title: Diagnostic performance and clinical associations of antibodies to the chromatin antigenic system in juvenile systemic lupus erythematosus.
abstract: OBJECTIVE
  To determine the frequency of antibodies to chromatin components in juvenile systemic lupus erythematosus (JSLE), and to correlate the presence of these autoantibodies with clinical manifestations and disease activity.
  
  
  METHODS
  Anti-chromatin (anti-CHR), anti-nucleosome core particle (anti-NCS) and anti-dsDNA antibodies were measured in 175 individuals, including 37 patients with active JSLE and 41 with inactive disease, 47 non-lupus autoimmune disease patients (non-lupus AD), and 50 healthy children. An in-house ELISA was developed with purified nucleosome core particles from calf thymus to determine IgG and IgG3 anti-NCS antibodies. Anti-CHR and anti-dsDNA antibodies were detected by commercial ELISA kits (INOVA).
  
  
  RESULTS
  Anti-NCS and anti-CHR antibodies exhibited high specificity for JSLE and similar frequency in active and inactive JSLE. Anti-CHR and IgG/IgG3 anti-NCS serum levels did not differ between active and inactive JSLE. SLEDAI correlated with anti-dsDNA antibodies but not with antibodies to other chromatin components. There was association of anti-dsDNA, anti-CHR and IgG/IgG3 anti-NCS antibodies with proteinuria and low C4 serum levels. Anti-NCS antibodies in the absence of anti-dsDNA were observed in 14% of the JSLE patients.
  
  
  CONCLUSIONS
  Our data indicate that anti-NCS and anti-CHR antibodies are relevant diagnostic markers for JSLE and appear to be correlated with JSLE lupus nephritis activity. IgG3 isotype anti-NCS antibodies do not seem to be more relevant than IgG anti-NCS antibodies as markers of disease activity or active nephritis in JSLE.
authors.affiliation: Universidade Federal de São Paulo.
authors.forename: Silene Peres
authors.initials: SP
authors.lastname: Keusseyan
authors.forename: Neusa Pereira
authors.initials: NP
authors.lastname: da Silva
authors.forename: Maria Odete Esteves
authors.initials: MO
authors.lastname: Hilário
authors.forename: Eunice Mitiko
authors.initials: EM
authors.lastname: Okuda
authors.forename: Maria Teresa S L R Ascenção
authors.initials: MT
authors.lastname: Terreri
authors.forename: Luis Eduardo Coelho
authors.initials: LE
authors.lastname: Andrade
mesh_terms: D000293:Adolescent; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology*; D001324:Autoantigens / Q000097:blood* / Q000276:immunology*; D002648:Child; D002843:Chromatin / Q000276:immunology*; D005260:Female; D006801:Humans; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000175:diagnosis* / Q000276:immunology; D008297:Male
chemical_list: D001323:Autoantibodies; D001324:Autoantigens; D002843:Chromatin