Abstract: FR-PO620
ANCA Glomerulonephritis With IgA Deposits
Session Information
- Glomerular Diseases: Lupus and Vasculitis
November 04, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1302 Glomerular Diseases: Immunology and Inflammation
Authors
- Zidan, Elena, Bridgeport Hospital Internal Medicine, Bridgeport, Connecticut, United States
- Dommu, Aaron M., Bridgeport Hospital, Bridgeport, Connecticut, United States
Introduction
We present a patient with antineutrophilic cytoplasmic antibody (ANCA) associated pauci-immune necrotizing crescentic glomerulonephritis (AAV) who was additionally found to have IgA deposits on immunofluorescence. Estimated prevalence of circulating ANCA in biopsy proven IgA nephropathy (IgAN) is approximately 1.4%. There are a limited number of cases in the literature of coexisting AAV and IgAN.
Case Description
A 36-year-old female from Peru presented to the hospital with gross hematuria and transient right third finger proximal interphalangeal joint arthritis. Physical exam was unremarkable and stable vital signs. On laboratory evaluation she was found to have kidney failure with serum creatinine of 1.7 mg/dL, no baseline labs available. Urinalysis revealed gross hematuria, and spot protein creatinine ratio revealed nephrotic range proteinuria 3.69 mg/mg Cr (normal <=0.10 mg/mg Cr) with serum albumin 2.7 mg/dL (normal 0.4-1.3 mg/dL). Further serology was remarkable for ANCA titer >1:1280 (normal <1:20) with perinuclear pattern, elevated anti-myeloperoxidase antibody 570.7 (normal <1.0 AI). Anti-glomerular basement membrane and proteinase-3 antibodies were undetectable. Ultrasound guided right renal biopsy was performed after she was started empirically on pulse dose methylprednisolone. Renal biopsy revealed pauci-immune necrotizing crescentic glomerulonephritis and immunofluorescence showed concomitant mesangial IgA deposits. After initial three doses of pulse steroid, she was transitioned to high dose oral prednisone and two one-gram doses of rituximab (14 days apart), with full recovery of renal function. Gross hematuria persisted for 5 weeks after steroid initiation. Renal imaging was unremarkable.
Discussion
This is a unique case of AAV with concurrent mesangial IgA staining immune deposits, whereas typically, AAV is a pauci-immune process without significant staining on immunofluorescence. Persistent gross hematuria is unusual for ANCA GN and does raise suspicion that the IgA deposits may be clinically relevant. The clinical significance of the IgA staining in this case of AAV is unclear, as many kidney transplant donors without kidney disease have incidental IgA deposits. Alternatively, this may represent a form of crescentic glomerulonephritis where both ANCA and IgA contribute to pathogenesis. Fortunately, patient had an excellent response to course of steroids and rituximab, with normalization of renal function.