HLA sensitization is associated with an increased risk of primary graft dysfunction after heart transplantation

Primary graft dysfunction (PGD) is a leading cause of early morbidity and mortality following heart transplantation (HT). We sought to determine the association between pretransplant human leukocyte antigen (HLA) sensitization, as measured using the calculated panel reactive antibody (cPRA) value, and the risk of PGD.

METHODS

Consecutive adult HT recipients (n = 596) from 1/2015 to 12/2019 at 2 US centers were included. Severity of PGD was based on the 2014 International Society for Heart and Lung Transplantation consensus statement. For each recipient, unacceptable HLA antigens were obtained and locus-specific cPRA (cPRA-LS) and pre-HT donor-specific antibodies (DSA) were assessed.

RESULTS

Univariable logistic modeling showed that peak cPRA-LS for all loci and HLA-A was associated with increased severity of PGD as an ordinal variable (all loci: OR 1.78, 95% CI: 1.01-1.14, p = 0.025, HLA-A: OR 1.14, 95% CI: 1.03-1.26, p = 0.011). Multivariable analysis showed peak cPRA-LS for HLA-A, recipient beta-blocker use, total ischemic time, donor age, prior cardiac surgery, and United Network for Organ Sharing status 1 or 2 were associated with increased severity of PGD. The presence of DSA to HLA-B was associated with trend toward increased risk of mild-to-moderate PGD (OR 2.56, 95% CI: 0.99-6.63, p = 0.053), but DSA to other HLA loci was not associated with PGD.

CONCLUSIONS

Sensitization for all HLA loci, and specifically HLA-A, is associated with an increased severity of PGD. These factors should be included in pre-HT risk stratification to minimize the risk of PGD.

Identification of potential necroinflammation-associated necroptosis-related biomarkers for delayed graft function and renal allograft failure: a machine learning-based exploration in the framework of predictive, preventive, and personalized medicine

Delayed graft function (DGF) is one of the key post-operative challenges for a subset of kidney transplantation (KTx) patients. Graft survival is significantly lower in recipients who have experienced DGF than in those who have not. Assessing the risk of chronic graft injury, predicting graft rejection, providing personalized treatment, and improving graft survival are major strategies for predictive, preventive, and personalized medicine (PPPM/3PM) to promote the development of transplant medicine. However, since PPPM aims to accurately identify disease by integrating multiple omics, current methods to predict DGF and graft survival can still be improved. Renal ischemia/reperfusion injury (IRI) is a pathological process experienced by all KTx recipients that can result in varying occurrences of DGF, chronic rejection, and allograft failure depending on its severity. During this process, a necroinflammation-mediated necroptosis-dependent secondary wave of cell death significantly contributes to post-IRI tubular cell loss. In this article, we obtained the expression matrices and corresponding clinical data from the GEO database. Subsequently, nine differentially expressed necroinflammation-associated necroptosis-related genes (NiNRGs) were identified by correlation and differential expression analysis. The subtyping of post-KTx IRI samples relied on consensus clustering; the grouping of prognostic risks and the construction of predictive models for DGF (the area under the receiver operating characteristic curve (AUC) of the internal validation set and the external validation set were 0.730 and 0.773, respectively) and expected graft survival after a biopsy (the internal validation set's 1-year AUC: 0.770; 2-year AUC: 0.702; and 3-year AUC: 0.735) were based on the least absolute shrinkage and selection operator regression algorithms. The results of the immune infiltration analysis showed a higher infiltration abundance of myeloid immune cells, especially neutrophils, macrophages, and dendritic cells, in the cluster A subtype and prognostic high-risk groups. Therefore, in the framework of PPPM, this work provides a comprehensive exploration of the early expression landscape, related pathways, immune features, and prognostic impact of NiNRGs in post-KTx patients and assesses their capabilities as.predictors of post-KTx DGF and graft loss,targets of the vicious loop between regulated tubular cell necrosis and necroinflammation for targeted secondary and tertiary prevention, andreferences for personalized immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-023-00320-w.

