A novel UVA1 phototherapy using light-emitting diodes for scleroderma treatment

UVA1 phototherapy selectively uses the longer-wavelength UVA1 light of 340–400 nm and does not use the shorter-wavelength UVA2 (320–340 nm) or UVB wavelengths (290–320 nm) that cause an erythema reaction. Several studies have reported the effectiveness of UVA1 therapy for diseases in which T cells infiltrate the dermis and excessive collagen accumulates, such as atopic dermatitis, T-cell lymphoma, and systemic sclerosis. The wavelength specificity within the UVA1 range, however, has not been clarified. Although metal-halide lamps are commonly used as the light source for UVA1 therapy due to their high intensity, they are not efficient because of their a broad spectrum, ranging from ∼200 nm to 500 nm, and three filters are needed to remove the unnecessary wavelengths. Therefore, we investigated the wavelength characteristics of the AlGaN and InGaN system light-emitting diodes (LED) to develop a more effective and efficient UVA1 delivery system. Fibroblast cells were irradiated with monochrome UVA1 light using UV-LEDs. After irradiation, the cells were incubated and matrix metalloproteinase-1 (MMP-1) and Transforming Growth Factor-beta typeII Receptor (TGFBRII) RNA expressions were measured using the real-time polymerase chain reaction. Our findings indicated that MMP-1 was significantly increased, and TGFBR-II was decreased by irradiation in the UVA1 wavelength region. These findings indicate that UV-LEDs are a promising light source for UVA1 phototherapy machines.