Advances of mechanism study on extracorporeal photochemotherapy to treat and prevent graft-versus-host disease in vitro--review / 中国实验血液学杂志

ABSTRACT

Extracorporeal photochemotherapy, also called extracorporeal photopheresis, or ECP for short, is now an effective method to treat and prevent patients from graft-versus-host disease (GVHD). It is generally accepted that the mechanism of ECP is to induce immune tolerance. Further researches show that ECP acts on several stages of GVHD by means of many complex mechanisms. Firstly, ECP induces apoptosis of T lymphocytes, inhibiting T cells from differentiating and proliferating, and promoting regulatory T cells. Besides, it also adjusts the number and proportion of helper T cells. Secondly, ECP affects antigen presenting cells. It induces apoptosis and inhibits maturation of antigen presenting cells. At the same time it affects the ability to process and present antigens of antigen presenting cells. Thirdly, ECP adjusts the cytokine secretion, in order to inhibit inflammatory response. This review discusses why ECP can treat and prevent patients from GVHD via the three aspects mentioned above.