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Previous studies have reported that lung transplant recipients (LTR) develop a poor response to two doses of COVID-19 vaccine, but data regarding the third dose are lacking. We investigated the antibody response after three doses of mRNA vaccine in LTR and its predictive factors.A total of 136 LTR, including 10 LTR previously infected and 126 COVID-19-naive LTR, were followed during and after three doses of mRNA vaccine. We retrospectively measured anti-receptor-binding domain (RBD) IgG response and neutralizing antibodies. In a posthoc analysis, we used a multivariate logistic regression model to assess the association between vaccine response and patient characteristics, including viral DNA load (VL) of the ubiquitous Torque teno virus (TTV) (optimal cut-off set by ROC curve analysis), which reflects the overall immunosuppression.After 3 doses, 47/126 (37.3%) COVID-19-naive LTR had positive anti-RBD IgG (responders) and 14/126 (11.1%) had antibody titers above 264 Binding Antibody Units/mL. None neutralized the omicron variant versus 7 of the 10 previously infected LTR. Nonresponse was associated with TTV VL ≥6.2 logCOVID-19-naive LTR respond poorly to three doses of mRNA vaccine, especially those with high TTV VL. Future studies could further evaluate this biomarker as a guide for vaccine strategies.

While loss-of-function variants in the WAS gene are associated with Wiskott-Aldrich syndrome and lead to microthrombocytopenia, gain-of-function variants of WAS are associated with X-linked neutropenia (XLN) and the absence of microthrombocytopenia. Only a few XLN families have been reported so far, and their platelet phenotype was not described in detail. To date, no renal involvement was described in XLN. In the present study, we report exome sequencing of individuals from 3 generations of a family with a dominant disease combining neutropenia, macrothrombocytopenia, and renal failure. We identified a heterozygous missense gain-of-function variant in the WAS gene (c.881T>C, p.I294T) that segregates with the disease and is already known to cause XLN. There was no pathogenic variant in MYH9, TUBB1, or ACTN1. This is the first report of a WAS gain-of-function variant associated with both the hematological phenotype of XLN (neutropenia, macrothrombocytopenia) and renal disease (proteinuria, renal failure) with glomerular tip lesion hyalinosis and actin condensations in effaced podocytes foot processes.

Background The standard-of-care protocol, based on plasma exchanges, high-dose intravenous immunoglobulin and optimization of maintenance immunosuppression, can slow down the evolution of antibody-mediated rejection (AMR), but with high interindividual variability. Identification of a reliable predictive tool of the response to AMR treatment is a mandatory step for personalization of the follow-up strategy and to guide second-line therapies. Methods Interrogation of the electronic databases of 2 French university hospitals (Lyon and Strasbourg) retrospectively identified 81 renal transplant recipients diagnosed with AMR without chronic lesions (cg score ≤1) at diagnosis and for whom a follow-up biopsy had been performed 3–6 months after initiation of therapy. Results The evolution of humoral lesions on follow-up biopsy (disappearance versus persistence versus progression) correlated with the risk for allograft loss (logrank test, P = .001). Patients with disappearance of humoral lesions had ∼80% graft survival at 10 years. The hazard ratio for graft loss in multivariate analysis was 3.91 (P = .04) and 5.15 (P = .02) for patients with persistence and progression of lesions, respectively. The non-invasive parameters classically used to follow the intensity of humoral alloimmune response (evolution of immunodominant DSA mean fluorescence intensity) and the decline of renal graft function (estimated glomerular filtration rate decrease and persistent proteinuria) showed little clinical value to predict the histological response to AMR therapy. Conclusion We conclude that invasive monitoring of the evolution of humoral lesions by the mean of follow-up biopsy performed 3–6 months after the initiation of therapy is an interesting tool to predict long-term outcome after AMR treatment.

Kidney transplant recipients (KTRs) are prone to develop severe COVID-19 and are less well protected by vaccine than immunocompetent subjects. Thus, the use of neutralizing anti-SARS-CoV-2 monoclonal antibody (MoAb) to confer a passive immunity appears attractive in KTRs.We performed a French nationwide study to compare COVID-19-related hospitalization, 30-day admission to intensive care unit (ICU), and 30-day death between KTRs who received an early infusion of MoAb (MoAb group) and KTRs who did not (control group). Controls were identified from the COVID-SFT registry (NCT04360707) using a propensity score matching with the following covariates: age, sex, delay between transplantation and infection, induction and maintenance immunosuppressive therapy, initial symptoms, and comorbidities.A total of 80 KTRs received MoAb between February 2021 and June 2021. They were matched to 155 controls. COVID-19-related hospitalization, 30-day admission to ICU, and 30-day death were less frequently observed in the MoAb group (35.0% vs. 49.7%,The early use of MoAb in KTRs with a mild form of COVID-19 largely improved outcomes in KTRs.

