Abstract
BackgroundRenal involvement is a common and severe complication of ANCA (antineutrophil cytoplasmic antibody) associated vasculitis (AAV) potentially resulting in a pauci-immune necrotizing and crescentic antineutrophil cytoplasmic antibody (ANCA) glomerulonephritis (GN) with acute kidney injury (AKI), end-stage renal disease (ESRD) or death. We recently described that Bowman’s capsule rupture links glomerular damage to tubulointerstitial inflammation in ANCA-associated glomerulonephritis. Herein we provide a comprehensive histological subtyping of immune cell infiltrates in association with Bowman’s capsule rupture in ANCA GN.MethodsA total of 44 kidney biopsies with ANCA GN were retrospectively included in a single-center observational study. Within a renal biopsy specimen, each glomerulus was scored separately for the presence of extensive and focal Bowman’s capsule rupture in injured glomeruli. Infiltrates of neutrophils, eosinophils, plasma cells, and mononucleated cells (macrophages, lymphocytes) were quantified as a fraction of the area of total cortical inflammation.ResultsExtensive Bowman’s capsule rupture was associated with tubulointerstitial inflammation containing infiltrates of neutrophils, eosinophils and plasma cells. A similar association was observed for the presence of focal Bowman’s capsule rupture, correlating with tubulointerstitial inflammation containing neutrophils, eosinophils and plasma cells. Multiple logistic regression confirmed that extensive Bowman’s capsule rupture correlated with tubulointerstitial inflammation containing neutrophils, and focal Bowman’s capsule rupture correlated with neutrophil and plasma cell infiltration. Furthermore, this association was specifically observed in PR3-ANCA GN.ConclusionTo our knowledge, this is the first report linking Bowman’s capsule rupture directly to tubulointerstitial inflammation by immune cell subtypes. This underscores a pathomechanistic link between tubulointerstitial and glomerular lesions in ANCA GN and needs further investigation.Graphical abstract
Highlights
Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a small vessel vasculitis according to the 2012 revised Chapel Hill Consensus Conference Nomenclature of Vasculitides, most frequently presenting as microscopic polyangiitis (MPA) or granulomatosis with polyangiitis (GPA) [1, 2]
Renal involvement is a common and severe complication of AAV potentially resulting in pauci-immune necrotizing and crescentic antineutrophil cytoplasmic antibody (ANCA) glomerulonephritis (GN) with acute kidney injury (AKI), end-stage renal disease (ESRD) or death [2]
Clinicopathologic studies of the European Vasculitis Study Group (EUVAS) demonstrated that distinct glomerular lesions are related to renal outcome in ANCA GN [3,4,5,6]
Summary
Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a small vessel vasculitis according to the 2012 revised Chapel Hill Consensus Conference Nomenclature of Vasculitides, most frequently presenting as microscopic polyangiitis (MPA) or granulomatosis with polyangiitis (GPA) [1, 2]. We provide comprehensive histological subtyping of immune cell infiltrates in association with extensive or focal Bowman’s capsule rupture in a cohort of 44 patients with ANCA GN confirmed by renal biopsy. Renal involvement is a common and severe complication of ANCA (antineutrophil cytoplasmic antibody) associated vasculitis (AAV) potentially resulting in a pauci-immune necrotizing and crescentic antineutrophil cytoplasmic antibody (ANCA) glomerulonephritis (GN) with acute kidney injury (AKI), end-stage renal disease (ESRD) or death. Multiple logistic regression confirmed that extensive Bowman’s capsule rupture correlated with tubulointerstitial inflammation containing neutrophils, and focal Bowman’s capsule rupture correlated with neutrophil and plasma cell infiltration. This association was observed in PR3-ANCA GN. This underscores a pathomechanistic link between tubulointerstitial and glomerular lesions in ANCA GN and needs further investigation
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