Neutrophil extracellular trap formation and deoxyribonuclease I activity in patients with otitis media with antineutrophil cytoplasmic antibody-associated vasculitis

No previous studies focused on the degradation of neutrophil extracellular traps (NETs) or deoxyribonuclease (DNase) I activity in the pathogenesis of otitis media with antineutrophil cytoplasmic antibody-associated vasculitis (OMAAV). The aim of this study was to explore the formation and degradation of NETs in the middle ear of patients with OMAAV during the onset and remission phases of the disease, with a particular focus on the relationships between the quantifiable NETs levels and DNase I activity. OMAAV patients were eligible for inclusion. Patients with otitis media with effusion (OME) were examined as controls. The levels of cell-free deoxyribonucleic acid (DNA), citrullinated-histone H3 (cit-H3)-DNA complex and myeloperoxidase (MPO)-DNA complex were quantified using an enzyme-linked immunosorbent assay. DNase I activity was measured using a fluorometric method. The quantifiable levels of cell-free DNA, cit-H3-DNA complex and MPO-DNA complex in the middle ear lavage of patients with OMAAV at onset were significantly higher than those in patients with OMAAV at remission and in patients with OME. DNase I activity in the patients with OMAAV at onset was significantly lower than those in patients with OMAAV at remission and OME, and was negatively correlated with the level of MPO-DNA complex. This study suggests that excessive NET formation and impaired DNase I activity are involved in the pathogenesis of OMAAV. NETs and DNase I activity may be useful biomarkers for the diagnosis and disease activity of OMAAV.