title: Anti-interleukin 8 autoantibody:interleukin 8 immune complexes visualized by laser confocal microscopy in injured lung.
abstract: BACKGROUND
  Anti-interleukin 8 autoantibody:interleukin 8 (anti-IL-8 autoantibody:IL-8) complexes are present in lung fluids of patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS), and levels of these complexes correlate with progression to and the outcome of ARDS. Fc gammaRIIa, an immunoglobulin G (IgG) receptor, mediates proinflammatory activity of the complexes.
  
  
  OBJECTIVE
  To evaluate lung tissues from patients with ARDS for presence of anti-IL-8 autoantibody:IL-8 complexes and to establish whether the complexes associate with Fc gammaRIIa.
  
  
  METHODS
  Lung tissue sections from 3 patients with ARDS and sections of normal lung tissues from 3 patients were stained with antibodies against IL-8 and IgG to detect immune complexes and with antibody against Fc gammaRIIa. In some experiments, sections were blocked with anti-Fc gamma RIIa antibody before staining. Samples were analyzed using confocal microscopy.
  
  
  RESULTS
  Interleukin 8 costained with IgG and Fc gammaRIIa in lung tissues from patients with ARDS but not in control tissues, suggesting that anti-IL-8 autoantibody:IL-8 complexes are deposited in lungs of patients with ARDS via Fc gammaRIIa. Further, colocalization between IL-8 and Fc gammaRIIa could be blocked by anti-Fc gammaRIIa.
  
  
  CONCLUSIONS
  Our data demonstrate that anti-IL-8 autoantibody:IL-8 complexes are present in lung tissues of patients with ARDS, and are attached to Fc gammaRIIa.
authors.affiliation: Department of Pathology, University of Texas Health Center, 11937 US Hwy 271, Tyler, TX 75708, USA.
authors.forename: Timothy Craig
authors.initials: TC
authors.lastname: Allen
authors.forename: Rafal
authors.initials: R
authors.lastname: Fudala
authors.forename: Sandra E
authors.initials: SE
authors.lastname: Nash
authors.forename: Anna
authors.initials: A
authors.lastname: Kurdowska
mesh_terms: D000936:Antigen-Antibody Complex / Q000032:analysis*; D001323:Autoantibodies / Q000032:analysis*; D016022:Case-Control Studies; D006801:Humans; D016209:Interleukin-8 / Q000032:analysis / Q000276:immunology* / Q000378:metabolism; D008168:Lung / Q000276:immunology*; D018613:Microscopy, Confocal; D017452:Receptors, IgG / Q000032:analysis / Q000378:metabolism; D012128:Respiratory Distress Syndrome / Q000276:immunology*
chemical_list: D000936:Antigen-Antibody Complex; D001323:Autoantibodies; D016209:Interleukin-8; D017452:Receptors, IgG