Serum antibodies against the 70k polypeptides of the U1 ribonucleoprotein complex are associated with psychiatric syndromes in systemic lupus erythematosus: a retrospective study

• Published in: Modern rheumatology 2013-01, Vol.23 (1), p.71-80
• Main Authors: Katsumata, Yasuhiro, Kawaguchi, Yasushi, Baba, Sayumi, Hattori, Seisuke, Tahara, Koji, Ito, Kaori, Iwasaki, Tadao, Yamaguchi, Nozomi, Hattori, Hiroaki, Nagata, Kinya, Okamoto, Yuko, Yamanaka, Hisashi, Hara, Masako
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Antibodies, Antinuclear - blood; Autoantibody; Central nervous system; Female; Humans; Lupus; Lupus Vasculitis, Central Nervous System - blood; Lupus Vasculitis, Central Nervous System - complications; Male; Middle Aged; Molecular Weight; Neurochemistry; Neurology; Peptides - immunology; Polyclonal antibodies; Polypeptides; Proteins; Psychopathology; Psychotic Disorders - blood; Psychotic Disorders - etiology; Recombinant Proteins; Retrospective Studies; Ribonucleoprotein, U1 Small Nuclear - immunology; Syndrome; Systemic lupus erythematosus; Young Adult
• ISSN: 1439-7595; 1439-7609
• DOI: 10.3109/s10165-012-0624-y

Abstract Objectives: We assessed the association between serum autoantibodies against the 70-kDa polypeptide of the U1-ribonucleoprotein (RNP) complex (U1-70k) and the central nervous system (CNS) syndromes in systemic lupus erythematosus (SLE) patients. Methods: We studied 106 hospitalized patients with active SLE, comparing those with (n = 32) and without (n = 74) CNS syndromes. CNS syndromes were further classified into neurologic (n = 21) and psychiatric (n = 15) disorders. Immunoglobulin G (IgG) anti-U1-70k antibodies were measured by enzyme-linked immunosorbent assay (ELISA) using recombinant antigens. IgG antibodies against whole U1-RNP were measured using commercial ELISA kits. Results: Although there was no significant difference in the levels of serum anti-U1-70k antibodies in SLE patients with or without CNS syndromes (p = 0.83), the levels were significantly elevated in SLE patients compared with patients without psychiatric syndromes (p = 0.030). In contrast, no significant difference was observed in the levels of serum anti-U1-RNP antibodies in SLE patients with or without psychiatric syndromes (p = 0.555). Conclusions: These results indicate that serum anti-U1-70k antibodies are associated with psychiatric syndromes in SLE but that they are not associated with CNS syndromes as a whole or with neurologic syndromes. The anti-U1-70k antibodies might be involved in the pathological mechanisms of psychiatric syndromes in SLE.