Rescue Allocation Modes in Eurotransplant Kidney Transplantation: Recipient Oriented Extended Allocation Versus Competitive Rescue Allocation-A Retrospective Multicenter Outcome Analysis

BACKGROUND

Whenever the kidney standard allocation (SA) algorithms according to the Eurotransplant (ET) Kidney Allocation System or the Eurotransplant Senior Program fail, rescue allocation (RA) is initiated. There are 2 procedurally different modes of RA: recipient oriented extended allocation (REAL) and competitive rescue allocation (CRA). The objective of this study was to evaluate the association of patient survival and graft failure with RA mode and whether or not it varied across the different ET countries.

METHODS

The ET database was retrospectively analyzed for donor and recipient clinical and demographic characteristics in association with graft outcomes of deceased donor renal transplantation (DDRT) across all ET countries and centers from 2014 to 2021 using Cox proportional hazards methods.

RESULTS

Seventeen thousand six hundred seventy-nine renal transplantations were included (SA 15 658 [89%], REAL 860 [4.9%], and CRA 1161 [6.6%]). In CRA, donors were older, cold ischemia times were longer, and HLA matches were worse in comparison with REAL and especially SA. Multivariable analyses showed comparable graft and recipient survival between SA and REAL; however, CRA was associated with shorter graft survival. Germany performed 76% of all DDRTs after REAL and CRA and the latter mode reduced waiting times by up to 2.9 y.

CONCLUSIONS

REAL and CRA are used differently in the ET countries according to national donor rates. Both RA schemes optimize graft utilization, lead to acceptable outcomes, and help to stabilize national DDRT programs, especially in Germany.

Immunosuppression of HLA identical living-donor kidney transplant recipients: A systematic review

BACKGROUND

Kidney transplant (KT) recipients of HLA identical siblings (HLAid) have lower immunological risk, but there are no specific recommendations for immunosuppression. Our aim was to analyze evidence about results from HLAid living-donor recipients under different immunosuppression in the current era of immunological risk assessment.

METHODS

Systematic review of studies describing associations between outcomes of HLAid living-donor KT recipients according to their immunological risk and applied immunosuppression.

RESULTS

From 1351 studies, 16 (5636 KT recipients) were included in the analysis. All studies were retrospective, ten comparing immunosuppression strategies, and six immunological risk strata. Of those ten, six studies were published in 1990 or earlier and only three included tacrolimus. The evidence is poor, and the inclusion of calcineurin inhibitors does not demonstrate better results. Furthermore, only few studies describe different immunosuppression regimens according to the patient immunological risk and, in general, they do not include the assessment with new solid phase assays.

CONCLUSIONS

There are no studies analyzing the association of outcomes of HLAid KT recipients with current immunological risk tools. In the absence of evidence, no decision or proposal of immunosuppression adapted to modern immunological risk assessment can be made currently by the Descartes Working Group.

Kidney transplantation during mass disasters - from COVID-19 to other catastrophes A Consensus Statement by the DESCARTES Working Group and Ethics Committee of the ERA

Mass disasters are characterized by a disparity between health care demand and supply, which hampers complex therapies like kidney transplantation. Considering scarcity of publications on previous disasters, we reviewed transplantation practice during the recent COVID-19 pandemic, and dwelled upon this experience for guiding transplantation strategies in the future pandemic and non-pandemic catastrophes. We strongly suggest continuing transplantation programs during mass disasters, if medical and logistic operational circumstances are appropriate. Postponing transplantations from living donors and referral of urgent cases to safe regions or hospitals are justified. Specific preventative measures in anticipated disasters (such as vaccination programs during pandemics or evacuation in case of hurricanes or wars) may be useful to minimize risks. Immunosuppressive therapies should consider stratifying risk status and avoiding heavy immune suppression in patients with a low probability of therapeutic success. Discharging patients at the earliest convenience is justified during pandemics, whereas delaying discharge is reasonable in other disasters, if infrastructural damage results in unhygienic living environments for the patients. In the outpatient setting, telemedicine is a useful approach to reduce the patient load to hospitals, to minimize the risk of nosocomial transmission in pandemics and the need for transport in destructive disasters. If it comes down to save as many lives as possible, some ethical principles may vary in function of disaster circumstances, but elementary ethical rules are non-negotiable. Patient education is essential to minimize disaster-related complications and to allow for an efficient use of health care resources.

The 3-Step Model of informed consent for living kidney donation: a proposal on behalf of the DESCaRTES Working Group of the European Renal Association

Living donation challenges the ethical principle of non-maleficence in that it exposes healthy persons to risks for the benefit of someone else. This makes safety, informed consent (IC) and education a priority. Living kidney donation has multiple benefits for the potential donor, but there are also several known short- and long-term risks. Although complete standardization of IC is likely to be unattainable, studies have emphasized the need for a standardized IC process to enable equitable educational and decision-making prospects for the prevention of inequities across transplant centers. Based on the Three-Talk Model of shared decision making by Elwyn et al., we propose a model, named 3-Step (S) Model, where each step coincides with the three ideal timings of the process leading the living donor to the decision to pursue living donation: prior to the need for kidney replacement therapy (team talk); at the local nephrology unit or transplant center, with transplant clinicians and surgeons prior to evaluations start (option talk); and throughout evaluation, after having learned about the different aspects of donation, especially if there are second thoughts or doubts (decision talk). Based on the 3-S Model, to deliver conceptual and practical guidance to nephrologists and transplant clinicians, we provide recommendations for standardization of the timing, content, modalities for communicating risks, and assessment of understanding prior to donation. The 3-S Model successfully allows an integration between standardization and individualization of IC, enabling a person-centered approach to potential donors. Studies will assess the effectiveness of the 3-S Model in kidney transplant clinical practice.

Factors influencing kidney transplantation rates: a study from the ERA Registry

BACKGROUND

Large international differences exist in kidney transplantation (KT) rates. We aimed to investigate which factors may explain the total, deceased donor, and living donor KT rates over the last decade.

METHODS

KT experts from 39 European countries completed the Kidney Transplantation Rate Survey on measures and barriers and their potential effect on the KT rate in their country. In the analyses, countries were divided into low, middle, and high KT rate countries based on the KT rate at the start of study period in 2010.

