title: Utility of aquaporin-4 antibody assay in patients with neuromyelitis optica spectrum disorders.
abstract: OBJECTIVE
  Our aim was to evaluate the utility of aquaporin-4 antibodies (AQP4-Ab) in patients with neuromyelitis optica spectrum disorders (NMOSD).
  
  
  METHODS
  The clinical and radiological characteristics of 78 patients with NMOSD and 22 with multiple sclerosis (MS), who were tested for AQP4-Ab by a cell-based assay, were assessed.
  
  
  RESULTS
  The mean time interval between symptom onset and development of optic neuritis and myelitis was 39.9 months in neuromyelitis optica (NMO). About 40% of patients with limited NMO would have fulfilled the diagnostic criteria for MS in the absence of the antibody assay results. In patients with longitudinally extensive transverse myelitis, positive AQP4-Ab assay results were associated with the poor response to acute steroid treatment and asymptomatic visual evoked potential abnormality. Presence of either painful tonic spasm associated with myelitis or severe disability at onset had high specificity and relatively high sensitivity in differentiating NMOSD with AQP4-Ab from MS.
  
  
  CONCLUSIONS
  The AQP4-Ab assay can facilitate the early diagnosis of NMO and prevent limited NMO from being misdiagnosed as MS. It can predict the poor response to first-line acute-phase treatment and probably detect the subclinical optic nerve involvement in subgroups of NMOSD. Lastly, it will contribute to the upcoming revision of the current diagnostic criteria for NMO.
authors: Department of Neurology, Seoul National University, College of Medicine, Korea.
authors: Sung-Min
authors: SM
authors: Kim
authors: Patrick
authors: P
authors: Waters
authors: Mark
authors: M
authors: Woodhall
authors: Jee-Young
authors: JY
authors: Kim
authors: Jee-Eun
authors: JE
authors: Kim
authors: Ji Won
authors: JW
authors: Yang
authors: Jun-Soon
authors: JS
authors: Kim
authors: Jung-Joon
authors: JJ
authors: Sung
authors: Kyung Seok
authors: KS
authors: Park
authors: Kwang-Woo
authors: KW
authors: Lee
mesh_terms: D051401:Aquaporin 4 / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood*; D001921:Brain / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000175:diagnosis* / Q000276:immunology; D009471:Neuromyelitis Optica / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D012680:Sensitivity and Specificity
chemical_list: C496030:AQP4 protein, human; D051401:Aquaporin 4; D001323:Autoantibodies
keywords: Neuromyelitis optica; anti-aquaporin-4 antibody; multiple sclerosis