Stereotactic Ablative Radiation Therapy Induces Systemic Differences in Peripheral Blood Immunophenotype Dependent on Irradiated Site

Our data suggest SAR to parenchymal sites induces systemic immune changes, including a decrease in total and cytotoxic NK cells, an increase in TIM3+ NK cells, and an increase in activated memory CD4+ and CD8+ T cells. SAR to nonparenchymal sites did not induce these changes. By comparing the immune response after radiation to different organs, our data suggest SAR induces systemic immunologic changes that are dependent on the irradiated site.