Otitis media with ANCA associated vasculitis (OMAAV) : Clinical differences according to ANCAs, serological study of ANCA negative AAV

Objective: Otitis media with ANCA (antineutrophil cytoplasmic antibody) associated vasculitis (OMAAV) is intractable conditions that are resistant to conventional conservative treatment. In the present study, we examined the clinical differences according to ANCA subtype and the serological study of ANCA negative patients were performed.<br>Methods: A total of 297 patients were enrolled in the nationwide surveys. Patients were divided into three groups: PR3-ANCA positive group 67 (23%), MPO-ANCA positive group 159 (54%) and ANCA double negative group 52 (17%). ANCA double positive 15 (5%) and ANCA unmeasured patients 4 (1%) were excluded. Clinical data were collected and compared among the three groups. <br>Plasma sample of ANCA negative AAV patients were tested for the presence of ANCA with 5 detection methods (3 PR3-ANCA kits (direct-ELISA, capture ELISA, anchor ELISA), 2 MPO-ANCA kits (direct-ELISA, capture ELISA) and Indirect immunofluorescence (IIF) technique. The other ANCA serotype (azurocidin, BPI, capthepsin G, elastase, lactoferrin, lysozyme) were also tested by ELISA technique.<br>Results: No significant differences among groups were found in the clinical otological findings and the major clinical symptoms on the initial visit. Over the whole course of the follow-up period, PR3-ANCA positive group had significantly higher rate of the nose involvement and the lung involvement, while ANCA negative group had significantly higher rate of hypertrophic pachymeningitis. Rate of relapes was significantly higher in PR3-ANCA positive group.<br>Of 16 cliniacally ANCA negative patients, 1 patient was positive for PR3-ANCA and 3 were positive for MPO-ANCA with combined ELISA methods. Two patients were positive for P-ANCA in IIF. Furthermore, 1 patient was positive for BPI-ANCA and one was positive for elastase-ANCA.<br>Conclusion: Over the course of the follow-up period, PR3-ANCA positive group had significant higher rate of nose and lung involvement, and had a higher rate of relapse. ANCA negative group had significantly higher rate of hypertrophic pachymeningitis. These findings may allow for better characterization of pathologies and eventually assist in improving the clinical utility of OMAAV diagnostic criteria. To the ANCA negative cases, ANCA should also be tested by a different technique such as new generation ELISA and IIF. Additionally, presence of other ANCA serotype should also be considered.