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The effectiveness of T cell-mediated rejection (TCMR) therapy for achieving histological remission remains undefined in patients on modern immunosuppression. We systematically identified, critically appraised and summarized the incidence and histological outcomes after TCMR treatment in patients on tacrolimus (Tac) and mycophenolic acid (MPA). English-language publications were searched in MEDLINE (Ovid), Embase (Ovid), Cochrane Central (Ovid), CINAHL (EBSCO), Clinicaltrials.gov (NLM) up to January 2021. Study quality was assessed with National Institutes of Health Study Quality Tool. We pooled results using an inverse variance, random-effects model and report the binomial proportions with associated 95% confidence intervals (95% CI). Statistical heterogeneity was explored using the I2 statistic. From 2,875 screened citations, we included 12 studies (1,255 participants). Fifty-eight percent were good/high quality while the rest were moderate quality. Thirty-nine percent of patients (95%CI 0.26-0.53, I2 77%) had persistent ≥Banff Borderline TCMR 2-9 months after anti-rejection therapy. Pulse steroids and augmented maintenance immunosuppression were mainstays of therapy, but considerable practice heterogeneity was present. A high proportion of biopsy-proven rejection exists after treatment emphasizing the importance of histology to characterize remission. Anti-rejection therapy is foundational to transplant management but well-designed clinical trials in patients on Tac/MPA immunosuppression are lacking to define the optimal therapeutic approach.

Malaltia renal en fase terminal; Trasplantament de ronyó Enfermedad renal en etapa terminal; Transplante de riñón End-stage renal disease; Kidney Transplant Background. There are challenges in designing adequate, well-controlled studies of patients with active antibody-mediated rejection (AMR) after kidney transplantation (KTx). Methods. We assessed the functional relationship between change in estimated glomerular filtration rate (eGFR) following the diagnosis of AMR and the risk of subsequent death-censored graft failure using the joint modeling framework. We included recipients of solitary KTx between 1995 and 2013 at 4 transplant centers diagnosed with biopsy-proven active AMR at least 1 year post-KTx, who had a minimum of 3-year follow-up. Results. A total of 91 patients across participating centers were included in the analysis. Of the 91 patients, n = 54 patients (59%) met the death-censored graft failure endpoint and n = 62 patients (68%) met the all-cause graft failure composite endpoint. Kaplan-Meier death-censored graft survival rates at 12, 36, and 60 months postdiagnosis of AMR pooled across centers were 88.9%, 58.9%, and 36.4%, respectively. Spaghetti plots indicated a linear trend in the change in eGFR, especially in the first 12 months postdiagnosis of active AMR. A significant change in eGFR was observed within the first 12 months postdiagnosis of active AMR, getting worse by a factor of −0.757 mL/min/1.73 m2 per month during the 12-month analysis period (a delta of −9.084 mL/min/1.73 m2 at 1 y). Notably, an extrapolated 30% improvement in the slope of eGFR in the first 12 months was associated with a 10% improvement in death-censored graft failure at 5 years. Conclusions. If prospectively validated, this study may inform the design of pivotal clinical trials for therapies for late AMR.

Clinicians have few tools to predict the risk of alloimmune injury that would guide immunosuppression management in renal transplant patients. We evaluated human leukocyte antigen (HLA)-DR/DQ molecular mismatch to predict de novo donor-specific antibodies (DSAs) during the first year of transplant and explored how differences in tacrolimus exposure may modulate this risk. HLA-DR and -DQ eplet mismatches were determined between 444 donor-recipient pairs in Denver, Colorado between 2007 and 2013. Previously defined mismatch thresholds stratified recipients into low- (N = 119), intermediate- (N = 153), and high- (N = 172) risk categories. The area under the curve for DSA at 1 year was 0.84 and 0.82 for HLA-DR and HLA-DQ eplet mismatches, respectively. Compared to low-risk patients, there was a graded increase in risk of DR/DQ DSA in intermediate (HR 15.39, 95% CI 2.01-118.09, p = .009) and high-risk (HR 23.81, 95% CI 3.17-178.66, p = 0.002) categories. Intermediate- and high-risk patients with a mean tacrolimus6 ng/ml versus8 ng/ml had increased risk of DR/DQ DSA at 1 year (HR 2.34, 95% CI 1.05-5.22, p = .04). HLA molecular mismatch represents a reproducible, objective, and clinically relevant tool to stratify patients by alloimmune risk and may help guide personalized immunosuppression management.

Improving long‐term kidney transplant outcomes requires novel treatment strategies, including delayed calcineurin inhibitor (CNI) substitution, tested using informative trial designs. An alternative approach to the usual superiority‐based trial is a noninferiority trial design that tests whether an investigational agent is not unacceptably worse than standard of care. An informative noninferiority design, with biopsy‐proven acute rejection (BPAR) as the endpoint, requires determination of a prespecified, evidence‐based noninferiority margin for BPAR. No such information is available for delayed CNI substitution in kidney transplantation. Herein we analyzed data from recent kidney transplant trials of CNI withdrawal and “real world” CNI‐ based standard of care, containing subjects with well‐documented evidence of immune quiescence at 6 months posttransplant—ideal candidates for delayed CNI substitution. Our analysis indicates an evidence‐based noninferiority margin of 13.8% for the United States Food and Drug Administration's composite definition of BPAR between 6 and 24 months posttransplant. Sample size estimation determined that ~225 randomized subjects would be required to evaluate noninferiority for this primary clinical efficacy endpoint, and superiority for a renal function safety endpoint. Our findings provide the basis for future delayed CNI substitution noninferiority trials, thereby increasing the likelihood they will provide clinically implementable results and achieve regulatory approval., This meta‐analysis defines a noninferiority margin to use in the design of a phase II/III delayed calcineurin inhibitor substitution trial in kidney transplantation.

Purpose of review A precise understanding of the alloimmune risk faced by individual recipients at the time of transplant is an unmet need in transplantation. Although conventional HLA donor-recipient mismatch is too imprecise to fulfil this need, HLA molecular mismatch increases the precision in alloimmune risk assessment by quantifying the difference between donors and recipients at the molecular level. Recent findings Within each conventional HLA mismatch the number, type, and position of mismatched amino acids create a wide range of HLA molecular mismatches between recipients and donors. Multiple different solid organ transplant groups from across the world have correlated HLA molecular mismatch with transplant outcomes including de novo donor-specific antibody development, antibody-mediated rejection, T-cell-mediated rejection, and allograft survival. Summary All alloimmunity is driven by differences between donors and recipients at the molecular level. HLA molecular mismatch may represent an advancement compared to traditional HLA antigen mismatch as a fast, reproducible, cost-effective way to improve alloimmune risk assessment at the time of transplantation to move the field towards precision medicine.

Prognostic biomarkers of T cell–mediated rejection (TCMR) have not been adequately studied in the modern era. We evaluated 803 renal transplant recipients and correlated HLA‐DR/DQ molecular mismatch alloimmune risk categories (low, intermediate, high) with the severity, frequency, and persistence of TCMR. Allograft survival was reduced in recipients with Banff Borderline (hazard ratio [HR] 2.4, P = .003) and Banff ≥ IA TCMR (HR 4.3, P, Alloimmune risk categorization using HLA‐DR/DQ molecular mismatch risk correlates with the severity, frequency, and persistence of T cell–mediated rejection and with graft survival, independent of de novo DSA.

