title: Ultraviolet-B irradiation decreases IFN-gamma and increases IL-4 expression in psoriatic lesional skin in situ and in cultured dermal T cells derived from these lesions.
abstract: Type 1 cytokine producing T cells play an important role in the pathogenesis of psoriasis. Ultraviolet-B (UVB) irradiation is effective in the treatment of this disease. In normal skin, UVB causes a change in dermal microenvironment, leading to a decrease of IFN-gamma expressing type 1 T cells and a concurrent increase of IL-4 expressing type 2 T cells. The aim of this study was to show whether UVB irradiation causes a like-wise shift of type 1 and type 2 responses in psoriatic skin. For this purpose, biopsies were obtained from the lesional skin of psoriatic patients before, 2 days and 14 days after a single exposure to 4 MED UVB. Sections from these biopsies were immunostained (CD3, IFN-gamma and IL-4) or RNA was extracted and analyzed for the expressions of IFN-gamma and IL-4 by PCR. In addition, primary cultures of T cells from dermal cell suspensions were stained intracellularly for IFN-gamma and IL-4 expression and CD4+ and CD8+ T subsets were analyzed by flow cytometry. IFN-gamma was abundantly expressed in situ before irradiation and decreased in all patients after UVB irradiation, whereas IL-4 expression was variably expressed before irradiation and increased in different degrees after irradiation. Cytokine mRNA expressions determined by PCR showed a clear decrease of IFN-gamma and increase of IL-4 following UVB irradiation. Both CD4+ and CD8+ dermal T cells were found to produce less IFN-gamma and more IL-4 following UVB irradiation as determined by flow cytometry. Decrease in IFN-gamma expression and increase in IL-4 expression of dermal T cells in psoriatic lesions after UVB irradiation may lead to decrease in local immunoreactivity. These changes could be part of the therapeutic effects of UVB on psoriasis.
authors.affiliation: Department of Dermatology, Academic Medical Center Amsterdam, The Netherlands. g.piskin@amc.uva.nl
authors.forename: Gamze
authors.initials: G
authors.lastname: Piskin
authors.forename: Cornelis W
authors.initials: CW
authors.lastname: Koomen
authors.forename: Daisy
authors.initials: D
authors.lastname: Picavet
authors.forename: Jan D
authors.initials: JD
authors.lastname: Bos
authors.forename: Marcel B M
authors.initials: MB
authors.lastname: Teunissen
mesh_terms: D001483:Base Sequence; D002478:Cells, Cultured; D015870:Gene Expression / Q000528:radiation effects; D006801:Humans; D007150:Immunohistochemistry; D007371:Interferon-gamma / Q000235:genetics / Q000378:metabolism*; D015847:Interleukin-4 / Q000235:genetics / Q000378:metabolism*; D011565:Psoriasis / Q000235:genetics / Q000276:immunology* / Q000532:radiotherapy*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012867:Skin / Q000276:immunology / Q000378:metabolism / Q000528:radiation effects; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism / Q000528:radiation effects; D014467:Ultraviolet Therapy
chemical_list: D012333:RNA, Messenger; D015847:Interleukin-4; D007371:Interferon-gamma