Abstract: SA-PO0792
Cryoglobulinemic Glomerulonephritis (GN) Masquerading as Drug-Induced Lupus Nephritis: A Biopsy That Changed Management
Session Information
- Glomerular Diseases: Lupus Nephritis, Monoclonal Gammopathy-Related Disease, and Transplantation
October 24, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- McCoy, Ian P., West Virginia University, Morgantown, West Virginia, United States
- Kaushal, Amit, West Virginia University, Morgantown, West Virginia, United States
- Shahzad, Sheikh Raza, West Virginia University, Morgantown, West Virginia, United States
- Tomar, Ojaswi Singh, West Virginia University, Morgantown, West Virginia, United States
Introduction
Cryoglobulinemic glomerulonephritis is classically HCV-associated. HCV-negative type II disease is less common and biopsy features can mimic drug-induced lupus nephritis. We report a case of HCV-negative type II cryoglobulinemia with cutaneous, pulmonary, and renal involvement, where biopsy clarified the diagnosis and rituximab achieved sustained remission.
Case Description
A 66-year-old male on hydralazine presented with hemoptysis, dyspnea, leg rash, and AKI (creatinine 1.96 mg/dL, baseline 1.0-1.3 mg/dl). Skin biopsy showed leukocytoclastic vasculitis. Workup revealed type II cryoglobulinemia (monoclonal IgM kappa, polyclonal IgG), rheumatoid factor 69 IU/mL, profound hypocomplementemia (C4 <1 mg/dL, C3 70 mg/dL, CH50 <10 U/mL). ANA, ANCA, anti-GBM, hepatitis B/C, HIV, and SPEP/UPEP were negative. UPCR was 1,553 mg/g with microscopic hematuria. Kidney biopsy showed endocapillary and mesangial hypercellularity, granular IgG/IgM on IF, subendothelial/mesangial deposits, and prominent intracapillary CD68-positive monocytes consistent with mixed cryoglobulinemic GN. He received intravenous methylprednisolone with oral prednisone taper and rituximab induction: 1 g x 2 doses, two weeks apart. Respiratory failure resolved, the rash cleared, and creatinine stabilized at 1.49 mg/dL. At five months of induction alone, complements normalized, urinalysis cleared, and cryoglobulins were trace; maintenance rituximab followed at seven months.
Discussion
Type II cryoglobulinemia used to be largely a complication of hepatitis C, but with widespread HCV cure, HCV-negative cases are now more visible. This shift makes a careful search for secondary causes essential, particularly lymphoproliferative and autoimmune disorders. Kidney biopsy is essential to confirm the diagnosis. Cryoglobulinemic GN can look like drug-induced lupus nephritis, especially on hydralazine. In this case, while the patient's hydralazine use strongly suggested drug-induced lupus, PAS-positive intracapillary pseudothrombi and CD68+ monocytes on biopsy shifted treatment toward rituximab rather than drug withdrawal alone. Rituximab induction alone produced sustained remission of the renal, pulmonary, and cutaneous involvement.