Purpose: The aim of this study was to investigate the prognostic significance of the absolute natural killer (NK) cell counts in peripheral blood in patients with chronic lymphocytic leukemia (CLL).
Methods: A total of 273 previously untreated patients with CLL from April 2004 and October 2015 were enrolled into this retrospective study. We analysed the T cell subsets of all patients and figured out the number of NK cells. Comparisons of NK cell count as continuous parameter in different groups were described using Mann-Whitney U test and the Kruskal-Wallis test. Kaplan-Meier method was used to survival analysis, and the Cox proportional hazards models were used for the estimation of prognostic factors.
Results: NK cell counts were calculated in 273 therapy-naive CLL patients, and higher number of NK cell was observed in those with Binet stage A/B, ZAP-70 < 20%, normal serum albumin and β2-microglobulin levels. Using a NK cell count cut-off of 0.40 × 109/L, patients with lower NK cell count (< 0.40 × 109/L) had a significantly shorter overall survival (OS) than those with higher NK cell count (≥ 0.40 × 109/L) (P = 0.0014). Multivariate analysis showed that NK cell counts remained its prognostic value. However, the effect of NK cell count on time to treatment was not significant.
Conclusions: Our results suggest that NK cell count is an independent prognostic marker for OS in patients with CLL and NK cell counts ≥ 0.40 × 109/L can routinely be used to identify patients with favorable survival.
Keywords: Absolute NK cell count; Chronic lymphocytic leukemia; Dynamic; Host immunity; Prognosis.