Interleukin 8 in plasma is an efficacy marker for advanced non-small cell lung cancer treated with hypofractionated radiotherapy and PD-1 blockade.

Abstract

Programmed death-1 (PD-1) blockade promotes combination therapy in advanced non-small cell lung cancer (NSCLC), hypofractionated radiotherapy (HFRT) and chemotherapy combined with immunotherapy improves the outcome of prognosis in advanced NSCLC, while effective biomarkers to follow prognostic efficacy are still to be found. We enrolled 44 NSCLC patients with HFRT combined with PD-1 blockade, 13 patients with chemotherapy combined with immunotherapy, additionally collected tissue samples from 8 patients with earlystage NSCLC without therapy, and peripheral whole blood from 16 healthy donors, detected the expression differences of cytokines Interleukin 6 (IL-6), Interleukin 8 (IL-8) and Interleukin 17A (IL-17A) in the peripheral plasma and tissues by flow cytometry, immunofluorescence, and real-time fluorescence quantitative PCR. Cultured peripheral blood mononuclear cell (PBMC) and tumor-infiltrating T cells with recombinant human IL-8 in vitro to observe the changes of immune memory T cell subtypes and apoptosis. Our results show that IL-6, IL-8, and IL-17A are highly expressed in advanced NSCLC, high levels of IL-8 are significantly associated with poor prognosis in advanced NSCLC patients treated with HFRT+PD1 blockade, high circulating IL-8 in NSCLC increased apoptosis of effector memory RA (TemRA; CD45RA+CCR7-) T cell subsets and CD8+ T cell subsets in tissues, resulting in decreased peripheral TemRA and stem cell-like memory T cells (TSCM: CD45RA +CCR7 + CD95 +) in tissue. We suggest that IL-8 can impair immune memory function in NSCLC. It is a useful biomarker to evaluate the efficacy of HFRT+PD1 blockade in advanced NSCLC. Further exploration of easily available plasma biomarkers for personalized treatment of NSCLC is required.