A swine model of horse serum-induced coronary vasculitis: an implication for Kawasaki disease

An attempt was made to induce immune complex vasculitis by horse serum (HS) infusions in piglets, hoping to produce experimental coronary artery lesions that mimic Kawasaki disease. A total of 21 purebred male piglets of 1.5, 2.5, and 3 mo were divided into HS (n = 14) and control, normal saline (NS; n = 7) groups. In seven piglets, 5 mL/kg of HS was infused, then repeated with 10 mL/kg 10 d later. In another seven piglets, 10 mL/kg of HS was infused three times at 5-d intervals. In three piglets in the control group, 5 and 10 mL/kg of NS was infused at 10-d intervals. In another four piglets of the control group, 10 mL/kg of NS was infused three times at 5-d intervals. Two-dimensional echocardiographic examinations for visualization and measurement of the coronary arteries were done before and after infusions at 4- to 5-d interval. Hematology examination showed that white blood cells and platelets decreased, then increased. The animals were killed at 14-60 d after the first infusion of HS or NS, for histopathologic and immunohistochemical studies. All HS groups developed skin rashes and echocardiographic evidence of coronary artery dilation and histopathologic changes of vasculitis. None in the NS group developed vasculitis. The main changes of the coronary vasculitis were intimal proliferation, smooth muscle cell necrosis, and vacuolization changes. Those that received three HS infusions developed more skin rashes than those that received two infusions. It is concluded that piglets may serve as an experimental model for immune complex vasculitis involving the coronary arteries with skin rashes mimicking Kawasaki disease.