Kinetics of circulating blood percentage of total natural killer (NK) cells (A) and counts (B) of CD3−CD56+CD69+ NK subset in patients with septic shock during their stay in the intensive care unit. Values are expressed as the mean percentage ± standard deviation (A) or as the mean of cells per microliter ± standard deviation (B). Data from non-survival patients, survivors, and healthy control subjects are shown in red, green, and blue, respectively. The Mann-Whitney U test for non-parametric data was used to analyze differences between the groups, and analysis of variance followed by Wilcoxon signed-rank tests were used for within-group analyses. *P < 0.05 for survivors or non-survivors versus controls; †P < 0.05 for survivors versus non-survivors; ‡P < 0.05 for each follow-up time versus intensive care unit admission.