International audience; Cytomegalovirus (CMV) persists as the most frequent opportunistic infection among solid organ transplant recipients. This multicenter trial aimed to test whether treatment with everolimus (EVR) could decrease the incidence of CMV DNAemia and disease. We randomized 186 CMV seropositive kidney transplant recipients in a 1:1 ratio to receive EVR or mycophenolic acid (MPA) in association with basiliximab, cyclosporin, and steroids and 87 in each group were analyzed. No universal prophylaxis was administered to either group. The composite primary endpoint was the presence of CMV DNAemia, CMV treatment, graft loss, death, and discontinuation of the study at 6 months posttransplant. In the modified intent-to-treat analysis, 42 (48.3%) and 70 (80.5%) patients in the EVR and MPA groups reached the primary endpoint (OR = 0.21, 95% CI: 0.11-0.43, p

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INTRODUCTION There are only scarce data regarding the cardiovascular impact of arteriovenous fistula after kidney transplantation depending on fistula flow. METHODS We performed a single-center, prospective, cohort study including 49 patients with a functional fistula at 1 year from kidney transplantation. Patients were convened for a clinical work-up, a biological analysis, a fistula's Doppler ultrasonography and an echocardiography. Main judgment criterion was comparison of echocardiography parameters between patients with relative (fistula flow >1 L/min and a fistula flow/cardiac output ratio >20%), absolute high-flow fistula (fistula flow >2 L/min) and normal-flow fistula. RESULTS High-flow fistula frequency was 69%. Significantly higher left ventricular end-diastolic and systolic diameters were observed in this group compared with the normal-flow fistula group (53 ± 6 vs. 48 ± 7 mm; p = 0.04 and 33 ± 6 vs. 28 ± 8 mm; p = 0.02) and between the absolute and relative high-flow fistula subgroups (56 ± 6 vs. 51 ± 6 mm; p = 0.009 and 35 ± 6 vs. 31 ± 5 mm; p = 0.01). The study showed no other significant differences. CONCLUSIONS This study showed a significantly higher but not pathological left ventricular end-diastolic and systolic diameters values in patients with high-flow fistula compared with patients with normal-flow fistula and between patients with respectively absolute and relative high-flow fistula.

Supplemental Digital Content is available in the text., Background. Data on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence in kidney transplant recipients (KTRs) remain rare. We sought to shed further light on this issue by conducting a single-center study in a kidney transplant center located in one of the France’s highest risk zone (Grand Est) for coronavirus disease 2019 (Covid-19) during the initial disease outbreak. Methods. To this aim, we used a survey approach coupled with systematic investigation of SARS-CoV-2 serology in a cohort of 1390 KTRs. Results. SARS-CoV-2 serologies were available for 780 survey respondents, among whom 48 had anti-SARS-CoV-2 antibodies (total seroprevalence: 6.2%). Thirty-five of the 48 seropositive KTRs had previously received a diagnosis of Covid-19, whereas the remaining 13 patients were not known to be infected (8 asymptomatic cases). Specifically, 18.7% of seropositive KTRs and 1.1% of the entire cohort were asymptomatic. Household exposure was found to markedly increase the risk of SARS-CoV-2 transmission. Conclusions. Our findings demonstrate that the overall SARS-CoV-2 seroprevalence in KTRs living in one of the France’s highest risk zone for Covid-19 during the first French lockdown was as low as 6.3%. Rapid and strict implementation of protective measures could have significantly mitigated virus spread even in an area of high virus circulation.

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

International audience; BACKGROUND: The first wave of the Covid-19 pandemic resulted in a drastic reduction in kidney transplantation and a profound change in transplant care in France. It is critical for kidney transplant centers to understand the behaviors, concerns and wishes of transplant recipients and waiting list candidates. METHODS: French kidney patients were contacted to answer an online electronic survey at the end of the lockdown. RESULTS: At the end of the first wave of the pandemic in France (11 May 2020), 2112 kidney transplant recipients and 487 candidates answered the survey. More candidates than recipients left their home during the lockdown, mainly for health care (80.1% vs. 69.4%; P\textless0.001). More candidates than recipients reported being exposed to Covid-19 patients (2.7% vs. 1.2%; P=0.006). Many recipients and even more candidates felt inadequately informed by their transplant center during the pandemic (19.6% vs. 54%; P\textless0.001). Among candidates, 71.1% preferred to undergo transplant as soon as possible, 19.5% preferred to wait until Covid-19 had left their community, and 9.4% were not sure what to do. CONCLUSIONS: During the Covid-19 pandemic in France, the majority of candidates wished to receive a transplant as soon as possible without waiting until Covid-19 had left their community. Communication between kidney transplant centers and patients must be improved to better understand and serve patients' needs.

