The circulating pool of functionally competent NK and CD8+ cells predicts the outcome of anti-PD1 treatment in advanced NSCLC

Abstract

IntroductionA prospective investigation of the circulating immune profile in NSCLC patients receiving nivolumab was performed to identify potentially predictive parameters. MethodsFlow Cytometry of peripheral blood (PB) CD3+, CD8+, CD4+, NK, Treg and MDSCs was prospectively performed in 31 consecutive advanced NSCLC patients at baseline (T0) and after 2 (T1) and 4 (T2) cycles of bi-weekly nivolumab. Functional molecules (PD-1, CD3ζ, Granzyme B, Perforin), cell proliferation (Ki67) and NK receptors (NKG2 A, NKG2D, NKp30) were also explored. The immunohistochemical evaluation of PD-L1 and TILs was restricted to available tumor biopsies. Tissue and circulating parameters were correlated to clinico-pathological features and treatment outcomes. ResultsKRAS mutations, active smoking, COPD and steroid treatment conditioned a different distribution of circulating phenotypes. At baseline, clinical benefit (CB, n = 19) group displayed higher number of phenotypically active NK and PD-1+CD8+ cells (p < 0.01) compared to non-responders (NR, n = 12). Prolonged survival outcomes (p < 0.01) were recorded in cases with high baseline circulating NK and PD-1+CD8+ cells. At tissue level, low PD-1 expression in CD8 + TILs was a positive prognostic feature (p < 0.001). Strikingly, high circulating NK and PD-1+CD8+ cells combined with low PD-1/CD8+ ratio in TILs characterized a privileged context able to provide a significantly prolonged (p < 0.01) progression-free survival (PFS). During PD-1 blockade, NKs progressively raised in CB while declined in NR (p < 0.05) and this phenomenon was counterbalanced by parallel changes in Treg. ConclusionThe functional pool of circulating NKs associated with a divergent PD-1 expression in blood and tissue CD8+ lymphocytes portrays an immune profile predictive of anti-PD1 treatment efficacy.