Minireviews
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Transplant. Mar 24, 2015; 5(1): 11-18
Published online Mar 24, 2015. doi: 10.5500/wjt.v5.i1.11
Ultraviolet-induced alloantigen-specific immunosuppression in transplant immunity
Tomohide Hori, Kagemasa Kuribayashi, Kanako Saito, Linan Wang, Mie Torii, Shinji Uemoto, Taku Iida, Shintaro Yagi, Takuma Kato
Tomohide Hori, Shinji Uemoto, Taku Iida, Shintaro Yagi, Department of Hepato-Pancreato-Biliary and Transplant Surgery, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
Kagemasa Kuribayashi, Linan Wang, Mie Torii, Takuma Kato, Department of Cellular and Molecular Immunology, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
Kanako Saito, Department of Hematology and Medical Oncology, Mie University Graduate School of Medicine, Tsu 514-8507, Japan
Author contributions: Hori T, Saito K, Wang L and Torii M collected previous reports and helped to review these papers; Iida T and Yagi S helped to collect important papers; Hori T wrote this review paper; Kuribayashi K, Uemoto S and Kato T supervised this review.
Conflict-of-interest: The authors have no financial conflicts of interest to declare.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Tomohide Hori, MD, PhD, Department of Hepato-Pancreato-Biliary and Transplant Surgery, Kyoto University Graduate School of Medicine, 54 Shogoinkawara-cho, Sakyo-ku, Kyoto 606-8507, Japan. horit@kuhp.kyoto-u.ac.jp
Telephone: +81-75-7513651 Fax: +81-75-7513106
Received: July 17, 2014
Peer-review started: July 18, 2014
First decision: October 28, 2014
Revised: November 2, 2014
Accepted: January 15, 2015
Article in press: January 19, 2015
Published online: March 24, 2015
Abstract

After the first observation of the immunosuppressive effects of ultraviolet (UV) irradiation was reported in 1974, therapeutic modification of immune responses by UV irradiation began to be investigated in the context immunization. UV-induced immunosuppression is via the action of regulatory T cells (Tregs). Antigen-specific Tregs were induced by high-dose UV-B irradiation before antigen immunization in many studies, as it was considered that functional alteration and/or modulation of antigen-presenting cells by UV irradiation was required for the induction of antigen-specific immunosuppression. However, it is also reported that UV irradiation after immunization induces antigen-specific Tregs. UV-induced Tregs are also dominantly transferable, with interleukin-10 being important for UV-induced immunosuppression. Currently, various possible mechanisms involving Treg phenotype and cytokine profile have been suggested. UV irradiation accompanied by alloantigen immunization induces alloantigen-specific transferable Tregs, which have potential therapeutic applications in the transplantation field. Here we review the current status of UV-induced antigen-specific immunosuppression on the 40th anniversary of its discovery.

Keywords: Alloantigen, Ultraviolet irradiation, Donor-specific immunosuppression, Interleukin-10, Regulatory T cells

Core tip: The perception of immunological changes induced by ultraviolet (UV) exposure has changed over the past several years. Although carcinogenesis and immunosuppression due to UV irradiation are regarded as detrimental, UV irradiation is also currently considered a useful tool to induce alloantigen-specific regulatory T cells (Tregs). There is great enthusiasm for the potential to develop strategies that can use Tregs for therapeutic interventions. Alloantigen-specific immunosuppression is an ideal therapy for allotransplant recipients. Although the full mechanism has yet to be determined, UV irradiation accompanied by alloantigen immunization produces a beneficial effect in transplant immunity via the induction of alloantigen-specific transferable Tregs.