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CD4+T-helper cells play an important role in alloimmune reactions following transplantation by stimulating humoral as well as cellular responses, which might lead to failure of the allograft. CD4+memory T-helper cells from a previous immunizing event can potentially be reactivated by exposure to HLA mismatches that share T-cell epitopes with the initial immunizing HLA. Consequently, reactivity of CD4+memory T-helper cells toward T-cell epitopes that are shared between immunizing HLA and donor HLA could increase the risk of alloimmunity following transplantation, thus affecting transplant outcome. In this study, the amount of T-cell epitopes shared between immunizing and donor HLA was used as a surrogate marker to evaluate the effect of donor-reactive CD4+memory T-helper cells on the 10-year risk of death-censored kidney graft failure in 190 donor/recipient combinations using the PIRCHE-II algorithm. The T-cell epitopes of the initial theoretical immunizing HLA and the donor HLA were estimated and the number of shared PIRCHE-II epitopes was calculated. We show that the natural logarithm-transformed PIRCHE-II overlap score, or Shared T-cell EPitopes (STEP) score, significantly associates with the 10-year risk of death-censored kidney graft failure, suggesting that the presence of pre-transplant donor-reactive CD4+memory T-helper cells might be a strong indicator for the risk of graft failure following kidney transplantation.

Item does not contain fulltext BACKGROUND: Pre-transplant donor-specific anti-human leucocyte antigen (HLA) antibodies (DSAs) are associated with impaired kidney graft survival while the clinical relevance of non-donor-specific anti-HLA antibodies (nDSAs) is more controversial. The aim of the present paired kidney graft study was to compare the clinical relevance of DSAs and nDSAs. METHODS: To eliminate donor and era-dependent factors, a post hoc paired kidney graft analysis was performed as part of a Dutch multicentre study evaluating all transplantations between 1995 and 2005 with available pre-transplant serum samples. Anti-HLA antibodies were detected with a Luminex single-antigen bead assay. RESULTS: Among 3237 deceased donor transplantations, we identified 115 recipient pairs receiving a kidney from the same donor with one recipient being DSA positive and the other without anti-HLA antibodies. Patients with pre-transplant DSAs had a significantly lower 10-year death-censored graft survival (55% versus 82%, P=0.0001). We identified 192 pairs with one recipient as nDSA positive (against Class I and/or II) and the other without anti-HLA antibodies. For the patients with nDSAs against either Class I or II, graft survival did not significantly differ compared with patients without anti-HLA antibodies (74% versus 77%, P = 0.79). Only in patients with both nDSAs Class I and II was there a trend towards a lower graft survival (58%, P = 0.06). Lastly, in a small group of 42 recipient pairs, 10-year graft survival in recipients with DSAs was 49% compared with 68% in recipients with nDSAs (P=0.11). CONCLUSION: This paired kidney analysis confirms that the presence of pre-transplant DSAs in deceased donor transplantations is a risk marker for graft loss, whereas nDSAs in general are not associated with a lower graft survival. Subgroup analysis indicated that only in broadly sensitized patients with nDSAs against Class I and II, nDSAs may be a risk marker for graft loss in the long term.

Background Complement-fixing antibodies against donor HLA are considered a contraindication for kidney transplant. A modification of the IgG single-antigen bead (SAB) assay allows detection of anti-HLA antibodies that bind C3d. Because early humoral graft rejection is considered to be complement mediated, this SAB-based technique may provide a valuable tool in the pretransplant risk stratification of kidney transplant recipients.Methods Previously, we established that pretransplant donor-specific anti-HLA antibodies (DSAs) are associated with increased risk for long-term graft failure in complement-dependent cytotoxicity crossmatch-negative transplants. In this study, we further characterized the DSA-positive serum samples using the C3d SAB assay.Results Among 567 pretransplant DSA-positive serum samples, 97 (17%) contained at least one C3d-fixing DSA, whereas 470 (83%) had non-C3d-fixing DSA. At 10 years after transplant, patients with C3d-fixing antibodies had a death-censored, covariate-adjusted graft survival of 60%, whereas patients with non-C3d-fixing DSA had a graft survival of 64% (hazard ratio, 1.02; 95% confidence interval, 0.70 to 1.48 for C3d-fixing DSA compared with non-C3d-fixing DSA; P=0.93). Patients without DSA had a 10-year graft survival of 78%.Conclusions The C3d-fixing ability of pretransplant DSA is not associated with increased risk for graft failure.

