IntroductionCoronavirus disease 2019 (COVID-19) poses an important risk of morbidity and of mortality, in patients after solid organ transplantation. Recommendations have been issued by various transplantation societies at the national and European level to manage the immunosuppressive (IS) regimen upon admission to intensive care unit (ICU).MethodThe aim of this study was to evaluate the adequacy of IS regimen minimization strategy in kidney transplant recipients hospitalized in an ICU for severe COVID-19, in relation to the issued recommendations.ResultsThe immunosuppressive therapy was minimized in all patients, with respectively 63% and 59% of the patients meeting the local and european recommendations upon admission. During ICU stay, IS was further tapered leading to 85% (local) and 78% (european) adequacy, relative to the guidelines. The most frequent deviation was the lack of complete withdrawal of mycophenolic acid (22%). Nevertheless, the adequacy/inadequacy status was not associated to the ICU- or one-year-mortality.DiscussionIn this single-center cohort, the only variable associated with a reduction in mortality was vaccination, emphasizing that the key issue is immunization prior to infection, not restoration of immunity during ICU stay.

Pneumocystis pneumonia (PcP) remains life-threatening in kidney transplant recipients (KTR). Our study investigated risk factors one-year before PcP. We conducted a monocentric, case-control study including all KTR at the Dijon University Hospital (France) with a diagnosis of PcP between 2005 and 2022 (cases), and matched control KTR with no history of PcP (3 controls/case). Among all 1,135 KTR, 57 cases (5%) and 169 matched-controls were included. PcP was associated with 18% mortality. Compared to controls, cases were older, with a higher immunological risk, and CMV infection was more frequent in the year preceding the occurrence of PcP (23% vs. 4%; p < 0.001). As early as 1 year before PcP, lymphocyte counts were lower and serum creatinine levels were higher in cases, but immunosuppressive regimens were not significantly different. Multivariable analysis identified lymphocyte count, serum creatinine level, being treated by immunosuppressive therapy other than anti-rejection drugs, and CMV infection in the year preceding the time PcP as independently associated with the occurrence of PcP. PcP was associated with an increased risk of subsequent chronic rejection (27% vs. 3%; p = 0.001) and return to dialysis (20% vs. 3%; p = 0.002). The occurrence of CMV infection and a low lymphocyte count could redefine the indications for continuation or reinitiation of anti-Pneumocystis prophylaxis.

Background. The Banff Classification may not adequately address protocol transplant biopsies categorized as normal in patients experiencing unexplained graft function deterioration. This study seeks to employ convolutional neural networks to automate the segmentation of glomerular cells and capillaries and assess their correlation with transplant function. Methods. A total of 215 patients were categorized into three groups. In the Training cohort, glomerular cells and capillaries from 37 patients were manually annotated to train the networks. The Test cohort (24 patients) compared manual annotations vs automated predictions, while the Application cohort (154 protocol transplant biopsies) examined predicted factors in relation to kidney function and prognosis. Results. In the Test cohort, the networks recognized histological structures with Precision, Recall, F-score and Intersection Over Union exceeding 0.92, 0.85, 0.89 and 0.74, respectively. Univariate analysis revealed associations between the estimated glomerular filtration rate (eGFR) at biopsy and relative endothelial area (r = 0.19, P = .027), endothelial cell density (r = 0.20, P = .017), mean parietal epithelial cell area (r = -0.38, P < .001), parietal epithelial cell density (r = 0.29, P < .001) and mesangial cell density (r = 0.22, P = .010). Multivariate analysis retained only endothelial cell density as associated with eGFR (Beta = 0.13, P = .040). Endothelial cell density (r = -0.22, P = .010) and mean podocyte area (r = 0.21, P = .016) were linked to proteinuria at biopsy. Over 44 +/- 29 months, 25 patients (16%) reached the primary composite endpoint (dialysis initiation, or 30% eGFR sustained decline), with relative endothelial area, mean endothelial cell area and parietal epithelial cell density below medians linked to this endpoint [hazard ratios, respectively, of 2.63 (P = .048), 2.60 (P = .039) and 3.23 (P = .019)]. Conclusion. This study automated the measurement of intraglomerular cells and capillaries. Our results suggest that the precise segmentation of endothelial and epithelial cells may serve as a potential future marker for the risk of graft loss.

