TCR V beta family repertoire and T cell activation markers in Kawasaki disease.

Kawasaki disease (KD) is the leading cause of acquired heart disease in children in the United States. The etiology is unknown. Data regarding the presence of T cell activation and its potential role in the pathogenesis of the disease have been conflicting. Expansion of T cells bearing V beta 2 and V beta 8 has recently been reported in the acute phase of KD, which suggests that a superantigen may mediate the disease process. To further assess the potential role of T cells in KD, T cell phenotypes were evaluated by using flow cytometry in a large series of patients, acutely and during convalescence. Included in this analysis were assessments of changes in the percentage of T cells bearing TCR V beta 2, V beta 5.1, V beta 6.7, V beta 8, V beta 12.1, and V beta 19 over time; the percentage of each V beta family bearing the activation markers HLA-DR and IL-2R; and the percentage of each V beta family bearing the memory marker, CD45RO. No expansion of any V beta family was present acutely, nor were increases in HLA-DR and IL-2R observed. However, a significant increase was observed during convalescence in the percentage of cells bearing CD45RO in the CD8+, but not the CD4+, population. CD45RO expression was also increased on V beta 2, V beta 8, and V beta 19 CD8+ T cells in a subset of patients. These data suggest that one or more conventional Ags drive the T cell immune response in KD, and argue against a role for superantigens in the disease process.