Kaplan-Meier curves. Deciles from percentile 10 to percentile 90 of natural killer (NK) cell counts measured at day 1 were calculated and used to compare survival times in those patients with low or high concentrations of NK cells in their blood. The first decile shows significant differences between groups based upon the log-rank test (Mantel-Haenzel) and was used as the cutoff (percentile 60 (83 cells/mm3)). Outcome for this analysis was time until death. Time was censored at day 28. Cum Surv: cumulative survivors; NK: natural killer.