Improving precision in predicting alloreactivity is an important unmet need and may require individualized consideration of non-HLA antibodies. We report a 21-year-old man with kidney failure from immunoglobulin A nephropathy who met all traditional criteria for a "low-risk" transplant for immune memory. He was unsensitized and received a haplotype-matched living donor kidney transplant from his mother. There were no anti-HLA donor-specific antibodies and flow cross-match was negative. After immediate function, he developed delayed graft function on postoperative day 2. The transplant biopsy specimen was suggestive of antibody-mediated rejection and acute tubular injury with increased vimentin proximal tubular expression compared to the implantation biopsy specimen. He had a history of juvenile idiopathic arthritis, and non-HLA antibody screening demonstrated preformed anti-vimentin antibody. He was successfully treated with plasmapheresis, intravenous immunoglobulin, antithymocyte globulin, and methylprednisolone, with renal recovery. The follow-up biopsy specimen demonstrated decreased vimentin expression with decreased alloinflammation, and graft function remains stable at 1 year posttransplantation (estimated glomerular filtration rate, 62mL/min/1.73m2). We postulate that preformed anti-vimentin autoantibodies bound to vimentin expressed on apoptotic tubular epithelial cells induced by ischemia-reperfusion injury and to constitutively expressed vimentin on peritubular capillaries and podocytes. Our case is suggestive of the involvement of anti-vimentin antibody, for which the pathogenic epitopes may be exposed during ischemia-reperfusion injury.

Introduction Pneumocystis jirovecii pneumonia (PJP) is a significant cause of morbidity and mortality in transplant patients yet little is known about their adherence to prophylaxis. The goal of this study was to evaluate patient uptake and long-term adherence after implementing universal, lifelong PJP prophylaxis. Materials and methods This retrospective cohort study evaluated an adult kidney transplant program 18-months after initiating trimethoprim-sulfamethoxazole (TMP-SMX) 80/400 mg thrice-weekly following a cluster of PJP cases. The protocol incorporated multi-modal patient education and drug tolerability strategies to improve adherence, including a modified re-challenge strategy for TMP-SMX intolerance. Adherence was independently confirmed by the transplant pharmacist and nurse for each patient, with an a priori target ≥ 75% population on prophylaxis. Results Initial uptake was high with 237/250 (94.8%) patients starting prophylaxis. Long-term maintenance was high with 192/237 (81.0%) patients remaining on prophylaxis at 18-months. Of the remaining 45 patients who initiated prophylaxis, 36/237 (15.2%) were non-adherent and 9/237 (3.8%) discontinued prophylaxis by 18-months. Reasons for non-adherence included gastrointestinal upset, fear of drug reactions and cost; but the majority of reasons were not delineated by the patients (31/36, 86.1%). There was a statistically significant increase in serum creatinine 3.3 µmol/L (0.3-6.3 µmol/L 95% CI) and potassium 0.08 mmol/L (0.03-0.15 mmol/L 95% CI) in those prescribed TMP-SMX with only 3/237 (1.3%) patients discontinuing TMP-SMX for an increase in creatinine. Conclusion High rates of patient uptake (94.8%) and long-term adherence (81.0%) were observed after implementing universal lifelong PJP prophylaxis. This may be due in part to the in-depth patient education and drug tolerability strategies employed.

Purpose of review There is tremendous interest in understanding when, if, and how non-HLA antibodies contribute to allograft injury. Numerous non-HLA target antigens have been identified and sensitization to these targets have been associated with delayed allograft function, rejection, and allograft failure. This review focuses on the clinical utility of HLA antibody testing, highlighting the strengths and limitations of current clinical studies, and the need for defining characteristics to inform non-HLA antibody pathogenicity. Recent findings Clinical studies continue to show associations between non-HLA antibodies and rejection and reduced allograft survival across multiple transplanted organ types. The worst clinical outcomes continue to be observed among recipients testing positive for both non-HLA and donor-specific HLA antibodies. Mechanistic insights from both animal and clinical studies support a model in which tissue injury accompanied by an inflammatory environment influence non-HLA antibody formation and pathogenicity. Summary Immune triggers that lead to non-HLA antibody formation and pathogenicity are complex and poorly understood. The ability of non-HLA antibodies to mediate allograft injury may depend upon their affinity and strength (titer), target specificity, density of the target antigen, and synergy with donor-specific HLA antibodies.

The purpose of the STAR 2019 Working Group was to build on findings from the initial STAR report to further clarify the expectations, limitations, perceptions, and utility of alloimmune assays that are currently in use or in development for risk assessment in the setting of organ transplantation. The goal was to determine the precision and clinical feasibility/utility of such assays in evaluating both memory and primary alloimmune risks. The process included a critical review of biologically driven, state‐of‐the‐art, clinical diagnostics literature by experts in the field and an open public forum in a face‐to‐face meeting to promote broader engagement of the American Society of Transplantation and American Society of Histocompatibility and Immunogenetics membership. This report summarizes the literature review and the workshop discussions. Specifically, it highlights (1) available assays to evaluate the attributes of HLA antibodies and their utility both as clinical diagnostics and as research tools to evaluate the effector mechanisms driving rejection; (2) potential assays to assess the presence of alloimmune T and B cell memory; and (3) progress in the development of HLA molecular mismatch computational scores as a potential prognostic biomarker for primary alloimmunity and its application in research trial design., This meeting report from an AST‐ASHI expert workgroup provides recommendations on the utility and “clinical‐grade” qualification of assays and biomarkers to evaluate alloimmune risk.

BACKGROUND: In kidney transplantation, evaluating mismatches of HLA eplets—small patches of surface-exposed amino acids of the HLA molecule—instead of antigen mismatches might offer a better approach to assessing donor-recipient HLA incompatibility and improve risk assessment and prediction of transplant outcomes. METHODS: To evaluate the effect of number of eplet mismatches (mismatch load) on de novo formation of donor-specific HLA antibodies (DSAs) and transplant outcomes, we conducted a cohort study that included consecutive adult kidney recipients transplanted at a single center from March 2004 to February 2013. We performed retrospective high-resolution genotyping of HLA loci of 926 transplant pairs and used the HLAMatchmaker computer algorithm to count HLA eplet mismatches. RESULTS: De novo DSAs occurred in 43 (4.6%) patients. Multivariable analysis showed a significant independent association between antibody-verified eplet mismatch load and de novo DSA occurrence and graft failure, mainly explained by DQ antibody-verified eplet effects. The association with DQ antibody-verified eplet mismatches was linear, without a safe threshold at which de novo DSA did not occur. Odds for T cell– or antibody-mediated rejection increased by 5% and 12%, respectively, per antibody-verified DQ eplet mismatch. CONCLUSIONS: Eplet mismatches in HLA-DQ confer substantial risk for de novo DSA formation, graft rejection, and graft failure after kidney transplantation. Mismatches in other loci seem to have less effect. The results suggest that antibody-verified HLA-DQ eplet mismatch load could be used to guide personalized post-transplant immunosuppression. Adoption of molecular matching for DQA(1) and DQB(1) alleles could also help to minimize de novo DSA formation and potentially improve transplant outcomes.

Pretransplant and posttransplant alloimmune risk assessment needs to evolve towards a precision medicine model already used in other areas of medicine. Although this has not been possible with traditional risk factors available at the time of transplant, new methods of human leukocyte antigen (HLA) molecular mismatch have generated hope that alloimmune risk assessment may be precise enough for personalized treatment strategies.This review describes the various HLA molecular mismatch methods and some of the recent publications for each method. These include studies that have evaluated HLA molecular mismatch in the context of lung, pancreas and kidney transplant as a correlate with short and long-term outcomes. The limitations of traditional alloimmune risk assessment strategies are highlighted in the context of individualized patient care.Recent studies that have evaluated HLA molecular mismatch in the context of immunosuppression minimization are examples of how more precise measurements of alloimmune risk can lead to novel insights that may help personalize immunosuppression protocols.

Studies investigating the potential pathogenic effects of non-HLA antibodies (Ab) have identified Ab against the angiotensin II type 1 receptor (AT1R-Ab) as a risk factor for rejection and kidney graft loss. This study sought to validate the risk of AT1R-Ab for acute rejection and to explore the role of other non-HLA Abs in this capacity. Pre- and post-transplant sera from a cohort of 101 patients (n = 453 samples total) were tested for AT1R-Ab and other non-HLA Ab using a commercially available ELISA kit and the Luminex platform, respectively. Patients positive for pre-transplant AT1R-Ab were more likely to develop de novo donor-specific Ab (dnDSA) compared to patients that were negative for AT1R-Ab (28% vs 10%, p = 0.027). Pre-transplant positivity for AT1R-Ab was associated with TCMR in the first year post-transplant (p = 0.034), but did not predict graft loss independent of dnDSA (p = 0.063). AT1R-Ab positivity was significantly associated with positivity for Ab against the endothelin A type 1 receptor (ETAR-Ab) inclusive of all study time points (p = 0.0021). Given the high prevalence of AT1R-Ab pre-transplant (20%) and its association with dnDSA and early TCMR, a prospective study to determine if more intense immunosuppression and/or AT1R blockade has an impact on outcomes in these patients is warranted.

