UV Zapping Of T-Cells
What is Photopheresis?
In medicine, Photopheresis is a medical treatment process used to treat a variety of diseases, one of which is GVHD. It is touted as one of the least toxic and least invasive treatment strategies available for GVHD. It is also known by the name 'Extracorporeal Photopheresis', or abbreviated as 'ECP' or just called 'photo'. Photopheresis is a form of apheresis and photodynamic therapy in which blood is treated with a photosensitizing agent and subsequently irradiated with specified wavelengths of light to achieve an effect.
What should one expect when undergoing Photopheresis?
If you don't have a line, you might expect your doctor will want you to have one, or expect to be poked each time you go to Photopheresis. Expect to call it 'Photo'. Expect to have two treatments per week, although some people have three appointments. Photo is usually quite uneventful, even mundane, so you might fall asleep. If you move in your sleep, it may affect the machine, sounding the annoying alarms that the tech must turn off when adjusting the machine. If they have a TV, you might expect to catch up on your movies, or bring tunes. Expect to be on the chilly side, bring a sweater, ask for a blanket. Bring sunglasses; you will need to wear them afterwards. Most folks tire after treatment, so you might want to arrange for a driver to go home. The better hydrated you are when you go to Photo, the better chance they have of inserting the IV, and the quicker goes the treatment.
Is Extra Corporeal Treatment the same thing?
Extra-corporeal Photopheresis, or ECP, for short, is the same thing as Photopheresis, which is often simply referred to as 'Photo'.
What type of line must a patient have for Photopheresis?
Photopheresis can be conducted through a PICC or a Central Line. Some patients have a line put in to receive treatment, but it may not be necessary. Photopheresis can also be conducted with an IV line that is inserted before each treatment. An IV line may be perferred, especially for certain people, because even though it means a poke each time, it has a lesser chance of developing an infection than does a central or PICC line.
What is involved in a photopheresis treatement?
Generally speaking, Extra-corporeal Photopheresis (ECP) exposes a patient's blood to 8-methoxypsoralen followed by UVA irradiation before returning the blood to the patient.
The photo to the left is of a Photopheresis machine. This is just one model; there are several other models, but each is pretty similar to this one. The biggest difference between machines is whether they are single lines or double lines. Single lines allow blood to flow only one way; double lines allow blood to be extracted and returned at the same time, thus reducing the total amount of time per treatment.
In a Photopheresis treatment, an IV is started, if a central line or PICC is absent. The IV is attached to the Photopheresis treatment machine. Blood is withdrawn from the patient (pumped out of the patient through the IV) and fed into a bag until a sufficient quantity is gathered (about two cups). The blood is then spun down to separate the red cells and white cells.
Red cells are deposited into a separate bag and fed back into the patient.
White cells are fed into a series of tubing that rests under a UV light. The white cells are treated with UV rays, and fed back into the patient through the same IV used to extract them. It is similar to a dialysis, except that the blood is not filtered.
How long must one undergo photopheresis treatment?
A Photopheresis treatment consists of two appointments. Each appointment is said to be half of the treatment process. A week of treatment would then entail two appointments. The appointments can be on consequetive days, or two or three days apart. in some situations, each half of the treatment can be as far apart as a week.
Initially, Photopheresis was prescribed for four weeks, and only for skin GvHD. The initial use of 'photo', as it is often called by the patients, showed remarkable (very good) results. Nearly all of the patients who were prescribed photo were positively affected by it. Their skin became less leathery, less thick, and more supple. In time, the scarring even diminished.
For those who were not showing signs of improvement within the first four weeks, the length of treatment was extended. Soon, doctors noted that patients undergoing extended Photopheresis time periods were also showing signs of improvement with other GvHD symptoms. For some patients, GvHD of the eyes was improved. For other patients, gut GvHD improved.
Patients often continue on Photopheresis for as long as is needed to improve the GvHD symptom, or until improvements cease to be seen.
How long does it take to see treatment effects?
For some, effects are seen quickly; for others, effects can take time - weeks or even months.
For those for whom effects were seen almost immediately, it was due to the occurence of a systematic destruction of leukocyte blood cells (called apoptosis). That process causes the bad T-cell cells to be suppressed and regulatory T-cells to be introduced.
Patience with skin GvHD, for example, will see effects over a longer period of time. How long? It is different for every person.
My daughter underwent Photopheresis for more than two years, and it was very successful in treating a variety of Chronic Graft-versus-Host (cGvHD) issues, rangingfrom skin (leathery, thick) to eye (required constant drops) and many other issues that weren't even realized because the photo treatments prevented them.
Photopheresis, too, differs for different people.
According to the Cancer Center of Seattle, Washington, 86% of patients with Grade II Acute GVHD recovered, 55% with Grade III and 30% with Grade IV. Complete recovery was seen in 82% of those with skin GVHD, 61% of those with liver and gut GVHD.
At the 4-year mark, 22 of 28 patients had no signs of GVHD. Transplant-related mortality at 4 years for patients with complete remission was 14%; for those without complete remission, it was 73%.
Photopheresis treatments can also result in reduction or discontinuance of steroids, without Acute Graft-versus-Host (aGvHD) flaring.
Other uses of Photopheresis
Photopheresis is used to treat other T-cell diseases, such as cutaneous T-cell Lymphoma, dermatological disorders and organ transplant rejection.
Originally, photopheresis was begun to treat skin GvHD, and it was found that other types of GvHD also improved for some people, while the photopheresis (aka photo) didn't help a relatively few number of people (see statistics above).
Photopheresis is also used in a variety of other treatments, such as the few listed below. A link is also provided below for you to search in Google Scholar and explore other treatments with Photopheresis.
- This article reveals it was used for Prevention of Rejection in Cardiac Transplantation https://www.nejm.org/doi/full/10.1056/nejm199812103392404#t=article
- Here, it is used to treat T-cell lymphoma, quite a shocking and wonderful study
- Here's a search in Google Scholar (a phenomenally great tool for the public to use to search medical journals and other esoteric publications)
Technical Answers About Photopheresis
We'll defer the more technical aspects of Photopheresis to the more knowledgeable folks, such as Dr. M. Owsianowski, or Dr. Hildegard T. Greinix, and Dr. Fred Hutchinson Cancer Research Center, Seattle, WA as published in the Blood Journal as an excellent source of sound information.
Books - Blankets - Sunglasses
The treatments take a while, so it may help to have a book. Often times, folks are tired during the treatment, and just want to sleep. It seems most folks want to eat at some point. It is boring. Because blood is being taken out of the body and then returned, it often causes one to become chilled, even cold, so having a blanket helps. Even hot blankets can be used to warm you up faster. Patients are cautioned to wear UV-protection on their eyes after a treatment.
Here are some books. Audible is great to listen to books on your phone (and pick them back up where you fell asleep =). Music is great, too.
wear sunglasses after photo
Because of the medication, you will be hypersensitive to UV rays, so you should avoid being in the sun. Additionally, there is an indication that patients are more susceptible to cateracts after photopheresis and, for that reason, should always wear sunglasses after a photopheresis treatment.