title: CD56highCD16-CD62L- NK cells accumulate in allergic contact dermatitis and contribute to the expression of allergic responses.
abstract: Allergic contact dermatitis is a common disease caused by an exaggerated T cell-mediated immune response to skin-applied haptens. We show in this study that NK cells affect skin immune responses to haptens by releasing type 1 cytokines and inducing keratinocytes apoptosis. Immunohistochemical stainings demonstrated that NK lymphocytes constitute approximately 10% of the inflammatory infiltrate mostly distributed in the superficial dermis and in the epidermis at the site of intense spongiotic changes. More than 90% of NK cells isolated from allergic contact dermatitis skin showed a CD3-CD56(high)CD16- phenotype by FACS analysis. In addition, they uniformly expressed NKG2A, intermediate to high levels of perforin, and the activating receptors, NKG2D, NKp44, and NKp46, but lacked NKp30 and killer Ig-related receptors. Skin NK lymphocytes displayed a CXCR3+CCR6+CCR5+ chemokine receptor asset for homing into inflamed skin, but not CD62L and CCR7 for lymph node homing. When NK cells from nickel-allergic donors were exposed in vitro to the metal, they failed to proliferate, to upregulate CD69, and to release IFN-gamma, thus indicating that NK lymphocytes do not exhibit memory-like properties to haptens. However, IL-2 released by hapten-driven T lymphocytes rapidly induced the release of IFN-gamma by NK cells and promoted the NK-mediated apoptosis of autologous keratinocytes in a hapten-independent manner. Our findings underline the importance of the interaction between innate and adaptive immune mechanisms for amplification of skin allergic responses to haptens and full expression of allergic contact dermatitis.
authors.affiliation: Laboratory of Immunology, Istituto Dermopatico dell'Immacolata-Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy.
authors.forename: Teresa
authors.initials: T
authors.lastname: Carbone
authors.forename: Francesca
authors.initials: F
authors.lastname: Nasorri
authors.forename: Davide
authors.initials: D
authors.lastname: Pennino
authors.forename: Kilian
authors.initials: K
authors.lastname: Eyerich
authors.forename: Stefanie
authors.initials: S
authors.lastname: Foerster
authors.forename: Loredana
authors.initials: L
authors.lastname: Cifaldi
authors.forename: Claudia
authors.initials: C
authors.lastname: Traidl-Hoffman
authors.forename: Heidrun
authors.initials: H
authors.lastname: Behrendt
authors.forename: Andrea
authors.initials: A
authors.lastname: Cavani
mesh_terms: D056704:Adaptive Immunity; D017209:Apoptosis; D019002:CD56 Antigen; D002633:Chemotaxis; D016207:Cytokines / Q000378:metabolism; D017449:Dermatitis, Allergic Contact / Q000276:immunology* / Q000473:pathology; D006241:Haptens / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate; D015603:Keratinocytes / Q000473:pathology; D007694:Killer Cells, Natural / Q000276:immunology* / Q000473:pathology; D019041:L-Selectin; D019707:Receptors, Chemokine; D017452:Receptors, IgG
chemical_list: D019002:CD56 Antigen; D016207:Cytokines; D006241:Haptens; D019707:Receptors, Chemokine; D017452:Receptors, IgG; D019041:L-Selectin