Seeking Standardized Definitions for HLA-incompatible Kidney Transplants: A Systematic Review

BACKGROUND

There is no standard definition for "HLA incompatible" transplants. For the first time, we systematically assessed how HLA incompatibility was defined in contemporary peer-reviewed publications and its prognostic implication to transplant outcomes.

METHODS

We combined 2 independent searches of MEDLINE, EMBASE, and the Cochrane Library from 2015 to 2019. Content-expert reviewers screened for original research on outcomes of HLA-incompatible transplants (defined as allele or molecular mismatch and solid-phase or cell-based assays). We ascertained the completeness of reporting on a predefined set of variables assessing HLA incompatibility, therapies, and outcomes. Given significant heterogeneity, we conducted narrative synthesis and assessed risk of bias in studies examining the association between death-censored graft failure and HLA incompatibility.

RESULTS

Of 6656 screened articles, 163 evaluated transplant outcomes by HLA incompatibility. Most articles reported on cytotoxic/flow T-cell crossmatches (n = 98). Molecular genotypes were reported for selected loci at the allele-group level. Sixteen articles reported on epitope compatibility. Pretransplant donor-specific HLA antibodies were often considered (n = 143); yet there was heterogeneity in sample handling, assay procedure, and incomplete reporting on donor-specific HLA antibodies assignment. Induction (n = 129) and maintenance immunosuppression (n = 140) were frequently mentioned but less so rejection treatment (n = 72) and desensitization (n = 70). Studies assessing death-censored graft failure risk by HLA incompatibility were vulnerable to bias in the participant, predictor, and analysis domains.

CONCLUSIONS

Optimization of transplant outcomes and personalized care depends on accurate HLA compatibility assessment. Reporting on a standard set of variables will help assess generalizability of research, allow knowledge synthesis, and facilitate international collaboration in clinical trials.

Pre-transplant angiotensin II receptor type I antibodies in pediatric renal transplant recipients: An observational cohort study

BACKGROUND

The role of angiotensin II type 1 receptor antibodies (AT1R-Ab) in pediatric renal transplantation is unclear. Here, we evaluated pre-transplant AT1R-Ab on transplant outcomes in the first 5 years. Secondary analysis compared pre-transplant AT1R-Ab levels by age.

METHODS

Thirty-six patients, 2-20 years old, were divided into two groups: pre-transplant AT1R-Ab- (<17 U/ml; n = 18) and pre-transplant AT1R-Ab+ (≥17 U/ml; n = 18). eGFR was determined at 6-month, 1-, 2-, and 4-year post-transplant. Allograft biopsies were performed in the setting of strong HLA-DSA (MFI > 10 000), AT1R-Ab ≥17 U/ml, and/or elevated creatinine.

RESULTS

Mean age in pre-transplant AT1R-Ab- was 13.3 years vs. 11.0 in pre-transplant AT1R-Ab+ (p = 0.16). At 6 months, mean eGFR was 111.3 ml/min/1.73 m² in pre-transplant AT1R-Ab- vs. 100.2 in pre-transplant AT1R-Ab + at 1 year, 103.6 ml/min/1.73 m² vs. 100.5; at 2 years, 98.9 ml/min/1.73 m² vs. and 93.7; at 4 years, 72.6 ml/min/1.73 m² vs. 80.9. 11/36 patients had acute rejection (6 in pre-transplant AT1R-Ab-, 5 in pre-transplant AT1R-Ab + ). There was no difference in rejection rates. All 6 subjects with de novo HLA-DSA and AT1R-Ab ≥17 U/ml at the time of biopsy experienced rejection. Mean age in those with the AT1R-Ab ≥40 U/ml was 10.0 years vs. 13.2 in those <40 U/ml (p = 0.07).

