Clinico-biological refinement of BCL11B-related disorder and identification of an episignature: A series of 20 unreported individuals

PURPOSE

BCL11B-related disorder (BCL11B-RD) arises from rare genetic variants within the BCL11B gene, resulting in a distinctive clinical spectrum encompassing syndromic neurodevelopmental disorder, with or without intellectual disability, associated with facial features and impaired immune function. This study presents an in-depth clinico-biological analysis of 20 newly reported individuals with BCL11B-RD, coupled with a characterization of genome-wide DNA methylation patterns of this genetic condition.

METHODS

Through an international collaboration, clinical and molecular data from 20 individuals were systematically gathered, and a comparative analysis was conducted between this series and existing literature. We further scrutinized peripheral blood DNA methylation profile of individuals with BCL11B-RD, contrasting them with healthy controls and other neurodevelopmental disorders marked by established episignature.

RESULTS

Our findings unveil rarely documented clinical manifestations, notably including Rubinstein-Taybi-like facial features, craniosynostosis, and autoimmune disorders, all manifesting within the realm of BCL11B-RD. We refine the intricacies of T cell compartment alterations of BCL11B-RD, revealing decreased levels naive CD4+ T cells and recent thymic emigrants while concurrently observing an elevated proportion of effector-memory expressing CD45RA CD8+ T cells (TEMRA). Finally, a distinct DNA methylation episignature exclusive to BCL11B-RD is unveiled.

CONCLUSION

This study serves to enrich our comprehension of the clinico-biological landscape of BCL11B-RD, potentially furnishing a more precise framework for diagnosis and follow-up of individuals carrying pathogenic BCL11B variant. Moreover, the identification of a unique DNA methylation episignature offers a valuable diagnosis tool for BCL11B-RD, thereby facilitating routine clinical practice by empowering physicians to reevaluate variants of uncertain significance within the BCL11B gene.

Race-free estimated glomerular filtration rate equation in kidney transplant recipients: development and validation study

OBJECTIVE

To compare the performance of a newly developed race-free kidney recipient specific glomerular filtration rate (GFR) equation with the three current main equations for measuring GFR in kidney transplant recipients.

DESIGN

Development and validation study SETTING: 17 cohorts in Europe, the United States, and Australia (14 transplant centres, three clinical trials).

PARTICIPANTS

15 489 adults (3622 in development cohort (Necker, Saint Louis, and Toulouse hospitals, France), 11 867 in multiple external validation cohorts) who received kidney transplants between 1 January 2000 and 1 January 2021.

MAIN OUTCOME MEASURE

The main outcome measure was GFR, measured according to local practice. Performance of the GFR equations was assessed using P30 (proportion of estimated GFR (eGFR) within 30% of measured GFR (mGFR)) and correct classification (agreement between eGFR and mGFR according to GFR stages). The race-free equation, based on creatinine level, age, and sex, was developed using additive and multiplicative linear regressions, and its performance was compared with the three current main GFR equations: Modification of Diet in Renal Disease (MDRD) equation, Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) 2009 equation, and race-free CKD-EPI 2021 equation.

RESULTS

The study included 15 489 participants, with 50 464 mGFR and eGFR values. The mean GFR was 53.18 mL/min/1.73m2 (SD 17.23) in the development cohort and 55.90 mL/min/1.73m2 (19.69) in the external validation cohorts. Among the current GFR equations, the race-free CKD-EPI 2021 equation showed the lowest performance compared with the MDRD and CKD-EPI 2009 equations. When race was included in the kidney recipient specific GFR equation, performance did not increase. The race-free kidney recipient specific GFR equation showed significantly improved performance compared with the race-free CKD-EPI 2021 equation and performed well in the external validation cohorts (P30 ranging from 73.0% to 91.3%). The race-free kidney recipient specific GFR equation performed well in several subpopulations of kidney transplant recipients stratified by race (P30 73.0-91.3%), sex (72.7-91.4%), age (70.3-92.0%), body mass index (64.5-100%), donor type (58.5-92.9%), donor age (68.3-94.3%), treatment (78.5-85.2%), creatinine level (72.8-91.3%), GFR measurement method (73.0-91.3%), and timing of GFR measurement post-transplant (72.9-95.5%). An online application was developed that estimates GFR based on recipient's creatinine level, age, and sex (https://transplant-prediction-system.shinyapps.io/eGFR_equation_KTX/).

CONCLUSION

A new race-free kidney recipient specific GFR equation was developed and validated using multiple, large, international cohorts of kidney transplant recipients. The equation showed high accuracy and outperformed the race-free CKD-EPI 2021 equation that was developed in individuals with native kidneys.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05229939.

Nonskeletal and skeletal effects of high doses versus low doses of vitamin D3 in renal transplant recipients: Results of the VITALE (VITamin D supplementation in renAL transplant recipients) study, a randomized clinical trial

Vitamin D sufficiency is associated with a reduced risk of fractures, diabetes mellitus, cardiovascular events, and cancers, which are frequent complications after renal transplantation. The VITALE (VITamin D supplementation in renAL transplant recipients) study is a multicenter double-blind randomized trial, including nondiabetic adult renal transplant recipients with serum 25-hydroxy vitamin D (25(OH) vitamin D) levels of <30 ng/mL, which is randomized 12 to 48 months after transplantation to receive high (100 000 IU) or low doses (12 000 IU) of cholecalciferol every 2 weeks for 2 months and then monthly for 22 months. The primary outcome was a composite endpoint, including diabetes mellitus, major cardiovascular events, cancer, and death. Of 536 inclusions (50.8 [13.7] years, 335 men), 269 and 267 inclusions were in the high-dose and low-dose groups, respectively. The serum 25(OH) vitamin D levels increased by 23 versus 6 ng/mL in the high-dose and low-dose groups, respectively (P < .0001). In the intent-to-treat analysis, 15% versus 16% of the patients in the high-dose and low-dose groups, respectively, experienced a first event of the composite endpoint (hazard ratio, 0.94 [0.60-1.48]; P = .78), whereas 1% and 4% of patients in the high-dose and low-dose groups, respectively, experienced an incident symptomatic fracture (odds ratio, 0.24 [0.07-0.86], P = .03). The incidence of adverse events was similar between the groups. After renal transplantation, high doses of cholecalciferol are safe but do not reduce extraskeletal complications (trial registration: ClinicalTrials.gov; identifier: NCT01431430).

