The role of bacterial lipopolysaccharide-bound neutrophils in the pathogenesis of Kawasaki disease.

To investigate the possible role of lipopolysaccharide (LPS, endotoxin) in the pathogenesis of Kawasaki disease, neutrophils from 15 patients with the disease and 7 with sepsis (4 infected with gram-negative bacteria and 3 with gram-positive bacteria) were analyzed by flow cytometry using anti-LPS and anti-CD14 monoclonal antibodies. The number of LPS- and CD14-positive neutrophils was dramatically higher early after the onset of Kawasaki disease and gram-negative sepsis but not with gram-positive sepsis. An immunoprecipitation analysis revealed LPS was bound to CD14 in vivo on neutrophils from Kawasaki disease patients. The mean plasma level of neutrophil elastase was significantly higher in the acute phase of Kawasaki disease than in the acute phase of sepsis. These findings suggest that exposure to LPS occurs at the onset of Kawasaki disease when LPS-bound neutrophils secrete excess protease (implicated in neutrophil-mediated endothelial injury) into the circulation.