The team of the Paris Transplant Group has been awarded at the ESOT 2019 congress in Copenhagen for its many contribution in the field of transplantation. 

The Prize is given to a single Institution having submitted at least 5 abstracts for the event and granted with the best score. The Paris Transplant Group is very pleased to won this European award twice in a row. 

Check out the contribution submitted by the Group on the ESOT website: esotcongress.org.

Olivier Aubert is awarded for its work on "Disparities in the acceptance of deceased donor kidney and consequences for transplant access: nationwide analysis of practice in the US and France". The co-authors of this work are affiliated to Paris Translational Center for Organ Transplantation,  the University of Pennsylvania, Philadelphia, US ;  the Agence de la Biomédecine of France and two Parisian transplantation centres: Necker Hospital and Saint Louis Hospital.

Find more information about the study in the article published in the JAMA journal: access the full study.

Using a new approach based on validated analytical methods and computer simulations, this work revealed that French transplant centres are much more likely to transplant kidneys from older donors than their American counterparts, and that this effectively increases the number of patients transplanted. 

During the event, a specific symposium is held for the EU Train-ESOT that highlights the methodological and statistical risks clinical researchers can face in the field of transplantation. Carmen Lefaucheur, Olivier Aubert, Alexandre Loupy, Yassine Bouatou, Dany Anglicheau and Christophe Legendre are invited to speak during this event to present the future of patient care in transplantation.
Check the poster submitted by Marc Raynaud here. 

You can follow the event through social media with the hashtag #ESOT2019 and @ParisTxGroup.

New research conducted by the Paris Translational Research Center for Organ Transplantation team could help clinicians determine which patients will have a disease that usually occurs after a kidney transplant and which are at high risk of transplant failure. The results are published today in the prestigious Journal of the American Society of Nephrology (JASN).

Transplant glomerulopathy was first described and characterized 50 years ago. It is a disease associated with the loss of a kidney transplant and common after a transplant. It affects the functional units (i. e. glomeruli) of the transplanted kidney. There is currently no treatment for this heterogeneous disease.

Abstract submissions are now open for oral and poster presentations. The deadline for the submission is the 8th of April.

During the meeting, you will be able to meet more than 1 200 professionals in HLA and the transplant field. And discover all the latest updates in immunogenetics and transplant immunology.

The BANFF Foundation for Allograft Pathology is a non-profit foundation, established in 2013. BANFF aims to further the development of the international BANFF Classification of Allograft Pathology, as well as publicize it. They also aspire to ease collaborative research in order to improve the care of transplant patient.

ASHI was founded in 1974, it is a non-profit international organization of clinical and research professionals. ASHI aims to advance the science and application of histocompatibility and immunogenetics. They also want to provide a forum for the exchange of information among scientists.

This review focuses on current standards for the management of antibody-mediated rejection in transplant recipients and identifies future directions for improving diagnostics and moving toward tailored therapeutics. Such advances require the development of pathogenesis-based approaches that combine precise characterization of the biologic properties of antibodies, noninvasive biomarkers, and allograft gene-expression profiling, which will set the stage for bringing antibody-mediated rejection into the era of precision medicine.

Background:  
Anti-human leukocyte antigen donor-specific antibodies (anti-HLA DSAs) are recognized as a major barrier to patients’ access to organ transplantation and the major cause of graft failure. The capacity of circulating anti-HLA DSAs to activate complement has been suggested as a potential biomarker for optimizing graft allocation and improving the rate of successful transplantations.
Methods and findingsTo address the clinical relevance of complement-activating anti-HLA DSAs across all solid organ transplant patients, we performed a meta-analysis of their association with transplant outcome through a systematic review, from inception to January 31, 2018. The primary outcome was allograft loss, and the secondary outcome was allograft rejection. A comprehensive search strategy was conducted through several databases (Medline, Embase, Cochrane, and Scopus).
A total of 5,861 eligible citations were identified. A total of 37 studies were included in the meta-analysis. Studies reported on 7,936 patients, including kidney (n = 5,991), liver (n = 1,459), heart (n = 370), and lung recipients (n = 116). Solid organ transplant recipients with circulating complement-activating anti-HLA DSAs experienced an increased risk of allograft loss (pooled HR 3.09; 95% CI 2.55–3.74, P = 0.001; I2 = 29.3%), and allograft rejection (pooled HR 3.75; 95% CI: 2.05–6.87, P = 0.001; I2 = 69.8%) compared to patients without complement-activating anti-HLA DSAs. The association between circulating complement-activating anti-HLA DSAs and allograft failure was consistent across all subgroups and sensitivity analyses. Limitations of the study are the observational and retrospective design of almost all included studies, the higher proportion of kidney recipients compared to other solid organ transplant recipients, and the inclusion of fewer studies investigating allograft rejection.
ConclusionsIn this study, we found that circulating complement-activating anti-HLA DSAs had a significant deleterious impact on solid organ transplant survival and risk of rejection. The detection of complement-activating anti-HLA DSAs may add value at an individual patient level for noninvasive biomarker-guided risk stratification.