C5b-9 Glomerular Deposits Are Associated With Poor Renal Survival in Membranous Nephropathy

Introduction

Membranous nephropathy (MN) is the first cause of nephrotic syndrome in patients without diabetes. Its prognosis is variable, and treatment remains controversial because of potential toxicity. Currently, there is no reliable prognostic marker common to all etiologies of MN and routinely available to predict the disease course and guide therapeutic management. Despite the major role of complement in the glomerular damage of MN, its prognostic impact has never been studied. We investigated the frequency and prognostic impact of glomerular deposition of C5b-9 in MN.

Methods

We retrospectively selected adults diagnosed with MN (primary or secondary) at Montpellier University Hospital between December 2004 and December 2015. To be included, all patients were required to have complete medical data and a kidney tissue sample for further immunohistochemistry. We performed PLA2R1, C4d, and C5b-9 staining by immunohistochemistry.

Results

Sixty-four adults were included: 45 with primary MN and 19 with secondary MN. C4d was positive in the glomeruli of 61 adults (95.3%). Twenty-nine adults (45.3%) had glomerular deposition of C5b-9. Patients with glomerular deposition of C5b-9 had more severe nephrotic syndrome on diagnosis and lower remission and renal survival rates than adults without.

Conclusion

C5b-9 glomerular staining is a powerful and easily accessible tool for stratifying adults according to their renal prognosis. The efficacy of complement inhibitors should be tested in adults with glomerular deposition of C5b-9.

Impaired antigen-specific B-cell responses after Influenza vaccination in kidney transplant recipients receiving co-stimulation blockade with Belatacept

Emerging data suggest that costimulation blockade with belatacept effectively controls humoral alloimmune responses. However, whether this effect may be deleterious for protective anti-infectious immunity remains poorly understood. We performed a mechanistic exploratory study in 23 kidney transplant recipients receiving either the calcineurin-inhibitor tacrolimus (Tac, n=14) or belatacept (n=9) evaluating different cellular immune responses after influenza vaccination such as activated T follicular Helper (Tfh), plasmablasts and H1N1 hemagglutinin (HA)-specific memory B cells (HA⁺mBC) by flow-cytometry, and anti-influenza antibodies by hemagglutination inhibition test (HI), at baseline and days 10, 30 and 90 post-vaccination. The proportion of CD4+CD54RA-CXCR5+ Tfh was lower in belatacept than Tac patients at baseline (1.86%[1.25-3.03] vs 4.88%[2.40-8.27], p=0.01) and remained stable post-vaccination. At M3, HA⁺mBc were significantly higher in Tac-treated patients (0.56%[0.32-1.49] vs 0.27%[0.13-0.44], p=0.04) and correlated with activated Tfh numbers. When stratifying patients according to baseline HA⁺mBc frequencies, belatacept patients with low HA⁺mBC displayed significantly lower HA⁺mBc increases after vaccination than Tac patients (1.28[0.94-2.4] vs 2.54[1.73-5.70], p=0.04). Also, belatacept patients displayed significantly lower seroprotection rates against H1N1 at baseline than Tac-treated patients (44.4% vs 84.6%) as well as lower seroconversion rates at days 10, 30 and 90 after vaccination (50% vs 0%, 63.6% vs 0%, and 63.6% vs 0%, respectively). We show the efficacy of belatacept inhibiting T-dependent antigen-specific humoral immune responses, active immunization should be highly encouraged before starting belatacept therapy.

The MHC class I MICA gene is a histocompatibility antigen in kidney transplantation

The identity of histocompatibility loci, besides human leukocyte antigen (HLA), remains elusive. The major histocompatibility complex (MHC) class I MICA gene is a candidate histocompatibility locus. Here, we investigate its role in a French multicenter cohort of 1,356 kidney transplants. MICA mismatches were associated with decreased graft survival (hazard ratio (HR), 2.12; 95% confidence interval (CI): 1.45–3.11; P < 0.001). Both before and after transplantation anti-MICA donor-specific antibodies (DSA) were strongly associated with increased antibody-mediated rejection (ABMR) (HR, 3.79; 95% CI: 1.94–7.39; P < 0.001; HR, 9.92; 95% CI: 7.43–13.20; P < 0.001, respectively). This effect was synergetic with that of anti-HLA DSA before and after transplantation (HR, 25.68; 95% CI: 3.31–199.41; P = 0.002; HR, 82.67; 95% CI: 33.67–202.97; P < 0.001, respectively). De novo-developed anti-MICA DSA were the most harmful because they were also associated with reduced graft survival (HR, 1.29; 95% CI: 1.05–1.58; P = 0.014). Finally, the damaging effect of anti-MICA DSA on graft survival was confirmed in an independent cohort of 168 patients with ABMR (HR, 1.71; 95% CI: 1.02–2.86; P = 0.041). In conclusion, assessment of MICA matching and immunization for the identification of patients at high risk for transplant rejection and loss is warranted.

Analysis of a multicenter cohort of kidney transplants shows that mismatches in the MICA locus and the presence of anti-MICA donor-specific antibodies are associated with reduced graft survival and increased rejection.

IgG3 donor-specific antibodies with a proinflammatory glycosylation profile may be associated with the risk of antibody-mediated rejection after kidney transplantation

The pathogenicity of de novo donor-specific antibodies (dnDSA) varies according to their characteristics. While their MFI, complement-fixing ability, and IgG3 subclass are associated with ABMR occurrence and graft loss, they are not fully predictive of outcomes. We investigated the role of the Fc glycosylation of IgG3 dnDSA in ABMR occurrence using mass spectrometry after isolation by single HLA antigen beads. Between 2014 and 2018, we enrolled 54 patients who developed dnDSA (ABMR- n = 24; ABMR+ n = 30) in two French transplant centers. Fucosylation, galactosylation, GlcNAc bisection, and sialylation of IgG3 dnDSA were compared between ABMR+ and ABMR- patients. IgG3 dnDSA from ABMR+ patients exhibited significantly lower sialylation (7.5% vs. 10.5%, p < .001) and higher GlcNAc bisection (20.6% vs. 17.4%, p = .008). Fucosylation and galactosylation were similar in both groups. DSA glycosylation was not correlated with DSA MFI. In a multivariate analysis, low IgG3 sialylation, high IgG3%, time from transplantation to kidney biopsy, and tacrolimus-free regimen were independent predictive factors of ABMR. We conclude that a proinflammatory glycosylation profile of IgG3 dnDSA is associated with a risk of ABMR occurrence. Further studies are needed to confirm the clinical interest of DSA glycosylation and to clarify its role in determining the risk of ABMR and graft survival.

