Atypical Anti-Glomerular Basement Membrane Nephritis: A Case Series From the French Nephropathology Group.

RATIONALE & OBJECTIVE: Atypical anti-glomerular basement membrane (GBM) nephritis is characterized by a bright linear immunoglobulin staining along the GBM by immunofluorescence without a diffuse crescentic glomerulonephritis nor serum anti-GBM antibodies by conventional enzyme-linked immunosorbent assay (ELISA). We characterized a series of patients with atypical anti-GBM disease. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Patients identified by the French Nephropathology Group as having atypical anti-GBM nephritis between 2003 and 2022. FINDINGS: Among 38 potential cases, 25 were included, of whom 14 (56%) were female and 23 (92%) had hematuria. The median serum creatinine at diagnosis was 150 (IQR, 102-203) µmol/L and median urine protein-creatinine ratio (UPCR) was 2.4 (IQR, 1.3-5.2) g/g. Nine patients (36%) had endocapillary proliferative glomerulonephritis (GN), 4 (16%) had mesangial proliferative GN, 4 (16%) had membranoproliferative GN, 2 (8%) had pure and focal crescentic GN, 1 (4%) had focal segmental glomerulosclerosis, and 5 had glomeruli that were unremarkable on histopathology. Nine patients (36%) had crescents, involving a median of 9% of glomeruli. Bright linear staining for IgG was seen in 22 cases (88%) and for IgA in 3 cases (12%). The 9 patients (38%) who had a monotypic staining pattern tended to be older with less proteinuria and rarely had crescents. Kidney survival rate at 1 year was 83% and did not appear to be associated with the light chain restriction. LIMITATIONS: Retrospective case series with a limited number of biopsies including electron microscopy. CONCLUSIONS: Compared with typical anti-GBM disease, atypical anti-GBM nephritis frequently presents with an endocapillary or mesangial proliferative glomerulonephritis pattern and appears to have a slower disease progression. Further studies are needed to fully characterize its pathophysiology and associated clinical outcomes. PLAIN-LANGUAGE SUMMARY: Atypical anti-glomerular basement membrane (GBM) nephritis is characterized histologically by bright linear immunoglobulin staining along the GBM without diffuse crescentic glomerulonephritis or circulating anti-GBM antibodies. We report a case series of 25 atypical cases of anti-GBM nephritis in collaboration with the French Nephropathology Group. Compared with typical anti-GBM disease, we observed a slower disease progression. Patients frequently presented with heavy proteinuria and commonly had evidence of endocapillary or mesangial proliferative glomerulonephritis. About half of the patients displayed a monotypic immune staining pattern; they tended to be older, with less proteinuria, and commonly without glomerular crescents in biopsy specimens. No concomitant circulating monoclonal gammopathy was detected. Further studies are needed to fully characterize its pathophysiology and associated clinical outcomes.

Kidney Transplantation in Patients With AA Amyloidosis: Outcomes in a French Multicenter Cohort.

