Abstract 7633: CXCR6 positive circulating mucosal-associated invariant T cells play the anti-tumor effect in non-small cell lung caner immunotherapy

Abstract Background: Mucosal-associated invariant T (MAIT) cells is are unconventional innate-like T lymphocytes abundant in human tissues. Recent studies have shown that MAIT cells play important roles in regulating tumor immunity. However, the immune characteristics of MAIT cells in non-small cell lung cancer (NSCLC) and its correlation with ICIs treatment efficacy remain unclear. Method: In this study, we used single-cell RNA-sequencing (scRNA-seq), flow cytometry and multiplex immunofluorescence to assess the proportion and characteristics of CD8+MAIT cells in metastatic NSCLC patients who respond or not respond to anti-PD-1 therapy. Results: The proportions of activated and proliferating CD8+ T cells and MAIT cells were significantly higher in responders-derived PBMC or lung tissues prior to anti-PD-1 therapy. Both peripheral and tumor-infiltrating CD8MAIT cells displayed upregulated CXCR6 (P0. 05). Besides, CXCR6+CD8MAIT cells from responders had higher expression of cytotoxicity-related genes, like CST7, GNLY, KLRG1, NKG7 and PRF1. Moreover, we found that patients with 1. 7% of MAIT among peripheral CD8+ population showed a better response to immunotherapy. Conclusion: CD8MAIT cells may be considered a predictive biomarker for patients responding to anti-PD-1 therapy in NSCLC. The correlation between CD8MAIT and immunotherapy sensitivity may ascribe to high expression of CXCR6. Citation Format: Jingjing Qu, Binggen Wu, Yuekang Li, Qian Shen, Wenjia Sun, Lijun Chen, Jianya Zhou, Jianying Zhou. CXCR6 positive circulating mucosal-associated invariant T cells play the anti-tumor effect in non-small cell lung caner immunotherapy abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 7633.