BACKGROUND:Although the MEST-C classification is among the best prognostic tools in immunoglobulin A nephropathy (IgAN), it has a wide interobserver variability between specialized pathologists and others. Therefore we trained and evaluated a tool using a neural network to automate the MEST-C grading. METHODS:Biopsies of patients with IgAN were divided into three independent groups: the Training cohort (n = 42) to train the network, the Test cohort (n = 66) to compare its pixel segmentation to that made by pathologists and the Application cohort (n = 88) to compare the MEST-C scores computed by the network or by pathologists. RESULTS:In the Test cohort, >73% of pixels were correctly identified by the network as M, E, S or C. In the Application cohort, the neural network area under the receiver operating characteristics curves were 0.88, 0.91, 0.88, 0.94, 0.96, 0.96 and 0.92 to predict M1, E1, S1, T1, T2, C1 and C2, respectively. The kappa coefficients between pathologists and the network assessments were substantial for E, S, T and C scores (kappa scores of 0.68, 0.79, 0.73 and 0.70, respectively) and moderate for M score (kappa score of 0.52). Network S and T scores were associated with the occurrence of the composite survival endpoint (death, dialysis, transplantation or doubling of serum creatinine) [hazard ratios 9.67 (P = .006) and 7.67 (P < .001), respectively]. CONCLUSIONS:This work highlights the possibility of automated recognition and quantification of each element of the MEST-C classification using deep learning methods.

ABSTRACT Background Interstitial inflammation and peritubular capillaritis are observed in many diseases on native and transplant kidney biopsies. A precise and automated evaluation of these histological criteria could help stratify patients’ kidney prognoses and facilitate therapeutic management. Methods We used a convolutional neural network to evaluate those criteria on kidney biopsies. A total of 423 kidney samples from various diseases were included; 83 kidney samples were used for the neural network training, 106 for comparing manual annotations on limited areas to automated predictions, and 234 to compare automated and visual gradings. Results The precision, recall and F-score for leukocyte detection were, respectively, 81%, 71% and 76%. Regarding peritubular capillaries detection the precision, recall and F-score were, respectively, 82%, 83% and 82%. There was a strong correlation between the predicted and observed grading of total inflammation, as for the grading of capillaritis (r = 0.89 and r = 0.82, respectively, all P < .0001). The areas under the receiver operating characteristics curves for the prediction of pathologists’ Banff total inflammation (ti) and peritubular capillaritis (ptc) scores were respectively all above 0.94 and 0.86. The kappa coefficients between the visual and the neural networks' scores were respectively 0.74, 0.78 and 0.68 for ti ≥1, ti ≥2 and ti ≥3, and 0.62, 0.64 and 0.79 for ptc ≥1, ptc ≥2 and ptc ≥3. In a subgroup of patients with immunoglobulin A nephropathy, the inflammation severity was highly correlated to kidney function at biopsy on univariate and multivariate analyses. Conclusion We developed a tool using deep learning that scores the total inflammation and capillaritis, demonstrating the potential of artificial intelligence in kidney pathology.

Background IgG4-related kidney disease is a major manifestation of IgG4-related disease, a systemic fibroinflammatory disorder. However, the clinical and prognostic kidney-related factors in patients with IgG4-related kidney disease are insufficiently defined. Methods We conducted an observational cohort study using data from 35 sites in two European countries. Clinical, biologic, imaging, and histopathologic data; treatment modalities; and outcomes were collected from medical records. Logistic regression was performed to identify the possible factors related to an eGFR <= 30 ml/ min per 1.73 m(2) at the last follow-up. Cox proportional hazards model was performed to assess the factors associated with the risk of relapse. Results We studied 101 adult patients with IgG4-related disease with a median follow-up of 24 (11-58) months. Of these, 87 (86%) patients were male, and the median age was 68 (57-76) years. Eighty-three (82%) patients had IgG4-related kidney disease confirmed by kidney biopsy, with all biopsies showing tubulointerstitial involvement and 16 showing glomerular lesions. Ninety (89%) patients were treated with corticosteroids, and 18 (18%) patients received rituximab as first-line therapy. At the last follow-up, the eGFR was below 30 ml/min per 1.73 m(2) in 32% of patients; 34 (34%) patients experienced a relapse, while 12 (13%) patients had died. By Cox survival analysis, the number of organs involved (hazard ratio [HR], 1.26; 95% confidence interval [CI], 1.01 to 1.55) and low C3 and C4 concentrations (HR, 2.31; 95% CI, 1.10 to 4.85) were independently associated with a higher risk of relapse, whereas first-line therapy with rituximab was protective (HR, 0.22; 95% CI, 0.06 to 0.78). At their last follow-up, 19 (19%) patients had an eGFR <= 30 ml/min per 1.73 m(2). Age (odd ratio [OR], 1.11; 95% CI, 1.03 to 1.20), peak serum creatinine (OR, 2.74; 95% CI, 1.71 to 5.47), and serum IgG4 level >= 5 g/L (OR, 4.46; 95% CI, 1.23 to 19.40) were independently predictive for severe CKD. Conclusions IgG4-related kidney disease predominantly affected middle-aged men and manifested as tubulointerstitial nephritis with potential glomerular involvement. Complement consumption and the number of organs involved were associated with a higher relapse rate, whereas first-line therapy with rituximab was associated with lower relapse rate. Patients with high serum IgG4 concentrations (>= 5 g/L) had more severe kidney disease.