RESULTS

Experts from low KT rate countries reported more frequently to have taken measures regarding staff, equipment and facilities to increase total KT rate compared with middle and high KT rate countries. For donor type specific KT, the largest international differences in measures taken were reported for deceased donor KT, with middle and high KT rate countries taking more measures, such as the use of expanded criteria donor kidneys, the presence of transplantation coordinators, and (inter)national exchange of donor kidneys. Once a measure was taken, experts' opinion on its success was similar across the low, middle and high KT rate countries. Experts from low KT rate countries more often reported potential barriers, such as patients' lack of knowledge and distrust in the health care system.

CONCLUSIONS

In particular in low KT rate countries, KT rate might be stimulated by optimizing staff, equipment, and facilities. In addition, all countries may benefit from deceased and living donor specific measures.

Can We Predict Graft Intolerance Syndrome After Kidney Transplant Failure? External Validation of a Previously Developed Model

Previously we established a prediction model for graft intolerance syndrome requiring graft nephrectomy in patients with late kidney graft failure. The aim of this study is to determine generalizability of this model in an independent cohort. The validation cohort included patients with late kidney graft failure between 2008 and 2018. Primary outcome is the prognostic performance of our model, expressed as the area under the receiver operating characteristic curve (ROC-AUC), in the validation cohort. In 63 of 580 patients (10.9%) a graft nephrectomy was performed because of graft intolerance. The original model, which included donor age, graft survival and number of acute rejections, performed poorly in the validation cohort (ROC-AUC 0.61). After retraining of the model using recipient age at graft failure instead of donor age, the model had an average ROC-AUC of 0.70 in the original cohort and of 0.69 in the validation cohort. Our original model did not accurately predict the graft intolerance syndrome in a validation cohort. However, a retrained model including recipient age at graft failure instead of donor age performed moderately well in both the development and validation cohort enabling identification of patients with the highest and lowest risk of graft intolerance syndrome.

Issues regarding COVID-19 in kidney transplantation in the era of the omicron variant: a commentary by the era descartes working group

The Omicron variant, which has become the dominant strain of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) worldwide, brings new challenges to preventing and controlling the infection. Moreover, the widespread implementation of vaccination policies before and after transplantation, and the development of new prophylactic and treatment strategies for coronavirus disease 2019 (COVID-19) over the past 12–18 months, has raised several new issues concerning kidney transplant recipients. In this special report, the ERA DESCARTES (Developing Education Science and Care for Renal Transplantation in European States) Working Group addresses several questions related to everyday clinical practice concerning kidney transplant recipients and to the assessment of deceased and live kidney donors: what is the current risk of severe disease and of breakthrough infection, the optimal management of immunosuppression in kidney transplant recipients with COVID-19, the role of passive immunization and the efficacy of antiviral drugs in ambulatory patients, the management of drug-to-drug interactions, safety criteria for the use of SARS-CoV-2-positive donors, issues related to the use of T cell depleting agents as induction treatment, and current recommendations for shielding practices.

Proposed Definitions of Antibody-Mediated Rejection for Use as a Clinical Trial Endpoint in Kidney Transplantation

Antibody-mediated rejection (AMR) is caused by antibodies that recognize donor human leukocyte antigen (HLA) or other targets. As knowledge of AMR pathophysiology has increased, a combination of factors is necessary to confirm the diagnosis and phenotype. However, frequent modifications to the AMR definition have made it difficult to compare data and evaluate associations between AMR and graft outcome. The present paper was developed following a Broad Scientific Advice request from the European Society for Organ Transplantation (ESOT) to the European Medicines Agency (EMA), which explored whether updating guidelines on clinical trial endpoints would encourage innovations in kidney transplantation research. ESOT considers that an AMR diagnosis must be based on a combination of histopathological factors and presence of donor-specific HLA antibodies in the recipient. Evidence for associations between individual features of AMR and impaired graft outcome is noted for microvascular inflammation scores ≥2 and glomerular basement membrane splitting of >10% of the entire tuft in the most severely affected glomerulus. Together, these should form the basis for AMR-related endpoints in clinical trials of kidney transplantation, although modifications and restrictions to the Banff diagnostic definition of AMR are proposed for this purpose. The EMA provided recommendations based on this Broad Scientific Advice request in December 2020; further discussion, and consensus on the restricted definition of the AMR endpoint, is required.

Kidney Transplantation After Rescue Allocation-the Eurotransplant Experience: A Retrospective Multicenter Outcome Analysis

BACKGROUND

At Eurotransplant (ET), kidneys are transferred to "rescue allocation" (RA), whenever the standard allocation (SA) algorithms Eurotransplant Kidney Allocation System (ETKAS) and Eurotransplant Senior Program (ESP) fail. We analyzed the outcome of RA.

METHODS

Retrospective patient clinical and demographic characteristics association analyses were performed with graft outcomes for 2422 recipients of a deceased donor renal transplantation (DDRT) after RA versus 25 481 after SA from 71 centers across all ET countries from 2006 to 2018.

RESULTS

Numbers of DDRTs after RA increased over the time, especially in Germany. RA played a minor role in ESP versus ETKAS (2.7% versus 10.4%). RA recipients and donors were older compared with SA recipients and donors, cold ischemia times were longer, waiting times were shorter, and the incidence of primary nonfunction was comparable. Among ETKAS recipients, HLA matching was more favorable in SA (mean 3.7 versus 2.5). In multivariate modeling, the incidence of graft loss in ETKAS recipients was reduced in RA compared with SA (subdistribution hazard ratio, 0.80; 95% confidence interval [0.70-0.91], P < 0.001), whereas other outcomes (mortality, death with functioning graft (DwFG)) were not significantly different. None of the 3 outcomes were significantly different when comparing RA with SA within the ESP program.

CONCLUSIONS

Facing increased waiting times and mortality on dialysis due to donor shortage, this study reveals encouragingly positive DDRT outcomes following RA. This supports the extension of RA to more patients and as an alternative tool to enable transplantation in patients in countries with prohibitively long waiting times or at risk of deterioration.

