Memory and naive T cells. (A-D) Percentages of CD4 (A-B) and CD8 (C-D) cells staining with CD45RA and CD62L (A,C) or CD45RO (B,D) at diagnosis and at 5 points during therapy. Points represent median values; error bars, interquartile range. Phases of treatment are shown by the bars below (▪ indicates induction; ▨, consolidation; and □, maintenance). Gray band represents 10th to 90th percentiles for healthy children and the dotted line represents the median. (E-F) Ratio of CD45RO to CD45RA/CD62L cells in the CD4 (E) and CD8 (F) T-cell compartments with respect to age. Ratio is plotted on a log scale. Circles represent mean values for individual patients obtained at diagnosis and during therapy. Gray band represents 10th to 90th percentiles of age-specific ratios, and the dotted line represents the median for healthy children.