Changes in lymphocyte and monocyte cell frequencies following overnight resting of cells. Infant (left) and adult (right) cell viability (A and B) and percentages of total live CD4+ (C and D), CD8+ (E and F), and CD14+ (G and H) cells after a 2-h or overnight rest. Lines show median values. Asterisks indicate significant differences (Wilcoxon matched-pairs signed-rank test): *, P < 0.05; ***, P < 0.001. Infants, n = 10; adults, n = 12.