The effect of IL-2 (50 ng/mL = 100 U), IL-7 (5 ng/mL = 10 U), and IL-15 (10 ng/mL = 10 U) on the growth of the CTCL cell line SeAx. The withdrawal of these cytokines leads to cell death. The number of the cells is given in percent of the cell number used to start the cell culture (3 to 5 × 10⁵/mL) on the y-axis in a logarithmic scale. The time of incubation is given in days on the x-axis. The data were obtained from four independent experiments and standard variations were between 10% and 30%. Note that the number of cells is given on a logarithmic scale, so that standard deviations of 10% to 30% are not visible.