Background and objectivesActivation of the complement system is involved in the pathogenesis of anti-glomerular basement membrane (anti-GBM) disease. Glomerular deposits of complement 3 (C3) are often detected on kidney biopsies. The primary objective of this study was to analyze the prognostic value of the serum C3 level and the presence of C3 glomerular deposits in patients with anti-GBM disease.MethodsWe conducted a retrospective cohort study of 150 single-positive patients with anti-GBM disease diagnosed between 1997 and 2017. Patients were categorized according to the serum C3 level (forming a low C3 (C3<1.23 g/L) and a high C3 (C3≥1.23 g/L) groups) and positivity for C3 glomerular staining (forming the C3+ and C3- groups). The main outcomes were kidney survival and patient survival.ResultsOf the 150 patients included, 89 (65%) were men. The median [interquartile range (IQR)] age was 45 [26–64]. At diagnosis, kidney involvement was characterized by a median [IQR] peak serum creatinine (SCr) level of 578 [298–977] µmol/L, and 106 (71%) patients required dialysis. Patients in the low C3 group (72 patients) had more severe kidney disease at presentation, as characterized by higher prevalences of oligoanuria, peak SCr ≥500 µmol/L (69%, vs. 53% in the high C3 group; p=0.03), nephrotic syndrome (42%, vs. 24%, respectively; p=0.02) and fibrous forms on the kidney biopsy (21%, vs. 8%, respectively; p=0.04). Similarly, we observed a negative association between the presence of C3 glomerular deposits (in 52 (41%) patients) and the prevalence of cellular forms (83%, vs. 58% in the C3- group; p=0.003) and acute tubulo-interstitial lesions (60%, vs. 36% in the C3- group; p=0.007). When considering patients not on dialysis at diagnosis, the kidney survival rate at 12 months was poorer in the C3+ group (50% [25-76], vs. 91% [78-100] in the C3- group; p=0.01), with a hazard ratio [95% confidence interval] of 5.71 [1.13-28.85] (p=0.04, after adjusting for SCr).ConclusionIn patients with anti-GBM disease, a low serum C3 level and the presence of C3 glomerular deposits were associated with more severe disease and histological kidney involvement at diagnosis. In patients not on dialysis at diagnosis, the presence of C3 deposits was associated with worse kidney survival.

Leukocyte immunoglobulin-like receptors (LILRs) are a family of inhibitory or stimulatory receptors expressed by immune cell types belonging to both myeloid and lymphoid lineage. Several members of the LILR family recognize major histocompatibility complex class I and thus play important roles in a range of clinical situations including pregnancy. Moreover, paired immunoglobulin-like receptors (PIRs), the murine orthologs of LILRs, are implicated in experimental transplant allorecognition by monocytes and contribute to the induction of donor-specific monocyte-memory. After non-self recognition, activating PIRs are transiently overexpressed at the surface of monocytes and participate in donor-specific monocyte recruitment, leading to graft rejection in vivo . In the present study, we mapped LILR expression and also their respective reported ligands at single cell level in the renal allograft and circulating cells in the context of kidney transplant rejection. Recipient-derived monocytes were shown to infiltrate the donor tissue and to differentiate into macrophages. We thus also investigate LILR expression during in vitro monocyte-to-macrophage differentiation in order to characterize the myeloid population that directly contribute to allorecognition. Altogether our results emphasize non-classical monocytes and CD68+ M1 macrophages as key players in LILRs-ligand interaction in kidney transplantation.