Contactin-1 is a novel target antigen in membranous nephropathy associated with chronic inflammatory demyelinating polyneuropathy

Primary membranous nephropathy (MN) is an autoimmune glomerular disease in which autoantibodies are directed against podocyte proteins. In about 80% of cases the main targeted antigen is the phospholipase A2 receptor 1 (PLA2R1). Anti-PLA2R1 antibodies are mainly immunoglobulin G type 4 (IgG4). However, the antigenic target remains to be defined in 20% of cases. MN can be associated with chronic inflammatory demyelinating polyneuropathy, an autoimmune disease of the peripheral nervous system where a common antigenic target has yet to be identified. To ascertain a possible novel target antigen, we analyzed kidney biopsies from five patients positive for anti-contactin 1 antibodies and presenting with MN combined with chronic inflammatory demyelinating polyneuropathy. Eluted IgG from biopsy sections against contactin 1 and nerve tissue were screened. Western blot revealed contactin 1 expression in normal kidney glomeruli. Confocal microscopic analysis showed the presence and colocalization of contactin 1 and IgG4 on the glomerular basement membrane of these patients. Glomerular contactin 1 was absent in patients with anti-PLA2R1-associated MN or membranous lupus nephritis or a healthy control. The eluted IgG from contactin 1-positive biopsy sections but not the IgG eluted from patients with PLA2R1 MN bound contactin 1 with the main eluted subclass IgG4. Eluted IgG could bind paranodal tissue (myelinated axon) and colocalized with commercial anti-contactin 1 antibody. Thus, contactin 1 is a novel common antigenic target in MN associated with chronic inflammatory demyelinating polyneuropathy. However, the precise pathophysiology remains to be elucidated.

Rituximab for recurrence of primary focal segmental glomerulosclerosis after kidney transplantation: Results of a nationwide study

Rituximab (RTX) therapy for primary focal segmental glomerulosclerosis recurrence after kidney transplantation (KT) has been extensively debated. We aimed to assess the benefit of adding RTX to plasmapheresis (PP), corticosteroids, and calcineurin inhibitors (standard of care, SOC). We identified 148 adult patients who received KT in 12/2004-12/2018 at 21 French centers: 109 received SOC (Group 1, G1), and 39 received immediate RTX along with SOC (Group 2, G2). In G1, RTX was introduced after 28 days of SOC in the event of failure (G1a, n = 19) or PP withdrawal (G1b, n = 12). Complete remission (CR) was achieved in 46.6% of patients, and partial remission (PR) was achieved in 33.1%. The 10-year graft survival rates were 64.7% and 17.9% in responders and nonresponders, respectively. Propensity score analysis showed no difference in CR+PR rates between G1 (82.6%) and G2 (71.8%) (p = .08). Following the addition of RTX (G1a), 26.3% of patients had CR, and 31.6% had PR. The incidence of severe infections was similar between patients treated with and without RTX. In multivariable analysis, infection episodes were associated with hypogammaglobulinemia <5 g/L. RTX could be used in cases of SOC failure or remission for early discontinuation of PP without increasing the risk of infection.

Cohort study: "Outcomes of kidney transplantation in patients with prosthetic heart valves"

The number of kidney transplant candidates with prosthetic heart valves (PHVs) is increasing. Yet, outcomes of kidney transplantation in these patients are still unclear. This is the first report of post-transplant outcomes in patients with PHVs at time of kidney transplantation. We conducted a matched cohort study among recipients from the multicentric and prospective DIVAT cohort to compare the outcomes in patients with left-sided PHVs at time of transplantation and a group of recipients without PHV matched according to age, dialysis time, initial disease, pretransplant DSA, diabetes, and cardiovascular events. Of 23 018 patients, 92 patients with PHVs were included and compared to 276 patients without PHV. Delayed graft function and postoperative bleeding occurred more frequently in patients with PHVs. Kidney graft survival was similar between groups. 5-year overall survival was 68.5% in patients with PHV vs. 87.9% in patients without PHV [HR, 2.72 (1.57-4.70), P = 0.0004]. Deaths from infection, endocarditis, and bleeding were more frequent in patients with PHV. Mechanical valves, but not bioprosthetic valves, were independent risk factors for mortality [HR, 2.89 (1.68-4.97), P = 0.0001]. Patients with PHV have high mortality rates after kidney transplantation. These data suggest that mechanical valves, but not biological valves, increase risks of post-transplant mortality.

SARS-CoV-2-specific serological and functional T cell immune responses during acute and early COVID-19 convalescence in solid organ transplant patients

The description of protective humoral and T cell immune responses specific against SARS-CoV-2 has been reported among immunocompetent (IC) individuals developing COVID-19 infection. However, its characterization and determinants of poorer outcomes among the at-risk solid organ transplant (SOT) patient population have not been thoroughly investigated. Cytokine-producing T cell responses, such as IFN-γ, IL-2, IFN-γ/IL-2, IL-6, IL-21, and IL-5, against main immunogenic SARS-CoV-2 antigens and IgM/IgG serological immunity were tracked in SOT (n = 28) during acute infection and at two consecutive time points over the following 40 days of convalescence and were compared to matched IC (n = 16) patients admitted with similar moderate/severe COVID-19. We describe the development of a robust serological and functional T cell immune responses against SARS-CoV-2 among SOT patients, similar to IC patients during early convalescence. However, at the infection onset, SOT displayed lower IgG seroconversion rates (77% vs. 100%; p = .044), despite no differences on IgG titers, and a trend toward decreased SARS-CoV-2-reactive T cell frequencies, especially against the membrane protein (7 [0-34] vs. 113 [15-245], p = .011, 2 [0-9] vs. 45 [5-74], p = .009, and 0 [0-2] vs. 13 [1-24], p = .020, IFN-γ, IL-2, and IFN-γ/IL-2 spots, respectively). In summary, our data suggest that despite a certain initial delay, SOT population achieve comparable functional immune responses than the general population after moderate/severe COVID-19.

