Selective expansion of T cells expressing T-cell receptor variable regions V beta 2 and V beta 8 in Kawasaki disease.

Kawasaki disease (KD) is an acute vasculitis complicated by the development of coronary artery abnormalities. The etiology of KD is unknown. Based on the observation that KD is associated with marked activation of T cells and monocyte/macrophages, we hypothesized that KD may be caused by a superantigen [e.g., a bacterial toxin that stimulates T cells expressing particular T-cell receptor beta chain variable (V beta) gene segments]. Peripheral blood T cells from patients in the acute and convalescent phases of KD and from various control groups were analyzed for T-cell receptor V beta gene expression by using a quantitative PCR technique and cytofluorographic analysis with available anti-V beta monoclonal antibodies. Patients with acute KD demonstrated significantly elevated levels of circulating V beta 2+ and V beta 8.1+ T cells compared to the other control groups. none of the other 20 V beta populations analyzed by quantitative PCR were found to be significantly elevated. Using flow cytometry, we confirmed a significant elevation of T cells reactive with anti-V beta 8.1 and the lack of change in several other V beta subsets--i.e. V beta 5.1, -5.2, -6.7, and -12. During the convalescence phase of KD, there was a reduction in the abnormal levels of V beta 2+ and V beta 8.1+ T cells. These observations suggest that KD may be caused by a superantigen and may provide insight into the nature of the etiologic agent.