Epidermal dendritic cells found in in£amed skin include Langerhans cells and the recently identi¢ed population of in£ammatory dendritic epidermal cells. Another subset of dendritic cells in humans is the plasmacytoid dendritic cell in peripheral blood, which is characterized by the production of large amounts of type I interferon (interferon-a and interferon-b) upon viral infection. We hypothesized that plasmacytoid dendritic cells might be involved in anti-viral defense mechanisms of the skin. Here we investigated plasmacytoid dendritic cells, in£ammatory dendritic epidermal cells, and Langerhans cells in epidermal single cell suspensions of normal looking skin from healthy volunteers and of lesional skin from patients with different in£ammatory skin diseases. Langerhans cells were found in normal and in in£amed skin samples. In normal skin, plasmacytoid dendritic cells and in£am-matory dendritic epidermal cells were low or absent. Lesional skin samples from patients with psoriasis vulgaris and contact dermatitis contained relatively high numbers of both in£ammatory dendritic epidermal cells and plasmacytoid dendritic cells. In contrast, many in£ammatory dendritic epidermal cells but only very few plasmacytoid dendritic cells could be detected in atopic dermatitis lesions. Lupus erythematosus was characterized by high numbers of plasmacytoid dendritic cells but low numbers of in£ammatory dendritic epidermal cells. These results demonstrate that in addition to resident Langerhans cells, plasmacytoid dendritic cells and in£ammatory dendritic epidermal cells are selectively recruited to the skin lesions depending on the type of skin disease. The lack of plasmacytoid dendritic cells in atopic dermatitis may predispose atopic dermatitis patients to viral infections such as eczema herpeticum, a secondary infection of atopic dermatitis lesions with herpes simplex virus. The composition of dendritic cell subsets may help to clarify the etiology of in£ammatory skin diseases and forms the basis for therapeutic intervention with selective microbial molecules such as immunostimulatory CpG oligonucleotides.
In REF was presented how plasmacytoid dendritic cells, inflammatory dendritic epidermal cells, and Langerhans cells influence anti-viral skin defense mechanism.
Plasmacytoid Dendritic Cells: A New Cutaneous Dendritic Cell Subset with Distinct Role in Inflammatory Skin Diseases
The Journal of investigative dermatology
The Journal of investigative dermatology
Medicine Biology