CONCLUSION

In our small cohort, pre-transplant AT1R-Ab ≥17 U/ml was not associated with reduced graft function or rejection. The pathogenicity of pre-transplant AT1R-Ab in pediatric kidney transplantation requires further investigation.

Safety and Efficacy of a Steroid Avoidance Immunosuppression Regimen in Renal Transplant Patients With De Novo or Preformed Donor-Specific Antibodies: A Single-Center Study

Although interest in the role of donor-specific antibodies (DSAs) in kidney transplant rejection, graft survival, and histopathological outcomes is increasing, their impact on steroid avoidance or minimization in renal transplant populations is poorly understood. Primary outcomes of graft survival, rejection, and histopathological findings were assessed in 188 patients who received transplants between 2012 and 2015 at the Scripps Center for Organ Transplantation, which follows a steroid avoidance protocol. Analyses were performed using data from the United Network for Organ Sharing. Cohorts included kidney transplant recipients with de novo DSAs (dnDSAs; n = 27), preformed DSAs (pfDSAs; n = 15), and no DSAs (nDSAs; n = 146). Median time to dnDSA development (classes I and II) was shorter (102 days) than in previous studies. Rejection of any type was associated with DSAs to class I HLA (P < .05) and class II HLA (P < .01) but not with graft loss. Although mean fluorescence intensity (MFI) independently showed no association with rejection, an MFI >5000 showed a trend toward more antibody-mediated rejection (P < .06), though graft loss was not independently associated. Banff chronic allograft nephropathy scores and a modified chronic injury score were increased in the dnDSA cohort at 6 months, but not at 2 years (P < .001 and P < .08, respectively). Our data suggest that dnDSAs and pfDSAs impact short-term rejection rates but do not negatively impact graft survival or histopathological outcomes at 2 years. Periodic protocol post-transplant DSA monitoring may preemptively identify patients who develop dnDSAs who are at a higher risk for rejection.

Posttransplant Outcomes for cPRA-100% Recipients Under the New Kidney Allocation System

BACKGROUND

There is concern in the transplant community that outcomes for the most highly sensitized recipients might be poor under Kidney Allocation System (KAS) high prioritization.

METHODS

To study this, we compared posttransplant outcomes of 525 pre-KAS (December 4, 2009, to December 3, 2014) calculated panel-reactive antibodies (cPRA)-100% recipients to 3026 post-KAS (December 4, 2014, to December 3, 2017) cPRA-100% recipients using SRTR data. We compared mortality and death-censored graft survival using Cox regression, acute rejection, and delayed graft function (DGF) using logistic regression, and length of stay (LOS) using negative binomial regression.

RESULTS

Compared with pre-KAS recipients, post-KAS recipients were allocated kidneys with lower Kidney Donor Profile Index (median 30% versus 35%, P < 0.001) but longer cold ischemic time (CIT) (median 21.0 h versus 18.6 h, P < 0.001). Compared with pre-KAS cPRA-100% recipients, those post-KAS had higher 3-year patient survival (93.6% versus 91.4%, P = 0.04) and 3-year death-censored graft survival (93.7% versus 90.6%, P = 0.005). The incidence of DGF (29.3% versus 29.2%, P = 0.9), acute rejection (11.2% versus 11.7%, P = 0.8), and median LOS (5 d versus 5d, P = 0.2) were similar between pre-KAS and post-KAS recipients. After accounting for secular trends and adjusting for recipient characteristics, post-KAS recipients had no difference in mortality (adjusted hazard ratio [aHR]: 0.861.623.06, P = 0.1), death-censored graft failure (aHR: 0.521.001.91, P > 0.9), DGF (adjusted odds ratio [aOR]: 0.580.861.27, P = 0.4), acute rejection (aOR: 0.610.941.43, P = 0.8), and LOS (adjusted LOS ratio: 0.981.161.36, P = 0.08).

