Macrophages and cytotoxic T cells infiltrate the destructed mitral tissue in Kawasaki disease.

Kawasaki disease (KD) is an acute febrile systemic vasculitic syndrome especially affecting medium-sized arteries, including the coronary artery. Inflammation may involve all organs, and valvulitis is one of the cardiovascular complications that occurs in the acute phase of KD. However, details regarding the mechanism are unclear. An infant developed KD and severe mitral regurgitation with deformity and prolapse of the mitral tissue and underwent mitral valvotomy 1 year later. Histopathological study was conducted, and infiltrating cells consisted of mainly macrophages and cytotoxic T cells were found in resected mitral valve tissue. In addition, inflammation remained a long time after KD had developed.