Lung Transplantation

Lung transplantation is an increasingly viable therapeutic option for patients with end-stage pulmonary and pulmonary vascular disorders. Since the inception of the first lung transplant there has been substantial progress made in both the clinical and the basic science realms. More specifically, the lung transplant community has made advances in candidate selection via our ability to prognosticate outcomes of various lung diseases and through the implementation of the lung allocation scoring system. This system has resulted in decreased mortality for patients on the lung transplant waiting list. Additionally, we have identified risk factors for poor outcomes post–lung transplant with a better understanding of the physiological, cellular, and molecular mechanisms responsible for primary graft dysfunction (PGD), infectious diseases, acute rejection, antibody-mediated rejection, lymphocytic bronchiolitis, obliterative bronchiolitis, restrictive allograft syndrome, and chronic lung allograft dysfunction.

Although early post-survival has improved due to better surgical techniques and advances in critical care, severe PGD, infectious diseases (e.g., bacterial, viral, fungal, mycobacterial), and allograft rejection continue to be common causes of morbidity and mortality. Thus there is a need to extend our current understanding of how PGD, infection, and acute and chronic rejection interact leading to the demise of the lung allograft. This issue of Seminars in Respiratory and Critical Care Medicine is dedicated to lung transplantation and integrates both basic and clinical science, providing a comprehensive perspective on determining which patients need a lung transplant, how the lung allocation score impacts transplant recipients in the United States, factors contributing to PGD, the contribution of PGD to mortality, as well as long-term outcomes, diagnosis, and treatment of antibody-mediated rejection, acute cellular rejection, lymphocytic bronchitis, infectious diseases, and chronic lung allograft dysfunction.

Drs. McShane, Garrity, and associates review the role of the lung allocation scoring system and its impact on pre- and post–lung transplantation outcomes. Drs. Shah and Kotloff provide an overview of the prognosis of obstructive lung diseases and clinical criteria used for determining the most appropriate time to list these patients for a lung transplant. Dr. Gottlieb gives an overview of the physiological criteria used to select patients with pulmonary hypertension and idiopathic pulmonary fibrosis (IPF) to undergo lung transplantation as well as details regarding the role of single- versus double-lung transplantation for these patients. Dr. Corris provides the criteria being used for patients with cystic fibrosis and bronchiectasis to undergo lung transplantation.

Dr. Snell and associates give an overview on donor selection and the potential role of ex vivo lung perfusion strategies in improving the available numbers and quality of donated lungs. Dr. Suzuki and colleagues review the risk factors and pathophysiology of PGD, as well as the effects of PGD on long-term outcomes. Dr. Glanville adds insight into the role of bronchoscopy (surveillance and clinically indicated) and establishes the roles of acute cellular rejection and lymphocytic bronchiolitis in the development of BOS. Drs. Witt and Hachem discuss standard and novel immunosuppression regimens post–lung transplantation. Dr. Martinu and colleges review the biology, pathology, diagnostic criteria, and treatment options for acute allograft rejection and antibody-mediated rejection.

With augmentation of immunosuppressive medications there is increased risk of infections; Dr. Clark and associates discuss viral infections, whereas Dr. Bhaskaran targets fungal infections as causes of significant morbidity and mortality post–lung transplant. Dr. Verleden and associates discuss lung allograft dysfunction, different chronic allograft dysfunction phenotypes, and their effects on survival. Drs. Singer and Singer review quality of life of lung transplant recipients, and Dr. Weigt and associates give an overview of risk factors, pathogenesis, pathology, and treatment of BOS. Dr. Albores and colleagues discuss cases of recurrent disease in the allograft, focusing on alveolar proteinosis.

In addition to reviewing the progress made in the field of lung transplantation, this issue of Seminars in Respiratory and Critical Care Medicine highlights the areas where additional knowledge is required to improve the outcomes for lung transplant patients. Novel clinical and basic science studies will be required to advance the field in expanding the donor pool while reducing early allograft injury, choosing the right recipients for lung transplant, and understanding the clinical significance and biology of antibody-mediated rejection, and also to clarify the interactions of infection and rejection with the pathogenesis of chronic lung allograft dysfunction.

We would like to thank all the contributors for their hard work in preparing this issue of Seminars in Respiratory and Critical Care Medicine dedicated to lung transplantation, and we hope that it provides a comprehensive update for clinicians and researchers.