High proportion of Circulating CD8+CD28- senescent T cell in an independent predictor of distant metastasis in Nasopharyngeal Cancer after radiotherapy

Abstract Background : Nasopharyngeal Cancer is a kind of epithelial carcinoma, and common in east and southeast Asia. Distant metastasis after radiotherapy remains the main cause of treatment failure and immune system function. Methods : To explore the immune-related prognostic factors, in our study we explored the immune cells in peripheral blood from total 332 nasopharyngeal carcinoma patients, in these immune cells, we include the CD8+CD28− T cells which is a unique T cells immunosenescent subset increased in human peripheral blood with increasing age and declining immune function. We first divided our cohort into training and validation cohort, and utilized flow cytometry to investigate the immune cells in peripheral blood of patients with nasopharyngeal carcinoma. Based on the results and clinical information, we utilized Cox regression and LASSO regression model to screen the PFS and DMFS prognostic factors in training cohort and used validation cohort to verify the results. Results : Based on the prognostic factors we built nomograms to predict PFS and DMFS after radiotherapy and validated. Post treated EBV and the proportion of CD8+CD28-T cells were selected to predict PFS. Post treated EBV, the proportion of CD8+CD28-T cells and N stage were selected to predict DMFS. We also explored the expression in the different stage and the correlation between the proportion of CD8+CD28-T cells and systemic inflammation, post-treated immunosuppression. Conclusion : All nomograms model we build have good predictive value. Proportion of CD8+CD28-T cells is a candidate prognostic biomarker for nasopharyngeal carcinoma.