title: Evaluation of clinical interest of anti-aquaporin-4 autoantibody followup in neuromyelitis optica.
abstract: Neuromyelitis optica (NMO) is an autoimmune disease in which a specific biomarker named NMO-IgG and directed against aquaporin-4 (AQP4) has been found. A correlation between disease activity and anti-AQP4 antibody (Ab) serum concentration or complement-mediated cytotoxicity has been reported, but the usefulness of longitudinal evaluation of these parameters remains to be evaluated in actual clinical practice. Thirty serum samples from 10 NMO patients positive for NMO-IgG were collected from 2006 to 2011. Anti-AQP4 Ab serum concentration and complement-mediated cytotoxicity were measured by flow cytometry using two quantitative cell-based assays (CBA) and compared with clinical parameters. We found a strong correlation between serum anti-AQP4 Ab concentration and complement-mediated cytotoxicity (P < 0.0001). Nevertheless, neither relapse nor worsening of impairment level was closely associated with a significant increase in serum Ab concentration or cytotoxicity. These results suggest that complement-mediated serum cytotoxicity assessment does not provide extra insight compared to anti-AQP4 Ab serum concentration. Furthermore, none of these parameters appears closely related to disease activity and/or severity. Therefore, in clinical practice, serum anti-AQP4 reactivity seems not helpful as a predictive biomarker in the followup of NMO patients as a means of predicting the onset of a relapse and adapting the treatment accordingly.
authors.affiliation: Département de Neurologie, Hôpitaux Universitaires de Strasbourg, 1 Avenue Molière, 67091 Strasbourg, France.
authors.forename: Jean-Baptiste
authors.initials: JB
authors.lastname: Chanson
authors.forename: Melissa
authors.initials: M
authors.lastname: Alame
authors.forename: Nicolas
authors.initials: N
authors.lastname: Collongues
authors.forename: Frédéric
authors.initials: F
authors.lastname: Blanc
authors.forename: Marie
authors.initials: M
authors.lastname: Fleury
authors.forename: Gabrielle
authors.initials: G
authors.lastname: Rudolf
authors.forename: Jérôme
authors.initials: J
authors.lastname: de Seze
authors.forename: Thierry
authors.initials: T
authors.lastname: Vincent
mesh_terms: D000328:Adult; D051401:Aquaporin 4 / Q000097:blood / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D015415:Biomarkers / Q000097:blood; D003165:Complement System Proteins / Q000276:immunology*; D003602:Cytotoxicity, Immunologic; D005500:Follow-Up Studies; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology*; D008875:Middle Aged; D009471:Neuromyelitis Optica / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D011237:Predictive Value of Tests; D012008:Recurrence; D012720:Severity of Illness Index
chemical_list: D051401:Aquaporin 4; D001323:Autoantibodies; D015415:Biomarkers; D007074:Immunoglobulin G; D003165:Complement System Proteins