Allograft Function as Endpoint for Clinical Trials in Kidney Transplantation

Clinical study endpoints that assess the efficacy of interventions in patients with chronic renal insufficiency can be adopted for use in kidney transplantation trials, given the pathophysiological similarities between both conditions. Kidney dysfunction is reflected in the glomerular filtration rate (GFR), and although a predefined (e.g., 50%) reduction in GFR was recommended as an endpoint by the European Medicines Agency (EMA) in 2016, many other endpoints are also included in clinical trials. End-stage renal disease is strongly associated with a change in estimated (e)GFR, and eGFR trajectories or slopes are increasingly used as endpoints in clinical intervention trials in chronic kidney disease (CKD). Similar approaches could be considered for clinical trials in kidney transplantation, although several factors should be taken into account. The present Consensus Report was developed from documentation produced by the European Society for Organ Transplantation (ESOT) as part of a Broad Scientific Advice request that ESOT submitted to the EMA in 2020. This paper provides a contemporary discussion of primary endpoints used in clinical trials involving CKD, including proteinuria and albuminuria, and evaluates the validity of these concepts as endpoints for clinical trials in kidney transplantation.

Rationale for Surrogate Endpoints and Conditional Marketing Authorization of New Therapies for Kidney Transplantation

Conditional marketing authorization (CMA) facilitates timely access to new drugs for illnesses with unmet clinical needs, such as late graft failure after kidney transplantation. Late graft failure remains a serious, burdensome, and life-threatening condition for recipients. This article has been developed from content prepared by members of a working group within the European Society for Organ Transplantation (ESOT) for a Broad Scientific Advice request, submitted by ESOT to the European Medicines Agency (EMA), and reviewed by the EMA in 2020. The article presents the rationale for using surrogate endpoints in clinical trials aiming at improving late graft failure rates, to enable novel kidney transplantation therapies to be considered for CMA and improve access to medicines. The paper also provides background data to illustrate the relationship between primary and surrogate endpoints. Developing surrogate endpoints and a CMA strategy could be particularly beneficial for studies where the use of primary endpoints would yield insufficient statistical power or insufficient indication of long-term benefit following transplantation.

Surrogate Endpoints for Late Kidney Transplantation Failure

In kidney transplant recipients, late graft failure is often multifactorial. In addition, primary endpoints in kidney transplantation studies seek to demonstrate the short-term efficacy and safety of clinical interventions. Although such endpoints might demonstrate short-term improvement in specific aspects of graft function or incidence of rejection, such findings do not automatically translate into meaningful long-term graft survival benefits. Combining many factors into a well-validated model is therefore more likely to predict long-term outcome and better reflect the complexity of late graft failure than using single endpoints. If conditional marketing authorization could be considered for therapies that aim to improve long-term outcomes following kidney transplantation, then the surrogate endpoint for graft failure in clinical trial settings needs clearer definition. This Consensus Report considers the potential benefits and drawbacks of several candidate surrogate endpoints (including estimated glomerular filtration rate, proteinuria, histological lesions, and donor-specific anti-human leukocyte antigen antibodies) and composite scoring systems. The content was created from information prepared by a working group within the European Society for Organ Transplantation (ESOT). The group submitted a Broad Scientific Advice request to the European Medicines Agency (EMA), June 2020: the request focused on clinical trial design and endpoints in kidney transplantation. Following discussion and refinement, the EMA made final recommendations to ESOT in December 2020 regarding the potential to use surrogate endpoints in clinical studies that aim to improving late graft failure.

Proposed Definitions of T Cell-Mediated Rejection and Tubulointerstitial Inflammation as Clinical Trial Endpoints in Kidney Transplantation

The diagnosis of acute T cell-mediated rejection (aTCMR) after kidney transplantation has considerable relevance for research purposes. Its definition is primarily based on tubulointerstitial inflammation and has changed little over time; aTCMR is therefore a suitable parameter for longitudinal data comparisons. In addition, because aTCMR is managed with antirejection therapies that carry additional risks, anxieties, and costs, it is a clinically meaningful endpoint for studies. This paper reviews the history and classifications of TCMR and characterizes its potential role in clinical trials: a role that largely depends on the nature of the biopsy taken (indication vs protocol), the level of inflammation observed (e.g., borderline changes vs full TCMR), concomitant chronic lesions (chronic active TCMR), and the therapeutic intervention planned. There is ongoing variability—and ambiguity—in clinical monitoring and management of TCMR. More research, to investigate the clinical relevance of borderline changes (especially in protocol biopsies) and effective therapeutic strategies that improve graft survival rates with minimal patient morbidity, is urgently required. The present paper was developed from documentation produced by the European Society for Organ Transplantation (ESOT) as part of a Broad Scientific Advice request that ESOT submitted to the European Medicines Agency for discussion in 2020. This paper proposes to move toward refined definitions of aTCMR and borderline changes to be included as primary endpoints in clinical trials of kidney transplantation.

Microparticles in Autoimmunity: Cause or Consequence of Disease?

Microparticles (MPs) are small (100 nm - 1 um) extracellular vesicles derived from the plasma membrane of dying or activated cells. MPs are important mediators of intercellular communication, transporting proteins, nucleic acids and lipids from the parent cell to other cells. MPs resemble the state of their parent cells and are easily accessible when released into the blood or urine. MPs also play a role in the pathogenesis of different diseases and are considered as potential biomarkers. MP isolation and characterization is technically challenging and results in different studies are contradictory. Therefore, uniform guidelines to isolate and characterize MPs should be developed. Our understanding of MP biology and how MPs play a role in different pathological mechanisms has greatly advanced in recent years. MPs, especially if derived from apoptotic cells, possess strong immunogenic properties due to the presence of modified proteins and nucleic acids. MPs are often found in patients with autoimmune diseases where MPs for example play a role in the break of immunological tolerance and/or induction of inflammatory conditions. In this review, we describe the main techniques to isolate and characterize MPs, define the characteristics of MPs generated during cell death, illustrate different mechanism of intercellular communication via MPs and summarize the role of MPs in pathological mechanisms with a particular focus on autoimmune diseases.