CONCLUSIONS

We did not find any statistically significant worsening of outcomes for cPRA-100% recipients under KAS, although longer-term monitoring of posttransplant mortality is warranted.

Outcomes of cPRA 100% deceased donor kidney transplant recipients under the new Kidney Allocation System: A single-center cohort study

In light of changes in donor/recipient case-mix and increased cold ischemia times under the Kidney Allocation System (KAS), there is some concern that cPRA 100% recipients might be doing poorly under KAS. We used granular, single-center data on 109 cPRA 100% deceased donor kidney transplant (DDKT) recipients to study post-KAS posttransplant outcomes not readily available in national registry data. We found that 3-year patient (96.4%) and death-censored graft survival (96.8%) was excellent. We also found that cPRA 100% recipients had a relatively low incidence of T cell-mediated rejection (9.2%) and antibody-mediated rejection (AMR) (13.8%). T cell-mediated rejection episodes tended to be relatively mild-50% (5 episodes) were grade 1, 50% (5 episodes) were grade 2, and none were grade 3. Only 1 episode was associated with graft loss, but this was in the context of a mixed rejection. Although only 15 recipients (13.8%) developed an AMR episode, 2 of these were associated with a graft loss. Despite the rejection episodes, the vast majority of recipients had excellent graft function 3 years posttransplant (median serum creatinine 1.5 mg/dL). In conclusion, cPRA 100% DDKT recipients are doing well under KAS, although every effort should be made to prevent AMR to ensure long-term outcomes remain excellent.

Pre-transplant HLA Antibodies and Delayed Graft Function in the Current Era of Kidney Transplantation

Delayed graft function (DGF) occurs in a significant proportion of deceased donor kidney transplant recipients and was associated with graft injury and inferior clinical outcome. The aim of the present multi-center study was to identify the immunological and non-immunological predictors of DGF and to determine its influence on outcome in the presence and absence of human leukocyte antigen (HLA) antibodies. 1,724 patients who received a deceased donor kidney transplant during 2008–2017 and on whom a pre-transplant serum sample was available were studied. Graft survival during the first 3 post-transplant years was analyzed by multivariable Cox regression. Pre-transplant predictors of DGF and influence of DGF and pre-transplant HLA antibodies on biopsy-proven rejections in the first 3 post-transplant months were determined by multivariable logistic regression. Donor age ≥50 years, simultaneous pre-transplant presence of HLA class I and II antibodies, diabetes mellitus as cause of end-stage renal disease, cold ischemia time ≥18 h, and time on dialysis >5 years were associated with increased risk of DGF, while the risk was reduced if gender of donor or recipient was female or the reason for death of donor was trauma. DGF alone doubled the risk for graft loss, more due to impaired death-censored graft than patient survival. In DGF patients, the risk of death-censored graft loss increased further if HLA antibodies (hazard ratio HR=4.75, P < 0.001) or donor-specific HLA antibodies (DSA, HR=7.39, P < 0.001) were present pre-transplant. In the presence of HLA antibodies or DSA, the incidence of biopsy-proven rejections, including antibody-mediated rejections, increased significantly in patients with as well as without DGF. Recipients without DGF and without biopsy-proven rejections during the first 3 months had the highest fraction of patients with good kidney function at year 1, whereas patients with both DGF and rejection showed the lowest rate of good kidney function, especially when organs from ≥65-year-old donors were used. In this new era of transplantation, besides non-immunological factors, also the pre-transplant presence of HLA class I and II antibodies increase the risk of DGF. Measures to prevent the strong negative impact of DGF on outcome are necessary, especially during organ allocation for presensitized patients.

Differential Impact of Delayed Graft Function in Deceased Donor Renal Transplant Recipients With and Without Donor-specific HLA-antibodies

BACKGROUND

Delayed graft function (DGF) and pretransplant donor-specific HLA-antibodies (DSA) are both regarded as risk factors for rejection and lower graft survival. However, the combined impact of DGF and DSA has not been studied in detail.

