Kidney Histological Findings in a Patient Triple Seropositive for Myeloperoxidase and Proteinase 3 Antineutrophil Cytoplasmic Antibodies and Anti-Glomerular Basement Membrane Antibody: A Rare Case Report

Résumé fourni par la source

We examined a kidney biopsy from an 83-year-old woman with rapidly progressive renal failure who tested positive for anti-GBM antibody, MPO-ANCA, and PR3-ANCA. Of the 50 obtained glomeruli, 40 showed acute-phase necrotizing glomerulitis with fibrin deposition. Five glomeruli showed fibrocellular crescent formation, and the remaining five showed chronic changes with global sclerosis. Very small necrotizing vasculitis was observed in the small arteries. Widespread tubulointerstitial nephritis was observed. The high incidence of acute-phase lesions in this case can be explained by anti-GBM glomerulonephritis. However, the coexistence of the latter chronic lesions suggests the involvement of MPO- and PR3-ANCA-associated vasculitis. After steroid pulse therapy followed by the tapering oral prednisolone, hemodialysis was initiated, and the serologic remission of anti-GBM antibodies and ANCAs was achieved without additional immunosuppression. However, febrile relapse with a re-elevation of anti-GBM antibody and myeloperoxidase-ANCA levels occurred 18 months after steroid discontinuation and she promptly responded to reintroduction of low-dose prednisolone, with no further recurrence. Together with the biopsy findings of acute anti-GBM-type necrotizing glomerulitis superimposed on lesions suggestive of ANCA-associated vasculitis, this course supports overlapping pathogenic mechanisms in triple-seropositive disease and underscores the need for long-term clinical and serologic follow-up even after apparent remission.

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