Résumé La pandémie Covid-19 frappe la population de transplantés français dès le 3 mars 2020. Très rapidement, un registre français s’est mis en place sous l’égide de la Société francophone de transplantation permettant de colliger les cas de Covid-19 confirmés survenant chez des patients transplantés de rein dans la quasi-totalité des centres français. L’analyse de ce registre conjointement à celle des données du registre Cristal de l’Agence de la Biomédecine a permis d’aboutir à des premiers résultats instructifs. Nous avons d’abord montré que l’incidence des formes sévères au sein des patients transplantés hospitalisés pour Covid-19 était de 46 % et que leur mortalité était de 22,8 %. Les facteurs de risque de formes sévères et de mortalité sont décrits. Nous avons ensuite montré, en comparant les transplantés à des patients immunocompétents appariés pour les principaux facteurs de gravité de cette maladie, que la mortalité des patients transplantés était plus élevée parmi des transplantés (17,9 % vs 11,4 % ; p

ObjectiveThis single-center retrospective study evaluated the use of tixagevimab-cilgavimab as an early treatment for COVID-19 in kidney transplant recipients (KTRs) during the omicron wave.MethodsKTRs were deemed at high risk for moderate-to-severe COVID-19 in presence of at least one comorbidity (age >60 years, diabetes, obesity, or cardiovascular disease) associated with a weak humoral response (ResultsOf the 61 KTRs at high risk, 26 received tixagevimab-cilgavimab. COVID-19-related hospitalizations (3.8% versus 34%, p=0.006) and oxygen need (3.8% versus 23%, p=0.04) were significantly less frequent in patients who received tixagevimab-cilgavimab. In addition, non-significant trends towards a lower number of ICU admissions (3.8% versus 14.3% p=0.17) and deaths (0 versus 3, p=0.13) were observed after administration of tixagevimab-cilgavimab. Ten of the 73 low-risk KTRs received tixagevimab-cilgavimab, and no significant clinical benefit was observed in this subgroup.ConclusionEarly administration of tixagevimab-cilgavimab may be clinically useful in high-risk KTRs with COVID-19; however, no major benefit was observed for low-risk patients.

Solid organ transplant recipients are at high risk for fatal forms of coronavirus disease 2019 (COVID-19). We conducted a cohort study among kidney transplant (KT) recipients from the French Solid Organ Transplant COVID-19 Registry to investigate the association between maintenance immunosuppressive drugs and 60-d mortality.Data from all KT recipients with COVID-19 included in the French Solid Organ Transplant COVID-19 Registry between February 28, 2020, and December 30, 2020, were retrieved. We evaluated associations between immunosuppressive drugs and death within 60 d using logistic regression, with all baseline characteristics considered to influence outcome or immunosuppressive regimen. The Benjamini-Hochberg correction was used for controlling false positive rate; 40 multiple imputations were performed. Adjusted P value0.05 was considered statistically significant.There were 1451 KT recipients included. Median age was 58 y, and 66.4% were men. Most frequent comorbidities were hypertension (81.9%), diabetes (34.5%), and cardiovascular disease (29.5%). Median time since transplant was 71 mo. Maintenance immunosuppression regimens included calcineurin inhibitors (1295, 89.2%), antimetabolites (1205, 83%), corticosteroids (1094, 75.4%), mammalian target of rapamycin inhibitors (144, 9.9%), and belatacept (58, 4.0%). Among 1451 transplant recipients, 201 (13.9%) died within 60 d. Older age and higher baseline serum creatinine were associated with mortality (odds ratios, 1.09 [1.07-1.11] and 1.01 [1.005-1.009], P0.001). Corticosteroid-free regimens were associated with a significantly lower risk of death (odds ratio, 0.48 [0.31-0.76]; P = 0.011).Corticosteroid-free regimens were associated with a lower risk of death in KT recipients with COVID-19. Long-term exposure to corticosteroids impairs immune functions and may predispose solid organ transplant recipients to severe forms of COVID-19.

To assess the aetiology, clinical features, diagnostic studies and outcomes of community-acquired pneumonia (CAP) in a French cohort of hospitalized kidney transplant recipients kidney transplant recipients.We performed a retrospective, multicenter study in kidney transplant recipients admitted to 10 French centers for CAP from January 2016 to December 2018. CAP discharge diagnoses were clinically and radiologically validated. We assessed a descriptive analysis of all confirmed CAP including medical ward and intensive care unit (ICU) admissions.165 CAP episodes in 132 patients were included. Median time from transplantation to admission was 6.4 [IQR, 1.6-12.3] years, with corticosteroid exposure in 112/165 (67.9%) cases. Sputum culture was performed in 47/165 (28.5%) cases including 7/47 (14.9%) positive samples. Bronchoscopy was performed in 87/165 (52.7%) cases with pathogens identified in 39/87 (44.8%) cases. Microbiological studies led to identify a respiratory pathogen in 64/165 (38.8%) CAP episodes including 11/64 (17.2%) polymicrobial cases. Among these 64 episodes, 75 micro-organisms were identified; 46/75 (61.3%) core respiratory pathogens and 29/75 (38.7%) opportunistic or drug-resistant organisms including Pneumocystis jirovecii 9/75 (12%), Pseudomonas aeruginosa 5/75 (6.7%), multidrug-resistant Enterobacteriaceae 4/75 (5.3%) and Aspergillus 4/75 (5.3%). Patients required ICU admission in 26/165 (15.8%) episodes, invasive ventilation in 20/165 (12.1%) cases and 22/165 (13.3%) needed in-hospital dialysis.CAP episodes occurred in KTR with a long history of immunosuppressive drug exposure. Diagnostic studies identified a micro-organism in more than one third of CAP episodes, including drug-resistant and opportunistic pathogens.