MO337: Higher Antibody Response After 2 Vaccinations With MRNA-1273 as Compared With BNT162B2 and AZD1222 in High-Risk Kidney Patients

BACKGROUND AND AIMS

Lower antibody responses after SARS-Cov-2 vaccination have been reported in patients with severely impaired kidney function or patients with kidney replacement treatment. We compared humoral responses and reported adverse events of three vaccines (mRNA-1273, BNT162b2 and AZD1222) in kidney transplant recipients (KTRs), dialysis patients, patients with CKD stages G4–G5 and control subjects without kidney disease.

METHOD

KTRs, dialysis patients and patients with CKD stages G4–G5 were vaccinated with either mRNA-1273, BNT162b2 or AZD1222 during the Dutch SARS-CoV-2 vaccination program. Control subjects were all vaccinated with mRNA-1273. Blood samples were obtained at 1 month after two vaccinations by home-based finger prick tests and were analysed for the presence of IgG antibodies against the receptor-binding domain of the spike protein of SARS-CoV-2 using the Sanquin anti-SARS-CoV-2 RBD IgG ELISA assay. Primary endpoints were the antibody titer and reported systemic adverse events (AEs) at 1 month after the second vaccination. Multivariate regression analysis was performed on the difference between vaccines with respect to antibody titer and AEs after correction for sex, ethnicity, BMI, eGFR, dialysis vintage, transplantation characteristics and use of immunosuppressive drugs.

RESULTS

A total of 2468 KTRs, 480 dialysis patients, 400 patients with CKD stages G4–G5 and 186 control subjects were enrolled. KTRs had lower antibody titers (66 [8–573] BAU/mL) in comparison to dialysis patients [1375 (431–2896) BAU/mL], patients with CKD stages G4–G5 [2097 (828–4077) BAU/mL] and control subjects [3713 (2291–6451) BAU/mL]. mRNA-1273 demonstrated a higher antibody titer compared with BNT162b2 in KTR [72 (9–638) versus 21 (6–128) BAU/mL; P &lt; .001), dialysis patients [1675 (573–3031) versus 636 (216–1416) BAU/mL; P &lt; .001] and patients with CKD stages G4–G5 [2879 (1425–5311) versus 1063 (389–1939) BAU/mL; P &lt; .001). In a similar pattern, mRNA-1273 demonstrated a higher antibody titer compared with AZD1222 (P &lt; .001 in all groups). Multivariate analysis revealed that BNT162b2 and AZD1222 were significantly associated with lower antibody levels compared with mRNA-1273 in all 3 patient groups. BNT162b2 demonstrated less frequently systemic AEs compared with mRNA-1273 in KTRs (12% versus 27%; P &lt; .001), dialysis patients (12% versus 29%; P = .007) and in patients with CKD G4–G5 (18% versus 67%, P &lt; .001). AZD1222 demonstrated less systemic AEs compared with mRNA-1273 only in patients with CKD stages G4–G5 (39% versus 67%; P = .03). Multivariate analysis revealed that BNT162b2 was associated with fewer systemic AEs in only dialysis patients (P = .04) and patients with CKD stages G4–G5 (P = .02).

CONCLUSION

mRNA-1273 demonstrated significantly higher antibody levels at 1 month after 2 vaccinations as compared with BNT162b2 and AZD1222 in high-risk patients with kidney disease. BNT162b2 was associated with a fewer systemic AEs in dialysis patients and patients with CKD stages G4–G5, although these AEs were mild and self-limiting. mRNA-1273 may therefore be considered as the preferred SARS-CoV-2 vaccine in high-risk patients with kidney disease. Whether the higher antibody response following vaccination with mRNA-1273 sustains and results in a better protection against COVID-19 is yet to be analysed.

MO184: Development and Validation of a Multivariable Prediction Model for Nonseroconversion after SARS-COV-2 Vaccination in Kidney Transplant Recipients

BACKGROUND AND AIMS

Kidney transplant recipients (KTRs) are still at risk of fatal COVID-19 disease after SARS-CoV-2 vaccination, even after a third booster vaccination. With the spread of new SARS-CoV-2 variants, great urgency exists for a better understanding of the factors that impact the immune response in these patients. Our aim was to predict nonseroconversion after SARS-CoV-2 vaccination to understand the factors that may disrupt the humoral response in KTRs.

METHOD

A multivariable logistic regression model was developed and validated that uses routinely available clinical and laboratory information to predict nonseroconversion after two doses of SARS-CoV-2 mRNA vaccination in KTRs. KTRs were prospectively enrolled to the Dutch REnal patients COVID-19 VACcination (RECOVAC) consortium, specifically to the Immune Response (IR) study with four participating university medical centres in the Netherlands. The discovery cohort consisted of three participating centres (Amsterdam UMC, Radboud UMC Nijmegen and Erasmus MC Rotterdam), and the validation cohort of patients treated in UMC Groningen. A large second validation set from the RECOVAC consortium (LESS-CoV-2) was used to test a more simplified version of the model without lymphocyte counts. All participants received two doses of the mRNA-1273 COVID-19 vaccine (Moderna) and had no history of SARS-CoV-2 infection. Participants were classified as responder or non-responder based on seroconversion at day 28 following the second vaccination with a threshold for seropositivity based on receiver operator curve analysis set at S1-specific IgG antibody concentration ≥10 BAU/mL.

RESULTS

The discovery cohort included 215 KTRs of which 126 responders and 89 non-responders. After backward selection, 6 out of 19 factors remained predictive for nonseroconversion: increased age, lower lymphocyte count, lower estimated glomerular filtration rate (eGFR), shorter time after transplantation, not using steroids and the use of mycophenolate mofetil/mycophenolic acid (MMF/MPA) (Figure 1). The area under the curve (AUC) of the receiver operating characteristics was 0.83 (95% confidence interval 0.78–0.89) in the discovery cohort after adjustment for optimism and 0.84 (0.74–0.94) in external validation of the UMC Groningen cohort (n = 73), and 0.75 (0.72–0.77) in external validation of the LESS-CoV-2 dataset (n = 2484). In addition, MMF/MPA appeared to have a dose-dependent unfavourable association with the S1 IgG antibody titer (Figure 2).

CONCLUSION

Six predictors allow for a better understanding of the process of the development of the humoral response in KTRs. These predictors could be applied to individualized patient counseling and treatment strategy during the COVID-19 pandemic and future innovative vaccine trial design for this complex patient group.

