Association between anti-U1 ribonucleoprotein antibodies and inflammatory mediators in cerebrospinal fluid of patients with neuropsychiatric systemic lupus erythematosus.
OBJECTIVE
We investigated possible associations between neurotoxic inflammatory mediators (IMs) and anti-U1RNP antibodies (Abs) in cerebrospinal fluid (CSF) of neuropsychiatric systemic lupus erythematosus (NPSLE).


METHODS
Serum and CSF anti-U1RNP Abs were detected using an RNA-immunoprecipitation assay and CSF anti-U1RNP Ab levels were measured by ELISA. IFN-α, MCP-1 and IL-8 levels in CSF were determined by quantitative multiplex cytokine analysis. IM levels were compared among anti-U1RNP-positive and anti-U1RNP-negative NPSLE as well as other rheumatic disease controls (controls).


RESULTS
Anti-U1RNP Abs were detected in serum (58%) and in CSF (18%) of 82 NPSLE patients. CSF MCP-1 levels were higher in NPSLE than in controls. CSF IFN-α level was higher in CSF anti-U1RNP Ab-positive than in -negative patients or controls. When limited to serum anti-U1RNP Ab-positive patients, however, levels of all three IMs in CSF were higher in CSF anti-U1RNP Ab-positive than in -negative patients. Anti-U1RNP Ab levels in CSF correlated with CSF MCP-1, but not IFN-α and IL-8 levels.


CONCLUSIONS
CSF anti-U1RNP Ab positivity is associated with increased level of CSF IFN-α. MCP-1 levels correlated with CSF anti-U1RNP Ab levels, whereas the increased CSF MCP-1 was not specific to CSF anti-U1RNP Ab-positive NPSLE.
Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Japan.
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Yokoyama
Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Japan Department of the Control for Rheumatic Diseases, Graduate School of Medicine, Kyoto University, Japan takfujii@kuhp.kyoto-u.ac.jp.
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Fujii
Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Japan.
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Kondo-Ishikawa
Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Japan.
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Yamakawa
Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Japan.
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Nakano
Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Japan.
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Yukawa
Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Japan.
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Yoshifuji
Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Japan.
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Ohmura
Department of Rheumatology and Clinical Immunology, Graduate School of Medicine, Kyoto University, Japan Department of the Control for Rheumatic Diseases, Graduate School of Medicine, Kyoto University, Japan.
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Mimori
D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000097:blood* / Q000134:cerebrospinal fluid*; D002648:Child; D005260:Female; D006801:Humans; D007249:Inflammation / Q000097:blood / Q000134:cerebrospinal fluid; D020945:Lupus Vasculitis, Central Nervous System / Q000097:blood* / Q000134:cerebrospinal fluid* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D017412:Ribonucleoprotein, U1 Small Nuclear / Q000097:blood* / Q000134:cerebrospinal fluid*; D055815:Young Adult
D001323:Autoantibodies; D017412:Ribonucleoprotein, U1 Small Nuclear
Anti-U1RNP antibodies; IFN-α; MCP-1; cerebrospinal fluid; neuropsychiatric systemic lupus erythematosus