Cross-Reactivity of Intraoral Allergic Contact Mucositis in the Nickel-Sensitized Ear Model of Metal Allergy.

Cross-reactivity of metal allergies can make metal allergy treatment complicated because the background of immune response in cross-reactions remains unknown. In clinical settings, cross-reactivity among several metals has been suspected. However, the precise mechanism of immune response in cross-reactivity is unclear. Two sensitizations with nickel, palladium, and chromium plus lipopolysaccharide solution into the postauricular skin were followed by a single nickel, palladium, and chromium challenge of the oral mucosa to generate the intraoral metal contact allergy mouse model. Results showed that the infiltrating T cells in nickel-sensitized, palladium- or chromium-challenged mice expressed CD8+ cells, cytotoxic granules, and inflammation-related cytokines. Thus, nickel ear sensitization can cause cross-reactive intraoral metal allergy.

Cross-Reactivity of Palladium in a Murine Model of Metal-Induced Allergic Contact Dermatitis.

Metal allergy is usually diagnosed by patch testing, however, the results do not necessarily reflect the clinical symptoms because of cross-reactivity between different metals. In this study, we established the novel mouse model of cross-reactive metal allergy, and aimed to elucidate the immune response in terms of T-cell receptor repertoire. This model was classified into two groups: the sensitization to nickel and challenge with palladium group, and the sensitization to chromium and challenge with palladium group. This model developed spongiotic edema with intra- and peri-epithelial infiltration of CD4+ T cells in the inflamed skin that resembles human contact dermatitis. Using T cell receptor analysis, we detected a high proportion of T cells bearing Trav8d-1-Traj49 and Trav5-1-Traj37 in the Ni- and Cr-sensitized Pd-challenged mice. Furthermore, mucosal-associated invariant T cells and invariant natural killer T cells were also detected. Our results indicated that T cells bearing Trav8d-1-Traj49 and Trav5-1-Traj37 induced the development of palladium-cross reactive allergy, and that mucosal-associated invariant T and invariant natural killer T cells were also involved in the cross-reactivity between different metals.