RATIONALE & OBJECTIVE: Outcomes of kidney transplantation for patients with renal AA amyloidosis are uncertain, with reports of poor survival and high rates of disease recurrence. However, the data are inconclusive and mostly based on studies from the early 2000s and earlier. STUDY DESIGN: Retrospective multicenter cohort study. SETTING & PARTICIPANTS: We searched the French national transplant database to identify all patients with renal AA amyloidosis who underwent kidney transplantation between 2008 and 2018. EXPOSURES: Age, cause of amyloidosis, use of biotherapies, and C-reactive protein levels. OUTCOMES: Outcomes were all-cause mortality and allograft loss. We also reported amyloidosis allograft recurrence, occurrence of acute rejection episodes, as well as infectious, cardiovascular, and neoplastic disease events. ANALYTICAL APPROACH: Kaplan-Meier estimator for mortality and cumulative incidence function method for allograft loss. Factors associated with patient and allograft survival were investigated using a Cox proportional hazards model and a cause-specific hazards model, respectively. RESULTS: 86 patients who received kidney transplants for AA amyloidosis at 26 French centers were included. The median age was 49.4 years (IQR, 39.7-61.1). The main cause of amyloidosis was familial Mediterranean fever (37 cases; 43%). 16 (18.6%) patients received biotherapy after transplantation. Patient survival rates were 94.0% (95% CI, 89.1-99.2) at 1 year and 85.5% (77.8-94.0) at 5 years after transplantation. Cumulative incidences of allograft loss were 10.5% (4.0-17.0) at 1 year and 13.0% (5.8-20.1) at 5 years after transplantation. Histologically proven AA amyloidosis recurrence occurred in 5 transplants (5.8%). An infection requiring hospitalization developed in 55.8% of cases, and there was a 27.9% incidence of acute allograft rejection. Multivariable analysis showed that C-reactive protein concentration at the time of transplantation was associated with patient survival (HR, 1.01; 95% CI, 1.00-1.02; P=0.01) and allograft survival (HR, 1.68; 95% CI, 1.10-2.57; P=0.02). LIMITATIONS: The study lacked a control group, and the effect of biotherapies on transplantation outcomes could not be explored. CONCLUSIONS: This relatively contemporary cohort of patients who received a kidney transplant for AA amyloidosis experienced favorable rates of survival and lower recurrence rates than previously reported. These data support the practice of treating these patients with kidney transplantation for end-stage kidney disease. PLAIN-LANGUAGE SUMMARY: AA amyloidosis is a severe and rare disease. Kidney involvement is frequent and leads to end-stage kidney disease. Because of the involvement of other organs, these patients are often frail, which has raised concerns about their suitability for kidney transplantation. We reviewed all patients with AA amyloidosis nephropathy who underwent kidney transplantation in France in the recent era (2008-2018) and found that the outcomes after kidney transplantation were favorable, with 85.5% of patients still alive 5 years after transplantation, a survival rate that is comparable to the outcomes of patients receiving a transplant for other forms of kidney diseases. Recurrence of amyloidosis in the transplanted kidney was infrequent (5.8%). These data support the practice of kidney transplantation for patients with AA amyloidosis who experience kidney failure.

Prophylactic treatment of FSGS recurrence in patients who relapsed in a previous kidney graft.

BACKGROUND AND HYPOTHESIS: Recurrence of focal segmental glomerulosclerosis (FSGS) is common after kidney transplantation and is classically associated with a significant decrease in graft survival. A major risk factor is a prior history of FSGS recurrence on a previous graft. This analysis reports the impact of a prophylactic treatment of FSGS recurrence in very high-risk patients who experienced a recurrence on a previous graft. METHODS: We performed a retrospective multicentre observational study in 25 French transplantation centres. The inclusion criteria were patients aged more than 18 years who had undergone kidney transplant between December 31, 2004, and December 31, 2020, and who had a history of FSGS recurrence on a previous graft. RESULTS: We identified 66 patients: 40 received prophylactic treatment (PT+), including intravenous cyclosporine and/or rituximab and/or plasmapheresis, and 26 did not receive any prophylactic treatment (PT-). The time to progression to end-stage kidney disease was similar between groups. The PT + group was younger at FSGS diagnosis and at the time of kidney retransplantation and lost their previous graft faster. The overall recurrence rate was 72.7% (76.9% in the PT- group and 70.0% in the PT + group, P = 0.54). At least partial remission was achieved in 87.5% of patients. The 5-year graft survival was 67.7% (95% CI: 53.4 to 78.4%): 65.1% (95%CI: 48.7 to 77.4%) in patients with FSGS recurrence vs. 77.3% (95% CI: 43.8 to 92.3%) in patients without recurrence (P = 0.48). CONCLUSION: Our study suggests that prophylactic treatment should not be used routinely in patients receiving a second transplantation after recurrence of FSGS on a previous graft. The recurrence rate is high regardless of the use of prophylactic treatment. However, the 5-year graft survival remains satisfactory.

The spectrum of glomerular and vascular kidney pathology associated with myeloproliferative neoplasms.

A high prevalence of chronic kidney disease (CKD) occurs in patients with myeloproliferative neoplasms (MPN). However, MPN-related glomerulopathy (MPN-RG) may not account for the entirety of CKD risk in this population. The systemic vasculopathy encountered in these patients raises the hypothesis that vascular nephrosclerosis may be a common pattern of injury in patients with MPN and with CKD. In an exhaustive, retrospective, multicenter study of MPN kidney biopsies in four different pathology departments, we now describe glomerular and vascular lesions and establish clinicopathologic correlations. Our study encompassed 47 patients with MPN who underwent a kidney biopsy that included 16 patients with chronic myeloid leukemia (CML) and 31 patients with non-CML MPN. Fourteen cases met a proposed definition of MPN-RG based on mesangial sclerosis and hypercellularity, as well as glomerular thrombotic microangiopathy. MPN-RG was significantly associated with both myelofibrosis and poorer kidney survival. Thirty-three patients had moderate-to-severe arteriosclerosis while 39 patients had moderate-to-severe arteriolar hyalinosis. Multivariable models that included 188 adult native kidney biopsies as controls revealed an association between MPN and chronic kidney vascular damage, which was independent of established risk factors such as age, diabetes mellitus and hypertension. Therefore, MPN-RG is associated with myelofibrosis and has a poor kidney prognosis. Thus, our findings suggest that the kidney vasculature is a target during MPN-associated vasculopathy and establish a new link between MPN and CKD. Hence, these results may raise new hypotheses regarding the pathophysiology of vascular nephrosclerosis in the general population.

