title: The role of anti-aquaporin 4 antibody in the conversion of acute brainstem syndrome to neuromyelitis optica.
abstract: BACKGROUND
  Acute brainstem syndrome (ABS) may herald multiple sclerosis (MS), neuromyelitis optica (NMO), or occur as an isolated syndrome. The aquaporin 4 (AQP4)-specific serum autoantibody, NMO-IgG, is a biomarker for NMO. However, the role of anti-AQP4 antibody in the conversion of ABS to NMO is unclear.
  
  
  METHODS
  Thirty-one patients with first-event ABS were divided into two groups according to the presence of anti-AQP4 antibodies, their clinical features and outcomes were retrospectively analyzed.
  
  
  RESULTS
  Fourteen of 31 patients (45.16 %) were seropositive for NMO-IgG. The 71.43 % of anti-AQP4 (+) ABS patients converted to NMO, while only 11.76 % of anti-AQP4 (-) ABS patients progressed to NMO. Anti-AQP4 (+) ABS patients demonstrated a higher IgG index (0.68 ± 0.43 vs 0.42 ± 0.13, p < 0.01) and Kurtzke Expanded Disability Status Scale (4.64 ± 0.93 vs 2.56 ± 0.81, p < 0.01) than anti-AQP4 (-) ABS patients. Area postrema clinical brainstem symptoms occurred more frequently in anti-AQP4 (+) ABS patients than those in anti-AQP4 (-) ABS patients (71.43 % vs 17.65 %, p = 0.004). In examination of magnetic resonance imaging (MRI), the 78.57 % of anti-AQP4 (+) ABS patients had medulla-predominant involvements in the sagittal view and dorsal-predominant involvements in the axial view.
  
  
  CONCLUSIONS
  ABS represents an inaugural or limited form of NMO in a high proportion of anti-AQP4 (+) patients.
authors: Department of Neurology, The Affiliated Hospital, Hangzhou Normal University, 126 Wenzhou Road, Hangzhou, Zhejiang, 310015, People's Republic of China.
authors: Chen
authors: C
authors: Cheng
authors: Department of Neurology, The Third Affiliated Hospital, Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong, 510630, People's Republic of China. jiangying722@163.com.
authors: Ying
authors: Y
authors: Jiang
authors: Department of Neurology, The Affiliated Hospital, Hangzhou Normal University, 126 Wenzhou Road, Hangzhou, Zhejiang, 310015, People's Republic of China.
authors: Xiaodong
authors: X
authors: Lu
authors: Department of Chemical and Environmental Engineering, University of Nottingham, 199 Taikang East Road, Ningbo, Zhejiang, 315100, People's Republic of China.
authors: Fu
authors: F
authors: Gu
authors: Department of Radiology, the Third Affiliated Hospital, Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong, 510630, People's Republic of China.
authors: Zhuang
authors: Z
authors: Kang
authors: Department of Neurology, The Third Affiliated Hospital, Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong, 510630, People's Republic of China.
authors: Yongqiang
authors: Y
authors: Dai
authors: Department of Neurology, The Third Affiliated Hospital, Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong, 510630, People's Republic of China.
authors: Zhengqi
authors: Z
authors: Lu
authors: Department of Neurology, The Third Affiliated Hospital, Sun Yat-sen University, 600 Tianhe Road, Guangzhou, Guangdong, 510630, People's Republic of China. huxueqiangzssy@163.com.
authors: Xueqiang
authors: X
authors: Hu
mesh_terms: D000208:Acute Disease; D000328:Adult; D051401:Aquaporin 4 / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood*; D020526:Brain Stem Infarctions / Q000000981:diagnostic imaging / Q000276:immunology*; D018450:Disease Progression; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009471:Neuromyelitis Optica / Q000000981:diagnostic imaging / Q000276:immunology*; D012189:Retrospective Studies
chemical_list: C496030:AQP4 protein, human; D051401:Aquaporin 4; D001323:Autoantibodies
keywords: Acute brainstem syndrome; Anti-aquaporin 4 antibody; Magnetic resonance imaging; Neuromyelitis optica