MO899: The Clinical frailty Scale is Useful for ICU Triage in Dialysis Patients With COVID-19–An Eracoda Analysis

BACKGROUND AND AIMS

during the COVID-19 pandemic, several guidelines have recommended the use of the Clinical Frailty Scale (CFS) for triage of critically ill patients with COVID-19 in case of shortage in ICU resources. However, no data on using CFS assessment for ICU triage for dialysis patients is yet available. This study evaluates whether CFS is associated with mortality rates in a cohort of hospitalized dialysis patients with COVID-19.

METHOD

the analyses are based on data of the European Renal Association COVID-19 Database (ERACODA). Dialysis patients who presented with COVID-19 between 1 February 2020 and 30 April 2021 and with complete information on CFS and vital status at 3 months were included. Study outcomes were hospital and ICU admission rates and hospital and ICU mortality at 3 months after hospital admission. Cox regression analyses were performed to assess the association of CFS category (≤5 versus ≥ 6) and study outcomes in line with Dutch ICU triage guidelines for COVID-19. Furthermore, additional subgroup analyses were performed to assess the association between CFS and 3-month mortality by age category (<65, 65–75 and >75 years).

RESULTS

among a total of 2206 dialysis patients (mean age = 67.2 (14.1) years, male sex = 61%), 1694 (77%) had CFS ≤ 5 and 514 (23%) had CFS ≥ 6. Hospitalization rate was comparable in patients with CFS ≤ 5 and in patients with CFS ≥ 6 (67 and 71%, respectively), whereas the rate of ICU admission was higher in patients with CFS ≤ 5 than in patients with CFS ≥ 6 (16 versus 9%, p = 0.001). Among 1501 hospitalized patients, 3-month mortality was 26% of patients with CFS ≤ 5 and 59% in patients with CFS ≥ 6 (P < 0.001). Multivariate analysis with adjustment for patient demographics, smoking status and BMI revealed that CFS ≥ 6 was associated with hospital mortality [aHR 2.27 (1.88–2.74) versus CFS ≤ 5; P < 0.001) with a significant interaction for age (P = 0.029). aHR was 4.00 (2.56–6.37; CFS ≥ 6 versus CFS ≤ 5; P < 0.001) in patients < 65 years, aHR was 1.87 (1.33–2.64; CFS ≥ 6 versus CFS ≤ 5; P < 0.001) in patients 65–75 years and aHR was 2.12 (1.64–2.75; CFS ≥ 6 versus CFS ≤ 5; P < 0.001) in patients >75 years. Among 219 ICU admitted patients, 3-month mortality was 60% of the patients with CFS ≤ 5 and 91% in the patients with CFS ≥ 6, respectively. Multivariate analysis with adjustment for patient demographics, smoking status and BMI revealed that CFS ≥ 6 was associated with ICU mortality [aHR 1.80 (1.17–2.77); CFS ≥ 6 versus CFS ≤ 5; P = 0.002].

CONCLUSION

more frail dialysis patients with CFS ≥ 6 who are hospitalized for COVID-19 were less often admitted to the ICU, but in case they were admitted to the ICU they have a very high mortality of 91% in this cohort study. In fit to mildly frail dialysis, patients who were admitted to the ICU, mortality rates are lower. The association between frailty and hospital mortality is interacted by age with the strongest association in patients younger than 65 years. These findings suggest that CFS may be a useful complementary triage tool for ICU admission of dialysis patients during the ongoing COVID-19 pandemic.

Long-term efficacy and safety of SARS-CoV-2 vaccination in patients with chronic kidney disease, on dialysis or after kidney transplantation: a national prospective observational cohort study

Background

COVID-19 is associated with increased morbidity and mortality in patients with chronic kidney disease (CKD) stages G4-G5, on dialysis or after kidney transplantation (kidney replacement therapy, KRT). SARS-CoV-2 vaccine trials do not elucidate if SARS-CoV-2 vaccination is effective in these patients. Vaccination against other viruses is known to be less effective in kidney patients. Our objective is to assess the efficacy and safety of various types of SARS-CoV-2 vaccinations in patients with CKD stages G4-G5 or on KRT.

Methods

In this national prospective observational cohort study we will follow patients with CKD stages G4-G5 or on KRT (n = 12,000) after SARS-CoV-2 vaccination according to the Dutch vaccination program. Blood will be drawn for antibody response measurements at day 28 and month 6 after completion of vaccination. Patient characteristics and outcomes will be extracted from registration data and questionnaires during 2 years of follow-up. Results will be compared with a control group of non-vaccinated patients. The level of antibody response to vaccination will be assessed in subgroups to predict protection against COVID-19 breakthrough infection.

Results

The primary endpoint is efficacy of SARS-CoV-2 vaccination determined as the incidence of COVID-19 after vaccination. Secondary endpoints are the antibody based immune response at 28 days after vaccination, the durability of this response at 6 months after vaccination, mortality and (serious) adverse events.

Conclusion

This study will fulfil the lack of knowledge on efficacy and safety of SARS-CoV-2 vaccination in patients with CKD stages G4-G5 or on KRT.

Trial registration

The study protocol has been registered in clinicaltrials.gov(NCT04841785).

Current knowledge about this subject

COVID-19 has devastating impact on patients with CKD stages G4-G5, on dialysis or after kidney transplantation.

Effective SARS-CoV-2 vaccination is very important in these vulnerable patient groups.

Recent studies on vaccination in these patient groups are small short-term studies with surrogate endpoints.

Contribution of this study

Assessment of incidence and course of COVID-19 after various types of SARS-CoV-2 vaccination during a two-year follow-up period in not only patients on dialysis or kidney transplant recipients, but also in patients with CKD stages G4-G5.

Quantitative analysis of antibody response after SARS-CoV-2 vaccination and its relationship with incidence and course of COVID-19 in patients with CKD stages G4-G5, on dialysis or after kidney transplantation compared with a control group.

Monitoring of (serious) adverse events and development of anti-HLA antibodies.

Impact on practice or policy

Publication of the study design contributes to harmonization of SARS-CoV-2 vaccine study

methodology in kidney patients at high-risk for severe COVID-19.