Glomerular diseases in pregnancy: pragmatic recommendations for clinical management.

Our understanding of the various aspects of pregnancy in women with kidney diseases has significantly improved in the last decades. Nevertheless, little is known about specific kidney diseases. Glomerular diseases are not only a frequent cause of chronic kidney disease in young women, but combine many challenges in pregnancy: immunologic diseases, hypertension, proteinuria, and kidney tissue damage. An international working group undertook the review of available current literature and elicited expert opinions on glomerular diseases in pregnancy with the aim to provide pragmatic information for nephrologists according to the present state-of-the-art knowledge. This work also highlights areas of clinical uncertainty and emphasizes the need for further collaborative studies to improve maternal and fetal health.

C3 Glomerulopathy With Concurrent Thrombotic Microangiopathy: Clinical and Immunological Features.

RATIONALE & OBJECTIVE: C3 glomerulopathy (C3GN) and atypical hemolytic uremic syndrome (aHUS) are 2 distinct rare kidney diseases caused by dysregulation of the alternative complement pathway. Patients with C3GN and concurrent kidney lesions of thrombotic microangiopathy (TMA) have been rarely reported. We characterized the clinical features and underlying immunological abnormalities in these patients. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: Patients with C3GN and concomitant TMA lesions on biopsy registered from 2009 to 2019 in the French National Registry of C3GN. FINDINGS: Among 278 registered patients with C3GN, 16 (6%) had biopsy-proven glomerular and/or vascular TMA lesions. Their median age at diagnosis was 39 years (range, 7-76), and 59% were female. Fourteen of the 16 patients (88%) had an estimated glomerular filtration rate of<30mL/min/1.73m2 and 3 of 16 (19%) required dialysis. Twelve of the 14 evaluated patients (86%) showed evidence of mechanical hemolysis. Fifty percent of the patients had low C3 levels. Six of the 14 evaluated patients had a rare variant in complement genes, and 4 of the 16 patients (25%) had monoclonal gammopathy. Among the 16 patients, 10 (63%) received eculizumab, 5 (31%) received immunosuppressive therapy, and 4 (25%) received clone-targeted chemotherapy. Median kidney survival was 49 months. LIMITATIONS: Small retrospective case series with a limited number of biopsies including electron microscopy. CONCLUSIONS: Concomitant C3GN and TMA is extremely rare and is associated with poor kidney outcomes. Genetic or acquired abnormalities of the alternative complement pathway are common as is the presence of monoclonal gammopathy, which may inform the selection of treatment approaches.

Social deprivation and kidney failure due to an undiagnosed nephropathy.

BACKGROUND: In France, kidney diseases of undetermined origin account for 5%-20% of all causes of end-stage kidney disease. We investigated the impact of social disadvantage on the lack of aetiological diagnosis of nephropathies. METHODS: Data from patients who started dialysis in France between 1 January 2017 and 30 June 2018 were extracted from the French Renal Epidemiology and Information Network registry. The social deprivation of each individual was estimated by the European Deprivation Index (EDI) defined by the patient's address. Logistic regression was used to perform mediation analysis to study the potential association between social deprivation and unknown nephropathy. RESULTS: Of the 7218 patients included, 1263 (17.5%) had unknown kidney disease. A total of 394 (31.4%) patients in the unknown kidney disease belonged to the most deprived quintile of the EDI [fifth quintile (Q5)], vs 1636 (27.5%) patients in the known kidney disease group. In the multivariate analysis, unknown kidney disease was associated with Q5 (odds ratio 1.40, 95% confidence interval 1.12-1.74, P = .003). Mediation analysis did not identify any variables (e.g. obesity, initiation of dialysis in emergency, number of visits to the general practitioner and nephrologist before initiation of dialysis, date of first nephrology consultation) that mediated the association between social deprivation and nephropathy of unknown origin. CONCLUSIONS: Our results show that, compared with nondeprived subjects, individuals experiencing social deprivation have a higher risk of unknown nephropathy at dialysis initiation. However, mediation analysis did not identify any variables that explained the association between social deprivation and nephropathy of unknown origin.

