The Principle of UVA PIT Photo Immune Therapy (Photopheresis)

Photopheresis (also known as extracorporeal photopheresis or ECP) is a therapy where the patient’s blood is collected to harvest the white blood cells with an apheresis system. The collected white blood cells (buffy coat) are treated with a photosensitizer / photoactivator and subsequently are being irradiated with UVA light. This photoactivation has fundamental influence to the cell process and leads to an alteration and activation of the patient’s own immune system.

Usually existing hospital services like haematology, transfusion medicine or blood bank already have a cell separator available (mono or dual needle flow continuous or discontinuous), which allows safe and high efficient leukapheresis in a fast manner with optimal buffy coat and high concentration of monocytes.

The Photo Immune Therapy is usually done by three principal phases:

• The collection phase where lymphocytes and mononuclear cells are collected, preferably highly concentrated with low haematocrit
• The irradiation phase in which the buffy coat is being irradiated with UVA light (2 J/cm²) under the presence of a photoactivator (8-MOP = 8 Methoxypsoralene).
• The reinfusion phase where the treated cells are reinfused into the patient.

PIT Medical Systems GmbH develops technologies for the most important part of the photopheresis.

Side Effects

• Due to the ex vivo treatment the side effects of the photopheresis treatment for the patient are minimal.
• The possible side effect is light sensitivity (with oral 8-MOP), which is why the patient should wear UVA protective sunglasses and avoid direct sunlight exposure for ca. 24 hours after the treatment.