Do NK-cell receptors and alloreactivity affect solid organ transplantation?
Although natural killer cells lyse targets without pre-sensitization, and in an MHC-unrestricted manner, they can also respond to healthy allogeneic cells of different MHC type. Such alloreactivity is a consequence of NK cells using clonally distributed, inhibitory MHC class I receptors to achieve tolerance to healthy autologous cells. Absence of an appropriate MHC class I ligand on an allogeneic cell erroneously informs the NK cell that the allogeneic cell has lost MHC class I expression and should be killed. Potential NK-cell allo-reactivities are common in non-HLA-identical hematopoietic cell transplants and can have both beneficial and detrimental effects. Less is known of NK-cell allo-reactivities in solid organ transplantation. In animal models NK cells are neither necessary nor sufficient for acute transplant rejection, but they can make a contribution by helping activate T cells. Genes encoding NK-cell receptors for polymorphic MHC class I molecules are also highly polymorphic, contributing to variability of the NK-cell repertoire and response in the human population. These receptors could represent intrinsic patient factors that influence the success of their transplanted solid organs.
Vilches
Carlos
C
Servicio de Inmunología, Hospital Universitario Puerta de Hierro, San Martín de Porres 4, 28035 Madrid, Spain. carlos.vilches@yahoo.com
Parham
Peter
P
D000818:Animals; D016026:Bone Marrow Transplantation / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000378:metabolism; D006801:Humans; D007519:Isoantigens; D007694:Killer Cells, Natural / Q000276:immunology*; D008024:Ligands; D051379:Mice; D018448:Models, Immunological; D011971:Receptors, Immunologic / Q000378:metabolism*; D017634:Self Tolerance; D014181:Transplantation Immunology
D015395:Histocompatibility Antigens Class I; D007519:Isoantigens; D008024:Ligands; D011971:Receptors, Immunologic