title: Antiphosphatidylethanolamine antibodies as the only antiphospholipid antibodies detected by ELISA. II. Kininogen reactivity.
abstract: OBJECTIVE
  To study the requirement for serum and for low (LMWK) and high molecular weight kininogen (HMWK) and/or HMWK binding proteins to detect antiphosphatidylethanolamine antibodies (aPE) in ELISA.
  
  
  METHODS
  Eighteen patients with aPE (9 IgG and 13 IgM) as the only antiphospholipid antibody (aPL) detected by ELISA were assigned to 4 groups: thromboembolic episodes (TEE) (Group I, n = 6); livedo reticularis (LR) without TEE, (Group II, n = 4); both LR and thrombosis (Group III, n = 4); and systemic lupus erythematosus (SLE) or primary antiphospholipid syndrome (APS) (Group IV, n = 4). All sera were analyzed in ELISA with and without bovine serum and with a purified chromatographic fraction containing LMWK, HMWK, and HMWK binding proteins.
  
  
  RESULTS
  Eleven aPE were serum dependent: mostly IgG (7/9) and some IgM (4/13). Among the 11 serum dependent aPE, all the 7 IgG and 2 IgM were kininogen reactive. Some serum independent IgM were better detected in the absence than in the presence of serum in the ELISA.
  
  
  CONCLUSIONS
  In the 18 patients, kininogens and/or HMWK binding proteins served as a "cofactor" significantly more often for aPE IgG than for aPE IgM (p = 0.007). Kininogen dependent aPE Ig were observed more often in patients with LR with or without TEE (6/8) than in those with SLE or primary APS (0/4) but this difference merely tended to significance (p = 0.06). In 2 patients, one with TEE, the other with primary APS, the IgM aPE was dependent on a serum "cofactor" that was not kininogen.
authors.affiliation: Unité INSERM U353, Hôpital St-Louis, Paris, France.
authors.forename: M C
authors.initials: MC
authors.lastname: Boffa
authors.forename: M
authors.initials: M
authors.lastname: Berard
authors.forename: T
authors.initials: T
authors.lastname: Sugi
authors.forename: J A
authors.initials: JA
authors.lastname: McIntyre
mesh_terms: D017152:Antibodies, Antiphospholipid / Q000097:blood* / Q000737:chemistry; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007132:Immunoglobulin Isotypes / Q000378:metabolism; D007704:Kininogens / Q000378:metabolism*; D016682:Lupus Coagulation Inhibitor / Q000097:blood; D008180:Lupus Erythematosus, Systemic / Q000276:immunology; D010714:Phosphatidylethanolamines / Q000276:immunology*; D017445:Skin Diseases, Vascular / Q000276:immunology; D013927:Thrombosis / Q000276:immunology
chemical_list: D017152:Antibodies, Antiphospholipid; D007132:Immunoglobulin Isotypes; D007704:Kininogens; D016682:Lupus Coagulation Inhibitor; D010714:Phosphatidylethanolamines