Evaluation of severity of delayed graft function in kidney transplant recipients.

BACKGROUND: The most common definition of delayed graft function (DGF) relies on dialysis during the first week post-transplant and does not consider DGF severity. The impact of DGF severity on long-term graft outcome remains controversial. METHODS: We analysed 627 deceased-donor kidney transplant recipients (KTRs) transplanted in 2005-2015 at our centre for DGF severity, associated risk factors and long-term consequences of DGF. RESULTS: We found 349 (55.7%) KTRs with DGF, which were classified into four groups according to DGF duration (0-1, 2-7, 8-14, >14 days) and were compared with KTR with no DGF. A longer duration of DGF was associated with progressive worsening of 10-year death-censored graft survival {no DGF: 88.3% [95% confidence interval (CI) 82.4-94.2]; 0-1 day: 81.3% [95% CI 68.2-94.4], 2-7 days: 61.5% [95% CI 43.1.1-79.9], 8-14 days: 66.6% [95% CI 47.4-85.8], >14 days: 51.2% [95% CI 33-69.4]; P < 0.001}. In kidneys with a Kidney Donor Profile Index (KDPI) ≥85%, all DGF severity groups demonstrated reduced graft survival. However, in the <85% KDPI kidneys, only >14 days DGF duration showed worse outcomes. CONCLUSIONS: DGF had a duration-dependent effect on graft survival, which varied depending on the KDPI. Of note, 0- to 1-day DGF showed comparable results to no DGF in the whole cohort.

TBase - an Integrated Electronic Health Record and Research Database for Kidney Transplant Recipients.

TBase is an electronic health record (EHR) for kidney transplant recipients (KTR) combining automated data entry of key clinical data (e.g., laboratory values, medical reports, radiology and pathology data) via standardized interfaces with manual data entry during routine treatment (e.g., clinical notes, medication list, and transplantation data). By this means, a comprehensive database for KTR is created with benefits for routine clinical care and research. It enables both easy everyday clinical use and quick access for research questions with highest data quality. This is achieved by the concept of data validation in clinical routine in which clinical users and patients have to rely on correct data for treatment and medication plans and thereby validate and correct the clinical data in their daily practice. This EHR is tailored for the needs of transplant outpatient care and proved its clinical utility for more than 20 years at Charité - Universitätsmedizin Berlin. It facilitates efficient routine work with well-structured, comprehensive long-term data and allows their easy use for clinical research. To this point, its functionality covers automated transmission of routine data via standardized interfaces from different hospital information systems, availability of transplant-specific data, a medication list with an integrated check for drug-drug interactions, and semi-automated generation of medical reports among others. Key elements of the latest reengineering are a robust privacy-by-design concept, modularity, and hence portability into other clinical contexts as well as usability and platform independence enabled by HTML5 (Hypertext Markup Language) based responsive web design. This allows fast and easy scalability into other disease areas and other university hospitals. The comprehensive long-term datasets are the basis for the investigation of Machine Learning algorithms, and the modular structure allows to rapidly implement these into clinical care. Patient reported data and telemedicine services are integrated into TBase in order to meet future needs of the patients. These novel features aim to improve clinical care as well as to create new research options and therapeutic interventions.

The underestimated burden of monogenic kidney disease in adults waitlisted for kidney transplantation.

PURPOSE: Chronic kidney disease (CKD) is a major health-care burden. Increasing evidence suggests that a considerable proportion of patients are affected by a monogenic kidney disorder. METHODS: In this study, the kidney transplantation waiting list at the Charité was screened for patients with undetermined cause of CKD. By next-generation sequencing (NGS) we targeted all 600 genes described and associated with kidney disease or allied disorders. RESULTS: In total, 635 patients were investigated. Of these, 245 individuals had a known cause of CKD (38.5%) of which 119 had a proven genetic disease (e.g., ADPKD, Alport). The other 340 patients (53.5%) were classified as undetermined diagnosis, of whom 87 had kidney failure (KF) onset <40 years. To this latter group genetic testing was offered as well as to those patients (n = 29) with focal segmental glomerulosclerosis (FSGS) and all individuals (n = 21) suspicious for thrombotic microangiopathy (TMA) in kidney biopsy. We detected diagnostic variants in 26 of 126 patients (20.6%) of which 14 of 126 (11.1%) were pathogenic or likely pathogenic. In another 12 of 126 (9.5%) patients, variants of unknown significance (VUS) were detected. CONCLUSION: Our study demonstrates the diagnostic value of comprehensive genetic testing among patients with undetermined CKD.