The cilgavimab-tixagevimab combination retains a partial in vitro neutralizing activity against the current SARS-CoV-2 variants of concern (omicron BA.1, BA.1.1, and BA.2). Here, we examined whether preexposure prophylaxis with cilgavimab-tixagevimab can effectively protect kidney transplant recipients (KTRs) against the omicron variant. Of the 416 KTRs who received intramuscular prophylactic injections of 150 mg tixagevimab and 150 mg cilgavimab, 39 (9.4%) developed COVID-19. With the exception of one case, all patients were symptomatic. Hospitalization and admission to an intensive care unit were required for 14 (35.9%) and three patients (7.7%), respectively. Two KTRs died of COVID-19-related acute respiratory distress syndrome. SARS-CoV-2 sequencing was carried out in 15 cases (BA.1, n = 5; BA.1.1, n = 9; BA.2, n = 1). Viral neutralizing activity of the serum against the BA.1 variant was negative in the 12 tested patients, suggesting that this prophylactic strategy does not provide sufficient protection against this variant of concern. In summary, preexposure prophylaxis with cilgavimab-tixagevimab at the dose of 150 mg of each antibody does not adequately protect KTRs against omicron. Further clarification of the optimal dosing can assist in our understanding of how best to harness its protective potential.

BackgroundRepeated vaccination against SARS-CoV-2 increases serological response in kidney transplant recipients (KTR) with high interindividual variability. No decision support tool exists to predict SARS-CoV-2 vaccination response in KTR.MethodsWe developed, internally and externally validated five different multivariable prediction models of serological response after the third and fourth vaccine dose against SARS-CoV-2 in KTR. Using 27 candidate predictor variables, we applied statistical and machine learning approaches including logistic regression (LR), LASSO-regularized LR, random forest, and gradient boosted regression trees. For development and internal validation, data from 585 vaccinations were used. External validation was performed in four independent, international validation datasets comprising 191, 184, 254, and 323 vaccinations, respectively.FindingsLASSO-regularized LR performed on the whole development dataset yielded a 23- and 11- variable model, respectively. External validation showed AUC-ROC of 0.855, 0.749, 0.828, and 0.787 for the sparser 11-variable model, yielding an overall performance 0.819.InterpretationAn 11-variable LASSO-regularized LR model predicts vaccination response in KTR with good overall accuracy. Implemented as an online tool, it can guide decisions when choosing between different immunization strategies to improve protection against COVID-19 in KTR.

Kidney transplant recipients (KTRs) displays marked inter-individual variations in magnitude of immune responses to anti-SARS-CoV-2 vaccination. The aim of this large single-center study was to identify the predictive factors for serological response to the mRNA-1273 vaccine in KTRs. We also devised a score to optimize prediction with the goal of implementing a personalized vaccination strategy. The study population consisted of 564 KTRs who received at least two doses of the mRNA-1273 vaccine. Anti-RBD IgG titers were quantified one month after each vaccine dose and until six months thereafter. A third dose vaccine was given when the antibody titer after the second dose was

Kidney transplant recipients (KTRs) are frequently infected with chronic hepatitis C virus (HCV), which can increase the risk of graft loss. Active HCV infections among KTRs are associated with shorter survival times. The emergence of very efficient interferon-free treatments (direct-acting antivirals [DAAs]) has revolutionized prognoses for chronic viral hepatitis. We performed a multicenter study where HCV (+)/RNA (+) KTRs were followed up and either received DAAs (group A) or not (group B) according to the transplant center. The aim was to assess, in a real-life setting, the impact of DAA therapy and to compare these results with those from HCV RNA (+) KTRs where HCV infection was not treated during the same period.This study included 66 patients from 11 centers: 44 patients (66.7%; group A) received DAAs, whereas 22 patients did not (group B); the 2 groups were comparable according to baseline data. Most patients (88.6%) received sofosbuvir, 50% received ledipasvir, and 34.7% received daclatasvir. The duration of treatments ranged from 8 to 24 weeks.HCV RNA clearance (ie, a sustained virologic response) was observed in 95.4% of treated patients. Eradication of HCV led to a significant decrease in liver enzymes (50% reduction for alanine aminotransferase [P ≤ .001] and 41% for gamma glutamyl transpeptidase [P .001]). Conversely, liver enzymes did not decrease in group B. Death occurred significantly more frequently in nontreated than treated patients (3 in group B vs none in group A, P = .003). Of the 10 treated patients with severe renal impairment before DAA therapy, 6 experienced graft loss.DAAs are very effective at treating chronic HCV and have an excellent tolerance profile.

