Abstract: PUB054
Masquerading IgG4 Disease or a Disease Caught in Evolution
Session Information
Category: Acute Kidney Injury
- 102 AKI: Clinical, Outcomes, and Trials
Authors
- Khan, Sobia N., Stony Brook University, Stony Brook, New York, United States
- Revelo Penafiel, Monica Patricia, University of Utah Health, Salt Lake City, Utah, United States
Introduction
IgG4-related disease (IgG4-RD), a systemic disease characterized by IgG4-positive plasma cells, storiform fibrosis, and tissue eosinophilia. We present a unique case of IgG4 disease which initially has acute interstitial nephritis on kidney biopsy.
Case Description
64-year-old male with hypertension presented for acute kidney injury. Vitals stable, takes bisoprolol-HCTZ daily. Na 129, K 3.2, BUN 41, SCr 3.2, +ANA, C3/C4 normal. Last known creatinine ~0.9. History revealed has completed Bactrim DS, 2 weeks ago, NSAIDs in past 2 months. Urinalysis: no hematuria, urine-protein to creatinine ratio ~500. SPEP/UPEP with M-spike. Immunofixation with IgG kappa monoclonal antibody. Bone marrow biopsy: 10-15% CD138 positive plasma cells, diagnosed with smoldering multiple myeloma. Native kidney biopsy revealed acute interstitial nephritis with mild interstitial fibrosis and tubular atrophy, diagnosis of acute interstitial nephritis was made with co-trimoxazole or NSAIDs being possible drug culprits. He was treated with Prednisone, acute kidney injury improved but developed residual chronic kidney disease with creatinine of 1.74. MM labs remained stable with no treatment planned.
Eight months later, readmitted with AKI and weight loss, repeat kidney biopsy: acute tubular damage, mixed interstitial inflammatory infiltrate with IgG4 positive plasma cell and obliterative arteriopathy consistent with IgG 4 mediated interstitial nephritis. Immunohistochemical stains for IgG4: aggregates of >10 IgG4 positive plasma cells. Serum Immunoglobulin: IgA 148, IgM 35, IgE 110, IgG 2530, normal complement level. CT/MRI of spine, lumbar region, and pelvis negative for cancer. Treated with prednisone and Rituximab.
Discussion
IgG4-RD, a fibroid inflammatory disorder. Pathogenesis unclear, thought to involve a persistent antigenic stimulus possibly from chronic infection triggering polyclonal expansion of B cells. These signals promote IgG 4 class switching, plasma cell expansion and local fibrotic response.
Our case is atypical as the general manifestations of IgG4-RD include lymphadenopathy and weight loss. Weight loss is a prominent symptom in patients with exocrine pancreatic insufficiency, but our patient only had kidney involvement. This case highlights the importance of including IgG4 disease in the differential diagnosis of acute kidney injury.