Toll-like receptors and graft rejection.

Innate immunity plays a role in fighting against invading microorganisms. Emerging evidence suggests that in addition to responding to pathogen-associated molecular patterns of microorganisms, Toll-like receptors (TLRs) can be activated by endogenous ligands expressed by mammalian cells. Clinical and laboratory studies have shown that TLRs may participate in organ graft rejection and transplant immune tolerance, which are briefly reviewed in the present manuscript.