De novo donor-specific antibodies (dnDSAs) that develop after renal transplantation are independent predictors of allograft loss. However, it is unknown if dnDSA C1q status or titer at the time of first detection can independently predict allograft loss. In a consecutive cohort of 508 renal transplant recipients, 70 developed dnDSAs. Histologic and clinical outcomes were correlated with the C1q assay or dnDSA titer. C1q positivity correlated with dnDSA titer (p < 0.01) and mean fluorescence intensity (p < 0.01) and was more common in class II versus class I dnDSAs (p < 0.01). C1q status correlated with tubulitis (p = 0.02) and C4d status (p = 0.03) in biopsies at the time of dnDSA development, but not T cell-mediated rejection (TCMR) or antibody-mediated rejection (ABMR). De novo DSA titer correlated with Banff g, i, t, ptc, C4d scores, TCMR (p < 0.01) and ABMR (p < 0.01). Post-dnDSA graft loss was observed more frequently in recipients with C1q-positve dnDSA (p < 0.01) or dnDSA titer ≥ 1:1024 (p ≤ 0.01). However, after adjustment for clinical phenotype and nonadherence in multivariate models, neither C1q status nor dnDSA titer were independently associated with allograft loss, questioning the utility of these assays at the time of dnDSA development.

Purpose of review Stalled drug development and the lack of improvement in long-term graft survival reflect the unmet need for prognostic and predictive biomarkers in transplantation. Although conventional human leukocyte antigen (HLA) mismatch is too imprecise to fulfill this need, HLA molecular mismatch increases the precision in alloimmune risk assessment by quantifying the difference between donors and recipients at the molecular level. Recent findings Within each conventional HLA mismatch, recipients exhibit a wide range of HLA molecular mismatches with their donors. Quantifying HLA molecular mismatch improves the precision of alloimmune risk assessment for de novo donor-specific antibody development (dnDSA). Alloimmune risk categories developed analyzing dnDSA development were also found to correlate with T-cell-mediated rejection, antibody-mediated rejection, and all cause graft loss in adjusted and unadjusted models. Summary All alloimmunity is driven by differences between donors and recipients at the molecular level. HLA molecular mismatch may represent a fast, reproducible, cost-effective, way to improve alloimmune risk assessment at the time of transplantation to move the field towards precision medicine.

Alloimmune risk stratification in renal transplantation has lacked the necessary prognostic biomarkers to personalize recipient care or optimize clinical trials. HLA molecular mismatch improves precision compared to traditional antigen mismatch but has not been studied in detail at the individual molecule level. This study evaluated 664 renal transplant recipients and correlated HLA‐DR/DQ single molecule eplet mismatch with serologic, histologic, and clinical outcomes. Compared to traditional HLA‐DR/DQ whole antigen mismatch, HLA‐DR/DQ single molecule eplet mismatch improved the correlation with de novo donor‐specific antibody development (area under the curve 0.54 vs 0.84) and allowed recipients to be stratified into low, intermediate, and high alloimmune risk categories. These risk categories were significantly correlated with primary alloimmune events including Banff ≥1A T cell–mediated rejection (P = .0006), HLA‐DR/DQ de novo donor‐specific antibody development (P, Primary alloimmune risk precisely determined using HLA class II molecular mismatch may facilitate personalized treatment and monitoring strategies for kidney transplant recipients.

IntroductionSubclinical inflammation is an important predictor of death-censored graft loss, and its treatment has been shown to improve graft outcomes. Urine CXCL10 outperforms standard post-transplant surveillance in observational studies, by detecting subclinical rejection and early clinical rejection before graft functional decline in kidney transplant recipients.Methods and analysisThis is a phase ii/iii multicentre, international randomised controlled parallel group trial to determine if the early treatment of rejection, as detected by urine CXCL10, will improve kidney allograft outcomes. Incident adult kidney transplant patients (n~420) will be enrolled to undergo routine urine CXCL10 monitoring postkidney transplant. Patients at high risk of rejection, defined as confirmed elevated urine CXCL10 level, will be randomised 1:1 stratified by centre (n=250). The intervention arm (n=125) will undergo a study biopsy to check for subclinical rejection and biopsy-proven rejection will be treated per protocol. The control arm (n=125) will undergo routine post-transplant monitoring. The primary outcome at 12 months is a composite of death-censored graft loss, clinical biopsy-proven acute rejection, de novo donor-specific antibody, inflammation in areas of interstitial fibrosis and tubular atrophy (Banff i-IFTA, chronic active T-cell mediated rejection) and subclinical tubulitis on 12-month surveillance biopsy. The secondary outcomes include decline of graft function, microvascular inflammation at 12 months, development of IFTA at 12 months, days from transplantation to clinical biopsy-proven rejection, albuminuria, EuroQol five-dimension five-level instrument, cost-effectiveness analysis of the urine CXCL10 monitoring strategy and the urine CXCL10 kinetics in response to rejection therapy.Ethics and disseminationThe study has been approved by the University of Manitoba Health Research Ethics Board (HS20861, B2017:076) and the local research ethics boards of participating centres. Recruitment commenced in March 2018 and results are expected to be published in 2023. De-identified data may be shared with other researchers according to international guidelines (International Committee of Medical Journal Editors [ICJME]).Trial registration numberNCT03206801; Pre-results.

