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Kidney Week

Abstract: TH-PO685

"Atypical" Atypical Anti-Glomerular Basement Disease

Session Information

Category: Glomerular Diseases

  • 1402 Glomerular Diseases: Clinical, Outcomes, and Trials

Authors

  • Shringi, Sandipan, Brown University Warren Alpert Medical School, Providence, Rhode Island, United States
  • Henriksen, Kammi J., University of Chicago Department of Pathology, Chicago, Illinois, United States
  • Shah, Ankur, Brown University Warren Alpert Medical School, Providence, Rhode Island, United States
Introduction

Anti-glomerular basement membrane (anti-GBM) disease frequently presents as rapidly progressive glomerulonephritis due to autoantibodies directed toward the alpha 3 NC 1 domain of type IV collagen, found in the glomerular and alveolar basement membrane. In atypical anti-GBM disease, serum antibodies are negative, but the biopsy shows linear IgG staining. Clinically, it presents with an indolent renal limited course and good prognosis.

Case Description

A 36-year-old woman with a history of HIV, hypertension, diabetes mellitus type 2, asthma, obesity, and fatty liver presented with elevated creatinine, hematuria, and proteinuria. She developed foamy and dark urine six months before referral. HIV was stable with an undetectable viral load, CD 4 count 190 cells/mm3 on dolutegravir-rilpivirine. Physical examination was unremarkable. Presentation labs were BUN 34, sCr 1.91 mg/dL, urinalysis with 3+ blood, 100 protein, albuminuria 3087mg/g. C3 143mg/dl, C4 28 mg/dl, and serologies included negative ANCA, MPO, PR3, and anti-GBM. Kidney biopsy demonstrated an active necrotizing and crescentic glomerulonephritis involving 36% of the sampled glomeruli, as well as older fibrous crescents in 27% of the glomeruli. There was patchy interstitial nephritis and mild interstitial fibrosis and tubular atrophy. Direct immunofluorescence demonstrated linear staining of the GBMs for IgG (3+) and kappa (2-3+) and lambda (3+) light chains. There were no electron-dense deposits by electron microscopy. The patient was started on treatment with solumedrol and cyclophosphamide. After the development of diffuse alveolar hemorrhage, 6 sessions of plasmapheresis were performed. sCr peaked at 3.6 with improvement to 2.2 since. ESR/CRP were used as surrogates of disease activity, owing to the lack of ability to monitor antibody titers.

Discussion

Atypical GBM was thought to have an indolent disease course without crescent formation on light microscopy, but more recent literature has shown crescents in pathology and progression to ESKD. Diffuse alveolar hemorrhage has not been reported to our knowledge. Management of atypical anti-GBM is complicated, owing to the lack of ability to monitor serum levels of antibodies. It is important for treating clinicians to be aware of the evolving landscape of this entity and of the difficulties in treatment including decisions regarding plasmapheresis and methods to monitor disease activity.