title: Ionizing radiation selectively reduces skin regulatory T cells and alters immune function.
abstract: The skin serves multiple functions that are critical for life. The protection from pathogens is achieved by a complicated interaction between aggressive effectors and controlling functions that limit damage. Inhomogeneous radiation with limited penetration is used in certain types of therapeutics and is experienced with exposure to solar particle events outside the protection of the Earth's magnetic field. This study explores the effect of ionizing radiation on skin immune function. We demonstrate that radiation, both homogeneous and inhomogeneous, induces inflammation with resultant specific loss of regulatory T cells from the skin. This results in a hyper-responsive state with increased delayed type hypersensitivity in vivo and CD4+ T cell proliferation in vitro. The effects of inhomogeneous radiation to the skin of astronauts or as part of a therapeutic approach could result in an unexpected enhancement in skin immune function. The effects of this need to be considered in the design of radiation therapy protocols and in the development of countermeasures for extended space travel.
authors: Division of Infectious Diseases, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors: Yu
authors: Y
authors: Zhou
authors: Division of Infectious Diseases, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors: Houping
authors: H
authors: Ni
authors: Division of Infectious Diseases, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors: Klara
authors: K
authors: Balint
authors: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors: Jenine K
authors: JK
authors: Sanzari
authors: Department of Dermatology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors: Tzvete
authors: T
authors: Dentchev
authors: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors: Eric S
authors: ES
authors: Diffenderfer
authors: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors: Jolaine M
authors: JM
authors: Wilson
authors: Department of Radiation Oncology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors: Keith A
authors: KA
authors: Cengel
authors: Division of Infectious Diseases, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors: Drew
authors: D
authors: Weissman
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000473:pathology; D049109:Cell Proliferation / Q000528:radiation effects; D005260:Female; D008297:Male; D008813:Mice, Inbred ICR; D011833:Radiation Injuries, Experimental / Q000276:immunology*; D011839:Radiation, Ionizing; D012867:Skin / Q000528:radiation effects*; D013552:Swine; D050378:T-Lymphocytes, Regulatory / Q000528:radiation effects*