title: Distinct features between longitudinally extensive transverse myelitis presenting with and without anti-aquaporin 4 antibodies.
abstract: OBJECTIVE
  Longitudinally extensive transverse myelitis (LETM) with spinal cord lesions spanning three or more vertebral segments is a key feature of neuromyelitis optica (NMO). However, the role of anti-aquaporin 4 (anti-AQP4) antibody, a sensitive biomarker of NMO, in the conversion of LETM to NMO remains uncertain.
  
  
  METHODS
  Thirty first-ever LETM patients were retrospectively analysed and divided into two groups according to the presence of anti-AQP4 antibodies.
  
  
  RESULTS
  Eighteen (60%) patients presented with anti-AQP4 antibodies. Fifteen (83.33%) anti-AQP4 (+) LETM patients converted to NMO, while only three of 12 (25%, p = 0.002) anti-AQP4 (-) LETM patients progressed to NMO, over a mean follow-up period of 5.63 years. Seven (38.89%) anti-AQP4 (+) and one (8.33%) anti-AQP4 (-) LETM patients received interferon-β1a treatment, respectively. Anti-AQP4 (+) LETM patients demonstrated a higher immunogamma globulin (IgG) index (0.68 ± 0.43 versus 0.47 ± 0.19, p = 0.018), annual relapse rate (0.72 ± 0.31 versus 0.42 ± 0.17, p = 0.01) and Kurtzke Expanded Disability Status Scale (4.28 ± 2.22 versus 2.67 ± 2.26, p = 0.031), than anti-AQP4 (-) LETM patients. In spinal magnetic resonance imaging (MRIs), more than half (58.33%) of the anti-AQP4 (+) LETM patients were observed to have central grey matter-predominant involvement in the axial view, while peripheral white matter-predominant involvement (51.85%) was the most common pattern observed in the anti-AQP4 (-) LETM patients.
  
  
  CONCLUSIONS
  Anti-AQP4 (+) LETM demonstrated a high conversion rate to NMO (83.33%), suggesting that anti-AQP4 (+) LETM may represent an early, isolated syndrome of NMO spectrum disorder. The greater number of patients receiving interferon-β treatment in anti-AQP4 (+) LETM may contribute to its high annual relapse rate.
authors: Section of Neuromuscular Diseases, Department of Neurology, Chang Gung Memorial Hospital, Linkou Medical Center and University College of Medicine, Taiwan.
authors: K-H
authors: KH
authors: Chang
authors: R-K
authors: RK
authors: Lyu
authors: C-M
authors: CM
authors: Chen
authors: Y-R
authors: YR
authors: Wu
authors: H-S
authors: HS
authors: Chang
authors: C-C
authors: CC
authors: Huang
authors: H-C
authors: HC
authors: Kuo
authors: C-C
authors: CC
authors: Chu
authors: W-C
authors: WC
authors: Hsu
authors: L-S
authors: LS
authors: Ro
mesh_terms: D000328:Adult; D051401:Aquaporin 4 / Q000276:immunology*; D001323:Autoantibodies / Q000096:biosynthesis*; D003937:Diagnosis, Differential; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009188:Myelitis, Transverse / Q000175:diagnosis* / Q000276:immunology* / Q000473:pathology; D009471:Neuromyelitis Optica / Q000175:diagnosis* / Q000276:immunology* / Q000473:pathology; D012189:Retrospective Studies
chemical_list: D051401:Aquaporin 4; D001323:Autoantibodies