A major hurdle to improving clinical care in the field of kidney transplantation is the lack of biomarkers of the response to antibody-mediated rejection (ABMR) treatment. To discover these we investigated the value of complement-binding donor-specific anti-HLA antibodies(DSAs) for evaluating the response to treatment. The study encompassed a prospective cohort of 139 kidney recipients with ABMR receiving the standard of care treatment, including plasma exchange, intravenous immunoglobulin and rituximab. Patients were systematically assessed at the time of diagnosis and three months after treatment initiation for clinical and allograft histological characteristics and anti-HLA DSAs, including their C1q-binding ability. After adjusting for clinical and histological parameters, post-treatment C1q-binding anti-HLA DSA was an independent and significant determinant of allograft loss (adjusted hazard ratio 2.57 (95% confidence interval 1.29-5.12). In 101 patients without post-treatment C1q-binding anti-HLA DSA there was a significantly improved glomerular filtration rate with significantly reduced glomerulitis, peritubular capillaritis, interstitial inflammation, tubulitis, C4d deposition, and endarteritis compared with 38 patients with posttreatment C1q-binding anti-HLA DSA. A conditional inference tree model identified five prognostic groups at the time of post-treatment evaluation based on glomerular filtration rate, presence of cg lesion and C1q-binding anti-HLA DSA (cross-validated accuracy: 0.77). Thus, circulating complement-binding anti-HLA DSAs are strong and independent predictors of allograft outcome after standard of care treatment in kidney recipients with ABMR.

​The Lung session of the 2017 14th Banff Foundation for Allograft Pathology Conference, Barcelona focused on the multiple aspects of antibody-mediated rejec-tion (AMR) in lung transplantation.

​Multidimensional approaches for AMR diagnosis, including classification, histological and immunohistochemical analysis, and donor- specific antibody (DSA) characterization with their current strengths and limitations were reviewed in view of recent research.

The group also discussed the role of tissue gene expression analysis in the context of unmet needs in lung transplantation. The current best practice for monitoring of AMR and the therapeutic approach are summarized and highlighted in this report.

The working group reached consensus of the major gaps in current knowledge and focused on the unanswered questions regard-ing pulmonary AMR. An important outcome of the meeting was agreement on the need for future collaborative research projects to address these gaps in the field of lung transplantation.

Abstract: 
No tool is available for the early assessment of response to antibody-mediated rejection (ABMR) therapies in kidney allograft recipients. This study was designed to define a dynamic composite prognostic ABMR score to predict kidney allograft survival, integrating the disease characteristics at diagnosis and the response to treatment. Among 1978 kidney recipients who underwent transplant between 2008 and 2014, we included 278 patients diagnosed with active ABMR and receiving standard treatment, including plasma exchange, intravenous Ig, and rituximab. Patients were prospectively assessed at diagnosis and after treatment for clinical data, histologic characteristics (allograft biopsy specimen), and donor-specific anti-HLA antibodies (DSA). The dynamic ABMR prediction model included GFR (P<0.001) and presence of interstitial fibrosis/tubular atrophy (P=0.003) at diagnosis and changes in GFR (P<0.001), peritubular capillaritis Banff score(P=0.002), and DSA mean fluorescence intensity (P<0.001) after treatment. Overall, this model showed good calibration and discrimination (C-statistic=0.84). The ABMR prognostic score derived from the prediction model identified three risk strata with 6-year kidney allograft survival rates of 6.0% (high-risk group, n=40), 44.9% (intermediate-risk group, n=36), and 84.4% (low-risk group, n=202), and it provided greater net clinical benefit to patients than did considering them all to have the same level of risk of allograft loss. The performance of the ABMR prognostic score was validated in an independent cohort of 202 kidney recipients with ABMR (C-statistic=0.79). The ABMR prognostic score could be used to inform therapeutic decisions in clinical practice and for the design of clinical trials.

​REVISED DIAGNOSTIC CRITERIA FOR CHRONIC ACTIVE T CELL–MEDIATED REJECTION, ANTIBODY‐MEDIATED REJECTION, AND PROSPECTS FOR INTEGRATIVE ENDPOINTS FOR NEXT‐GENERATION CLINICAL TRIALS

​The kidney sessions of the 2017 Banff Conference focused on 2 areas: clinical implications of inflammation in areas of interstitial fibrosis and tubular atrophy (i-IFTA) and its relationship to T cell-mediated rejection (TCMR), and the continued evolution of molecular diagnostics, particularly in the diagnosis of antibody-mediated rejection (ABMR). In confirmation of previous studies, it was independently demonstrated by 2 groups that i-IFTA is associated with reduced graft survival. Furthermore, these groups presented that i-IFTA, particularly when involving >25% of sclerotic cortex in association with tubulitis, is often a sequela of acute TCMR in association with underimmunosuppression. The classification was thus revised to include moderate i-IFTA plus moderate or severe tubulitis as diagnostic of chronic active TCMR. Other studies demonstrated that certain molecular classifiers improve diagnosis of ABMR beyond what is possible with histology, C4d, and detection of donor-specific antibodies (DSAs) and that both C4d and validated molecular assays can serve as potential alternatives and/or complements to DSAs in the diagnosis of ABMR. The Banff ABMR criteria are thus updated to include these alternatives. Finally, the present report paves the way for the Banff scheme to be part of an integrative approach for defining surrogate endpoints in next-generation clinical trials.

