Maari Catherine, Viau Gilles, Bissonnette Robert
Division of Dermatology, University of Montreal Hospital Centre, Quebec, Canada.
J Am Acad Dermatol. 2003 Jul;49(1):55-8. doi: 10.1067/mjd.2003.445.
Increased endogenous levels of protoporphyrin IX (PpIX) have been reported in the skin of patients with psoriasis. Activation of PpIX with blue light after exogenous topical application of its precursor, aminolevulinic acid, can improve psoriasis. Light activation of endogenous PpIX for the treatment of psoriasis has never been studied.
The purpose of this study was to determine the efficacy of multiple exposures to blue light in patients with plaque psoriasis.
A total of 17 patients with plaque psoriasis presenting increased endogenous level of PpIX were enrolled. Of the 2 identified plaques on each patient, 1 was exposed to 10 J/cm(2) of blue light from a fluorescent panel 3 times per week for 4 consecutive weeks. Plaque severity was assessed in a blinded fashion. PpIX levels were measured with in vivo fluorescence spectroscopy weekly.
A single exposure to blue light induced almost complete photobleaching of PpIX. There was no significant difference between the mean psoriasis severity score of the plaques before and after 12 exposures to blue light.
Repeated exposure to blue light did not improve psoriasis.
据报道，银屑病患者皮肤中原卟啉IX（PpIX）的内源性水平升高。在局部外用其前体氨基乙酰丙酸后，用蓝光激活PpIX可改善银屑病。从未研究过用蓝光激活内源性PpIX治疗银屑病。
本研究旨在确定多次暴露于蓝光对斑块状银屑病患者的疗效。
共纳入17例斑块状银屑病患者，其PpIX内源性水平升高。在每位患者身上确定的2个斑块中，1个每周接受3次来自荧光板的10 J/cm²蓝光照射，连续照射4周。以盲法评估斑块严重程度。每周用体内荧光光谱法测量PpIX水平。
单次暴露于蓝光几乎可使PpIX完全光漂白。12次蓝光照射前后斑块的平均银屑病严重程度评分无显著差异。
重复暴露于蓝光并不能改善银屑病。
