Anti-LDL Receptor-Related Protein 2 Nephropathy with Synchronous Primary Kidney Extranodal Marginal Zone Lymphoma.

Introduction: Anti-LDL receptor-related protein 2 (anti-LRP2) nephropathy is a rare but progressive form of autoimmune-mediated tubulointerstitial nephritis and glomerular disease, characterized by a classic pattern of immune complex deposition in the kidney. A theoretic link between autoimmune disease and lymphoproliferative diseases exists, and therefore, in some cases autoimmune-mediated inflammation and lymphoproliferative neoplasm can co-exist in the same site. Case Presentation: An elderly man presented with 6 months of weight loss and fatigue. Subsequent workup showed an elevated serum creatinine and subnephrotic range proteinuria. Kidney biopsy was performed which revealed anti-LRP2 nephropathy with concurrent primary kidney extranodal marginal zone lymphoma. He was subsequently treated with rituximab but remains dialysis-dependent (12 months after his initial diagnosis, at time of publication of this report). Conclusion: We discuss the bidirectional relationship between autoimmune disease and lymphoma in the kidney, along with a brief review of the literature pertaining to these rare lesions. Our case report highlights the diagnostic difficulties faced by pathologists when encountering this entity. We also attempt to spread awareness about the co-existence of tubulointerstitial inflammation and lymphoproliferative disorder, which may be under-recognized.

Complete remission of nephrotic syndrome in a young woman with anti-LRP2 nephropathy after immunosuppressive therapy.

BACKGROUND: Anti-low density lipoprotein receptor-related protein 2 (LRP2) nephropathy/anti-brush border antibody (ABBA) disease is a disorder characterized by acute tubulointerstitial injury associated with circulating antibodies to kidney proximal tubular brush border protein LRP2/megalin. Patients are typically elderly and present with acute kidney injury and subnephrotic proteinuria. They progress to end-stage renal disease with poor response to immunosuppressive therapies. CASE PRESENTATION: We report a case of a 29-year-old Chinese woman, who presented with nephrotic syndrome with normal kidney function. Kidney biopsy showed no obvious tubular injury or interstitial inflammation. Positive immunoglobulin G (IgG) staining was revealed along the brush border of proximal tubular cells. Anti-LRP2 antibody was identified in serum, consistent with a diagnosis of anti-LRP2 nephropathy. The patient achieved complete remission after receiving prednisone and cyclophosphamide. CONCLUSIONS: Anti-LRP2 nephropathy can also present as nephrotic syndrome in young patients and complete remission from nephrotic syndrome may be achieved after immunosuppressive therapy.

Anti-LRP2 nephropathy with concurrent kidney infiltration by lymphoma.

Anti-low-density lipoprotein receptor-related lipoprotein 2 (LRP2) nephropathy/anti-brush border antibody disease is rare and characterized by tubular basement membrane, Bowman's capsule and glomerular subepithelial immune deposits on kidney biopsy. No reported cases have occurred in patients with lymphoproliferative disorders or monoclonal gammopathies. We present two cases of anti-LRP2 nephropathy that occurred in patients with progressive low-grade B-cell lymphoma and had concurrent kidney infiltration by lymphoma on biopsy. We speculate that underlying immune dysregulation related to lymphoma may contribute to the development of this rare autoimmune kidney disease in some patients.

Anti-LRP2 Nephropathy With Abundant IgG4-Positive Plasma Cells: A Case Report.

