[Membranous nephropathy]. / Glomérulonéphrite extramembraneuse.

"Membranous nephropathy Membranous nephropathy is the leading cause of nephrotic syndrome in adults, and results from immune complex deposition on the subepithelial surface of the glomerular basement membrane. Its outcome is unpredictable, and membranous nephropathy is associated with significant rates of kidney failure. The auto-immune nature of the disease was confirmed in the last decade with the discovery of a growing list of podocyte antigens targeted by autoantibodies, e.g. phospholipase A2 receptor (PLA2R). In the meantime, the management of patients with membranous nephropathy has changed dramatically through the evaluation of new therapeutic molecules, such as anti-B cell monoclonal antibodies, in clinical trials."

"Glomérulonéphrite extramembraneuse La glomérulonéphrite extramembraneuse est la principale cause de syndrome néphrotique chez l'adulte et est causée par le dépôt de complexes immuns sur le versant sous-épithélial de la membrane basale glomérulaire. Son évolution, difficilement prédictible, est associée à un risque d'insuffisance rénale terminale. La nature auto-immune de la maladie a été confirmée au cours de la précédente décennie, grâce à la découverte d'une liste croissante d'antigènes glomérulaires podocytaires cibles d'auto-anticorps, notamment le récepteur de la phospholipase A2 (PLA2R). Parallèlement, des essais thérapeutiques ont permis d'évaluer la place de nouvelles molécules thérapeutiques, comme les anticorps monoclonaux antilymphocyte B, modifiant radicalement la prise en charge des patients atteints de glomérulonéphrite extramembraneuse."

Infliximab for relapsing neurosarcoidosis recurring after kidney transplantation: a case report.

Neurological involvement of sarcoidosis is a rare condition, and its occurrence in the context of transplantation is exceptional. Moreover, treatment can be challenging. We report the unusual case of a patient transplanted with a kidney for end-stage renal disease secondary to sarcoidosis who experienced a neurological recurrence of the disease under immunosuppressive treatment, translating in behavioural aggressiveness, social withdrawal and weight loss. He relapsed thrice under corticosteroids but responded finally to infliximab. This case highlights the potential of sarcoidosis to recur neurologically after kidney transplantation despite immunosuppressive treatment. Also, treatment of relapsing neurosarcoidosis can be challenging and may benefit from TNF-α blockers.

Podocyte Antigen Staining to Identify Distinct Phenotypes and Outcomes in Membranous Nephropathy: A Retrospective Multicenter Cohort Study.

RATIONALE & OBJECTIVE: Membranous nephropathy (MN) is characterized by the deposition of immune complexes along glomerular basement membranes. M-Type phospholipase A2 receptor (PLA2R), thrombospondin type 1 domain-containing 7A (THSD7A), exostosin 1 and 2 (EXT1/2), and neural epidermal growth factor-like 1 protein (NELL-1) have been identified as established or potential podocyte antigens in MN. We investigated the association of podocyte antigen staining with MN clinical phenotype and outcomes. STUDY DESIGN: Multicenter retrospective cohort study. SETTING & PARTICIPANTS: 177 consecutive patients with MN unrelated to lupus erythematosus, identified after screening of 3,875 native kidney biopsies performed in the Belgian UCLouvain Kidney Disease Network from 2000 through 2018. PREDICTOR: Positive immunostaining for podocyte antigens on archived kidney biopsy samples. OUTCOMES: Association with different phenotypes (baseline characteristics of patients and pathologic findings on kidney biopsy), time to cancer and to kidney failure. ANALYTICAL APPROACH: Kaplan-Meier estimates and Cox regression analyses to assess time to cancer and kidney failure. RESULTS: 177 patients were followed up for a median of 4.0 (IQR, 1.3-8.0) years. Diagnosis of PLA2R-positive (PLA2R+), THSD7A+, and double-negative (PLA2R-/THSD7A-) MN was made in 117 (66.1%), 6 (3.4%), and 54 (30.5%) patients, respectively. Progression to kidney failure was similar in all groups. Although the number of patients with THSD7A+MN was small, they showed a higher incidence (50%) and increased risk for developing cancer during follow-up (adjusted HR, 5.0 [95% CI, 1.4-17.9]; P=0.01). 8% and 5% of patients with double-negative MN stained positively for EXT1/2 and NELL-1, respectively. Most patients with EXT1/2+MN were women, had features of systemic autoimmunity, and showed glomerular C1q deposits. LIMITATIONS: Retrospective design; small number of patients in the THSD7A group; lack of evaluation of immunoglobulin G subclasses deposition. CONCLUSIONS: Our real-world data describe the relative prevalence of subgroups of MN and support the hypothesis that a novel classification of MN based on podocyte antigen staining may be clinically relevant.

