CD25+ CD4+ regulatory T cells in patients with Kawasaki disease

Objective To investigate whether the CD25(+)CD4(+) regulatory T-cell population, which plays important roles not only in maintaining immunologic self-tolerance but also in controlling the magnitude and character of antimicrobial immune responses, is related to the pathophysiology of Kawasaki disease (KD). Study design The patient group consisted of 54 patients (median age, 30 months; 27 female and 27 male patients) fulfilling the criteria for KD. Age-matched control subjects included 17 patients with active infections and 24 healthy children. We. analyzed CD25(+)CD4(+) cells and the mRNA expression of Foxp3, cytotoxic T lymphocyte-associated antigen 4 (CTLA4), glucocorticoid-induced tumor necrosis factor receptor (GITR), and transforming growth factor beta in peripheral blood mononuclear cells and purified CD4(+) T cells. Results The proportions of CD25(+)CD4(+) cells inpatients with acute-phase KD (median, 2.35% of total lymphocytes) were significantly lower than those in healthy control subjects (median, 3.14%) and control subjects with disease (median, 3.15%). The proportions returned to the normal level after intravenous gammaglobulin treatment (median, 3.86%). The mRNA expression of Foxp3, CTLA4, and GITR showed similar tendencies. Conclusions The decrease of CD25(+)CD4(+) regulatory T cells in the acute phase might have a role in the development of KD.