Vol.23 No.1

Original Article

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

Authors

Yasuhiro Katsumata1 , Yasushi Kawaguchi1 , Sayumi Baba1 , Seisuke Hattori2,3 , Koji Tahara4 , Kaori Ito4 , Tadao Iwasaki4 , Nozomi Yamaguchi4 , Hiroaki Hattori4 , Kinya Nagata4 , Yuko Okamoto1 , Hisashi Yamanaka1,Masako Hara1

  • Institute of Rheumatology, Tokyo Women’s Medical University, 10-22 Kawada-cho, Shinjuku-ku, Tokyo, 162-0054, Japan
  • Division of Cellular Proteomics (BML), Institute of Medical Science, University of Tokyo, Tokyo, Japan
  • Division of Biochemistry, School of Pharmaceutical Science, Kitasato University, Tokyo, Japan
  • Advanced Medical Technology and Development, BML, Saitama, Japan
Received:

5 October 2011

Accepted:

15 February 2012

Published online:

28 March 2012

Full Text

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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.

Key words

Autoantibody - Central nervous system - Systemic lupus erythematosus