Objective To explore the effects of precoated RetroNectin on the proliferation and cytotoxicity of natural killer cells(NK) from acute leukemia (AL).Methods Mononuclear cells (MNCs)were isolated from peripheral blood of complete remission AL patients.The MNCs were cultured in vitro precoated with 50 μg/ml RetroNectin ( group Ⅰ ),25 μg/ml RetroNectin (group Ⅱ ) and by the raditional method (control group) to generate NK.The changes of growth rate,phenotypic characterization,secretion of cytokines of NK,cell cycle,apoptosis and cytotoxicity of NK were determined.Results The amplification of NK in group Ⅰ ( (51 ±9) × 106 ) and Ⅱ ( (79 ± 16) × 106 ) were higher than that in control group( (37 ±11 ) × 106 ) ( both P ＜ 0.05 ),and the amplification of NK in group Ⅱ was higher than that in group Ⅰ ( P ＜0.05).There were no differences among three groups with regards to the phenotypic characterization of CD3- CD56 +.The secretions of interleukin 2,interleukin 12,tumor necrosis factor alpha and interferon gamma in group Ⅰ and Ⅱ were higher than that in control group( all P ＜ 0.05 ).The expression of CD25 positive cells in groups Ⅰ (38.2％ ±4.1％ ) and Ⅱ (37.5％ ±5.1％ ) were higher than that in control group(24.2％ ±5.8％ ) (both P ＜0.05).The expression of NKG2D positive cells in groups Ⅰ (81.6％ ±17.9％ ) and Ⅱ (85.7％ ± 20.1％ ) were higher than that in control group (63.6％ ± 21.9％ ) ( both P ＜0.05 ).The percentages of G1 stage cells in groups Ⅰ (50％ ± 10％ ) and Ⅱ (49％ ± 11％ ) were lower than that in control group(71％ ± 15％ ) while the percentages of S stage cells in groups Ⅰ (36％ ± 14％ ) and Ⅱ( 37 ％ ± 8 ％ ) were higher than that in control group ( 19％ ± 10％ ) ( all P ＜ 0.05 ).But no difference existed between two groups (all P ＞ 0.05).The expression of cell cycle regulatory genes p21 and p27 were reduced in groups Ⅰ and Ⅱ.The percentages of apoptotic cells in groups Ⅰ ( 10.7％ ± 2.1％ ) and Ⅱ (9.4％ ±3.1％ )were lower than that in control group(29.6％ ± 10.3％ ) (both P ＜0.05).The cytotoxicity to AL cells in groups Ⅰ (82％ ±21％ ) and Ⅱ (80％ ± 18％ )were higher than that in control group (61％ ± 14％ )(both P ＜ 0.05 ) at the E/T scope 20 ∶ 1. But no difference existed between two groups ( all P ＞ 0.05 ).Conclusion The proliferation and cytotoxicity of NK cells may be boosted by precoated RetroNectin.