title: Exposure to UVB induces accumulation of LFA-1+ T cells and enhanced expression of the chemokine psoriasin in normal human skin.
abstract: Normal human skin shows preferential (epi)dermal infiltration of CD4+ T cells upon acute UV exposure. To study the mechanism behind this feature we locally exposed healthy volunteers to doses of UV commonly encountered by the population. Expression of integrins on T cells and expression of adhesion molecules on dermal endothelial cells were quantitatively assessed by immunohistochemistry in situ. We also investigated the effects of ultraviolet-B (UVB) exposure on psoriasin and IL-16, two specific chemoattractant factors for CD4+ T cells, at messenger RNA (mRNA) level by semiquantitative reverse transcriptase-polymerase chain reaction and at protein level by immunohistochemistry. We found, at day 2 after exposure to four minimal erythema doses of UVB, predominant accumulation of LFA-1+/CLA-/VLA-4- T cells in the dermis. Concomitantly the expression of ICAM-1, but not that of E-selectin and VCAM-1, was upregulated on dermal endothelial cells. The increase in the number of dermal T cells was not due to proliferation because only 2% of the UVB-induced dermal T cells expressed the marker of proliferation Ki-67. Whereas exposure to 35 J/cm2 of ultraviolet-A (UVA), like UVB, induced a loss of intraepidermal T cells at day 2 after exposure, UVA induced neither any influx of T cells into the dermis nor any adhesion molecule upregulation on endothelial cells. In response to UVB exposure, the expression of psoriasin mRNA, but not of IL-16 mRNA, was upregulated; the expression of psoriasin protein was also found to be upregulated. These results suggest that LFA-1/ICAM-1 pathway and psoriasin are both involved in the accumulation of CD4+ T cells into UVB-irradiated skin, possibly via a recruitment mechanism.
authors.affiliation: Department of Dermatology, Academic Medical Center, University of Amsterdam, The Netherlands. s.dinuzzo@amc.uva.nl
authors.forename: S
authors.initials: S
authors.lastname: Di Nuzzo
authors.forename: R M
authors.initials: RM
authors.lastname: Sylva-Steenland
authors.forename: C W
authors.initials: CW
authors.lastname: Koomen
authors.forename: M A
authors.initials: MA
authors.lastname: de Rie
authors.forename: P K
authors.initials: PK
authors.lastname: Das
authors.forename: J D
authors.initials: JD
authors.lastname: Bos
authors.forename: M B
authors.initials: MB
authors.lastname: Teunissen
mesh_terms: D001483:Base Sequence; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D018925:Chemokines / Q000378:metabolism*; D017931:DNA Primers; D006801:Humans; D007150:Immunohistochemistry; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000075023:S100 Calcium Binding Protein A7; D009418:S100 Proteins; D012867:Skin / Q000166:cytology / Q000378:metabolism / Q000528:radiation effects*; D013601:T-Lymphocytes / Q000378:metabolism / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D002135:Calcium-Binding Proteins; D018925:Chemokines; D017931:DNA Primers; D000075023:S100 Calcium Binding Protein A7; D009418:S100 Proteins; C089242:S100A7 protein, human