Stage-dependent spatial distribution and prognostic value of CD8+ tissue-resident memory T cells in NSCLC

CD8⁺ tissue-resident memory T cells (CD8⁺T_RM), expressing PD-1 and/or TIM-3, are linked to immunological surveillance in non-small cell lung cancer (NSCLC). However, their prognostic value across activation states and spatial distributions in NSCLC stages is unclear. We analyzed 271 NSCLC patients' primary tumors and lymph nodes, using multiplex immunohistochemistry and inForm software for cell identification. Statistical analyses included the Mann-Whitney U test and Cox survival analysis. Findings showed CD8⁺T_RM were categorized into four activation states. In locally advanced NSCLC, PD-1^-TIM-3⁺CD8⁺T_RM3, and PD-1⁺TIM-3⁺CD8⁺T_RM4 densities were notably higher at invasive margins. Fewer interactions between CD8⁺T_RM and tumor cells were observed in advanced lesions. Decreased PD-1⁺TIM-3^-CD8⁺T_RM2 interactions with tumor cells and increased PD-1⁺TIM-3⁺CD8⁺T_RM4 interactions with tumor cells were independently associated with recurrence in patients with early lung adenocarcinoma and squamous carcinoma, respectively. These results suggest that CD8⁺T_RM activation state and distribution are linked to recurrence risk in early-stage NSCLC, emphasizing the importance of CD8⁺T_RM spatial dynamics in prognosis.