Enhanced endothelial cell proliferation in acute Kawasaki disease (muco-cutaneous lymph node syndrome).

Paired sera from 30 patients with muco-cutaneous lymph node syndrome (Kawasaki disease) were studied for possible effects on human vascular endothelial cells growth in vitro. The majority of sera from acute phase muco-cutaneous lymph node syndrome patients significantly enhanced endothelial cell proliferation more than those from convalescent phase patients, infectious diseases patients, and age-matched normal controls. This stimulation was considered to be specific for EC since muco-cutaneous lymph node syndrome sera did not enhance fibroblast growth more than normal sera. Fractionation of the serum with gel filtration failed to clearly detect the molecular properties of this effect, although both heavy and light material possessed this activity. Extensive search for circulating immune complex in muco-cutaneous lymph node syndrome sera were negative, suggesting that the enhanced endothelial cell proliferation was due to serum components other than immune complexes.