METHODS

We investigated 375 deceased donor kidney transplantations, which had DSA assignment by single-antigen bead technology and which had surveillance biopsies at 3 of 6 months. Median follow-up time was 6.1 years.

RESULTS

DGF occurred in 137 of 375 patients (37%), and DSA were present in 85 of 375 patients (23%). The incidence of DGF was similar in DSA-positive (DSApos)-patients and DSA-negative (DSAneg)-patients (40% versus 36%; P = 0.45). In DSAneg-patients, 5-year graft survival was not different with/without DGF (81% versus 83%; P = 0.48). By contrast, in DSApos-patients, 5-year graft survival was significantly lower with DGF (64% versus 79%; P = 0.01). Moreover, DSApos-patients with DGF had a higher 1-year incidence of subclinical rejection, which were mostly antibody-mediated or mixed rejection phenotypes. Graft loss due to rejection was significantly more frequent in DSApos-patients with DGF (5/34; 15%) compared to DSApos-patients without DGF (2/51; 4%), and DSAneg-patients with/without DGF (3/103; 3% and 4/187; 2%, respectively) (P = 0.005). In a multivariate Cox model, DSA with DGF was an independent predictor for graft (hazard ratio = 2.84 [95% confidence interval, 1.54-5.06]; P = 0.001) and death-censored graft loss (hazard ratio = 4.65 [95% confidence interval, 1.83-11.51]; P = 0.002).

CONCLUSIONS

DGF has a much more detrimental impact in DSApos-patients than in DSAneg-patients, which is likely related to a higher incidence of antibody-mediated rejection. If possible, the combined risks of DGF and DSA should be avoided.

Donor Age, Cold Ischemia Time, and Delayed Graft Function

BACKGROUND AND OBJECTIVES

Increased donor age is one of the most important risk factors for delayed graft function (DGF), and previous studies suggest that the harmful effect of cold ischemia time is increased in kidneys from older donors. Our aim was to study the association of increased donor age and cold ischemia time with the risk of delayed graft function in a large cohort kidney transplants from the current era.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The Scientific Registry of Transplant Recipients was used for this observational, retrospective registry analysis to identify all deceased donor kidney transplantations in the United States between 2010 and September 2018, who were on dialysis pretransplantation (n=90,810). The association of donor age and cold ischemia time with the risk of DGF was analyzed in multivariable models adjusted for recipient characteristics (age, race, sex, diabetes, calculated panel-reactive antibodies, pretransplant dialysis duration) and donor characteristics (cause of death, sex, race, body mass index, creatinine, donation after circulatory death status, history of hypertension, and HLA mismatch).

RESULTS

Cold ischemia time and donor age were independently associated with the risk of DGF, but the risk of DGF was not statistically significantly lower in donor age categories between 50 and 64 years, compared with donors ≥65 years. The harmful association of cold ischemia time was not higher in kidneys from older donors in any age category, not even among donation after circulatory death donors. When donor risk was assessed with kidney donor profile index, although a statistically significant interaction with cold ischemia time was found, no practically meaningful increase in cold-ischemia susceptibility of kidneys with a high kidney donor profile index was found.

CONCLUSIONS

We were unable to demonstrate an association between donor age and DGF. The association of longer cold ischemia time with the risk of DGF was not magnified in older or more marginal donors.