Kidney transplantation from expanded criteria donors: an increased risk of urinary complications - the UriNary Complications Of Renal Transplant (UNyCORT) study

OBJECTIVES

To assess the impact of expanded criteria donors (ECD) on urinary complications in kidney transplantation.

PATIENTS AND METHODS

The UriNary Complications Of Renal Transplant (UNyCORT) is a cohort study based on the French prospective Données Informatisées et VAlidées en Transplantation/Computerized and VAlidated Data in Transplantation (DIVAT) cohort. Data were extracted between 1 January 2002 and 1 January 2018 with 1-year minimum follow-up, in relation to 44 pre- and postoperative variables. ECD status was included according to United Network for Organ Sharing (UNOS) definition. The primary outcome of the UNyCORT study was the association between the donor's ECD/standard criteria donors (SCD) status and urinary complications at 1 year in uni- and multivariate analysis. Sub-group analysis, stratified analysis on ECD/SCD donor's status and transplant failure analysis were then conducted.

RESULTS

Between 1 January 2002 and 1 January 2018, 10 279 kidney transplants in adult recipients were recorded within the DIVAT network. A total of 8559 (83.4%) donors were deceased donors and 1699 (16.6%) were living donors (LD). Among donation after circulatory death (DCD) donors, 224 (2.85%) were uncontrolled DCD and 93 (1.09%) were controlled DCD donors. A total of 3617 (43.9%) deceased donors were ECD. The overall urological complication rate was 16.26%. The donor's ECD status was significantly associated with an increased risk of urological complications at 1 year in multivariate analysis (odds ratio: 1.50, 95% CI 1.31-1.71; P < 0.001) and especially with stenosis and ureteric fistulae at 1 year. There is no association with LD, uncontrolled and controlled DCD. The placement of an endo-ureteric stent was beneficial in preventing urinary complications in all donors and particularly in ECD donors.

CONCLUSION

The donor's ECD status is associated with a higher likelihood of stenosis and ureteric fistulae at 1 year. Recipients of grafts from ECD donors should probably be considered for closer urological monitoring and systematic preventive measures.

Donor/Recipient HLA Molecular Mismatch Scores Predict Primary Humoral and Cellular Alloimmunity in Kidney Transplantation

Donor/recipient molecular human leukocyte antigen (HLA) mismatch predicts primary B-cell alloimmune activation, yet the impact on de novo donor-specific T-cell alloimmunity (dnDST) remains undetermined. The hypothesis of our study is that donor/recipient HLA mismatches assessed at the molecular level may also influence a higher susceptibility to the development of posttransplant primary T-cell alloimmunity. In this prospective observational study, 169 consecutive kidney transplant recipients without preformed donor-specific antibodies (DSA) and with high resolution donor/recipient HLA typing were evaluated for HLA molecular mismatch scores using different informatic algorithms [amino acid mismatch, eplet MM, and Predicted Indirectly Recognizable HLA Epitopes (PIRCHE-II)]. Primary donor-specific alloimmune activation over the first 2 years posttransplantation was assessed by means of both dnDSA and dnDST using single antigen bead (SAB) and IFN-γ ELISPOT assays, respectively. Also, the predominant alloantigen presenting pathway priming DST alloimmunity and the contribution of main alloreactive T-cell subsets were further characterized in vitro. Pretransplantation, 78/169 (46%) were DST+ whereas 91/169 (54%) DST−. At 2 years, 54/169 (32%) patients showed detectable DST responses: 23/54 (42%) dnDST and 31/54 (57%) persistently positive (persistDST+). 24/169 (14%) patients developed dnDSA. A strong correlation was observed between the three distinct molecular mismatch scores and they all accurately predicted dnDSA formation, in particular at the DQ locus. Likewise, HLA molecular incompatibility predicted the advent of dnDST, especially when assessed by PIRCHE-II score (OR 1.014 95% CI 1.001–1.03, p=0.04). While pretransplant DST predicted the development of posttransplant BPAR (OR 5.18, 95% CI=1.64–16.34, p=0.005) and particularly T cell mediated rejection (OR 5.33, 95% CI=1.45–19.66, p=0.012), patients developing dnDST were at significantly higher risk of subsequent dnDSA formation (HR 2.64, 95% CI=1.08–6.45, p=0.03). In vitro experiments showed that unlike preformed DST that is predominantly primed by CD8+ direct pathway T cells, posttransplant DST may also be activated by the indirect pathway of alloantigen presentation, and predominantly driven by CD4+ alloreactive T cells in an important proportion of patients. De novo donor-specific cellular alloreactivity seems to precede subsequent humoral alloimmune activation and is influenced by a poor donor/recipient HLA molecular matching.

Renal transplantation outcomes in obese patients: a French cohort-based study

Background

Whilst there are a number of publications comparing the relationship between body mass index (BMI) of kidney transplant recipients and graft/patient survival, no study has assessed this for a French patient cohort.

Methods

In this study, cause-specific Cox models were used to study patient and graft survival and several other time-to-event measures. Logistic regressions were performed to study surgical complications at 30 days post-transplantation as well as delayed graft function.

Results

Among the 4691 included patients, 747 patients were considered obese with a BMI level greater than 30 kg/m². We observed a higher mortality for obese recipients (HR = 1.37, p = 0.0086) and higher risks of serious bacterial infections (HR = 1.24, p = 0.0006) and cardiac complications (HR = 1.45, p < 0.0001). We observed a trend towards death censored graft survival (HR = 1.22, p = 0.0666) and no significant increased risk of early surgical complications.

Conclusions

We showed that obesity increased the risk of death and serious bacterial infections and cardiac complications in obese French kidney transplant recipients. Further epidemiologic studies aiming to compare obese recipients versus obese candidates remaining on dialysis are needed to improve the guidelines for obese patient transplant allocation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12882-021-02278-1.

