Review
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Transplant. May 29, 2020; 10(5): 104-116
Published online May 29, 2020. doi: 10.5500/wjt.v10.i5.104
Chronic lung allograft dysfunction post-lung transplantation: The era of bronchiolitis obliterans syndrome and restrictive allograft syndrome
Nobuyuki Yoshiyasu, Masaaki Sato
Nobuyuki Yoshiyasu, Masaaki Sato, Department of Thoracic Surgery, The University of Tokyo Hospital, Tokyo 113-8655, Japan
Author contributions: Yoshiyasu N and Sato M equally contributed to this paper in the conception and design of the study, literature review and analysis, drafting and critical revision and editing, and final approval of the final version.
Conflict-of-interest statement: Authors declare no conflict of interests for this article.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (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/
Corresponding author: Masaaki Sato, MD, PhD, Director, Department of Thoracic Surgery, The University of Tokyo Hospital, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan. satom-sur@h.u-tokyo.ac.jp
Received: February 24, 2020
Peer-review started: February 24, 2020
First decision: April 25, 2020
Revised: April 30, 2020
Accepted: May 12, 2020
Article in press: May 12, 2020
Published online: May 29, 2020
Abstract

Chronic lung allograft dysfunction (CLAD) following lung transplantation limits long-term survival considerably. The main reason for this is a lack of knowledge regarding the pathological condition and the establishment of treatment. The consensus statement from the International Society for Heart and Lung Transplantation on CLAD in 2019 classified CLAD into two main phenotypes: Bronchiolitis obliterans syndrome and restrictive allograft syndrome. Along with this clear classification, further exploration of the mechanisms and the development of appropriate prevention and treatment strategies for each phenotype are desired. In this review, we summarize the new definition of CLAD and update and summarize the existing knowledge on the underlying mechanisms of bronchiolitis obliterans syndrome and restrictive allograft syndrome, which have been elucidated from clinicopathological observations and animal experiments worldwide.

Keywords: Lung transplantation, Chronic lung allograft dysfunction, Bronchiolitis obliterans syndrome, Restrictive allograft syndrome, Interaction of immune cells, Anatomical changes in transplanted lungs

Core tip: Long-term prognosis following lung transplantation has not improved due to chronic lung allograft dysfunction (CLAD). Although a decade has passed since restrictive allograft syndrome with poor outcome was proposed, which was subsequently included as a new CLAD phenotype in the consensus report from International Society for Heart and Lung Transplantation in 2019, detailed mechanisms involved remain largely unknown. Here, we discuss the mechanisms of CLAD from an immunological point of view.