Pathological spectrum of hereditary transthyretin renal amyloidosis and clinicopathologic correlation: a French observational study.

BACKGROUND: Cardiac and neurological involvements are the main clinical features of hereditary transthyretin (ATTRv) amyloidosis. Few data are available about ATTRv amyloid nephropathy (ATTRvN). METHODS: We retrospectively included 30 patients with biopsy-proven ATTRvN [V30M (26/30) including two domino liver recipients, S77Y (2/30), V122I (1/30) and S50R (1/30) variants] from two French reference centers. We described the pathological features by comparing amyloid deposits distribution to patients with AL or AA amyloidosis, and sought to determine clinicopathological correlation with known disease-modifying factors such as TTR variant, gender and age at diagnosis. RESULTS: In comparison with AL and AA amyloidosis, ATTRv patients had similar glomerular, arteriolar and arterial amyloid deposits, but more cortical and medullary tubulointerstitial (33%, 44%, 77%, P = .03) involvement. While the presence of glomerular deposits is associated with the range of proteinuria, some patients with abundant glomerular ATTRv amyloidosis had no significant proteinuria. V30M patients had more glomerular (100% and 25%, odds ratio = 114, 95% confidence interval 3.85-3395.00, P = .001) deposits, and higher estimated glomerular filtration rate [50 (interquartile range 44-82) and 27 (interquartile range 6-31) mL/min/1.73 m², P = .004] than non-V30M patients. We did not find difference in amyloid deposition according to gender or age at diagnosis. CONCLUSION: ATTRvN affects all kidney compartments, but compared with AL/AA amyloidosis, ATTRvN seems to involve more frequently tubulointerstitial areas. V30M patients represents the dominant face of the disease with a higher risk of glomerular/arteriolar involvement. ATTRvN should thus be considered in patients, and potential relatives, with ATTRv amyloidosis and kidney dysfunction, regardless of proteinuria level.

Efficacy and safety of methylprednisolone pulse followed by oral prednisone vs. oral prednisone alone in sarcoidosis tubulointerstitial nephritis: a randomized, open-label, controlled clinical trial.

BACKGROUND: We determine the benefit of pulsed methylprednisolone for improving kidney function in patients with sarcoidosis tubulointerstitial nephritis. METHODS: We conducted a multicenter, prospective, randomized, open-label, controlled trial in patients with biopsy-proven acute tubulointerstitial nephritis caused by sarcoidosis at 21 sites in France. Patients were randomly assigned to receive a methylprednisolone pulse 15 mg/kg/day for 3 days, then oral prednisone (MP group) or oral prednisone 1 mg/kg/day alone (PRD group). The primary end point was a positive response at 3 months, defined as a doubling of estimated glomerular filtration rate (eGFR) compared with the eGFR before randomization. RESULTS: We randomized 40 participants. Baseline eGFR before PRD was 22 mL/min/1.73m2 {interquartile range [IQR], 16-44} and before MP was 25 mL/min/1.73m2 (IQR, 22-36) (P = .3). The two groups did not differ in underlying pathological lesions, including mean percentage of interstitial fibrosis and intensity of interstitial infiltrate. In the intent-to-treat population, the median eGFR at 3 months did not significantly differ between the PRD and MP groups: 45 (IQR, 34-74) and 46 (IQR, 39-65) mL/min/1.73m2. The primary end point at 3 months was achieved in 16 of 20 (80%) PRD patients and 10 of 20 (50%) MP patients (P = .0467). The eGFR was similar between the two groups after 1, 3, 6, and 12 months of treatment. For both groups, eGFR at 1 month was strongly correlated with eGFR at 12 months (P < .0001). The two groups did not differ in severe adverse events. CONCLUSION: Compared with a standard oral steroid regimen, intravenous MP may have no supplemental benefit for renal function in patients with tubulointerstitial nephritis caused by sarcoidosis.Trial Registration: ClinicalTrials.gov: NCT01652417; EudraCT: 2012-000149-11.

Kidney Histopathology Can Predict Kidney Function in ANCA-Associated Vasculitides with Acute Kidney Injury Treated with Plasma Exchanges.