Induction therapy in kidney transplant recipients: Description of the practices according to the calendar period from the French multicentric DIVAT cohort

Background

There is extensive literature with comparisons between Anti-Thymocyte Globulin (ATG) and Basiliximab (BSX) as induction therapy in kidney transplant recipients. The purpose of our benchmarking study was to describe the consequences in terms of practices in 6 transplantation centers of a French prospective cohort.

Methods

We included adult patients who received a first or second kidney graft between 2013 and 2019 (n = 4157). We used logistic regressions to identify characteristics associated with the use of ATG or BSX.

Results

Use of ATG between the centers ranged from 41% to 75%. We observed different factors associated with the treatment decision. Compared to a first transplant, performing a second graft was the only factor significantly associated with the choice of ATG in all centers. The AUC ranged from 0.67 to 0.91, indicating that the centers seemed to define their own rules. As a result, for patients with the same low immunological risk, the probability of receiving ATG varied from 7% to 36%. We stratified the analyses according to two periods, from 2013 to 2015 and from 2016 to 2019. A similar heterogeneity was observed, and in some cases ATG indications between the centers were inverted.

Conclusions

The heterogeneity of induction therapy practices did not decrease in France, even if the reated literature is prolific. This illustrates the necessity to improve the literature by using meta-analyses of recent studies stratified by graft and patient profiles.

A Randomized Prospective Study Comparing Anti-T-Lymphocyte Igs to Basiliximab in Highly Sensitized Kidney Transplant Patients

Background

Two prospective studies that were performed before the era of highly sensitive solid-phase assays have shown a lower incidence of acute rejection in highly sensitized kidney-transplant patients given polyclonal antibodies compared with those given anti-CD25 monoclonal antibodies.

Methods

This prospective pilot randomized French multicenter study aimed to compare anti–T-lymphocyte Ig (ATLG) (n = 32) and basiliximab (n = 27) in highly sensitized kidney-transplant patients without preformed donor-specific antibodies (pDSAs) as assessed by a Luminex Single-Antigen flow bead assay. Only patients with a calculated panel reactive antibody ≥50%, with at least 1 antibody with a mean fluorescence intensity ≥5000 and without a historical pDSA and without a pDSA on the day of transplantation were included.

Results

Treatment failure as defined by biopsy-proven acute rejection, patient lost to follow-up, graft loss, and death was observed in 18.8% (95% confidence interval [CI], 8.9%–37.1%) and 18.8% (95% CI, 8.9%–37.1%) in patients who received ATLG and 14.8% (95% CI, 5.8%–34.8%) and 28.2% (95% CI, 14.2%–51.2%) of patients who received basiliximab, respectively at 6 (P = 0.66) and 12 (P = 0.62) months post-transplantation. One T cell–mediated rejection was observed in ATLG-treated patients (3.1%). One antibody-mediated rejection due to a de novo donor-specific antibody (DSA) occurred in basiliximab-treated patients (3.7%). Patient survival, graft survival, kidney parameters, and infection rate were similar in the 2 groups.

Conclusion

This pilot study indicates that in highly sensitized kidney-transplant patients without pDSAs, both ATLG and basiliximab can be used efficiently and safely. However, because of the lack of power, these results should be interpreted with caution.

Distribution of de novo Donor-Specific Antibody Subclasses Quantified by Mass Spectrometry: High IgG3 Proportion Is Associated With Antibody-Mediated Rejection Occurrence and Severity

Donor-specific antibodies (DSAs) are the main risk factor for antibody-mediated rejection (ABMR) and graft loss but could have variable pathogenicity according to their IgG subclass composition. Luminex-based test might lack sensitivity for the detection of IgG subclasses and this test does not allow quantifying the relative abundance of each IgG subclass. We investigated the precise repartition of each DSA subclass and their role in ABMR occurrence and severity, using an innovative mass spectrometry-based method. Between 2014 and 2018, we enrolled 69 patients who developed de novo DSA (n = 29 without ABMR, and n = 40 with ABMR) in two transplant centers. All IgG subclasses were detected in every samples tested: 62.7% were IgG1, 26.6% were IgG2, 6.6% were IgG3, and 4.2% were IgG4. The IgG3 proportion was significantly higher in the ABMR+ compared to the ABMR– group (8.4% vs. 5.6%, p = 0.003). The proportion of IgG1, IgG2, and IgG4 of DSA was similar between the two groups. Higher IgG3 level was associated with higher C4d deposition, higher microvascular inflammation scores, and glomerular filtration rate decline >25%. IgG3 proportion was not correlated with DSA MFI. Multivariate analysis showed that proteinuria and high level of IgG3 DSA were the only two factors independently associated with ABMR. In conclusion, de novo DSA are always composed of the four IgG subclasses, but in different proportions. High IgG3 proportion is associated with ABMR occurrence and severity and with poorer outcome, independently of DSA MFI.

P1757RITUXIMAB FOR RECURRENCE OF PRIMARY FOCAL SEGMENTAL GLOMERULOSCLEROSIS AFTER KIDNEY TRANSPLANTATION: RESULTS OF A NATIONWIDE STUDY

Background and Aims

The indication of rituximab (RTX) in the treatment of primary focal segmental glomerulosclerosis (FSGS) recurrence after kidney transplantation (KT) remains controversial. The objective of our study was to evaluate the benefit and tolerability of adding RTX to the standard of care (SOC) comprising plasmapheresis (PP), corticosteroids, and high-dose anticalcineurins for the treatment of FSGS recurrence after KT.

Method

This retrospective, multicenter study reports on 148 patients, transplanted between 31 December 2004 and 31 December 2018, aged 39.9 + 13.4 years, who developed FSGS recurrence at 7 [3–23] days. In all 109 patients received a SOC (Group 1). RTX was introduced in this group after more than 28 days of SOC for failure or for therapeutic intensification (n = 19, Group 1a), or for early discontinuation of PP (n = 12, Group 1b); 39 patients received RTX associated at the outset with SOC (Group 2).

