Abstract
Allograft rejection continues to be a significant obstacle in the field of organ transplantation. There is a significant body of evidence demonstrating that endothelial cells in the allograft are in many cases the targets of acute and chronic rejection1-3. Such a concept is intuitive as these are the first cells that come into contact with recipient lymphocytes and antigen-presenting cells (APCs). A growing body of evidence indicates that epithelial cells may also be immunologic targets in the process of lung, liver, and kidney allograft rejection¢$. The immunobiology of epithelial cells as related to the field of organ transplantation has been best characterized in the process of lung allograft rejection and, therefore, this chapter will focus on the role of airway epithelial cells (AECs) and their significance in lung allograft rejection.