Data on efficacy of SARS-CoV-2 vaccination in patients with CKD will provide guidance for future vaccination policy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-022-02680-3.

Assessment of Pre-Donation Glomerular Filtration Rate: Going Back To Basics A Position Paper from the DESCARTES Working Group of the ERA-EDTA

The 2017 version of the KDIGO (Kidney Disease: Improving Global Outcomes) guidelines is the most recent international framework for the evaluation and care of living kidneys donors. Along with the call for an integrative approach evaluating the long-term end-stage kidney disease risk for the future potential donor, several recommendations are formulated regarding the predonation glomerular filtration rate (GFR) adequacy with no or little consideration for the donor candidate's age and for the importance of using reference methods of GFR measurements. Herein, we question the position of the KDIGO guidelines and discuss the rationale and modalities for a more basic, but not less demanding GFR evaluation susceptible to enable a more efficient selection of the potential kidney donor.

Rationale and design of the OPTIMIZE trial: OPen label multicenter randomized trial comparing standard IMmunosuppression with tacrolimus and mycophenolate mofetil with a low exposure tacrolimus regimen In combination with everolimus in de novo renal transplantation in Elderly patients

BACKGROUND

In 2019, more than 30 % of all newly transplanted kidney transplant recipients in The Netherlands were above 65 years of age. Elderly patients are less prone to rejection, and death censored graft loss is less frequent compared to younger recipients. Elderly recipients do have increased rates of malignancy and infection-related mortality. Poor kidney transplant function in elderly recipients may be related to both pre-existing (i.e. donor-derived) kidney damage and increased susceptibility to nephrotoxicity of calcineurin inhibitors (CNIs) in kidneys from older donors. Hence, it is pivotal to shift the focus from prevention of rejection to preservation of graft function and prevention of over-immunosuppression in the elderly. The OPTIMIZE study will test the hypothesis that reduced CNI exposure in combination with everolimus will lead to better kidney transplant function, a reduced incidence of complications and improved health-related quality of life for kidney transplant recipients aged 65 years and older, compared to standard immunosuppression.

METHODS

This open label, randomized, multicenter clinical trial will include 374 elderly kidney transplant recipients (≥ 65 years) and consists of two strata. Stratum A includes elderly recipients of a kidney from an elderly deceased donor and stratum B includes elderly recipients of a kidney from a living donor or from a deceased donor < 65 years. In each stratum, subjects will be randomized to a standard, tacrolimus-based immunosuppressive regimen with mycophenolate mofetil and glucocorticoids or an adapted immunosuppressive regimen with reduced CNI exposure in combination with everolimus and glucocorticoids. The primary endpoint is 'successful transplantation', defined as survival with a functioning graft and an eGFR ≥ 30 ml/min per 1.73 m2 in stratum A and ≥ 45 ml/min per 1.73 m2 in stratum B, after 2 years, respectively.

CONCLUSIONS

The OPTIMIZE study will help to determine the optimal immunosuppressive regimen after kidney transplantation for elderly patients and the cost-effectiveness of this regimen. It will also provide deeper insight into immunosenescence and both subjective and objective outcomes after kidney transplantation in elderly recipients.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03797196 , registered January 9th, 2019. EudraCT: 2018-003194-10, registered March 19th, 2019.

Delayed graft function and rejection are risk factors for cytomegalovirus breakthrough infection in kidney transplant recipients

Breakthrough cytomegalovirus (CMV) disease during valganciclovir prophylaxis is rare but may cause significant morbidity and even mortality. In order to identify patients at increased risk the incidence of CMV disease was studied in a large population of renal transplant recipients who underwent a kidney transplantation in the Radboud University Medical Center between 2004 and 2015 (n = 1300). CMV disease occurred in 31/1300 patients. Multivariate binary linear regression analysis showed that delayed graft function (DGF) (p = 0.018) and rejection (p = 0.001) significantly and independently increased the risk of CMV disease, whereas CMV status did not. Valganciclovir prophylaxis was prescribed to 281/1300 (21.6%) high-risk patients (defined as CMV IgG-seronegative recipients receiving a kidney from a CMV IgG-seropositive donor (D+/R-)). Of these 281 patients, 51 suffered from DGF (18%). The incidence of breakthrough CMV disease in D + /R- patients with DGF was much higher than in those with immediate function (6/51 (11.8%) vs 2/230, (0.9%), p = 0.0006 Fisher's exact test), despite valganciclovir prophylaxis. This higher incidence of CMV disease could not be explained by a higher incidence of rejection (and associated anti-rejection treatment) in patients with DGF. D + /R- patients with DGF are at increased risk of developing CMV disease despite valganciclovir prophylaxis. These findings suggest that underexposure to ganciclovir occurs in patients with DGF. Prospective studies evaluating the added value of therapeutic drug monitoring to achieve target ganciclovir concentrations in patients with DGF are needed.

Long-term risks after kidney donation: how do we inform potential donors? A survey from DESCARTES and EKITA transplantation working groups

Background

Publications from the last decade have increased knowledge regarding long-term risks after kidney donation. We wanted to perform a survey to assess how transplant professionals in Europe inform potential kidney donors regarding long-term risks. The objectives of the survey were to determine how they inform donors and to what extent, and to evaluate the degree of variation.

Methods

All transplant professionals involved in the evaluation process were considered eligible, regardless of the type of profession. The survey was dispatched as a link to a web-based survey. The subjects included questions on demographics, the information policy of the respondent and the use of risk calculators, including the difference of relative and absolute risks and how the respondents themselves understood these risks.

Results

The main finding was a large variation in how often different long-term risks were discussed with the potential donors, i.e. from always to never. Eighty percent of respondents stated that they always discuss the risk of end-stage renal disease, while 56% of respondents stated that they always discuss the risk of preeclampsia. Twenty percent of respondents answered correctly regarding the relationship between absolute and relative risks for rare outcomes.

Conclusions

The use of written information and checklists should be encouraged. This may improve standardization regarding the information provided to potential living kidney donors in Europe. There is a need for information and education among European transplant professionals regarding long-term risks after kidney donation and how to interpret and present these risks.

