Primary Study On Expression And Clinical Significance Of ReceptorNKG2A And NKG2D In The Peripheral Blood Of Lung Cancer Patients

OBJECTIVE:cellular immunity plays an important role in the anti-tumor immune.The role of NK cells in immune surveillance is essential. The previous study of lung cancer confined to the immune escape mechanism from NK cells in a single receptor, but the function of the NK cell is combined effected by a variety of receptors on its surface. The aim of the study is to observe combined detection the expression of inhibitory receptor NKG2A and activating receptor NKG2D by on NK cells in the peripheral blood in lung cancer, and to investigate the possible relationship between the imbalance expression of NKG2A and NKG2D and tumor immune escape and to make a discussion on the clinical significance. Aimed at understanding the role of NK cell surface inhibitory receptors and activating receptor expression and balance in the immune detection of lung cancer, and provide a theoretical basis for clinical diagnosis and immunotherapy.METHODS:The content of NK cells and the expression of NKG2A and NKG2D on NK cells in the peripheral blood were detected in101patients with lung cancer and81healthy controls by flow cytometry analysis. The association of NKG2A and NKG2D levels with clinical features was analyzed.RESULTS:(i) the content of NK cells in lung cancer group(18.99±6.22)%was significantly higher than that in the controls (16.81±6.64)%, with statistically significant difference (t=2.25, p=0.025)(ⅱ) The expression of NKG2A in lung cancer group (39.77±14.03)%was significantly higher than that in the controls (32.69±11.47)%, with statistically significant difference(t=-3.66, p=0.001)(ⅲ) The expression of NKG2D in lung cancer group was lower(84.23±4.20)%than that in the controls (85.16±3.61)%, but the differentiation of them had no statistical difference (t=1.59, p=0.112)(ⅳ) The ratio of NKG2A and NKG2D in lung cancer group (0.47±0.16) was significantly higher than that in the control (0.38±0.13).with statistically significant difference (t=-3.98, p=0.001)(ⅴ) In the lung cancer group, with the increase of TNM stagc(F=4.996,p=0.009) and PS grade(t=-2.01,p=0.041).the level of NKG2A also showed gradual increase, with statistically significant difference. The level of NKG2D had no correlation with TNM and PS grade, and NKG2A、NKG2D had no correlation with gender, age, primary tumor size, smoking, pathological types and the number of metastasis organs (p>0.05)(ⅵ) NKG2A-expressing on NK had a perfect negative correlation with NKG2D.CONCLUSION:(ⅰ) higher lever of NKG2A-expressing on NK cells and lower lever of NKG2D-expressing relatively in lung cancer patients, NKG2A/NKG2D ratio increases,Which suggests that The imbalance expression of NKG2A and NKG2D on NK cells in the peripheral blood in lung cancer may play important roles in lung cancer immunological surveillance.(ⅱ) NKG2A expression in lung cancer patients is closely related to TNM stage and PS score. As two immune markers they may be helpful in the evaluation of diagnosis and progression for lung cancer.(ⅲ) NKG2A-expressing NK had a perfect negative correlation with NKG2D. NKG2A may have a negative regulating function for the NKG2D activation, and make the inhibitory receptor in a dominant and relate to immune escape of tumor cells.