Abstract
BACKGROUND: Kawasaki disease is an autoimmune disease characterized by systemic vasculitis of unknown aetiology and most commonly occurs in children under 5 years old. Previous studies have found that the over-activation of lymphocytes is an important mechanism of Kawasaki disease. Activin A, also known as immunosuppressive factor P, is a multifunctional growth and transforming factor. However, whether activin A is involved in the regulation of peripheral lymphocytes activity in Kawasaki disease is unclear. Thus, we aimed to investigate the effect of activin A on the activity of peripheral lymphocytes in acute-phase Kawasaki disease. METHODS: Seven patients with Kawasaki disease and seven healthy controls were studied. Peripheral blood lymphocytes were isolated by Ficoll density gradient centrifugation. The activation of CD4(+) and CD8(+) T cells and CD19(+) B cells was investigated by flow cytometry. The expression of activin type IIA receptors was investigated by flow cytometry. RESULTS: Immune imbalance in CD4 and CD8 lymphocytes were detected in acute-phase Kawasaki disease. The expression of activin type IIA receptors on CD8(+) T cells and CD19(+) B cells was increased in acute-phase Kawasaki disease and decreased following treatment with activin A. Activin A suppressed the expression of CD25 and CD69 on CD8(+) T cells and the expression of CD69 on CD19(+) B cells. CONCLUSIONS: The expression of activin type IIA receptor was increased on CD8(+) T cells and CD19(+) B cells in Kawasaki disease. Activin A suppressed the expression of CD25, CD69 and activin type IIA receptors on peripheral CD8(+) T lymphocyte. Activin A plays different roles in different lymphocyte subsets and suppresses peripheral CD8(+) T lymphocyte activity in acute-phase Kawasaki disease.