Despite the immunosuppressive therapy, acute rejection occurs frequently in the first year after transplantation and determinates the onset of chronic rejection, which is the major cause of graft loss in the long run. The aim of this project is to evaluate the efficacy and safety of Extracorporeal Photopheresis (ECP) for prevention of acute reject in recipients affected by cystic fibrosis in the first year after lung transplantation. The hypothesis is ECP could induce graft immunotolerance regulating T-cells activity and inflammatory responses. CF patients referring for transplant to Milan Transplant Center will be included: 24 patients are expected and included in two years. After transplantation, they will be randomly allocated to current therapies or to ECP besides current therapies.