Antineutrophil Cytoplasmic Antibodies Induce Reactive Oxygen-Dependent Dysregulation of Primed Neutrophil Apoptosis and Clearance by Macrophages

Abstract

This study assessed whether anti-neutrophil cytoplasmic antibodies (ANCAs) interfere with the safe deletion of neutrophils by apoptosis and phagocytic clearance. Tumor necrosis factor (TNF)-primed neutrophils were incubated with normal IgG (N IgG) or ANCA IgG for up to 36 hours. Compared with N IgG, ANCAs accelerated constitutive apoptosis of TNF-␣ primed neutrophils, as assessed by morphology and confirmed by DNA laddering pattern on gel electrophoresis, and accelerated progression to secondary necrosis. The accelerated apoptosis induced by ANCA was dependent on reactive oxygen species generation, as primed neutrophils from patients with chronic granulomatous disease failed to show an effect of ANCAs on apoptosis. However, there was no change in the rate at which neutrophils exhibited annexin V binding, indicating that externalization of phosphatidylserine was not accelerated by ANCAs. Furthermore, when ANCA-treated primed neutrophils were interacted with human or murine peritoneal macrophages after 12 hours there was significantly less phagocytosis by human macrophages and no difference in phagocytosis by murine peritoneal-derived macrophages when compared with N IgG-treated controls. In conclusion, ANCAs accelerate apoptosis and secondary necrosis in TNF-primed neutrophils by a mechanism dependent on the generation of reactive oxygen species, with uncoupling of nuclear and surface membrane changes, resulting in a "reduced window of opportunity" for phagocytic recognition and engulfment before disintegration. (Am J Pathol 2000, 157:211-220)

Dendritic cell uptake of human apoptotic and necrotic neutrophils inhibits CD40, CD80, and CD86 expression and reduces allogeneic T cell responses: Relevance to systemic vasculitis

“…The data also did not support the contention that ANCAs may help perpetuate an immune response through their previously demonstrated effects on accelerating neutrophil apoptosis. ANCAs induce accelerated and dysregulated apoptosis of TNF␣-primed neutrophils, resulting in a reduced likelihood of recognition and phagocytosis by macrophages before disintegration through secondary necrosis (30). However, uptake of secondarily necrotic neutrophils by DCs led to a reduced, not enhanced, capacity of DCs to stimulate an MLR.…”

“…Neutrophils were cultured at 37 o C for 18 hours, after which 80 Ϯ 1.4% of the cells (mean Ϯ SEM) were apoptotic as assessed by morphologic analysis using Jenner-Giemsa (BDH, Poole, UK) staining of cytospins. Apoptosis was confirmed by staining for annexin V (30,34). Fewer than 5% of cells were necrotic as assessed by trypan blue dye exclusion and propidium iodide incorporation.…”

“…Ligation of PR3 and MPO on primed neutrophils induces neutrophil activation, with a respiratory burst and release of granule contents (27), factors that promote endothelial damage (28,29). ANCAs also induce accelerated and dysregulated apoptosis of TNF␣-primed neutrophils, resulting in a "reduced window of opportunity" for recognition and phagocytosis by macrophages before disintegration (30).…”

Different Quantitative Apoptotic Traits in Coronary Atherosclerotic Plaques From Patients With Stable Angina Pectoris and Acute Coronary Syndromes

“…Furthermore, apoptotic cells can amplify local inflammatory processes as a result of secondary necrosis. 6,7 Recent studies showed that all apoptotic cells within plaques such as lymphocytes, monocytes, and smooth muscle and endothelial cells may acquire procoagulant potential, 8 -10 probably by activating tissue factor 11 after the exposure to phosphatidylserine inside the exoplasmic leaflet of the plasma membrane. Furthermore, membrane microparticles shed by fragmented apoptotic cells also have procoagulant properties.…”

Febrile temperatures control antineutrophil cytoplasmic autoantibody–induced neutrophil activation via inhibition of phosphatidylinositol 3‐kinase/Akt

“…For example, heat-accelerated apoptosis could result in proinflammatory removal of apoptotic neutrophils, particularly when these apoptotic cells become opsonized with ANCAs (30)(31)(32). However, other investigators have found that, based on observations in animal and human studies, fever is beneficial in host defense reactions, and also that antipyretic treatment interferes with this effect (19)(20)(21)33).…”