The combination of cilgavimab-tixagevimab (Evusheld™, Astra Zeneca) became the mainstay for protecting transplant recipients with poor response to vaccination against the omicron variant. Serum neutralizing capacity against SARS-CoV-2 is positively associated with protection against severe forms of Covid-19.Both anti-RBD IgG titers and neutralizing antibody titers against the omicron BA.1 variant were measured in serum samples collected from 63 adult kidney transplant recipients who received prophylactic injections of Evusheld™. Patients who received prophylactic Ronapreve™ (casirivimab-imdevimab, n = 39) and those who were infected with SARS-CoV-2 during the fifth wave of the pandemic (n = 14) served as negative and positive controls, respectively.After a median interval from injection of 29 days (interquartile range 29-33 days), only 9.5% of patients who received Evusheld™ were able to neutralize the omicron variant compared to 71% of patients who were infected with SARS-CoV-2 and 2.6% of those who received Ronapreve™. Interestingly, convalescent patients displayed higher levels of neutralizing antibodies than those who received EvusheldTM (median: 2.3 log IC50, IQR: 1.5-2.7 versus 0.00 log IC50, IQR: 0&[ndash] 0.05; pThese findings suggest that Evusheld™ given at a dose of 300 mg is not sufficient to elicit an anti-RDB titer that confers in vivo neutralizing activity and support recent FDA recommendations, derived from in vitro models, regarding the need to increase the dose of Evusheld™

While the combination of casirivimab-imdevimab (Ronapreve™ Roche Regeneron) has been shown to confer satisfactory protection against the delta variant kidney transplant recipients (KTRs) with COVID-19, it has limited neutralizing activity against the current variants of concern (Omicron BA.1, BA.1.1 and BA.2). In contrast, cilgavimab-tixagevimab combination (Evusheld™, Astra Zeneca) retains a partial neutralizing activity against omicron in vitro. We examined whether preexposure prophylaxis with Evusheld™ can effectively protect kidney transplant recipients (KTRs) against the Omicron variant.Of the 416 KTRs who received intramuscular prophylactic injections of Evusheld™ (150 mg tixagevimab and 150 mg cilgavimab), 39 (9.4%) developed COVID-19. With the exception of one patient, all KTRs were symptomatic. Hospitalization and admission to an intensive care unit were required for 14 (35.9%) and three patients, respectively. Two KTRs died of COVID-19-related acute respiratory distress syndrome. SARS-CoV-2 sequencing was carried out in 15 cases (BA.1, n = 5; BA.1.1, n = 9; BA.2, n=1). Viral neutralizing activity of the serum against BA.1 variant was negative in the 12 tested patients, suggesting that this prophylaxis strategy provides insufficient protection against this variant of concern.Preexposure prophylaxis with Evusheld™ does not adequately protect KTRs against Omicron. Further clarification of the optimal dosing can assist in our understanding of how best to harness its protective potential.

Transplant recipients, who receive therapeutic immunosuppression to prevent graft rejection, are characterized by high coronavirus disease 2019 (COVID-19)–related mortality and defective response to vaccines. We observed that previous infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but not the standard two-dose regimen of vaccination, provided protection against symptomatic COVID-19 in kidney transplant recipients. We therefore compared the cellular and humoral immune responses of these two groups of patients. Neutralizing anti–receptor-binding domain (RBD) immunoglobulin G (IgG) antibodies were identified as the primary correlate of protection for transplant recipients. Analysis of virus-specific B and T cell responses suggested that the generation of neutralizing anti-RBD IgG may have depended on cognate T-B cell interactions that took place in germinal center, potentially acting as a limiting checkpoint. High-dose mycophenolate mofetil, an immunosuppressive drug, was associated with fewer antigen-specific B and T follicular helper (TFH) cells after vaccination; this was not observed in patients recently infected with SARS-CoV-2. Last, we observed that, in two independent prospective cohorts, administration of a third dose of SARS-CoV-2 mRNA vaccine restored neutralizing titers of anti-RBD IgG in about 40% of individuals who had not previously responded to two doses of vaccine. Together, these findings suggest that a third dose of SARS-CoV-2 mRNA vaccine improves the RBD-specific responses of transplant patients treated with immunosuppressive drugs.

Kidney transplant recipients (KTR) are at increased risk of fractures. Total urinary hydroxyproline excretion used to be a marker for bone resorption (BR) but faded into the background when more specific markers like Beta-CrossLaps (CTX) became available. Proteomic studies identified numerous hydroxyproline-containing urinary collagen peptides but their origin remains unknown. We followed the hypothesis that some of the urinary collagen peptides are associated with BR and are markers for pathophysiological changes in bone metabolism of KTR. Clinical and laboratory data including serum levels of CTX in 96 KTR from two French centers (Strasbourg, n=38; Paris-Necker, n=58) were correlated with the signal intensity of urinary peptides identified by capillary electrophoresis (CE) coupled to mass spectrometry (MS) and tandem-MS. The effect of oral bisphosphonates on urinary peptides was studied in an independent group of 11 KTR. Eighty-two urinary peptides were identified to be significantly correlated with serum CTX levels in both cohorts. Statistical association with parameters other than BR markers were not significant. Collagen α-1(I) chain (COL1A1) was the most frequently identified peptide source. COL1A1 peptides associated with BR were significantly more hydroxylated than those showing no association (55.9% versus 45,2%, p2-test). From the 82 urinary peptides correlated to CTX, 17 were significantly associated with bisphosphonate treatment. All of these 17 peptides showed a marked reduction in their excretion levels after 410 ± 344 days of bisphosphonate treatment compared to baseline levels. We studied the cleavage sites of these COL1A1 peptides and observed a signature of Cathepsin K and Matrix Metallopeptidase 9. This study provides strong evidence for the occurrence of collagen peptides in the urine of KTR that are associated with BR and that are sensitive to bisphosphonate treatment. Their assessment might become a valuable tool to monitor bone status in KTR.

