies are not clinically relevant. We sought to exclude dHLA reactivity in a cohort of very highly sensitised patients (HSP), calculated reaction frequency (cRF) 95-100%, and determine the effect upon sensitisation. Such patients have limited access to suitable donors and small changes in their HLA antibody profile, particularly where their cRF is 100%, can increase their opportunity of a transplant. We determined the presence of dHLA by aligning antibody reactivity which did not correspond to known HLA class I epitope mismatches with the results of assays modified to detect class I dHLA. 130 class I dHLA reactions were identified within 11 HSP, all of whom had clear sensitising events. cRF was corrected for dHLA, mean cRF 98.2% (93-100) pre and 95.5% (87-100) post correction (P = 0.0156). An increase in the number of predicted compatible donors (p = 0.0078) after dHLA correction was demonstrated. Two manufacturers SAB assays were used. A reduction of patients with 100% cRF was observed for both manufactures. dHLA is contributing to sensitisation in HSP and is detrimental to their chances of receiving a compatible transplant. The observed dHLA reactivity varied according to kit manufacturers (P = 0.0001), this is potentially a useful finding for laboratories wishing to discriminate between nHLA and dHLA, but without the resources required to regularly perform dHLA assay and epitope analyses. This article is protected by copyright. All rights reserved.

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.

The failing kidney allograft: A review and recommendations for the care and management of a complex group of patients

The return to dialysis after allograft failure is associated with increased morbidity and mortality. This transition is made more complex by the rising numbers of patients who seek repeat transplantation and therefore may have indications for remaining on low levels of immunosuppression, despite the potential increased morbidity. Management strategies vary across providers, driven by limited data on how to transition off immunosuppression as the allograft fails and a paucity of randomized controlled trials to support one approach over another. In this review, we summarize the current data available for management and care of the failing allograft. Additionally, we discuss a suggested plan for immunosuppression weaning based upon the availability of re-transplantation and residual allograft function. We propose a shared-care model in which there is improved coordination between transplant providers and general nephrologists so that immunosuppression management and preparation for renal replacement therapy and/or repeat transplantation can be conducted with the goal of improved outcomes and decreased morbidity in this vulnerable patient group.

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.

Long-term outcomes after kidney transplant failure and variables related to risk of death and probability of retransplant: Results from a single-center cohort study in Brazil

Background

Returning to dialysis after kidney graft loss (GL) is associated with a high risk of mortality, mainly in the first 3–6 months. The follow-up of patients with GL should be extended to better understand crude patient outcomes, mainly in emerging countries, where the transplantation activity has increased.

Methods

This is a historical single-center cohort study conducted in an emerging country (Brazil) that included 115 transplant patients with kidney allograft failure who were followed for 44.1 (21.4; 72.6) months after GL. The outcomes were death or retransplantation after GL calculated by Kaplan-Meier and log-rank tests. Proportional hazard ratios for death and retransplantation were assessed by Cox regression.

Results

The 5-year probability of retransplantation was 38.7% (95% CI: 26.1%-51.2%) and that of death was 37.7% (95% CI: 24.9%-50.5%); OR = 1.03 (95% CI: 0.71–1.70) and P = 0.66. The likelihood of retransplantation was higher in patients who resumed dialysis with higher levels of hemoglobin (HR = 1.22; 95% CI = 1.04–1.43; P = 0.01) and lower in blood type O patients (HR = 0.48; 95% CI = 0.25–0.93; P = 0.03), which was associated with a lower frequency of retransplantation with a subsequent living-donor kidney. On the other hand, the risk of death was significantly associated with Charlson comorbidity index (HR for each point = 1.37; 95% CI 1.19–1.50; P<0.001), and residual eGFR at the time when patients had resumed to dialysis (HR for each mL = 1.14; 95% CI = 1.05–1.25; P = 0.002). The trend toward a lower risk of death when patients had resumed to dialysis using AV fistula access was observed (HR = 0.50; 95% CI 0.25–1.02; P = 0.06), while a higher risk seems to be associated with the number of previous engraftment (HR = 2.01; 95% CI 0.99–4.07; P = 0.05).

Conclusions

The 5-year probability of retransplantation was not less than that of death. Variables related to the probability of retransplantation were hemoglobin level before resuming dialysis and ABO blood type, while the risk of death was associated with comorbidities and residual eGFR.

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.

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.

The omission of the "wet" pre-transplant crossmatch in renal transplant centres in Scotland

The methods used for assessment of immunological risk for a patient receiving a kidney from a deceased donor have undergone significant change in the last few years. Many centres now proceed to transplant without any additional laboratory-based HLA testing for patients who are well defined as HLA antibody negative. Using rapid HLA antibody tests at the time of donor offer, such as Luminex, it is also possible to omit wet crossmatches in many sensitised patients. This virtual crossmatch (vXM) approach provides benefits in reducing cold ischaemia time (CIT), but also carries risks such as missing clinically relevant non-HLA reactivity or allelic HLA antibody reactivity. A number of factors need to be in place in a laboratory to enable a vXM policy to be extended to both sensitised and non-sensitised patients including access to complete donor HLA typing, ability to undertake Luminex-based HLA antibody testing out of working hours, and access to senior H&I Scientist expertise to assess and interpret results. Other approaches, such as using peripheral blood lymphocytes for crossmatching, may also enable a reduction in CIT and transplant units need to assess the risks of extending vXM processes for their patients against potential benefits.