| Purpose:Radiation-induced lymphocytopenia is very common in clinical practice.In recent years,studies in different cancer types have formed a consensus that radiation-induced lymphocytopenia is closely related to the long-term prognosis of patients,who with severe lymphocytopenia induced by radiation have poor survival time.From the immunological point of view,lymphocytes,as an important part of the immune system,participate in the body’s innate immunity and adaptive immune response,indicating that radiation-induced lymphocyte reduction is one of the manifestations of immune editing state imbalance.Compared with lymphocytes,peripheral blood immune cells can more comprehensively reflect the characteristics of patients’ peripheral blood immune environment during treatment.On the one hand,radiation-induced lymphocyte reduction can be further stratified and analyzed;on the other hand,we can provide more therapeutic clues for improving patients’ immune function.We attempted to study the dynamic peri-radiation characteristics and prognostic value of the abundance of peripheral blood immune cell and cytokine for gastrointestinal cancers,and to reveal the difference of radiosensitivity and recovery post-radiation ability of different immune cells.Methods:We retrospectively collected the medical records of 61 patients with gastrointestinal tumors who received intensity modulated radiotherapy in Zhujiang Hospital of Southern Medical University from January 2019 to February 2021.We analyzed the concentration of immune cells and cytokines in peripheral blood before radiation,during the radiation,the end of the radiation and post-radiation 1 month using flow cytometry instrument.Two independent sample nonparametric tests and two related sample nonparametric tests were used to analyze the characteristics of peripheral blood immune environment;Univariate and multivariate logistic regression analysis were used to determine the immune factors that could affect tumor regression response.Bivariate correlations were used to analyze clinical variables associated with immune factors.The correlation of the interaction between different baseline indicators and immune factors with outcome variables were analyzed using interaction effects.Results:1)There are no significant statistical differences for the concentration of peripheral immune cells between the radiotherapy group and synchronous one which appeared a downward trend when radiation started,adding synchronization did not increase toxicity to cells injury.However,the restored ability of immune cells in synchronous group was lower than radiotherapy one,proved the radiotherapy is the main factor for treatment-related immunocytopenia.2)In terms of radiosensitivity,we found that all factors showed consistent trends by statistics analysis for patients with peripheral immune after the start of radiation.In terms of the recovery ability after radiation,there are differences in the recovery ability of immune cells.Among them,the levels of peripheral blood B cells and CD4+T cells did not show a significant upward trend post-radiation 1 month,while CD8+T cells,CD45+T cells,CD4+8+T cells,NK cells and T cells all gradually increased after radiotherapy.However,CD8+T cells returned to baseline the fastest.3)There was no separation of immune cells in peripheral blood in response-group patients(CR,PR)and nonresponse group(SD,PD).In the response group,the concentration of different cytokines in the peri-radiotherapy period showed no fluctuation and remained stable.The non-response group showed an increasing trend.Consistent with this,peripheral blood IFN-y levels were significantly correlated with tumor objective response rate(ORR).Logistic regression analysis showed that higher IFN-y concentration in peripheral blood 1 month after radiotherapy(OR=0.567,95%CI 0.360-0.891,p<0.05)was an independent prognostic factor for poor prognosis.The AUC of IFN-y concentration between the two groups was 0.817.When the concentration of IFN-y in peripheral blood was 4.965pg/mL,the sensitivity and specificity were 61.7%and 92.9%,respectively.4)The concentrations of CD4+T cells and B cells in peripheral blood of the responding group(CR,PR,SD)and the non-responding group(PD)showed a separation.The concentrations of CD4+T cells and B cells in peripheral blood of the responding group continued to decrease,while the concentrations of CD4+T cells of the non-responding group gradually increased.There was no significant difference in cytokines between the two groups.Similarly,we found that the concentration of CD4+T cells during radiation was significantly correlated with disease control rate(DCR).Logistic regression analysis showed that higher concentration of CD4+T cells in peripheral blood(OR=0.567,95%CI 0.360-0.891)was an independent prognostic factor for poor prognosis.Higher peripheral blood CD4+T cell concentration in the middle of radiotherapy(OR=1.010,95%CI 1.0021.018,p<0.05).The AUC of CD4+T cells between the two groups was 0.691.When the concentration of CD4+T cells in peripheral blood was 281.5 N/μL,when the Jorden index was the largest.Conclusion:Peripheral blood immune cells and cytokines have predictive value for patients with different tumor shrinkage degree during peri-radiotherapy. |