BACKGROUND: Data from the PEXIVAS trial challenged the role of plasma exchange (PLEX) in ANCA-associated vasculitides (AAV). We aimed to describe kidney biopsy from patients with AAV treated with PLEX, evaluate whether histopathologic findings could predict kidney function, and identify which patients would most benefit from PLEX. METHODS: We performed a multicenter, retrospective study on 188 patients with AAV and AKI treated with PLEX and 237 not treated with PLEX. The primary outcome was mortality or KRT at 12 months (M12). RESULTS: No significant benefit of PLEX for the primary outcome was found. To identify patients benefitting from PLEX, we developed a model predicting the average treatment effect of PLEX for an individual depending on covariables. Using the prediction model, 223 patients had a better predicted outcome with PLEX than without PLEX, and 177 of them had >5% increased predicted probability with PLEX compared with without PLEX of being alive and free from KRT at M12, which defined the PLEX-recommended group. Risk difference for death or KRT at M12 was significantly lower with PLEX in the PLEX-recommended group (-15.9%; 95% CI, -29.4 to -2.5) compared with the PLEX not recommended group (-4.8%; 95% CI, 14.9 to 5.3). Microscopic polyangiitis, MPO-ANCA, higher serum creatinine, crescentic and sclerotic classes, and higher Brix score were more frequent in the PLEX-recommended group. An easy to use score identified patients who would benefit from PLEX. The average treatment effect of PLEX for those with recommended treatment corresponded to an absolute risk reduction for death or KRT at M12 of 24.6%. CONCLUSIONS: PLEX was not associated with a better primary outcome in the whole study population, but we identified a subset of patients who could benefit from PLEX. However, these findings must be validated before utilized in clinical decision making.

Proteomics of Plasma and Plasma-Treated Podocytes: Application to Focal and Segmental Glomerulosclerosis.

Focal and segmental glomerulosclerosis (FSGS) is a severe form of idiopathic nephrotic syndrome (INS), a glomerulopathy of presumably immune origin that is attributed to extrarenal pathogenic circulating factors. The recurrence of FSGS (rFSGS) after transplant occurs in 30% to 50% of cases. The direct analysis of patient plasma proteome has scarcely been addressed to date, mainly due to the methodological difficulties associated with plasma complexity and dynamic range. In this study, first, we compared different methods of plasma preparation, second, we compared the plasma proteomes of rFSGS and controls using two preparation methods, and third, we analyzed the early proximal signaling events in podocytes subjected to patient plasma, through a combination of phosphoproteomics and lipid-raft proteomics (raftomics). By combining immunodepletion and high pH fractionation, we performed a differential proteomic analysis of soluble plasma proteins and of extracellular vesicles (EV) obtained from healthy controls, non-INS patient controls, and rFSGS patients (n = 4). In both the soluble- and the EV-protein sets from the rFSGS patients, we found a statistically significant increase in a cluster of proteins involved in neutrophil degranulation. A group of lipid-binding proteins, generally associated with lipoproteins, was found to be decreased in the soluble set from the rFSGS patients. In addition, three amino acid transporters involved in mTORC1 activation were found to be significantly increased in the EV from the rFSGS. Next, we incubated human podocytes for 30 min with 10% plasma from both groups of patients. The phosphoproteomics and raftomics of the podocytes revealed profound differences in the proteins involved in the mTOR pathway, in autophagy, and in cytoskeleton organization. We analyzed the correlation between the abundance of plasma and plasma-regulated podocyte proteins. The observed changes highlight some of the mechanisms involved in FSGS recurrence and could be used as specific early markers of circulating-factor activity in podocytes.

Optical coherence tomography angiography analysis of changes in the retina and the choroid after hemodialysis for end stage kidney disease.

PURPOSE: To study effects of hemodialysis (HD) on retinal and choroidal vasculature in patients with end-stage kidney disease (ESKD) using optical coherence tomography angiography (OCTA). METHODS: In this prospective study, we investigated eyes of patients undergoing hemodialysis for ESKD from Mondor University Hospital. Only one eye/patient was considered. Subfoveal choroidal thickness (SCT) was measured on enhanced-depth imaging optical coherence tomography (EDI-OCT) before and after the hemodialysis session. OCTA was used to extract retinal vascular density (superficial and deep capillary plexus, SCP, DCP) and choriocapillaris non-perfusion. Clinical, demographic and biological parameters (Blood B-Nitric Peptid rate prior to HD session) were reviewed. RESULTS: Twenty patients (mean age 53.2 ± 13.6 years, 10 males and 10 females) were included in this prospective study. SCT significantly decreased after the HD session (234.3 ± 56.14 µm before HD to 211.9 ± 60.79 µm after hemodialysis (Wilcoxon signed-rank test, p = 0.003)). Non-perfusion in the choriocapillaris significantly increased after HD (41.65 ± 3.58 before HD, 42.95 ± 3.19 after HD, p = 0.036) while no significant modification of the vascular density was observed in the retinal vasculature (SCP, DCP) around the macular zone or the optic nerve. An increased plasma B-Nitric Peptide (BNP) level prior to the onset of the HD session was significantly correlated with the decrease of the SCT (r = 0.45, p = 0.043). CONCLUSION: Hemodialysis in patients with ESKD is associated with a significant decrease in SCT and an increase in non-perfusion in the choriocapillaris on OCTA. A High BNP level prior to the onset of the hemodialysis appears to be correlated with the decrease in SCT.

