Arthritis & Rheumatism, Volume 62,
November 2010 Abstract Supplement
Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Atlanta, Georgia November 6-11, 2010.
Anti-NR2A Antibody as a Predictor for Neuropsychiatric Systemic Lupus Erythematosus.
Hanaoka3, Masanori, Gono3, Takahisa, Kawaguchi1, Yasushi, Kaneko2, Hirotaka, Nishimura2, Katsuji, Katsumata2, Yasuhiro, Okamoto2, Yuko
N-methyl-D-aspartate receptors (NMDAR) are ligand-gated ion channels with crucial roles in synaptic transmission and plasticity of central nervous system (CNS). Additionally, NMDAR are located on non-neuronal tissues, such as bone, skin, pancreas and megakaryocyte. Anti-NMDAR subunit 2A/2B (NR2A/2B) antibody has been reported to react against the peptide DWEYSVWLSN in systemic lupus erythematosus (SLE). Although DWEYS was reported as residues 283287 in NR2A/2B, the actual sequence of residues 283287 is DWDYS in NR2A and DEWDY in NR2B. This will make DWDYS-peptide more specific than DWEYS-peptide in NR2A, even though most reports that have measured anti-NR2 antibody by enzyme-linked immunosorbent assay (ELISA) have used DWEYS-peptide. The aim of the present study is to establish a method to detect serum anti-NR2A antibody by ELISA and to evaluate the relationship between anti-NR2A antibody and various tissue damages in SLE.
Measurement of anti-NR2A antibody in sera was performed by ELISA using either DWEYS- or DWDYS-peptide as autoantigen. Clinical characteristics were compared between anti-NR2A antibody-positive 27 patients (P group) and -negative 80 patients (N group) in SLE, using DWDYS-peptide.
The optical density (OD) value using DWDYS-peptide correlated significantly (r= 0.94, P <0.0001) with the one using DWEYS-peptide in SLE patients. The median OD value was significantly higher (P < 0.0001) in DWDYS-peptide than DWEYS-peptide. The median OD value [interquartile range] using DWDYS-peptide were 0.449 [0.3270.622] and 0.197 [0.140.29] in 107 SLE patients and 74 non-SLE patients, respectively. There was a strikingly significant difference between two subsets (P <0.0001). Additionally, SLE Disease Activity Index (SLEDAI) was significantly higher (P= 0.023) in P group. The frequency of serositis, nephritis and neuropsychiatric SLE (NP SLE) was significantly higher (P= 0.039, 0.015 and 0.0002, respectively) in P group. The frequency of diffuse CNS form and focal CNS form was significantly higher (P= 0.036 and 0.01, and odds ration 3.5 and 5.3, respectively) in P group. The leukocyte count and hemoglobin was significantly decreasing (P= 0.021 and 0.0008, respectively) in P group. Although no correlation were found between anti-NR2A antibody and the titer of anti-DNA antibody, significant correlations were found between anti-NR2A antibody and leukocyte count (r=-0.31, P= 0.001) and hemoglobin (r=-0.42, P < 0.0001). NP SLE was a most significant independent variable (P= 0.0008), associated with anti-NR2A antibody-positivity, estimated by multiple liner regression analysis. The leukocyte count and hemoglobin were also significant variables (P= 0.0095 and 0.013, respectively) associated with anti-NR2A antibody-positivity.
Serum anti-NR2A antibody can be a predictor for NP SLE and may damage also non-nervous tissues. The usage of peptide including DWDYS is more preferable for detecting anti-NR2A antibody in ELISA.
To cite this abstract, please use the following information:
Hanaoka, Masanori, Gono, Takahisa, Kawaguchi, Yasushi, Kaneko, Hirotaka, Nishimura, Katsuji, Katsumata, Yasuhiro, et al; Anti-NR2A Antibody as a Predictor for Neuropsychiatric Systemic Lupus Erythematosus. [abstract]. Arthritis Rheum 2010;62 Suppl 10 :1844