title: Autoantibodies to C-reactive protein in incomplete lupus and systemic lupus erythematosus.
abstract: OBJECTIVE
  Anti-C-reactive protein (CRP) antibodies have been described in patients with systemic lupus erythematosus (SLE). We investigated the potential of the anti-CRP antibody as a marker for disease activity in SLE patients and as a predictor of progression to SLE in patients with incomplete lupus.
  
  
  METHODS
  Immunoglobulin G anti-CRP antibody levels were measured using an enzyme-linked immunosorbent assay.
  
  
  RESULTS
  Patients with incomplete lupus exhibited clinical and immunologic characteristics different from those in SLE patients: no serositis and alopecia, more common oral ulcers and arthritis, lower disease activity index, lower positivity for antinuclear and anti-double-strand DNA antibodies, and higher complement levels. Anti-CRP antibody levels were higher in SLE patients (35.6 [35.1] AU) than in patients with incomplete lupus (23.1 [25.8] AU, P = 0.016) and normal controls (21.0 [14.3] AU, P < 0.001). Anti-CRP antibody was significantly higher in SLE patients with arthritis and correlated with disease activity markers, including antichromatin antibody. However, no difference in anti-CRP antibody levels was observed between patients with incomplete lupus that progressed to SLE and those whose did not.
  
  
  CONCLUSIONS
  These data suggest that anti-CRP antibodies can neither be used as biomarkers in SLE nor predict SLE progression in patients with incomplete lupus.
authors.affiliation: From the Department of Rheumatology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Ju-Yang
authors.initials: JY
authors.lastname: Jung
authors.forename: Bo-Ram
authors.initials: BR
authors.lastname: Koh
authors.forename: Hyoun-Ah
authors.initials: HA
authors.lastname: Kim
authors.forename: Ja-Young
authors.initials: JY
authors.lastname: Jeon
authors.forename: Chang-Hee
authors.initials: CH
authors.lastname: Suh
mesh_terms: D000328:Adult; D001323:Autoantibodies / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D008180:Lupus Erythematosus, Systemic / Q000097:blood* / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D015415:Biomarkers; D007074:Immunoglobulin G; D002097:C-Reactive Protein