Women scientists are less likely to obtain Assistant Professorship and achieve promotion, and obtain less grant funding than men. Scientist/clinician-scientist training programs which provide salary awards as well as training and mentorship are a potential intervention to improve outcomes among women scientists. We hypothesized whether a programmatic approach to scientist/clinician-scientist training is associated with improved outcomes for women scientists in Canada when compared with salary awards alone. Trainees within the Kidney Research Scientist Core Education and National Training Program (KRESCENT), Canadian Child Health Clinician Scientist Program (CCHCSP), and the Canadian Institutes of Health Research (CIHR) salary award programs were evaluated.To examine whether the structured KRESCENT training program with salary support improves academic success for women scientists relative to salary awards alone.Retrospective cohort study.Canadian national research scientist and clinician-scientist training programs and salary awards.KRESCENT cohort (n = 59, 2005-2017), CCHCSP cohort (n = 58, 2002-2015), and CIHR (n = 571, 2005-2015) Salary Awardees for postdoctoral fellows (PDF) and new investigators (NI).National operating grant funding success, achieving an academic position as an Assistant Professor for PDF, or achieving promotion to Associate Professor for NI.The gender distribution of each cohort was determined using first name and NamepediA and was examined for PDF and NI, followed by a description of trainee outcomes by gender and training level.KRESCENT and CIHR PDF were balanced (12/27, 44% men and 55/116, 47% women) while CCHCSP had a higher proportion of women (13/20, 65%). KRESCENT and CCHCSP NI retained women scientists (19/32, 59% and 22/38, 58% women), whereas CIHR NI had fewer women (165/455, 36% women vs 290/455, 64% men,KRESCENT and CCHCSP training program cohort size and heterogeneity; assigning gender by first name may result in misclassification; lack of data on the respective applicant pools; and inability to examine intersectionality with gender, ethnicity, and sexual orientation.Overall trainee performance across programs is remarkable by community standards regardless of gender. KRESCENT and CCHCSP training programs demonstrated balanced success in their PDF and NI, whereas the CIHR awardees had reduced representation of women scientists from PDF to NI. This exploratory study highlights the utility of programmatic training approaches like the KRESCENT program as potential tools to support and retain women scientists in the academic pipeline during the challenging PDF to NI transition period.Les chercheuses sont moins susceptibles que les hommes d’obtenir une promotion ou un poste de professeur adjoint, en plus d’obtenir moins de subventions. Des programmes de formation pour les chercheurs et chercheurs cliniciens offrant des bourses salariales ainsi que de la formation et du mentorat pourraient s’avérer pertinents pour améliorer la situation des femmes en sciences. Nous avons émis l’hypothèse qu’une approche programmatique de la formation des chercheurs et chercheurs cliniciens pourrait améliorer les résultats pour les chercheuses canadiennes comparativement aux bourses salariales seules. Pour ce faire, les stagiaires du Programme national de formation scientifique et d’encadrement des chercheurs spécialisés dans le domaine rénal (KRESCENT), du Programme canadien des cliniciens-chercheurs en santé de l’enfant (PCCCSE) et des programmes de bourses salariales des Instituts de recherche en santé du Canada (IRSC) ont été évalués.Vérifier si le programme de formation structuré KRESCENT avec soutien salarial favorise le succès académique des scientifiques féminines par rapport aux bourses salariales uniquement.Étude de cohorte rétrospective.Programmes nationaux de formation et de bourses salariales pour les chercheurs et les chercheurs cliniciens du Canada.La cohorte KRESCENT (n = 59; 2005-2017), la cohorte PCCCSE (n = 58; 2002-2015) et les récipiendaires d’une bourse salariale des IRSC (n = 571; 2005-2015) destinées aux boursiers postdoctoraux (BPD) et aux nouveaux chercheurs (NC).Le succès du financement des subventions de fonctionnement nationales, l’obtention d’un poste de professeur adjoint à l’université pour les BPD ou l’obtention d’une promotion au poste de professeur agrégé pour les NC.La répartition des genres dans chaque cohorte a été déterminée à l’aide du prénom et de Namepedia, et a été examinée en fonction du statut (BPD ou NC). Les résultats des stagiaires ont été décrits selon le genre et le niveau de formation.Dans le cas des BPD, les cohortes KRESCENT et IRSC étaient plutôt équilibrées (44 % d’hommes [12/27] pour KRESCENT et 47 % [55/116] de femmes pour IRSC). Les femmes BPD étaient plus nombreuses dans la cohorte PCCCSE (13/20 [65 %]). Du côté des NC, les femmes étaient majoritaires dans les cohortes KRESCENT et PCCCSE (respectivement 59 % [19/32] et 58 % [22/38] de femmes) et les hommes étaient plus nombreux dans la cohorte IRSC (64 % d’hommes [290/455]; 36 % de femmes [165/455] [p = 0,01]). Nous avons observé un taux élevé de réussite des subventions de fonctionnement chez les NC (91 à 95 %) dans toutes les cohortes, sans égard au genre. Une forte proportion de BPD du PCCCSE avaient obtenu un poste de professeur adjoint (18/20 [90 %]); ceci pourrait s’expliquer en partie par le plus long suivi (9,3 ± 3 ans) comparativement aux BPD du KRESCENT (7/27 [26 %]; 0,88 ± 4,5 ans). Ces données n’étaient pas disponibles pour les BPD des IRSC. On a vu une augmentation des promotions à des postes de professeurs agrégés pour les nouvelles chercheuses de la cohorte KRESCENT (p = 0,02, pour 0,25 ± 3,2 ans de suivi). Les NC du PCCCSE présentaient un taux élevé de promotions (37/38 [97 %]; 6,9 ± 3,6 ans de suivi), indépendamment du genre. Une tendance globale pour un plus grand nombre d’hommes poursuivant des recherches biomédicales a été observée.Parmi les limites, on compte la taille et l’hétérogénéité des cohortes KRESCENT et PCCCSE; de possibles erreurs de classification dues à l’attribution du genre par le prénom; le manque de données sur les bassins respectifs de candidats; l’incapacité d’examiner l’intersectionnalité avec le genre, l’origine ethnique et l’orientation sexuelle.Le rendement global des stagiaires dans l’ensemble des programmes est remarquable, quel que soit leur genre, par rapport aux normes communautaires. Les programmes de formation de KRESCENT et PCCCSE ont démontré un succès équilibré chez leurs BPD et NC, tandis que les récipiendaires d’une bourse des IRSC ont montré une plus faible représentation de chercheuses tant chez les BPD et les NC. Cette étude exploratoire met en lumière la pertinence d’approches de formation programmatique comme le KRESCENT pour soutenir et retenir les scientifiques féminines dans le domaine académique pendant la difficile période de transition entre le statut de boursière postdoctorale et celui de nouvelle chercheuse.

Understanding the events leading to allorecognition and the subsequent effector pathways engaged is key for the development of strategies to prolong graft survival. Optimizing patient outcomes will require 2 major advancements: (1) minimizing premature death with a functioning graft in the patients with stable graft function, and (2) maximizing graft survival by avoiding the aforementioned allorecognition. This necessitates personalized immunosuppression to avoid known metabolic side effects, risk for infection, and malignancy, while holding the alloimmune system in check. Since the beginning of transplant a key strategy to achieve this goal is to minimize HLA mismatching between donor and recipient. What has not evolved is any refinement in our evaluation of HLA relatedness between donor and recipient when HLA mismatch exists. Donor-recipient HLA mismatch at the amino acid level can now be determined. These mismatches serve as potential epitopes for de novo donor specific antibody development and correlate with late rejection and graft loss. It is in this context that HLA epitope analysis is considered as a strategy to permit safe immunosuppression minimization to improve patient outcomes through: (1) improved allocation schemes that favor donor-recipient pairs with a low HLA epitope mismatch load (especially at the class II loci) or avoiding specific epitope mismatches known to be highly immunogenic and (2) immunosuppressive minimization in patients with low epitope mismatch loads or without highly immunogenic epitope mismatches.

The urinary CXC chemokine ligand (CXCL)10 detects renal transplant inflammation noninvasively, but has limited sensitivity and specificity. In this study, we performed urinary proteomic analysis to identify novel biomarkers that may improve the diagnostic performance of urinary CXCL10 for detecting alloimmune inflammation in renal transplant patients.In preliminary studies, adult renal transplant patients with normal histology (n = 5), interstitial fibrosis and tubular atrophy (n = 6), subclinical (n = 6) and clinical rejection (n = 6), underwent in-depth urine protein compositional analysis with LC-MS/MS, and matrix metalloproteinase-7 (MMP7) were identified as a potential candidate for the diagnosis of renal allograft inflammation. Urine MMP7 performance was then studied in a larger, prospective adult renal transplant population (n = 148 urines from n = 133 patients) with matched surveillance/indication biopsies. The diagnostic performance of urinary MMP7 and CXCL10 in combination was next evaluated using concordance (C-) statistics, net reclassification improvement and integrated discrimination improvement indices, to determine whether it was better than CXCL10 alone.Urinary MMP7:creatinine (Cr) was lower in normal transplants compared to those with inflammation: glomerulonephritis (P = 0.009), viral nephropathies (P = 0.002), interstitial fibrosis and tubular atrophy and inflammation (P = 0.04), borderline (P = 0.08), subclinical (P = 0.01) and clinical rejection (P = 0.0006), and acute tubular necrosis (P0.0001). Urinary MMP7:Cr and CXCL10:Cr significantly distinguished noninflamed from inflamed biopsies (area under the curve, 0.74 and 0.70, respectively). The addition of urinary MMP7:Cr to CXCL10:Cr improved the diagnostic performance for subclinical and clinical inflammation/injury by integrated discrimination improvement (P = 0.002) and net reclassification improvement (P = 0.006) analyses.Urinary MMP7:Cr improves the overall diagnostic performance of urinary CXCL10:Cr for distinguishing normal histology from subclinical and clinical inflammation/injury, but not subclinical inflammation alone.