The clinical significance of non‐HLA antibodies on renal allograft survival is a matter of debate, due to differences in reported results and lack of large‐scale studies incorporating analysis of multiple non‐HLA antibodies simultaneously. We developed a multiplex non‐HLA antibody assay against 14 proteins highly expressed in the kidney. In this study, the presence of pretransplant non‐HLA antibodies was correlated to renal allograft survival in a nationwide cohort of 4770 recipients transplanted between 1995 and 2006. Autoantibodies against Rho GDP‐dissociation inhibitor 2 (ARHGDIB) were significantly associated with graft loss in recipients transplanted with a deceased‐donor kidney (N = 3276) but not in recipients of a living‐donor kidney (N = 1496). At 10 years after deceased‐donor transplantation, recipients with anti‐ARHGDIB antibodies (94/3276 = 2.9%) had a 13% lower death‐censored covariate‐adjusted graft survival compared to the anti‐ARHGDIB‐negative (3182/3276 = 97.1%) population (hazard ratio 1.82; 95% confidence interval, 1.32‐2.53; P = .0003). These antibodies occur independently from donor‐specific anti‐HLA antibodies (DSA) or other non‐HLA antibodies investigated. No significant relations with graft loss were found for the other 13 non‐HLA antibodies. We suggest that pretransplant risk assessment can be improved by measuring anti‐ARHGDIB antibodies in all patients awaiting deceased‐donor transplantation., From a multicenter evaluation of kidney transplants, the authors report that the pretransplant presence of autoantibodies against ARHGDIB are associated with long‐term graft loss in recipients transplanted with a deceased donor kidney, independent from donor‐specific HLA antibodies.

Whereas regular allocation avoids unacceptable mismatches on the donor organ, allocation to highly sensitized patients within the Eurotransplant Acceptable Mismatch (AM) program is based on the patient's HLA phenotype plus acceptable antigens. These are HLA antigens to which the patient never made antibodies, as determined by extensive laboratory testing. AM patients have superior long‐term graft survival compared with highly sensitized patients in regular allocation. Here, we questioned whether the AM program also results in lower rejection rates. From the PROCARE cohort, consisting of all Dutch kidney transplants in 1995‐2005, we selected deceased donor single transplants with a minimum of 1 HLA mismatch and determined the cumulative 6‐month rejection incidence for patients in AM or regular allocation. Additionally, we determined the effect of minimal matching criteria of 1 HLA‐B plus 1 HLA‐DR, or 2 HLA‐DR antigens on rejection incidence. AM patients showed significantly lower rejection rates than highly immunized patients in regular allocation, comparable to nonsensitized patients, independent of other risk factors for rejection. In contrast to highly sensitized patients in regular allocation, minimal matching criteria did not affect rejection rates in AM patients. Allocation based on acceptable antigens leads to relatively low‐risk transplants for highly sensitized patients with rejection rates similar to those of nonimmunized individuals., The authors show that kidney allocation to highly sensitized patients based on proven acceptable HLA antigens results in a significantly lower incidence of rejection episodes when compared to allocation based on the avoidance of unacceptable HLA antigens only.