Rituximab in Patients With Phospholipase A2 Receptor-Associated Membranous Nephropathy and Severe CKD.

INTRODUCTION: Patients with phospholipase A2 receptor (PLA2R)-associated membranous nephropathy and stage 4 or 5 chronic kidney disease are at high risk of end-stage kidney disease. In recent years, rituximab (RTX) emerged as a safe and efficient treatment for patients with PLA2R-associated membranous nephropathy. Whether its use is also appropriate in patients with an estimated glomerular filtration rate <30 ml/min per 1.73 m2 has not been investigated. METHODS: We retrospectively reviewed characteristics and outcome of 13 patients with PLA2R-associated membranous nephropathy and stage 4 or 5 chronic kidney disease who received a total of 14 consecutive RTX treatments from January 2012 to March 2018. The treatment regimen consisted of either 2 weekly infusions of 375 mg/m2 or 2 RTX infusions of 1 g/d two weeks apart. When needed, the regimen was repeated to achieve immunological remission. RESULTS: The mean estimated glomerular filtration rate, serum albumin level, and urinary protein level at the first RTX infusion were 18 ± 7 ml/min per 1.73 m2, 25.2 ± 5.4 g/l, and 13.2 ± 7.5 g/d, respectively, with all patients being tested positive for serum PLA2R antibodies. Ten treatment courses led to an increase in estimated glomerular filtration rate and remission of nephrotic syndrome after a median follow-up of 40.8 months (interquartile range, 14.8-46.8). Conversely, 4 RTX treatments were unsuccessful, with patients requiring chronic hemodialysis within 1 year. The urinary albumin-to-protein ratio before treatment was predictive of renal response. Immunological remission occurred after 11 treatment courses and was associated with clinical response in 10 of 11 patients. Three patients experienced severe adverse events. CONCLUSION: RTX seems effective and reasonably safe in PLA2R-associated membranous nephropathy with stage 4 or 5 chronic kidney disease. Immunological remission is associated with a good clinical outcome.

Influence of hemodialysis on pramipexole pharmacokinetics: Lessons from two cases and literature review.

BACKGROUND: Restless legs syndrome (RLS) is not a rare condition in patients on long-term dialysis. Pramipexole is a small molecule used in the treatment of idiopathic and uremic RLS. Although some information concerning the efficacy and safety of pramipexole in uremic patients is available, data concerning the pharmacokinetics of pramipexole in hemodialysis (HD) are lacking. Following the occurrence of accidental pramipexole intoxication in a chronic HD patient, we were concerned about the efficacy of HD in removing pramipexole. Our aim was thus to assess plasma pramipexole concentrations and pramipexole clearance in a stable chronic HD patient without any residual kidney function. MATERIALS AND METHODS: Our patient was a 63-year-old man on chronic HD for 5 years who had been treated uneventfully with oral pramipexole for uremic RLS since then. During a routine 4-hour high-flux HD session, blood, ultrafiltrate, and dialysate samples were collected every hour to determine pramipexole concentrations over time. RESULTS: Pramipexole blood concentrations ranged from 12.1 to 23.9 µg/L. Pramipexole reduction ratio was 32.5%. Mean dialytic clearance of pramipexole was 76.8 mL/min. Postdialysis rebound was 5.6%. CONCLUSION: In the absence of any side effect, pramipexole blood concentrations at steady state were 2- to 4-fold higher than those observed in subjects with normal kidney function. Like other drugs with a high volume of distribution, pramipexole was poorly removed by HD. Therefore, HD is not recommended as a treatment option for pramipexole intoxication in patients with a glomerular filtration rate superior to 30 mL/min/1.73m².