Ultraviolet light‐emitting‐diode irradiation inhibits TNF‐α and IFN‐γ‐induced expression of ICAM‐1 and STAT1 phosphorylation in human keratinocytes

Background and Objectives: Ultraviolet light-emitting diodes (UV-LEDs) are a novel light source for phototherapy. This research investigated the in vitro safety and efficacy of UV-LEDs as a phototherapeutic device for atopic dermatitis (AD). Study Design/Materials and Methods: Human keratinocytes and fibroblasts were irradiated by UV-LEDs with a center wavelength of 310 and 340 nm. We examined the effects of UV-LED irradiation on the suppression of TNF-alpha/IFN-gamma-induced activation of STAT1 and ICAM-1 and on NF-kappa B expression; we used the following methods: cell viability assay, reverse transcription-polymerase chain reaction, enzyme-linked immunosorbent assay, Western blotting, and immunocytochemistry. Results: We observed anti-inflammatory responses through the suppression of TNF-alpha/IFN-gamma-induced expression of TARC and MCP-1/CCL2, IL-1beta, IL-6, and sICAM-1 via blockage of ICAM-1 activation and subsequent activation of STAT1 and NF-kappa B. The results suggested that UV-LED irradiation inhibited ICAM expression by suppressing TNF-alpha/IFN-gamma-induced NF-kappa B activation in vitro. Conclusion: We concluded that novel UV-LED (310 and 340 nm) modalities were effective for the treatment of AD and may be promising for the treatment of inflammatory skin diseases. Lasers Surg. Med. 47:824-832, 2015. (C) 2015 Wiley Periodicals, Inc.