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

Tokyo Women's Medical Univ, Tokyo, Japan
Tokyo Women's Medical Univ
Tokyo Women's Medical University
Tokyo Womens Med Univ, Shinjuku-ku, Tokyo, Japan

Purpose:

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 283–287 in NR2A/2B, the actual sequence of residues 283–287 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.

Methods:

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.

Results:

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 [0.327–0.622] and 0.197 [0.14–0.29] 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.

Conclusion:

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
DOI: 10.1002/art.29609

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