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.

AA amyloidosis complicating monoclonal gammopathies, an unusual feature validating the concept of "monoclonal gammopathy of inflammatory significance"?

INTRODUCTION: AL amyloidosis is caused by the proliferation of an immunoglobulin-secreting B cell clone. AA amyloidosis is a rare complication of chronic inflammation. However, some patients present with diseases combining monoclonal immunoglobulin production and chronic inflammation. The aim of this work was to describe cases of AA amyloidosis associated with monoclonal gammopathies. PATIENTS AND METHODS: We reviewed all patients reported in French national amyloid centres presenting with AA amyloidosis and monoclonal gammopathy and performed a literature review. The quality of AA amyloidosis diagnosis and the causal relationship with monoclonal gammopathy were assessed. RESULTS: In total, four patients from our centres and eight from the literature fulfilled the inclusion criteria. The haematological disorders presenting with monoclonal gammopathy were as follows: Waldenström macroglobulinaemia (n = 8), Schnitzler syndrome (n = 2), multiple myeloma (n = 1) and monoclonal gammopathy of undetermined significance (n = 1). Treatment strategies varied among the cases, with the treatment of the haematological disorder in 4 and anti-inflammatory treatment in 2. CONCLUSION: Monoclonal gammopathies might be a rare and poorly known cause of AA amyloidosis. Such monoclonal gammopathies could be named "monoclonal gammopathies of inflammatory significance."

Apheresis in Adult With Refractory Idiopathic Nephrotic Syndrome on Native Kidneys.

BACKGROUND: Apheresis is the gold standard for idiopathic nephrotic syndrome (INS) relapse after transplantation, but it remains unknown whether such treatment is useful for adults with refractory INS on native kidneys. METHODS: This retrospective study included patients older than 16 years with biopsy-proven refractory (persistent nephrotic syndrome on corticosteroids plus at least 1 immunosuppressive drug) INS treated by apheresis and followed for at least 3 months. RESULTS: Between September 1997 and January 2020, 21 patients (focal segmental glomerulosclerosis: 12, minimal change nephrotic syndrome: 9, men: 67%, median age: 34 years) were identified. At last follow-up (12 months), 7 of 21 patients were in complete or partial remission. Remission was associated with older age (51 vs. 30 years, P = 0.05), lower proteinuria (3.9 vs. 7.3 g/d, P = 0.03), and lower estimated glomerular filtration rate (eGFR) (28.0 vs. 48.5 ml/min per 1.73 m2, P = 0.05) at apheresis. The need for dialysis before apheresis (odds ratio [OR] 22.0 [1.00-524], P = 0.026), age ≥50 years (OR: 22.6 [1.00-524], P = 0.006), a marked (>4.5 g/d) decrease in proteinuria (OR: 9.17 [1.15-73.2], P = 0.041), and a short (<12 months) time between diagnosis and apheresis (OR: 10.8 [1-117], P = 0.043) were significantly associated with remission. Three of 7 patients in remission who were initially on dialysis became dialysis-free; by contrast, none of the 14 patients without remission was initially on dialysis, but 5 of 14 had become dialysis-dependent (P = 0.01). CONCLUSION: Apheresis may result in remission in adult patients with refractory INS, particularly in those at risk of renal failure, with limited sensitivity to medical treatments, if apheresis is initiated within a year of diagnosis.

AA Amyloidosis in the Course of HIV Infection: A Report of 19 Cases Including 4 New French Cases and a Comprehensive Review of Literature.

INTRODUCTION: HIV infection has been recently retained as an unclear cause of AA amyloidosis. Our aim was to investigate cases of AA amyloidosis associated with HIV infection to understand if it could be considered as a cause of AA amyloidosis. METHODS: A comprehensive literature review was conducted as well as retrospective study from French cases collected from our national reference center for AA amyloidosis. RESULTS: Altogether, 19 patients with AA amyloidosis and HIV infection were found with 68% of men and median age at amyloidosis diagnosis of 38 years (range 28-75 years). Clinical presentation was nephrotic syndrome in 94% (n = 17/18). Among patients with renal involvement and assessable outcome (n = 17), 11 (64.7%) progressed to chronic kidney disease, with 6 (35%) end-stage renal disease. Seventy-five percent of patients had uncontrolled HIV infection and 71.4% CD4 counts <400/mm3 at amyloidosis diagnosis. Repeated or chronic bacterial or fungal infection was found in 47% of cases and a history of parenteral drug use in 55% of patients. Three patients had no classical or at least no suspected AA amyloidosis cause found or reported. CONCLUSIONS: AA Amyloidosis is a rare condition in HIV patients with common renal involvement and significant risk of progression to chronic renal insufficiency. Because of the frequency related to other inflammatory conditions in this population, HIV is probably not an independent risk factor for AA amyloidosis.