Supplemental Digital Content is available in the text., Background. There is no consensus in the literature on the interpretation of single-antigen bead positive for a specific HLA antibody. Methods. To inform the debate, we studied the relationship between various single-antigen bead positivity algorithms and the impact of resulting donor-specific HLA antibody (DSA) positivity on long-term kidney graft survival in 3237 deceased-donor transplants. Results. First, we showed that the interassay variability can be greatly reduced when working with signal-to-background ratios instead of absolute median fluorescence intensities (MFIs). Next, we determined pretransplant DSA using various MFI cutoffs, signal-to-background ratios, and combinations thereof. The impact of the various cutoffs was studied by comparing the graft survival between the DSA-positive and DSA-negative groups. We did not observe a strong impact of various cutoff levels on 10-year graft survival. A stronger relationship between the cutoff level and 1-year graft survival for DSA-positive transplants was found when using signal-to-background ratios, most pronounced for the bead of the same HLA locus with lowest MFI taken as background. Conclusions. With respect to pretransplant risk stratification, we propose a signal-to-background ratio-6 (using the bead of the same HLA-locus with lowest MFI as background) cutoff of 15 combined with an MFI cutoff of 500, resulting in 8% and 21% lower 1- and 10-year graft survivals, respectively, for 8% DSA-positive transplants.

Background Few studies have evaluated the effect of different immunosuppressive strategies on long-term kidney transplant outcomes. Moreover, as they were usually based on historical data, it was not possible to account for the presence of pretransplant donor-specific human-leukocyte antigen antibodies (DSA), a currently recognized risk marker for impaired graft survival. The aim of this study was to evaluate to what extent frequently used initial immunosuppressive therapies increase graft survival in immunological low-risk patients. Methods We performed an analysis on the PROCARE cohort, a Dutch multicentre study including all transplantations performed in the Netherlands between 1995 and 2005 with available pretransplant serum (n = 4724). All sera were assessed for the presence of DSA by a luminex single-antigen bead assay. Patients with a previous kidney transplantation, pretransplant DSA or receiving induction therapy were excluded from the analysis. Results Three regimes were used in over 200 patients: cyclosporine (CsA)/prednisolone (Pred) (n = 542), CsA/mycophenolate mofetil (MMF)/Pred (n = 857) and tacrolimus (TAC)/MMF/Pred (n = 811). Covariate-adjusted analysis revealed no significant differences in 10-year death-censored graft survival between patients on TAC/MMF/Pred therapy (79%) compared with patients on CsA/MMF/Pred (82%, P = 0.88) or CsA/Pred (79%, P = 0.21). However, 1-year rejection-free survival censored for death and failure unrelated to rejection was significantly higher for TAC/MMF/Pred (81%) when compared with CsA/MMF/Pred (67%, P Conclusion These results suggest that in immunological low-risk patients excellent long-term kidney graft survival can be achieved irrespective of the type of initial immunosuppressive therapy (CsA or TAC; with or without MMF), despite differences in 1-year rejection-free survival.

The presence of donor‐specific anti‐HLA antibodies (DSAs) is associated with increased risk of graft failure after kidney transplant. We hypothesized that DSAs against HLA class I, class II, or both classes indicate a different risk for graft loss between deceased and living donor transplant. In this study, we investigated the impact of pretransplant DSAs, by using single antigen bead assays, on long‐term graft survival in 3237 deceased and 1487 living donor kidney transplants with a negative complement‐dependent crossmatch. In living donor transplants, we found a limited effect on graft survival of DSAs against class I or II antigens after transplant. Class I and II DSAs combined resulted in decreased 10‐year graft survival (84% to 75%). In contrast, after deceased donor transplant, patients with class I or class II DSAs had a 10‐year graft survival of 59% and 60%, respectively, both significantly lower than the survival for patients without DSAs (76%). The combination of class I and II DSAs resulted in a 10‐year survival of 54% in deceased donor transplants. In conclusion, class I and II DSAs are a clear risk factor for graft loss in deceased donor transplants, while in living donor transplants, class I and II DSAs seem to be associated with an increased risk for graft failure, but this could not be assessed due to their low prevalence., Via a retrospective multicenter study, the authors investigate the impact of pretransplant donor‐specific HLA antibodies on long‐term graft survival in deceased and living donor kidney transplantations.

