Abstract: SA-PO230
Proliferative Glomerulonephritis with Monoclonal IgG Deposits Leading to the Diagnosis of B Cell Lymphoma
Session Information
- Trainee Case Reports - V
October 27, 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
- Hanna, Wael A., Lehigh Valley Hospital, Breinigsville, Pennsylvania, United States
- D'Agati, Vivette D., Columbia University College of Physicians and Surgeons, New York, New York, United States
- Reichart, James P., Valley Kidney Specialists, Macungie, Pennsylvania, United States
Introduction
Proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) is a rare glomerular disease within the MGRS spectrum, first described in 2004. Membranoproliferative GN is the most common histologic pattern.
Case Description
A 70-year-old female with a history of mild hypertension (HTN) was referred for renal insufficiency and uncontrolled HTN. On examination, BP was 180/84 with otherwise normal cardiopulmonary exam and no edema. Lab data showed elevated S Cr of 1.9 mg/dL. Urinalysis displayed proteinuria and microhematuria with dysmorphic RBCs. The urine protein:Cr ratio was 1.9 g/g with serum albumin of 3.8 g/dL. CBC showed Hb of 11.6 g/dL with normal WBC count and differential. Serology for hepatitis, cryoglobulin, C3, C4, ANCA and anti-GBM antibody were negative. Serum immunofixation revealed IgM- kappa and IgM-lambda M-spikes with FLC kappa/lambda ratio of 2.2.
Renal biopsy showed diffuse endocapillary proliferative GN with membranoproliferative features. Immunofluorescence revealed mesangial and glomerular capillary wall staining for IgG, C3, C1q and kappa light chain, with restricted positivity for IgG subtype 3. EM displayed granular mesangial and subendothelial electron dense deposits. The findings were diagnostic of PGNMID with monoclonal IgG3-kappa deposits. Bone marrow biopsy showed (1%) kappa-restricted B cell lymphoma. She received four weekly doses of rituximab infusion after which she achieved clinical renal remission. Ten weeks after initiating rituximab, S Cr and UPCR had fallen to 1.3 mg/dL and 0.2 g/g respectively.
Discussion
PGNMID presents typically with nephrotic range proteinuria, renal insufficiency, hematuria and HTN and 20% of patients progress to ESRD. Only 20-30% of patients have a detectable M-protein in the serum or urine. The MIg detected in the serum may not be identical to the MIg in the kidney deposits, as shown in this case. Our case illustrates that an onconephrologic approach to detect and target the underlying B-cell clone can lead to clinical remission of PGNMID.