ANCA-Negative Pauci-immune Necrotizing Glomerulonephritis: A Case Series and a New Clinical Classification.

RATIONALE & OBJECTIVE: Pauci-immune necrotizing glomerulonephritis (PING) is usually associated with the presence of antineutrophil cytoplasmic antibodies (ANCA). However, a minority (2%-3%) of patients with PING do not have detectable ANCA. We assessed the clinical spectrum and outcome of patients with ANCA-negative PING. STUDY DESIGN: Case series. SETTING & PARTICIPANTS: 74 patients with ANCA-negative PING diagnosed in 19 French nephrology centers between August 2006 and December 2018 were included in the series. Patients' medical files were reviewed, and kidney biopsies were centrally reexamined by pathologists who were masked to the diagnosis. FINDINGS: Median age at diagnosis was 69 (IQR, 61-76) years. The clinical and pathological features were remarkable for a high frequency of extrarenal manifestations (54%), nephrotic syndrome (32%), and endocapillary hypercellularity (31%). Three main subtypes of ANCA-negative PING were observed: infection-associated (n=9[12%]), malignancy-associated (n=6[8%]), and primary (n=57[77%]). For patients with primary PING, induction treatment included mainly corticosteroids (n=56[98%]), cyclophosphamide (n=37[65%]), and rituximab (n=5[9%]). Maintenance treatment consisted mainly of corticosteroids (n=42[74%]), azathioprine (n=18[32%]), and mycophenolate mofetil (n=11[19%]). After a median follow-up period of 28 months, 28 (38%) patients had died and 20 (27%) developed kidney failure (estimated glomerular filtration rate<15mL/min/1.73m2). Eleven (21%) patients (9 with primary and 2 with malignancy-associated PING) relapsed. LIMITATIONS: Retrospective study and limited number of patients; electron microscopy was not performed to confirm the absence of glomerular immune deposits. CONCLUSIONS: Within the spectrum of ANCA-negative PING, infection and malignancy-associated forms represent a distinct clinical subset. This new clinical classification may inform the management of ANCA-negative PING, which remains a severe form of vasculitis with high morbidity and mortality rates despite immunosuppressive treatments.

Management of severe renal disease in anti-neutrophil-cytoplasmic-antibody-associated vasculitis: the place of rituximab and plasma exchange?

OBJECTIVE: The optimal induction therapy for severe glomerulonephritis of ANCA-associated vasculitis (AAV) is debated. We compared the efficacy of glucocorticoid and rituximab (RTX) or CYC induction therapy for severe AAV-related glomerulonephritis and evaluated the potential benefit of plasma exchange (PE) as adjunct therapy to CYC. METHODS: This retrospective, multicentre study included AAV patients with severe renal active disease (serum creatinine level ≥350 µmol/l and/or estimated glomerular filtration ratio ≤15 ml/min/1.73 m2). Propensity-score analysis was used to adjust for potential confounders. RESULTS: Between 2005 and 2017, 153 patients with AAV-related glomerulonephritis were studied (96 [60%] men; mean [s.d.] age 63 [13.1] years): 19 (12%) were treated with RTX and 134 (88%) with CYC. Remission rates did not differ between RTX- and CYC-treated groups. Although more patients with RTX than CYC were dialysis-free at month (M) 12 (79% vs 68%), the difference was not significant after adjustment. Among 134 patients with CYC-treated glomerulonephritis, 76 (57%) also had PE. M3 and M6 remission rates were comparable for weighted CYC groups with or without PE. For weighted groups, the dialysis-free survival rate with CYC was higher with than without PE at M6 (72% vs 64%; odds ratio 2.58) and M12 (74% vs 60%; odds ratio 2.78) reaching statistical significance at M12. CONCLUSION: We could not find any difference between RTX and CYC as induction therapy for patients with severe AAV-related glomerulonephritis. In patients receiving CYC induction regimen, the addition of PE conferred short-term benefits with higher dialysis-free rate at M12.

