__NOTOC__ In medicine, photopheresis (''aka'' extracorporeal photopheresis or ECP) is a form of apheresis and photodynamic therapy in which blood is subject to apheresis to separate buffy coat (

WBC WBC may stand for: Business *Westinghouse Broadcasting Company, a former large India broadcaster now folded into CBS *Westpac (New Delhi Exchange code: WBC), a multinational Financial services company *Wholesale Broadband Connect, BT Wholesale's ...

+ platelets) from whole blood, chemically treated with

8-methoxypsoralen Methoxsalen, sold under the brand name Oxsoralen among others, is a medication used to treat psoriasis, eczema, vitiligo, and some cutaneous lymphomas in conjunction with exposing the skin to ultraviolet (UVA) light from lamps or sunlight. Methox ...

(instilled into a collection bag or given per os in advance), exposed to ultraviolet light (UVA), and then returned to the patient. Activated 8-methoxypsoralen crosslinks DNA in exposed cells, ultimately resulting

apoptosis Apoptosis (from grc, ἀπόπτωσις, apóptōsis, 'falling off') is a form of programmed cell death that occurs in multicellular organisms. Biochemical events lead to characteristic cell changes (morphology) and death. These changes incl ...

of nucleated cells. The photochemically damaged T-cells returned to the patient appear to induce

cytotoxic Cytotoxicity is the quality of being toxic to cells. Examples of toxic agents are an immune cell or some types of venom, e.g. from the puff adder (''Bitis arietans'') or brown recluse spider (''Loxosceles reclusa''). Cell physiology Treating cells ...

effects on T-cell formation. The mechanism of such “antitumor” action has not been elucidated. A 1987 New England Journal of Medicine publication introduced photopheresis involving 8-methoxypsoralen., now standard U.S. Food and Drug Administration (FDA) therapy for cutaneous T-cell lymphoma. Evidence suggests that this treatment might help treat

graft-versus-host disease Graft-versus-host disease (GvHD) is a syndrome, characterized by inflammation in different organs. GvHD is commonly associated with bone marrow transplants and stem cell transplants. White blood cells of the donor's immune system which remain wit ...

, though this evidence is largely observational; controlled trials are needed to support this use. Photopheresis has also been successful in treating epidermolysis bullosa acquisita when all other treatments have been ineffective. Minimal observed side effects for patients receiving photopheresis include hypotension and syncope resulting from volume shifts during leukapheresis phase of treatment. Photopheresis is also an experimental treatment for patients with cardiac, pulmonary and renal allograft rejection,

autoimmune diseases An autoimmune disease is a condition arising from an abnormal immune response to a functioning body part. At least 80 types of autoimmune diseases have been identified, with some evidence suggesting that there may be more than 100 types. Nearly a ...

, nephrogenic systemic fibrosis and ulcerative colitis.

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Supplemental references

{{Reflist, group=supp 3. Maceira Rozas MC. Fotoaféresis para pacientes con enfermedad de injerto contra huésped resistente a esteroides. Santiago de Compostela: Axencia de Avaliación de Tecnoloxías Sanitarias de Galicia, avalia-t; 2014. Available from: http://www.sergas.es/docs/Avalia-t/electroporacion/CT201402Fotoafereis_Def.pdf

External links

American Society for Apheresis

Extracorporeal photopheresis
entry in the public domain NCI Dictionary of Cancer Terms

definition at ''eMedicine.com'' Medical treatments Light therapy Blood

See also

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Supplemental references

External links