In vivo ultraviolet irradiation of human skin results in profound perturbation of the immune system. Relevance to ultraviolet-induced skin cancer

Topical Grape Seed Proanthocyandin Extract Reduces Sunburn Cells and Mutant p53 Positive Epidermal Cell Formation, and Prevents Depletion of Langerhans Cells in an Acute Sunburn Model

“…Similarly, depletion of the number of Langerhans cells in the epidermis after UV irradiation has been well documented, and this results in immunosuppression and even photocarcinogenesis. 17 In our study, the reduction or disappearance of Langerhans cells happened after exposure to 2 MED SSR; however, topical application of GSPE before UV exposure resulted in almost equally total reconstitution of this epidermal immune cell population. We also found an interesting phenomenon: more dendrites and longer dendrites in most Langerhans cells could be seen in the skin areas that were pretreated with topical GSPE.…”

Urocanic acid suppresses induction of immunity in human skin

“…Exposure of human or animal skin to UV radiation, locally or systemically, suppresses the immune response (12)(13)(14)(15). The mechanism is uncertain.…”

Photoimmunology of Lupus Erythematosus and Dermatomyositis: A Speculative Review

“…Peripherally acquired, antigen-specific immune tolerance occurs in normal murine and human skin following relatively low doses of UVB irradiation (143)(144)(145). One school of thought suggests that UVR induction of IL-10 by epidermal keratinocytes or other cells in the skin might play an important role in the generation of CD8' suppressor cells that mediate this state of UVR-induced local tolerance (I 45).…”