Abstract
Granulomatosis with polyangitis (GPA) is difficult to diagnose in an early stage and when limited to the head and neck legion. Although PR3-ANCA is a useful biomarker for diagnosis, a negative value could not neglect the disease. Recently, it has been shown that a capture technique for analysis of ANCA can detect some ELISA and IIF negative GPA patients. In the present study, we examined the usefulness of capture ELISA for the diagnosis of GPA. We also described 2 cases of otits media without ANCA elevation, but strongly suspected GPA from the clinical course.
Case 1 is 75-year-old man who complained of right otorrhea and otalgia. Treatment for otitis media with systemic antibiotics was not effective and mastoidectomy was then performed. Histological examinations of granulomatous tissue in the mastoid showed non-specific granulomatous inflammation. One month after operation, the patient developed paralysis of the abducens nerve (VI), glossopharyngeal (IX), hypoglossal (XII) nerves on the right side and bilatelar hearing loss. We clinically diagnosed the case as a limited form (E alone) of probable GPA with the middle ear as the primary site.
Case 2 is 63 year-old female who complained of bilateral hearing loss and otorrhea. Treatment with systemic antibiotics was not effective. The patient developed left facial palsy. An ear CT showed that both upper tympanic cavity filled with soft tissue density. MRI revealed the presence of meningeal thickening. We clinically diagnosed the case as a limited form (E alone) of probable GPA.
Plasma samples from 9 patients who receive maintenance drug therapy in out-patient clinic were tested for the presence of PR3-ANCA with two detection methods (direct-ELISA and capture ELISA). One of 9 patients (11.1%) was PR3-ANCA positive in direct-ELISA, while 3 of 9 patients (33.3%) was positive in capture ELISA. This finding suggested that capture ELISA technique might become a useful test for the diagnosis of GPA.