This study sought to identify risk factors for acute kidney injury (AKI) from pre-operative variables in a population of subjects aged over 65. Eligible patients were aged 65 years or over who underwent scheduled non-cardiac, non-ambulatory surgery. Patients with a diagnosis of AKI recorded in the hospital’s databases were considered since cases, from which 300 patients with no diagnosis of AKI, were drawn at random as controls. In total, 81 cases of post-operative AKI and 239 controls were identified. The incidence of post-operative AKI was 2.87%. Pre-operative creatinine level (p = 0.0001), a history of respiratory insufficiency (p = 0.04), prior vascular surgery (p = 0.0001) and abdominal surgery (p = 0.03) were associated with an increased risk of AKI after surgery. These four variables calculated a score and developed a nomogram for predicting occurrence of post-operative AKI. A history of renal disease was associated with increased risk of post-operative AKI, predominantly in cases of vascular or abdominal surgery.

A premature decline of thymic output in patients with chronic kidney disease (CKD) is associated with a greater risk of infectious and neoplastic events [1, 2], while its evolution after transplantation has an impact on cancer, infections and rejection occurrences [3–5]. In addition, low pre-transplant thymic function is predictive of death after transplantation [6, 7]. Recently a common intergenic variant located in the TCRA/TCRD locus was linked to interindividual variability of thymic output [8]. In the general population, GG homozygous (wild allele) carriers of the rs2204985 polymorphism had better thymopoiesis than AA homozygous (variant) patients. Our work aimed to analyse the allele impact on thymopoiesis in a cohort of CKD patients receiving a kidney transplant. This work involved 550 patients from the ORLY-EST (Influence de l'Orientation de la Re’ponse LYmphocytaire dans l'athe ’rosclerose post-trans-plantation) prospective study [5...

Background The recent COVID-19 pandemic has raised concerns about patient diagnosis and follow-up of chronically ill patients. Patients suffering from chronic illnesses, concomitantly infected by SARS-CoV-2, globally tend to have a worse prognosis and poor outcomes. Renal tropism and acute kidney injury following SARS-CoV-2 infection has recently been described in the literature, with elevated mortality rates. Furthermore, patients with pre-existing chronic kidney disease, infected by SARS-CoV-2, should be monitored carefully. Here, we report the case of a 69-year-old patient with splenic marginal zone lymphoma, suffering from longstanding chronic kidney disease following SARS-CoV-2 infection. Case presentation A 69-year-old male patient previously diagnosed with pulmonary embolism and splenic marginal zone lymphoma (Splenomegaly, Matutes 2/5, CD5 negative and CD23 positive), was admitted to the hospital with shortness of breath, fever and asthenia. A nasopharyngeal swab test was performed in addition to a CT-scan, which confirmed SARS-CoV-2 infection. Blood creatinine increased following SARS-CoV-2 infection at 130 μmol/l, with usual values at 95 μmol/l. The patient was discharged at home with rest and symptomatic medical treatment (paracetamol and hydration), then readmitted to the hospital in August 2020. A kidney biopsy was therefore conducted as blood creatinine levels were abnormally elevated. Immunodetection performed in a renal biopsy specimen confirmed co-localization of SARS-CoV2 nucleocapsid and protease 3C proteins with ACE2, Lewis x and sialyl-Lewis x antigens in proximal convoluted tubules and podocytes. Co-localization of structural and non-structural viral proteins clearly demonstrated viral replication in proximal convoluted tubules in this chronically ill patient. Additionally, we observed the co-localization of sialyl-Lewis x and ACE2 receptors in the same proximal convoluted tubules. Reverse Transcriptase-Polymerase Chain Reaction test performed on the kidney biopsy was negative, with very low Ct levels (above 40). The patient was finally readmitted to the haematology department for initiation of chemotherapy, including CHOP protocol and Rituximab. Conclusions Our case emphasizes on the importance of monitoring kidney function in immunosuppressed patients and patients suffering from cancer following SARS-CoV-2 infection, through histological screening. Further studies will be required to decipher the mechanisms underlying chronic kidney disease and the putative role of sialyl-Lewis x and HBGA during SARS-CoV-2 infection.

