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.
Apoptosis ; Graft vs Host Disease ; prevention & control ; therapy ; Humans ; Immune Tolerance ; Photopheresis ; methods

Chronic graft-versus-host disease (cGVHD) is a common complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT), which is also one of the major causes of patients' death following transplantation. Recently, extracorporeal photochemotherapy (ECP) has shown a considerable efficacy in cGVHD treatment, which is based on the infusion of autologous peripheral blood mononuclear cells collected by aphesis, incubated with the photoactivable drug 8-methoxypsoralen (8-MOP) and UV-A irradiation. The therapeutic effect of ECP is mainly achieved by the induction of cell apoptosis, influencing the function of dendritic cells and the induction of immune tolerance. ECP has many advantages in the treatment of cGVHD, such as no increasing the risk of infection in patients, unaffecting the graft-versus-leukemia effect, nearly no side effect and so on. Many medical centers have done a lot of research on the treatment of cGVHD in both children and adults by using ECP and achieved good results. CD19(+) CD21(-) B lymphocytes, serum BAFF and serum TNFα can be used to measure and early evaluate the efficacy of ECP treatment. The effect of ECP is associated with many factors, and certain complications may occur during the treatment. At present, the application of ECP treatment is limited by the unclear mechanisms, varying treatment cycles in different studies, and small number of patients in clinical research. In the near future, with deeper basic research, increasing the case number and standard clinical treatment, ECP will have a more extensive application prospects. This review focuses mainly on the clinical advances of ECP in the treatment of cGVHD.
Apoptosis ; Graft vs Host Disease ; Humans ; Leukocytes, Mononuclear ; Photochemotherapy ; Photopheresis ; Ultraviolet Rays

BACKGROUND: The safety of extracorporeal photopheresis (ECP) in steroid-refractory chronic graft-versus-host disease (SR-cGVHD) has been explored in multiple studies but reported response rates (RR) vary significantly across studies. METHODS: We conducted a meta-analysis to assess the efficacy of ECP for SR-cGVHD. A search of electronic databases for studies published between 1984 and 2012 was conducted. End points included RR: complete response (CR), overall response rates (ORR), and organ-specific RR. The initial search generated 312 studies, of which 18 met the selection criteria (N=595). A random effects model was used for pooled rates. RESULTS: Pooled CR rates and ORR were 29% (confidence interval [CI], 19-42%) and 64% (CI, 65-82%), respectively. One-year overall survival was available for 4 studies only and was 49% (CI, 29-70%). The pooled RR for skin, liver, ocular, oral, lung, gastrointestinal and musculoskeletal SR-cGVHD was 74%, 68%, 60%, 72%, 48%, 53%, and 64%, respectively. There was a significant heterogeneity among studies due to differences in ECP schedules and duration. No significant differences in responses to ECP for pediatric and adult populations were found. Sensitivity analysis could not be undertaken due to a limited number of prospective studies. CONCLUSION: ECP is an effective therapy for oral, skin, and liver SR-cGVHD, with modest activity in lung and gastrointestinal SR-cGVHD.
Adult ; Appointments and Schedules ; Graft vs Host Disease* ; Humans ; Liver ; Lung ; Patient Selection ; Photopheresis* ; Population Characteristics ; Skin

BACKGROUND: The mortality of patients with steroid resistant acute graft-versus-host disease (GVHD) after allogeneic hematopoietic stem cell transplantation (HSCT) is high due to multiple organ failure and infection. Recently, the use of extracorporeal photopheresis (ECP), which is believed to have a low risk of infection, has been applied for the treatment of GVHD. METHODS: Of 23 patients who were steroid resistant acute GVHD that was resistant even to high dose steroid treatment as second-line treatment, 10 patients received ECP (ECP group) and 13 patients received a third-line treatment other than ECP (non-ECP group). The outcome including the response rate and survival for the ECP group and non-ECP group was analyzed. RESULTS: The response rate of the ECP group including complete remission and partial remission, was 30%. The survival rate was 30% for the ECP group and 0% for the non-ECP group. The estimated mean survival time was 229.3+/-89.3 days for the ECP group and 41.8+/-14.6 days for the non-ECP group (P=0.028). CONCLUSION: ECP can be considered as a treatment option for the steroid resistant acute GVHD that is refractory to high dose steroid treatment.
Graft vs Host Disease ; Hematopoietic Stem Cell Transplantation ; Humans ; Mortality ; Multiple Organ Failure ; Photopheresis* ; Survival Rate