title: Neuromyelitis optica antibodies in patients with severe optic neuritis in China.
abstract: BACKGROUND
  Severe visual loss is seen in both multiple sclerosis-associated optic neuritis (ON) and neuromyelitis optica (NMO)-associated ON. NMO (aquaporin 4) antibodies have been reported to have diagnostic and prognostic value for visual and neurological outcomes of recurrent ON. We performed this study to investigate the frequency of NMO antibodies and its prognostic value for visual and neurological outcomes in Chinese patients with severe ON.
  
  
  METHODS
  Single-center prospective cohort study. Detection of NMO antibodies was by indirect immunofluorescence method using human aquaporin 4-transfected cells. Severe ON was defined as visual acuity of 20/200 or worse in at least 1 eye at the nadir of the patients' course. Clinical features at baseline, visual outcome, and sequential neurological events were compared between seropositive and seronegative groups.
  
  
  RESULTS
  NMO antibodies were detected in 11 of 34 patients (32.4%) with severe ON. Five seropositive patients with recurrent ON had significantly higher titers (range: 1:512 to 1:65,536; median: 1:512) than those of 6 seropositive patients with only 1 episode (range: 1:16 to 1:512; median: 1:32) (P=0.021). Female to male ratio (10:1) and antinuclear autoantibody positivity in seropositive patients (3 of 9, 33.3%) were statistically higher than those of the seronegative group (12:11; 0 of 19; P=0.026). The seropositive patients had significantly poorer visual outcomes than seronegative patients (P=0.025). During the averaged 32-month follow-up, 2 of 11 seropositive patients (18.2%) developed clinically incomplete transverse myelitis, while no similar symptoms were reported in the seronegative group.
  
  
  CONCLUSIONS
  NMO antibody positivity is relatively high in Chinese patients with severe ON and suggests a poorer visual outcome, probably higher risk of developing spinal cord lesions and a closer association with systemic autoimmune disorders.
authors.affiliation: Department of Neurology, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Chuntao
authors.initials: C
authors.lastname: Lai
authors.forename: Guohong
authors.initials: G
authors.lastname: Tian
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Takahashi
authors.forename: Wu
authors.initials: W
authors.lastname: Liu
authors.forename: Ling
authors.initials: L
authors.lastname: Yang
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Zhang
mesh_terms: D000293:Adolescent; D000328:Adult; D051401:Aquaporin 4 / Q000276:immunology*; D001323:Autoantibodies / Q000096:biosynthesis / Q000097:blood*; D002681:China / Q000453:epidemiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009471:Neuromyelitis Optica / Q000097:blood / Q000175:diagnosis / Q000276:immunology*; D009902:Optic Neuritis / Q000097:blood / Q000175:diagnosis / Q000276:immunology*; D011446:Prospective Studies; D012720:Severity of Illness Index; D055815:Young Adult
chemical_list: C496030:AQP4 protein, human; D051401:Aquaporin 4; D001323:Autoantibodies