Background Belatacept (bela) rescue therapy seems to be a valuable option for calcineurin inhibitor chronic toxicity in kidney transplantation. Nevertheless, the risk of infection associated with bela is not well reported. Methods We report the rate of opportunistic infections (OPI) after a switch to bela in a multicentric cohort of 280 kidney transplant patients. Results Forty-two OPI occurred in 34 patients (12.1%), on average 10.8 ± 11.3 months after the switch. With a cumulative exposure of 5128 months of bela treatment, we found an incidence of 0.008 OPI/month of exposure, and 9.8 OPI/100 person-years. The most common OPI was cytomegalovirus (CMV) disease in 18/42 OPI (42.9%) and pneumocystis pneumonia in 12/42 OPI (28.6%). Two patients presented a progressive multifocal leucoencephalopathy and two patients developed a cerebral Epstein–Barr virus-induced post-transplant lymphoproliferative disease. OPI led to death in 9/34 patients (26.5%) and graft failure in 4/34 patients (11.8%). In multivariate analysis, estimated glomerular filtration rate Conclusions The risk of OPI is significant post-conversion to bela and may require additional monitoring and prophylactic therapy, particularly regarding pneumocystis pneumonia and CMV disease. These data need to be confirmed in a larger case–control study.

Introduction: The purpose of this study was to evaluate the efficacy of polycystic kidney embolization, performed to reduce kidney volume before heterotopic kidney transplantation, as this technique could be an alternative to pretransplant nephrectomy. Materials and Methods: All patients who underwent pretransplant embolization of polycystic kidneys were included in a prospective register from June 2014 to February 2020. All patients underwent computed tomography (CT) scan with volumetric reconstruction (OsiriX, Bernex, Switzerland) before embolization and were then followed up at 3 and 6 months after embolization. Primary outcome was percentage of kidney volume reduction. Secondary outcomes were 30 day mortality and morbidity. Results: Thirty-one embolizations performed on 29 patients (medium age = 55.6; 62.1% male) were included between June 2014 and February 2020. All patients were under dialysis before embolization (9 peritoneal dialysis and 20 hemodialysis). Technical success was observed in 96.8% of cases. Mean procedural time was 65 minutes (range = 35–106 minutes) and mean length of in-hospital stay was 3.8 days (range = 3–6 days). A volume reduction allowing a kidney transplant was obtained for 28 patients (96.5%). The mean volume reduction was 39.9% (range = 6.01–68.2). The main observed complication was postembolization pain in 10 cases (32.2%). One patient needed complementary nephrectomy due to insufficient volume reduction. Twenty-three patients (79.3%) received renal transplant during follow-up with a mean delay of 19.5 month (range = 4–54). Conclusion: Polycystic kidney embolization is an effective and safe minimally invasive technique. It can be proposed as the first-choice technique for kidney transplant recipients as an alternative to pretransplantation nephrectomy.

De novo donor-specific antibodies (DSAs) are associated with antibody-mediated rejection (AMR) and allograft loss. Whether monitoring of de novo DSA (dnDSA) paired with systematic kidney biopsy should become routine remains to be established.A retrospective multicentric study (9 French kidney transplant units of the Spiesser group) included patients without graft dysfunction biopsied because of the presence of dnDSA (One Lambda, mean fluorescence intensity [MFI],1000).One hundred twenty-three patients (85 male/38 female; mean age, 49.5 ± 13.1 y old) were biopsied after the detection of a dnDSA, 65.3 months (median) after kidney transplantation. Graft function was stable within 3 months before biopsy (estimated glomerular filtration rate, 55.3 ± 18.9 mL/min/1.73 m). Fifty-one subclinical AMRs (sAMRs) (41.4%) were diagnosed, of which 32 (26%) active and 19 (15.5%) chronic active sAMR. Seventy-two biopsies revealed no AMR (58.5%). Predictive factors associated with the diagnosis of active sAMR were MFI of immunodominant DSA4000, MFI of the sum of DSA6300, age of the recipient45 years old, and the absence of steroids at biopsy. The presence of proteinuria200 mg/g was predictive of chronic active sAMR. The decrease of estimated glomerular filtration rate at 5 years post-biopsy was significantly higher in patients with acute sAMR (-25.2 ± 28.3 mL/min/1.73 m) and graft survival significantly lower.Performing a kidney graft biopsy for the occurrence of dnDSA without renal dysfunction leads to the diagnosis of a sAMR in over 40% of cases. Nevertheless, we did not observe any effect of standard treatment in acute sAMR.

