Severe-grade neutropenia is associated with the NK^imm phenotype. (A,C) Clinical data for the NP and NK^imm groups, presented as frequency of total group. (B) Frequency of CD56^bright NK cells for NP and NK^imm groups divided by G-CSF treatment (−, no treatment; +, patients on G-CSF, but with scheduled stop in treatment). (D) Spearman rank correlations for NK^imm-defining parameters and ANCs. (E) Frequency of CD56^bright NK cells divided by severity of neutropenia within the NK^imm group. (F) Documented grade 1 to 3 infection history in patients in the NP and NK^imm groups with severe-grade neutropenia. HD (n = 20), NP (n = 39), and NK^imm (n = 14). *P < .05; **P < .01 by nonparametric test and χ² test for trend.