Epidemiology of Castleman disease associated with AA amyloidosis: description of 2 new cases and literature review.

Introduction: HHV8-negative Castleman disease (CD) is classified as hyaline vascular (HV) type, or mixed or plasma cell (PC) types. It may present as multicentric CD (MCD) or unicentric CD (UCD). CD is a rare cause of AA amyloidosis (AAA). We aimed to report the main features of CD with secondary AAA through a description of new cases and a systematic literature review. Patients and methods: New cases were identified from the French National Reference Center for AAA. A systematic literature review was performed to identify HHV8-negative CD cases associated with AAA. Results: Thirty-seven patients were analysed, consisting of two new cases and 35 from literature. Twenty-three had UCD and 14 had MCD. PC was the main histologic subtype (n = 25; 68%) in both UCD and MCD patients. Surgical excision of UCD was performed in 21 patients (91%) with a favourable outcome, except for four patients (19%). Clinical and biologic remission was achieved in six patients with MCD (43%), all of whom were treated with anti-interleukin-6 (IL-6) therapy. Conclusions: AAA is a rare complication of CD, namely idiopathic MCD and UCD presenting with the PC histologic subtype. Surgical excision of UCD should be the first-line treatment whenever possible, while anti-IL-6 therapies seem effective for MCD.

Decreased expression of megalin and cubilin and altered mitochondrial activity in tenofovir nephrotoxicity.

Tenofovir disoproxil fumarate (TDF) is a commonly used antiretroviral drug for HIV, rarely causing Fanconi syndrome and acute kidney injury. We retrospectively analyzed the clinico pathological presentation of 20 cases of tenofovir-induced tubulopathy, and investigated the renal expression of the megalin and cubilin proteins, as well as the mitochondrial respiratory chain activity. Estimated glomerular filtration rate (eGFR) before TDF exposure was 92 ml/min/1.73m2, decreasing to 27.5 ml/min/1.73m2 at the time of biopsy, with 30% of patients requiring renal replacement therapy. Proximal tubular expression of megalin and cubilin was altered in 19 and 18 cases, respectively, whereas it was preserved in patients exposed to TDF without proximal tubular dysfunction and in HIV-negative patients with acute tubular necrosis. Loss of megalin/cubilin was correlated with low eGFR and high urine retinol binding protein at the time of biopsy, low eGFR at last follow-up, and was more severe in patients with multifactorial toxicity. Patients with additional nephrotoxic conditions promoting tenofovir accumulation showed a lower eGFR at presentation and at last follow-up, and more severe lesions of acute tubular necrosis, than those with isolated tenofovir toxicity. Altered mitochondrial COX activity in proximal tubules was observed and may be an early cellular alteration in tenofovir nephrotoxicity. In conclusion, altered megalin/cubilin expression represents a distinctive feature in tenofovir-induced tubulopathy, and its severity is correlated with urine retinol binding protein loss and is associated with a poor renal prognosis. Concomitant exposure to other nephrotoxic conditions severely impacts the renal presentation and outcome.

Multiplex and accurate quantification of acute kidney injury biomarker candidates in urine using Protein Standard Absolute Quantification (PSAQ) and targeted proteomics.

There is a need for multiplex, specific and quantitative methods to speed-up the development of acute kidney injury biomarkers and allow a more specific diagnosis. Targeted proteomic analysis combined with stable isotope dilution has recently emerged as a powerful option for the parallelized evaluation of candidate biomarkers. This article presents the development of a targeted proteomic assay to quantify 4 acute kidney injury biomarker candidates in urine samples. The proteins included in the assessed panel consisted of myo-inositol oxygenase (MIOX), phosphoenolpyruvate carboxykinase 1 (PCK1), neutrophil gelatinase-associated lipocalin (NGAL) and liver fatty acid-binding protein (L-FABP). The proteomic assay combined an antibody-free sample preparation and a liquid chromatography-selected reaction monitoring (LC-SRM) analysis pipeline. For accurate quantification of the selected candidates, we used PSAQ (Protein Standard Absolute Quantification) standards which are isotopically labeled versions of the target proteins. When added directly to the biological samples, these standards improve detection specificity and quantification accuracy. The multiplexed assay developed for the 4 biomarker candidates showed excellent analytical performance, in line with the recommendations of health authorities. Tests on urine from two small patient cohorts and a group of healthy donors confirmed the relevance of NGAL and L-FABP as biomarkers for AKI diagnosis. The assay is readily adaptable to other biomarker candidates and should be very useful for the simultaneous and accurate quantification of multiple biomarkers.