De-novo malignancies after kidney transplantation: A long-term observational study.

BACKGROUND: De-novo malignancies after kidney transplantation represent one major cause for mortality after transplantation. However, most of the studies are limited due to small sample size, short follow-up or lack of information about cancer specific mortality. METHODS: This long-term retrospective analysis included all adult patients with complete follow-up that underwent kidney transplantation between 1995 and 2016 at our centre. All patients with diagnosis of malignancy excluding non-melanoma skin cancer (NMSC) were identified and a matched control group was assigned to the kidney transplant recipients with post-transplant malignancies. RESULTS: 1417 patients matched the inclusion criteria. 179 malignancies posttransplant were diagnosed in 154 patients (n = 21 with two, n = 2 patients with three different malignancies). Mean age at cancer diagnosis was 60.3±13.3 years. Overall incidence of de-novo malignancies except NMSC was 1% per year posttransplant. Renal cell carcinoma was the most common entity (n = 49, incidence 4.20 per 1000 patient years; cancer specific mortality 12%), followed by cancer of the gastro-intestinal tract (n = 30, 2.57; 50%), urinary system (n = 24, 2.06; 13%), respiratory system (n = 18, 1.54; 89%), female reproductive system (n = 15, 1.29; 13%), posttransplant lymphoproliferative disorders and haematological tumours (n = 14, 1.20; 21%), cancers of unknown primary (n = 7, 0.60 100%) and others (n = 22, 1.89; 27%). Male sex, re-transplantation and time on dialysis were associated with de-novo malignancies after transplantation. CONCLUSION: De-novo malignancies continue to be a serious problem after kidney transplantation. To improve long-term outcome after Kidney transplantation, prevention and cancer screening should be more tailored and intensified.

Analysis of Risk Factors and Long-Term Outcomes in Kidney Transplant Patients with Identified Lymphoceles.

The collection of lymphatic fluids (lymphoceles) is a frequent adverse event following renal transplantation. A variety of surgical and medical factors has been linked to this entity, but reliable data on risk factors and long-term outcomes are lacking. This retrospective single-center study included 867 adult transplant recipients who received a kidney transplantation from 2006 to 2015. We evaluated for patient and graft survival, rejection episodes, or detectable donor-specific antibodies (dnDSA) in patients with identified lymphoceles in comparison to controls. We identified 305/867 (35.2%) patients with lymphocele formation, of whom 72/867 (8.3%) needed intervention. Multivariate analysis identified rejection episode as an independent risk factor (OR 1.61, CI 95% 1.17-2.21, p = 0.003) for lymphocele formation, while delayed graft function was independently associated with symptomatic lymphoceles (OR 1.9, CI 95% 1.16-3.12, p = 0.011). Interestingly, there was no difference in detectable dnDSA between groups with a similar graft and patient survival in all groups after 10 years. Lymphoceles frequently occur after transplantation and were found to be independently associated with rejection episodes, while symptomatic lymphoceles were associated with delayed graft function in our cohort. As both are inflammatory processes, they might play a causative role in the formation of lymphoceles. However, development or intervention of lymphoceles did not lead to impaired graft survival in the long-term.

Influence of pretransplant class I and II non-donor-specific anti-HLA immunization on immunologic outcome and graft survival in kidney transplant recipients.

BACKGROUND: Anti-HLA immunization determined by Panel Reactive Antibody (PRA) is known to have a negative impact on patient and graft survival. The predictive value of peak PRA (pPRA) on immunologic outcome, however, and the individual effects of anti-HLA class I and II antibodies remain uncertain. METHODS: The influence of HLA immunization on immunologic outcome parameters and graft survival was investigated in 1150 adult patients without pretransplant donor-specific antibodies (DSA) and in a subgroup of elderly kidney recipients aged ≥ 65 (n = 264). Anti-HLA immunization was defined as a pPRA > 0%. We investigated the influence of class I and II pPRA by dividing all kidney recipients into four pPRA groups (0%, 1-20%, 21-80%, >80%). RESULTS: Patients with non-donor-specific pretransplant anti-HLA immunization were at a higher risk for developing de novo DSA (49.9% vs. 18.7% p < 0.001), antibody mediated rejections (ABMR) (15.7% vs. 5.1%; p < 0.001), had a poorer death censored graft survival (69.2% vs. 86.2%; p < 0.001) and a higher decline of the calculated GFR. In elderly patients anti-HLA immunization only had a significant influence on the development of DSA (40.5% vs. 27.4%; p = 0.004). A multivariate model adjusted for all relevant factors revealed only class I but not class II pretransplant HLA immunization as a significant independent risk factor for de novo DSA, ABMR and death censored graft loss (HR 2.76, p < 0.001, HR 4.16, p < 0.001 and HR 2.07, p < 0.001, respectively). CONCLUSION: Mainly non-donor-specific pretransplant HLA class I immunization is an independent risk factor for the development of de novo DSA, ABMR and graft loss.

