title: Longitudinally extensive transverse myelitis with and without aquaporin 4 antibodies.
abstract: OBJECTIVE
  Aquaporin 4 antibody (AQP4-Ab)-negative patients with longitudinally extensive transverse myelitis (LETM) behave differently from those with AQP4-Ab. Aquaporin 4 antibody-negative neuromyelitis optica (NMO) is rare when good assays are used.
  
  
  OBJECTIVE
  To assess if AQP4-Ab-negative patients with LETM share similar disease characteristics with AQP4-Ab-positive patients or whether they have distinct features and alternative diagnoses. DESIGN We collated clinical and paraclinical data on patients with LETM identified through the Oxford NMO clinical database. Aquaporin 4 antibodies were tested using 2 sensitive assays. We describe the features of patients with LETM, compare findings between patients with and without AQP4-Ab, and describe alternative diagnoses in AQP4-Ab-negative patients.
  
  
  METHODS
  Single specialist UK center for NMO.
  
  
  METHODS
  Seventy-six adult patients with LETM.
  
  
  METHODS
  Comparison of clinical and paraclinical data.
  
  
  RESULTS
  Fifty-eight percent of patients were AQP4-Ab positive. Alternative diagnoses could usually be identified in AQP4-Ab-negative patients, including those fulfilling NMO diagnostic criteria. Only 6.5% of patients had "true" seronegative NMO and 6.5% had idiopathic LETM. There were some important differences between AQP4-Ab-positive and -negative cases, including older onset age, higher proportion of females, lower incidence of simultaneous optic neuritis, lower frequency of conus involvement, and higher prevalence of coexisting autoimmune disorders in AQP4-Ab-positive cases. Attack severity and degree of recovery were similar in the 2 groups.
  
  
  CONCLUSIONS
  Patients with LETM without AQP4-Ab include a number of different diagnostic categories and it is not surprising therefore that they show important differences compared with AQP4-Ab-positive patients, even when considering only those fulfilling current NMO diagnostic criteria. Thus, we suggest that diagnoses such as myelin-oligodendrocyte glycoprotein antibody disease, multiple sclerosis, acute disseminated encephalomyelitis, and postinfectious disorders should be exclusions in the NMO diagnostic criteria and AQP4-Ab-positive and antibody-negative NMO/NMO spectrum disorder cohorts should be analyzed separately.
authors.affiliation: Nuffield Department of Clinical Neurosciences, Oxford University Hospitals NHS Trust, University of Oxford, Oxford, England.
authors.forename: Joanna
authors.initials: J
authors.lastname: Kitley
authors.forename: Maria Isabel
authors.initials: MI
authors.lastname: Leite
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Küker
authors.forename: Gerardine
authors.initials: G
authors.lastname: Quaghebeur
authors.forename: Jithin
authors.initials: J
authors.lastname: George
authors.forename: Patrick
authors.initials: P
authors.lastname: Waters
authors.forename: Mark
authors.initials: M
authors.lastname: Woodhall
authors.forename: Angela
authors.initials: A
authors.lastname: Vincent
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Palace
mesh_terms: D000328:Adult; D000368:Aged; D051401:Aquaporin 4 / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood*; D005260:Female; D057809:HEK293 Cells; D006801:Humans; D053208:Kaplan-Meier Estimate; D008137:Longitudinal Studies; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009188:Myelitis, Transverse / Q000097:blood* / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D009471:Neuromyelitis Optica / Q000097:blood* / Q000150:complications / Q000175:diagnosis; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D014162:Transfection
chemical_list: D051401:Aquaporin 4; D001323:Autoantibodies