title: Idiopathic aquaporin-4 antibody negative longitudinally extensive transverse myelitis.
abstract: BACKGROUND
  Longitudinally extensive transverse myelitis (LETM) is a characteristic manifestation of neuromyelitis optica (NMO). However, not all patients with LETM are positive for aquaporin-4 (AQP4) antibodies. We evaluated the characteristics of idiopathic isolated LETM negative for AQP4 antibodies.
  
  
  METHODS
  From the National Cancer Center registry of inflammatory diseases of the central nervous system, patients with LETM as an initial manifestation and follow-up for at least two years were enrolled. Their medical records and MRIs were reviewed retrospectively. AQP4 antibody was confirmed by three different validated methods at least three times. Cerebrospinal fluid (CSF) glial fibrillary acidic protein (GFAP) levels were measured to investigate astrocyte damage.
  
  
  RESULTS
  Among 108 patients with first-ever LETM, 55 were positive for AQP4 antibodies (P-LETM) and 53 were consistently negative. Of them, seven were later diagnosed with seronegative NMO, and four were positive for MOG antibodies. The remaining 42 patients (N-LETM) showed several features distinct from P-LETM: male predominance, older age of onset, milder clinical presentation, spinal cord confinement and absence of combined autoimmunity. CSF GFAP levels were not increased in N-LETM but were markedly elevated in P-LETM.
  
  
  CONCLUSIONS
  Idiopathic isolated N-LETM is not that rare among first-ever LETM, and has many features distinct from P-LETM where astrocytic damage is evident.
authors.affiliation: Department of Neurology, Research Institute and Hospital of National Cancer Center, Goyang, Korea.
authors.forename: Jae-Won
authors.initials: JW
authors.lastname: Hyun
authors.affiliation: Department of Neurology, Research Institute and Hospital of National Cancer Center, Goyang, Korea.
authors.forename: Su-Hyun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Kosin University School of Medicine, Busan, Korea.
authors.forename: So-Young
authors.initials: SY
authors.lastname: Huh
authors.affiliation: Catholic University School of Medicine, Seoul, Korea.
authors.forename: Woojun
authors.initials: W
authors.lastname: Kim
authors.affiliation: Department of Neurology, Research Institute and Hospital of National Cancer Center, Goyang, Korea.
authors.forename: Junglim
authors.initials: J
authors.lastname: Yun
authors.affiliation: Department of Neurology, Research Institute and Hospital of National Cancer Center, Goyang, Korea.
authors.forename: AeRan
authors.initials: A
authors.lastname: Joung
authors.affiliation: Department of Neurology and Multiple Sclerosis Therapeutics, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Douglas Kazutoshi
authors.initials: DK
authors.lastname: Sato
authors.affiliation: Department of Neurology and Multiple Sclerosis Therapeutics, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Fujihara
authors.affiliation: Department of Neurology, Research Institute and Hospital of National Cancer Center, Goyang, Korea hojinkim@ncc.re.kr.
authors.forename: Ho Jin
authors.initials: HJ
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D051401:Aquaporin 4 / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000134:cerebrospinal fluid; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D063308:Myelin-Oligodendrocyte Glycoprotein / Q000276:immunology; D009188:Myelitis, Transverse / Q000097:blood* / Q000134:cerebrospinal fluid / Q000145:classification / Q000503:physiopathology*; D012042:Registries; D012737:Sex Factors; D055815:Young Adult
chemical_list: C496030:AQP4 protein, human; D051401:Aquaporin 4; D001323:Autoantibodies; D005904:Glial Fibrillary Acidic Protein; D063308:Myelin-Oligodendrocyte Glycoprotein
keywords: Longitudinally extensive transverse myelitis; aquaporin-4 antibody; idiopathic; neuromyelitis optica