Increased Plasma Heparanase Activity in COVID-19 Patients

Reports suggest a role of endothelial dysfunction and loss of endothelial barrier function in COVID-19. It is well established that the endothelial glycocalyx-degrading enzyme heparanase contributes to vascular leakage and inflammation. Low molecular weight heparins (LMWH) serve as an inhibitor of heparanase. We hypothesize that heparanase contributes to the pathogenesis of COVID-19, and that heparanase may be inhibited by LMWH. To test this hypothesis, heparanase activity and heparan sulfate levels were measured in plasma of healthy controls (n = 10) and COVID-19 patients (n = 48). Plasma heparanase activity and heparan sulfate levels were significantly elevated in COVID-19 patients. Heparanase activity was associated with disease severity including the need for intensive care, lactate dehydrogenase levels, and creatinine levels. Use of prophylactic LMWH in non-ICU patients was associated with a reduced heparanase activity. Since there is no other clinically applied heparanase inhibitor currently available, therapeutic treatment of COVID-19 patients with low molecular weight heparins should be explored.

Role of syndecan-1 in the interaction between dendritic cells and T cells

Syndecan-1 (Sdc-1) is a heparan sulfate proteoglycan that can bind cytokines and chemokines via its heparan sulfate side chains, and has immunomodulatory properties in experimental models. Sdc-1 expression has been reported on dendritic cells (DC) and T cells. The potential role of Sdc-1 in DC-T cell interaction has not been investigated yet. We postulate that Sdc-1 is involved in DC-T cell interaction and may influence graft survival in an allogeneic transplant model. Sdc-1 expression on bone marrow-derived DC and T cells was analyzed by flow cytometry. Unstimulated and LPS stimulated Sdc-1 deficient DC were evaluated in vitro for phenotype and stimulatory capacity in mixed lymphocyte reaction. Sdc-1 deficient T cells were evaluated for proliferative capacity and differentiation in a mixed lymphocyte reaction and a proliferation assay. Allograft survival was evaluated in a fully MHC mismatched heterotopic heart transplant model, with either Sdc-1 deficient donors or recipients. Sdc-1 was expressed on the cell surface of unstimulated and LPS matured DC. Sdc-1 deficiency had no effect on expression of co-stimulatory molecules, cytokine production or T cell stimulatory capacity as compared to WT DC. Sdc-1 expression was not detectable on WT T cells, although intracellular Sdc-1 expression could be demonstrated after ConA activation. Sdc-1 deficient T cells showed reduced proliferation upon DC or ConA stimulation and reduced IL-17 production upon ConA stimulation, compared to WT T cells. Sdc-1 deficiency of either allograft or recipient did not prolong allograft survival. In conclusion, Sdc-1 is expressed on the cell surface of DC, where its absence does not affect DC phenotype or T cell stimulatory capacity. Sdc-1 is intracellularly expressed in ConA activated T cells. Sdc-1 deficiency in T cells results in a reduced proliferative response in vitro, as induced by DC and ConA. Sdc-1 deficiency in donor or recipient does not affect allograft survival.

Pre-existing malignancies in renal transplant candidates-time to reconsider waiting times

Current proposals for waiting times for a renal transplant after malignant disease may not be appropriate. New data on malignancies in end-stage renal disease and recent diagnostic and therapeutic options should lead us to reconsider our current practice.

Long-term risks of kidney living donation: review and position paper by the ERA-EDTA DESCARTES working group

Two recent matched cohort studies from the USA and Norway published in 2014 have raised some concerns related to the long-term safety of kidney living donation. Further studies on the long-term risks of living donation have since been published. In this position paper, Developing Education Science and Care for Renal Transplantation in European States (DESCARTES) board members critically review the literature in an effort to summarize the current knowledge concerning long-term risks of kidney living donation to help physicians for decision-making purposes and for providing information to the prospective live donors. Long-term risk of end-stage renal disease (ESRD) can be partially foreseen by trying to identify donors at risk of developing ‘de novo’ kidney diseases during life post-donation and by predicting lifetime ESRD risk. However, lifetime risk may be difficult to assess in young donors, especially in those having first-degree relatives with ESRD. The study from Norway also found an increased risk of death after living donor nephrectomy, which became visible only after >15 years of post-donation follow-up. However, these findings are likely to be largely the result of an overestimation due to the confounding effect related to a family history of renal disease. DESCARTES board members emphasize the importance of optimal risk–benefit assessment and proper information to the prospective donor, which should also include recommendations on health-promoting behaviour post-donation.

Acetylated Histones in Apoptotic Microparticles Drive the Formation of Neutrophil Extracellular Traps in Active Lupus Nephritis

Objective

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the presence of autoantibodies against nuclear components. Lupus nephritis (LN) is the major cause of morbidity and mortality in patients with SLE. Central to the pathogenesis of SLE is the accumulation of cellular waste, especially apoptotic microparticles (MPs), which stimulates diverse immune reactions including the formation of neutrophil extracellular traps (NETs). In this study, we investigated the content of MPs from SLE patients with and without (active) LN, their capacity to stimulate NET release, and assessed the molecular mechanisms underlying MP-induced NETosis.

Methods

MPs from SLE patients with biopsy-proven active LN, remissive LN, without LN, and healthy controls were characterized by flow cytometry. Isolated neutrophils were exposed to MPs derived from either patient plasma or apoptotic human umbilical vein endothelial cells, and NET release was quantified by immunofluorescence imaging, spectrofluorometry or an in-house developed NET ELISA.

Results

MPs from SLE patients with active LN contain higher levels of acetylated chromatin compared to MPs from those with remissive LN, without LN, or healthy controls. MPs enriched in hyperacetylated chromatin are more potent in inducing NETosis when compared to MPs containing moderate acetylated chromatin. The release of NETs in response to MPs occurs rapidly in a concentration-dependent manner and proceeds independent from the formation of reactive oxygen species (ROS).

Conclusion

Our data suggest that MPs containing acetylated chromatin drive ROS-independent NET release in SLE patients with active LN, which may lead to the glomerular deposition of NETs and subsequent NET-driven LN.