Background and objectives The prognosis of patients undergoing kidney tumor resection or kidney donation is linked to many histologic criteria. These criteria notably include glomerular density, glomerular volume, vascular luminal stenosis, and severity of interstitial fibrosis/tubular atrophy. Automated measurements through a deep-learning approach could save time and provide more precise data. This work aimed to develop a free tool to automatically obtain kidney histologic prognostic features. Design, setting, participants, & measurements In total, 241 samples of healthy kidney tissue were split into three independent cohorts. The “Training” cohort ( n =65) was used to train two convolutional neural networks: one to detect the cortex and a second to segment the kidney structures. The “Test” cohort ( n =50) assessed their performance by comparing manually outlined regions of interest to predicted ones. The “Application” cohort ( n =126) compared prognostic histologic data obtained manually or through the algorithm on the basis of the combination of the two convolutional neural networks. Results In the Test cohort, the networks isolated the cortex and segmented the elements of interest with good performances (>90% of the cortex, healthy tubules, glomeruli, and even globally sclerotic glomeruli were detected). In the Application cohort, the expected and predicted prognostic data were significantly correlated. The correlation coefficients r were 0.85 for glomerular volume, 0.51 for glomerular density, 0.75 for interstitial fibrosis, 0.71 for tubular atrophy, and 0.73 for vascular intimal thickness, respectively. The algorithm had a good ability to predict significant (>25%) tubular atrophy and interstitial fibrosis level (receiver operator characteristic curve with an area under the curve, 0.92 and 0.91, respectively) or a significant vascular luminal stenosis (>50%) (area under the curve, 0.85). Conclusion This freely available tool enables the automated segmentation of kidney tissue to obtain prognostic histologic data in a fast, objective, reliable, and reproducible way.

Coronavirus disease 2019 (COVID-19) is associated with high morbidity and mortality in patients on maintenance haemodialysis (HD) [1]. Thus dialysis patients were prioritized for anti-COVID vaccination [2]. However, the ideal vaccination schedule remains unknown in this population [3], as patients suffering from chronic kidney disease have an altered immune response [4], with a diminished vaccine response to the hepatitis B virus [5] and flu vaccines [6]. In this work we sought to evaluate the humoral response to the BNT162b2 anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine and its associated factors in a French cohort of HD patients. In this monocentric observational study, 58 HD patients who received two doses of the BNT162b2 (Pfizer-BioNTech) vaccine were included. Vaccines were injected at the start of HD sessions, with 21 days between the first and second dose. Among the patients,...

End-stage renal disease (ESRD) patients exhibit clinical features of premature ageing, including frailty, cardiovascular disease, and muscle wasting. Accelerated ageing also concerns the immune system. Patients with ESRD have both immune senescence and chronic inflammation that are resumed in the so-called inflammaging syndrome. Immune senescence is particularly characterised by premature loss of thymic function that is associated with hyporesponsiveness to vaccines, susceptibility to infections, and death. ESRD-related chronic inflammation has multiple causes and participates to accelerated cardiovascular disease. Although, both characterisation of immune senescence and its consequences are relatively well-known, mechanisms are more uncertain. However, prevention of immune senescence/inflammation or/and rejuvenation of the immune system are major goal to ameliorate clinical outcomes of ESRD patients.

Clinical Practice Points Oxaliplatin is recommended for the treatment of stage II and III colorectal cancer. Most reported adverse effects for oxaliplatin are mild and include paresthesia (2%-12%), diarrhea (11.5%-19%), and vomiting (4.1%-6%). Severe anemia, thrombocytopenia, or Evans syndrome are rarely reported adverse effects for oxaliplatin. To our knowledge, this is the first reported case of Evans syndrome complicated by severe acute tubular necrosis associated with oxaliplatin-induced antibodies and probable nonimmunologic protein adsorption detected with the immune complex method. (C) 2019 Elsevier Inc. All rights reserved.

