Objective: The purpose was to explore the presence of myeloperoxidase (MPO)-deoxyribonucleic acid (DNA) complex as a surrogate marker of neutrophil extracellular traps (NETs) in the middle ear fluid, and to clarify the correlation between its quantifiable level and hearing outcome in patients with otitis media associated with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV).
Study design: Prospective study.
Setting: Tertiary referral center.
Patients: Nine AAV patients presenting with otitis media.
Intervention: Collection of the fluid samples from middle ear.
Main outcome measure: The quantifiable levels of MPO-DNA complex using an enzyme-linked immunosorbent assay.
Results: The quantifiable levels of MPO-DNA complex in patients with AAV were significantly higher than those in controls (p < 0.001). In particular, both ANCA-positive and -negative cases indicated higher levels of MPO-DNA complex compared with the controls (p = 0.004 and p = 0.006, respectively). The significant negative correlations were observed between the level of MPO-DNA complex and the functional hearing values for air (r = -0.82, p = 0.009) and bone conduction (r = -0.73, p = 0.028), respectively.
Conclusion: This analysis is the first to reveal the presence of elevated levels of MPO-DNA complex in the middle ear fluid, suggesting the pathogenic role of NETs in otitis media associated with AAV. NETs may be a valuable biomarker for use in clinical decision-making and predicting hearing outcome, regardless of ANCA status.