Intensive monitoring of post filter ionized calcium concentrations during CVVHD with regional citrate anticoagulation: A retrospective study.

BACKGROUND: The aim of the present study was to assess the predictive value of post-filter ionized calcium (pfCa) levels for filter-clotting during continuous veno-venous hemodialysis (CVVHD) with regional citrate anticoagulation (RCA). METHODS: Retrospective analysis of a database derived from 6 intensive care units (ICU) at a university hospital. During the 3-year period 1070 patients were treated with RCA-CVVHD with a citrate starting dose of 4 mmol/L blood and a target-range for pfCa of 0.25-0.35 mmol/L. RESULTS: The pfCa concentrations at RCA-CVVHD initiation were within the target range in 69.7% of patients. Within 12 h the fraction of patients with pfCa above target-range decreased significantly from 13.1% to 7.8% (p < .001). There was no significant difference in filter survival between patients with a pfCa initially below, within, or above the target-range (83.7%, 89.5% and 90.4%; p = .228) and no significant correlation between the last pfCa and the incidence of filter clotting (rho 0.018, p = .572 and -0.054, p = .104; respectively). CONCLUSIONS: CVVHD with a citrate starting dose of 4 mmol/L blood resulted in a pfCa within target in the majority of patients. The observation that pfCa was not associated with the incidence of circuit clotting suggests that less frequent measurements of pfCA might be safe.

Preformed Donor-Specific HLA Antibodies in Living and Deceased Donor Transplantation: A Multicenter Study.

BACKGROUND AND OBJECTIVES: The prognostic value of preformed donor-specific HLA antibodies (DSA), which are only detectable by sensitive methods, remains controversial for kidney transplantation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The outcome of 4233 consecutive kidney transplants performed between 2012 and 2015 in 18 German transplant centers was evaluated. Most centers used a stepwise pretransplant antibody screening with bead array tests and differentiation of positive samples by single antigen assays. Using these screening results, DSA against HLA-A, -B, -C, -DRB1 and -DQB1 were determined. Data on clinical outcome and possible covariates were collected retrospectively. RESULTS: Pretransplant DSA were associated with lower overall graft survival, with a hazard ratio of 2.53 for living donation (95% confidence interval [95% CI], 1.49 to 4.29; P<0.001) and 1.59 for deceased donation (95% CI, 1.21 to 2.11; P=0.001). ABO-incompatible transplantation was associated with worse graft survival (hazard ratio, 2.09; 95% CI, 1.33 to 3.27; P=0.001) independent from DSA. There was no difference between DSA against class 1, class 2, or both. Stratification into DSA <3000 medium fluorescence intensity (MFI) and DSA ≥3000 MFI resulted in overlapping survival curves. Therefore, separate analyses were performed for 3-month and long-term graft survival. Although DSA <3000 MFI tended to be associated with both lower 3-month and long-term transplant survival in deceased donation, DSA ≥3000 MFI were only associated with worse long-term transplant survival in deceased donation. In living donation, only strong DSA were associated with reduced graft survival in the first 3 months, but both weak and strong DSA were associated with reduced long-term graft survival. A higher incidence of antibody-mediated rejection within 6 months was only associated with DSA ≥3000 MFI. CONCLUSIONS: Preformed DSA were associated with an increased risk for graft loss in kidney transplantation, which was greater in living than in deceased donation. Even weak DSA <3000 MFI were associated with worse graft survival. This association was stronger in living than deceased donation.

Validation of the Living Kidney Donor Profile Index in a European cohort and comparison of long-term outcomes with US results.

