The Single Cell Immunogenomic Landscape after Neoadjuvant Immunotherapy combined Chemotherapy in Esophageal Squamous Cell Carcinoma

Neoadjuvant immunotherapy represents promising strategy in the treatment of esophageal squamous cell carcinoma (ESCC). However, the mechanisms underlying its impact on treatment sensitivity or resistance remain a subject of controversy. In this study, we conducted single-cell RNA and T/B cell receptor (scTCR/scBCR) sequencing of CD45+ immune cells on samples from 10 patients who received neoadjuvant immunotherapy and chemotherapy. We also validated our findings using multiplexed immunofluorescence and analyzed bulk RNA-seq from other cohorts in public database. By integrating analysis of 87357 CD45+ cells, we found GZMK+ effector memory T cells were relatively enriched and CXCL13+ exhausted T cells and regulator T cells decreased among responders, indicating a persistent anti-tumor memory process. Additionally, the enhanced presence of BCR expansion and somatic hypermutation process within TNFRSF13B+ memory B cells suggested their roles in antigen presentation. This was further corroborated by the evidence of the T-B co-stimulation pattern and CXCL13-CXCR5 axis. The complexity of myeloid cell heterogeneity was also particularly pronounced. The elevated expression of S100A7 in ESCC, as detected by bulk RNA-seq, was associated with an exhausted and immunosuppressive tumor microenvironment. In summary, this study has unveiled a potential regulatory network among immune cells and the clonal dynamics of their functions, and the mechanisms of exhaustion and memory conversion between GZMK+ Tem and TNFRSF13B+ Bmem from antigen presentation and co-stimulation perspectives during neoadjuvant PD-1 blockade treatment in ESCC.