title: False positivity of anti aquaporin-4 antibodies in natalizumab-treated patients.
abstract: Neuromyelitis optica spectrum disorders (NMOSD) represent a differential diagnosis of multiple sclerosis (MS). Detection of anti-aquaporin-4 antibodies (AQP4-Ab) is the strongest argument to confirm NMOSD. Diagnosing NMOSD is a major concern because specific MS disease modifying drugs can lead to neurological worsening.
  
  
  
  To report the case of two natalizumab (NTZ) treated patients who presented a false positive result for AQP4-Ab.
  
  
  
  A retrospective analysis of NTZ-treated patients who were tested positive for AQP4-Ab in our MS center.
  
  
  
  Two patients treated by NTZ presented a false positive result.
  
  
  
  Clinicians should be aware of potential technical issues in detecting AQP4-Ab in NTZ-treated patients leading to false positive results.
authors: Department of Neurology, Hopital Pasteur, CHU de Nice, Nice, France cohen.m@chu-nice.fr.
authors: Mikael
authors: M
authors: Cohen
authors: Department of Neurology, CHU de Strasbourg, Strasbourg, France.
authors: Jérome
authors: J
authors: De Sèze
authors: Department of Neurology, CHU de Lyon, Lyon, France.
authors: Romain
authors: R
authors: Marignier
authors: Department of Neurology, Hopital Pasteur, CHU de Nice, Nice, France.
authors: Christine
authors: C
authors: Lebrun
mesh_terms: D000328:Adult; D051401:Aquaporin 4 / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood*; D015551:Autoimmunity; D015415:Biomarkers / Q000097:blood; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects / Q000627:therapeutic use*; D008297:Male; D009103:Multiple Sclerosis / Q000097:blood / Q000175:diagnosis / Q000188:drug therapy* / Q000276:immunology; D000069442:Natalizumab / Q000009:adverse effects / Q000627:therapeutic use*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012698:Serologic Tests; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: C496030:AQP4 protein, human; D051401:Aquaporin 4; D001323:Autoantibodies; D015415:Biomarkers; D007166:Immunosuppressive Agents; D000069442:Natalizumab
keywords: Multiple sclerosis; natalizumab; neuromyelitis optica