Metal–Allergy Cross-Reactions in Mice

Few adequate animal models exist for metal-allergies. However, we previously found that lipopolysaccharide (LPS) promote metal-allergies in mice, and we thereby established a reproducible murine metal-allergy model. Information concerning cross-reactivity among metals is still insufficient, especially lacking the studies in vivo. Here, we used this murine model to examine allergic cross-reactions among some metals. In the experiments using ultra-pure metals (Ni, Pd, Co, Cr, and Cu), Ni and Pd cross-reacted, and their minimum allergy-inducing concentrations were similar. However, there were no cross-reactions among other tested metals. Surprisingly, in the experiments using low-purity metals, all the tested metals (Ni, Pd, Co, Cr, and Cu) cross-reacted. Our findings suggest that there is cross-reactivity between Ni and Pd in the tested metal (Ni, Pd, Co, Cr, and Cu) and high-purity metal salts should be considered for use in clinical patch-testing.