Distinct Skin Penetration and Immune Responses to Ionic and Nanoparticulate Cobalt in Allergic Contact Dermatitis.
Ionic and nanoparticulate cobalt trigger distinct skin gene-expression programs in allergy
Distinct Skin Penetration and Immune Responses to Ionic and Nanoparticulate Cobalt in Allergic Contact Dermatitis.
Cobalt is a well-established cause of allergic contact dermatitis (allergic contact dermatitis), but data on the skin absorption, toxicity, and immunological effects of cobalt nanoparticles (cobalt nanoparticles) remain limited.
Fourteen cobalt-allergic individuals underwent standardized patch testing with cobalt chloride (CoCl 2 ) and cobalt nanoparticles at equivalent nominal doses.
Both CoCl 2 and cobalt nanoparticles elicited positive patch test reactions, although cobalt nanoparticles responses were delayed and milder.
Lipid metabolic pathways were significantly associated with reaction strength in CoCl 2 -exposed skin but not in cobalt nanoparticles-exposed samples.
Functional enrichment of these genes revealed distinct biological signatures between exposures, including upregulated interferon and antiviral pathways and downregulated epithelial differentiation programs in CoCl 2 compared to cobalt nanoparticles.
Cobalt-induced allergic contact dermatitis is shaped by both reaction strength and cobalt speciation.
While CoCl 2 and cobalt nanoparticles share a core interferon-driven inflammatory program that scales with clinical severity, ionic cobalt penetrates more deeply and preferentially engages interferon and antiviral pathways in dermal compartments, whereas cobalt nanoparticles are retained more superficially and are associated with epithelial differentiation programs.