Stimulation of Langerhans cells with ketoprofen plus UVA in murine photocontact dermatitis to ketoprofen

Background: Ketoprofen (KP) clinically evokes the allergic type of photocontact dermatitis when applied to the skin and irradiated with ultraviolet A (UVA). We have established a murine model of photocontact dermatitis to KIP, which is a T cell-mediated delayed type hypersensitivity. Objective: To further explore the mechanism underlying this sensitivity, we investigated whether KIP plus UVA activates the antigen-presenting ability of Langerhans cells (LCs). Methods: We analyzed the expression of surface molecules on LCs in the murine epidermis treated with KIP plus UVA by immunohistochemistry and flow cytometry. Changes in the cytokine expression of epidermal cells from KP-phototreated skin were also examined by real-time PCR. Results: LCs became larger after treatment with KIP plus UVA. The number of LCs was significantly decreased 2-3 days after KIP phototreatment and recovered on day 5. A flow cytometric analysis revealed that KIP plus UVA increased the percentage of LCs that highly expressed MHC class 11, CD86, CD80, CD54 and CD40, whereas neither KIP nor UVA alone enhanced the expression. KP phototreatment augmented the expression of I-A and CD86 on LCs in KIP and UVA dose-dependent manners. A real-time IPCR analysis of KP-phototreated skin showed that the expression of mRNA for IL-1 alpha and GM-CSF was immediately increased after treatment.