Abstract: TH-PO537
PLA2R-AB Positive Malignancy-Associated Membranous Nephropathy: A Case Report
Session Information
- Trainee Case Reports - I
October 25, 2018 | Location: Exhibit Hall, San Diego Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Reports
- 1202 Glomerular Diseases: Immunology and Inflammation
Authors
- Habbach, Amr, Johns Hopkins Hospital, Baltimore, Maryland, United States
- Rosenberg, Avi Z., Johns Hopkins University, Baltimore, Maryland, United States
- Delsante, Marco, Universita'' degli Studi di Parma, Baltimore, Maryland, United States
- McMahon, Blaithin A., Johns Hopkins Hospital, Baltimore, Maryland, United States
Introduction
Membranous nephropathy (MN) is the most common cause of nephrotic syndrome in adults and the most frequent paraneoplastic glomerular disease associated with solid tumors. MN is either idiopathic (iMN) or secondary to malignancy (M-MN), infections, autoimmune diseases or drugs. Features such as the presence of the M-type Phospholipase A2 Receptor (PLA2R) antibodies and IgG subclass have been suggested to help distinguish idiopathic from secondary MN. However, 15-17% of cases of M-MN are anti PLA2R antibody positive, raising question about the specificity of these antibodies for the diagnosis of iMN. This is of importance as the treatment of this disease centers upon whether the disease is determined to be primary or secondary.
Case Description
We present here a case of a 78-year-old African female with pancreatic adenocarcinoma who was referred for lower extremity swelling and evaluation for proteinuria. A 24hr urine collection demonstrated 8.3 g of proteinuria and serum albumin of 1.3 g/dl. Her glomerular filtration rate was estimated to be 96 ml/min per 1.73/m2. Monoclonal gammopathy was not detected. Serum anti-PLA2R Antibodies were severely elevated, greater than 1500 RU/ml. A kidney biopsy revealed a prominent glomerular basement membrane and subepithelial deposits on electron microscopy. Anti-PLA2R AB was strongly positive on immunofluorescence. Features of paraneoplastic glomerulopathy were also present (near full-house pattern on IF, Kappa chain co-dominance, equivalent IgG4, IgG1 and IgG3 isotypes). The patient was empirically started on high dose corticosteroids given the preliminary result of proliferative glomerular disease and a near full-house pattern. She received capecitabine and radiotherapy with significant reduction in tumor size. Repeat Anti-PLA2R AB titers was 4 RU/ml
Discussion
This case highlights the complexity in trying to identify iMN from M-MN and the challenges facing the nephrologist in the treatment of this disease. The normalization of Anti-PLA2R AB in the setting of treating her malignancy suggests direct involvement of Anti-PLA2R AB in the mechanism of M-MN. Future studies are needed to evaluate the importance of anti PLA2R Antibodies in M-MN