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

There are conflicting data about the role of transplant nephrectomy and immunosuppression withdrawal on the development of allosensitization and the impact on re-transplantation. We divided 109 first graft recipients into two groups according to whether they underwent nephrectomy (NX+, n = 61) or their graft was left in situ (NX-, n = 48). Sera were assessed for HLA-A/B/Cw/DR/DQ antibodies at the time of NX/transplant failure and after 3, 6, 12, 24 months. The NX+ group showed a higher rate of donor specific antibody (DSA) and non-DSA human leukocyte antigen (HLA) antibody production at all the time points. Multivariable analysis showed that nephrectomy was a strong, independent risk factor for the development of DSAs after 12 and 24 months (P = 0.005 and 0.008). In the NX- group, low tacrolimus levels correlated with DSA formation (AUC 0.817, P = 0.002; best cut-off level 2.9 ng/ml). Analysis with a standardized pool of UK donors showed a more difficult grade of HLA matchability following nephrectomy compared with the NX- group. Nephrectomy is followed by the long-term production of DSA and non-DSA HLA antibodies and negatively impacts on the chances of finding a HLA-compatible kidney. Tacrolimus levels ≥3 ng/ml are protective against the development of allosensitization and could facilitate re-transplantation in the NX- group.

The national landscape of deceased donor kidney transplantation for the highly sensitized: Transplant rates, waitlist mortality, and posttransplant survival under KAS

Deceased donor kidney transplantation (DDKT) rates for highly sensitized (HS) candidates increased early after implementation of the Kidney Allocation System (KAS) in 2014. However, this may represent a bolus effect, and a granular investigation of the current state of DDKT for HS candidates remains lacking. We studied 270 722 DDKT candidates from the SRTR from 12/4/2011 to 12/3/2014 ("pre-KAS") and 12/4/2014 to 12/3/2017 ("post-KAS"), analyzing DDKT rates for HS candidates using adjusted negative binomial regression. Post-KAS, candidates with the highest levels of sensitization had an increased DDKT rate compared with pre-KAS (cPRA 98% adjusted incidence rate ratio [aIRR]:1.27 1.772.46 P = .001, cPRA 99% aIRR:3.18 4.365.98 P < .001, cPRA 99.5-99.9% aIRR:16.91 24.2934.89 P < .001, and cPRA 99.9%+ aIRR:8.79 11.5815.26 P < .001). To determine whether these changes produced more equitable access to DDKT, we compared DDKT rates of HS to non-HS candidates (cPRA 0-79%). Post-KAS, cPRA, 98% candidates had an equivalent DDKT rate (aIRR:0.65 0.941.36 , P = .8) to non-HS candidates, whereas 99% candidates had a higher DDKT rate (aIRR:1.19 1.682.38 , P = .02). Although cPRA 99.5-99.9% candidates had an increased DDKT rate (aIRR:2.46 3.504.98 , P < .001) compared to non-HS candidates, cPRA 99.9%+ candidates had a significantly lower DDKT rate (aIRR:0.29 0.400.56 , P < .001). KAS has improved access to DDKT for HS candidates, although substantial imbalance exists between cPRA 99.5-99.9% and 99.9%+ candidates.

Meeting report of the STAR-Sensitization in Transplantation Assessment of Risk: Naïve Abdominal Transplant Organ subgroup focus on kidney transplantation

The development of de novo donor-specific HLA antibody (dnDSA) is a critical feature contributing to late allograft failure. The complexity of the issue is further complicated by organ-specific differences, detection techniques, reliance of tissue histopathology and changing diagnostic criteria, ineffective therapies, and lack of consensus. To tackle these issues, the Sensitization in Transplantation Assessment of Risk (STAR) 2017 was initiated as a collaboration of the American Society of Transplantation and American Society of Histocompatibility and Immunogenetics consisting of 8 working groups with the goal to provide guidelines on how to assess risk and risk stratify patients based on their potential alloimmune and DSA status. Herein is a summary of discussions by the Naïve Abdominal Working Group, highlighting currently available data and identifying gaps in our knowledge on the development and impact of dnDSA following kidney transplantation.

Does Rabbit Antithymocyte Globulin (Thymoglobuline®) Have a Role in Avoiding Delayed Graft Function in the Modern Era of Kidney Transplantation?

