Efficacy of a 365 nm Ultraviolet A1 light Emitting Diode (UVA1‐LED) in in vitro Extracorporeal Photopheresis

Abstract

Extracorporeal photochemotherapy (ECP) is one of the more effective cell therapies for graft‐versus‐host disease (GvHD). ECP is a widely recommended therapeutic approach for the treatment of chronic GvHD, particularly steroid‐refractory GVHD. In recent years, the use of a light emitting diode (LED) in the clinic has attracted considerable interest. In this study, we examined the issue of whether an ultraviolet A1‐light emitting diode (UVA1‐LED) can be used as a light source in ECP. To compare the efficacy of ECP with conventional UVA lamp and a UVA1‐LED, we established an in vitro ECP model. Treatment efficacy was evaluated by measuring the % apoptosis and the inhibition of T‐cell proliferation. To investigate the effect of ECP on the innate immune reaction, THP‐1 cells with a luciferase reporter gene driven by a NF‐kB response element (THP‐1 luc NF‐kB) were treated with ECP. The LED‐ECP induced apoptosis and inhibition of T‐cell proliferation as efficiently as a conventional ECP. However, LED‐ECP induced less innate immunity in THP‐1. Since LED devices are more compact compared with conventional UVA irradiation devices, the use of a UVA1‐LED in the treatment of ECP may be a better alternative to conventional ECP therapy.