Background Autosomal dominant polycystic kidney disease (ADPKD) is a common genetic disorder associated with progressive enlargement of the kidneys and liver. ADPKD patients may require renal volume reduction, especially before renal transplantation. The standard treatment is unilateral nephrectomy. However, surgery incurs a risk of blood transfusion and alloimmunization. Furthermore, when patients are treated with peritoneal dialysis (PD), surgery is associated with an increased risk of temporary or definitive switch to haemodialysis (HD). Unilateral renal arterial embolization can be used as an alternative approach to nephrectomy. Methods We performed a multicentre retrospective study to compare the technique of survival of PD after transcatheter renal artery embolization with that of nephrectomy in an ADPKD population. We included ADPKD patients treated with PD submitted to renal volume reduction by either surgery or arterial embolization. Secondary objectives were to compare the frequency and duration of a temporary switch to HD in both groups and the impact of the procedure on PD adequacy parameters. Results More than 700 patient files from 12 centres were screened. Only 37 patients met the inclusion criteria (i.e. treated with PD at the time of renal volume reduction) and were included in the study (21 embolized and 16 nephrectomized). Permanent switch to HD was observed in 6 embolized patients (28.6%) versus 11 nephrectomized patients (68.8%) (P = 0.0001). Renal artery embolization was associated with better technique survival: subdistribution hazard ratio (SHR) 0.29 [95% confidence interval (CI) 0.12–0.75; P = 0.01]. By multivariate analysis, renal volume reduction by embolization and male gender were associated with a decreased risk of switching to HD. After embolization, a decrease in PD adequacy parameters was observed but no embolized patients required temporary HD; the duration of hospitalization was significantly lower [5 days [interquartile range (IQR) 4.0–6.0] in the embolization group versus 8.5 days (IQR 6.0–11.0) in the surgery group. Conclusions Transcatheter renal artery embolization yields better technique survival of PD in ADPKD patients requiring renal volume reduction.

SARS-CoV-2 pandemic evolved in two consecutive waves over 2020 (for France: 1st wave from March 1 to July 31; and 2nd wave from August 1 to December 31). Improvements in the management of COVID-19 led to a reduction of mortality rates in hospitalized patients during the second wave. Whether this progress also benefited to kidney transplant recipients (KTR), a population particularly vulnerable to severe COVID-19, remained unclear.In France, 957 KTR were hospitalized for COVID-19 in 2020 and their data were prospectively collected in the French SOT COVID registry. The presentation, management, and outcomes of the 359 KTR diagnosed during the 1st wave were compared to those of the 598 of the 2nd wave. Baseline comorbidities were largely similar between KTR of the 2 waves. Maintenance immunosuppression was reduced in most patients but withdrawal of antimetabolite (73.7% vs 58.4%, pWe conclude that changing of therapeutic trends during 2020 did not reduce COVID-19 related mortality in KTR. Our data indirectly support the importance of vaccination and monoclonal neutralizing anti-SARS-CoV-2 antibodies to protect KTR from severe COVID-19.

The COVID-19 pandemic affects the transplant recipients since March 2020. Transplant centers quickly organized themselves to optimize the management of the immunocompromised patients and to progress in the knowledge of this new disease. To this end, a French Registry was created, which includes all solid organ transplant patients who have developed a SARS Cov2 infection. Numerous studies have been carried out using these data to describe this new disease in transplant patients, to characterize its clinical and biological risk factors and to define its prognosis. The 60 days-mortality of transplant patients hospitalized for COVID-19 was evaluated at 23% and renal failure plays a major role in the poor prognosis in addition to the classical risk factors described in the general population. The advent of vaccination has been a great relief but transplanted patients have shown a poor vaccine response keeping them at risk of severe disease even after an adapted vaccination scheme. Specific strategies was proposed in this particularly fragile population like increasing vaccine doses or using anti SARS Cov-2 monoclonal antibodies.

SARS-CoV-2 is the cause of worldwide COVID-19, which severity has been linked to the immune and inflammatory response. Here, we investigate Torquetenovirus (TTV) DNA load - a marker reflecting the intensity of the overall immune response - as well as SARS-CoV-2 RNAemia and IgM/IgG antibodies in COVID-19-positive patients.Two hundred and fifteen COVID-19-positive patients were enrolled, including 87 severe cases and 128 mild-moderate cases. SARS-CoV-2 RNAemia and IgM/IgG antibodies, as well as TTV DNA loads, were measured on longitudinal plasma samples.The rate of severe cases was higher in patients with low TTV DNA load in plasma considering a threshold of 700 copies/mL. In severe patients, SARS-CoV-2 RNAemia positivity rates were higher than those in mild-moderate cases at any timepoint. When combined, TTV DNA load and SARS-CoV-2 RNAemia allowed to predict the outcome of COVID-19 infection, with a higher risk (HR=12.4) of ICU admission in patients with low TTV DNA load and positive SARS-CoV-2 RNAemia.TTV DNA load and SARS-CoV-2 RNAemia may be effective, non-invasive markers reflecting disease severity and poor outcome that could be conveniently measured in a clinical laboratory setting, as soon as COVID-19 diagnosis is made.

The US FDA has recently authorized immunocompromised people to receive a third dose of mRNA Covid-19 vaccine following the two-doses regimen to further boost protection. Unfortunately, a non-negligible proportion of people treated with immunosuppressive drugs either do not respond or show only a weak response after a third boost and should, therefore, still be considered at risk of severe Covid-19. As of June 2021, we were granted the opportunity to offer a fourth vaccine dose to French solid organ transplant recipients who still showed a weak antibody response after the third dose. In this multicenter study, we demonstrate that that the protection conferred by a fourth dose is adequate for the majority of kidney transplant recipients.

