UVR component of sunlight is immunomodulatory with suppression of cellular immunity to antigens applied at both irradiated and non-irradiated sites. Via isomerization of trans-urocanic acid in the stratum corneum to its more soluble cis isomer, UVR activates peripheral sensory nerves for release of calcitonin gene-related protein and substance P. Dermal mast cells activated by neuropeptides contribute to the immunomodulatory properties of UV. UVR-induced keratinocyte nerve growth factor production augments activation of peripheral sensory nerves for neuropeptide release. UVR-induced keratinocyte α-melanocyte stimulating hormone is immunosuppressive by stimulating keratinocyte IL-10 production, as well as increasing melanogenesis and repair of UV-induced DNA damage in melanocytes and keratinocytes. There is debate upon whether UVA wavelengths (400-320nm) have immunosuppressive properties similar to those of UVB (320-290nm).
|Title of host publication||Neuroimmunology of the Skin|
|Subtitle of host publication||Basic Science to Clinical Practice|
|Publisher||Springer, Berlin, Heidelberg|
|Number of pages||12|
|Publication status||Published - 1 Dec 2009|