Abstract: PO1739
Recurrence of Anti-GBM Disease: An Epiphenomenon?
Session Information
- Glomerular Diseases: Vasculitis and TMA
October 22, 2020 | Location: On-Demand
Abstract Time: 10:00 AM - 12:00 PM
Category: Trainee Case Report
- 1202 Glomerular Diseases: Immunology and Inflammation
Authors
- Guntupalli, Sri Vibhavari, Saint Vincent Hospital, Worcester, Massachusetts, United States
- Black, Robert Mark, Saint Vincent Hospital, Worcester, Massachusetts, United States
Introduction
The simultaneous presentation of anti-GBM antibodies with ANCA-associated glomerulonephritis occurs in about 40% of individuals with anti-GBM disease. However, recurrence of anti-GBM disease is rare. We report a case of relapsing disease where the recurrent anti-GBM may have been caused by the ANCA-induced glomerular injury.
Case Description
A 62-year-old woman presented with generalized weakness and arthralgia. Creatinine was elevated to 1.7 mg/dL from 0.8 mg/dL, urinalysis showed 3+ blood and 1+ protein with dysmorphic RBCs. Her serologies showed an elevated anti-MPO and a moderately high anti-GBM titre. Her renal biopsy revealed crescentic glomerulonephritis with segmental linear IgG staining of the glomerular basement membrane on immunofluorescence. In 2015, at the time of her presentation, she was treated with plasmapheresis, cyclophosphamide and maintained on tapering doses of azathioprine and prednisone. In 2017, as her immunosuppression was tapered, her Pcr rose, her urine showed RBCs and her anti-GBM titer, which had been undetectable each month, again became positive. She was retreated with a similar regimen. In 2019, she had another relapse with a higher ANCA titer, a mild rise in creatinine and hematuria. Her anti-GBM, by comparison, remained negative. Her repeat renal biopsy was consistent with vasculitis, but the immunofluorescence at this time was negative. She was treated with an escalated steroid dose and with rituximab. She appears to be in clinical and laboratory remission at this time with a persistently negative anti-GBM, but with continued anti-MPO positivity. A re-review of her initial biopsy showed that there was linear staining, but it was discontinuous and segmental.
Discussion
On initial presentation, this patient appeared to have anti-GBM disease with concomitant ANCA positivity, a not uncommon combination. Both titers rose with her first relapse. However, during her second recurrence she was noted to have an elevated ANCA with necrotizing vasculitis and was promptly treated. At that time, her anti-GBM remained negative. We suggest that this patient has an ANCA-positive vasculitis and that the anti-GBM may have been a secondary or epiphenomenon due to release of GBM antigens as a result of glomerular damage by anti-MPO antibodies [1]. We believe that this might explain the unusual recurrence of anti-GBM serology in this patient.