title: The prevalence, onset, and clinical significance of antiphospholipid antibodies prior to diagnosis of systemic lupus erythematosus.
abstract: OBJECTIVE
  To determine whether antiphospholipid antibodies (aPL) occur before the diagnosis of systemic lupus erythematosus (SLE) and before initial clotting events, and whether their presence early in the disease course influences clinical outcome.
  
  
  METHODS
  Serum samples obtained from 130 lupus patients before and after SLE diagnosis were screened for IgG and IgM aPL using an anticardiolipin (aCL) enzyme-linked immunosorbent assay. Medical records of all patients were carefully reviewed for data on the time of onset of SLE features meeting clinical criteria and on disease manifestations.
  
  
  RESULTS
  Twenty-four patients (18.5%) were positive for IgG and/or IgM aCL prior to SLE diagnosis. Anticardiolipin antibodies appeared from 7.6 years prior to SLE diagnosis to within the same month as SLE diagnosis, with a mean onset occurring 3.0 years before SLE diagnosis. Additionally, aCL presence early in the disease process seemed to predict a more severe clinical outcome; these patients eventually met an average of 6.1 of the 11 classification criteria for SLE, compared with 4.9 criteria for other patients (P < 0.001). The early aCL-positive population also had more frequent renal disease, central nervous system disease, thrombocytopenia, and clotting events. In this population, aCL preceded initial thrombotic events by a mean of 3.1 years.
  
  
  CONCLUSIONS
  Anticardiolipin antibodies in SLE patients tend to precede initial clotting events by several years. Furthermore, the presence of early, prediagnosis aPL seems to herald a more varied, severe clinical course with earlier onset in patients with SLE.
authors.affiliation: Oklahoma Medical Research Foundation and University of Oklahoma Health Sciences Center, Oklahoma City 73104, USA.
authors.forename: Micah T
authors.initials: MT
authors.lastname: McClain
authors.forename: Melissa R
authors.initials: MR
authors.lastname: Arbuckle
authors.forename: Latisha D
authors.initials: LD
authors.lastname: Heinlen
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Dennis
authors.forename: Jon
authors.initials: J
authors.lastname: Roebuck
authors.forename: Mark V
authors.initials: MV
authors.lastname: Rubertone
authors.forename: John B
authors.initials: JB
authors.lastname: Harley
authors.forename: Judith A
authors.initials: JA
authors.lastname: James
mesh_terms: D000293:Adolescent; D000328:Adult; D001741:Black or African American; D017668:Age of Onset; D017153:Antibodies, Anticardiolipin / Q000097:blood*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008180:Lupus Erythematosus, Systemic / Q000175:diagnosis / Q000453:epidemiology* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D012720:Severity of Illness Index; D017678:Sex Distribution; D013927:Thrombosis / Q000453:epidemiology; D044465:White People
chemical_list: D017153:Antibodies, Anticardiolipin; D007074:Immunoglobulin G; D007075:Immunoglobulin M