Abstract: FR-PO666
IgG4 Related Membranous Nephropathy Treated With Anti-CD 20 Therapy
Session Information
- Glomerular Diseases: Clinical, Outcomes, Trials - II
November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1303 Glomerular Diseases: Clinical‚ Outcomes‚ and Trials
Authors
- Kalaria, Arjun Lalit, UPMC, Pittsburgh, Pennsylvania, United States
- Chen, Bo, UPMC, Pittsburgh, Pennsylvania, United States
- Ahmad, Syeda B., UPMC, Pittsburgh, Pennsylvania, United States
Introduction
Primary Membranous nephropathy (MN) is associated with autoantibodies against phospholipase A2 receptor (PLA2R) in the majority of cases. MN is associated with up to 10-15% of Immunoglobulin G4 (IgG4)-related kidney diseases. IgG4-related disease is an immune-mediated condition that can involve multiple organs and appear with lymphoplasmacytic infiltrations of IgG4+ plasma cells, storiform fibrosis, obliterative phlebitis, mild to moderate eosinophilia, and remarkably high serum IgG and IgG4. We report a rare case of IgG4-related MN treated with Rituximab.
Case Description
Our patient is a 66-year-old woman with hypertension, allergic rhinitis, and osteopenia who was referred to nephrology for new-onset edema. She denied NSAID use and had been up to date on her cancer screening. A 24hr urine protein was noted to have nephrotic range proteinuria of 5518 mg/24h. Labs showed a creatinine 0.8 mg/dL, BUN 12 mg/dL, serum albumin 2.3 g/dL and an absolute eosinophil count 2.1. Serological work-up notable for anti-neutrophil antibody level + 1:40 in an equivocal pattern, normal C3 and C4, hepatitis B/C and anti-PLA2R antibody negative, free kappa lambda ratio 1.01, and serum immunofixation electrophoresis showing a faint IgG kappa. Further workup showed elevated serum IgG4 level 377 mg/dL (normal 4.0-86.0 mg/dL). Imaging demonstrated mediastinal and retroperitoneal lymphadenopathy with normal-sized kidneys. She underwent a native kidney biopsy which showed membranous glomerulopathy, PLA2R negative, basement membrane IgG4 staining by paraffin immunohistochemistry, small subepithelial electron-dense deposits with minimal to mild interstitial fibrosis, and tubular atrophy. She was treated with rituximab 1000 mg 2 weeks apart and a follow-up dose of 1000 mg in 6 months. Repeat imaging showed decreased size of lymphadenopathy. Follow up labs 3 months from last rituximab dose showed BUN 10 mg/dL, Cr 0.75 mg/dL, Alb 3.2 g/dL and urine protein/creatinine ratio of 0.3g/g.
Discussion
IgG4-related MN disease is an extremely rare disease entity. The standard treatment option is high-dose prednisone. We opted for steroid-sparing therapy due to patient preference and history of osteopenia. There is limited data on the use of anti-CD 20 blockade for the treatment of IgG4-related MN. We demonstrate in this case that Rituximab, as dosed per the Mentor trial, is an effective treatment option for IgG4-related MN.