Publications by authors named "Gillian Divard"

8 Publications

  • Page 1 of 1

Data-driven Derivation and Validation of Novel Phenotypes for Acute Kidney Transplant Rejection using Semi-supervised Clustering.

J Am Soc Nephrol 2021 May 9;32(5):1084-1096. Epub 2021 Mar 9.

Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium

Background: Over the past decades, an international group of experts iteratively developed a consensus classification of kidney transplant rejection phenotypes, known as the Banff classification. Data-driven clustering of kidney transplant histologic data could simplify the complex and discretionary rules of the Banff classification, while improving the association with graft failure.

Methods: The data consisted of a training set of 3510 kidney-transplant biopsies from an observational cohort of 936 recipients. Independent validation of the results was performed on an external set of 3835 biopsies from 1989 patients. On the basis of acute histologic lesion scores and the presence of donor-specific HLA antibodies, stable clustering was achieved on the basis of a consensus of 400 different clustering partitions. Additional information on kidney-transplant failure was introduced with a weighted Euclidean distance.

Results: Based on the proportion of ambiguous clustering, six clinically meaningful cluster phenotypes were identified. There was significant overlap with the existing Banff classification (adjusted rand index, 0.48). However, the data-driven approach eliminated intermediate and mixed phenotypes and created acute rejection clusters that are each significantly associated with graft failure. Finally, a novel visualization tool presents disease phenotypes and severity in a continuous manner, as a complement to the discrete clusters.

Conclusions: A semisupervised clustering approach for the identification of clinically meaningful novel phenotypes of kidney transplant rejection has been developed and validated. The approach has the potential to offer a more quantitative evaluation of rejection subtypes and severity, especially in situations in which the current histologic categorization is ambiguous.
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http://dx.doi.org/10.1681/ASN.2020101418DOI Listing
May 2021

Assessment of the Utility of Kidney Histology as a Basis for Discarding Organs in the United States: A Comparison of International Transplant Practices and Outcomes.

J Am Soc Nephrol 2021 Feb 15;32(2):397-409. Epub 2020 Dec 15.

Université de Paris, Institut National de la Santé et de la Recherche Médicale U970, Paris Translational Research Centre for Organ Transplantation, Paris, France

Background: Many kidneys donated for transplant in the United States are discarded because of abnormal histology. Whether histology adds incremental value beyond usual donor attributes in assessing allograft quality is unknown.

Methods: This population-based study included patients who received a deceased donor kidney that had been biopsied before implantation according to a prespecified protocol in France and Belgium, where preimplantation biopsy findings are generally not used for decision making in the allocation process. We also studied kidneys that had been acquired from deceased United States donors for transplantation that were biopsied during allocation and discarded because of low organ quality. Using donor and recipient characteristics, we fit multivariable Cox models for death-censored graft failure and examined whether predictive accuracy (C index) improved after adding donor histology. We matched the discarded United States kidneys to similar kidneys transplanted in Europe and calculated predicted allograft survival.

Results: In the development cohort of 1629 kidney recipients at two French centers, adding donor histology to the model did not significantly improve prediction of long-term allograft failure. Analyses using an external validation cohort from two Belgian centers confirmed the lack of improved accuracy from adding histology. About 45% of 1103 United States kidneys discarded because of histologic findings could be accurately matched to very similar kidneys that had been transplanted in France; these discarded kidneys would be expected to have allograft survival of 93.1% at 1 year, 80.7% at 5 years, and 68.9% at 10 years.

Conclusions: In this multicenter study, donor kidney histology assessment during allocation did not provide substantial incremental value in ascertaining organ quality. Many kidneys discarded on the basis of biopsy findings would likely benefit United States patients who are wait listed.
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http://dx.doi.org/10.1681/ASN.2020040464DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8054891PMC
February 2021

Increased incidence and unusual presentations of CMV disease in kidney transplant recipients after conversion to belatacept.

Am J Transplant 2020 Dec 6. Epub 2020 Dec 6.

Department of Nephrology and Kidney Transplantation, Necker Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France.

