Pediatric Cardiology and Cardiac Surgery
Vol.24 No.1 2008 (3-10)
Division of Cardiology, Tokyo Metropolitan Kiyose Children’s Hospital, Tokyo, Japan
The etiology of Kawasaki disease, although unknown, is likely to be a ubiquitous microbial agent. IgA plasma cells infiltrate coronary arterial and other inflamed tissues in acute Kawasaki disease (KD), and they are significantly increased in the upper respiratory tract of patients with KD, compared with those in control subjects. Macrophages and CD8 T-lymphocytes are prominent in the inflammatory infiltrate. IgA genes in arteries from KD patients are oligoclonal, that is, they are antigen driven. Oligoclonal antibodies synthesized in vitro identify antigen in acute KD, but not in control, bronchial epithelial cells, and the antigen resides in cytoplasmic inclusion bodies that are consistent with aggregates of viral proteins and associated nucleic acid. The synthetic antibodies also detected the antigen in a subset of macrophages in inflamed acute KD tissues such as the coronary artery aneurysms as well as the gastrointestinal tract with marked inflammation. These findings suggest that KD is caused by a previously unidentified respiratory infectious agent that spreads through the bloodstream, potentially within macrophages, to the target tissues of KD, particularly the coronary arteries.