ASN's Mission

To create a world without kidney diseases, the ASN Alliance for Kidney Health elevates care by educating and informing, driving breakthroughs and innovation, and advocating for policies that create transformative changes in kidney medicine throughout the world.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005

email@asn-online.org

202-640-4660

The Latest on X

Kidney Week

Abstract: TH-PO721

Kidney Involvement in Cryoglobulinemia: Not Always Crystal Clear

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

  • Boddepalli, Raja S., Virginia Commonwealth University, Richmond, Virginia, United States
  • Alavala, Vishnupriya, Virginia Commonwealth University, Richmond, Virginia, United States
  • Cornell, Lynn D., Mayo Foundation for Medical Education and Research, Rochester, Minnesota, United States
  • Kidd, Jason M., Virginia Commonwealth University, Richmond, Virginia, United States

Group or Team Name

  • Virginia Commonwealth University.
Introduction

Cryocrystalglobulinemia (CCG) is a rare variant of type 1 cryoglobulinemia. Renal involvement is rare and associated with plasma cell dyscrasias. In CCG, monoclonal immunoglobulins assemble into crystalline arrays inciting inflammation and causing vasculopathy from pseudo thrombi in renal glomerular capillaries. We present a case of CCG due to monotypic IgG deposits with negative immunofixation (IFE).

Case Description

A 67-year-old male was referred for edema and proteinuria. On presentation, blood pressure was 136/87 mmHg and physical exam was significant for lower extremity edema. Laboratory studies revealed a creatinine of 2.5 mg/dl with no antecedent history of renal failure and spot urine protein to creatinine ratio (UPCR) was 2.5 g/g. Serum and urine IFE were negative. Kidney biopsy showed endocapillary proliferative macrophage-rich glomerulonephritis with intracapillary pseudo-thrombi, intracellular crystals, and monotypic IgG2 Kappa deposits. On electron microscopy, crystals were noted within infiltrating macrophages in glomerular capillary lumens consistent with CCG. (Figure 1) Bone marrow biopsy was unremarkable. He was treated with cyclophosphamide, bortezomib and dexamethasone. Proteinuria persisted and daratunamab was added and serum creatinine improved to 1.8 mg/dl and proteinuria completely resolved 8 months after his initial presentation

Discussion

Our case describes a rare variant of monoclonal gammopathy with renal significance (MGRS) without a detectable circulating monoclonal protein that responded to clone-directed therapy. Kidney biopsy should be pursued in patients with renal insufficiency and proteinuria without abnormal serologies.

Figure 1: Crystals noted within infiltrating macrophages in glomerular capillary lumens.