Belatacept may increase cytomegalovirus (CMV) disease risk after conversion from CNI-based therapy. We analyzed CMV disease characteristics after belatacept conversion. Propensity score matching was used to compare CMV disease incidence in belatacept- and CNI-treated kidney transplant recipients (KTRs). CMV disease characteristics and risk factors under belatacept were analyzed. In total, 223 KTRs (median age [IQR] 59.2 years [45.4-68.5]) were converted to belatacept (median of 11.5 months [2.5-37.0] post-transplantation); 40/223 (17.9%) developed CMV disease. Independent risk factors included increased age (p = .0164), D+/R- CMV serostatus (p = .0220), and low eGFR at conversion (p = .0355). Among 181 belatacept-treated patients matched to 181 controls, 32/181 (17.7%) experienced CMV disease (vs. 5/181 controls [2.8%]). CMV disease cumulative incidences were 6.33 and 0.91/100 person-years (p-y) in belatacept and control groups, respectively. CMV disease risk was particularly high in elderly patients (converted >70 years) and those with eGFR <30 ml/min; cumulative incidences were 18.4 and 5.2/100 p-y, respectively. CMV diseases under belatacept were atypical, with late-onset disease (24/40 patients [60%]), high CMV seropositivity (27/40, 67%), increased severe and tissue-invasive disease rates (gastrointestinal involvement in 32/40 [80%]) and life-threatening diseases (4/40 [10%]). These findings should stimulate further research to secure the use of belatacept as a valuable rescue therapy in KTRs.
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http://dx.doi.org/10.1111/ajt.16430DOI Listing
December 2020

Efficacy and Safety of Direct Oral Anticoagulants in Kidney Transplantation: A Single-center Pilot Experience.

Transplantation 2020 12;104(12):2625-2631

Service de Néphrologie et Transplantation Adulte, Hôpital Necker-Enfants Malades, Université Paris Descartes, Assistance Publique-Hôpitaux de Paris, Paris, France.

Background: Oral anticoagulation therapy is frequently prescribed to kidney transplant recipients (KTRs) for prevention and treatment of thrombotic events. Over the past 10 y, direct oral anticoagulants (DOACs) have shown similar efficacy with a safety profile equal or superior to that of vitamin K antagonist anticoagulants (VKAs) in the general population. However, little data are available on kidney transplantation.

Methods: We investigated the efficacy (thrombotic events) and safety (hemorrhagic and other adverse events and graft outcomes) of DOACs in a cohort of KTRs with a renal function >30 mL/min. We then compared these patients to a control group treated by VKA.

Results: Fifty-two KTRs treated by DOACs between 2013 and 2018 at Necker Hospital were included. Patients were with a mean age of 62 ± 13 y old and a mean glomerular filtration rate of 59 ± 20 mL/min/1.73m. The major indication was atrial fibrillation (n = 31 [60%]). Apixaban was the most commonly used agent (n = 36 [69%]). No thrombotic complications were reported under DOAC until last follow-up (14.1 ± 13 mo). In comparison to 50 controls under VKA during the same period, the bleeding rate under DOAC was significantly lower (11.5 versus 22.9 per 100 patient-y, P = 0.037) with a hazard ratio of 0.39 (95% confidence interval, 0.19-0.85, P = 0.041). No significant changes in kidney function, rejection rate, or hemoglobin level were reported.

Conclusions: DOACs appear to be effective and safe anticoagulants in KTRs with stable renal function.
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http://dx.doi.org/10.1097/TP.0000000000003168DOI Listing
December 2020

Prediction system for risk of allograft loss in patients receiving kidney transplants: international derivation and validation study.

BMJ 2019 09 17;366:l4923. Epub 2019 Sep 17.

Université de Paris, INSERM, Paris Translational Research Centre for Organ Transplantation, Paris, France.

Objective: To develop and validate an integrative system to predict long term kidney allograft failure.

Design: International cohort study.

Setting: Three cohorts including kidney transplant recipients from 10 academic medical centres from Europe and the United States.

Participants: Derivation cohort: 4000 consecutive kidney recipients prospectively recruited in four French centres between 2005 and 2014. Validation cohorts: 2129 kidney recipients from three centres in Europe and 1428 from three centres in North America, recruited between 2002 and 2014. Additional validation in three randomised controlled trials (NCT01079143, EudraCT 2007-003213-13, and NCT01873157).

Main Outcome Measure: Allograft failure (return to dialysis or pre-emptive retransplantation). 32 candidate prognostic factors for kidney allograft survival were assessed.

Results: Among the 7557 kidney transplant recipients included, 1067 (14.1%) allografts failed after a median post-transplant follow-up time of 7.12 (interquartile range 3.51-8.77) years. In the derivation cohort, eight functional, histological, and immunological prognostic factors were independently associated with allograft failure and were then combined into a risk prediction score (iBox). This score showed accurate calibration and discrimination (C index 0.81, 95% confidence interval 0.79 to 0.83). The performance of the iBox was also confirmed in the validation cohorts from Europe (C index 0.81, 0.78 to 0.84) and the US (0.80, 0.76 to 0.84). The iBox system showed accuracy when assessed at different times of evaluation post-transplant, was validated in different clinical scenarios including type of immunosuppressive regimen used and response to rejection therapy, and outperformed previous risk prediction scores as well as a risk score based solely on functional parameters including estimated glomerular filtration rate and proteinuria. Finally, the accuracy of the iBox risk score in predicting long term allograft loss was confirmed in the three randomised controlled trials.