L’immunosénescence participe au développement des maladies liées à l’âge (infections, maladies cardiovasculaires et cancers). Les patients insuffisants rénaux chroniques terminaux présentent une mortalité prématurée par rapport à la population générale, secondaire à une plus grande susceptibilité à la survenue d’infections, d’événements cardiovasculaires et de cancers, pathologies habituellement rencontrées chez les personnes âgées et associées à l’immunosénescence. L’insuffisance rénale chronique engendre un vieillissement prématuré du compartiment lymphocytaire T, notamment concernant la fonction thymique qui joue un rôle clé dans la survenue précoce de pathologies du vieillissement chez ces patients insuffisants rénaux chroniques. Le niveau d’immunosénescence influence également le devenir en transplantation rénale, notamment les risques de survenue de rejet aigu et d’infections. Une réversion partielle de l’immunosénescence pré-transplantation est observée pour certains patients transplantés rénaux. En conclusion, afin de limiter la morbi-mortalité des patients insuffisants rénaux chroniques dont l’incidence augmente tous les ans, la meilleure connaissance de l’immunosénescence induite par l’urémie ouvre la voie à des études cliniques et des pistes thérapeutiques innovantes. Les approches thérapeutiques de réversion et de prévention de l’immunosénescence feront partie de la prise en charge des patients insuffisants rénaux chroniques dans l’avenir.

Introduction: Renal transplant recipients have a high peri-operative risk for cardiovascular events. The post-transplantation period also carries a risk of myocardial infarction (MI). Coronary artery disease (CAD) is a leading cause of death in these patients. We aimed to assess the risk of MI, the specific morbidity profile of MI after transplantation as well as the long-term prognosis after MI in renal transplantation (RT) patients regarding cardiovascular (CV) death and all-cause death. Methods: From a French national medical information database, all of the patients seen in French hospitals in 2013 with at least 5-years follow-up were retrospectively identified and patients without transplantation but with previous dialysis at baseline were excluded. There were 17,526 patients with RT and 3,288,857 with no RT. Results: Among these patients, 1020 in the RT group (5.8%), and 93,320 in the non-RT group (2.8%) suffered acute MI during a median follow-up of 5.4 years. After multivariable adjustment, risk of MI was higher in RT patients than in non-RT patients (HR 1.45, IC 95% 1.35–1.55). The mean age was 59.5 years for transplant patients with MI, and 70.6 years for the reference population with MI (p < 0.0001). MI patients with RT (vs. non RT patients) were more likely to have hypertension, diabetes dyslipidemia, and peripheral artery disease (76.0% vs. 48.1%, 38.7% vs. 25.2%, 33.2% vs. 23.2%, and 31.2% vs. 17.3%, respectively, p < 0.0001). Incidence of non ST-elevation MI (NSTEMI) was higher in RT patients while incidence of ST-elevation MI (STEMI) was higher in patients without RT. In unadjusted analysis, risk of all-cause death and CV death within the first month after MI were higher in patients without RT (18% vs. 11.1% p < 0.0001 and 12.3% vs. 7.8%, p < 0.0001, respectively). However, multivariable analysis indicated that risk of all-cause death was higher in patients with RT than in those with no RT (adjusted HR 1.15 IC 95% 1.03–1.28). Conclusions: MI is not an uncommon complication after RT (incidence of around 5.8% after 5 years). RT is independently associated with a 45% higher risk of MI than in patients without RT, with a predominance of NSTEMI. MI in patients with RT is independently associated with a 15% higher risk of all-cause death than that in patients with MI and no RT.

