Reduced number of CD4⁺/CD25^bright regulatory T cells and increased Fas expression in ITP. Flow cytometric analysis of CD25 on CD3⁺/CD4⁺ T-helper cells and Fas on CD3⁺ T cells in peripheral blood (A,B) and bone marrow (C,D) from ITP patients (n = 6) and controls (n = 8). The results are given as percentage of T cells expressing CD25 and Fas. Data are presented as means (± SEM).