Holien Toril, Gederaas Odrun Arna, Darvekar Sagar Ramesh, Christensen Eidi, Peng Qian
Department of Clinical and Molecular Medicine, NTNU-Norwegian University of Science and Technology, N-7491, Trondheim, Norway.
Department of Hematology, St. Olav's University Hospital HF, Trondheim, N-7491, Norway.
Lasers Surg Med. 2018 Jul;50(5):469-475. doi: 10.1002/lsm.22806. Epub 2018 Feb 20.
Extracorporeal photopheresis (ECP), an established modality for cutaneous T-cell lymphoma (CTCL) and graft-versus-host disease, involves ex vivo treatment of isolated leukocytes of a patient with the photosensitizing drug 8-methoxypsoralen (8-MOP) and ultraviolet-A (UV-A) exposure before reinfusion back to the patient. However, 8-MOP binds to both diseased and normal cells and thus kills both types of the cells after UV-A illumination with little selectivity. Clinically, this modality gives only partial response in the majority of treated patients. 5-Aminolevulinic acid (5-ALA), a precursor of the potent photosensitizer protoporphyrin IX (PpIX), has been shown to selectively induce PpIX in activated T lymphocytes (T cells) and could be an alternative for 8-MOP. The objectives of this study were to investigate ex vivo 5-ALA dark toxicity, 5-ALA-induced PpIX production, and photodynamic effect on T cells obtained from clinical ECP patients after the treatment of 5-ALA or 8-MOP plus a built-in certified UV-A source in the commercial Therakos™ Photopheresis System.
Flow cytometry was used to study dark cytotoxic effects of 5-ALA on human leukocytes, to measure the production of 5-ALA-induced PpIX in CD25 activated T cells from both diluted mononuclear cells and undiluted buffy coat samples of ECP patients and to compare photodynamic effects on CD4 and CD8 T cells with 5-ALA/UV-A or 8-MOP/UV-A.
No dark toxicity of 5-ALA on the leukocytes of ECP patients was seen at concentrations up to 10 mM for an incubation of up to 20 hours. 5-ALA-induced PpIX was produced more in CD25 activated T cells than resting T cells in both diluted mononuclear cells and undiluted buffy coat samples, although there was a huge variation of samples from different individual patients. The CD4 and CD8 T cells treated with 5-ALA/UV-A were killed more than those treated with 8-MOP/UV-A.
These results suggest that 5-ALA/UV-A may have the potential for improving the efficacy of ECP. Lasers Surg. Med. 50:469-475, 2018. © 2018 Wiley Periodicals, Inc.
体外光化学疗法（ECP）是一种用于治疗皮肤T细胞淋巴瘤（CTCL）和移植物抗宿主病的既定方法，该方法包括用光敏药物8-甲氧基补骨脂素（8-MOP）对患者分离出的白细胞进行体外处理，并在重新注入患者体内之前进行紫外线A（UV-A）照射。然而，8-MOP会与患病细胞和正常细胞都结合，因此在UV-A照射后会无差别地杀死这两种细胞。临床上，这种方法在大多数接受治疗的患者中仅产生部分反应。5-氨基乙酰丙酸（5-ALA）是强效光敏剂原卟啉IX（PpIX）的前体，已被证明能在活化的T淋巴细胞（T细胞）中选择性诱导PpIX生成，可能是8-MOP的替代物。本研究的目的是在商业Therakos™光化学疗法系统中，利用内置的经认证的UV-A光源，研究5-ALA对临床ECP患者获得的T细胞的体外暗毒性、5-ALA诱导的PpIX生成以及光动力效应，比较5-ALA或8-MOP处理后的情况。
采用流式细胞术研究5-ALA对人白细胞的暗细胞毒性作用，测量来自ECP患者稀释单核细胞和未稀释血沉棕黄层样本中CD25活化T细胞的5-ALA诱导的PpIX生成情况，并比较5-ALA/UV-A或8-MOP/UV-A对CD4和CD8 T细胞的光动力效应。
在浓度高达10 mM且孵育时间长达20小时的情况下，未观察到5-ALA对ECP患者白细胞的暗毒性。在稀释单核细胞和未稀释血沉棕黄层样本中，5-ALA诱导的PpIX在CD25活化T细胞中的生成量均高于静息T细胞，尽管不同个体患者的样本存在巨大差异。用5-ALA/UV-A处理后的CD4和CD8 T细胞比用8-MOP/UV-A处理后的细胞死亡更多。
这些结果表明5-ALA/UV-A可能具有提高ECP疗效的潜力。《激光外科与医学》50:469 - 475，2018年。© 2018威利期刊公司