Immunoglobulin A nephropathy in association with inflammatory bowel diseases: results from a national study and systematic literature review.

BACKGROUND: Little is known about clinical characteristics and kidney outcomes in patients with biopsy-proven immunoglobulin A nephropathy (IgAN) in a context of inflammatory bowel disease (IBD). METHODS: We conducted a retrospective multicentre study with a centralized histological review to analyse the presentation, therapeutic management and outcome of 24 patients suffering from IBD-associated IgAN relative to a cohort of 134 patients with primary IgAN without IBD. RESULTS: Crohn's disease and ulcerative colitis accounted for 75 and 25% of IBD-associated IgAN cases, respectively. IBD was diagnosed before IgAN in 23 cases (a mean of 9 years previously) and was considered active at IgAN onset in 23.6% of patients. Hypertension was present in 41.7% of patients. The urinary protein:creatinine ratio exceeded 100 mg/mmol in 70.8% of patients (mean 254 mg/mmol). Estimated glomerular filtration rate (eGFR) was >60 mL/min/1.73 m2 in 13/24 patients and only 1 patient required dialysis. In the Oxford mesangial hypercellularity, endocapillary cellularity, segmental sclerosis and interstitial fibrosis/tubular atrophy with crescents classification of renal biopsies, 57% were M1, 48% E1, 76% S1, 57% T1-2 and 38% C1-2. Steroids were administered in 50% of cases. After a mean follow-up of 7.2 years, 4 patients (16.7%) had a poor kidney outcome: end-stage renal disease (n = 3) or a >50% decrease in eGFR from initial values (n = 1). A similar evolution was observed in patients with primitive IgAN. CONCLUSIONS: This first case series suggests that IBD-associated IgAN has frequent inflammatory lesions at onset and variable long-term outcomes.

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.

Impact of pre-eclampsia on renal outcome in sickle cell disease patients.

The long-term consequences of pre-eclampsia (PrE) for renal function have never been determined in patients with sickle cell disease (SCD). Between 2008 and 2015, we screened 306 pregnancies in women with SCD and identified 40 with PrE (13%). The control group consisted of 65 pregnant SCD patients without PrE. In multivariable analysis, PrE events were associated with an increase of 1 log of lactate dehydrogenase level (adjusted odds ratio, aOR = 3·83, P = 0·05), a decrease of 10 g/l of haemoglobin levels (aOR = 2·48, P = 0·006) and one or more vaso-occlusive crisis during pregnancy (aOR = 16·68, P = 0·002). Estimated glomerular filtration rate (eGFR) was similar in the two groups at steady state but was significantly lower in the PrE group after one year of follow-up and at last follow-up (130 vs 148 ml/min/1·73 m2 , P < 0·001 and 120 vs 130 ml/min/1·73 m2 , P < 0·001, respectively). In multivariable analysis, eGFR had returned to steady-state levels one year after pregnancy in patients without PrE but continued to decrease in patients with PrE (ß = -18·15 ml/min/1·73 m2 , P < 0·001). This decline was more marked at the end of follow-up (ß = -31·15 ml/min, P < 0·001). In conclusion, PrE episodes are associated with a significant risk of subsequent renal function decline in SCD patients.

Randall-type monoclonal immunoglobulin deposition disease: novel insights from a nationwide cohort study.

Monoclonal immunoglobulin deposition disease (MIDD) is a rare complication of B-cell clonal disorders, defined by Congo red negative-deposits of monoclonal light chain (LCDD), heavy chain (HCDD), or both (LHCDD). MIDD is a systemic disorder with prominent renal involvement, but little attention has been paid to the description of extrarenal manifestations. Moreover, mechanisms of pathogenic immunoglobulin deposition and factors associated with renal and patient survival are ill defined. We retrospectively studied a nationwide cohort of 255 patients, with biopsy-proven LCDD (n = 212) (including pure LCDD [n = 154], LCDD with cast nephropathy (CN) [n = 58]), HCDD (n = 23), or LHCDD (n = 20). Hematological diagnosis was monoclonal gammopathy of renal significance in 64% and symptomatic myeloma in 34%. Renal presentation was acute kidney injury in patients with LCCD and CN, and chronic glomerular disease in the other types, 35% of whom had symptomatic extrarenal (mostly hepatic and cardiac) involvement. Sequencing of 18 pathogenic LC showed high isoelectric point values of variable domain complementarity determining regions, possibly accounting for tissue deposition. Among 169 patients who received chemotherapy (bortezomib-based in 58%), 67% achieved serum free light chain (FLC) response, including very good partial response (VGPR) or above in 52%. Renal response occurred in 62 patients (36%), all of whom had achieved hematological response. FLC response ≥ VGPR and absence of severe interstitial fibrosis were independent predictors of renal response. This study highlights an unexpected frequency of extrarenal manifestations in MIDD. Rapid diagnosis and achievement of deep FLC response are key factors of prognosis.

