Immunosuppression in lung transplantation: a narrative review

Background and Objective: Lung transplantation has grown as a treatment option for patients with end stage lung disease. Unfortunately, median survival for lung transplant recipients remains low at 6.7 years. Acute rejection and chronic lung allograft dysfunction (CLAD) are among the main challenges to graft function and overall survival. Immunosuppression is utilized to reduce the rate of rejection, and can be utilized as a treatment for acute rejection and CLAD. The purpose of this review is to describe the immunosuppressive agents used in lung transplantation for induction therapy, maintenance therapy, and prevention of both acute and chronic allograft rejection. Methods: PubMed was searched using keywords including "lung transplantation, immunosuppression, induction, maintenance" from January 1985 to June 2022. Systematic reviews, randomized clinical trials, retrospective and cross-sectional studies, case series, and some animal studies were considered for inclusion in this review, with no language restrictions. Key Content and Findings: Immunosuppressive strategies may begin with induction therapy, which typically includes agents such as basiliximab, anti-thymocyte globulin (ATG), or alemtuzumab, in addition to high dose corticosteroids. Maintenance immunosuppression typically consists of a calcineurin inhibitor (CNI), antiproliferative agent, and corticosteroids. Numerous adjunctive agents have been evaluated for prevention and treatment of rejection, particularly CLAD, though robust data supporting use of these agents is limited. Conclusions: Immunosuppression in lung transplantation remains crucial for prevention and treatment of acute and chronic rejection, which continue to represent significant sources of morbidity and mortality in this population. Induction and maintenance immunosuppression strategies vary across lung transplantation centers. Additional research is needed to better define the optimal strategies and choices of agents for immune suppression following lung transplantation.