Cells in the skin

Co-regulation of Epidermal Permeability Barrier and Cutaneous Immunity: The epidermal permeability barrier is no longer viewed solely as a physical barrier against molecules and microorganisms passing through skin. In addition to regulating epidermal proliferation and lipid production, epidermal permeability barrier function and cutaneous immune functions are also co-regulated. A compromised epidermal permeability barrier upregulates a wide range of cutaneous immune responses, including the expression of cytokines, antimicrobial peptides, and Toll-like receptors. Moreover, perturbation of the epidermal permeability barrier stimulates T cell proliferation, Langerhans cell infiltration and maturation, and mast-cell infiltration. Furthermore, barrier disruption enhances Staphylococcus aureus colonization and certain Candida invasions. Certain cytokines, Toll-like receptors, and antimicrobial peptides benefit the epidermal permeability barrier. Clinically, improvement of epidermal permeability barrier function is a valuable approach to prevent and treat certain immune-mediated dermatoses.