ECP is an immunotherapy approved for cutaneous T-cell lymphoma and recommended for patients with blood involvement. That is, CTCL cells detected in the blood (Sezary Syndrome and Stage III Erythrodermic MF).  

In this one and a half to three hour procedure a portion of the patient's blood is removed from the vein, and placed into a portable machine that separates the white blood cells, mixes them with a photosensitizing drug (methoxsalen) and exposes them to ultraviolet A (UVA) light. ECP is PUVA phototherapy for white blood cells. The treated cells are then put back (re-infused) into the body through the vein.  It is well tolerated and has few side effects.

It is believed that photopheresis helps boost the immune system’s ability to fight off CTCL cells.  Patients are typically treated on two successive days, 3-4 weeks apart. Usually, six to nine treatments are required before a therapeutic effect may be seen. Photopheresis is often combined with other therapies such as interferons or bexarotene.