OBJECTIVETo investigate the expression and prognostic value of memory T lymphocyte in patients with non-small cell lung cancer(NSCLC) following radiotherapy.

METHODSForty-six patients with NSCLC receiving radiotherapy in Ningbo Medical Center Lihuili Hospital from February 2010 to May 2012 were enrolled in the study and 50 healthy subjects served as the control group. The central memory T cell (T) and effector memory T cell (T) in peripheral blood CD4, CD8cells were detected by flow cytometry. Survival of patients was analyzed by Kaplan-Meier curve, and the relationship between clinical features, memory T lymphocyte changes and overall survival was analyzed by multivariate Cox regression model.

RESULTSCD4T, CD4T, CD8Tlevels and CD4/CD8Tof NSCLC patients were significantly lower than those of the control group, while CD4/CD8Twas significantly higher than that of the control group(all<0.05). In NSCLC patients, CD4T, CD4Tand CD8Twere decreased and CD8Tlevels were increased 4 weeks after radiotherapy(all<0.05); CD4T, CD4Tand CD8Tat 12-week after radiotherapy were increased significantly compared with those at 4-week after radiotherapy(all<0.05). Multivariate Cox regression analysis showed that the change of CD4Tafter radiotherapy was correlated with the overall survival (95%:1.135-2.994,<0.01). The survival rate and overall survival time for patients with decreasing CD4Twere 23.1% and 10.7 months (95%:0.29-12.41), while those of patients with stable CD4Twere 52.7% and 27.4 months (95%:0.00-31.26), and those of patients with increasing CD4Twere 66.4% and 37.4 months (95%:0.33-29.21), respectively.

CONCLUSIONSNSCLC patients show a significant immunosuppression at the initial stage after radiotherapy, and then a gradual improvement. Change of memory T lymphocyte after radiotherapy can be used to help predicting the prognosis of the patients.