title: Radiotherapy and immunotherapy: a beneficial liaison?
abstract: Investigations into the interaction between radiotherapy and the host immune system have uncovered new mechanisms that can potentially be exploited to improve the efficacy of radiotherapy. Radiation promotes the release of danger signals and chemokines that recruit inflammatory cells into the tumour microenvironment, including antigen-presenting cells that activate cytotoxic T-cell function. By contrast, radiation can attract immunosuppressive cells into the tumour microenvironment. In rare circumstances, the antitumour effect of radiotherapy has been observed outside of the radiation field, known as the abscopal effect. This phenomenon is proposed to have an immune origin and indicates that local radiotherapy elicits systemic effects. Herein, we highlight data that provide new mechanistic explanations for the success or failure of radiotherapy, and postulate how the combination of immune-modulation and radiation could tip the balance of the host immune response to promote cure. We use the concept of radiation- induced tumour equilibrium (RITE) as a starting point to discuss the mechanistic influence of immune-checkpoint therapies on radiotherapy efficacy.
authors.affiliation: Department of Radiation and Cellular Oncology and The Ludwig Center for Metastasis Research, The University of Chicago, 5758 South Maryland Avenue, BOX 9006, Chicago, Illinois 60637, USA.
authors.forename: Ralph R
authors.initials: RR
authors.lastname: Weichselbaum
authors.affiliation: Department of Radiation and Cellular Oncology and The Ludwig Center for Metastasis Research, The University of Chicago, 5758 South Maryland Avenue, BOX 9006, Chicago, Illinois 60637, USA.
authors.forename: Hua
authors.initials: H
authors.lastname: Liang
authors.affiliation: Department of Radiation and Cellular Oncology and The Ludwig Center for Metastasis Research, The University of Chicago, 5758 South Maryland Avenue, BOX 9006, Chicago, Illinois 60637, USA.
authors.forename: Liufu
authors.initials: L
authors.lastname: Deng
authors.affiliation: Department of Pathology, University of Texas Southwestern Medical Center, 6000 Harry Hines Boulevard, Dallas, Texas 75235-9072, USA.
authors.forename: Yang-Xin
authors.initials: YX
authors.lastname: Fu
mesh_terms: D056704:Adaptive Immunity / Q000528:radiation effects; D003131:Combined Modality Therapy; D006801:Humans; D007113:Immunity, Innate / Q000528:radiation effects; D007167:Immunotherapy; D009369:Neoplasms / Q000276:immunology / Q000532:radiotherapy / Q000628:therapy*; D059016:Tumor Microenvironment / Q000276:immunology / Q000528:radiation effects