Single-cell Profiling of Immune cells After Neoadjuvant Pembrolizumab and Chemotherapy in ⅢA non-small cell lung cancer (NSCLC)

Abstract The combination of immune checkpoint inhibitors (ICIs) with chemotherapy (chemoimmunotherapy) in the neoadjuvant setting have achieved favorable clinical benefits in non-small cell lung cancer (NSCLC), but the mechanism of clinical responses remain unclear. To identify factors associated with the clinical outcome, we provide a rich resource of 186,477 individual immune cells from matched multiple immune-relevant tissue sites and peripheral blood of four treatment-naïve and eight neoadjuvant chemoimmunotherapy treated ⅢA NSCLC patients (responders versus non-responders) by single-cell RNA-seq and TCR-seq. We showed that the synergistic increase of B cells and CD4+ T cells are associated with positive therapeutic response of neoadjuvant chemoimmunotherapy. B cell IgG subclasses IgG1 and IgG3 play a critical role in anti-tumor immune response in tumor lesion, and this process was driven by increased IL-21 protein secreted by infiltrated T follicular helper (Tfh) cells after neoadjuvant chemoimmunotherapy. Furthermore, we uncovered several critical events for positive clinical outcome, including the diminished activated TNFRSF4+ regulatory T cells (Tregs), increased LAMP3+ dendritic cells (DCs), high pre-therapy peripheral blood T-cell diversity, and the expansion of intratumoral CD4+ T clones and peripheral CD8+ T clones. In total, our comprehensive study of the single-cell profile of immune cells provide mechanistic insight of clinical responses and identified novel predictive factors and potential therapeutic targets for improving the efficiency of neoadjuvant chemoimmunotherapy in NSCLC.