Roles of Toll-like receptors in transplantation

Beyond their crucial role in host defence against invading pathogens, Toll-like receptors (TLRs) are now known to be key mediators of the 'sterile' innate immune response triggered by tissue injury. Here, we will review recent evidence examining the role of TLRs in determining the fate of the transplanted organ.

Experimental studies have delineated a crucial role for TLRs in the pathogenesis of ischaemia-reperfusion injury (IRI). Following transplantation, experimental models and observational human studies have confirmed TLRs as mediators of IRI but also suggest that TLRs modify the subsequent adaptive alloimmune response, which determines whether an organ is rejected or accepted.

As a key determinant of organ damage following ischaemia-reperfusion and as a modulator of the adaptive alloimmune response, we propose that TLR-mediated innate immune responses represent a potential therapeutic target to improve organ outcomes following transplantation.