Additional Study Information: This study is for patients who have had a lung transplant and whose doctors believe that their body is rejecting the new lung, resulting in damage to the transplanted lung or lungs. This condition is called Bronchiolitis Obliterans Syndrome (BOS). In some patients, BOS progressively worsens, causing more breathing difficulty, worse quality of life. We are studying ways to prevent and to limit BOS from worsening in lung transplant patients. Extracorporeal Photopheresis (ECP) is another treatment that can be used in some patients with BOS. With ECP, a special machine is used to remove blood from the body through a catheter (small tube) that is placed in the vein.