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.

Ifosfamide nephrotoxicity in adult patients.

BACKGROUND: Ifosfamide, a widely prescribed antineoplasic agent, is frequently associated with kidney dysfunction. Its nephrotoxicity is well documented in children, but data are lacking in adult patients. METHODS: The aim of this retrospective study was to describe the clinical, biological and histological characteristics of ifosfamide nephrotoxicity. RESULTS: We report 34 patients (median age: 41 years) admitted in six French nephrology departments for kidney failure and/or tubular dysfunction. Fifteen patients (44.1%) received cisplatin as part of their chemotherapy. In 6 patients (17.7%), ifosfamide nephrotoxicity was revealed by a proximal tubular dysfunction (PTD), in 5 patients (14.4%) by an acute kidney injury (AKI), in 6 patients (17.7%) by a chronic kidney disease (CKD) and in 17 patients (49.7%) by an association of PTD and AKI. Fourteen renal biopsies (41.2%) were performed and revealed acute tubular necrosis (85.7%), vacuolation (78.6%) and nuclear atypias (71.4%) of renal epithelial cells, interstitial inflammation (71.4%) and fibrosis (57.1%). Electron microscopy showed mitochondrial enlargement and dysmorphic changes suggestive of mitochondrial toxicity. Ten patients (29.4%) progressed to Stage 5 CKD, six (17.6%) required haemodialysis and six patients died during a median follow-up period of 31 months. Risk factors for Stage 5 CKD were age and cisplatin co-administration.

[Pediatric nephrology: What should an adult nephrologist know about these diseases?] / Néphrologie pédiatrique : que doit savoir un néphrologue d'adulte sur ces pathologies ?

In nephrology, some diseases begin specifically during childhood; however, they must be known by adult nephrologists so that to ensure continuity and homogeneity for their management. The aim of this review is therefore to propose a brief overview of the main pediatric diseases, for which a specific knowledge is warranted, and notably pediatric idiopathic nephrotic syndrome, cystinosis, primary hyperoxaluria and hereditaries tubulopathies.

Midterm Outcomes of 12 Renal Transplant Recipients Treated With Eculizumab to Prevent Atypical Hemolytic Syndrome Recurrence.

BACKGROUND: Atypical hemolytic uremic syndrome (aHUS) is an orphan disease with a high rate of recurrence after kidney transplantation. However, reports of successful prevention of posttransplant aHUS recurrence with eculizumab emerged a few years ago. To further delineate its optimal use, we describe the largest series of kidney transplant recipients treated with prophylactic eculizumab. METHODS: Twelve renal transplant recipients with aHUS-related end-stage renal disease received eculizumab: 10 from day 0 and 2 at the time of recurrence (days 6 and 25). Clinical and histological features, complement assessment, and free eculizumab measurements were analyzed. The median follow-up was 24.6 months. RESULTS: Five patients had failed at least 1 previous renal transplant from aHUS. A genetic mutation was identified in 9 patients, anti-H antibodies were found in 2. No patient demonstrated biological recurrence of thrombotic microangiopathy under treatment. Three antibody-mediated rejections (AMRs) occurred without detectable C5 residual activity. AMR was associated with subclinical thrombotic microangiopathy in 2 patients. One patient lost his graft after several complications, including AMR. One patient experienced posttransplant C3 glomerulonephritis. The last median serum creatinine was 128.2 ± 40.8 µmol/L. CONCLUSIONS: These data confirm that eculizumab is highly effective in preventing posttransplantation aHUS recurrence, yet may not fully block AMR pathogenesis.

Urinary retinol binding protein is a marker of the extent of interstitial kidney fibrosis.

Currently, a non-invasive method to estimate the degree of interstitial fibrosis (IF) in chronic kidney disease is not available in routine. The aim of our study was to evaluate the diagnostic performance of the measurement of urinary low molecular weight (LMW) protein concentrations as a method to determine the extent of IF. The urines specimen from 162 consecutive patients who underwent renal biopsy were used in the analysis. Numerical quantification software based on the colorimetric analysis of fibrous areas was used to assess the percentage IF. Total proteinuria, albuminuria, and the urinary levels of retinol binding protein (RBP), alpha1-microglobulin (α1MG), beta 2-microglobulin (ß2MG), transferrin, and IgG immunoglobulins were measured. There was a significant correlation between the degree of IF and the RBP/creatinine (creat) ratio (R2: 0.11, p<0.0001). IF was associated to a lesser extent with urinary ß2MG and α1MG; however, there was no association with total proteinuria or high molecular weight (HMW) proteinuria. The correlation between IF and RBP/creat remained significant after adjustment to the estimated glomerular filtration rate, age, body mass index, α1MG, and ß2MG. The specificity of the test for diagnosing a fibrosis score of >25% of the parenchyma was 95% when using a threshold of 20 mg/g creat. In conclusion, RBP appears to be a quantitative and non-invasive marker for the independent prediction of the extent of kidney IF. Because methods for the measurement of urinary RBP are available in most clinical chemistry departments, RBP measurement is appealing for implementation in the routine care of patients with chronic kidney disease.

[Granulomatosis with polyangiitis (Wegener's granulomatosis)]. / Granulomatose avec polyangéite (maladie de Wegener).

Granulomatosis with polyangiitis (GPA), is the recently proposed, new alternative name for Wegener's granulomatosis. It defines a systemic small-vessels vasculitis, characterized by frequent involvement of upper and lower respiratory tract. The presence of cytoplasmic-type ANCA with anti-proteinase 3 specificity is observed in more than 90% of patients with GPA but is not mandatory for the definition of the disease, which is based on clinical criteria and presence of granulomas on the tissue biopsy. Necrotizing glomerulonephritis is observed in more than 50% of patients, and has important prognostic value, requiring urgent therapeutic intervention. Classical immunosuppressive schemes used in GPA combine high-dose corticosteroids and cyclophosphamide, but recent trials have shown that rituximab offers a similar efficacy with probably less cytotoxic side-effects. The best maintenance treatment is not yet defined, but the prevention of relapses remains the main therapeutic challenge in this vasculitis.

Calpastatin controls polymicrobial sepsis by limiting procoagulant microparticle release.

RATIONALE: Sepsis, a leading cause of death worldwide, involves widespread activation of inflammation, massive activation of coagulation, and lymphocyte apoptosis. Calpains, calcium-activated cysteine proteases, have been shown to increase inflammatory reactions and lymphocyte apoptosis. Moreover, calpain plays an essential role in microparticle release. OBJECTIVES: We investigated the contribution of calpain in eliciting tissue damage during sepsis. METHODS: To test our hypothesis, we induced polymicrobial sepsis by cecal ligation and puncture in wild-type (WT) mice and transgenic mice expressing high levels of calpastatin, a calpain-specific inhibitor. MEASUREMENTS AND MAIN RESULTS: In WT mice, calpain activity increased transiently peaking at 6 hours after cecal ligation and puncture surgery. Calpastatin overexpression improved survival, organ dysfunction (including lung, kidney, and liver damage), and lymphocyte apoptosis. It decreased the sepsis-induced systemic proinflammatory response and disseminated intravascular coagulation, by reducing the number of procoagulant circulating microparticles and therefore delaying thrombin generation. The deleterious effect of microparticles in this model was confirmed by transferring microparticles from septic WT to septic transgenic mice, worsening their survival and coagulopathy. CONCLUSIONS: These results demonstrate an important role of the calpain/calpastatin system in coagulation/inflammation pathways during sepsis, because calpain inhibition is associated with less severe disseminated intravascular coagulation and better overall outcomes in sepsis.