IgG4 disease is a systemic fibroinflammatory disorder that may affect virtually any organ. IgG4-related kidney disease (IgG4-RKD) is a major manifestation, occurring in almost one third of patient. The present study addresses the diagnosis, management and outcome of French patients with IgG4-RKD. We conducted a retrospective observational study including patients with renal impairment due to IgG4-RKD from 32 centers. Clinical, biological, and imaging data, as well as management modalities and outcome, were retrieved from medical records. 74 patients, 64 males and 10 females, were diagnosed with IgG4-RKD between 1997 and 2019 and were included in the present study. The mean age at diagnosis was 65.2 ± 15-year-old. Renal involvement was present at diagnosis in 63% of cases. Nine (12%) patients had isolated renal involvement, whereas extra-renal involvement included retroperitoneal fibrosis (20%), auto-immune pancreatitis (49%), cholangitis (27%), and lung disease (22%). Renal imaging lesions were observed in 48 (64%) patients, and included renal hypertrophy, patchy lesions and pseudo-tumor solitary renal lesion. PET-CT scan was performed in 47 (65%) patients and showed hypermetabolic renal lesion(s) in 36% of cases. The presence of extra-renal hypermetabolic lesions was observed in 35 cases (74%). 43 %, 25% and 14% of patients presented with AKI, AKI-on-CKD, and isolated CKD, respectively. The mean serum creatinine level at diagnosis was 244 ± 140 µmol/L, corresponding to an eGFR of 69 ± 22ml/min/1.73m. Urinary sediment was most often bland. Mean urine protein-to-creatinine ratio was 1.27 g/g. of note, 26% of patients had more than 1 g/g. 82% of patients underwent a kidney biopsy showing tubulointerstitial involvement in all cases, 12 (16%) had additional glomerular involvement, mainly membranous nephropathy. The major additional laboratory abnormalities included polyclonal hypergammaglobulinemia, and increased serum IgG4 increase in 83% and 86%, respectively. Complement levels were decreased in 27 (37%) patients. Two patients were lost for follow-up and 69 patients were treated with corticosteroid therapy in 66 (89%) patients and 10 received Rituximab as first line therapy. The mean duration of follow-up was 28.8 ± 30 months. During follow-up, 22 (30%) patients relapsed, while 45 (62%) patients had persistent CKD at last follow-up, with a mean eGFR of 47±27 ml/min/1.73m. Seven (9%) patients progressed to ESRD and 7 died. A significant response was achieved in 46 (62%) patients. Patients who received steroids higher than 0.5mg/kg/day had lower serum IgG4 levels (1.8 g/l versus 5.7 g/l, p=0.007) at last follow up but there was no significant difference observed in terms of renal function between the two groups (45.5 vs 48.8 ml/min/1.73m, p= 0.72). By univariate analysis, predictors of relapse were low C3 or C4 serum level (p=0.01), ANCA positivity (p= 0.02), renal radiological lesions (p=0.05). At last follow-up the eGFR was worse in patients with a serum creatinine diagnosis greater than 300 µmol/L (30.25 vs 57 ml/min/1.73m p=0.0001) and more progressed to ESRD (p=0.03). IgG4-RKD has been recently described and may affect middle-aged males. The disease presents as tubulointerstitial nephritis with glomerular involvement in 16% of cases. Disease response to corticosteroid therapy is favorable but is characterized by a high rate of relapses and a significant risk of persistent CKD in the majority of patient. Risk of ESRD and death in almost 20% of patients.

The histologic assessment of the nontumoral kidney parenchyma is recommended in kidney cancer management. This analysis allows an estimation of CKD risk in patients with favorable cancer-related prognosis and whose survival is correlated with progression toward ESKD.1 Denic et al.2 identify several predictive features of CKD progression by analyzing large wedges of nontumoral kidney parenchyma among patients with kidney cancer. Other than larger glomerular size and nephrosclerosis, the authors focused on the larger cortex per glomerulus as an independent predictor of progressive CKD. This observation emphasizes the clinical relevance of glomerular density as a witness of the total nephron mass. However, the significant inter-individual variability in kidney size requires to relate the glomerular density to the cortical volume, resulting in an estimation of the total nephron number, which in our opinion is a more accurate marker of kidney health than the glomerular density alone. The initial assessment of patients with kidney cancer generally includes a pre-treatment abdominal computed tomography, which allows us to estimate the total cortical volume of the nontumoral kidney. In patients without underlying kidney disease, the cortical volume of the healthy kidney combined with the glomerular density estimation assessed in the nontumoral parenchyma provides an accurate evaluation of the total nephron number of the concerned kidney.3 This method is on the basis of the hypothesis of a homogeneous repartition of the glomeruli between two similar-sized kidneys (not taking the tumor into account). The total nephron number is probably a crucial determinant of CKD progression after the removal of half of the nephron mass, reflecting the adaptation capacities of the remaining kidney due to the increased filtered load per glomerulus.4 Considering its relevance, the total nephron number should be more commonly measured to predict progressive CKD. Disclosures J. Rebibou reports other interests/relationships with French Society of Nephrology Dialysis and Transplantation and ISN. All remaining authors have nothing to disclose. Funding None.