Conclusion: An integrative, accurate, and readily implementable risk prediction score for kidney allograft failure has been developed, which shows generalisability across centres worldwide and common clinical scenarios. The iBox risk prediction score may help to guide monitoring of patients and further improve the design and development of a valid and early surrogate endpoint for clinical trials.

Trial Registration: Clinicaltrials.gov NCT03474003.
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http://dx.doi.org/10.1136/bmj.l4923DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6746192PMC
September 2019

Anti-IL-2R blockers comparing with polyclonal antibodies: Higher risk of rejection without negative mid-term outcomes after ABO-incompatible kidney transplantation.

Clin Transplant 2019 10 8;33(10):e13681. Epub 2019 Sep 8.

Department of Nephrology and Organ Transplant, CHU Rangueil, Toulouse, France.

There is no recommendation regarding the type of induction therapy to use in ABO-incompatible (ABOi) kidney transplantation. The aim of this retrospective study was to compare the outcome of ABOi living donor kidney transplant (LDKT) recipients who received either polyclonal antibodies or anti-interleukin-2 receptor (IL-2R) blockers as an induction agent. All ABOi HLA-compatible patients that received a LDKT between 03/11 and 03/18 in three French transplantation center (Paris Saint-Louis, Paris Necker, and Toulouse) were included in the study. Fifty-eight patients were given polyclonal antibodies and 39 patients received anti-IL-2R blockers. We identified by a Cox proportional hazard model the use of polyclonal antibodies as a protective factor against acute rejection (HR = 0.4, 95%CI [0-0.9], P < .05). However, pathological findings on protocol biopsies at 1 year were similar in both groups, as were patient and graft survivals, renal function, and complications. We conclude that the acute rejection rate was significantly higher in patients given anti-IL-2R blockers compared to polyclonal antibodies. However, in our series, there was no negative impact on mid-term outcome.
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http://dx.doi.org/10.1111/ctr.13681DOI Listing
October 2019

High-sensitivity cardiac troponin T is a biomarker for atherosclerosis in systemic lupus erythematous patients: a cross-sectional controlled study.

Arthritis Res Ther 2017 06 13;19(1):132. Epub 2017 Jun 13.

Département de Médecine Interne, Hôpital Bichat, Université Paris Diderot, PRES Sorbonne Paris Cité, Assistance Publique Hôpitaux de Paris, 46 rue Henri Huchard, 75018, Paris, France.

Background: Cardiovascular disease (CVD) is the main cause of death in systemic lupus erythematous (SLE) patients. The Framingham score underestimates the risk for CVD in this population. Our study aimed to determine whether serum high-sensitivity cardiac troponin T (HS-cTnT) might help to identify SLE patients at risk for CVD.

Methods: The presence of carotid plaques was prospectively assessed by ultrasound in 63 consecutive SLE patients asymptomatic for CVD and 18 controls. Serum HS-cTnT concentration was measured using the electrochemiluminescence method. Factors associated with carotid plaques were identified and multivariate analysis was performed.

Results: Framingham score was low in both SLE patients (median 1 (range 1-18%)) and controls (1 (1-13%)). Nevertheless, 23 (36.5%) SLE patients, but only 2 (11.1%) controls (p = 0.039), had carotid plaque detected by vascular ultrasound. In the multivariate analysis, only age (p = 0.006) and SLE status (p = 0.017) were independently associated with carotid plaques. Serum HS-cTnT concentration was detectable (i.e. >3 ng/L) in 37 (58.7%) SLE patients and 6 (33.3%) controls (p = 0.057). Interestingly, 87% of SLE patients with carotid plaques, but only 42.5% of SLE patients without plaques (p < 0.001), had detectable HS-cTnT. Conversely, 54.5% of SLE patients with detectable HS-cTnT, but only 11.5% with undetectable HS-cTnT (p < 0.001), had a carotid plaque. In the multivariate analysis, only body mass index (p = 0.006) and HS-cTnT (p = 0.033) were statistically associated with carotid plaques in SLE patients. Overall, the risk of having a carotid plaque was increased by 9 (odds ratio 9.26, 95% confidence interval 1.55-90.07) in SLE patients in whom HS-cTnT was detectable in serum.

Conclusion: Serum HS-cTnT level is high and associated with carotid plaques in SLE patients who are at an apparently low risk for CVD according to the Framingham score. HS-cTnT may be a useful biomarker for SLE-associated atherosclerosis.
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http://dx.doi.org/10.1186/s13075-017-1352-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5470230PMC
June 2017

Renal biopsies should be performed whenever treatment strategies depend on renal involvement.

Ann Rheum Dis 2017 08 25;76(8):e27. Epub 2017 Jan 25.

Department of Nephrology, Bichat-Claude Bernard Hospital, DHU Fire, AP-HP, Paris, France.

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http://dx.doi.org/10.1136/annrheumdis-2016-210933DOI Listing
August 2017