Individual HLA mismatches may differentially impact graft survival after kidney trans plantation. Therefore, there is a need for a reliable tool to define permissible HLA mismatches in kidney transplantation. We previously demonstrated that donor-derived Predicted Indirectly ReCognizable HLA Epitopes presented by recipient HLA class II (PIRCHE-II) play a role in de novo donor-specific HLA antibodies formation after kidney transplantation. In the present Dutch multi-center study, we evaluated the possible association between PIRCHE-II and kidney graft failure in 2,918 donor-recipient couples that were transplanted between 1995 and 2005. For these donors-recipients couples, PIRCHE-II numbers were related to graft survival in univariate and multivariable analyses. Adjusted for confounders, the natural logarithm of PIRCHE-II was associated with a higher risk for graft failure [hazard ratio (HR): 1.13, 95% CI: 1.04-1.23, p = 0.003]. When analyzing a subgroup of patients who had their first transplantation, the HR of graft failure for In(PIRCHE-II) was higher compared with the overall cohort (HR: 1.22, 95% CI: 1.10-1.34, p

The best treatment for patients with end-stage renal disease is kidney transplantation. Although graft survival rates have improved in the last decades, patients still may lose their grafts partly due to the detrimental effects of donor-specific antibodies (DSA) against human leukocyte antigens (HLA) and to a lesser extent also by antibodies directed against non-HLA antigens expressed on the donor endothelium. Assays to detect anti-HLA antibodies are already in use for many years and have been proven useful for transplant risk stratification. Currently, there is a need for assays to additionally detect multiple non-HLA antibodies simultaneously in order to study their clinical relevance in solid organ transplantation. This study describes the development, technical details and validation of a high-throughput multiplex assay for the detection of antibodies against 14 non-HLA antigens coupled directly to MagPlex microspheres or indirectly via a HaloTag. The non-HLA antigens have been selected based on a literature search in patients with kidney disease or following transplantation. Due to the flexibility of the assay, this approach can be used to include alternative antigens and can also be used for screening of other organ transplant recipients, such as heart and lung.

Kidney transplantation is the best treatment option for patients with end-stage renal failure. At present, approximately 800 Dutch patients are registered on the active waiting list of Eurotransplant The waiting time in the Netherlands for a kidney from a deceased donor is on average between 3 and 4 years. During this period, patients are fully dependent on dialysis, which replaces only partly the renal function, whereas the quality of life is limited. Mortality among patients on the waiting list is high. In order to increase the number of kidney donors, several initiatives have been undertaken by the Dutch Kidney Foundation including national calls for donor registration and providing information on organ donation and kidney transplantation. The aim of the national PROCARE consortium is to develop improved matching algorithms that will lead to a prolonged survival of transplanted donor kidneys and a reduced HLA immunization. The latter will positively affect the waiting time for a retransplantation. The present algorithm for allocation is among others based on matching for HLA antigens, which were originally defined by antibodies using serological typing techniques. However, several studies suggest that this algorithm needs adaptation and that other immune parameters which are currently not included may assist in improving graft survival rates. We will employ a multicenter-based evaluation on 5429 patients transplanted between 1995 and 2005 in the Netherlands. The association between key clinical endpoints and selected laboratory defined parameters will be examined, including Luminex-defined HLA antibody specificities, T and B cell epitopes recognized on the mismatched HLA antigens, non-HLA antibodies, and also polymorphisms in complement and Fc receptors functionally associated with effector functions of anti-graft antibodies. From these data, key parameters determining the success of kidney transplantation will be identified which will lead to the identification of additional parameters to be included in future matching algorithms aiming to extend survival of transplanted kidneys and to diminish HLA immunization. Computer simulation studies will reveal the number of patients having a direct benefit from improved matching, the effect on shortening of the waiting list, and the decrease in waiting time. (C) 2014 Published by Elsevier B.V.

