The Diagnostic and Clinical Utility of the Myeloperoxidase–DNA Complex as a Biomarker in Otitis Media With Antineutrophil Cytoplasmic Antibody-associated Vasculitis

<jats:sec> <jats:title>Objective:</jats:title> <jats:p>This prospective study aimed to evaluate the diagnostic and clinical utility of the myeloperoxidase (MPO)–DNA complex as a NETosis-derived product in the middle ear fluid of patients with otitis media with antineutrophil cytoplasmic antibody-associated vasculitis (OMAAV).</jats:p> </jats:sec> <jats:sec> <jats:title>Study Design:</jats:title> <jats:p>Prospective study.</jats:p> </jats:sec> <jats:sec> <jats:title>Setting:</jats:title> <jats:p>Tertiary referral center.</jats:p> </jats:sec> <jats:sec> <jats:title>Patients:</jats:title> <jats:p>Twenty-two patients diagnosed with OMAAV.</jats:p> </jats:sec> <jats:sec> <jats:title>Intervention:</jats:title> <jats:p>Collection of the fluid samples from middle ear.</jats:p> </jats:sec> <jats:sec> <jats:title>Main Outcome Measure:</jats:title> <jats:p>The levels of the MPO–DNA complex in the fluid samples were quantified using an enzyme-linked immunosorbent assay.</jats:p> </jats:sec> <jats:sec> <jats:title>Results:</jats:title> <jats:p>Patients with both systemic and localized forms of OMAAV showed significantly higher levels of the MPO–DNA complex compared to the controls (<jats:italic toggle="yes">p</jats:italic> < 0.001 and <jats:italic toggle="yes">p</jats:italic> = 0.002, respectively). In particular, they showed significantly higher levels of MPO–DNA complex compared to the controls, regardless of serum antineutrophil cytoplasmic antibody status (<jats:italic toggle="yes">p</jats:italic> < 0.001 and <jats:italic toggle="yes">p</jats:italic> < 0.001, respectively) or immunosuppressive therapy (<jats:italic toggle="yes">p</jats:italic> < 0.001 and <jats:italic toggle="yes">p</jats:italic> < 0.001, respectively) at the time of sampling. An optical density cutoff value of 0.16 at 405 nm according to the receiver operating characteristic curve showed a sensitivity of 86.4%, specificity of 95.5%, positive predictive value of 95.0% and negative predictive value of 87.5% for the diagnosis of OMAAV. Significant positive correlations were observed between the levels of MPO–DNA complex and the values for air conduction – (<jats:italic toggle="yes">r</jats:italic> = 0.49, <jats:italic toggle="yes">p</jats:italic> = 0.022) and bone conduction – pure tone average thresholds (<jats:italic toggle="yes">r</jats:italic> = 0.45, <jats:italic toggle="yes">p</jats:italic> = 0.035).</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusions:</jats:title> <jats:p>The detection and quantification of the MPO–DNA complex in the otitis media fluid may aid in providing a definite diagnosis as well as predicting the activity and severity of OMAAV.</jats:p> </jats:sec>