Delayed graft function (DGF) increases the risk of graft loss by up to 40%, and recent developments in kidney donation have increased the risk of its occurrence. Lowering the risk of DGF, however, is challenging due to a complicated etiology in which ischemia-reperfusion injury (IRI) leads to acute tubular necrosis. Among various strategies explored, the choice of induction therapy is one consideration. Rabbit antithymocyte globulin (rATG [Thymoglobuline]) has complex immunomodulatory effects that are relevant to DGF. In addition to a rapid and profound T-cell depletion, rATG inhibits leukocyte migration and adhesion. Experimental studies of rATG have demonstrated attenuated IRI-related tissue damage in reperfused tissues, consistent with histological evidence from transplant recipients. Starting rATG intraoperatively instead of postoperatively can improve kidney graft function and reduce the incidence of DGF. rATG is effective in preventing acute rejection in kidney transplant recipients at high immunological risk, supporting delayed calcineurin inhibitor (CNI) introduction which protects the graft from early insults. A reduced rate of DGF has been reported with rATG (started intraoperatively) and delayed CNI therapy compared to IL-2RA induction with immediate CNI in patients at high immunological risk, but not in lower-risk patients. Overall, induction with rATG induction is the preferred choice for supporting delayed introduction of CNI therapy to avoid DGF in high-risk patients but shows no benefit versus IL-2RA in lower-risk individuals. Evidence is growing that intraoperative rATG ameliorates IRI, and it seems reasonable to routinely start rATG before reperfusion.

Delayed graft function is associated with an increased rate of renal allograft rejection: A retrospective single center analysis

INTRODUCTION

The association of delayed graft function (DGF) and biopsy proven acute rejection (BPAR) of renal allografts is controversial. Borderline rejections comprise a major portion of biopsy results but the significance of such histologic changes is debated. The present study explores the impact of DGF on BPAR with a special emphasis on discriminating the effects of borderline rejection.

METHODS

Single center analysis of 417 deceased donor kidney recipients (age>18; transplantation date 1/2008-2/2015). Patients with primary non-function were excluded. DGF was defined as the need for dialysis within the first week after transplantation. Acute rejection was defined according to Banff criteria. Cox proportional hazards models were used to examine the relationship of DGF with BPAR within the first year.

RESULTS

No graft loss was observed during the first year after transplantation. DGF significantly associated with BPAR in the first year, irrespective of whether borderline rejections were included (HR 1.71, 95%CI 1.16,2.53) or excluded (HR 1.79, 95%CI 1.13,2.84).

CONCLUSION

DGF is significantly associated with rejection-with or without borderline changes-within the first year.

Early failure of kidney transplants in the current era-a national cohort study

Although short-term outcome after kidney transplantation has improved, a small proportion of grafts are lost during the first year. We characterize in detail all early graft losses in the current era in a nationwide cohort of kidney transplant recipients. Altogether 2447 kidney transplantations, performed between June 2004 and October 2016, were included. All graft losses (return to dialysis or patient death) occurring during the first post-transplant year were characterized. During the first post-tranplant year, altogether 109 grafts were lost, 67 grafts failed, and 42 patients died. Fifty-five per cent of the deaths were due to cardiovascular causes, and 29% due to infectious causes. Twenty-one per cent of the failed grafts were primary nonfunction of unknown reason, 34% were lost due to venous thrombosis and 9% due to arterial thrombosis, but only 10 (15%) patients lost a graft due to acute cellular or humoral rejection. Independent risk factors for death included diabetes, and longer duration of pretransplant dialysis treatment, whereas risk factors for graft failure included increased level of panel-reactive antibodies and increased cold ischaemia time. Kidney allografts are rarely lost due to immunological reasons during the first post-transplant year. The most common causes of early death after transplantation are cardiovascular and infectious causes.

Evaluation of predictive models for delayed graft function of deceased kidney transplantation

Background

This study aimed to evaluate the predictive power of five available delayed graft function (DGF)-prediction models for kidney transplants in the Chinese population.

