title: Presence of anti-Ro/SSA antibody may be associated with anti-aquaporin-4 antibody positivity in neuromyelitis optica spectrum disorder.
abstract: BACKGROUND
  Neuromyelitis optica (NMO) is often associated with systemic autoimmune diseases or serological markers of non-organ-specific autoimmunity, and has been most frequently associated with Sjögren's syndrome and anti-Ro/SSA antibody (SSA-Ab) positivity in Asian populations.
  
  
  OBJECTIVE
  We evaluated the clinical significance of anti-Ro/SSA antibody positivity in patients with NMO spectrum disorder (NMOSD).
  
  
  METHODS
  We retrospectively collected data from 106 consecutive patients with NMOSD and reviewed clinical features and laboratory findings. All patients underwent tests for SSA-Ab and anti-aquaporin-4 antibody (AQP4-Ab) using cell-based indirect immunofluorescence assays.
  
  
  RESULTS
  Among 106 patients, 20 (18.9%) were positive for SSA-Ab. Of 48 AQP4-Ab-positive patients, 18 (37.5%) had SSA-Ab. AQP4-Ab seropositivity was 90.0% in patients positive for SSA-Ab, and 32.6% in patients without SSA-Ab (p<0.001). Presence of SSA-Ab was associated with systemic autoimmune diseases, including Sjögren's syndrome (p<0.001) and systemic lupus erythematosus (p=0.003), and with the presence of non-organ-specific autoantibodies such as anti-nuclear antibody and anti-dsDNA antibody in patients with NMOSD, but was not associated with annualized relapse rate or final Expanded Disability Status Scale score independent of AQP4-Ab positivity.
  
  
  CONCLUSIONS
  We found that the presence of SSA-Ab was highly associated with seropositivity for AQP4-Ab in patients with NMOSD.
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Jae-Hyun
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Jaechun
authors.initials: J
authors.lastname: Hwang
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Ju-Hong
authors.initials: JH
authors.lastname: Min
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Byoung Joon
authors.initials: BJ
authors.lastname: Kim
authors.affiliation: Department of Laboratory Medicine and Genetics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea.
authors.forename: Eun-Suk
authors.initials: ES
authors.lastname: Kang
authors.affiliation: Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea. Electronic address: khlee3590@skku.edu.
authors.forename: Kwang Ho
authors.initials: KH
authors.lastname: Lee
mesh_terms: D000328:Adult; D000974:Antibodies, Antinuclear / Q000097:blood*; D051401:Aquaporin 4 / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood*; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009471:Neuromyelitis Optica / Q000276:immunology*; D012859:Sjogren's Syndrome / Q000276:immunology*
chemical_list: C496030:AQP4 protein, human; D000974:Antibodies, Antinuclear; D051401:Aquaporin 4; D001323:Autoantibodies; C035356:SS-A antibodies
keywords: Anti-Ro/SSA antibody; Anti-aquaporin-4 antibody; Neuromyelitis optica; Neuromyelitis optica spectrum disorder; Non-organ-specific autoantibody; Sjögren's syndrome