Predicting allograft failure in kidney transplant recipients can help plan renal replacement therapy and guide patient-provider communication. The kidney failure risk equation (KFRE) accurately predicts the need for dialysis in patients with chronic kidney disease (CKD), but has not been validated in kidney transplant recipients.We sought to validate the 4-variable KFRE (age, sex, estimated glomerular filtration rate [eGFR], and urine albumin-to-creatinine ratio [ACR]) for prediction of 2- and 5-year death-censored allograft failure.Retrospective cohort study.Four independent North American Cohorts from Ontario, Canada; Alberta, Canada; Manitoba, Canada; and Wisconsin, United States, between January 1999 and December 2017.Adult kidney transplant patients at 1-year posttransplantation.Kidney failure risk as measured by the KFRE (eGFR, urine ACR, age, and sex).We included all adult patients who had at least 1 serum creatinine and at least 1 urine ACR measurement approximately 1 year following kidney transplantation. The performance of the KFRE was evaluated using the area under the receiver operating characteristic curve (C-statistic). C-statistics from the 4 cohorts were meta-analyzed using random-effects models.A total of 3659 patients were included. Pooled C-statistics were good in the entire population, at 0.81 (95% confidence interval: 0.72-0.91) for the 2-year KFRE and 0.73 (0.67-0.80) for the 5-year KFRE. Discrimination improved among patients with poorer kidney function (eGFR45 mL/min/1.73 mThe KFRE does not predict episodes of acute rejection and there was heterogeneity between cohorts.The KFRE accurately predicts kidney failure in kidney transplant recipients at 1-year posttransplantation. Further validation in larger cohorts with longer follow-up times can strengthen the case for clinical implementation.En transplantation rénale, la capacité de prévoir la défaillance du greffon permet de planifier une thérapie de remplacement rénal et de guider la communication entre le patient et son soignant. L’équation KFRE (Nous souhaitions valider le pouvoir prédictif de l’équation KFRE à 4 variables (âge, sexe, débit de filtration glomérulaire estimé [DFGe] et rapport albumine-créatine urinaire [RAC]) quant à la défaillance du greffon après deux ans et cinq ans.Étude de cohorte rétrospective.Quatre cohortes indépendantes d’Amérique du Nord : trois provinces canadiennes (Ontario, Alberta et Manitoba) et un état américain (Wisconsin) entre janvier 1999 et décembre 2017.Des adultes receveurs d’une greffe rénale, un an après l’intervention.Le risque d’évolution vers l’insuffisance rénale, tel que mesuré par l’équation KFRE (DFGe, RAC urinaire, âge et sexe).Ont été inclus tous les patients adultes ayant eu au moins une mesure de la créatinine sérique et du RAC urinaire environ un an après la greffe. La performance de la KFRE a été évaluée par la surface sous la courbe ROC (statistique C). Des modèles à effets aléatoires ont été employés pour la méta-analyse des statistiques C pour les quatre cohortes.Un total de 3 659 patients a été inclus. Les statistiques C regroupées ont été bonnes dans l’ensemble de la population étudiée, avec des valeurs de 0,81 (intervalle de confiance à 95 % : 0,72-0,91) pour la prédiction sur deux ans et de 0,73 (0,67-0,80) pour la prédiction sur cinq ans. La discrimination s’est avérée encore meilleure pour les patients qui présentaient une plus faible fonction rénale (DFGe45 ml/min/1,73 mLa KFRE ne peut prédire les épisodes de rejet aigu et les cohortes étudiées comportaient une grande hétérogénéité.L’équation KFRE prédit avec exactitude le risque de défaillance du greffon dans notre population de receveurs d’une greffe rénale, un an après l’intervention. Poursuivre la validation dans de plus vastes cohortes et pour des temps de suivi prolongés viendrait appuyer le cas en vue de son application clinique.

Background Antibody-mediated rejection is a major cause of premature graft loss in kidney transplantation. Multiple scoring systems are available to assess the HLA mismatch between donors and recipients at the molecular level; however, their correlation with the development of de novo donor-specific antibody (dnDSA) has not been compared in recipients on active immunosuppression. Methods HLA-DRβ1/3/4/5/DQα1β1 molecular mismatch was determined using eplet analysis, amino acid mismatch, and electrostatic mismatch for 596 renal transplant recipients and correlated with HLA-DR/DQ dnDSA development. The molecular mismatch scores were evaluated in multivariate models of posttransplant dnDSA-free survival. Results Eplet mismatch correlated with amino acid mismatch and electrostatic mismatch (R2 = 0.85-0.96). HLA-DR dnDSA-free survival correlated with HLA-DR eplet mismatch (hazards ratio [HR], 2.50 per 10 eplets mismatched; P < 0.0001), amino acid mismatch (HR, 1.49 per 10 amino acids mismatched; P < 0.0001), and electrostatic mismatch (HR, 1.23 per 10 units mismatched; P < 0.0001). HLA-DQ dnDSA-free survival correlated with HLA-DQ eplet mismatch (HR, 1.98 per 10 eplets mismatched; P < 0.0001), amino acid mismatch (HR, 1.24 per 10 amino acids mismatched; P < 0.0001), and electrostatic mismatch (HR, 1.14 per 10 units mismatched; P < 0.0001). All 3 methods were significant multivariate correlates of dnDSA development after adjustment for recipient age, baseline immunosuppression, and nonadherence. Conclusions HLA molecular mismatch represents a precise method of alloimmune risk assessment for renal transplant patients. The method used to determine the molecular mismatch is likely to be driven by familiarity and ease of use as highly correlated results are produced by each method., In order to assess alloimmune risk in kidney transplant recipiennts, the authors compare 3 methods evaluating HLA molecular mismatch (HLA-DG eplet, amino acid and electrostatic) which all correlate with adjusted dnDSA development. Supplemental digital content is available in the text.

Urinary CXCL10 and metabolites are biomarkers independently associated with TCMR. We sought to test whether these biomarkers fluctuate in association with histological severity of TCMR over short time frames. Forty-nine pairs of renal biopsies obtained 1-3 months apart from 40 pediatric renal transplant recipients were each scored for TCMR acuity score (i + t; Banff criteria). Urinary CXCL10:Cr and TCMR MDS were obtained at each biopsy and were tested for association with changes between biopsies in acuity, estimated GFR (ΔeGFR), and 12-month ΔeGFR. Sequential biopsies were obtained 1.8 ± 0.8 months apart. Biopsy 1 was usually obtained under protocol (75%), and 62% percent had evidence of TCMR. Using each biopsy pair for comparison, ΔeGFR did not predict change in acuity. By contrast, change in acuity was significantly correlated with change in urinary CXCL10:Cr (ρ 0.45, P = .003) and MDS (ρ 0.29, P = .04) between biopsies. The 12-month ΔeGFR was not predicted by TCMR acuity or CXCL10:Cr at Biopsy 2; however, an inverse correlation was seen with urinary MDS (ρ -0.35; P = .02). Changes in eGFR correlate poorly with evolving TCMR acuity on histology. Urinary biomarkers may be superior for non-invasive monitoring of rejection, including histological response to therapy, and may be prognostic for medium-term function.

The current immunosuppressive pipeline in kidney transplantation is limited. In part, this is due to excellent one-year allograft outcomes with the current standard of care (ie, calcineurin inhibitor in combination with anti-proliferative agents). Despite this success, a recent Federal government-sponsored systematic review has identified gaps/limits in the evidence of what constitutes optimal calcineurin inhibitor use in the short- and long-term. Moreover, recent empiric approaches to minimize/withdraw/convert from calcineurin inhibitors have come with the price of increased alloreactivity. As the time horizon to replace calcineurin inhibitors on a global scale may be distant, the transplant community should seize the opportunity to develop ways to personalize calcineurin inhibitor immunosuppression to the individual-transitioning from empiricism to precision. The authors argue in this viewpoint that the path to precision will require measures capable of detecting subclinical alloreactivity to define adequacy of immunosuppression, as well as novel genetic analytics to accurately define alloimmune risk at the individual level-both approaches will require validation in clinical trials.