Results

Among the five models, the Irish 2010 model scored the best in performance for the Chinese population. Irish 2010 model had an area under the receiver operating characteristic (ROC) curve of 0.737. Hosmer-Lemeshow goodness-of-fit test showed that the Irish 2010 model had a strong correlation between the calculated DGF risk and the observed DGF incidence (p = 0.887). When Irish 2010 model was used in the clinic, the optimal upper cut-off was set to 0.5 with the best positive likelihood ratio, while the lower cut-off was set to 0.1 with the best negative likelihood ratio. In the subgroup of donor aged ≤ 5, the observed DGF incidence was significantly higher than the calculated DGF risk by Irish 2010 model (27% vs. 9%).

Materials and Methods

A total of 711 renal transplant cases using deceased donors from China Donation after Citizen's Death Program at our center between February 2007 and August 2016 were included in the analysis using the five predictive models (Irish 2010, Irish 2003, Chaphal 2014, Zaza 2015, Jeldres 2009).

Conclusions

Irish 2010 model has the best predictive power for DGF risk in Chinese population among the five models. However, it may not be suitable for allograft recipients whose donor aged ≤ 5-year-old.

Donor-specific HLA antibodies in predicting crossmatch outcome: Comparison of three different laboratory techniques

The virtual crossmatch, which is based on single antigen bead technology, is used in the prediction of crossmatch results. However, this assay differs in sensitivity and specificity from crossmatch methods. In our study, the results of physical crossmatches, performed with three different methods, were assessed against virtual crossmatch results. The aim was to determine the potential cut-off values for donor specific antibodies (DSA) that would predict the crossmatch results obtained by different methods. The results of different crossmatch techniques were correlated with the virtual crossmatch. The receiver operating characteristic (ROC) analysis revealed the Flow cytometric crossmatch (FCXM) and Luminex crossmatch (LXM) to be the most accurate, with area under curve (AUC) values of 0.861 and 0.805, respectively. While we found that the virtual crossmatch correlated well with all the crossmatch results, FCXM produced the best results (83% of the DSA detected). LXM outperformed the other tests in terms of the accuracy in separating class II DSA.

Delayed graft function and its management in children

Delayed graft function (DGF) is commonly defined as the requirement for dialysis within the first 7 days following renal transplantation. The major underlying mechanism is related to ischaemia/reperfusion injury, which includes microvascular inflammation and cell death and apoptosis, and to the regeneration processes. Several clinical factors related to donor, recipient and organ procurement/transplantation procedures may increase the risk of DGF, including donor cardiovascular instability, older donor age, donor creatinine concentration, long cold ischaemia time and marked body mass index of both the donor and recipient. Some of these parameters have been used in specific predictive formulas created to assess the risk of DGF. A variety of other pre-, intra- and post-transplant clinical factors may also increase the risk of DGF, such as potential drug nephrotoxicity, surgical problems and/or hyperimmunization of the recipient. DGF may decrease the long-term graft function, but data on this effect are inconsistent, partially due to the many different types of organ donation. Relevant management strategies may be classified into the classic clinical approach, which has the aim of minimizing the individual risk factors of DGF, and specific pharmacologic strategies, which are designed to prevent or treat ischaemia/reperfusion injury. Both strategies are currently being evaluated in clinical trials.

C1q-binding anti-HLA antibody assay: A test dilemma

Detection of donor-specific anti-HLA antibodies in patients with kidney graft, or awaiting kidney graft, acts as a predictor for antibody mediated rejection. Several methods are in practice for the detection of anti-HLA antibodies; including the latest introduction of C1q-binding anti-HLA antibody method. This method depends on detecting complement fixing anti-HLA antibodies on single antigen beads using C1q as the marker for the presence of those antibodies. Here we discuss recent data on this method and present a working hypothesis for explaining the inability of this method to detect low titer anti-HLA antibodies.