Frequency of CD4⁺CD25^hi T cells in context of stage of disease in previously untreated CLL patients. Patients were classified according to the Binet classification: Binet A (n = 9), Binet B (n = 13), and Binet C (n = 4). Shown here are median, 75 percentile (box), SD (whiskers), and outliers (dots) of data obtained by multicolor flow cytometry.