Concerns about adverse effects of calcineurin inhibitors (CNIs) have prompted development of protocols that minimize their use. Whereas previous CNI withdrawal trials in heterogeneous cohorts showed unacceptable rates of acute rejection (AR), we hypothesized that we could identify individuals capable of tolerating CNI withdrawal by targeting immunologically quiescent kidney transplant recipients. The Clinical Trials in Organ Transplantation-09 Trial was a randomized, prospective study of nonsensitized primary recipients of living donor kidney transplants. Subjects received rabbit antithymocyte globulin, tacrolimus, mycophenolate mofetil, and prednisone. Six months post-transplantation, subjects without de novo donor-specific antibodies (DSAs), AR, or inflammation at protocol biopsy were randomized to wean off or remain on tacrolimus. The intended primary end point was the change in interstitial fibrosis/tubular atrophy score between implantation and 24-month protocol biopsies. Serially collected urine CXCL9 ELISA results were correlated with outcomes. The study was terminated prematurely because of unacceptable rates of AR (4 of 14) and/or de novo DSAs (5 of 14) in the tacrolimus withdrawal arm. Positive urinary CXCL9 predated clinical detection of AR by a median of 15 days. Analyses showed that >16 HLA-DQ epitope mismatches and pretransplant, peripheral blood, donor-reactive IFN-γ ELISPOT assay results correlated with development of DSAs and/or AR on tacrolimus withdrawal. Although data indicate that urinary CXCL9 monitoring, epitope mismatches, and ELISPOT assays are potentially informative, complete CNI withdrawal must be strongly discouraged in kidney transplant recipients who are receiving standard-of-care immunosuppression, including those who are deemed to be immunologically quiescent on the basis of current clinical and laboratory criteria.

Understanding rates and determinants of clinical pathologic progression for recipients with de novo donor-specific antibody (dnDSA), especially subclinical dnDSA, may identify surrogate endpoints and inform clinical trial design. A consecutive cohort of 508 renal transplant recipients (n = 64 with dnDSA) was studied. Recipients (n = 388) without dnDSA or dysfunction had an eGFR decline of -0.65 mL/min/1.73 m(2) /year. In recipients with dnDSA, the rate eGFR decline was significantly increased prior to dnDSA onset (-2.89 vs. -0.65 mL/min/1.73 m(2) /year, p

HLA antibodies, and specifically donor-specific-HLA antibodies, play a key role in transplant-related diagnostics and decision-making. It is now clear that the simple differentiation between absence and presence of HLA donor-specific antibodies does not provide sufficient granularity in all clinical circumstances. It addition, knowledge of HLA antibody strength has potential utility at different stages of recipient evaluation along the transplant timeline from initial pretransplant evaluation, evaluation of a specific potential donor, and posttransplant monitoring for de novo donor-specific antibodies. Here we compare data evaluating HLA antibody strength using the conventional IgG-mean fluorescence intensity approach with serial dilution studies (titration) and of C1q binding (C1q-mean fluorescence intensity). The added value of titration studies along the 3 milestones of the transplant cycle is emphasized.

Background Urinary CXC chemokine ligand 10 (CXCL10) is a promising biomarker for subclinical tubulointerstitial inflammation, but limited data exist regarding its correlation with (micro)vascular inflammation. Furthermore, no study has evaluated whether concomitant serum CXCL10 improves the discrimination for (micro)vascular inflammation. Methods We investigated whether serum/urinary CXCL10 reflect subclinical inflammation within different renal compartments. Patients (n = 107) with 107 surveillance biopsies were classified as: normal histology (n = 47), normal histology with polyomavirus BK (BKV) or cytomegalovirus (CMV) viremia (n = 17), moderate-severe tubulointerstitial inflammation (tubulitis ≥2, n = 18), pure microvascular inflammation (n = 15), and isolated v lesions (n = 10). Serum and urinary CXCL10 Enzyme-linked Immunosorbent Assay was performed. An independent validation set was evaluated for urine CXCL10: normal histology (n = 14), normal histology with BKV or CMV viremia (n = 19), tubulitis ≥2 (n = 15), pure microvascular inflammation (n = 41), and isolated v lesions (n = 14). Results Elevated urinary CXCL10 reflected inflammation within the tubulointerstitial (urinary CXCL10/creatinine, 1.23 ng/mmol vs 0.46 ng/mmol; P = 0.02; area under the curve, 0.69; P = 0.001) and microvascular compartments (urinary CXCL10/creatinine, 1.72 ng/mmol vs 0.46 ng/mmol; P = 0.03; area under the curve, 0.69; P = 0.02) compared to normal histology. Intriguingly, urinary CXCL10 was predominantly elevated with peritubular capillaritis, but not glomerulitis (P = 0.04). Furthermore, urinary CXCL10 corresponded with BKV, but not CMV viremia (P = 0.02). These urine CXCL10 findings were confirmed in the independent validation set. Finally, serum CXCL10 was elevated with BKV and CMV viremia but was not associated with microvascular or vascular inflammation (P ≥ 0.19). Conclusions Urinary CXCL10 reflects subclinical inflammation within the tubulointerstitial and peritubular capillary spaces, but not the vascular/systemic compartments; this was consistent with BKV (tubulointerstitial) and CMV viremia (systemic). Serum CXCL10 was not a useful marker for (micro)vascular inflammation.

Despite more than two decades of use, the optimal maintenance dose of tacrolimus for kidney transplant recipients is unknown. We hypothesized that HLA class II de novo donor-specific antibody (dnDSA) development correlates with tacrolimus trough levels and the recipient’s individualized alloimmune risk determined by HLA-DR/DQ epitope mismatch. A cohort of 596 renal transplant recipients with 50,011 serial tacrolimus trough levels had HLA-DR/DQ eplet mismatch determined using HLAMatchmaker software. We analyzed the frequency of tacrolimus trough levels below a series of thresholds 6 months before dnDSA development in the same patients. Recipients with a high-risk HLA eplet mismatch score were less likely to tolerate low tacrolimus levels without developing dnDSA. We conclude that HLA-DR/DQ eplet mismatch and tacrolimus trough levels are independent predictors of dnDSA development. Recipients with high HLA alloimmune risk should not target tacrolimus levels

De novo donor-specific antibody (dnDSA) develops in 15-25% of renal transplant recipients within 5 years of transplantation and is associated with 40% lower graft survival at 10 years. HLA epitope matching is a novel strategy that may minimize dnDSA development. HLAMatchmaker software was used to characterize epitope mismatches at 395 potential HLA-DR/DQ/DP conformational epitopes for 286 donor-recipient pairs. Epitope specificities were assigned using single antigen HLA bead analysis and correlated with known monoclonal alloantibody epitope targets. Locus-specific epitope mismatches were more numerous in patients who developed HLA-DR dnDSA alone (21.4 vs. 13.2, p < 0.02) or HLA-DQ dnDSA alone (27.5 vs. 17.3, p < 0.001). An optimal threshold for epitope mismatches (10 for HLA-DR, 17 for HLA-DQ) was defined that was associated with minimal development of Class II dnDSA. Applying these thresholds, zero and 2.7% of patients developed dnDSA against HLA-DR and HLA-DQ, respectively, after a median of 6.9 years. Epitope specificity analysis revealed that 3 HLA-DR and 3 HLA-DQ epitopes were independent multivariate predictors of Class II dnDSA. HLA-DR and DQ epitope matching outperforms traditional low-resolution antigen-based matching and has the potential to minimize the risk of de novo Class II DSA development, thereby improving long-term graft outcome.

PURPOSE OF REVIEW To summarize the evidence supporting the negative impact of de novo donor-specific antibodies (dnDSA) in renal transplantation and to describe the natural history associated with the development of dnDSA. RECENT FINDINGS Recent studies have increased our appreciation of the risk factors that predispose to dnDSA while illuminating how these risk factors may relate to the pathophysiology underlying its development. In addition, details regarding the natural history of dnDSA are now available in the context of the different clinical pathologic phenotypes that occur in the patients in whom it develops. Common pitfalls in defining and monitoring dnDSA, when understood, may provide some explanation for the heterogeneity in published studies. SUMMARY Recognizing that dnDSA is a major cause of late graft loss, and, more importantly, is detectable in many cases long before dysfunction or graft loss occurs, identifies an opportunity to intervene and change the outcome for the patient.

