title: Whole-body UVB (TL-01) or UVA-1 irradiation does not alter the levels of immunomodulatory cytokines in the serum of human volunteers.
abstract: OBJECTIVE
  Ultraviolet (UV) exposure of mammalian skin induces local and systemic immunosuppression. In mice it has been proposed that systemic immunosuppression is mediated by an UV-induced cytokine cascade involving systemic interleukin (IL)-4 and IL-10 and a reduction in IL-12 activity. To investigate whether there was a parallel mechanism in humans we examined the effect of whole-body narrowband ultraviolet B (UVB) (311-313 nm; TL-01) and ultraviolet A (UVA)-1 (340-400 nm) on serum cytokine levels.
  
  
  RESULTS
  In a first study, five male psoriatic subjects were whole-body irradiated with three sessions of a standard UVB (TL-01) phototherapy regimen previously shown to cause downregulation of natural killer cell activity and T helper 1 (Th1) and Th2 cytokine production by peripheral blood mononuclear cells. Enzyme-linked immunoabsorbent assay (ELISA) of sera taken before and after the third session showed no effect of phototherapy on IL-10 and tumour necrosis factor-alpha (TNF-alpha). In a second study, five healthy subjects received three whole-body exposures of UVB (TL-01) and five other healthy subjects received three exposures of UVA-1 on alternate days (total 22 J/cm(2)). Blood samples were taken before the first irradiation and at 0, 4, 8, 12, 14, 24 and 48 h after the third irradiation. The sera were subsequently analysed for IL-10, IL-12, IL-8, IL-1beta and TNF-alpha, by ELISA. The levels of IL-1beta and TNF-alpha were below detection limits (<5 pg/ml), while no significant change in the levels of IL-10, IL-12 or IL-8 was detected as a result of either TL-01 or UVA-1.
  
  
  CONCLUSIONS
  It seems unlikely that a modulation in these circulating cytokines assessed in this study accounts for systemic UV-induced immunosuppression in human subjects.
authors.affiliation: Photobiology Unit, Ninewells Hospital and Medical School, Dundee, UK. p.mcLoone@ed.ac.uk
authors.forename: P
authors.initials: P
authors.lastname: McLoone
authors.forename: I
authors.initials: I
authors.lastname: Man
authors.forename: S
authors.initials: S
authors.lastname: Yule
authors.forename: A
authors.initials: A
authors.lastname: Fluitman
authors.forename: H
authors.initials: H
authors.lastname: Van Loveren
authors.forename: M
authors.initials: M
authors.lastname: Norval
authors.forename: N K
authors.initials: NK
authors.lastname: Gibbs
mesh_terms: D016207:Cytokines / Q000097:blood*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D008297:Male; D011565:Psoriasis / Q000532:radiotherapy*; D014467:Ultraviolet Therapy
chemical_list: D016207:Cytokines