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In
medicine
Medicine is the science and practice of caring for a patient, managing the diagnosis, prognosis, prevention, treatment, palliation of their injury or disease, and promoting their health. Medicine encompasses a variety of health care pr ...
, photopheresis (''aka'' extracorporeal photopheresis or ECP)
is a form of
apheresis
Apheresis ( ἀφαίρεσις (''aphairesis'', "a taking away")) is a medical technology in which the blood of a person is passed through an apparatus that separates out one particular constituent and returns the remainder to the circulation ...
and
photodynamic therapy
Photodynamic therapy (PDT) is a form of phototherapy involving light and a photosensitizing chemical substance, used in conjunction with molecular oxygen to elicit cell death (phototoxicity).
PDT is popularly used in treating acne. It is used cl ...
in which
blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the cir ...
is subject to apheresis to separate
buffy coat
The buffy coat is the fraction of an anticoagulated blood sample that contains most of the white blood cells and platelets following centrifugation. It is rich in a number of immune cells including leukocytes, granulocytes.
Description
Aft ...
(
WBC +
platelet
Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby i ...
s) from whole blood, chemically treated with
8-methoxypsoralen (instilled into a collection bag or given
per os
Oral administration is a route of administration where a substance is taken through the mouth. Per os abbreviated to P.O. is sometimes used as a direction for medication to be taken orally. Many medications are taken orally because they are ...
in advance), exposed to
ultraviolet light (UVA), and then returned to the patient. Activated 8-methoxypsoralen
crosslinks DNA in exposed cells, ultimately resulting
apoptosis of
nucleated cells.
[ The photochemically damaged ]T-cell
A T cell is a type of lymphocyte. T cells are one of the important white blood cells of the immune system and play a central role in the adaptive immune response. T cells can be distinguished from other lymphocytes by the presence of a T-cell r ...
s returned to the patient appear to induce cytotoxic effects on T-cell formation. The mechanism of such “antitumor” action has not been elucidated.
A 1987 New England Journal of Medicine
''The New England Journal of Medicine'' (''NEJM'') is a weekly medical journal published by the Massachusetts Medical Society. It is among the most prestigious peer-reviewed medical journals as well as the oldest continuously published one.
His ...
publication introduced photopheresis involving 8-methoxypsoralen.U.S. Food and Drug Administration
The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...
(FDA) therapy for cutaneous T-cell lymphoma
T-cell lymphoma is a rare form of cancerous lymphoma affecting T-cells. Lymphoma arises mainly from the uncontrolled proliferation of T-cells and can become cancerous.
T-cell lymphoma is categorized under Non-Hodgkin lymphoma (NHL) and represents ...
. Evidence suggests that this treatment might help treat graft-versus-host disease, though this evidence is largely observational; controlled trials are needed to support this use.side effect
In medicine, a side effect is an effect, whether therapeutic or adverse, that is secondary to the one intended; although the term is predominantly employed to describe adverse effects, it can also apply to beneficial, but unintended, consequence ...
s for patients receiving photopheresis include hypotension
Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure (the top number) and the dia ...
and syncope resulting from volume shifts during leukapheresis
Leukapheresis () is a laboratory procedure in which white blood cells are separated from a sample of blood. It is a specific type of apheresis, the more general term for separating out one particular constituent of blood and returning the remain ...
phase of treatment. Photopheresis is also an experimental treatment for patients with cardiac, pulmonary and renal allograft
Allotransplant (''allo-'' meaning "other" in Greek) is the transplantation of cells, tissues, or organs to a recipient from a genetically non-identical donor of the same species. The transplant is called an allograft, allogeneic transplant, o ...
rejection, graft-versus-host disease, autoimmune diseases, nephrogenic systemic fibrosis
Nephrogenic systemic fibrosis is a rare syndrome that involves fibrosis of skin, joints, eyes, and internal organs. NSF is caused by exposure to gadolinium in gadolinium-based MRI contrast agents (GBCAs) in patients with impaired kidney function ...
and ulcerative colitis
Ulcerative colitis (UC) is a long-term condition that results in inflammation and ulcers of the colon and rectum. The primary symptoms of active disease are abdominal pain and diarrhea mixed with blood (hematochezia). Weight loss, fever, and ...
.
See also
*Blood irradiation therapy
Blood irradiation therapy is an alternative medical procedure in which the blood is exposed to low level light (often laser light) for therapeutic reasons. The practice was originally developed in the United States, but most recent research on i ...
Notes
References
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