BACKGROUND Early noninvasive markers that identify patients at risk of renal allograft loss may stratify patients for more intensive monitoring or therapy. CCL2 is a CCR2 receptor chemokine that is a chemoattractant protein for monocytes/macrophages, T cells, and natural killer cells. We have previously demonstrated in a multicenter cohort that urinary CCL2 at 6 months is an independent predictor for the development of IFTA at 24 months. The goal of this study was to determine if early urinary CCL2 is a predictor of graft loss in an independent patient cohort. METHODS A prospective, observational cohort study was conducted in the Transplant Manitoba Adult Kidney Program (n=231 patients) from 1997 to 2008. Six-month urinary CCL2 was measured by ELISA, corrected for urinary creatinine, and correlated with long-term graft outcomes. RESULTS Urine CCL2: Cr at 6 months was significantly associated with death-censored graft loss (HR, 2.42; 95% CI, 1.54-3.82, P

BACKGROUND Early prognostic markers that identify high-risk patients could lead to increased surveillance, personalized immunosuppression, and improved long-term outcomes. The goal of this study was to validate 6-month urinary chemokine ligand 2 (CCL2) as a noninvasive predictor of long-term outcomes and compare it with 6-month urinary CXCL10. METHODS A prospective, observational renal transplant cohort (n = 185; minimum, 5-year follow-up) was evaluated. The primary composite outcome included 1 or more: allograft loss, renal function decline (>20% decrease estimated glomerular filtration rate between 6 months and last follow-up), and biopsy-proven rejection after 6 months. CCL2/CXCL10 are reported in relation to urine creatinine (ng/mmol). RESULTS Fifty-two patients (52/185, 28%) reached the primary outcome at a median 6.0 years, and their urinary CCL2:Cr was significantly higher compared with patients with stable allograft function (median [interquartile range], 38.6 ng/mmol [19.7-72.5] vs 25.9 ng/mmol [16.1-45.8], P = 0.009). Low urinary CCL2:Cr (≤70.0 ng/mmol) was associated with 88% 5-year event-free survival compared with 50% with high urinary CCL2:Cr (P < 0.0001). In a multivariate Cox-regression model, the only independent predictors of the primary outcome were high CCL2:Cr (hazard ratio [HR], 2.86; 95% confidence interval [95% CI], 1.33-5.73) and CXCL10:Cr (HR, 2.35; 95% CI, 1.23-4.88; both P = 0.009). Urinary CCL2:Cr/CXCL10:Cr area under the curves were 0.62 (P = 0.001)/0.63 (P = 0.03), respectively. Time-to-endpoint analysis according to combined high or low urinary chemokines demonstrates that endpoint-free survival depends on the overall early chemokine burden. CONCLUSIONS This study confirms that urinary CCL2:Cr is an independent predictor of long-term allograft outcomes. Urinary CCL2:Cr/CXCL10:Cr alone have similar prognostic performance, but when both are elevated, this suggests a worse prognosis. Therefore, urinary chemokines may be a useful tool for timely identification of high-risk patients.

Background The goal of this study was to characterize urinary metabolomics for the noninvasive detection of cellular inflammation and to determine if adding urinary chemokine ligand 10 (CXCL10) improves the overall diagnostic discrimination. Methods Urines (n = 137) were obtained before biopsy in 113 patients with no (n = 66), mild (borderline or subclinical; n = 58), or severe (clinical; n = 13) rejection from a prospective cohort of adult renal transplant patients (n = 113). Targeted, quantitative metabolomics was performed with direct flow injection tandem mass spectrometry using multiple reaction monitoring (ABI 4000 Q-Trap). Urine CXCL10 was measured by enzyme-linked immunosorbent assay. A projection on latent structures discriminant analysis was performed and validated using leave-one-out cross-validation, and an optimal 2-component model developed. Chemokine ligand 10 area under the curve (AUC) was determined and net reclassification index and integrated discrimination index analyses were performed. Results PLS2 demonstrated that urinary metabolites moderately discriminated the 3 groups (Cohen κ, 0.601; 95% confidence interval [95% CI], 0.46-0.74; P < 0.001). Using binary classifiers, urinary metabolites and CXCL10 demonstrated an AUC of 0.81 (95% CI, 0.74-0.88) and 0.76 (95% CI, 0.68-0.84), respectively, and a combined AUC of 0.84 (95% CI, 0.78-0.91) for detecting alloimmune inflammation that was improved by net reclassification index and integrated discrimination index analyses. Urinary CXCL10 was the best univariate discriminator, followed by acylcarnitines and hexose. Conclusions Urinary metabolomics can noninvasively discriminate noninflamed renal allografts from those with subclinical and clinical inflammation, and the addition of urine CXCL10 had a modest but significant effect on overall diagnostic performance. These data suggest that urinary metabolomics and CXCL10 may be useful for noninvasive monitoring of alloimmune inflammation in renal transplant patients.

International audience; C1q-binding ability may indicate the clinical relevance of de novo donor-specific anti-HLA antibodies (DSA). This study investigated the incidence and risk factors for the appearance of C1q-binding de novo DSA and their long-term impact. Using Luminex Single Antigen Flow Bead assays, 346 pretransplant nonsensitized kidney recipients were screened at 2 and 5 years after transplantation for de novo DSA, which was followed when positive by a C1q Luminex assay. At 2 and 5 years, 12 (3.5%) and eight (2.5%) patients, respectively, had C1q-binding de novo DSA. De novo DSA mean fluorescence intensity \textgreater6237 and \textgreater10,000 at 2 and 5 years, respectively, predicted C1q binding. HLA mismatches and cyclosporine A were independently associated with increased risk of C1q-binding de novo DSA. When de novo DSA were analyzed at 2 years, the 5-year death-censored graft survival was similar between patients with C1q-nonbinding de novo DSA and those without de novo DSA, but was lower for patients with C1q-binding de novo DSA (P=0.003). When de novo DSA were analyzed at 2 and 5 years, the 10-year death-censored graft survival was lower for patients with C1q-nonbinding de novo DSA detected at both 2 and 5 years (P\textless0.001) and for patients with C1q-binding de novo DSA (P=0.002) than for patients without de novo DSA. These results were partially confirmed in two validation cohorts. In conclusion, C1q-binding de novo DSA are associated with graft loss occurring quickly after their appearance. However, the long-term persistence of C1q-nonbinding de novo DSA could lead to lower graft survival.

Predicting long-term outcomes in renal transplant recipients is essential to optimize medical therapy and determine the frequency of posttransplant histologic and serologic monitoring. Nonadherence and human leukocyte antigen (HLA) mismatch are risk factors that have been associated with poor long-term outcomes and may help individualize care. In the present study, class II HLA mismatches were determined at the HLA epitope level in 195 renal transplant recipients in whom medication adherence was prospectively measured using electronic monitors in medication vial caps. Recipients were grouped by medication adherence and high (≥10 HLA-DR, ≥17 HLA-DQ) or low epitope-mismatch load. We found that the combination of higher epitope mismatch and poor adherence acted synergistically to determine the risk of rejection or graft loss. Nonadherent recipients with HLA-DR epitope mismatch ≥10 had increased graft loss (35% vs. 8%, p

PURPOSE OF REVIEW To summarize the evidence concerning human leukocyte antigen (HLA) epitope mismatch analysis as a means to predict donor-specific antibody (DSA) development and allograft survival. RECENT FINDINGS HLA epitope mismatch analysis outperforms traditional whole molecule antigen mismatch for predicting the risk of de-novo DSA development. By analyzing the number of epitope mismatches for a given donor-recipient pair, thresholds have been identified to stratify patients into those at high or low risk of de-novo DSA development. Epitope specificity assignment in patients who develop de-novo DSA compared with controls who do not provides an opportunity to study the relative immunogenicity of mismatched HLA epitopes. SUMMARY Recognizing that de-novo DSA is a major cause of graft loss, HLA epitope mismatch analysis is a strategy to minimize de-novo DSA development and improve long-term graft survival.

