title: Identification of polyclonal and monoclonal antibodies against tissue plasminogen activator in the antiphospholipid syndrome.
abstract: OBJECTIVE
  To test the hypotheses that some plasmin-reactive anticardiolipin antibodies (aCL) may bind to tissue plasminogen activator (tPA) and that some of the tPA-reactive aCL may inhibit tPA activity.
  
  
  METHODS
  We studied the reactivity of 8 patient-derived monoclonal aCL with tPA and examined the presence of IgG anti-tPA antibodies in patients with the antiphospholipid syndrome (APS). The effects of the reactive monoclonal aCL on the activity of tPA were also examined.
  
  
  RESULTS
  Six patient-derived plasmin-reactive monoclonal aCL bound to tPA. Analysis of plasma samples revealed that 10 of 80 APS patients (12.5%) and 1 of 81 systemic lupus erythematosus patients (1.2%) had antibodies against fibrin-associated tPA, based on a cutoff value equal to the mean + 2SD of the level in 28 normal subjects. Of the 6 tPA-reactive monoclonal aCL, 2 of them (CL1 and CL15) inhibited tPA activity.
  
  
  CONCLUSIONS
  Some of the plasmin-reactive aCL in APS patients may bind to tPA. Of the tPA-reactive aCL, some (such as CL1 and CL15) may inhibit tPA activity and, thus, may be prothrombotic in the host.
authors.affiliation: University of California, Los Angeles, CA 90095, USA.
authors.forename: Cai-Sheng
authors.initials: CS
authors.lastname: Lu
authors.forename: Arash A
authors.initials: AA
authors.lastname: Horizon
authors.forename: Kwan-Ki
authors.initials: KK
authors.lastname: Hwang
authors.forename: John
authors.initials: J
authors.lastname: FitzGerald
authors.forename: Wei-Shiang
authors.initials: WS
authors.lastname: Lin
authors.forename: Bevra H
authors.initials: BH
authors.lastname: Hahn
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Wallace
authors.forename: Allan L
authors.initials: AL
authors.lastname: Metzger
authors.forename: Michael H
authors.initials: MH
authors.lastname: Weisman
authors.forename: Pojen P
authors.initials: PP
authors.lastname: Chen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017153:Antibodies, Anticardiolipin / Q000097:blood / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000097:blood / Q000276:immunology*; D000918:Antibody Specificity; D016736:Antiphospholipid Syndrome / Q000276:immunology* / Q000378:metabolism; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000276:immunology; D010959:Tissue Plasminogen Activator / Q000276:immunology* / Q000378:metabolism
chemical_list: D017153:Antibodies, Anticardiolipin; D000911:Antibodies, Monoclonal; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D010959:Tissue Plasminogen Activator