A cross-reactive idiotype in scleroderma

Clin Exp Immunol. 1997 Jun;108(3):420-7. doi: 10.1046/j.1365-2249.1997.3911292.x.

Abstract

Autoantibodies to centromere proteins (anti-CENPs) and to topoisomerase-I are highly specific for scleroderma. Unlike most autoantibodies in other diseases, these autoantibodies are mutually exclusive. We have analysed the idiotypes (Ids) expressed by anti-CENP-B, antitopoisomerase-I, and IgGs from 20 scleroderma patients. Rabbit anti-Ids were prepared to antitopoisomerase-I from two scleroderma patients, and to anti-CENP-B from four patients. These six anti-Ids were used to study the purified autoantibodies from 20 scleroderma patients: four antitopoisomerase-I, 10 anti-CENP-B, and six purified IgG from scleroderma patients who were negative for both autoantibodies. In addition, we studied sera from 40 normal autoantibody-negative controls, and sera and purified immunoglobulins from 17 systemic lupus erythematosus (SLE) patients containing high titres of anti-double-stranded DNA, and/or autoantibodies to extractable nuclear antigens (ENA). Using direct binding, and competitive inhibition ELISAs and immunoblots, we identified an Id present in the heavy chains of all the affinity-purified antitopoisomerase-I, and anti-CENP-B. Interestingly, this Id was also present in the immunoglobulins of the scleroderma patients who had neither of the two autoantibodies. By contrast, cross-reactive Id-EM was not found in the sera or immunoglobulins from 17 SLE patients, or in the sera from 40 normal subjects. Several samples from two patients showed that this cross-reactive Id-EM was stable over time. The scleroderma disease-specific autoantibodies may be identified through a common structural feature at the variable region of the heavy chain: cross-reactive Id-EM.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Autoantibodies / immunology
  • Autoantigens*
  • Centromere Protein B
  • Chromosomal Proteins, Non-Histone / immunology*
  • Cross Reactions
  • DNA Topoisomerases, Type I / immunology*
  • DNA-Binding Proteins*
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Immunoglobulin Idiotypes / analysis*
  • Longitudinal Studies
  • Rabbits
  • Scleroderma, Systemic / immunology*

Substances

  • Autoantibodies
  • Autoantigens
  • CENPB protein, human
  • Centromere Protein B
  • Chromosomal Proteins, Non-Histone
  • DNA-Binding Proteins
  • Immunoglobulin Idiotypes
  • DNA Topoisomerases, Type I