title: Anti-NR2A antibody as a predictor for neuropsychiatric systemic lupus erythematosus.
abstract: OBJECTIVE
  The aim of this study is to establish a detection method for anti-N-methyl-d-aspartate receptor subunit 2A (NR2A) antibody and to evaluate the relationship between anti-NR2A antibody and various organ involvement in SLE.
  
  
  METHODS
  Serum anti-NR2A antibody was measured by ELISA using a peptide with a core of either DWEYS or DWDYS as autoantigen. Additionally, clinical characteristics were compared between 27 anti-NR2A antibody-positive (P group) and 80 antibody-negative (N group) SLE patients using DWDYS peptide.
  
  
  RESULTS
  The optical density (OD) values of anti-NR2A antibody using DWDYS and DWEYS peptides correlated significantly (r = 0.94, P < 0.0001). The median OD value was significantly higher (P < 0.0001) with DWDYS. Additionally, the SLEDAI was significantly higher (P = 0.023) in the P group. The frequency of neuropsychiatric SLE (NPSLE) was significantly higher (P = 0.0002) in the P group, although the frequencies of serositis and nephritis were not statistically significant. Significant correlations were found between anti-NR2A antibody and leucocyte count (r(s) = -0.31, P = 0.001) and haemoglobin (r(s) = -0.42, P < 0.0001), although no correlation was found between anti-NR2A antibody and the titre of anti-dsDNA antibody. NPSLE was the most significant independent variable (P = 0.0008) associated with anti-NR2A antibody positivity, as estimated by multiple linear regression analysis.
  
  
  CONCLUSIONS
  Serum anti-NR2A antibody can be associated with the complication of NPSLE and may indicate the involvement of non-nervous tissue. The use of peptides that include DWDYS is preferable to detect anti-NR2A antibody in ELISA.
authors.affiliation: Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan.
authors.forename: Takahisa
authors.initials: T
authors.lastname: Gono
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Kawaguchi
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Kaneko
authors.forename: Katsuji
authors.initials: K
authors.lastname: Nishimura
authors.forename: Masanori
authors.initials: M
authors.lastname: Hanaoka
authors.forename: Sayuri
authors.initials: S
authors.lastname: Kataoka
authors.forename: Yuko
authors.initials: Y
authors.lastname: Okamoto
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Katsumata
authors.forename: Hisashi
authors.initials: H
authors.lastname: Yamanaka
mesh_terms: D000328:Adult; D000888:Antibodies, Anti-Idiotypic / Q000097:blood*; D000974:Antibodies, Antinuclear / Q000097:blood; D002097:C-Reactive Protein / Q000737:chemistry; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006454:Hemoglobins / Q000737:chemistry; D006801:Humans; D007958:Leukocyte Count; D020945:Lupus Vasculitis, Central Nervous System / Q000097:blood* / Q000276:immunology; D008297:Male; D009393:Nephritis / Q000097:blood; D010455:Peptides; D016194:Receptors, N-Methyl-D-Aspartate / Q000097:blood*; D012189:Retrospective Studies
chemical_list: D000888:Antibodies, Anti-Idiotypic; D000974:Antibodies, Antinuclear; D006454:Hemoglobins; C120997:NR2A NMDA receptor; D010455:Peptides; D016194:Receptors, N-Methyl-D-Aspartate; D002097:C-Reactive Protein