Histopathological aspects of cardiovascular lesions in Kawasaki disease.

Kawasaki disease (KD) is the commonest vasculitic syndrome. It affects medium-sized arteries, principally the coronary arteries. Histologically, coronary arteritis begins at 6 to 8 days after the onset of KD and the inflammation rapidly involves all layers of the artery. This results in severe damage to the structural components of the artery leading to arterial dilation. The inflammatory infiltrate in KD arteritis is characterized predominantly by infiltration of monocytes and macrophages. Activated neutrophils, monocytes and macrophages are believed to be involved in the initial stage of coronary arteritis. Inflammatory cell infiltration may continue for up to 25 days of disease following which the inflammatory cells gradually decline in number. Inflammatory lesions in the arteries are relatively synchronous as they evolve from an acute to the chronic stage. If a giant aneurysm remains or vessel recanalization occurs after thrombotic occlusion of an aneurysm, the remodeling of vascular structures may continue for a much longer time.