Aim The GenDx NGSgo workflow for HLA typing using Next-generation sequencing (NGS) consists of four practical steps: amplification, library preparation, sequencing and data analysis. Out of these four steps the library preparation is the most labor intensive and most interspersed by incubations. To decrease hands-on time and reduce the risk of human error, NGSgo library preparation can be automated from start to finish using a liquid handler workstation. Here we describe the results of the automation of the NGSgo library preparation for Illumina on a Beckman Coulter Biomek 4000 workstation. The workflow was fully automated from amplicon pool to finalized library, making it completely hands-off to accommodate overnight runs and allow the operator to step away from the machine. Methods The Biomek setup included a thermal cycler, 96-well plate magnet, two peltiers devices for cooling 96-well plates and 1.5 ml tubes, a gripper tool, reagent reservoirs and liquid waste disposal. Pipetting was performed by two pipet tools. This setup allowed for flexible processing of 4 to 24 samples per run, with any number of loci. Per run only three boxes of pipetting tips were used for 24 samples. Panels with variable numbers of samples and replicate panels were processed with the Biomek. Subsequently, the pooled libraries were sequenced on a MiSeq system and the resulting data was analyzed with NGSengine software (GenDx). Results MiSeq run parameters were indicative of a high-quality sequencing runs. Read depth, mappability and noise levels of the sequence data presented here showed that the automated workflow resulted in high quality reads and accurate typings. Results from the replicate panel showed a 100% typing match. Conclusions – NGSgo library preparation for 4 to 24 samples can be performed on the Biomek 4000 platform, without manual intervention. – The automated workflow results in high-quality reproducible libraries. – Performing automated NGSgo library preparation as described here reduces hands-on time from 1.5 h to 10 min as compared to manual execution. B. Luiken: 5. Employee; Company/Organization; GenDx. E. Tavkin: 5. Employee; Company/Organization; Beckman Coulter. S. Parakh: 5. Employee; Company/Organization; Beckman Coulter. J. Lu: 5. Employee; Company/Organization; Beckman Coulter. A. Jackson: 5. Employee; Company/Organization; Beckman Coulter. S. van Wageningen: 5. Employee; Company/Organization; GenDx. M. Penning: 5. Employee; Company/Organization; GenDx.

Aim Individual HLA mismatches may have differential effects on graft survival after kidney transplantation. Therefore, there is a need for a reliable tool to define permissible HLA mismatches in kidney transplantation. We previously demonstrated that donor-derived Predicted Indirectly ReCognizable HLA epitopes presented by recipient HLA class-II (PIRCHE-II) play a role in de novo donor-specific HLA antibody formation after kidney transplantation. Moreover, we also showed that PIRCHE-II is involved in HLA antibody formation after pregnancy. In the present Dutch multi-center study we evaluated the possible association between PIRCHE-II and kidney graft failure in 2918 donor-recipient couples that were transplanted between 1995 and 2005. Methods For all donors-recipients couples, PIRCHE-II numbers were determined and related to graft survival in both univariate and multivariable analyses. Results Adjusted for confounders, the natural logarithm of PIRCHE-II was associated with a higher risk for graft failure (HR:1.13, 95% CI:1.04–1.23, p = 0.003). Univariately analyzed, patients with low PIRCHE-II numbers had a better 10-years graft survival than patients with higher PIRCHE-II numbers (p = 0.006; PIRCHE-II strata: Conclusions Our data suggest that the PIRCHE-II algorithm is a valuable tool to discriminate between permissible HLA mismatches and high-risk HLA mismatches in kidney transplantation. Inclusion of PIRCHE-II in donor-selection criteria may eventually lead to an improved kidney graft survival.

The new A*03:134 differs from A*03:01:01:01 by one amino acid change at codon 264.