title: Antidouble-stranded DNA isotypes in lupus erythematosus patients with prevalent cutaneous presentation.
abstract: BACKGROUND
  Antidouble-stranded DNA antibodies (anti-dsDNA Ab), in particular of the IgG isotype, are usually considered a marker of systemic lupus erythematosus and often correlate with the disease activity.
  
  
  OBJECTIVE
  To determine IgG, IgA and IgM anti-dsDNA Ab in a group of 330 patients with lupus erythematosus and prevalent cutaneous lesions.
  
  
  METHODS
  The titre of anti-dsDNA Ab was determined by enzyme-linked immunosorbent assay, and disease activity was assessed by means of the systemic lupus activity measure.
  
  
  RESULTS
  One hundred and six patients had anti-dsDNA Ab. Thirty-nine patients had antibodies of all three isotypes of immunoglobulins, 17 had IgG + IgM, five IgG + IgA, and two IgA + IgM. Forty-three patients had a single isotype of anti-dsDNA Ab. Patients with systemic disease and higher disease activity had antibodies of all three isotypes of immunoglobulins or of IgG isotype. Remarkably, anti-dsDNA Ab of the IgA isotype, alone or associated with IgM, marked dermatological patients with low disease activity, but often with disquieting clinical and/or laboratory alterations.
  
  
  CONCLUSIONS
  These results indicate a correlation between disease activity and both frequency and isotype of anti-dsDNA Ab.
mesh_terms: D000328:Adult; D000974:Antibodies, Antinuclear / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D004247:DNA / Q000276:immunology*; D005260:Female; D006801:Humans; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008180:Lupus Erythematosus, Systemic / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index
chemical_list: D000974:Antibodies, Antinuclear; D015415:Biomarkers; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D004247:DNA