P16.01 The Effect of Different Dose and Sites of Irradiation on Lymphocyte Subsets in Peripheral Blood of Patients With Lung Cancer

Abstract

To explore the effect of different irradiation doses and sites on systemic immunity in patients with lung cancer by detecting the changes in the percentage of lymphocyte subsets in peripheral blood before and after radiotherapy. Peripheral blood in 48 patients with lung cancer receiving radiotherapy were collected (before, during and after radiation), and the lymphocyte subsets as follow were examined: total T cell (CD3+) , CD4+T cell , CD8+T cell , CD3+CD4+/CD3+CD8+, natural killer cell, memory T-helper cell subpopulation (CD4+ CD45RO+), CD4+ naïve T-cell subset (CD4+CD45RA+), cytotoxic T cell (CTL) (CD8+CD28+), interleukin-2 (IL-2) receptor α(CD25+), B cells (CD3-CD19+) , regulatory T cells (CD4+CD25+). The results were statistically analyzed with unpaired Student's t-test using GraphPrism6 software. Among non-small cell lung cancer (NSCLC) patients treated with thoracic radiation (n = 21), B cells in patients receiving 20Gy/10F (P = 0.0072), 40Gy/ 20F (P = 0.0001), 60Gy/30F (P = 0.0002) irradiation were significantly lower than that before radiotherapy. However, CD4+ naïve T-cells decreased significantly at each dose point compared with that before radiotherapy, P values were 0.0394, 0.0081 and 0.0007, respectively. NK cells after completion of 60Gy/30F irradiation were distinctly lower than those after receiving 20Gy/10F of radiotherapy (P = 0.0278), and no significant difference was found in other immune cell subsets. Patients with small cell lung cancer (n=6) who underwent thoracic radiation showed a similar trend of changes in B cells. However, the CD4+CD45RA+ subset decreased evidently after completing radiation compared with that after 10 fractions of irradiation (P=0.0390). The NSCLC patients (n=4) who received irradiation for bone metastases (regimen: 36Gy/12F) had evidently lower B cells (CD3-CD19+) at the end of radiotherapy than that at the start of radiotherapy (P=0.0286). Patients with NSCLC (n=10) who received brain radiation (regimen: 40Gy/20F for whole brain, 54-56Gy/20F for multiple brain metastases) had a significantly reduced CD4+CD45RA+ subsets after finishing irradiation (20F) compared with those after 10 fraction of radiotherapy (P= 0.0497). The changes of other subsets were not statistically significant. The effect of radiation in different sites and doses on peripheral blood lymphocyte subsets is not identical. It is necessary to further expand the sample size to explore the law for the optimization of radiotherapy combined with immunotherapy. Funding: 81972853, 81572279, 2016J004, LC2019ZD009, 2018CR033.