Enhanced neutrophilic functions in mucocutaneous lymph node syndrome, with special reference to the possible role of increased oxygen intermediate generation in the pathogenesis of coronary thromboarteritis.

To examine the possible correlation between mucocutaneous lymph node syndrome and thromboarteritis, we studied the capacity of polymorphonuclear leukocytes from 30 pediatric patients with mucocutaneous lymph node syndrome to generate oxygen intermediates and to release lysosomal enzymes. Cultured endothelial cells from human umbilical cord vein were also incubated with PMNs to assess oxygen intermediate-induced tissue injury. Within five days of MLNS onset, oxygen intermediate production, except for chemiluminescence generation, was markedly increased and the 51Cr release from labeled endothelial cells was significantly elevated. The lysosomal enzyme release was slightly, but significantly, higher. In the presence of superoxide dismutase and catalase, the 51Cr release was reduced to the control level, indicating the specificity of the effect of oxygen intermediate endothelial cell damage. At more than six to seven days after MLNS onset, the PMN functions were normal or decreased and the 51Cr release was reduced. In view of reports that coronary occlusion may appear one week after MLNS onset, we suggest that in the early stage of MLNS, a marked increase in oxygen intermediate generation induced by activated PMNs gives rise to coronary vascular injury, possibly leading to thromboarteritis and aneurysm formation.