Kinetic Profile of Inflammation Markers in Human Skin In vivo Following Exposure to Ultraviolet B Indicates Synchronic Release of Cytokines and Prostanoids.

Ultraviolet B (UVB) irradiation affects epidermal cells, which respond via a cascade of inflammation markers. After initial in vitro and ex vivo experiments, this study used cutaneous microdialysis to generate a kinetic profile for 16 cytokines and 4 prostanoids in human skin in vivo. Skin areas 9 cm2 were irradiated with UVB (2× minimal erythematous dose) 16 h after catheter placement in the dermis of the volar forearms of healthy volunteers. Dialysates were collected at 4-h intervals up to 64 h and analysed for 5- and 8-iso-PGF2α, 9α,11α-PGF2α and PGE2 by gas chromatography-mass spectrometry (GC/MS). Dialysates were also analysed for interleukin (IL)-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-8, IL-10, tumour necrosis factor (TNF)-α, Fas ligand (FasL), interferon-γ-inducible protein-10 (IP-10), monocyte chemoattractant protein 1 (MCP-1), RANTES, eotaxin, and granulocyte-macrophage colony-stimulating factor (GM-CSF) using a multiplex-based cytometric-bead-array. In conclusion, 3 peaks with synchronic release of T helper (TH) 1-directed inflammatory cytokines and prostanoids could be detected post-UVB: an early phase (4-12 h), an intermediate phase (16-24 h) and a late phase (32-40 h). A TH2-directed cytokine response was detectable at intermediate and late phases.