Results

We observed 46.6% complete remission (CR) and 33.1% partial remission (PR). Ten-year graft survival was 65.6% [51.4–76.6] and 13.4% [3.4–30.0] in responders and non-responders respectively. There was no difference in CR + PR rate between G1 (82.5%) and G2 (71.8%), p = 0.08, confirmed by propensity score +4.3% (95% CI [−9.0%-17.5%], p = 0.53). Following addition of RTX (Group 1a), we observed a CR rate of 26.3% and a PR rate of 31.6%. Patients with and without RTX experienced similar rejection rates (18.6% and 28.2%, p = 0.17) and infection rates (71.4% and 79.5%, p = 0.40). In multivariate analysis, the infections were associted with hypogammaglobulinemia &lt;5g/l (OR = 8.04, 95% CI [1.65,39.25], p = 0.01).

Conclusion

Rituximab could be used in cases of SOC failure or in remission patients for early weaning of plasmapheresis, without increasing infectious risk.

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Background

The increased survival of patients with multiple myeloma (MM) raises the question of kidney transplantation (KT) in patients with end-stage renal disease (ESRD).

Methods

We included 13 patients with MM or smoldering myeloma (SMM) and ESRD transplanted between 2007 and 2015, including 7 MM with cast nephropathy, 3 with MM-associated amyloid light chain amyloidosis or light chain deposition disease and 3 SMM and compared them with 65 control-matched kidney-transplanted patients. Nine of the MM patients with KT were also compared with 63 matched MM patients on haemodialysis.

Results

Pre-transplantation parameters were comparable, except for the duration of renal replacement therapy (57.8 versus 37.0 months; P = 0.029) in MM versus control patients, respectively. The median follow-up post-KT was 44.4 versus 36.4 months (P = 0.40). The median MM graft and patient survival were 80.1 and 117.2 months, respectively, and were not significantly different from control patients, although mortality tended to be higher in the 10 symptomatic MM patients (P = 0.059). MM patients had significantly more viral and fungal infections and immunosuppressive maintenance therapy modifications while they received lower induction therapy. Two MM patients relapsed and two SMM cases evolved to MM after KT. Three cast nephropathies occurred, two of them leading to ESRD. Moreover, survival of MM with KT increased relative to control haemodialysed patients (P = 0.002).

Conclusions

Selected MM patients may benefit from KT but need careful surveillance in the case of KT complications and MM evolution.

Dynamic predictions of long-term kidney graft failure: an information tool promoting patient-centred care

Background

Informing kidney transplant recipients of their prognosis and disease progression is of primary importance in a patient-centred vision of care. By participating in decisions from the outset, transplant recipients may be more adherent to complex medical regimens due to their enhanced understanding.

Methods

We proposed to include repeated measurements of serum creatinine (SCr), in addition to baseline characteristics, in order to obtain dynamic predictions of the graft failure risk that could be updated continuously during patient follow-up. Adult recipients from the French Données Informatisées et VAlidées en Transplantation (DIVAT) cohort transplanted for the first or second time from a heart-beating or living donor and alive with a functioning graft at 1 year post-transplantation were included.

Results

The model was composed of six baseline parameters, in addition to the SCr evolution. We validated the dynamic predictions by evaluating both discrimination and calibration accuracy. The area under the receiver operating characteristic curve varied from 0.72 to 0.76 for prediction times at 1 and 6 years post-transplantation, respectively, while calibration plots showed correct accuracy. We also provided an online application tool (https://shiny.idbc.fr/DynPG).

Conclusion

We have created a tool that, for the first time in kidney transplantation, predicts graft failure risk both at an individual patient level and dynamically. We believe that this tool would encourage willing patients into participative medicine.

C5b9 Deposition in Glomerular Capillaries Is Associated With Poor Kidney Allograft Survival in Antibody-Mediated Rejection

C4d deposition in peritubular capillaries (PTC) reflects complement activation in antibody-mediated rejection (ABMR) of kidney allograft. However, its association with allograft survival is controversial. We hypothesized that capillary deposition of C5b9-indicative of complement-mediated injury-is a severity marker of ABMR. This pilot study aimed to determine the frequency, location and prognostic impact of these deposits in ABMR. We retrospectively selected patients diagnosed with ABMR in two French transplantation centers from January 2005 to December 2014 and performed C4d and C5b9 staining by immunohistochemistry. Fifty-four patients were included. Median follow-up was 52.5 (34.25-73.5) months. Thirteen patients (24%) had C5b9 deposits along glomerular capillaries (GC). Among these, seven (54%) had a global and diffuse staining pattern. Twelve of the C5b9+ patients also had deposition of C4d in GC and PTC. C4d deposits along GC and PTC were not associated with death-censored allograft survival (p = 0.42 and 0.69, respectively). However, death-censored allograft survival was significantly lower in patients with global and diffuse deposition of C5b9 in GC than those with a segmental pattern or no deposition (median survival after ABMR diagnosis, 6 months, 40.5 months and 44 months, respectively; p = 0.015). Double contour of glomerular basement membrane was diagnosed earlier after transplantation in C5b9+ ABMR than in C5b9- ABMR (median time after transplantation, 28 vs. 85 months; p = 0.058). In conclusion, we identified a new pattern of C5b9+ ABMR, associated with early onset of glomerular basement membrane duplication and poor allograft survival. Complement inhibitors might be a therapeutic option for this subgroup of patients.

Endothelium structure and function in kidney health and disease

The kidney harbours different types of endothelia, each with specific structural and functional characteristics. The glomerular endothelium, which is highly fenestrated and covered by a rich glycocalyx, participates in the sieving properties of the glomerular filtration barrier and in the maintenance of podocyte structure. The microvascular endothelium in peritubular capillaries, which is also fenestrated, transports reabsorbed components and participates in epithelial cell function. The endothelium of large and small vessels supports the renal vasculature. These renal endothelia are protected by regulators of thrombosis, inflammation and complement, but endothelial injury (for example, induced by toxins, antibodies, immune cells or inflammatory cytokines) or defects in factors that provide endothelial protection (for example, regulators of complement or angiogenesis) can lead to acute or chronic renal injury. Moreover, renal endothelial cells can transition towards a mesenchymal phenotype, favouring renal fibrosis and the development of chronic kidney disease. Thus, the renal endothelium is both a target and a driver of kidney and systemic cardiovascular complications. Emerging therapeutic strategies that target the renal endothelium may lead to improved outcomes for both rare and common renal diseases.