Determinants of the Magnitude of Interaction Between Tacrolimus and Voriconazole/Posaconazole in Solid Organ Recipients

Administration of azole antifungals to tacrolimus-treated solid organ recipients results in a major drug-drug interaction characterized by increased exposure to tacrolimus. The magnitude of this interaction is highly variable but cannot currently be predicted. We performed a retrospective analysis of 126 solid organ recipients (95 lung, 31 kidney) co-treated with tacrolimus and voriconazole (n = 100) or posaconazole (n = 26). Predictors of the change in tacrolimus dose-corrected trough concentrations (C/D) between baseline and tacrolimus-azole co-therapy were assessed using linear mixed modeling. Patients were genotyped for relevant polymorphisms in CYP3A4, CYP3A5, MDR1, CYP2C19, POR, and UGT1A4. Tacrolimus C/D increased by a factor 5.0 ± 2.7 (range 1.0-20.2) for voriconazole and 4.4 ± 2.6 (range 0.9-18.0) for posaconazole, suggesting that a 66% dose reduction is insufficient for the majority of patients. Change in C/D was blunted in CYP3A5 expressors (estimated effect: -43%, p = 0.017) and affected by hematocrit (+8% per %, p = 0.004), baseline C/D (-14% per 100% increase, p < 0.001), and age (+1%, p = 0.008). However, the final model explained only 22% of interindividual variability in C/D change. In conclusion, CYP3A5 genotype and several clinical variables were identified as modulators of the tacrolimus-azole interaction, but these did not permit accurate predictions in individual patients.

NaCl cotransporter abundance in urinary vesicles is increased by calcineurin inhibitors and predicts thiazide sensitivity

Animal studies have shown that the calcineurin inhibitors (CNIs) cyclosporine and tacrolimus can activate the thiazide-sensitive NaCl cotransporter (NCC). A common side effect of CNIs is hypertension. Renal salt transporters such as NCC are excreted in urinary extracellular vesicles (uEVs) after internalization into multivesicular bodies. Human studies indicate that CNIs also increase NCC abundance in uEVs, but results are conflicting and no relationship with NCC function has been shown. Therefore, we investigated the effects of CsA and Tac on the abundance of both total NCC (tNCC) and phosphorylated NCC at Thr60 phosphorylation site (pNCC) in uEVs, and assessed whether NCC abundance in uEVs predicts the blood pressure response to thiazide diuretics. Our results show that in kidney transplant recipients treated with cyclosporine (n = 9) or tacrolimus (n = 23), the abundance of both tNCC and pNCC in uEVs is 4–5 fold higher than in CNI-free kidney transplant recipients (n = 13) or healthy volunteers (n = 6). In hypertensive kidney transplant recipients, higher abundances of tNCC and pNCC prior to treatment with thiazides predicted the blood pressure response to thiazides. During thiazide treatment, the abundance of pNCC in uEVs increased in responders (n = 10), but markedly decreased in non-responders (n = 8). Thus, our results show that CNIs increase the abundance of both tNCC and pNCC in uEVs, and these increases correlate with the blood pressure response to thiazides. This implies that assessment of NCC in uEVs could represent an alternate method to guide anti-hypertensive therapy in kidney transplant recipients.

Enhanced activation of dendritic cells by autologous apoptotic microvesicles in MRL/lpr mice

Introduction

Systemic lupus erythematosus is associated with a persistent circulation of modified autoantigen-containing apoptotic debris that might be capable of breaking tolerance. We aimed to evaluate apoptotic microvesicles obtained from lupus or control mice for the presence of apoptosis-associated chromatin modifications and for their capacity to stimulate dendritic cells (DC) from lupus and control mice.

Method

Apoptotic microvesicles were in vitro generated from splenocytes, and ex vivo isolated from plasma of both MRL/lpr lupus mice and normal BALB/c mice. Microvesicles were analyzed using flow cytometry. Bone marrow-derived (BM)-DC cultured from MRL/lpr or BALB/c mice were incubated with microvesicles and CD40 expression and cytokine production were determined as measure of activation.

Results

Microvesicles derived from apoptotic splenocytes or plasma of MRL/lpr mice contained more modified chromatin compared to microvesicles of BALB/c mice, and showed enhanced activation of DC, either from MRL/lpr or BALB/c mice, and consecutively an enhanced DC-mediated activation of splenocytes. The content of apoptosis-modified chromatin in microvesicles of apoptotic splenocytes correlated with their potency to induce interleukin-6 (IL-6) production by DC. Microvesicle-activated MRL/lpr DC showed a significant higher production of IL-6 and tumor growth factor-β (TGF-β) compared to BALB/c DC, and were more potent in the activation of splenocytes.

Conclusion

Apoptotic microvesicles from MRL/lpr mice are more potent activators of DC, and DC from MRL/lpr mice appear relatively more sensitive to activation by apoptotic microvesicles. Our findings indicate that aberrations at the level of apoptotic microvesicles and possibly DC contribute to the autoimmune response against chromatin in MRL/lpr mice.

Permanent acceptance of both cardiac and skin allografts using a mild conditioning regimen for the induction of stable mixed chimerism in mice

Patients who are receiving an organ transplant nowadays are sentenced to the life-long administration of immunosuppressive drugs, which have serious side effects. The reliable induction of donor-specific tolerance therefore remains a major goal in organ transplantation. Previously, we have developed a sublethal, non-myeloablative murine model in which permanent mixed, multilineage chimerism and donor-specific tolerance are established. Our model involves engraftment of fully allogeneic T cell depleted donor bone marrow cells in low dose irradiated and anti-CD3 treated major histocompatibility complex (MHC)-disparate recipient mice. To investigate whether vascularized organ grafts are accepted in our model, we performed heterotopic heart transplantations in our mixed chimeric mice. Chimeric mice permanently accepted hearts from the bone marrow donor (>130 days) and rapidly rejected third party-type allografts (median survival time 9 days). Untreated control recipient mice rejected both donor- and third party-type allografts. In addition, mice that accepted their cardiac grafts, donor-specific acceptance of skin grafts was observed. In conclusion, the establishment of stable mixed chimerism with this low-toxicity regimen resulted in permanent donor-specific acceptance of vascularized organ as well as skin grafts across a full MHC barrier.