Abstract: ［Abstract］Objective To investigate the changes and clinical significance of natural killer（NK） cell activating receptors and inhibitory receptors in patients with non-small cell lung cancer before and after chemotherapy.
Methods Fifty patients with non-small cell lung cancer(25 cases each in stages Ⅰ- ⅢA and ⅢB- Ⅳ) and 10 healthy subjects(control group) were selected. Flow cytometry was used to detect peripheral blood NK cell activating receptors NKG2D, NCRs(NKp30, NKp44, NKp46) and inhibitory receptors CD158a, CD158b, CD158e, and receptor expression after two cycles of chemotherapy of stages ⅢB to Ⅳ. CD56dim and CD56bright were counted according to the expression intensity of CD56.
Results The CD56dim activated receptors NKG2D and NKp30 in patients with stage ⅢB-Ⅳ in non-small cell lung cancer were lower than those in healthy subjects and patients in stage Ⅰ-ⅢA, the expression of CD56dim activated receptor NKp44 of non-small cell lung cancer  in stage Ⅰ- ⅢA and  ⅢB- Ⅳ was lower than that of healthy subjects(P＜0.05). There was no significant difference between three groups in CD56dim activated receptor NKp46(P＞0.05). There was no significant difference between the three groups in the expression of NKG2D, NKp30, NKp44 and NKp46(P＞0.05). There was no significant difference in the CD56dim inhibitory receptors CD158a, CD158b, CD158e and CD56bright inhibitory receptors CD158a, CD158b, and CD158e in three groups(P＞0.05). Due to the lack of enrolled staff, 14 patients were enrolled after two cycles chemotherapy of stage ⅢB to Ⅳ. The percentages of CD56dim activated receptors NKp30 and NKp44 in patients with stage ⅢB- Ⅳ non-small cell lung cancer after chemotherapy were higher than those before treatment(P＜0.05). After chemotherapy, CD56dim activating receptors NKp46, NKG2D and inhibitory receptors CD158a, CD158b, CD158e were not statistically different from those before chemotherapy(P＞0.05). After chemotherapy, there was no significant difference in the activation receptor NKp30, NKp44, NKp46, NKG2D and the inhibition receptor CD158a, CD158b and CD158e between two groups(P＞0.05). After 2 cycles of chemotherapy, the PR rate of 14 patients reached 78.5%(11/14).
Conclusion The decreased expression of activated receptors in CD56dim NK cells in stage ⅢB-Ⅳ may be related to the decreased cytotoxicity of activated receptors on NK cells caused by tumor microenvironment. After chemotherapy, the expression of NKp30 and NKp44 can be increased. It is speculated that chemotherapy can play its killing effect on tumor by improving the activity of NK cells.

Key words: carcinoma, non-small-cell lung, killer cells, natural, drug therapy