The ZEBRA (Z EBV replication activator) protein is the major transcription factor of EBV, expressed upon EBV lytic cycle activation. An increasing body of studies have highlighted the critical role of EBV lytic infection as a risk factor for lymphoproliferative disorders, such as post-transplant lymphoproliferative disease (PTLD). We studied 108 transplanted patients (17 PTLD and 91 controls), retrospectively selected from different hospitals in France and in the Netherlands. The majority of PTLD were EBV-positive diffuse large B-cell lymphomas, five patients experienced atypical PTLD forms (EBV-negative lymphomas, Hodgkin’s lymphomas, and T-cell lymphomas). Fourteen patients among the seventeen who developed a pathologically confirmed PTLD were sZEBRA positive (soluble ZEBRA, plasma level above 20 ng/mL, measured by an ELISA test). The specificity and positive predictive value (PPV) of the sZEBRA detection in plasma were 98% and 85%, respectively. Considering a positivity threshold of 20 ng/mL, the sensitivity of the sZEBRA was 82.35% and the specificity was 94.51%. The mean of the sZEBRA values in the PTLD cases were significantly higher than in the controls (p < 0.0001). The relevance of the lytic cycle and, particularly, the role of ZEBRA in lymphomagenesis is a new paradigm pertaining to the prevention and treatment strategies for PTLD. Given the high-specificity and the predictive values of this test, it now appears relevant to investigate the lytic EBV infection in transplanted patients as a prognostic biomarker.

This study examines the antibody responses to a third dose (100 μg) of the mRNA-1273 SARS-CoV-2 vaccine among kidney transplant recipients in France who had not responded to 2 doses of the vaccine.

A recent study demonstrated that a single dose of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA-based vaccine is sufficient to mount a robust immunological response in immunocompetent subjects with a previous history of coronavirus disease 2019 (COVID-19).1,2 While research has suggested that immunocompromised kidney transplant recipients (KTRs) who received mRNA-based vaccines show low immunization rates,3-5 the question as to whether this also applies to KTRs with a past history of COVID-19 remains unanswered. The aim of this study was to describe the results of immunization after one dose of the mRNA-1273 SARS-CoV-2 vaccine in KTRs who were already seropositive at baseline because of previous exposure to SARS-CoV-2.

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., ‘Laboratoire d’Excellence’ (LabEx) TRANSPLANTEX; IdEx Unistra; SFRI-STRAT’US; INSERM; European Union (EU); European Regional Development Fund; INTERREG V Program; France’s National Research Agency (Agence Nationale de Recherche; ANR); Investment for the Future Program (Programme des Investissements d’Avenir; PIA); Strasbourg’s Interdisciplinary Thematic Institute (ITI) for Precision Medicine; TRANSPLANTEX NG; ITI 2021–2028 Program of the University of Strasbourg; CNRS; Institut Universitaire de France (IUF); Fédération Hospitalo-Universitaire (FHU) OMICARE; MSD Avenir ‘Autogen’

Background and Aims IgA Nephropathy (IgAN) often recurs on kidney transplants, accounting for a significant specific kidney failure occurrence after ten years of transplantation vintage. Polyclonal anti-T-lymphocyte antibodies (PATLA) immunosuppressive induction has been shown to be associated with a lower rate of IgAN recurrence compared to basiliximab and no induction in a retrospective study. The aim of the PIRAT study was to compare an induction by PATLA versus basiliximab by the mean of a randomized controlled trial. Method Adults with biopsy-proven primary IgAN as primary cause of end stage of renal disease, first transplantation, panel reactive antibody 300mg/d during 5 years post-transplantation. Protocol biopsy at 5 years was highly recommended. Results A total of 117 patients were finally included in 13 French transplant centers, with 60 patients in the PATLA group and 57 in the basiliximab control group. Both groups were similar (median, PATLA vs. basiliximab, p>0.05 wilcoxon test) in term of sex ratio (4.45 vs 4.57), recipient age (47.9 vs. 47.7 years old), dialysis vintage (26.2 vs. 24.6 months), age at IgAN diagnosis (35.0 vs. 42.2 years old), cold ischemia (780 min vs 682 min), warm ischemia (34 vs. 36.1min), proportion of living donors (33% vs. 25%). The 5-year protocol biopsy was performed on 48% vs. 45% of patients, with overall proportion of patients evaluated by at least one biopsy of 63% vs. 66%. A trend in favor to the protection by PATLA from the occurrence of a clinico-histological recurrence was found (hazard ratio, univariate Cox model 0,35 [0.11-1.1], p=0.082). Biopsy proven histological recurrence was significantly lower after PATLA induction (HR 0.34 [0.16-0.76], p=0.0079). PATLA group experienced more infections (40 vs. 28 p=0.06), a lower number of graft losses (3 vs 9, p=0.07), a lower number of biopsy-proven acute rejections (5 vs 10, p=0.17). Similar rates of cytomegalovirus and BK virus infections were found. Conclusion PATLA for immunosuppressive induction was found protective from the recurrence of IgA deposition during the first 5 years after transplantation, compared to basiliximab. A similar trend, although not significant, was found about the clinico-histological recurrence which was the predefined primary outcome.