Longitudinal peripheral immune dynamics during anti-programmed cell death 1 neoadjuvant therapy in esophageal squamous cell carcinoma

Abstract

Introduction Anti-programmed cell death 1 (PD-1)-based neoadjuvant therapy is increasingly used for esophageal squamous cell carcinoma (ESCC), but paired peripheral immune dynamics and their exploratory relationship to response remain incompletely characterized. Methods We performed a retrospective longitudinal flow-cytometry study of 39 patients with ESCC treated with anti-PD-1-based neoadjuvant therapy, including 20 patients with paired pre-treatment and post-treatment/preoperative peripheral immune profiles. The primary paired analysis tested 75 marker-defined immune features using Wilcoxon signed-rank tests with Benjamini-Hochberg false discovery rate (FDR) correction. Exploratory extensions included response-associated changes in candidate immune features, clinical burden context, baseline-dependence, and public tissue-context bioinformatics. Public tissue data were used only as descriptive tissue context. Results Four features reached FDR q<0.05 in the primary paired screen: PD-1+ CD8 T cells, PD-1+ Vδ1 γδ T cells, PD-1+ Vδ2 γδ T cells, and CD19+ B cells. PD-1-defined features were interpreted as assay-defined detectable PD-1 staining readouts because therapeutic anti-PD-1 receptor occupancy or epitope masking may affect post-treatment staining. CD19+ B cells remained the non-PD-1 q<0.05 anchor in the PD-1-excluded paired sensitivity screen. In the pathology-evaluable paired cohort (n=17), no response-stratified candidate reached q<0.05; the change in NKG2D+ natural killer (NK) cells was the strongest nominal exploratory and hypothesis-generating signal. Discussion These data support treatment-associated marker-defined peripheral immune dynamics and generate response-linked hypotheses requiring prospective validation.