Serum AQP4-IgG level is associated with the phenotype of the first attack in neuromyelitis optica spectrum disorders.

We aimed in this study to elucidate the impact of serum AQP4-IgG titer before starting treatments to the clinical manifestation of neuromyelitis optica spectrum disorders (NMOSD). Serum titer at the onset, measured using live cell-based assay method, did not correlate to the subsequent relapse rate or neurological prognosis. Patients with optic neuritis as the first attack showed significantly higher serum titer than patients with acute myelitis or area postrema syndrome, although the titer did not correlate to the visual prognosis. The result implies that the pathological mechanism of optic neuritis and acute myelitis could be different in NMOSD.