title: Aquaporin 4 antibodies in the cerebrospinal fluid are helpful in diagnosing Chinese patients with neuromyelitis optica.
abstract: OBJECTIVE
  It was the aim of this study to compare the diagnostic efficiency of anti-aquaporin 4 (AQP4) antibody detection between serum and cerebrospinal fluid (CSF) samples in Chinese patients with central nervous system demyelinating diseases.
  
  
  METHODS
  Anti-AQP4 antibodies were detected by a cell-based assay. We calculated the sensitivity, specificity and coherence in 118 patients with neuromyelitis optica (NMO, n = 39), multiple sclerosis (n = 34), longitudinally extensive transverse myelitis (LETM, n = 22), optic neuritis (ON, n = 6), opticospinal multiple sclerosis (n = 8) and acute partial transverse myelitis (n = 9).
  
  
  RESULTS
  Forty-four serum samples (33.8%) were positive for anti-AQP4 antibodies. Anti-AQP4 antibody seropositivity was 76.9, 59.1 and 16.7% in patients with NMO, LETM and ON, respectively. Sixty-five CSF samples (50%) were positive for anti-AQP4 antibodies. Anti-AQP4 antibody positivity was 87.1, 81.8, 83.3, 62.5 and 11.8% in patients with NMO, LETM, ON, opticospinal multiple sclerosis and multiple sclerosis, respectively. The κ value of the coherence test was 0.585 (p < 0.0001) between the two types of samples. The antibody positivity rate was significantly different between the two body fluids (p = 0.0008, McNemar test). The sensitivity and specificity were 74.3 and 100% in serum, 85.7 and 88.2% in CSF, and 94.3 and 88.2% for serum and CSF combined, respectively.
  
  
  CONCLUSIONS
  The sensitivity of anti-AQP4 antibodies in the CSF was higher than that in the serum, and their combined use is helpful in diagnosing Chinese patients with NMO.
authors.affiliation: Department of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, PR China.
authors.forename: Youming
authors.initials: Y
authors.lastname: Long
authors.forename: Wei
authors.initials: W
authors.lastname: Qiu
authors.forename: Zhengqi
authors.initials: Z
authors.lastname: Lu
authors.forename: Jian
authors.initials: J
authors.lastname: Bao
authors.forename: Aimin
authors.initials: A
authors.lastname: Wu
authors.forename: Yuge
authors.initials: Y
authors.lastname: Wang
authors.forename: Honghao
authors.initials: H
authors.lastname: Wang
authors.forename: Xueqiang
authors.initials: X
authors.lastname: Hu
mesh_terms: D000293:Adolescent; D000328:Adult; D051401:Aquaporin 4 / Q000097:blood / Q000134:cerebrospinal fluid / Q000276:immunology*; D044466:Asian People; D001323:Autoantibodies / Q000096:biosynthesis / Q000097:blood / Q000134:cerebrospinal fluid*; D015415:Biomarkers / Q000097:blood / Q000134:cerebrospinal fluid; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009471:Neuromyelitis Optica / Q000097:blood / Q000134:cerebrospinal fluid* / Q000175:diagnosis*; D055815:Young Adult
chemical_list: D051401:Aquaporin 4; D001323:Autoantibodies; D015415:Biomarkers