Abstract
Halloran PF, Potena L, Van Huyen JD, Bruneval P, Leone O, Kim DH, Jouven X, Reeve J, Loupy A.

The emergence of molecular systems offers opportunities for improving the assessment of rejection in heart transplant biopsy specimens. The present study developed a microarray-based system for assessing heart transplant endomyocardial biopsy (EMB) specimens.
We analyzed 331 protocol or for-cause EMB specimens from 221 subjects in 3 centers (Edmonton, Bologna, and Paris). Unsupervised principal component analysis (PCA) and archetype analysis used rejection-associated transcripts (RATs) shown in kidney transplants to be associated with antibody-mediated rejection (ABMR) or T cell-mediated rejection (TCMR), or both. To compare EMB specimens to kidney biopsy specimens, rejection status in both was simplified to TCMR, ABMR, or no rejection.
The pattern of RAT expression was similar in EMB and kidney specimens, permitting use of RATs to assign scores and group ("cluster") membership to each EMB, independent of histology. Three clusters emerged in EMB specimens, similar to kidney specimens: TCMR, ABMR, and no rejection. This permitted each EMB specimen to be given 3 scores and assigned to 1 cluster by its highest score. There was significant agreement between molecular phenotype-archetype scores or clusters-and both histologic diagnoses and donor-specific antibody. Area under curve estimates for predicting histologic TCMR, ABMR, and no rejection by molecular assessment were lower in EMB specimens than in kidney specimens, reflecting more uncertainty in EMB specimens, particularly in histologic diagnosis of TCMR.
Rejection-associated transcripts can be used to estimate the probability of TCMR and ABMR in heart transplant specimens, providing a new dimension to improve the accuracy of diagnoses and an independent system for recalibrating the histology guidelines.

1/ MOLECULAR CORRELATES OF ENDOTHELIAL MTOR ACTIVATION IN HEART TRANSPLANT RECIPIENTS
Session: “ Basic and translational immunology” (17:45 to 18:45)
Location: Room 118 + 119 – 18:29 

M Racapé, A Loupy, J Reeve, J Venner , R Guillemain, L Hidalgo, C Lefaucher, X Jouven, P Bruneval, J Duaong Van Huyen, P Halloran 
Background
The detection of phosphorylated effectors of the mTOR pathway such as phosphorylated-S6RP in endothelial cells by immunohistochemistry (IHC) has been associated with Antibody-Mediated allograft Rejection (AMR). The aim of this study was to evaluate the molecular phenotype related to the endothelial detection of pS6RP in heart transplant recipients.
Methods
This case-control study included 41 heart transplant patients from four French referral centers with biopsy proven antibody-mediated rejection (pAMR+) and a matched control group of 30 patients without rejection (pAMR0) based on the updated ISHLT classification. From these patients, 94 endomyocardial biopsies (EMB) had adequate material for microarray analysis and endothelial expression analysis of pS6RP by IHC. We also determined the allograft gene expression profile using the ABMR molecular score in addition to pathogenesis-based transcripts reflecting endothelial activation (DSAST and ENDAT), macrophage burden (QCMAT), gamma-interferon response (GRIT) and NK-cell burden (NKB) (http://atagc.med.ualberta.ca).
Results
Among the 94 EMBs included in the main analyses, 50 were pAMR+ (53.2%) and 44 (46.8%) were pAMR0 normal EMBs. Endothelial expression of pS6RP was observed in 27/50 (54%) of pAMR+ biopsies and 12 out of 44 normal biopsies (27.3%, Fischer's exact: p=0.012). As compared with biopsies without pS6RP labeling, biopsies with pS6RP staining showed increased expression of DSAST (Mann-Whitney: p<0.0001), ENDAT (p=0.0009), QCMAT (p=0.0046), NKB (p=0.0001), GRIT (p=0.0008) and increased ABMR molecular score reflecting AMR injury (p=0.0001).
Conclusion
Endothelial activation of mTOR pathway is associated with AMR and increased expression in transcripts reflecting endothelial activation, macrophage burden, microcirculation and NK burden. Our results suggest the importance of the mTOR pathway activation in AMR injury and the potential interest of using mTOR inhibitors in this setting.