Heparin-free renal replacement therapy for chronic hemodialyzed patients at high risk for bleeding: a comparison of on-line predilution hemodiafiltration with conventional hemodialysis

BACKGROUND

In chronic hemodialysis patients with high risk of bleeding, optimal anticoagulation of the extracorporeal circuit is challenging. Heparin-free hemodialysis (HD) with heparin-coated AN69ST dialyzer is now considered as a good option and recommended by experts. Predilutional hemodiafiltration (HDF) may represent also a feasible alternative but has been poorly investigated. In this study, our aim was to evaluate the performance of on-line automated predilution heparin-free HDF as compared to conventional heparin-free HD with a heparin-coated membrane.

METHODS

We prospectively studied chronic hemodialysis patients at high risk of bleeding consecutively admitted to hospital who underwent heparin-free renal replacement therapy (RRT) in our nephrology department. During 1 year, we routinely used heparin-free HD and on-line HDF in these settings. By using a propensity score, we compared HDF to HD regarding to session failure and efficiency.

RESULTS

One hundred and seventy-nine patients were included in the study. Clotting phenomena necessitating premature termination of RRT sessions were encountered in 19% of them. After propensity score matching, the comparison of 77 HD and 77 HDF sessions showed no significant differences in duration of the sessions and in dialyzer clotting. By multivariate analysis, a blood flow less than 250 mL/min and recent surgery were the only parameters associated with extracorporeal circuit thrombosis.

CONCLUSION

Heparin-free on-line predilutional HDF is a safe and effective technique for chronic hemodialysis patients with increased bleeding risk. The use of an automatic substitution volume that avoids filters hemoconcentration and of a blood flow above 250 mL/min strongly contribute to the observed performance. Further studies are, however, intended to confirm these results.

Evaluation at 3 years of concurrent bevacizumab and radiotherapy for breast cancer: Results of a prospective study

PURPOSE

To determine the 3 years late toxicity among patients with non-metastatic breast cancer who received concurrent bevacizumab and locoregional radiotherapy.

MATERIAL AND METHODS

This is a single-arm, multicentre, prospective study, of the toxicity of adjuvant concomitant association of bevacizumab and radiotherapy in patients with breast cancer. Toxicity was assessed by the Common Terminology Criteria for Adverse Events version 3.0 during the radiotherapy and follow-up clinics at 12 and 36 months after its completion. The study was designed to evaluate the toxicity at one year, 3 years and 5 years.

RESULTS

Sixty-four patients were included from October 2007 to August 2010. All of them received concurrent adjuvant radiotherapy and bevacizumab (in 24 cases after primary systemic treatment). All patients received non-fractionated radiotherapy to breast or chest wall with or without irradiation of regional lymph nodes. Early toxicity has been previously reported. Median follow-up was 46.4 months (range: 18-77 months). Median age was 53 years old (range: 23-68 years). The 3-years overall survival was 93% (range: 87-100%). Evaluation of the toxicity at 3 years was available for 67% of the patients. There was a low rate of toxicity: 14% grade 1 pain, 9% grade 1 fibrosis, 2% grade 1 telangiectasia, 2% grade 1 paresis, 7% grade 1 lymphedema and 2% grade 3 lymphedema. No grade 4 toxicity was observed. No patient had a left ventricular ejection fraction below 50% at 3 years.

CONCLUSIONS

Concurrent bevacizumab with locoregional radiotherapy is associated with acceptable 3-years toxicity in patients with breast cancer.

Successful treatment of a Streptococcus pneumoniae-associated haemolytic uraemic syndrome by eculizumab

Haemolytic uraemic syndrome (HUS) is a rare complication of invasive infection by Streptococcus pneumoniae (SP-HUS), especially in adults. Here we report an unusual case of a 53-year-old man presenting SP-HUS with severe multivisceral involvement. After failure of supportive care and plasma exchanges, eculizumab (anti-C5 antibody) resulted in a favourable outcome.

Comparison of passive-beam proton therapy, helical tomotherapy and 3D conformal radiation therapy in Hodgkin's lymphoma female patients receiving involved-field or involved site radiation therapy

PURPOSE

Second cancers and cardiovascular toxicities are long term radiation toxicity in locally advanced Hodgkin's lymphomas. In this study, we evaluate the potential reduction of dose to normal tissue with helical tomotherapy and proton therapy for Hodgkin's lymphoma involved-field or involved-site irradiation compared to standard 3D conformal radiation therapy.

PATIENTS AND METHODS

Fourteen female patients with supradiaphragmatic Hodgkin's lymphoma were treated at our institution with 3D conformal radiation therapy or helical tomotherapy to a dose of 30Gy in 15 fractions. A planning comparison was achieved including proton therapy with anterior/posterior passive scattered beams weighted 20Gy/10Gy.

RESULTS

Mean doses to breasts, lung tissue and heart with proton therapy were significantly lower compared to helical tomotherapy and to 3D conformal radiation therapy. Helical tomotherapy assured the best protection of lungs from doses above 15Gy with the V20Gy equal to 16.4%, compared to 19.7% for proton therapy (P=0.01) or 22.4% with 3D conformal radiation therapy (P<0.01). Volumes of lung receiving doses below 15Gy were significantly larger for helical tomotherapy than for proton therapy or 3D conformal radiation therapy, with respective lung doses V10Gy=37.2%, 24.6% and 27.4%. Also, in the domain of low doses, the volumes of breast that received more than 10Gy or more than 4Gy with helical tomotherapy were double the corresponding volumes for proton therapy, with V4Gy representing more than a third of one breast volume with helical tomotherapy.

CONCLUSIONS

Helical tomotherapy achieved a better protection to the lungs for doses above 15Gy than passive proton therapy or 3D conformal radiation therapy. However, dose distributions could generally be improved by using protons even with our current passive-beam technology, especially allowing less low dose spreading and better breast tissue sparing, which is an important factor to consider when treating Hodgkin's lymphomas in female patients. Prospective clinical study is needed to evaluate the tolerance and confirm these findings.

