An Autopsy Case of Myeloperoxidase-anti-neutrophil Cytoplasmic Antibody (MPO-ANCA)-associated Vasculitis Accompanied by Cryoglobulinemic Vasculitis Affecting the Kidneys, Skin, and Gastrointestinal Tract

Abstract

Anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and cryoglobulinemic vasculitis (CV) rarely coexist. An 83-year-old woman was admitted with rapidly progressive renal failure, gastrointestinal hemorrhage and purpura with myeloperoxidase (MPO)-ANCA positivity and cryoglobulinemia. Despite intensive immunosuppressive treatment, she died of aspergillus pneumonia. Autopsy revealed necrotizing crescentic glomerulitis in the majority of the glomeruli, accompanied by partially membranoproliferative-like glomerular changes. Immunofluorescence staining revealed the presence of neutrophil extracellular trap (NET) formation in the glomeruli and cutaneous arteries. These pathological findings suggested that MPO-AAV and/or CV caused NET formation, leading to lethal systemic vasculitis.

Involvement of neutrophil extracellular traps in the pathogenesis of glomerulonephritis in a case of systemic lupus erythematosus and antineutrophil cytoplasmic antibody-associated vasculitis overlap syndrome

“…To clarify the involvement of NETs in the pathogenesis of renal damage, we investigated the deposition of NETs in the patient’s renal tissue. Immunofluorescence analyses were performed as previously reported [ 7 ]. In brief, citrullinated histone H3 (Cit-H3) was stained using anti-Cit-H3 antibody (Abcam, ab5103); DNA, using 4′6-diamidino-2-phenylindole (DAPI; Sigma-Aldrich, St. Louis, MO); and MPO, using anti-MPO antibody (R&D Systems, AF3776) to visualize NETs.…”