BACKGROUND We have demonstrated that 6-month urinary CCL2: Cr is a predictor of interstitial fibrosis and tubular atrophy (IFTA) on 24-month biopsy and death-censored graft loss. However, IFTA is no longer considered prognostically significant, whereas patients with graft loss frequently have interstitial fibrosis and inflammation (IF+i=ci>0+i>0). As early CCL2: Cr predicts late graft loss, the goal of this study was to determine if 6-month urinary CCL2: Cr was a predictor of IF+i at 24 months. METHODS Urinary CCL2 at 6 months was measured with ELISA and correlated with IF+i on 24-month surveillance biopsies from a prospective, multicenter adult renal transplant cohort (n=111). RESULTS Six-month urinary CCL2: Cr was significantly higher in IF+i and transplant glomerulopathy patients compared with normal histology at 24 months. By multivariate analysis, 6-month urinary CCL2: Cr was independently correlated with IF+i at 24 months (OR 2.78, 95% CI 1.38-6.12, AUC 0.695, P=0.003). Six-month urinary CCL2: Cr was also an independent correlate of 6-month IF+i (OR 1.99, 95% CI 1.03-4.18, AUC 0.63, P=0.04). Six-month urinary CCL2: Cr distinguished noninflamed renal tissue (normal, fibrosis) from IF+i with a sensitivity/specificity of 0.71/0.62 at a cutoff of 15 ng CCL2/mmol Cr (AUC 0.695, P=0.003, n=91). CONCLUSIONS Urinary CCL2: Cr may be useful for the noninvasive identification of patients with or at risk for IF+i. These patients may benefit from avoidance of drug minimization/withdrawal protocols and more intensive post-transplant surveillance. Furthermore, urinary CCL2: Cr may also identify individuals who may benefit from novel interventional trials targeting IF+i.

Background Secondary hyperparathyroidism is a common complication of end-stage renal disease (ESRD), which occurs as a result of hyperphosphataemia, hypovitaminosis D and hypocalcaemia. Chronic hyperparathyroidism can result in osteitis fibrosis cystica, also known as brown tumours. Spinal cord compression from a brown tumour is a rare emergency and of the eight reported cases in the literature, this represents the first case while undergoing treatment with sevelamer and cinacalcet. Although cinacalcet may have a role in the metabolic control of hyperparathyroidism, caution needs to be taken in delay or avoidance of parathyroidectomy in severe cases, as it may cause delays in necessary therapy.

De novo donor-specific antibodies ( dn DSA) that develop after renal transplantation are independent predictors of allograft loss. However, it is unknown if dn DSA C1q status or titer at the time of first detection can independently predict allograft outcomes. In 70 renal transplant recipients who developed dn DSA we performed LABScreen single antigen bead assays using: neat, neat with ethylenediaminetetraacetic acid (EDTA), three dilutions after EDTA treatment (1:16, 1:64, 1:1024) and the C1q assay (neat sera). Histologic and clinical outcomes were correlated with the C1q assay or dn DSA titer. C1q positivity correlated with dn DSA titer (p dn DSA (p dn DSA development, but did not predict T-cell mediated rejection (TCMR) or antibody mediated rejection (ABMR). De novo DSA titer correlated with glomuerulitis, interstitial inflammation, tubulitis, peritubular capillaritis, and C4d scores, and predicted TCMR (p dnDSA development or other known predictors of post-dnDSA graft loss (i.e. clinical phenotype or non-adherence) neither C1q status nor dn DSA titer were independent predictors of a composite outcome of a 50% decline in eGFR or allograft loss (Fig. 1). Therefore, at present the additional cost and time associated with these approaches is not justified in routine practise. However, in cases where a renal biopsy is not possible dn DSA titer correlates with TCMR, and AMBR, and may assist in risk stratification. Download high-res image (239KB) Download full-size image

Current strategies for posttransplant monitoring of kidney transplants consist of measuring serial serum creatinine levels, clinical follow-up, and in some programs, protocol biopsies. These strategies may be insufficient to predict acute rejection in kidney transplants, which remains the major factor affecting long-term transplant outcomes. Immune monitoring may conceptually be divided into strategies for detecting humoral rejection (eg, donor-specific antibody) or cellular rejection. Cellular rejection markers may be separated further into those related to cytotoxic T lymphocytes (granzyme A/B, perforin, Fas ligand, and serpin B9), regulatory T cells (FOXP3), and CD4 T cells (the chemokines CXCL9, CXCL10, CXCL11, CCL2, and fractalkine, as well as TIM-3). Finally, transcriptomic changes and renal tubular injury markers also may be useful for detecting early inflammatory changes post–kidney transplant. Ultimately, novel strategies for monitoring the immune status of the kidney transplant may lead to early therapeutic intervention and improved kidney transplant outcomes.

In May, 2009, a 32-year-old man presented to our emergency department with dyspnoea, productive cough with limited haemoptysis, diff use myalgia, and malaise. The symptoms had started 24 h earlier; he denied fever or chills. He had end-stage renal disease secondary to focal segmental glomerular sclerosis and had fl uid overload because he had missed three of his last eight haemodialysis treatments. His vital signs were: blood pressure 162/94 mm Hg, respiratory rate 20 breaths per min, temperature 37·5°C, oxygen saturation 95% with supplemental oxygen. Physical examination showed signs of volume overload and bilateral coarse crackles in the lungs. Chest radiography at admission showed bilateral airspace opacifi cation and vascular redistribution (fi gure). He was treated with antibiotics and urgent haemodialysis, during which 6·1 L of fl uid was removed. An additional 5·1 L were removed during a second dialysis treatment, but respiratory status did not improve; the patient was intubated and mechanically ventilated on day 4. Although afebrile, given the lack of improvement in clinical status, on day 4 of admission our patient was placed in respiratory isolation and a 5 day course of oseltamivir was started. Bronchoscopy showed no endobronchial lesions or alveolar haemorrhage. Bronchoalveolar samples were positive for infl uenza H1N1 virus by PCR. ICU admission was later complicated by Escherichia coli nosocomial pneumonia and tracheostomy. As of September, 2009, the patient has been extubated and discharged from hospital. As of Sept 6, 2009, more than 277 600 laboratoryconfi rmed cases of pandemic H1N1 infl uenza A have been reported to WHO. Whether the presentation and clinical course of H1N1 infl uenza is similar in the dialysis population to the general population is currently unknown. Observations from this case (and another, not described here) suggest that presentation in dialysis patients may diff er; most H1N1 infl uenza cases meet the defi nition for infl uenza-like illness of fever plus cough or sore throat—this did not transpire in two of our dialysis patients. Uraemia-induced immune dysfunction might lead to this atypical presentation in dialysis patients. Worryingly, the diagnosis of infl uenza was not considered until our patient failed to respond to fl uid removal and antibiotics. Haemodialysis patients are close to one another during their dialysis treatment, increasing their exposure to transmission of respiratory infection. Fortunately, to date no known cases have been directly linked to our case. The current recommendations for treat ment of H1N1 infl uenza are oseltamivir or zanamivir. Because oseltamivir is eliminated by the kidneys, a reduced dose of 75 mg orally 3 times weekly after haemodialysis is recommended, although postdialysis dosing of 30 mg daily has been shown to achieve adequate clinical exposure to the active form of the drug in haemodialysis patients. These results were obtained in patients dialysed on a low-fl ux dialyser, therefore this dose may be insuffi cient when high-fl ux dialyzers are used because of greater drug clearance. Because our centre uses only high-fl ux dialysers, we administered the increased dose of 75 mg daily for 5 days. H1N1 infl uenza A is an important diff erential diagnosis in dialysis patients who are short of breath or febrile. Our case highlights the potential impact of infl uenza in this vulnerable population.