BACKGROUND: Recently, a risk index for living donor kidney (LDK) transplantation [living kidney donor profile index (LKDPI)] was proposed to compare LDKs with each other and with deceased donor kidneys (DDKs). Until now, the LKDPI has not been validated externally. METHODS: This long-term retrospective analysis included 1305 consecutive adult kidney transplant recipients who were transplanted 2000-16 in our centre. The Kidney Donor Profile Index (KDPI) was calculated in 889 DDKs and the LKDPI in 416 LDKs. Outcome was followed over a median of 6.5 years. RESULTS: The median LKDPI was 17 and the median KDPI was 69, with a high proportion of donor kidneys with a very high KDPI (40% KDPI ≥ 80). Categorization of LDK into LKDPI quartiles (LKDPI -45-3, 3-17, 17-33, 33-90) revealed a significant difference in death-censored graft survival. Comparing corresponding subgroups of the LKDPI and KDPI (LKDPI/KDPI 0-20 or 20-40) showed comparable graft survival. A multivariate analysis adjusting for relevant recipient factors revealed the KDPI [hazard ratio (HR) 1.21; P < 0.001) and LKDPI (HR 1.15; P = 0.049) as significant independent predictors of graft loss. Time-to-event receiver operating characteristic analyses for graft survival demonstrated lower predictive discrimination of the LKDPI [area under the curve (AUC) 0.55] compared with the KDPI (AUC 0.66). The 10-year graft survival of LDK recipients was inferior in the USA compared with our centre (79% versus 84%). CONCLUSIONS: These results provide external validation of the LKDPI to predict death-censored graft survival and confirm comparability of the LKDPI with the KDPI to discriminate post-transplant outcome.

High frequency of valganciclovir underdosing for cytomegalovirus prophylaxis after renal transplantation.

BACKGROUND: The correct valganciclovir dose for cytomegalovirus (CMV) prophylaxis depends on renal function estimated by the Cockcroft-Gault (CG) estimated creatinine clearance (CG-CrCl) formula. Patients with delayed or rapidly changing graft function after transplantation (tx) will need dose adjustments. METHODS: We performed a retrospective investigation of valganciclovir dosing in renal transplant patients receiving CMV prophylaxis between August 2003 and August 2011, and analysed valganciclovir dosing, CG-CrCl, CMV viraemia (CMV-PCR <750 copies/mL), leucopenia (<3500/µL) and neutropenia (<1500/µL) in the first year post-transplant. On Days 30 and 60 post-transplant, dosing pattern in relation to estimated creatinine clearance was analysed regarding CMV viraemia, leucopenia and neutropenia. RESULTS: Six hundred and thirty-five patients received valganciclovir prophylaxis that lasted 129 ± 68 days with a mean dose of 248 ± 152 mg/day of whom 112/635 (17.7%) developed CMV viraemia, 166/635 (26.1%) leucopenia and 48/635 (7.6%) neutropenia. CMV resistance within 1 year post-transplant was detected in three patients. Only 137/609 (22.6%) patients received the recommended dose, while n = 426 (70.3%) were underdosed and n = 43 (7.1%) were overdosed at Day 30 post-tx. Risk factors for CMV viraemia were donor positive D (+)/receptor negative R (-) status and short prophylaxis duration, but not low valganciclovir dose. Risk factors for developing leucopenia were D+/R- status and low renal function. No significant differences in dosing frequency were observed in patients developing neutropenia or not (P = 0.584). CONCLUSION: Most patients do not receive the recommended valganciclovir dose. Despite obvious underdosing in a large proportion of patients, effective prophylaxis was maintained and it was not associated as a risk factor for CMV viraemia or leucopenia.

Assessment of the Kidney Donor Profile Index in a European cohort.

Background: Recently, transplant societies have had to change their allocation policies to counter global organ shortages. However, strategies differ significantly and long-term outcomes and cross-regional applicability remain to be evaluated. Methods: Therefore, we retrospectively analysed the Kidney Donor Profile Index (KDPI) of 987 adult kidney transplants at our centre using data from the Organ Procurement and Transplantation Network (OPTN) as a reference. Results: In our cohort, the median KDPI was 66%, with a higher proportion of >85% KDPI kidneys compared with the US cohort (32.3% versus 9.2%). Among elderly patients (≥65 years of age), 62% received >95% KDPI kidneys, which were primarily allocated within the Eurotransplant Senior Program (ESP). After 10 years, the rate of death-censored graft survival was 70.5%. Recipients of >85% KDPI kidneys were significantly older, demonstrating higher mortality, poorer graft survival and lower estimated glomerular filtration rate. Patients receiving ≥99% KDPI kidneys had a satisfactory 5-year death-censored graft survival (72.9%). The 5-year survival rate of patients living with a functioning graft exceeded the matched OPTN data in the whole KDPI range, despite a higher proportion of elderly recipients. Multivariate analysis revealed KDPI as an independent risk factor for graft loss (hazard ratio 1.14/10%, P < 0.001), although C-statistics of 0.62 indicated limited discriminative ability for individuals. Conclusion: The analysis demonstrated KDPI as a potentially useful tool for donor quality assessment in a European cohort. Most importantly, our analysis revealed acceptable outcomes even for very high KDPI kidneys.

