Abstract: SA-PO0739
IgM-Dominant Glomerulonephritis Unmasking Seronegative Rheumatoid Arthritis
Session Information
- Glomerular Diseases: Complement-Mediated Glomerulopathies and Infection-Related GN
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
- Cara, Anila, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Vargas-Brochero, Maria J., Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Laxamana, Trisha D., Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Juanet, Cristián, Mayo Clinic Minnesota, Rochester, Minnesota, United States
- Zand, Ladan, Mayo Clinic Minnesota, Rochester, Minnesota, United States
Introduction
IgM-dominant immune complex glomerulonephritis is a pattern of injury that requires evaluation for an underlying systemic process.
Case Description
A 74-year-old man with long-standing type 1 diabetes mellitus with severe peripheral vascular disease and prior history of osteomyelitis and left BKA presented with worsening proteinuria (1.5 g/g from a baseline of 0.5 g/g on UPCR), microscopic hematuria (3-10 RBC/HPF), and systemic symptoms including weight loss, anemia, and polyarthralgia. Creatinine was stable at baseline of 0.95 mg/dL.
ESR and CRP were elevated at 93 mm/h and 50 mg/L respectively. Blood cultures, hepatitis B and C were negative. Serologic workup was positive for ANA, but anti-ds-DNA, and antibodies to extractable nuclear antigen were negative. Complements were normal. Serum protein electrophoresis showed an IgG lambda monoclonal spike, but bone marrow biopsy revealed no plasma cell dyscrasia.
Kidney biopsy demonstrated polytypic IgM-dominant immune complex glomerulonephritis with mesangial deposits and coexisting diabetic nephropathy. Given clinical suspicion for a systemic process, further evaluation with PET-CT revealed inflammatory polyarthritis in small joints and hand x-ray confirmed erosive changes.
Testing for rheumatoid factor and anti-CCP were negative. The patient was seen in rheumatology and based on clinical findings on exam and imaging was diagnosed with seronegative rheumatoid arthritis. Given the concern for risk of infection in the setting of prior infection, patient was starting on abatacept (soluble CTLA4-Ig fusion protein) subcutaneous weekly injection for treatment.
Discussion
In patients presenting with immune complex glomerulonephritis, a search for an underlying cause including infection and autoimmune disease is essential to ensure accurate diagnosis and appropriate therapy.