Circulating plasmablasts and high level of BAFF are hallmarks of minimal change nephrotic syndrome in adults.

BACKGROUND: The recent success achieved with the use of B cell-depleting agents in some patients with minimal change nephrotic syndrome (MCNS) suggests an unexpected role for B lymphocytes in the pathogenesis of this immune-mediated glomerular disease. Nevertheless, no extensive B-cell phenotyping analysis has ever been performed in untreated adult patients soon after MCNS diagnosis. METHODS: We investigated the distribution of the different B-cell subpopulations in 22 untreated adult patients with biopsy-proven MCNS [MCNS relapse (MCNS-Rel)]. We compared these data with those for 24 healthy controls, 13 MCNS patients in remission (with no specific treatment) and 19 patients with idiopathic membranous nephropathy (IMN). RESULTS: Patients with MCNS-Rel or IMN had higher proteinuria and lower serum albumin and gammaglobulin levels (P < 0.0001 for all comparisons) than MCNS patients in remission. Plasmablasts were the only B-cell subsets present at significantly higher levels in MCNS-Rel patients than in the patients of the other three groups (P < 0.05 for all comparisons). The lower albumin levels and higher proteinuria levels were positively correlated with the percentage of circulating plasmablasts (Spearman test's ρ = -0.54, P = 0.01 and ρ = 0.65, P = 0.002, respectively). Similarly, the increase of immunoglobulin M (IgM) and the decrease of IgG levels were significantly associated with the percentage of plasmablasts in MCNS-Rel patients (Spearman's ρ = 0.36, P = 0.01 and Spearman's ρ = -0.60, P = 0.01, respectively). Increased production of interleukin (IL)-21, IL-6 and B-cell activating factor (BAFF) in the serum of MCNS-Rel patients was found significantly correlated with the percentage of plasmablasts (ρ = 0.72, P = 0.0002, ρ = 0.49, P = 0.04 and ρ = 0.62, P = 0.009, respectively). CONCLUSIONS: An increase in the proportion of circulating plasmablasts seems to be a hallmark of untreated MCNS in adult patients. Further studies are required to more precisely determine the phenotype and functions of these cells.

The spectrum of kidney biopsies in hospitalized patients with COVID-19, acute kidney injury, and/or proteinuria.

We report a multicentric retrospective case series of patients with COVID-19 who developed acute kidney injury and/or proteinuria and underwent a kidney biopsy in the Paris and its metropolitan area. Forty-seven patients (80.9% men) with COVID-19 who underwent a kidney biopsy between March 08 and May 19, 2020 were included. Median age was 63 years IQR [52-69]. Comorbidities included hypertension (66.0%), diabetes mellitus (27.7%), obesity (27.7%), history of chronic kidney (25.5%), cardiac (38.6%) and respiratory (27.3%) diseases. Initial symptoms were fever (85.1%), cough (63.8%), shortness of breath (55.3%), and diarrhea (23.4%). Almost all patients developed acute kidney injury (97.9%) and 63.8% required renal replacement therapy. Kidney biopsy showed two main histopathological patterns, including acute tubular injury in 20 (42.6%) patients, and glomerular injury consisting of collapsing glomerulopathy and focal segmental glomerulosclerosis in 17 (36.2%) patients. Two (4.3%) patients had acute vascular nephropathy, while eight (17%) had alternative diagnosis most likely unrelated to COVID-19. Acute tubular injury occurred almost invariably in the setting of severe forms of COVID-19, whereas patients with glomerular injury had various profiles of COVID-19 severity and collapsing glomerulopathy was only observed in patients harboring a combination of APOL1 risk variants. At last follow-up, 16 of the 30 patients who initially required dialysis were still on dialysis, and 9 died. The present study describes the spectrum of kidney lesions in patients with COVID-19. While acute tubular injury is correlated with COVID-19 severity, the pattern of glomerular injury is intimately associated with the expression of APOL1 risk variants.