Hyperlactatemia, Lactate Kinetics and Prediction of Citrate Accumulation in Critically Ill Patients Undergoing Continuous Renal Replacement Therapy With Regional Citrate Anticoagulation.

OBJECTIVES: Citrate accumulation is a major complication of regional citrate anticoagulation during continuous renal replacement therapy. We studied the prediction of citrate accumulation during continuous veno-venous hemodialysis with regional citrate anticoagulation by initial lactate concentrations and lactate kinetics. DESIGN: A retrospective follow-up analysis from a cohort of critically ill patients. SETTING: Mixed medical-surgical ICUs at a university hospital. PATIENTS: All adult patients with acute kidney injury and treated with regional citrate anticoagulation-continuous veno-venous hemodialysis during a 3-year period (n = 1,070) were included in this retrospective study and screened for metabolic signs of citrate accumulation. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The frequency of citrate accumulation during the first 48 hours of therapy was 2.26%. In patients with initial normal lactate (< 2.2 mmol/L), elevated lactate (≥ 2.2 to < 4 mmol/L), or severe hyperlactatemia (≥ 4 mmol/L), the frequency of citrate accumulation was 0.77%, 2.70%, and 6.33%, respectively. Receiver operating characteristics-area under the curve of initial lactate concentration was 0.789 for the prediction of citrate accumulation. Optimal cutoff from receiver operating characteristics (2.39 mmol/L) showed strong negative prediction (99.28%), but weak positive prediction (5.21%). The slope intercept of lactate kinetics over 48 hours was positive and significantly higher in patients with citrate accumulation compared to those without (+0.2 vs -0.006 mmol/L/hr; p < 0.001). In patients with initial severe hyperlactatemia (≥ 4 mmol/L), the median calculated lactate clearance at 6, 12, and 18 hours was 24.0%, 48.1%, and 59.4% in the nonaccumulation group. These clearance rates were significantly higher at each time-point compared to patients with citrate accumulation (-9.8%, -20.5%, and 2.3%, respectively; p < 0.001 for each time-point). The highest receiver operating characteristics-area under the curve for citrate accumulation was observed for 12-hour values of lactate clearance (area under the curve = 0.839; 95% CI, 0.751-0.927) with an optimal cut-off value of 24.3%. CONCLUSIONS: Risk of citrate accumulation during regional citrate anticoagulation in a well-selected cohort of patients is low even in case of initial severe hyperlactatemia. Lactate kinetics rather than initially elevated lactate concentration should be considered in assessing the risk of citrate accumulation.

A novel tool for the identification of correlations in medical data by faceted search.

This work focuses on the integration of multifaceted extensive data sets (e.g. laboratory values, vital data, medications) and partly unstructured medical data such as discharge letters, diagnostic reports, clinical notes etc. in a research database. Our main application is an integrated faceted search in nephrology based on information extraction results. We describe the details of the application of transplant medicine and the resulting technical architecture of the faceted search application.

Anti-thymocyte globulins in kidney transplantation: focus on current indications and long-term immunological side effects.

Antithymocyte globulins (ATGs) are part of the immunosuppression arsenal currently used by clinicians to prevent or treat acute rejection in solid organ transplantation. ATG is a mixture of non-specific anti-lymphocyte immunoglobulins targeting not only T cell subsets but also several other immune and non-immune cells, rendering its precise immunoglobulin composition difficult to appreciate or to compare from one preparation to another. Furthermore, several mechanisms of action have been described. Taken together, this probably explains the efficacy and the side effects associated with this drug. Recent data suggest a long-term negative impact on allograft and patient outcomes, pointing out the need to better characterize the potential toxicity and the benefit-risk balance associated to this immunosuppressive therapy within large clinical trials.

Clinical Outcome of Patients With De Novo C1q-Binding Donor-Specific HLA Antibodies After Renal Transplantation.

