放射治疗是一种既定且有效的抗癌治疗方式。广泛的临床前实验表明，放疗的促炎特性可能与检查点免疫疗法具有协同作用。辐射会引起双链 DNA 断裂 (dsDNA)。 dsDNA 的感应会激活 cGAS/STING 通路，产生招募抗原呈递细胞 (APC) 所必需的 1 型干扰素。辐射通过释放通过调查抗原呈递细胞捕获和交叉呈递的肿瘤相关抗原来促进细胞毒性 CD8 T 细胞的募集。辐射诱导的血管正常化可能进一步促进 T 细胞运输和药物输送。放射线也具有免疫抑制作用。调节性 T 细胞 (Treg) 和骨髓源性抑制细胞 (m-MDSC) 等先天细胞的募集都会抵消辐射的免疫刺激特性。许多先天免疫细胞类型在适应性免疫反应的界面上发挥作用。 m-MDSC等先天免疫细胞可以通过表达PD-L1等免疫检查点来发挥其免疫抑制作用，这进一步凸显了联合放疗和检查点免疫治疗的潜力。几项调查放射治疗和免疫治疗结合的早期临床研究令人失望。更好地了解放射治疗对先天免疫系统的影响对于优化放射免疫治疗组合至关重要。本综述将总结放疗对先天免疫系统关键细胞和重要免疫抑制细胞因子的影响。版权所有 © 2023。由 Elsevier Inc. 出版。

Radiation therapy is an established and effective anti-cancer treatment modality. Extensive pre-clinical experimentation has demonstrated that the pro-inflammatory properties of irradiation may be synergistic with checkpoint immunotherapy. Radiation induces double-stranded DNA breaks (dsDNA). Sensing of the dsDNA activates the cGAS/STING pathway, producing Type 1 interferons essential to recruiting antigen-presenting cells (APCs). Radiation promotes cytotoxic CD8 T-cell recruitment by releasing tumour-associated antigens captured and cross-presented by surveying antigen-presenting cells. Radiation-induced vascular normalisation may further promote T-cell trafficking and drug delivery. Radiation is also immunosuppressive. Recruitment of regulatory T cells (Tregs) and innate cells such as myeloid-derived suppressive cells (m-MDSCs) all counteract the immunostimulatory properties of radiation. Many innate immune cell types operate at the interface of the adaptive immune response. Innate immune cells, such as m-MDSCs, can exert their immunosuppressive effects by expressing immune checkpoints such as PD-L1, further highlighting the potential of combined radiation and checkpoint immunotherapy. Several early-phase clinical studies investigating the combination of radiation and immunotherapy have been disappointing. A greater appreciation of radiotherapy's impact on the innate immune system is essential to optimise radioimmunotherapy combinations. This review will summarise the impact of radiotherapy on crucial cells of the innate immune system and vital immunosuppressive cytokines.Copyright © 2023. Published by Elsevier Inc.