title: NK cells after transplantation: friend or foe.
abstract: Natural killer (NK) cells are effector cells of the innate immune system that can lyse target cells without prior sensitization and have an important role in host defense to pathogens and transformed cells. A balance between negative and positive signals transmitted via germ line-encoded inhibitory and activating receptors controls the function of NK cells. Although the concept of "missing-self" would suggest that NK cells could target foreign allografts, the prevailing dogma has been that NK cells are not active participants in the mechanisms that culminate in the rejection of solid organ allografts. Recent studies, however, challenge this conclusion and instead implicate NK cells in contributing to both graft rejection and tolerance to an allograft. In this review, we highlight recent studies with the goal of understanding the complex NK cell interactions that impact alloimmunity.
authors: Division of Abdominal Transplantation, Department of Surgery and Stanford Immunology, Stanford University School of Medicine, Stanford, CA, USA.
authors: Uzi
authors: U
authors: Hadad
authors: Olivia
authors: O
authors: Martinez
authors: Sheri M
authors: SM
authors: Krams
mesh_terms: D000818:Animals; D002450:Cell Communication / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology / Q000378:metabolism; D006084:Graft Rejection / Q000276:immunology; D006801:Humans; D054992:Immunological Synapses / Q000276:immunology / Q000378:metabolism; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism; D010641:Phenotype; D014180:Transplantation; D014181:Transplantation Immunology; D023001:Transplantation Tolerance / Q000276:immunology; D014184:Transplantation, Homologous