title: Agonistic anti-ICAM-1 antibodies in scleroderma: activation of endothelial pro-inflammatory cascades.
abstract: BACKGROUND
  Scleroderma (SSc) is a complex autoimmune disorder that can be characterised by the presence 2of circulating autoantibodies to nuclear, cytoplasmic and cell surface antigens. In particular antibodies directed against endothelial cell antigens (anti-endothelial cell antibodies; AECA) have been detected. ICAM-1 is an adhesion molecule expressed on the surface of human endothelial cells. We have previously shown that cross-linking ICAM-1 with monoclonal antibodies leads to pro-inflammatory activation of human endothelial and vascular smooth muscle cells and that cardiac transplant recipients with transplant associated vasculopathy make antibodies directed against ICAM-1.
  
  
  OBJECTIVE
  To determine whether SSc patients make antibodies directed against ICAM-1 and whether these antibodies induce pro-inflammatory activation of human endothelial cells in vitro.
  
  
  METHODS
  Using recombinant ICAM-1 as capture antigen, an ELISA was developed to measure ICAM-1 antibodies in sera from SSc patients. Antibodies were purified using ICAM-1 micro-affinity columns. HUVEC were incubated with purified anti-ICAM-1 antibodies and generation of reactive oxygen species, and expression of VCAM-1 was measured.
  
  
  RESULTS
  Significantly elevated levels of anti-ICAM-1 antibodies were detected in patients with diffuse (dSSc; 10/31 32%) or limited (lSSc; 14/36 39%) scleroderma. Cross-linking of HUVEC with purified anti-ICAM-1 antibodies caused a significant increase in ROS production (2.471±0.408 fold increase above untreated after 150 min p<0.001), and significant increase in VCAM-1 expression (10.6±1.77% vs 4.12±1.33%, p<0.01).
  
  
  CONCLUSIONS
  AECA from SSc patients target specific endothelial antigens including ICAM-1, and cause pro-inflammatory activation of human endothelial cells, suggesting that they are not only a marker of disease but that they contribute to its progression.
authors.affiliation: Department of Comparative Biomedical Sciences, The Royal Veterinary College, London, UK.
authors.forename: Sabine I
authors.initials: SI
authors.lastname: Wolf
authors.forename: Sarah
authors.initials: S
authors.lastname: Howat
authors.forename: David J
authors.initials: DJ
authors.lastname: Abraham
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Pearson
authors.forename: Charlotte
authors.initials: C
authors.lastname: Lawson
mesh_terms: D000906:Antibodies / Q000097:blood / Q000276:immunology*; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D001327:Autoimmune Diseases / Q000097:blood / Q000276:immunology; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000276:immunology*; D004730:Endothelium, Vascular / Q000276:immunology*; D061307:Human Umbilical Vein Endothelial Cells / Q000276:immunology; D006801:Humans; D007249:Inflammation / Q000276:immunology*; D018799:Intercellular Adhesion Molecule-1 / Q000276:immunology*; D017382:Reactive Oxygen Species / Q000276:immunology; D045743:Scleroderma, Diffuse / Q000097:blood / Q000276:immunology*; D045745:Scleroderma, Limited / Q000097:blood / Q000276:immunology*; D019010:Vascular Cell Adhesion Molecule-1 / Q000276:immunology
chemical_list: D000906:Antibodies; D001323:Autoantibodies; D017382:Reactive Oxygen Species; D019010:Vascular Cell Adhesion Molecule-1; C087589:anti-endothelial cell antibody; D018799:Intercellular Adhesion Molecule-1
keywords: Autoantibodies; ICAM-1; Systemic sclerosis; Vascular inflammation