Less NK cell recovery after posttransplant cyclophosphamide-based allogeneic BMT predicts inferior survival. (A) Classification tree nodal selection at day 28 for OS showed that the only branch was formed by NK cells counts >50.5 cells/µL, which occurred in 82 patients (blue curves), counts were lower in 63 patients (red curves). The stopping rule included P value < .05 after Bonferroni testing, a minimum of 30 observations in a node, and a minimum of 15 observations in the terminal node. The P value in the figure is after Bonferroni correction. (B) The top curves show OS and PFS Kaplan Meier curves by the NK cell levels selected by the classification tree (>50.5 cells/µL vs ≤50.5 cells/µL). The bottom curves show the cumulative incidence curves for relapse and nonrelapse mortality (NRM) by NK cell levels selected by the classification. The blue curves represent recipients in whom NK cell counts at day 28 were >50.5 cells/µL, and the red curves represent the recipients with NK cell counts at day 28 ≤50.5 cells/µL.