Abstract P3-12-16: Hydrosorb® versus control (water based spray) in the management of radio-induced skin toxicity: Results of multicentre controlled randomized trial

Purpose: To report the results of a randomised study comparing the efficacy of Hydrosorb® versus control (water based spray) in the topical treatment of grade 1 and 2 radiation dermatitis in population of patients treated for early stage breast cancer (BC) with normo fractionated radiotherapy (RT).

Patients and Methods: Breast cancer patients with grade 1-2 radio-induced dermatitis during normo fractionated postoperative radiotherapy were eligible (according to the CTCAE v3 scale). They were randomised to receive either Hydrosorb® (A) or water based spray (B). The primary endpoint was local treatment failure defined as interruption of radiotherapy because of skin radiotoxicity or and/or change of local cares for skin alteration. Secondary endpoints were the evaluation of skin colorimetry, pain, and quality of life. Pain was assessed according to two classes with a VAS cut-off of 2.

Results: Two-hundred seventy eight patients were enrolled (A = 142, B = 136). There were 186 successfully treated patients (82 in Hydrosorb® arm, and 74 in the control arm). There were 60 "failures" in the Hydrosorb® arm, and 62 in the control arm (p = 0.72), but mostly without interruption of the radiotherapy. Twenty-four patients stopped the radiotherapy treatment for local cares (16 in Hydrosorb®, arm and 8 in control arm). No risk factors were associated with failure to local treatment. The average absolute reduction of colorimetric levels between day 28 and day 0 was 4 in the Hydrosorb®, and 4.2 in the water spray groups, respectively (p = 0.36). Forty-eight patients in the Hydrosorb® arm had a VAS &gt; 2 versus 51 patients in the placebo arm, i.e. 34% and 38%, respectively (p = 0.45). A significant reduction of pain was observed on D7 (p = 0.04) and D21 (p = 0.01) in the Hydrosorb® arm. Sixty patients in the Hydrosorb® arm and 55 patients in the placebo arm had moderately to severely altered quality of life (p = 0.76).

Conclusions: The present study showed no significant difference between Hydrosorb® and simple water spray in the treatment of acute radio-induced dermatitis even if there was a trend to an improvement in pain at the first weeks after the treatment. Systematic prevention measures and modern breast cancer radiotherapy techniques now allow excellent tolerability, but the place of topical treatment to optimize this tolerability has yet to be defined.

Citation Format: Bazire L, Fromentin I, Diallo A, de Lalande B, Pernin V, Dendale R, Fourquet A, Savignoni A, Kirova Y. Hydrosorb® versus control (water based spray) in the management of radio-induced skin toxicity: Results of multicentre controlled randomized trial. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-12-16.

Late toxicities and outcomes of adjuvant radiotherapy combined with concurrent bevacizumab in patients with triple-negative non-metastatic breast cancer

OBJECTIVE

To evaluate the safety of the concurrent combination of bevacizumab with adjuvant radiotherapy (B-RT) in breast cancer (BC).

METHODS

Multicentre, prospective study, of the toxicity of adjuvant radiotherapy (RT) alone or B-RT in patients with non-metastatic BC enrolled in randomized Phase 3 BEATRICE trial. Early and late toxicities were assessed by the Common Terminology Criteria for Adverse Events v. 3.0 during and 12 months after the completion of RT.

RESULTS

From 2007 to 2012, 39 females received adjuvant B-RT and 45 received adjuvant RT alone. Median follow-up was 21.5 months. All patients had triple-negative non-metastatic BC and received adjuvant chemotherapy followed by RT. 90% of the 39 females treated by concurrent B-RT received whole breast irradiation (WBI) with a boost and 4 (10%) received post-mastectomy RT. Lymph node RT was delivered in 49% of the females with internal mammary chain irradiation. The mean duration of bevacizumab was 11.7 months. 38 (84%) females treated by RT alone received WBI with a boost and 16% of the females received post-mastectomy RT. Lymph node RT was delivered in 47% of the females with internal mammary chain RT in 31%. Grade 3 acute dermatitis was observed in 9% of patients receiving B-RT and 5% of patients receiving RT alone with no significant difference. 1 year after the completion of RT, the most common late grade 1-2 toxicities in the B-RT group were pain (18%), fibrosis (8%) and telangiectasia (5%).

CONCLUSION

The concurrent bevacizumab with locoregional RT is associated with acceptable early and late 1-year toxicities in patients with BC.

ADVANCES IN KNOWLEDGE

The largest series of this association.

[PARP inhibitors and radiotherapy: rational and prospects for a clinical use]

Poly(ADP-ribosyl)ation is a ubiquitous protein modification involved in the regulation of many cellular processes that is carried out by the poly(ADP-ribose) polymerase (PARP) family. The PARP-1, PARP-2 and PARP-3 are the only PARPs known to be activated by DNA damage. The absence of PARP-1 and PARP-2, that are both activated by DNA damage and participate in DNA damage repair processes, results in hypersensitivity to ionizing radiation and alkylating agents. PARP inhibitors that compete with NAD(+) at the enzyme's activity site can be used in BRCA-deficient cells as single agent therapies acting through the principle of synthetic lethality exploiting these cells deficient DNA double-strand break repair. Preclinical data showing an enhancement of the response of tumors to radiation has been documented for several PARP inhibitors. However, whether this is due exclusively to impaired DNA damage responses or whether tumor re-oxygenation contributes to this radio-sensitization via the vasoactive effects of the PARP inhibitors remains to be fully determined. These promising results have paved the way for the evaluation of PARP inhibitors in combination with radiotherapy in phase I and phase II clinical trials for malignant glioma, head and neck, and breast cancers. A number of challenges remain that are also reviewed in this article, including the optimization of treatment schedules for combined therapies and the validation of biomarkers that will identify which patients will most benefit from either PARP inhibitors in combination with radiotherapy.

Radiotherapy for breast cancer and erythrokeratodermia variabilis

We report the first case report indicating that locoregional radiotherapy provide acceptable early and late toxicities in patient with erythrokeratodermia variabilis after 2 years of follow-up. However, preclinical data showing radiation-induced tumor genesis in case of deficiency of some connexins point out the need of a careful surveillance of these patients.