title: Killer Ig-like receptor-mediated control of natural killer cell alloreactivity in haploidentical hematopoietic stem cell transplantation.
abstract: Natural killer (NK) cells are key members of the innate immune system. In a self-environment, they sense and kill target cells lacking major histocompatibility complex class I molecules and release various cytokines on activation. The discovery of human leukocyte antigen (HLA) class I specific inhibitory receptors (including the allotype-specific killer immunoglobulin-like receptors), and of various activating receptors and their ligands, provided the basis for understanding the molecular mechanism of NK-cell activation and function, mainly resulting from the balance between activating and inhibitory signals. In an allogeneic setting, such as T cell-depleted haploidentical hematopoietic stem cell transplantation, NK cells may express inhibitory killer immunoglobulin-like receptors that are not engaged by any of the HLA class I alleles present on allogeneic cells. Such "alloreactive" NK cells greatly contribute both to eradication of leukemia blasts escaping the preparative regimen and to clearance of residual host dendritic cells and T lymphocytes (thus preventing graft-versus-host disease and graft rejection, respectively). Improved prevention of graft-versus-host disease might be achieved by redirecting to lymph nodes adoptively transferred, alloreactive NK cells by inducing CCR7-uptake in vitro. Recent studies suggested that, after immune-suppressive therapy, alloreactive NK cells from an HLA-haploidentical donor may prevent leukemia recurrence also in patients who have not received allogeneic hematopoietic stem cell transplantation.
authors.affiliation: Giannina Gaslini Institute, Genova-Quarto, Italy. lorenzomoretta@ospedale-gaslini.ge.it
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Moretta
authors.forename: Franco
authors.initials: F
authors.lastname: Locatelli
authors.forename: Daniela
authors.initials: D
authors.lastname: Pende
authors.forename: Emanuela
authors.initials: E
authors.lastname: Marcenaro
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Mingari
authors.forename: Alessandro
authors.initials: A
authors.lastname: Moretta
mesh_terms: D006084:Graft Rejection / Q000276:immunology; D006086:Graft vs Host Disease / Q000276:immunology; D006680:HLA Antigens / Q000276:immunology / Q000378:metabolism; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism; D018448:Models, Immunological; D054400:Receptors, CCR7 / Q000276:immunology / Q000378:metabolism; D054340:Receptors, KIR / Q000276:immunology* / Q000378:metabolism
chemical_list: D006680:HLA Antigens; D054400:Receptors, CCR7; D054340:Receptors, KIR