title: Antibodies to beta2-glycoprotein I: a potential marker for clinical features of antiphospholipid antibody syndrome in patients with systemic lupus erythematosus.
abstract: OBJECTIVE
  To clarify risk factors for the development of clinical features of antiphospholipid syndrome (APS) in patients with anticardiolipin antibodies (aCL) in systemic lupus erythematosus (SLE).
  
  
  METHODS
  We studied 65 SLE patients, all with positive IgG and/or IgM aCL. Patients were divided into 2 groups; I: 29 SLE patients with features of APS (SLE/APS) and II: 36 aCL positive SLE patients without any feature of APS (SLE/aCL). Serum samples were collected from our serum bank. Anti-beta2-glycoprotein I (anti-beta2-GPI) were tested by ELISA using irradiated plates in the absence of cardiolipin. Anti-dsDNA antibodies were tested by standard Farr assay.
  
  
  RESULTS
  There were no major differences between SLE clinical manifestations in both groups. However, the frequency of IgG anti-beta2-GPI was markedly increased in SLE/APS (18/29, 62%) than in SLE/aCL (4/36, 11%) (chi-squared 18.6, p=0.0001). The levels of anti-dsDNA antibodies in the same samples were slightly lower in SLE/APS.
  
  
  CONCLUSIONS
  Our data suggest that increased levels of IgG anti-beta2-GPI may be a specific feature of SLE/APS patients rather than reflecting a polyclonal B cell activation.
authors.affiliation: The Rayne Institute and Department of Immunology, St. Thomas' Hospital, London, UK.
authors.forename: S S
authors.initials: SS
authors.lastname: Sanfilippo
authors.forename: M A
authors.initials: MA
authors.lastname: Khamashta
authors.forename: T
authors.initials: T
authors.lastname: Atsumi
authors.forename: O
authors.initials: O
authors.lastname: Amengual
authors.forename: M L
authors.initials: ML
authors.lastname: Bertolaccini
authors.forename: D
authors.initials: D
authors.lastname: D'Cruz
authors.forename: N
authors.initials: N
authors.lastname: Amft
authors.forename: G T
authors.initials: GT
authors.lastname: Swana
authors.forename: G R
authors.initials: GR
authors.lastname: Hughes
mesh_terms: D000328:Adult; D000368:Aged; D000906:Antibodies / Q000032:analysis*; D017153:Antibodies, Anticardiolipin / Q000032:analysis; D000974:Antibodies, Antinuclear / Q000032:analysis; D016736:Antiphospholipid Syndrome / Q000209:etiology / Q000276:immunology*; D015415:Biomarkers; D004247:DNA / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006023:Glycoproteins / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis; D008180:Lupus Erythematosus, Systemic / Q000150:complications / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D053482:beta 2-Glycoprotein I
chemical_list: D000906:Antibodies; D017153:Antibodies, Anticardiolipin; D000974:Antibodies, Antinuclear; D015415:Biomarkers; D006023:Glycoproteins; D007074:Immunoglobulin G; D053482:beta 2-Glycoprotein I; D004247:DNA