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Kidney Week

Abstract: TH-PO563

Unusual Presentation of Proliferative Glomerulonephritis with Monoclonal Immunoglobulin Deposits (PGNMID)

Session Information

Category: Glomerular Diseases

  • 1401 Glomerular Diseases: From Inflammation to Fibrosis

Authors

  • Banach, Christopher T., Lehigh Valley Health Network, Allentown, Pennsylvania, United States
  • Goli, Kiran M., Lehigh Valley Health Network, Allentown, Pennsylvania, United States
  • Vaidya, Preyas, Lehigh Valley Health Network, Allentown, Pennsylvania, United States
  • Olaso, Aedan, Valley Kidney Specialists PC, Allentown, Pennsylvania, United States
  • Markowitz, Glen S., Columbia University Irving Medical Center, New York, New York, United States
Introduction

Proliferative glomerulonephritis with monoclonal immunoglobulin deposits (PGNMID) is a recent entity of monoclonal gammopathy of renal significance (MGRS) due to monoclonal immunoglobulin (mIg) deposits in the glomerulus leading to kidney injury. However, clinical or laboratory evidence of cryoglobulinemia needs to be ruled out. We describe a unique case of PGNMID with pathologically similar to infection related GN but with laboratory evidence of positive type II cryoglobulinemia and anti-smooth muscle antibodies.

Case Description

A 29-year-old obese male with hypertension and type 2 DM was admitted for AKI in the setting of nausea, vomiting, diarrhea & NSAID use. Creatinine (Cr) was 2.5 mg/dl with a baseline of 0.9 mg/dl. He received IV hydration and Cr improved to 1.8-1.9 mg/dl. However, further work up revealed microscopic hematuria & nephrotic syndrome with UPCR of 10 g/g. Serologic workup revealed positive ANA (1: 160). SPEP did not show monoclonal protein spike. Type II cryoglobulin with monoclonal IgG lambda and polyclonal IgG with a titer of 20 mg/dL was detected. Kidney biopsy showed PGNMID with monotypic IgG3-lambda shaped subepithelial deposits concerning for “infection-related glomerulonephritis”. Extensive infectious workup was negative. Hematologic evaluation did not reveal an underlying lymphoproliferative disorder. Rheumatologic workup showed elevated anti smooth muscle antibody (1:320). After 2 weeks, proteinuria improved significantly to 1.9 g/g but Cr increased to 2.3 mg/dl with persistent microscopic hematuria. Patient was then started on Prednisone 1 mg/kg. Cr improved to 2.0 mg/dl and UPCR 0.6 g/g after about 1 week of high dose steroids. He is doing better clinically but microscopic hematuria persists.

Discussion

We describe a unique case with pathologic evidence of PGNMID with subepithelial hump deposits suggestive of infection, monotypic composition of the deposits (IgG3-lambda) suggestive of possible underlying dysproteinemia but also with laboratory evidence of mixed cryoglobulinemia which also raises the possibility of an unusual pattern of cryoglobulinemic GN. Interestingly, anti-smooth muscle antibodies are also positive which raises a suspicion of sub clinical autoimmune hepatitis which can be associated with mixed cryoglobulinemia. This case emphasizes the importance of a thorough serologic workup, despite having biopsy results.