Peripheral changes in T cells predict efficacy of anti-PD-1 immunotherapy in non-small cell lung cancer

The application of programmed cell death protein 1 (PD-1) antibodies has brought great benefits to non-small cell lung cancer (NSCLC) patients. Nevertheless, not all patients respond to anti-PD-1 immunotherapy. This study aimed to find response markers to predict efficacy of anti-PD-1 immunotherapy in NSCLC patients. 80 patients with NSCLC who would accept anti-PD-1 immunotherapy were recruited, and peripheral blood was obtained before and after treatment. Flow cytometry was used to detect proportions of circulating cell subsets and expression of co-stimulatory molecules, co-inhibitory molecules and cytokines in T cells from pre-and post-treatment patients. Results showed that proportions of CD4+ and CD8+ T cells, NK, gamma delta T and mucosal-associated invariant T (MAIT) cells were higher and regulatory T cells (Tregs) were lower in responders (n = 50) after treatment but no obvious difference was found in non-responders (n = 30). After treatment, responders showed an increase in the frequency of co-stimulatory and co-inhibitory molecules, as well as the production of cytokines in T cells. This study indicates that monitoring the alterations of immune markers in circulating cells from NSCLC patients may be helpful to discriminate responders and non-responders, which provides a potential novel way to assess efficacy of anti-PD-1 immunotherapy.