Anti-interleukin 8 autoantibody:interleukin 8 immune complexes visualized by laser confocal microscopy in injured lung.
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.
Allen
Timothy Craig
TC
Department of Pathology, University of Texas Health Center, 11937 US Hwy 271, Tyler, TX 75708, USA.
Fudala
Rafal
R
Nash
Sandra E
SE
Kurdowska
Anna
A
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*
D000936:Antigen-Antibody Complex; D001323:Autoantibodies; D016209:Interleukin-8; D017452:Receptors, IgG