In older adults, the most common kidney biopsy diagnoses include pauci-immune crescentic glomerulonephritis, membranous nephropathy, and focal segmental glomerulosclerosis. Recently, investigators described a small series of older patients (aged 66-80 years) with acute kidney injury and a kidney biopsy demonstrating tubular basement membrane (TBM) immune deposits of polytypic immunoglobulin G (IgG) and C3, acute tubular injury, and tubulointerstitial inflammation. They identified a circulating antibody against kidney tubular low-density lipoprotein (LDL) receptor-related protein 2 (LRP2; also known as megalin) in patients' sera and colocalization of LRP2 with IgG in TBM deposits. We present a rare case of anti-LRP2 nephropathy/anti-brush border antibody disease and describe the novel feature of abundant IgG4-positive interstitial plasma cells. Along with the combination of TBM deposits, tubulointerstitial nephritis (TIN), and segmental glomerular subepithelial immune deposits seen in both entities, this newly described feature adds to the morphologic overlap with IgG4-related TIN. Identification of large TBM deposits using light microscopy and IgG staining of apical aspects of proximal tubules using immunofluorescence microscopy can point to the correct diagnosis of anti-LRP2 nephropathy and prompt confirmatory studies. Particularly in older patients with immune complex-mediated TIN who lack clinical, laboratory, radiographic, and/or characteristic histologic features of IgG4-TIN or other autoimmune, infectious, or drug-related injury, a diagnosis of anti-LRP2 nephropathy should be considered.

Single-Cell Transcriptomics Characterizes Cell Types in the Subventricular Zone and Uncovers Molecular Defects Impairing Adult Neurogenesis.

Neural stem cells (NSCs) contribute to plasticity and repair of the adult brain. Niches harboring NSCs regulate stem cell self-renewal and differentiation. We used comprehensive and untargeted single-cell RNA profiling to generate a molecular cell atlas of the largest germinal region of the adult mouse brain, the subventricular zone (SVZ). We characterized >20 neural and non-neural cell types and gained insights into the dynamics of neurogenesis by predicting future cell states based on computational analysis of RNA kinetics. Furthermore, we applied our single-cell approach to document decreased numbers of NSCs, reduced proliferation activity of progenitors, and perturbations in Wnt and BMP signaling pathways in mice lacking LRP2, an endocytic receptor required for SVZ maintenance. Our data provide a valuable resource to study adult neurogenesis and a proof of principle for the power of single-cell RNA sequencing to elucidate neural cell-type-specific alterations in loss-of-function models.

Adonesine A1 receptor and megalin defect in diabetic mice with early kidney disease / 中华肾脏病杂志

Objective To observe the effect of adenosine A1 receptor (A1AR) on the megalin defect in type 1 diabetic mice with early kidney disease.Methods 7-8 week-old,baseline body weight and fasting blood glucose matched wild type (WT) C57BL/6J mice were selected,and randomly divided into two groups:control group (n=6) and WT DM group (n=6).In the same way,male A1AR knock-out C57BL/6J mice were selected as A1AR-/-DM group (n=6).DM model was established by intraperitoneal injection of streptozocin.The blood glucose (BG),body weight (BW),kidney weight (KW),24 h proteinuria (24hUP) and albumin creatine ratio (ACR) were measured at 4 weeks.The renal pathological lesion was observed and the expression of megalin in proximal tubules was examined by immunohistochemistry.The expression of caspase-1,IL-18 and A1AR were detected by Western blotting.Results At 4th week,compared with WT control mice,the BG,BW,KW and 24hUP of WT DM mice were increased significantly (n=6,P ＜ 0.01),with the pathological glomerular enlargement,mesangial cell proliferation,extracellular matrix accumulation and renal tubule hypertrophy being observed.Immunohistochemistry revealed decreased expression of megalin,an important multiligand protein receptor on the brush border of proximal tubular epithelial cells in WT DM mice,which was correlated with 24hUP (r=-0.645,P ＜ 0.01).Compared with the control mice,the expressions of caspase-1,IL-18 and A1AR were significantly increased in WT DM mice (P ＜ 0.05).For A1AR-/-DM mice,more serious pathological lesion and megalin defect,together with increasing of casapase-1 and heavier proteinuria were observed than those in WT DM mice.Conclusion A1AR may play a protective role in megalin expression of diabetic mice with early kidney disease,in which the mechanism may be associated with caspase-1 related pyroptosis pathway.The details need further exploration.