BACKGROUND: De novo donor specific anti-HLA antibodies (dnDSA) may cause graft loss in renal transplant recipients. The capability to bind the complement may help to stratify the risk for inferior outcomes associated with dnDSA. We developed a modified C1q-binding assay and hypothesized that C1q-binding dnDSA could differentiate between indolent and harmful dnDSA causing antibody-mediated rejection (AMR) and graft loss. METHODS: We retrospectively identified 59 renal transplant recipients who developed dnDSA and had serum available and complete follow-up. All patients were analyzed for C1q-binding dnDSA at the time of dnDSA detection, and 1-year later or at time of AMR. AMR-positive patients were also tested 6 to 12 months before the event if IgG dnDSA was present. RESULTS: Thirty-seven of 59 dnDSA patients developed AMR during 5.9 ± 3.1 years follow-up. AMR-positive patients had more dnDSA with a significant higher frequency of class I, a higher frequency and a higher mean fluorescence intensity value of C1q-dnDSA at all time-points. Death-censored AMR-free and allograft survivals were significantly lower in C1q-dnDSA patients. In multivariate analysis, C1q-dnDSA was an independent risk factor for AMR. CONCLUSIONS: C1q-binding dnDSA is associated with inferior outcomes, yet not in all patients. Nevertheless, C1q-dnDSA was shown to be an independent risk factor of AMR and graft loss and may be a useful tool to stratify the immunological risk for AMR.

Improved Left Ventricular Structure and Function After Successful Kidney Transplantation.

BACKGROUND/AIMS: Cardiac changes observed in chronic kidney disease patients are of multifactorial origin including chronic uremia, hemodynamics or inflammation. Restoration of renal function by kidney transplantation (KTX) may reverse cardiac changes. Novel echocardiographic methods such as speckle tracking echocardiography (STE) allow early and sensitive detection of subtle changes of cardiac parameters. We evaluated changes of cardiac structure and function after KTX by advanced echocardiographic modalities. METHODS: Thirty-one KTX recipients (female n=11) were evaluated by medical examination, laboratory testing and echocardiography before and after KTX (median follow-up 19 months). Left ventricular (LV) and right ventricular (RV) diameters and function were assessed by echocardiographic standard parameters. Longitudinal 2D strain of the LV (GLPS) and left atrium (LA) was determined by 2D STE. RESULTS: After KTX, median serum creatinine level was 1.3 mg/dl (IQR, 1.2-1.5). Systolic blood pressure decreased significantly after KTX. Echocardiography showed a significant reduction in LV end-diastolic septal and posterior wall thickness and LV mass index after KTX, which was accompanied by an improvement of GLPS. There were no relevant changes in parameters of LA (reservoir, conduit or contractile) function, LV diastolic or RV function after KTX. CONCLUSION: LV hypertrophy reversed after successful KTX and was accompanied by an improvement in longitudinal LV function as assessed by STE. Diastolic function and STE-derived LA function parameters did not change significantly after KTX.

Immunologic outcome in elderly kidney transplant recipients: is it time for HLA-DR matching?

BACKGROUND: The Eurotransplant Senior Program (ESP) neglects HLA matching for elderly (≥65 years) kidney transplant recipients (KTR). Few data regarding the influence of DR matching on clinical and immunologic outcome in elderly KTR exist. METHODS: This retrospective long-term observational study included 244 elderly out of n = 972 adult KTR between 2004 and 2014. Data analysis included patient and graft survival, biopsy-proven rejections [T-cell-mediated rejections (TCMR) and antibody-mediated rejections] and development of de novo donor-specific HLA antibodies (DSA). Outcome data were assessed over a maximum period of 10 years. RESULTS: Due to the nature of the ESP, elderly KTR showed significantly more HLA mismatches, shorter time on dialysis and shorter cold ischaemia time. Elderly KTR had significantly worse graft and patient survival, and after 7 years, the rate of de novo DSA (33 versus 25%, P = 0.034) and TCMR (39 versus 27%, P < 0.001) was significantly higher compared with younger KTR. Multivariate analysis identified donor age, delayed graft function and HLA-DR mismatches as independent risk factors for TCMR. Within the group of elderly KTR, HLA-DR mismatches were associated with a significantly higher incidence of TCMR and development of de novo DSA. Occurrence of TCMR and de novo DSA in elderly KTR resulted in significantly worse graft survival. CONCLUSIONS: In elderly KTR, HLA-DR mismatches are independent risk factors for TCMR and the development of all classes of de novo DSA, both of which significantly impair graft survival. Introduction of HLA-DR matching in elderly KTR might significantly improve immunologic and overall outcome.