[Frontiers in Bioscience E1, 36-43, June 1, 2009]

Toll-like receptors (TLRs) in transplantation

Maria-Luisa Alegre1, Anita Chong2

1Departments of Medicine, The University of Chicago, 5841 S. Maryland Avenue, Chicago, IL60637, USA, 2Department of Surgery, 5841 S. Maryland Avenue, Chicago, IL60637, USA


1. Abstract
2. Introduction
3. TLRs in transplantation
3.1 .Role of TLRs in IRI
3.2. Function of TLRs in acute rejection of solid organ allografts
3.3. Role of TLRs in GVHD
3.4. TLRs in acute xenograft rejection
3.5. Role of TLRs in chronic allograft rejection
3.6. Effects of TLR signals in transplantation tolerance
3.7. Human TLR expression and polymorphisms in transplantation 4. Summary and perspective
5. Acknowledgements
6. References


TLRs have been extensively studied over the past decade for their ability to recognize microbial molecular patterns and activate innate immune cells to fight infections. They have also been described to provide a link between innate and adaptive immunity, as TLR signals also enhance the antigen presenting capacity of innate immune cells to T cells. In recent years, a contribution of TLR pathways to immune responses elicited by ischemia/reperfusion injury (IRI), allografts and xenografts has been uncovered, although the ligands that bind TLRs in these settings remain to be revealed. Such research has the potential to identify novel therapeutic targets that may facilitate allograft acceptance. In this review, we will summarize the results published to date on the role of TLRs in experimental and clinical transplantation.